tools/ninja: update to 1.11.0

Updated patchset to latest.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

2 files changed, 3081 insertions, 1070 deletions

diff --git a/tools/ninja/Makefile b/tools/ninja/Makefile
index 0ff642a740..c5c83d9b14 100644
--- a/tools/ninja/Makefile
+++ b/tools/ninja/Makefile
@@ -1,12 +1,12 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=ninja
-PKG_VERSION:=1.10.2
+PKG_VERSION:=1.11.0
 PKG_RELEASE:=1
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL:=https://codeload.github.com/ninja-build/ninja/tar.gz/v$(PKG_VERSION)?
-PKG_HASH:=ce35865411f0490368a8fc383f29071de6690cbadc27704734978221f25e2bed
+PKG_HASH:=3c6ba2e66400fe3f1ae83deb4b235faf3137ec20bd5b08c29bfc368db143e4c6
 
 include $(INCLUDE_DIR)/host-build.mk
 
diff --git a/tools/ninja/patches/100-make_jobserver_support.patch b/tools/ninja/patches/100-make_jobserver_support.patch
index ecceaf23ca..7dac8ef814 100644
--- a/tools/ninja/patches/100-make_jobserver_support.patch
+++ b/tools/ninja/patches/100-make_jobserver_support.patch
@@ -1,7 +1,7 @@
-From c1a081c00f803fc28e51f155f25abe8346ce5f13 Mon Sep 17 00:00:00 2001
+From 17d13fd7881fd3ce9f9b9d44ce435d6caf4b8f28 Mon Sep 17 00:00:00 2001
 From: Stefan Becker <stefanb@gpartner-nvidia.com>
 Date: Tue, 22 Mar 2016 13:48:07 +0200
-Subject: [PATCH] Add GNU make jobserver client support
+Subject: [PATCH 01/11] Add GNU make jobserver client support
 
 - add new TokenPool interface
 - GNU make implementation for TokenPool parses and verifies the magic
@@ -19,263 +19,60 @@ Documentation for GNU make jobserver
   http://make.mad-scientist.net/papers/jobserver-implementation/
 
 Fixes https://github.com/ninja-build/ninja/issues/1139
-
-Add TokenPool monitoring to SubprocessSet::DoWork()
-
-Improve on the original jobserver client implementation. This makes
-ninja a more aggressive GNU make jobserver client.
-
-- add monitor interface to TokenPool
-- TokenPool is passed down when main loop indicates that more work is
-  ready and would be allowed to start if a token becomes available
-- posix: update DoWork() to monitor TokenPool read file descriptor
-- WaitForCommand() exits when DoWork() sets token flag
-- Main loop starts over when WaitForCommand() sets token exit status
-
-Ignore jobserver when -jN is forced on command line
-
-This emulates the behaviour of GNU make.
-
-- add parallelism_from_cmdline flag to build configuration
-- set the flag when -jN is given on command line
-- pass the flag to TokenPool::Get()
-- GNUmakeTokenPool::Setup()
-  * prints a warning when the flag is true and jobserver was detected
-  * returns false, i.e. jobserver will be ignored
-- ignore config.parallelism in CanRunMore() when we have a valid
-  TokenPool, because it gets always initialized to a default when not
-  given on the command line
-
-Honor -lN from MAKEFLAGS
-
-This emulates the behaviour of GNU make.
-
-- build: make a copy of max_load_average and pass it to TokenPool.
-- GNUmakeTokenPool: if we detect a jobserver and a valid -lN argument in
-  MAKEFLAGS then set max_load_average to N.
-
-Use LinePrinter for TokenPool messages
-
-- replace printf() with calls to LinePrinter
-- print GNU make jobserver message only when verbose build is requested
-
-Prepare PR for merging
-
-- fix Windows build error in no-op TokenPool implementation
-- improve Acquire() to block for a maximum of 100ms
-- address review comments
-
-Add tests for TokenPool
-
-- TokenPool setup
-- GetMonitorFd() API
-- implicit token and tokens in jobserver pipe
-- Acquire() / Reserve() / Release() protocol
-- Clear() API
-
-Add tests for subprocess module
-
-- add TokenPoolTest stub to provide TokenPool::GetMonitorFd()
-- add two tests
-  * both tests set up a dummy GNUmake jobserver pipe
-  * both tests call DoWork() with TokenPoolTest
-  * test 1: verify that DoWork() detects when a token is available
-  * test 2: verify that DoWork() works as before without a token
-- the tests are not compiled in under Windows
-
-Add tests for build module
-
-Add tests that verify the token functionality of the builder main loop.
-We replace the default fake command runner with a special version where
-the tests can control each call to AcquireToken(), CanRunMore() and
-WaitForCommand().
-
-Add Win32 implementation for GNUmakeTokenPool
-
-GNU make uses a semaphore as jobserver protocol on Win32. See also
-
-   https://www.gnu.org/software/make/manual/html_node/Windows-Jobserver.html
-
-Usage is pretty simple and straightforward, i.e. WaitForSingleObject()
-to obtain a token and ReleaseSemaphore() to return it.
-
-Unfortunately subprocess-win32.cc uses an I/O completion port (IOCP).
-IOCPs aren't waitable objects, i.e. we can't use WaitForMultipleObjects()
-to wait on the IOCP and the token semaphore at the same time.
-
-Therefore GNUmakeTokenPoolWin32 creates a child thread that waits on the
-token semaphore and posts a dummy I/O completion status on the IOCP when
-it was able to obtain a token. That unblocks SubprocessSet::DoWork() and
-it can then check if a token became available or not.
-
-- split existing GNUmakeTokenPool into common and platform bits
-- add GNUmakeTokenPool interface
-- move the Posix bits to GNUmakeTokenPoolPosix
-- add the Win32 bits as GNUmakeTokenPoolWin32
-- move Setup() method up to TokenPool interface
-- update Subprocess & TokenPool tests accordingly
-
-Prepare PR for merging - part II
-
-- remove unnecessary "struct" from TokenPool
-- add PAPCFUNC cast to QueryUserAPC()
-- remove hard-coded MAKEFLAGS string from win32
-- remove useless build test CompleteNoWork
-- rename TokenPoolTest to TestTokenPool
-- add tokenpool modules to CMake build
-- remove unused no-op TokenPool implementation
-- address review comments from
-
-https://github.com/ninja-build/ninja/pull/1140#pullrequestreview-195195803
-https://github.com/ninja-build/ninja/pull/1140#pullrequestreview-185089255
-https://github.com/ninja-build/ninja/pull/1140#issuecomment-473898963
-https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
 ---
- CMakeLists.txt                  |   8 +-
- configure.py                    |   7 +-
- src/build.cc                    | 127 ++++++++---
- src/build.h                     |  12 +-
- src/build_test.cc               | 363 +++++++++++++++++++++++++++++++-
- src/exit_status.h               |   3 +-
- src/ninja.cc                    |   1 +
- src/subprocess-posix.cc         |  33 ++-
- src/subprocess-win32.cc         |  11 +-
- src/subprocess.h                |   8 +-
- src/subprocess_test.cc          | 149 +++++++++++--
- src/tokenpool-gnu-make-posix.cc | 202 ++++++++++++++++++
- src/tokenpool-gnu-make-win32.cc | 239 +++++++++++++++++++++
- src/tokenpool-gnu-make.cc       | 108 ++++++++++
- src/tokenpool-gnu-make.h        |  40 ++++
- src/tokenpool.h                 |  42 ++++
- src/tokenpool_test.cc           | 269 +++++++++++++++++++++++
- 17 files changed, 1562 insertions(+), 60 deletions(-)
- create mode 100644 src/tokenpool-gnu-make-posix.cc
- create mode 100644 src/tokenpool-gnu-make-win32.cc
+ configure.py              |   2 +
+ src/build.cc              |  63 ++++++++----
+ src/build.h               |   3 +
+ src/tokenpool-gnu-make.cc | 211 ++++++++++++++++++++++++++++++++++++++
+ src/tokenpool-none.cc     |  27 +++++
+ src/tokenpool.h           |  26 +++++
+ 6 files changed, 310 insertions(+), 22 deletions(-)
  create mode 100644 src/tokenpool-gnu-make.cc
- create mode 100644 src/tokenpool-gnu-make.h
+ create mode 100644 src/tokenpool-none.cc
  create mode 100644 src/tokenpool.h
- create mode 100644 src/tokenpool_test.cc
 
---- a/CMakeLists.txt
-+++ b/CMakeLists.txt
-@@ -94,6 +94,7 @@ add_library(libninja OBJECT
- 	src/parser.cc
- 	src/state.cc
- 	src/string_piece_util.cc
-+	src/tokenpool-gnu-make.cc
- 	src/util.cc
- 	src/version.cc
- )
-@@ -104,12 +105,16 @@ if(WIN32)
- 		src/msvc_helper-win32.cc
- 		src/msvc_helper_main-win32.cc
- 		src/getopt.c
-+		src/tokenpool-gnu-make-win32.cc
- 	)
- 	if(MSVC)
- 		target_sources(libninja PRIVATE src/minidump-win32.cc)
- 	endif()
- else()
--	target_sources(libninja PRIVATE src/subprocess-posix.cc)
-+	target_sources(libninja PRIVATE
-+		src/subprocess-posix.cc
-+		src/tokenpool-gnu-make-posix.cc
-+	)
- 	if(CMAKE_SYSTEM_NAME STREQUAL "OS400" OR CMAKE_SYSTEM_NAME STREQUAL "AIX")
- 		target_sources(libninja PRIVATE src/getopt.c)
- 	endif()
-@@ -182,6 +187,7 @@ if(BUILD_TESTING)
-     src/string_piece_util_test.cc
-     src/subprocess_test.cc
-     src/test.cc
-+    src/tokenpool_test.cc
-     src/util_test.cc
-   )
-   if(WIN32)
+diff --git a/configure.py b/configure.py
+index 43904349a8..db3492c93c 100755
 --- a/configure.py
 +++ b/configure.py
-@@ -514,11 +514,13 @@ for name in ['build',
-              'parser',
-              'state',
-              'string_piece_util',
-+             'tokenpool-gnu-make',
-              'util',
-              'version']:
+@@ -522,6 +522,7 @@ def has_re2c():
      objs += cxx(name, variables=cxxvariables)
  if platform.is_windows():
      for name in ['subprocess-win32',
-+                 'tokenpool-gnu-make-win32',
++                 'tokenpool-none',
                   'includes_normalize-win32',
                   'msvc_helper-win32',
                   'msvc_helper_main-win32']:
-@@ -527,7 +529,9 @@ if platform.is_windows():
-         objs += cxx('minidump-win32', variables=cxxvariables)
+@@ -531,6 +532,7 @@ def has_re2c():
      objs += cc('getopt')
  else:
--    objs += cxx('subprocess-posix')
-+    for name in ['subprocess-posix',
-+                 'tokenpool-gnu-make-posix']:
-+        objs += cxx(name)
+     objs += cxx('subprocess-posix')
++    objs += cxx('tokenpool-gnu-make')
  if platform.is_aix():
      objs += cc('getopt')
  if platform.is_msvc():
-@@ -582,6 +586,7 @@ for name in ['build_log_test',
-              'string_piece_util_test',
-              'subprocess_test',
-              'test',
-+             'tokenpool_test',
-              'util_test']:
-     objs += cxx(name, variables=cxxvariables)
- if platform.is_windows():
+diff --git a/src/build.cc b/src/build.cc
+index 6f11ed7a3c..fa096eac33 100644
 --- a/src/build.cc
 +++ b/src/build.cc
-@@ -38,6 +38,7 @@
- #include "graph.h"
+@@ -35,6 +35,7 @@
  #include "state.h"
+ #include "status.h"
  #include "subprocess.h"
 +#include "tokenpool.h"
  #include "util.h"
  
  using namespace std;
-@@ -50,8 +51,9 @@ struct DryRunCommandRunner : public Comm
- 
-   // Overridden from CommandRunner:
-   virtual bool CanRunMore() const;
-+  virtual bool AcquireToken();
-   virtual bool StartCommand(Edge* edge);
--  virtual bool WaitForCommand(Result* result);
-+  virtual bool WaitForCommand(Result* result, bool more_ready);
- 
-  private:
-   queue<Edge*> finished_;
-@@ -61,12 +63,16 @@ bool DryRunCommandRunner::CanRunMore() c
-   return true;
- }
- 
-+bool DryRunCommandRunner::AcquireToken() {
-+  return true;
-+}
-+
- bool DryRunCommandRunner::StartCommand(Edge* edge) {
-   finished_.push(edge);
-   return true;
- }
- 
--bool DryRunCommandRunner::WaitForCommand(Result* result) {
-+bool DryRunCommandRunner::WaitForCommand(Result* result, bool more_ready) {
-    if (finished_.empty())
-      return false;
- 
-@@ -379,7 +385,7 @@ void Plan::EdgeWanted(const Edge* edge)
+@@ -149,7 +150,7 @@ void Plan::EdgeWanted(const Edge* edge) {
  }
  
  Edge* Plan::FindWork() {
 -  if (ready_.empty())
 +  if (!more_ready())
      return NULL;
-   set<Edge*>::iterator e = ready_.begin();
+   EdgeSet::iterator e = ready_.begin();
    Edge* edge = *e;
-@@ -665,19 +671,39 @@ void Plan::Dump() const {
+@@ -448,8 +449,8 @@ void Plan::Dump() const {
  }
  
  struct RealCommandRunner : public CommandRunner {
@@ -284,31 +81,18 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
 +  explicit RealCommandRunner(const BuildConfig& config);
 +  virtual ~RealCommandRunner();
    virtual bool CanRunMore() const;
-+  virtual bool AcquireToken();
    virtual bool StartCommand(Edge* edge);
--  virtual bool WaitForCommand(Result* result);
-+  virtual bool WaitForCommand(Result* result, bool more_ready);
-   virtual vector<Edge*> GetActiveEdges();
-   virtual void Abort();
+   virtual bool WaitForCommand(Result* result);
+@@ -458,9 +459,18 @@ struct RealCommandRunner : public CommandRunner {
  
    const BuildConfig& config_;
-+  // copy of config_.max_load_average; can be modified by TokenPool setup
-+  double max_load_average_;
    SubprocessSet subprocs_;
-+  TokenPool* tokens_;
++  TokenPool *tokens_;
    map<const Subprocess*, Edge*> subproc_to_edge_;
  };
  
 +RealCommandRunner::RealCommandRunner(const BuildConfig& config) : config_(config) {
-+  max_load_average_ = config.max_load_average;
-+  if ((tokens_ = TokenPool::Get()) != NULL) {
-+    if (!tokens_->Setup(config_.parallelism_from_cmdline,
-+                        config_.verbosity == BuildConfig::VERBOSE,
-+                        max_load_average_)) {
-+      delete tokens_;
-+      tokens_ = NULL;
-+    }
-+  }
++  tokens_ = TokenPool::Get();
 +}
 +
 +RealCommandRunner::~RealCommandRunner() {
@@ -318,7 +102,7 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
  vector<Edge*> RealCommandRunner::GetActiveEdges() {
    vector<Edge*> edges;
    for (map<const Subprocess*, Edge*>::iterator e = subproc_to_edge_.begin();
-@@ -688,14 +714,23 @@ vector<Edge*> RealCommandRunner::GetActi
+@@ -471,14 +481,18 @@ vector<Edge*> RealCommandRunner::GetActiveEdges() {
  
  void RealCommandRunner::Abort() {
    subprocs_.Clear();
@@ -327,27 +111,19 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
  }
  
  bool RealCommandRunner::CanRunMore() const {
--  size_t subproc_number =
--      subprocs_.running_.size() + subprocs_.finished_.size();
--  return (int)subproc_number < config_.parallelism
+   size_t subproc_number =
+       subprocs_.running_.size() + subprocs_.finished_.size();
+   return (int)subproc_number < config_.parallelism
 -    && ((subprocs_.running_.empty() || config_.max_load_average <= 0.0f)
 -        || GetLoadAverage() < config_.max_load_average);
-+  bool parallelism_limit_not_reached =
-+    tokens_ || // ignore config_.parallelism
-+    ((int) (subprocs_.running_.size() +
-+            subprocs_.finished_.size()) < config_.parallelism);
-+  return parallelism_limit_not_reached
 +    && (subprocs_.running_.empty() ||
-+        (max_load_average_ <= 0.0f ||
-+         GetLoadAverage() < max_load_average_));
-+}
-+
-+bool RealCommandRunner::AcquireToken() {
-+  return (!tokens_ || tokens_->Acquire());
++        ((config_.max_load_average <= 0.0f ||
++          GetLoadAverage() < config_.max_load_average)
++      && (!tokens_ || tokens_->Acquire())));
  }
  
  bool RealCommandRunner::StartCommand(Edge* edge) {
-@@ -703,19 +738,33 @@ bool RealCommandRunner::StartCommand(Edg
+@@ -486,6 +500,8 @@ bool RealCommandRunner::StartCommand(Edge* edge) {
    Subprocess* subproc = subprocs_.Add(command, edge->use_console());
    if (!subproc)
      return false;
@@ -356,63 +132,37 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
    subproc_to_edge_.insert(make_pair(subproc, edge));
  
    return true;
- }
- 
--bool RealCommandRunner::WaitForCommand(Result* result) {
-+bool RealCommandRunner::WaitForCommand(Result* result, bool more_ready) {
-   Subprocess* subproc;
--  while ((subproc = subprocs_.NextFinished()) == NULL) {
--    bool interrupted = subprocs_.DoWork();
-+  subprocs_.ResetTokenAvailable();
-+  while (((subproc = subprocs_.NextFinished()) == NULL) &&
-+         !subprocs_.IsTokenAvailable()) {
-+    bool interrupted = subprocs_.DoWork(more_ready ? tokens_ : NULL);
-     if (interrupted)
+@@ -499,6 +515,9 @@ bool RealCommandRunner::WaitForCommand(Result* result) {
        return false;
    }
  
-+  // token became available
-+  if (subproc == NULL) {
-+    result->status = ExitTokenAvailable;
-+    return true;
-+  }
-+
-+  // command completed
 +  if (tokens_)
 +    tokens_->Release();
 +
    result->status = subproc->Finish();
    result->output = subproc->GetOutput();
  
-@@ -825,38 +874,42 @@ bool Builder::Build(string* err) {
-   // command runner.
+@@ -621,31 +640,31 @@ bool Builder::Build(string* err) {
    // Second, we attempt to wait for / reap the next finished command.
    while (plan_.more_to_do()) {
--    // See if we can start any more commands.
+     // See if we can start any more commands.
 -    if (failures_allowed && command_runner_->CanRunMore()) {
 -      if (Edge* edge = plan_.FindWork()) {
 -        if (edge->GetBindingBool("generator")) {
--          scan_.build_log()->Close();
--        }
-+    // See if we can start any more commands...
-+    bool can_run_more =
-+        failures_allowed   &&
-+        plan_.more_ready() &&
-+        command_runner_->CanRunMore();
-+
-+    // ... but we also need a token to do that.
-+    if (can_run_more && command_runner_->AcquireToken()) {
++    if (failures_allowed && plan_.more_ready() &&
++        command_runner_->CanRunMore()) {
 +      Edge* edge = plan_.FindWork();
 +      if (edge->GetBindingBool("generator")) {
-+        scan_.build_log()->Close();
-+      }
+           scan_.build_log()->Close();
+         }
+ 
+-        if (!StartEdge(edge, err)) {
 +      if (!StartEdge(edge, err)) {
 +        Cleanup();
 +        status_->BuildFinished();
 +        return false;
 +      }
- 
--        if (!StartEdge(edge, err)) {
++
 +      if (edge->is_phony()) {
 +        if (!plan_.EdgeFinished(edge, Plan::kEdgeSucceeded, err)) {
            Cleanup();
@@ -441,6 +191,437 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
      }
  
      // See if we can reap any finished commands.
+diff --git a/src/build.h b/src/build.h
+index d697dfb89e..7dcd111e61 100644
+--- a/src/build.h
++++ b/src/build.h
+@@ -52,6 +52,9 @@ struct Plan {
+   /// Returns true if there's more work to be done.
+   bool more_to_do() const { return wanted_edges_ > 0 && command_edges_ > 0; }
+ 
++  /// Returns true if there's more edges ready to start
++  bool more_ready() const { return !ready_.empty(); }
++
+   /// Dumps the current state of the plan.
+   void Dump() const;
+ 
+diff --git a/src/tokenpool-gnu-make.cc b/src/tokenpool-gnu-make.cc
+new file mode 100644
+index 0000000000..a8f9b7139d
+--- /dev/null
++++ b/src/tokenpool-gnu-make.cc
+@@ -0,0 +1,211 @@
++// Copyright 2016 Google Inc. All Rights Reserved.
++//
++// Licensed under the Apache License, Version 2.0 (the "License");
++// you may not use this file except in compliance with the License.
++// You may obtain a copy of the License at
++//
++//     http://www.apache.org/licenses/LICENSE-2.0
++//
++// Unless required by applicable law or agreed to in writing, software
++// distributed under the License is distributed on an "AS IS" BASIS,
++// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
++// See the License for the specific language governing permissions and
++// limitations under the License.
++
++#include "tokenpool.h"
++
++#include <errno.h>
++#include <fcntl.h>
++#include <poll.h>
++#include <unistd.h>
++#include <signal.h>
++#include <stdio.h>
++#include <string.h>
++#include <stdlib.h>
++
++// TokenPool implementation for GNU make jobserver
++// (http://make.mad-scientist.net/papers/jobserver-implementation/)
++struct GNUmakeTokenPool : public TokenPool {
++  GNUmakeTokenPool();
++  virtual ~GNUmakeTokenPool();
++
++  virtual bool Acquire();
++  virtual void Reserve();
++  virtual void Release();
++  virtual void Clear();
++
++  bool Setup();
++
++ private:
++  int available_;
++  int used_;
++
++#ifdef _WIN32
++  // @TODO
++#else
++  int rfd_;
++  int wfd_;
++
++  struct sigaction old_act_;
++  bool restore_;
++
++  static int dup_rfd_;
++  static void CloseDupRfd(int signum);
++
++  bool CheckFd(int fd);
++  bool SetAlarmHandler();
++#endif
++
++  void Return();
++};
++
++// every instance owns an implicit token -> available_ == 1
++GNUmakeTokenPool::GNUmakeTokenPool() : available_(1), used_(0),
++                                       rfd_(-1), wfd_(-1), restore_(false) {
++}
++
++GNUmakeTokenPool::~GNUmakeTokenPool() {
++  Clear();
++  if (restore_)
++    sigaction(SIGALRM, &old_act_, NULL);
++}
++
++bool GNUmakeTokenPool::CheckFd(int fd) {
++  if (fd < 0)
++    return false;
++  int ret = fcntl(fd, F_GETFD);
++  if (ret < 0)
++    return false;
++  return true;
++}
++
++int GNUmakeTokenPool::dup_rfd_ = -1;
++
++void GNUmakeTokenPool::CloseDupRfd(int signum) {
++  close(dup_rfd_);
++  dup_rfd_ = -1;
++}
++
++bool GNUmakeTokenPool::SetAlarmHandler() {
++  struct sigaction act;
++  memset(&act, 0, sizeof(act));
++  act.sa_handler = CloseDupRfd;
++  if (sigaction(SIGALRM, &act, &old_act_) < 0) {
++    perror("sigaction:");
++    return(false);
++  } else {
++    restore_ = true;
++    return(true);
++  }
++}
++
++bool GNUmakeTokenPool::Setup() {
++  const char *value = getenv("MAKEFLAGS");
++  if (value) {
++    // GNU make <= 4.1
++    const char *jobserver = strstr(value, "--jobserver-fds=");
++    // GNU make => 4.2
++    if (!jobserver)
++      jobserver = strstr(value, "--jobserver-auth=");
++    if (jobserver) {
++      int rfd = -1;
++      int wfd = -1;
++      if ((sscanf(jobserver, "%*[^=]=%d,%d", &rfd, &wfd) == 2) &&
++          CheckFd(rfd) &&
++          CheckFd(wfd) &&
++          SetAlarmHandler()) {
++        printf("ninja: using GNU make jobserver.\n");
++        rfd_ = rfd;
++        wfd_ = wfd;
++        return true;
++      }
++    }
++  }
++
++  return false;
++}
++
++bool GNUmakeTokenPool::Acquire() {
++  if (available_ > 0)
++    return true;
++
++#ifdef USE_PPOLL
++  pollfd pollfds[] = {{rfd_, POLLIN, 0}};
++  int ret = poll(pollfds, 1, 0);
++#else
++  fd_set set;
++  struct timeval timeout = { 0, 0 };
++  FD_ZERO(&set);
++  FD_SET(rfd_, &set);
++  int ret = select(rfd_ + 1, &set, NULL, NULL, &timeout);
++#endif
++  if (ret > 0) {
++    dup_rfd_ = dup(rfd_);
++
++    if (dup_rfd_ != -1) {
++      struct sigaction act, old_act;
++      int ret = 0;
++
++      memset(&act, 0, sizeof(act));
++      act.sa_handler = CloseDupRfd;
++      if (sigaction(SIGCHLD, &act, &old_act) == 0) {
++        char buf;
++
++        // block until token read, child exits or timeout
++        alarm(1);
++        ret = read(dup_rfd_, &buf, 1);
++        alarm(0);
++
++        sigaction(SIGCHLD, &old_act, NULL);
++      }
++
++      CloseDupRfd(0);
++
++      if (ret > 0) {
++        available_++;
++        return true;
++      }
++    }
++  }
++  return false;
++}
++
++void GNUmakeTokenPool::Reserve() {
++  available_--;
++  used_++;
++}
++
++void GNUmakeTokenPool::Return() {
++  const char buf = '+';
++  while (1) {
++    int ret = write(wfd_, &buf, 1);
++    if (ret > 0)
++      available_--;
++    if ((ret != -1) || (errno != EINTR))
++      return;
++    // write got interrupted - retry
++  }
++}
++
++void GNUmakeTokenPool::Release() {
++  available_++;
++  used_--;
++  if (available_ > 1)
++    Return();
++}
++
++void GNUmakeTokenPool::Clear() {
++  while (used_ > 0)
++    Release();
++  while (available_ > 1)
++    Return();
++}
++
++struct TokenPool *TokenPool::Get(void) {
++  GNUmakeTokenPool *tokenpool = new GNUmakeTokenPool;
++  if (tokenpool->Setup())
++    return tokenpool;
++  else
++    delete tokenpool;
++  return NULL;
++}
+diff --git a/src/tokenpool-none.cc b/src/tokenpool-none.cc
+new file mode 100644
+index 0000000000..602b3316f5
+--- /dev/null
++++ b/src/tokenpool-none.cc
+@@ -0,0 +1,27 @@
++// Copyright 2016 Google Inc. All Rights Reserved.
++//
++// Licensed under the Apache License, Version 2.0 (the "License");
++// you may not use this file except in compliance with the License.
++// You may obtain a copy of the License at
++//
++//     http://www.apache.org/licenses/LICENSE-2.0
++//
++// Unless required by applicable law or agreed to in writing, software
++// distributed under the License is distributed on an "AS IS" BASIS,
++// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
++// See the License for the specific language governing permissions and
++// limitations under the License.
++
++#include "tokenpool.h"
++
++#include <fcntl.h>
++#include <poll.h>
++#include <unistd.h>
++#include <stdio.h>
++#include <string.h>
++#include <stdlib.h>
++
++// No-op TokenPool implementation
++struct TokenPool *TokenPool::Get(void) {
++  return NULL;
++}
+diff --git a/src/tokenpool.h b/src/tokenpool.h
+new file mode 100644
+index 0000000000..f560b1083b
+--- /dev/null
++++ b/src/tokenpool.h
+@@ -0,0 +1,26 @@
++// Copyright 2016 Google Inc. All Rights Reserved.
++//
++// Licensed under the Apache License, Version 2.0 (the "License");
++// you may not use this file except in compliance with the License.
++// You may obtain a copy of the License at
++//
++//     http://www.apache.org/licenses/LICENSE-2.0
++//
++// Unless required by applicable law or agreed to in writing, software
++// distributed under the License is distributed on an "AS IS" BASIS,
++// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
++// See the License for the specific language governing permissions and
++// limitations under the License.
++
++// interface to token pool
++struct TokenPool {
++  virtual ~TokenPool() {}
++
++  virtual bool Acquire() = 0;
++  virtual void Reserve() = 0;
++  virtual void Release() = 0;
++  virtual void Clear() = 0;
++
++  // returns NULL if token pool is not available
++  static struct TokenPool *Get(void);
++};
+
+From ccaccc610cd456f6068758f82e72006364c7380b Mon Sep 17 00:00:00 2001
+From: Stefan Becker <stefanb@gpartner-nvidia.com>
+Date: Fri, 27 May 2016 16:47:10 +0300
+Subject: [PATCH 02/11] Add TokenPool monitoring to SubprocessSet::DoWork()
+
+Improve on the original jobserver client implementation. This makes
+ninja a more aggressive GNU make jobserver client.
+
+- add monitor interface to TokenPool
+- TokenPool is passed down when main loop indicates that more work is
+  ready and would be allowed to start if a token becomes available
+- posix: update DoWork() to monitor TokenPool read file descriptor
+- WaitForCommand() exits when DoWork() sets token flag
+- Main loop starts over when WaitForCommand() sets token exit status
+---
+ src/build.cc              | 53 +++++++++++++++++++++++++++++----------
+ src/build.h               |  3 ++-
+ src/build_test.cc         |  9 +++++--
+ src/exit_status.h         |  3 ++-
+ src/subprocess-posix.cc   | 33 ++++++++++++++++++++++--
+ src/subprocess-win32.cc   |  2 +-
+ src/subprocess.h          |  8 +++++-
+ src/subprocess_test.cc    | 47 +++++++++++++++++++++++-----------
+ src/tokenpool-gnu-make.cc |  5 ++++
+ src/tokenpool.h           |  6 +++++
+ 10 files changed, 134 insertions(+), 35 deletions(-)
+
+diff --git a/src/build.cc b/src/build.cc
+index fa096eac33..a25c349050 100644
+--- a/src/build.cc
++++ b/src/build.cc
+@@ -48,8 +48,9 @@ struct DryRunCommandRunner : public CommandRunner {
+ 
+   // Overridden from CommandRunner:
+   virtual bool CanRunMore() const;
++  virtual bool AcquireToken();
+   virtual bool StartCommand(Edge* edge);
+-  virtual bool WaitForCommand(Result* result);
++  virtual bool WaitForCommand(Result* result, bool more_ready);
+ 
+  private:
+   queue<Edge*> finished_;
+@@ -59,12 +60,16 @@ bool DryRunCommandRunner::CanRunMore() const {
+   return true;
+ }
+ 
++bool DryRunCommandRunner::AcquireToken() {
++  return true;
++}
++
+ bool DryRunCommandRunner::StartCommand(Edge* edge) {
+   finished_.push(edge);
+   return true;
+ }
+ 
+-bool DryRunCommandRunner::WaitForCommand(Result* result) {
++bool DryRunCommandRunner::WaitForCommand(Result* result, bool more_ready) {
+    if (finished_.empty())
+      return false;
+ 
+@@ -452,8 +457,9 @@ struct RealCommandRunner : public CommandRunner {
+   explicit RealCommandRunner(const BuildConfig& config);
+   virtual ~RealCommandRunner();
+   virtual bool CanRunMore() const;
++  virtual bool AcquireToken();
+   virtual bool StartCommand(Edge* edge);
+-  virtual bool WaitForCommand(Result* result);
++  virtual bool WaitForCommand(Result* result, bool more_ready);
+   virtual vector<Edge*> GetActiveEdges();
+   virtual void Abort();
+ 
+@@ -490,9 +496,12 @@ bool RealCommandRunner::CanRunMore() const {
+       subprocs_.running_.size() + subprocs_.finished_.size();
+   return (int)subproc_number < config_.parallelism
+     && (subprocs_.running_.empty() ||
+-        ((config_.max_load_average <= 0.0f ||
+-          GetLoadAverage() < config_.max_load_average)
+-      && (!tokens_ || tokens_->Acquire())));
++        (config_.max_load_average <= 0.0f ||
++         GetLoadAverage() < config_.max_load_average));
++}
++
++bool RealCommandRunner::AcquireToken() {
++  return (!tokens_ || tokens_->Acquire());
+ }
+ 
+ bool RealCommandRunner::StartCommand(Edge* edge) {
+@@ -507,14 +516,23 @@ bool RealCommandRunner::StartCommand(Edge* edge) {
+   return true;
+ }
+ 
+-bool RealCommandRunner::WaitForCommand(Result* result) {
++bool RealCommandRunner::WaitForCommand(Result* result, bool more_ready) {
+   Subprocess* subproc;
+-  while ((subproc = subprocs_.NextFinished()) == NULL) {
+-    bool interrupted = subprocs_.DoWork();
++  subprocs_.ResetTokenAvailable();
++  while (((subproc = subprocs_.NextFinished()) == NULL) &&
++         !subprocs_.IsTokenAvailable()) {
++    bool interrupted = subprocs_.DoWork(more_ready ? tokens_ : NULL);
+     if (interrupted)
+       return false;
+   }
+ 
++  // token became available
++  if (subproc == NULL) {
++    result->status = ExitTokenAvailable;
++    return true;
++  }
++
++  // command completed
+   if (tokens_)
+     tokens_->Release();
+ 
+@@ -639,9 +657,14 @@ bool Builder::Build(string* err) {
+   // command runner.
+   // Second, we attempt to wait for / reap the next finished command.
+   while (plan_.more_to_do()) {
+-    // See if we can start any more commands.
+-    if (failures_allowed && plan_.more_ready() &&
+-        command_runner_->CanRunMore()) {
++    // See if we can start any more commands...
++    bool can_run_more =
++        failures_allowed   &&
++        plan_.more_ready() &&
++        command_runner_->CanRunMore();
++
++    // ... but we also need a token to do that.
++    if (can_run_more && command_runner_->AcquireToken()) {
+       Edge* edge = plan_.FindWork();
+       if (edge->GetBindingBool("generator")) {
+           scan_.build_log()->Close();
+@@ -670,7 +693,7 @@ bool Builder::Build(string* err) {
+     // See if we can reap any finished commands.
      if (pending_commands) {
        CommandRunner::Result result;
 -      if (!command_runner_->WaitForCommand(&result) ||
@@ -448,7 +629,7 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
            result.status == ExitInterrupted) {
          Cleanup();
          status_->BuildFinished();
-@@ -864,6 +917,10 @@ bool Builder::Build(string* err) {
+@@ -678,6 +701,10 @@ bool Builder::Build(string* err) {
          return false;
        }
  
@@ -459,19 +640,11 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
        --pending_commands;
        if (!FinishCommand(&result, err)) {
          Cleanup();
+diff --git a/src/build.h b/src/build.h
+index 7dcd111e61..35c7b97d12 100644
 --- a/src/build.h
 +++ b/src/build.h
-@@ -55,6 +55,9 @@ struct Plan {
-   /// Returns true if there's more work to be done.
-   bool more_to_do() const { return wanted_edges_ > 0 && command_edges_ > 0; }
- 
-+  /// Returns true if there's more edges ready to start
-+  bool more_ready() const { return !ready_.empty(); }
-+
-   /// Dumps the current state of the plan.
-   void Dump() const;
- 
-@@ -139,6 +142,7 @@ private:
+@@ -139,6 +139,7 @@ struct Plan {
  struct CommandRunner {
    virtual ~CommandRunner() {}
    virtual bool CanRunMore() const = 0;
@@ -479,46 +652,20 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
    virtual bool StartCommand(Edge* edge) = 0;
  
    /// The result of waiting for a command.
-@@ -150,7 +154,9 @@ struct CommandRunner {
+@@ -150,7 +151,7 @@ struct CommandRunner {
      bool success() const { return status == ExitSuccess; }
    };
    /// Wait for a command to complete, or return false if interrupted.
 -  virtual bool WaitForCommand(Result* result) = 0;
-+  /// If more_ready is true then the optional TokenPool is monitored too
-+  /// and we return when a token becomes available.
 +  virtual bool WaitForCommand(Result* result, bool more_ready) = 0;
  
    virtual std::vector<Edge*> GetActiveEdges() { return std::vector<Edge*>(); }
    virtual void Abort() {}
-@@ -158,7 +164,8 @@ struct CommandRunner {
- 
- /// Options (e.g. verbosity, parallelism) passed to a build.
- struct BuildConfig {
--  BuildConfig() : verbosity(NORMAL), dry_run(false), parallelism(1),
-+  BuildConfig() : verbosity(NORMAL), dry_run(false),
-+                  parallelism(1), parallelism_from_cmdline(false),
-                   failures_allowed(1), max_load_average(-0.0f) {}
- 
-   enum Verbosity {
-@@ -169,6 +176,7 @@ struct BuildConfig {
-   Verbosity verbosity;
-   bool dry_run;
-   int parallelism;
-+  bool parallelism_from_cmdline;
-   int failures_allowed;
-   /// The maximum load average we must not exceed. A negative value
-   /// means that we do not have any limit.
+diff --git a/src/build_test.cc b/src/build_test.cc
+index 4ef62b2113..7a5ff4015a 100644
 --- a/src/build_test.cc
 +++ b/src/build_test.cc
-@@ -15,6 +15,7 @@
- #include "build.h"
- 
- #include <assert.h>
-+#include <stdarg.h>
- 
- #include "build_log.h"
- #include "deps_log.h"
-@@ -473,8 +474,9 @@ struct FakeCommandRunner : public Comman
+@@ -474,8 +474,9 @@ struct FakeCommandRunner : public CommandRunner {
  
    // CommandRunner impl
    virtual bool CanRunMore() const;
@@ -529,7 +676,7 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
    virtual vector<Edge*> GetActiveEdges();
    virtual void Abort();
  
-@@ -580,6 +582,10 @@ bool FakeCommandRunner::CanRunMore() con
+@@ -578,6 +579,10 @@ bool FakeCommandRunner::CanRunMore() const {
    return active_edges_.size() < max_active_edges_;
  }
  
@@ -540,7 +687,7 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
  bool FakeCommandRunner::StartCommand(Edge* edge) {
    assert(active_edges_.size() < max_active_edges_);
    assert(find(active_edges_.begin(), active_edges_.end(), edge)
-@@ -625,7 +631,7 @@ bool FakeCommandRunner::StartCommand(Edg
+@@ -649,7 +654,7 @@ bool FakeCommandRunner::StartCommand(Edge* edge) {
    return true;
  }
  
@@ -549,9 +696,1333 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
    if (active_edges_.empty())
      return false;
  
-@@ -3302,3 +3308,356 @@ TEST_F(BuildTest, DyndepTwoLevelDiscover
-   EXPECT_EQ("touch tmp", command_runner_.commands_ran_[3]);
-   EXPECT_EQ("touch out", command_runner_.commands_ran_[4]);
+diff --git a/src/exit_status.h b/src/exit_status.h
+index a714ece791..75ebf6a7a0 100644
+--- a/src/exit_status.h
++++ b/src/exit_status.h
+@@ -18,7 +18,8 @@
+ enum ExitStatus {
+   ExitSuccess,
+   ExitFailure,
+-  ExitInterrupted
++  ExitTokenAvailable,
++  ExitInterrupted,
+ };
+ 
+ #endif  // NINJA_EXIT_STATUS_H_
+diff --git a/src/subprocess-posix.cc b/src/subprocess-posix.cc
+index 8e785406c9..74451b0be2 100644
+--- a/src/subprocess-posix.cc
++++ b/src/subprocess-posix.cc
+@@ -13,6 +13,7 @@
+ // limitations under the License.
+ 
+ #include "subprocess.h"
++#include "tokenpool.h"
+ 
+ #include <sys/select.h>
+ #include <assert.h>
+@@ -249,7 +250,7 @@ Subprocess *SubprocessSet::Add(const string& command, bool use_console) {
+ }
+ 
+ #ifdef USE_PPOLL
+-bool SubprocessSet::DoWork() {
++bool SubprocessSet::DoWork(struct TokenPool* tokens) {
+   vector<pollfd> fds;
+   nfds_t nfds = 0;
+ 
+@@ -263,6 +264,12 @@ bool SubprocessSet::DoWork() {
+     ++nfds;
+   }
+ 
++  if (tokens) {
++    pollfd pfd = { tokens->GetMonitorFd(), POLLIN | POLLPRI, 0 };
++    fds.push_back(pfd);
++    ++nfds;
++  }
++
+   interrupted_ = 0;
+   int ret = ppoll(&fds.front(), nfds, NULL, &old_mask_);
+   if (ret == -1) {
+@@ -295,11 +302,20 @@ bool SubprocessSet::DoWork() {
+     ++i;
+   }
+ 
++  if (tokens) {
++    pollfd *pfd = &fds[nfds - 1];
++    if (pfd->fd >= 0) {
++      assert(pfd->fd == tokens->GetMonitorFd());
++      if (pfd->revents != 0)
++        token_available_ = true;
++    }
++  }
++
+   return IsInterrupted();
+ }
+ 
+ #else  // !defined(USE_PPOLL)
+-bool SubprocessSet::DoWork() {
++bool SubprocessSet::DoWork(struct TokenPool* tokens) {
+   fd_set set;
+   int nfds = 0;
+   FD_ZERO(&set);
+@@ -314,6 +330,13 @@ bool SubprocessSet::DoWork() {
+     }
+   }
+ 
++  if (tokens) {
++    int fd = tokens->GetMonitorFd();
++    FD_SET(fd, &set);
++    if (nfds < fd+1)
++      nfds = fd+1;
++  }
++
+   interrupted_ = 0;
+   int ret = pselect(nfds, &set, 0, 0, 0, &old_mask_);
+   if (ret == -1) {
+@@ -342,6 +365,12 @@ bool SubprocessSet::DoWork() {
+     ++i;
+   }
+ 
++  if (tokens) {
++    int fd = tokens->GetMonitorFd();
++    if ((fd >= 0) && FD_ISSET(fd, &set))
++    token_available_ = true;
++  }
++
+   return IsInterrupted();
+ }
+ #endif  // !defined(USE_PPOLL)
+diff --git a/src/subprocess-win32.cc b/src/subprocess-win32.cc
+index ff3baaca7f..66d2c2c430 100644
+--- a/src/subprocess-win32.cc
++++ b/src/subprocess-win32.cc
+@@ -251,7 +251,7 @@ Subprocess *SubprocessSet::Add(const string& command, bool use_console) {
+   return subprocess;
+ }
+ 
+-bool SubprocessSet::DoWork() {
++bool SubprocessSet::DoWork(struct TokenPool* tokens) {
+   DWORD bytes_read;
+   Subprocess* subproc;
+   OVERLAPPED* overlapped;
+diff --git a/src/subprocess.h b/src/subprocess.h
+index 9e3d2ee98f..9ea67ea477 100644
+--- a/src/subprocess.h
++++ b/src/subprocess.h
+@@ -76,6 +76,8 @@ struct Subprocess {
+   friend struct SubprocessSet;
+ };
+ 
++struct TokenPool;
++
+ /// SubprocessSet runs a ppoll/pselect() loop around a set of Subprocesses.
+ /// DoWork() waits for any state change in subprocesses; finished_
+ /// is a queue of subprocesses as they finish.
+@@ -84,13 +86,17 @@ struct SubprocessSet {
+   ~SubprocessSet();
+ 
+   Subprocess* Add(const std::string& command, bool use_console = false);
+-  bool DoWork();
++  bool DoWork(struct TokenPool* tokens);
+   Subprocess* NextFinished();
+   void Clear();
+ 
+   std::vector<Subprocess*> running_;
+   std::queue<Subprocess*> finished_;
+ 
++  bool token_available_;
++  bool IsTokenAvailable() { return token_available_; }
++  void ResetTokenAvailable() { token_available_ = false; }
++
+ #ifdef _WIN32
+   static BOOL WINAPI NotifyInterrupted(DWORD dwCtrlType);
+   static HANDLE ioport_;
+diff --git a/src/subprocess_test.cc b/src/subprocess_test.cc
+index 073fe86931..4bc8083e26 100644
+--- a/src/subprocess_test.cc
++++ b/src/subprocess_test.cc
+@@ -45,10 +45,12 @@ TEST_F(SubprocessTest, BadCommandStderr) {
+   Subprocess* subproc = subprocs_.Add("cmd /c ninja_no_such_command");
+   ASSERT_NE((Subprocess *) 0, subproc);
+ 
++  subprocs_.ResetTokenAvailable();
+   while (!subproc->Done()) {
+     // Pretend we discovered that stderr was ready for writing.
+-    subprocs_.DoWork();
++    subprocs_.DoWork(NULL);
+   }
++  ASSERT_EQ(false, subprocs_.IsTokenAvailable());
+ 
+   EXPECT_EQ(ExitFailure, subproc->Finish());
+   EXPECT_NE("", subproc->GetOutput());
+@@ -59,10 +61,12 @@ TEST_F(SubprocessTest, NoSuchCommand) {
+   Subprocess* subproc = subprocs_.Add("ninja_no_such_command");
+   ASSERT_NE((Subprocess *) 0, subproc);
+ 
++  subprocs_.ResetTokenAvailable();
+   while (!subproc->Done()) {
+     // Pretend we discovered that stderr was ready for writing.
+-    subprocs_.DoWork();
++    subprocs_.DoWork(NULL);
+   }
++  ASSERT_EQ(false, subprocs_.IsTokenAvailable());
+ 
+   EXPECT_EQ(ExitFailure, subproc->Finish());
+   EXPECT_NE("", subproc->GetOutput());
+@@ -78,9 +82,11 @@ TEST_F(SubprocessTest, InterruptChild) {
+   Subprocess* subproc = subprocs_.Add("kill -INT $$");
+   ASSERT_NE((Subprocess *) 0, subproc);
+ 
++  subprocs_.ResetTokenAvailable();
+   while (!subproc->Done()) {
+-    subprocs_.DoWork();
++    subprocs_.DoWork(NULL);
+   }
++  ASSERT_EQ(false, subprocs_.IsTokenAvailable());
+ 
+   EXPECT_EQ(ExitInterrupted, subproc->Finish());
+ }
+@@ -90,7 +96,7 @@ TEST_F(SubprocessTest, InterruptParent) {
+   ASSERT_NE((Subprocess *) 0, subproc);
+ 
+   while (!subproc->Done()) {
+-    bool interrupted = subprocs_.DoWork();
++    bool interrupted = subprocs_.DoWork(NULL);
+     if (interrupted)
+       return;
+   }
+@@ -102,9 +108,11 @@ TEST_F(SubprocessTest, InterruptChildWithSigTerm) {
+   Subprocess* subproc = subprocs_.Add("kill -TERM $$");
+   ASSERT_NE((Subprocess *) 0, subproc);
+ 
++  subprocs_.ResetTokenAvailable();
+   while (!subproc->Done()) {
+-    subprocs_.DoWork();
++    subprocs_.DoWork(NULL);
+   }
++  ASSERT_EQ(false, subprocs_.IsTokenAvailable());
+ 
+   EXPECT_EQ(ExitInterrupted, subproc->Finish());
+ }
+@@ -114,7 +122,7 @@ TEST_F(SubprocessTest, InterruptParentWithSigTerm) {
+   ASSERT_NE((Subprocess *) 0, subproc);
+ 
+   while (!subproc->Done()) {
+-    bool interrupted = subprocs_.DoWork();
++    bool interrupted = subprocs_.DoWork(NULL);
+     if (interrupted)
+       return;
+   }
+@@ -126,9 +134,11 @@ TEST_F(SubprocessTest, InterruptChildWithSigHup) {
+   Subprocess* subproc = subprocs_.Add("kill -HUP $$");
+   ASSERT_NE((Subprocess *) 0, subproc);
+ 
++  subprocs_.ResetTokenAvailable();
+   while (!subproc->Done()) {
+-    subprocs_.DoWork();
++    subprocs_.DoWork(NULL);
+   }
++  ASSERT_EQ(false, subprocs_.IsTokenAvailable());
+ 
+   EXPECT_EQ(ExitInterrupted, subproc->Finish());
+ }
+@@ -138,7 +148,7 @@ TEST_F(SubprocessTest, InterruptParentWithSigHup) {
+   ASSERT_NE((Subprocess *) 0, subproc);
+ 
+   while (!subproc->Done()) {
+-    bool interrupted = subprocs_.DoWork();
++    bool interrupted = subprocs_.DoWork(NULL);
+     if (interrupted)
+       return;
+   }
+@@ -153,9 +163,11 @@ TEST_F(SubprocessTest, Console) {
+         subprocs_.Add("test -t 0 -a -t 1 -a -t 2", /*use_console=*/true);
+     ASSERT_NE((Subprocess*)0, subproc);
+ 
++    subprocs_.ResetTokenAvailable();
+     while (!subproc->Done()) {
+-      subprocs_.DoWork();
++      subprocs_.DoWork(NULL);
+     }
++    ASSERT_EQ(false, subprocs_.IsTokenAvailable());
+ 
+     EXPECT_EQ(ExitSuccess, subproc->Finish());
+   }
+@@ -167,9 +179,11 @@ TEST_F(SubprocessTest, SetWithSingle) {
+   Subprocess* subproc = subprocs_.Add(kSimpleCommand);
+   ASSERT_NE((Subprocess *) 0, subproc);
+ 
++  subprocs_.ResetTokenAvailable();
+   while (!subproc->Done()) {
+-    subprocs_.DoWork();
++    subprocs_.DoWork(NULL);
+   }
++  ASSERT_EQ(false, subprocs_.IsTokenAvailable());
+   ASSERT_EQ(ExitSuccess, subproc->Finish());
+   ASSERT_NE("", subproc->GetOutput());
+ 
+@@ -200,12 +214,13 @@ TEST_F(SubprocessTest, SetWithMulti) {
+     ASSERT_EQ("", processes[i]->GetOutput());
+   }
+ 
++  subprocs_.ResetTokenAvailable();
+   while (!processes[0]->Done() || !processes[1]->Done() ||
+          !processes[2]->Done()) {
+     ASSERT_GT(subprocs_.running_.size(), 0u);
+-    subprocs_.DoWork();
++    subprocs_.DoWork(NULL);
+   }
+-
++  ASSERT_EQ(false, subprocs_.IsTokenAvailable());
+   ASSERT_EQ(0u, subprocs_.running_.size());
+   ASSERT_EQ(3u, subprocs_.finished_.size());
+ 
+@@ -237,8 +252,10 @@ TEST_F(SubprocessTest, SetWithLots) {
+     ASSERT_NE((Subprocess *) 0, subproc);
+     procs.push_back(subproc);
+   }
++  subprocs_.ResetTokenAvailable();
+   while (!subprocs_.running_.empty())
+-    subprocs_.DoWork();
++    subprocs_.DoWork(NULL);
++  ASSERT_EQ(false, subprocs_.IsTokenAvailable());
+   for (size_t i = 0; i < procs.size(); ++i) {
+     ASSERT_EQ(ExitSuccess, procs[i]->Finish());
+     ASSERT_NE("", procs[i]->GetOutput());
+@@ -254,9 +271,11 @@ TEST_F(SubprocessTest, SetWithLots) {
+ // that stdin is closed.
+ TEST_F(SubprocessTest, ReadStdin) {
+   Subprocess* subproc = subprocs_.Add("cat -");
++  subprocs_.ResetTokenAvailable();
+   while (!subproc->Done()) {
+-    subprocs_.DoWork();
++    subprocs_.DoWork(NULL);
+   }
++  ASSERT_EQ(false, subprocs_.IsTokenAvailable());
+   ASSERT_EQ(ExitSuccess, subproc->Finish());
+   ASSERT_EQ(1u, subprocs_.finished_.size());
+ }
+diff --git a/src/tokenpool-gnu-make.cc b/src/tokenpool-gnu-make.cc
+index a8f9b7139d..396bb7d874 100644
+--- a/src/tokenpool-gnu-make.cc
++++ b/src/tokenpool-gnu-make.cc
+@@ -33,6 +33,7 @@ struct GNUmakeTokenPool : public TokenPool {
+   virtual void Reserve();
+   virtual void Release();
+   virtual void Clear();
++  virtual int GetMonitorFd();
+ 
+   bool Setup();
+ 
+@@ -201,6 +202,10 @@ void GNUmakeTokenPool::Clear() {
+     Return();
+ }
+ 
++int GNUmakeTokenPool::GetMonitorFd() {
++  return(rfd_);
++}
++
+ struct TokenPool *TokenPool::Get(void) {
+   GNUmakeTokenPool *tokenpool = new GNUmakeTokenPool;
+   if (tokenpool->Setup())
+diff --git a/src/tokenpool.h b/src/tokenpool.h
+index f560b1083b..301e1998ee 100644
+--- a/src/tokenpool.h
++++ b/src/tokenpool.h
+@@ -21,6 +21,12 @@ struct TokenPool {
+   virtual void Release() = 0;
+   virtual void Clear() = 0;
+ 
++#ifdef _WIN32
++  // @TODO
++#else
++  virtual int GetMonitorFd() = 0;
++#endif
++
+   // returns NULL if token pool is not available
+   static struct TokenPool *Get(void);
+ };
+
+From d09f3d77821b3b1fdf09fc0ef8e814907675eafb Mon Sep 17 00:00:00 2001
+From: Stefan Becker <chemobejk@gmail.com>
+Date: Sun, 12 Nov 2017 16:58:55 +0200
+Subject: [PATCH 03/11] Ignore jobserver when -jN is forced on command line
+
+This emulates the behaviour of GNU make.
+
+- add parallelism_from_cmdline flag to build configuration
+- set the flag when -jN is given on command line
+- pass the flag to TokenPool::Get()
+- GNUmakeTokenPool::Setup()
+  * prints a warning when the flag is true and jobserver was detected
+  * returns false, i.e. jobserver will be ignored
+- ignore config.parallelism in CanRunMore() when we have a valid
+  TokenPool, because it gets always initialized to a default when not
+  given on the command line
+---
+ src/build.cc              | 10 ++++++----
+ src/build.h               |  4 +++-
+ src/ninja.cc              |  1 +
+ src/tokenpool-gnu-make.cc | 34 +++++++++++++++++++---------------
+ src/tokenpool-none.cc     |  4 ++--
+ src/tokenpool.h           |  4 ++--
+ 6 files changed, 33 insertions(+), 24 deletions(-)
+
+diff --git a/src/build.cc b/src/build.cc
+index a25c349050..406a84ec39 100644
+--- a/src/build.cc
++++ b/src/build.cc
+@@ -470,7 +470,7 @@ struct RealCommandRunner : public CommandRunner {
+ };
+ 
+ RealCommandRunner::RealCommandRunner(const BuildConfig& config) : config_(config) {
+-  tokens_ = TokenPool::Get();
++  tokens_ = TokenPool::Get(config_.parallelism_from_cmdline);
+ }
+ 
+ RealCommandRunner::~RealCommandRunner() {
+@@ -492,9 +492,11 @@ void RealCommandRunner::Abort() {
+ }
+ 
+ bool RealCommandRunner::CanRunMore() const {
+-  size_t subproc_number =
+-      subprocs_.running_.size() + subprocs_.finished_.size();
+-  return (int)subproc_number < config_.parallelism
++  bool parallelism_limit_not_reached =
++    tokens_ || // ignore config_.parallelism
++    ((int) (subprocs_.running_.size() +
++            subprocs_.finished_.size()) < config_.parallelism);
++  return parallelism_limit_not_reached
+     && (subprocs_.running_.empty() ||
+         (config_.max_load_average <= 0.0f ||
+          GetLoadAverage() < config_.max_load_average));
+diff --git a/src/build.h b/src/build.h
+index 35c7b97d12..dfde576573 100644
+--- a/src/build.h
++++ b/src/build.h
+@@ -159,7 +159,8 @@ struct CommandRunner {
+ 
+ /// Options (e.g. verbosity, parallelism) passed to a build.
+ struct BuildConfig {
+-  BuildConfig() : verbosity(NORMAL), dry_run(false), parallelism(1),
++  BuildConfig() : verbosity(NORMAL), dry_run(false),
++                  parallelism(1), parallelism_from_cmdline(false),
+                   failures_allowed(1), max_load_average(-0.0f) {}
+ 
+   enum Verbosity {
+@@ -171,6 +172,7 @@ struct BuildConfig {
+   Verbosity verbosity;
+   bool dry_run;
+   int parallelism;
++  bool parallelism_from_cmdline;
+   int failures_allowed;
+   /// The maximum load average we must not exceed. A negative value
+   /// means that we do not have any limit.
+diff --git a/src/ninja.cc b/src/ninja.cc
+index df39ba92d1..d904c56c4e 100644
+--- a/src/ninja.cc
++++ b/src/ninja.cc
+@@ -1447,6 +1447,7 @@ int ReadFlags(int* argc, char*** argv,
+         // We want to run N jobs in parallel. For N = 0, INT_MAX
+         // is close enough to infinite for most sane builds.
+         config->parallelism = value > 0 ? value : INT_MAX;
++        config->parallelism_from_cmdline = true;
+         deferGuessParallelism.needGuess = false;
+         break;
+       }
+diff --git a/src/tokenpool-gnu-make.cc b/src/tokenpool-gnu-make.cc
+index 396bb7d874..af4be05a31 100644
+--- a/src/tokenpool-gnu-make.cc
++++ b/src/tokenpool-gnu-make.cc
+@@ -1,4 +1,4 @@
+-// Copyright 2016 Google Inc. All Rights Reserved.
++// Copyright 2016-2017 Google Inc. All Rights Reserved.
+ //
+ // Licensed under the Apache License, Version 2.0 (the "License");
+ // you may not use this file except in compliance with the License.
+@@ -35,7 +35,7 @@ struct GNUmakeTokenPool : public TokenPool {
+   virtual void Clear();
+   virtual int GetMonitorFd();
+ 
+-  bool Setup();
++  bool Setup(bool ignore);
+ 
+  private:
+   int available_;
+@@ -100,7 +100,7 @@ bool GNUmakeTokenPool::SetAlarmHandler() {
+   }
+ }
+ 
+-bool GNUmakeTokenPool::Setup() {
++bool GNUmakeTokenPool::Setup(bool ignore) {
+   const char *value = getenv("MAKEFLAGS");
+   if (value) {
+     // GNU make <= 4.1
+@@ -109,16 +109,20 @@ bool GNUmakeTokenPool::Setup() {
+     if (!jobserver)
+       jobserver = strstr(value, "--jobserver-auth=");
+     if (jobserver) {
+-      int rfd = -1;
+-      int wfd = -1;
+-      if ((sscanf(jobserver, "%*[^=]=%d,%d", &rfd, &wfd) == 2) &&
+-          CheckFd(rfd) &&
+-          CheckFd(wfd) &&
+-          SetAlarmHandler()) {
+-        printf("ninja: using GNU make jobserver.\n");
+-        rfd_ = rfd;
+-        wfd_ = wfd;
+-        return true;
++      if (ignore) {
++        printf("ninja: warning: -jN forced on command line; ignoring GNU make jobserver.\n");
++      } else {
++        int rfd = -1;
++        int wfd = -1;
++        if ((sscanf(jobserver, "%*[^=]=%d,%d", &rfd, &wfd) == 2) &&
++            CheckFd(rfd) &&
++            CheckFd(wfd) &&
++            SetAlarmHandler()) {
++          printf("ninja: using GNU make jobserver.\n");
++          rfd_ = rfd;
++          wfd_ = wfd;
++          return true;
++        }
+       }
+     }
+   }
+@@ -206,9 +210,9 @@ int GNUmakeTokenPool::GetMonitorFd() {
+   return(rfd_);
+ }
+ 
+-struct TokenPool *TokenPool::Get(void) {
++struct TokenPool *TokenPool::Get(bool ignore) {
+   GNUmakeTokenPool *tokenpool = new GNUmakeTokenPool;
+-  if (tokenpool->Setup())
++  if (tokenpool->Setup(ignore))
+     return tokenpool;
+   else
+     delete tokenpool;
+diff --git a/src/tokenpool-none.cc b/src/tokenpool-none.cc
+index 602b3316f5..199b22264b 100644
+--- a/src/tokenpool-none.cc
++++ b/src/tokenpool-none.cc
+@@ -1,4 +1,4 @@
+-// Copyright 2016 Google Inc. All Rights Reserved.
++// Copyright 2016-2017 Google Inc. All Rights Reserved.
+ //
+ // Licensed under the Apache License, Version 2.0 (the "License");
+ // you may not use this file except in compliance with the License.
+@@ -22,6 +22,6 @@
+ #include <stdlib.h>
+ 
+ // No-op TokenPool implementation
+-struct TokenPool *TokenPool::Get(void) {
++struct TokenPool *TokenPool::Get(bool ignore) {
+   return NULL;
+ }
+diff --git a/src/tokenpool.h b/src/tokenpool.h
+index 301e1998ee..878a0933c2 100644
+--- a/src/tokenpool.h
++++ b/src/tokenpool.h
+@@ -1,4 +1,4 @@
+-// Copyright 2016 Google Inc. All Rights Reserved.
++// Copyright 2016-2017 Google Inc. All Rights Reserved.
+ //
+ // Licensed under the Apache License, Version 2.0 (the "License");
+ // you may not use this file except in compliance with the License.
+@@ -28,5 +28,5 @@ struct TokenPool {
+ #endif
+ 
+   // returns NULL if token pool is not available
+-  static struct TokenPool *Get(void);
++  static struct TokenPool *Get(bool ignore);
+ };
+
+From dfe4ca753caee65bf9041e2b4e883dfa172a5c6a Mon Sep 17 00:00:00 2001
+From: Stefan Becker <chemobejk@gmail.com>
+Date: Sun, 12 Nov 2017 18:04:12 +0200
+Subject: [PATCH 04/11] Honor -lN from MAKEFLAGS
+
+This emulates the behaviour of GNU make.
+
+- build: make a copy of max_load_average and pass it to TokenPool.
+- GNUmakeTokenPool: if we detect a jobserver and a valid -lN argument in
+  MAKEFLAGS then set max_load_average to N.
+---
+ src/build.cc              | 10 +++++++---
+ src/tokenpool-gnu-make.cc | 19 +++++++++++++++----
+ src/tokenpool-none.cc     |  2 +-
+ src/tokenpool.h           |  2 +-
+ 4 files changed, 24 insertions(+), 9 deletions(-)
+
+diff --git a/src/build.cc b/src/build.cc
+index 406a84ec39..9e6272d035 100644
+--- a/src/build.cc
++++ b/src/build.cc
+@@ -464,13 +464,17 @@ struct RealCommandRunner : public CommandRunner {
+   virtual void Abort();
+ 
+   const BuildConfig& config_;
++  // copy of config_.max_load_average; can be modified by TokenPool setup
++  double max_load_average_;
+   SubprocessSet subprocs_;
+   TokenPool *tokens_;
+   map<const Subprocess*, Edge*> subproc_to_edge_;
+ };
+ 
+ RealCommandRunner::RealCommandRunner(const BuildConfig& config) : config_(config) {
+-  tokens_ = TokenPool::Get(config_.parallelism_from_cmdline);
++  max_load_average_ = config.max_load_average;
++  tokens_ = TokenPool::Get(config_.parallelism_from_cmdline,
++                           max_load_average_);
+ }
+ 
+ RealCommandRunner::~RealCommandRunner() {
+@@ -498,8 +502,8 @@ bool RealCommandRunner::CanRunMore() const {
+             subprocs_.finished_.size()) < config_.parallelism);
+   return parallelism_limit_not_reached
+     && (subprocs_.running_.empty() ||
+-        (config_.max_load_average <= 0.0f ||
+-         GetLoadAverage() < config_.max_load_average));
++        (max_load_average_ <= 0.0f ||
++         GetLoadAverage() < max_load_average_));
+ }
+ 
+ bool RealCommandRunner::AcquireToken() {
+diff --git a/src/tokenpool-gnu-make.cc b/src/tokenpool-gnu-make.cc
+index af4be05a31..fb654c4d88 100644
+--- a/src/tokenpool-gnu-make.cc
++++ b/src/tokenpool-gnu-make.cc
+@@ -35,7 +35,7 @@ struct GNUmakeTokenPool : public TokenPool {
+   virtual void Clear();
+   virtual int GetMonitorFd();
+ 
+-  bool Setup(bool ignore);
++  bool Setup(bool ignore, double& max_load_average);
+ 
+  private:
+   int available_;
+@@ -100,7 +100,7 @@ bool GNUmakeTokenPool::SetAlarmHandler() {
+   }
+ }
+ 
+-bool GNUmakeTokenPool::Setup(bool ignore) {
++bool GNUmakeTokenPool::Setup(bool ignore, double& max_load_average) {
+   const char *value = getenv("MAKEFLAGS");
+   if (value) {
+     // GNU make <= 4.1
+@@ -118,9 +118,20 @@ bool GNUmakeTokenPool::Setup(bool ignore) {
+             CheckFd(rfd) &&
+             CheckFd(wfd) &&
+             SetAlarmHandler()) {
++          const char *l_arg = strstr(value, " -l");
++          int load_limit = -1;
++
+           printf("ninja: using GNU make jobserver.\n");
+           rfd_ = rfd;
+           wfd_ = wfd;
++
++          // translate GNU make -lN to ninja -lN
++          if (l_arg &&
++              (sscanf(l_arg + 3, "%d ", &load_limit) == 1) &&
++              (load_limit > 0)) {
++            max_load_average = load_limit;
++          }
++
+           return true;
+         }
+       }
+@@ -210,9 +221,9 @@ int GNUmakeTokenPool::GetMonitorFd() {
+   return(rfd_);
+ }
+ 
+-struct TokenPool *TokenPool::Get(bool ignore) {
++struct TokenPool *TokenPool::Get(bool ignore, double& max_load_average) {
+   GNUmakeTokenPool *tokenpool = new GNUmakeTokenPool;
+-  if (tokenpool->Setup(ignore))
++  if (tokenpool->Setup(ignore, max_load_average))
+     return tokenpool;
+   else
+     delete tokenpool;
+diff --git a/src/tokenpool-none.cc b/src/tokenpool-none.cc
+index 199b22264b..e8e25426c3 100644
+--- a/src/tokenpool-none.cc
++++ b/src/tokenpool-none.cc
+@@ -22,6 +22,6 @@
+ #include <stdlib.h>
+ 
+ // No-op TokenPool implementation
+-struct TokenPool *TokenPool::Get(bool ignore) {
++struct TokenPool *TokenPool::Get(bool ignore, double& max_load_average) {
+   return NULL;
+ }
+diff --git a/src/tokenpool.h b/src/tokenpool.h
+index 878a0933c2..f9e8cc2ee0 100644
+--- a/src/tokenpool.h
++++ b/src/tokenpool.h
+@@ -28,5 +28,5 @@ struct TokenPool {
+ #endif
+ 
+   // returns NULL if token pool is not available
+-  static struct TokenPool *Get(bool ignore);
++  static struct TokenPool *Get(bool ignore, double& max_load_average);
+ };
+
+From 1c10047fc6a3269ba42839da19361e09cbc06ff0 Mon Sep 17 00:00:00 2001
+From: Stefan Becker <chemobejk@gmail.com>
+Date: Wed, 6 Dec 2017 22:14:21 +0200
+Subject: [PATCH 05/11] Use LinePrinter for TokenPool messages
+
+- replace printf() with calls to LinePrinter
+- print GNU make jobserver message only when verbose build is requested
+---
+ src/build.cc              |  1 +
+ src/tokenpool-gnu-make.cc | 22 ++++++++++++++++------
+ src/tokenpool-none.cc     |  4 +++-
+ src/tokenpool.h           |  4 +++-
+ 4 files changed, 23 insertions(+), 8 deletions(-)
+
+diff --git a/src/build.cc b/src/build.cc
+index 9e6272d035..662e4bd7be 100644
+--- a/src/build.cc
++++ b/src/build.cc
+@@ -474,6 +474,7 @@ struct RealCommandRunner : public CommandRunner {
+ RealCommandRunner::RealCommandRunner(const BuildConfig& config) : config_(config) {
+   max_load_average_ = config.max_load_average;
+   tokens_ = TokenPool::Get(config_.parallelism_from_cmdline,
++                           config_.verbosity == BuildConfig::VERBOSE,
+                            max_load_average_);
+ }
+ 
+diff --git a/src/tokenpool-gnu-make.cc b/src/tokenpool-gnu-make.cc
+index fb654c4d88..b0d3e6ebc4 100644
+--- a/src/tokenpool-gnu-make.cc
++++ b/src/tokenpool-gnu-make.cc
+@@ -23,6 +23,8 @@
+ #include <string.h>
+ #include <stdlib.h>
+ 
++#include "line_printer.h"
++
+ // TokenPool implementation for GNU make jobserver
+ // (http://make.mad-scientist.net/papers/jobserver-implementation/)
+ struct GNUmakeTokenPool : public TokenPool {
+@@ -35,7 +37,7 @@ struct GNUmakeTokenPool : public TokenPool {
+   virtual void Clear();
+   virtual int GetMonitorFd();
+ 
+-  bool Setup(bool ignore, double& max_load_average);
++  bool Setup(bool ignore, bool verbose, double& max_load_average);
+ 
+  private:
+   int available_;
+@@ -100,7 +102,9 @@ bool GNUmakeTokenPool::SetAlarmHandler() {
+   }
+ }
+ 
+-bool GNUmakeTokenPool::Setup(bool ignore, double& max_load_average) {
++bool GNUmakeTokenPool::Setup(bool ignore,
++                             bool verbose,
++                             double& max_load_average) {
+   const char *value = getenv("MAKEFLAGS");
+   if (value) {
+     // GNU make <= 4.1
+@@ -109,8 +113,10 @@ bool GNUmakeTokenPool::Setup(bool ignore, double& max_load_average) {
+     if (!jobserver)
+       jobserver = strstr(value, "--jobserver-auth=");
+     if (jobserver) {
++      LinePrinter printer;
++
+       if (ignore) {
+-        printf("ninja: warning: -jN forced on command line; ignoring GNU make jobserver.\n");
++        printer.PrintOnNewLine("ninja: warning: -jN forced on command line; ignoring GNU make jobserver.\n");
+       } else {
+         int rfd = -1;
+         int wfd = -1;
+@@ -121,7 +127,9 @@ bool GNUmakeTokenPool::Setup(bool ignore, double& max_load_average) {
+           const char *l_arg = strstr(value, " -l");
+           int load_limit = -1;
+ 
+-          printf("ninja: using GNU make jobserver.\n");
++          if (verbose) {
++            printer.PrintOnNewLine("ninja: using GNU make jobserver.\n");
++          }
+           rfd_ = rfd;
+           wfd_ = wfd;
+ 
+@@ -221,9 +229,11 @@ int GNUmakeTokenPool::GetMonitorFd() {
+   return(rfd_);
+ }
+ 
+-struct TokenPool *TokenPool::Get(bool ignore, double& max_load_average) {
++struct TokenPool *TokenPool::Get(bool ignore,
++                                 bool verbose,
++                                 double& max_load_average) {
+   GNUmakeTokenPool *tokenpool = new GNUmakeTokenPool;
+-  if (tokenpool->Setup(ignore, max_load_average))
++  if (tokenpool->Setup(ignore, verbose, max_load_average))
+     return tokenpool;
+   else
+     delete tokenpool;
+diff --git a/src/tokenpool-none.cc b/src/tokenpool-none.cc
+index e8e25426c3..1c1c499c8d 100644
+--- a/src/tokenpool-none.cc
++++ b/src/tokenpool-none.cc
+@@ -22,6 +22,8 @@
+ #include <stdlib.h>
+ 
+ // No-op TokenPool implementation
+-struct TokenPool *TokenPool::Get(bool ignore, double& max_load_average) {
++struct TokenPool *TokenPool::Get(bool ignore,
++                                 bool verbose,
++                                 double& max_load_average) {
+   return NULL;
+ }
+diff --git a/src/tokenpool.h b/src/tokenpool.h
+index f9e8cc2ee0..4bf477f20c 100644
+--- a/src/tokenpool.h
++++ b/src/tokenpool.h
+@@ -28,5 +28,7 @@ struct TokenPool {
+ #endif
+ 
+   // returns NULL if token pool is not available
+-  static struct TokenPool *Get(bool ignore, double& max_load_average);
++  static struct TokenPool *Get(bool ignore,
++                               bool verbose,
++                               double& max_load_average);
+ };
+
+From fdbf68416e3574add3bffd0b637d0694fbaba320 Mon Sep 17 00:00:00 2001
+From: Stefan Becker <chemobejk@gmail.com>
+Date: Sat, 7 Apr 2018 17:11:21 +0300
+Subject: [PATCH 06/11] Prepare PR for merging
+
+- fix Windows build error in no-op TokenPool implementation
+- improve Acquire() to block for a maximum of 100ms
+- address review comments
+---
+ src/build.h               |  2 ++
+ src/tokenpool-gnu-make.cc | 53 +++++++++++++++++++++++++++++++++------
+ src/tokenpool-none.cc     |  7 +-----
+ 3 files changed, 49 insertions(+), 13 deletions(-)
+
+diff --git a/src/build.h b/src/build.h
+index dfde576573..66ddefb888 100644
+--- a/src/build.h
++++ b/src/build.h
+@@ -151,6 +151,8 @@ struct CommandRunner {
+     bool success() const { return status == ExitSuccess; }
+   };
+   /// Wait for a command to complete, or return false if interrupted.
++  /// If more_ready is true then the optional TokenPool is monitored too
++  /// and we return when a token becomes available.
+   virtual bool WaitForCommand(Result* result, bool more_ready) = 0;
+ 
+   virtual std::vector<Edge*> GetActiveEdges() { return std::vector<Edge*>(); }
+diff --git a/src/tokenpool-gnu-make.cc b/src/tokenpool-gnu-make.cc
+index b0d3e6ebc4..4132bb06d9 100644
+--- a/src/tokenpool-gnu-make.cc
++++ b/src/tokenpool-gnu-make.cc
+@@ -1,4 +1,4 @@
+-// Copyright 2016-2017 Google Inc. All Rights Reserved.
++// Copyright 2016-2018 Google Inc. All Rights Reserved.
+ //
+ // Licensed under the Apache License, Version 2.0 (the "License");
+ // you may not use this file except in compliance with the License.
+@@ -19,6 +19,7 @@
+ #include <poll.h>
+ #include <unistd.h>
+ #include <signal.h>
++#include <sys/time.h>
+ #include <stdio.h>
+ #include <string.h>
+ #include <stdlib.h>
+@@ -153,6 +154,15 @@ bool GNUmakeTokenPool::Acquire() {
+   if (available_ > 0)
+     return true;
+ 
++  // Please read
++  //
++  //   http://make.mad-scientist.net/papers/jobserver-implementation/
++  //
++  // for the reasoning behind the following code.
++  //
++  // Try to read one character from the pipe. Returns true on success.
++  //
++  // First check if read() would succeed without blocking.
+ #ifdef USE_PPOLL
+   pollfd pollfds[] = {{rfd_, POLLIN, 0}};
+   int ret = poll(pollfds, 1, 0);
+@@ -164,33 +174,62 @@ bool GNUmakeTokenPool::Acquire() {
+   int ret = select(rfd_ + 1, &set, NULL, NULL, &timeout);
+ #endif
+   if (ret > 0) {
++    // Handle potential race condition:
++    //  - the above check succeeded, i.e. read() should not block
++    //  - the character disappears before we call read()
++    //
++    // Create a duplicate of rfd_. The duplicate file descriptor dup_rfd_
++    // can safely be closed by signal handlers without affecting rfd_.
+     dup_rfd_ = dup(rfd_);
+ 
+     if (dup_rfd_ != -1) {
+       struct sigaction act, old_act;
+       int ret = 0;
+ 
++      // Temporarily replace SIGCHLD handler with our own
+       memset(&act, 0, sizeof(act));
+       act.sa_handler = CloseDupRfd;
+       if (sigaction(SIGCHLD, &act, &old_act) == 0) {
+-        char buf;
+-
+-        // block until token read, child exits or timeout
+-        alarm(1);
+-        ret = read(dup_rfd_, &buf, 1);
+-        alarm(0);
++        struct itimerval timeout;
++
++        // install a 100ms timeout that generates SIGALARM on expiration
++        memset(&timeout, 0, sizeof(timeout));
++        timeout.it_value.tv_usec = 100 * 1000; // [ms] -> [usec]
++        if (setitimer(ITIMER_REAL, &timeout, NULL) == 0) {
++          char buf;
++
++          // Now try to read() from dup_rfd_. Return values from read():
++          //
++          // 1. token read                               ->  1
++          // 2. pipe closed                              ->  0
++          // 3. alarm expires                            -> -1 (EINTR)
++          // 4. child exits                              -> -1 (EINTR)
++          // 5. alarm expired before entering read()     -> -1 (EBADF)
++          // 6. child exited before entering read()      -> -1 (EBADF)
++          // 7. child exited before handler is installed -> go to 1 - 3
++          ret = read(dup_rfd_, &buf, 1);
++
++          // disarm timer
++          memset(&timeout, 0, sizeof(timeout));
++          setitimer(ITIMER_REAL, &timeout, NULL);
++        }
+ 
+         sigaction(SIGCHLD, &old_act, NULL);
+       }
+ 
+       CloseDupRfd(0);
+ 
++      // Case 1 from above list
+       if (ret > 0) {
+         available_++;
+         return true;
+       }
+     }
+   }
++
++  // read() would block, i.e. no token available,
++  // cases 2-6 from above list or
++  // select() / poll() / dup() / sigaction() / setitimer() failed
+   return false;
+ }
+ 
+diff --git a/src/tokenpool-none.cc b/src/tokenpool-none.cc
+index 1c1c499c8d..4c592875b4 100644
+--- a/src/tokenpool-none.cc
++++ b/src/tokenpool-none.cc
+@@ -1,4 +1,4 @@
+-// Copyright 2016-2017 Google Inc. All Rights Reserved.
++// Copyright 2016-2018 Google Inc. All Rights Reserved.
+ //
+ // Licensed under the Apache License, Version 2.0 (the "License");
+ // you may not use this file except in compliance with the License.
+@@ -14,11 +14,6 @@
+ 
+ #include "tokenpool.h"
+ 
+-#include <fcntl.h>
+-#include <poll.h>
+-#include <unistd.h>
+-#include <stdio.h>
+-#include <string.h>
+ #include <stdlib.h>
+ 
+ // No-op TokenPool implementation
+
+From ec6220a0baf7d3a6eaf1a2b75bf8960ddfe24c2f Mon Sep 17 00:00:00 2001
+From: Stefan Becker <chemobejk@gmail.com>
+Date: Fri, 25 May 2018 00:17:07 +0300
+Subject: [PATCH 07/11] Add tests for TokenPool
+
+- TokenPool setup
+- GetMonitorFd() API
+- implicit token and tokens in jobserver pipe
+- Acquire() / Reserve() / Release() protocol
+- Clear() API
+---
+ configure.py          |   1 +
+ src/tokenpool_test.cc | 198 ++++++++++++++++++++++++++++++++++++++++++
+ 2 files changed, 199 insertions(+)
+ create mode 100644 src/tokenpool_test.cc
+
+diff --git a/configure.py b/configure.py
+index db3492c93c..dc8a0066b7 100755
+--- a/configure.py
++++ b/configure.py
+@@ -590,6 +590,7 @@ def has_re2c():
+              'string_piece_util_test',
+              'subprocess_test',
+              'test',
++             'tokenpool_test',
+              'util_test']:
+     objs += cxx(name, variables=cxxvariables)
+ if platform.is_windows():
+diff --git a/src/tokenpool_test.cc b/src/tokenpool_test.cc
+new file mode 100644
+index 0000000000..6c89064ca4
+--- /dev/null
++++ b/src/tokenpool_test.cc
+@@ -0,0 +1,198 @@
++// Copyright 2018 Google Inc. All Rights Reserved.
++//
++// Licensed under the Apache License, Version 2.0 (the "License");
++// you may not use this file except in compliance with the License.
++// You may obtain a copy of the License at
++//
++//     http://www.apache.org/licenses/LICENSE-2.0
++//
++// Unless required by applicable law or agreed to in writing, software
++// distributed under the License is distributed on an "AS IS" BASIS,
++// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
++// See the License for the specific language governing permissions and
++// limitations under the License.
++
++#include "tokenpool.h"
++
++#include "test.h"
++
++#ifndef _WIN32
++#include <stdio.h>
++#include <stdlib.h>
++#include <unistd.h>
++
++#define ENVIRONMENT_CLEAR() unsetenv("MAKEFLAGS")
++#define ENVIRONMENT_INIT(v) setenv("MAKEFLAGS", v, true);
++#endif
++
++namespace {
++
++const double kLoadAverageDefault = -1.23456789;
++
++struct TokenPoolTest : public testing::Test {
++  double load_avg_;
++  TokenPool *tokens_;
++#ifndef _WIN32
++  char buf_[1024];
++  int fds_[2];
++#endif
++
++  virtual void SetUp() {
++    load_avg_ = kLoadAverageDefault;
++    tokens_ = NULL;
++#ifndef _WIN32
++    ENVIRONMENT_CLEAR();
++    if (pipe(fds_) < 0)
++      ASSERT_TRUE(false);
++#endif
++  }
++
++  void CreatePool(const char *format, bool ignore_jobserver) {
++#ifndef _WIN32
++    if (format) {
++      sprintf(buf_, format, fds_[0], fds_[1]);
++      ENVIRONMENT_INIT(buf_);
++    }
++#endif
++    tokens_ = TokenPool::Get(ignore_jobserver, false, load_avg_);
++  }
++
++  void CreateDefaultPool() {
++    CreatePool("foo --jobserver-auth=%d,%d bar", false);
++  }
++
++  virtual void TearDown() {
++    if (tokens_)
++      delete tokens_;
++#ifndef _WIN32
++    close(fds_[0]);
++    close(fds_[1]);
++    ENVIRONMENT_CLEAR();
++#endif
++  }
++};
++
++} // anonymous namespace
++
++// verifies none implementation
++TEST_F(TokenPoolTest, NoTokenPool) {
++  CreatePool(NULL, false);
++
++  EXPECT_EQ(NULL, tokens_);
++  EXPECT_EQ(kLoadAverageDefault, load_avg_);
++}
++
++#ifndef _WIN32
++TEST_F(TokenPoolTest, SuccessfulOldSetup) {
++  // GNUmake <= 4.1
++  CreatePool("foo --jobserver-fds=%d,%d bar", false);
++
++  EXPECT_NE(NULL, tokens_);
++  EXPECT_EQ(kLoadAverageDefault, load_avg_);
++}
++
++TEST_F(TokenPoolTest, SuccessfulNewSetup) {
++  // GNUmake => 4.2
++  CreateDefaultPool();
++
++  EXPECT_NE(NULL, tokens_);
++  EXPECT_EQ(kLoadAverageDefault, load_avg_);
++}
++
++TEST_F(TokenPoolTest, IgnoreWithJN) {
++  CreatePool("foo --jobserver-auth=%d,%d bar", true);
++
++  EXPECT_EQ(NULL, tokens_);
++  EXPECT_EQ(kLoadAverageDefault, load_avg_);
++}
++
++TEST_F(TokenPoolTest, HonorLN) {
++  CreatePool("foo -l9 --jobserver-auth=%d,%d bar", false);
++
++  EXPECT_NE(NULL, tokens_);
++  EXPECT_EQ(9.0, load_avg_);
++}
++
++TEST_F(TokenPoolTest, MonitorFD) {
++  CreateDefaultPool();
++
++  ASSERT_NE(NULL, tokens_);
++  EXPECT_EQ(kLoadAverageDefault, load_avg_);
++
++  EXPECT_EQ(fds_[0], tokens_->GetMonitorFd());
++}
++
++TEST_F(TokenPoolTest, ImplicitToken) {
++  CreateDefaultPool();
++
++  ASSERT_NE(NULL, tokens_);
++  EXPECT_EQ(kLoadAverageDefault, load_avg_);
++
++  EXPECT_TRUE(tokens_->Acquire());
++  tokens_->Reserve();
++  EXPECT_FALSE(tokens_->Acquire());
++  tokens_->Release();
++  EXPECT_TRUE(tokens_->Acquire());
++}
++
++TEST_F(TokenPoolTest, TwoTokens) {
++  CreateDefaultPool();
++
++  ASSERT_NE(NULL, tokens_);
++  EXPECT_EQ(kLoadAverageDefault, load_avg_);
++
++  // implicit token
++  EXPECT_TRUE(tokens_->Acquire());
++  tokens_->Reserve();
++  EXPECT_FALSE(tokens_->Acquire());
++
++  // jobserver offers 2nd token
++  ASSERT_EQ(1u, write(fds_[1], "T", 1));
++  EXPECT_TRUE(tokens_->Acquire());
++  tokens_->Reserve();
++  EXPECT_FALSE(tokens_->Acquire());
++
++  // release 2nd token
++  tokens_->Release();
++  EXPECT_TRUE(tokens_->Acquire());
++
++  // release implict token - must return 2nd token back to jobserver
++  tokens_->Release();
++  EXPECT_TRUE(tokens_->Acquire());
++
++  // there must be one token in the pipe
++  EXPECT_EQ(1u, read(fds_[0], buf_, sizeof(buf_)));
++
++  // implicit token
++  EXPECT_TRUE(tokens_->Acquire());
++}
++
++TEST_F(TokenPoolTest, Clear) {
++  CreateDefaultPool();
++
++  ASSERT_NE(NULL, tokens_);
++  EXPECT_EQ(kLoadAverageDefault, load_avg_);
++
++  // implicit token
++  EXPECT_TRUE(tokens_->Acquire());
++  tokens_->Reserve();
++  EXPECT_FALSE(tokens_->Acquire());
++
++  // jobserver offers 2nd & 3rd token
++  ASSERT_EQ(2u, write(fds_[1], "TT", 2));
++  EXPECT_TRUE(tokens_->Acquire());
++  tokens_->Reserve();
++  EXPECT_TRUE(tokens_->Acquire());
++  tokens_->Reserve();
++  EXPECT_FALSE(tokens_->Acquire());
++
++  tokens_->Clear();
++  EXPECT_TRUE(tokens_->Acquire());
++
++  // there must be two tokens in the pipe
++  EXPECT_EQ(2u, read(fds_[0], buf_, sizeof(buf_)));
++
++  // implicit token
++  EXPECT_TRUE(tokens_->Acquire());
++}
++#endif
+
+From e59d8858327126d1593fd0b8e607975a79072e92 Mon Sep 17 00:00:00 2001
+From: Stefan Becker <chemobejk@gmail.com>
+Date: Thu, 24 May 2018 18:52:45 +0300
+Subject: [PATCH 08/11] Add tests for subprocess module
+
+- add TokenPoolTest stub to provide TokenPool::GetMonitorFd()
+- add two tests
+  * both tests set up a dummy GNUmake jobserver pipe
+  * both tests call DoWork() with TokenPoolTest
+  * test 1: verify that DoWork() detects when a token is available
+  * test 2: verify that DoWork() works as before without a token
+- the tests are not compiled in under Windows
+---
+ src/subprocess_test.cc | 76 ++++++++++++++++++++++++++++++++++++++++++
+ 1 file changed, 76 insertions(+)
+
+diff --git a/src/subprocess_test.cc b/src/subprocess_test.cc
+index 4bc8083e26..6264c8bf11 100644
+--- a/src/subprocess_test.cc
++++ b/src/subprocess_test.cc
+@@ -13,6 +13,7 @@
+ // limitations under the License.
+ 
+ #include "subprocess.h"
++#include "tokenpool.h"
+ 
+ #include "test.h"
+ 
+@@ -34,8 +35,23 @@ const char* kSimpleCommand = "cmd /c dir \\";
+ const char* kSimpleCommand = "ls /";
+ #endif
+ 
++struct TokenPoolTest : public TokenPool {
++  bool Acquire()     { return false; }
++  void Reserve()     {}
++  void Release()     {}
++  void Clear()       {}
++
++#ifdef _WIN32
++  // @TODO
++#else
++  int _fd;
++  int GetMonitorFd() { return _fd; }
++#endif
++};
++
+ struct SubprocessTest : public testing::Test {
+   SubprocessSet subprocs_;
++  TokenPoolTest tokens_;
+ };
+ 
+ }  // anonymous namespace
+@@ -280,3 +296,63 @@ TEST_F(SubprocessTest, ReadStdin) {
+   ASSERT_EQ(1u, subprocs_.finished_.size());
+ }
+ #endif  // _WIN32
++
++// @TODO: remove once TokenPool implementation for Windows is available
++#ifndef _WIN32
++TEST_F(SubprocessTest, TokenAvailable) {
++  Subprocess* subproc = subprocs_.Add(kSimpleCommand);
++  ASSERT_NE((Subprocess *) 0, subproc);
++
++  // simulate GNUmake jobserver pipe with 1 token
++  int fds[2];
++  ASSERT_EQ(0u, pipe(fds));
++  tokens_._fd = fds[0];
++  ASSERT_EQ(1u, write(fds[1], "T", 1));
++
++  subprocs_.ResetTokenAvailable();
++  subprocs_.DoWork(&tokens_);
++
++  EXPECT_TRUE(subprocs_.IsTokenAvailable());
++  EXPECT_EQ(0u, subprocs_.finished_.size());
++
++  // remove token to let DoWork() wait for command again
++  char token;
++  ASSERT_EQ(1u, read(fds[0], &token, 1));
++
++  while (!subproc->Done()) {
++    subprocs_.DoWork(&tokens_);
++  }
++
++  close(fds[1]);
++  close(fds[0]);
++
++  EXPECT_EQ(ExitSuccess, subproc->Finish());
++  EXPECT_NE("", subproc->GetOutput());
++
++  EXPECT_EQ(1u, subprocs_.finished_.size());
++}
++
++TEST_F(SubprocessTest, TokenNotAvailable) {
++  Subprocess* subproc = subprocs_.Add(kSimpleCommand);
++  ASSERT_NE((Subprocess *) 0, subproc);
++
++  // simulate GNUmake jobserver pipe with 0 tokens
++  int fds[2];
++  ASSERT_EQ(0u, pipe(fds));
++  tokens_._fd = fds[0];
++
++  subprocs_.ResetTokenAvailable();
++  while (!subproc->Done()) {
++    subprocs_.DoWork(&tokens_);
++  }
++
++  close(fds[1]);
++  close(fds[0]);
++
++  EXPECT_FALSE(subprocs_.IsTokenAvailable());
++  EXPECT_EQ(ExitSuccess, subproc->Finish());
++  EXPECT_NE("", subproc->GetOutput());
++
++  EXPECT_EQ(1u, subprocs_.finished_.size());
++}
++#endif  // _WIN32
+
+From 0145e2d4db64ea6c21aeb371928e4071f65164eb Mon Sep 17 00:00:00 2001
+From: Stefan Becker <chemobejk@gmail.com>
+Date: Sat, 26 May 2018 23:17:51 +0300
+Subject: [PATCH 09/11] Add tests for build module
+
+Add tests that verify the token functionality of the builder main loop.
+We replace the default fake command runner with a special version where
+the tests can control each call to AcquireToken(), CanRunMore() and
+WaitForCommand().
+---
+ src/build_test.cc | 364 ++++++++++++++++++++++++++++++++++++++++++++++
+ 1 file changed, 364 insertions(+)
+
+diff --git a/src/build_test.cc b/src/build_test.cc
+index 7a5ff4015a..dd41dfbe1d 100644
+--- a/src/build_test.cc
++++ b/src/build_test.cc
+@@ -15,6 +15,7 @@
+ #include "build.h"
+ 
+ #include <assert.h>
++#include <stdarg.h>
+ 
+ #include "build_log.h"
+ #include "deps_log.h"
+@@ -3990,3 +3991,366 @@ TEST_F(BuildTest, ValidationWithCircularDependency) {
+   EXPECT_FALSE(builder_.AddTarget("out", &err));
+   EXPECT_EQ("dependency cycle: validate -> validate_in -> validate", err);
  }
 +
 +/// The token tests are concerned with the main loop functionality when
@@ -706,6 +2177,16 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
 +  }
 +}
 +
++TEST_F(BuildTokenTest, CompleteNoWork) {
++  // plan should not execute anything
++  string err;
++
++  EXPECT_TRUE(builder_.Build(&err));
++  EXPECT_EQ("", err);
++
++  EXPECT_EQ(0u, token_command_runner_.commands_ran_.size());
++}
++
 +TEST_F(BuildTokenTest, DoNotAquireToken) {
 +  // plan should execute one command
 +  string err;
@@ -906,109 +2387,106 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
 +               token_command_runner_.commands_ran_[1] == "cat in1 > out1"));
 +  EXPECT_TRUE(token_command_runner_.commands_ran_[2] == "cat out1 out2 > out12");
 +}
---- a/src/exit_status.h
-+++ b/src/exit_status.h
-@@ -18,7 +18,8 @@
- enum ExitStatus {
-   ExitSuccess,
-   ExitFailure,
--  ExitInterrupted
-+  ExitTokenAvailable,
-+  ExitInterrupted,
- };
- 
- #endif  // NINJA_EXIT_STATUS_H_
---- a/src/ninja.cc
-+++ b/src/ninja.cc
-@@ -1289,6 +1289,7 @@ int ReadFlags(int* argc, char*** argv,
-         // We want to run N jobs in parallel. For N = 0, INT_MAX
-         // is close enough to infinite for most sane builds.
-         config->parallelism = value > 0 ? value : INT_MAX;
-+        config->parallelism_from_cmdline = true;
-         break;
-       }
-       case 'k': {
---- a/src/subprocess-posix.cc
-+++ b/src/subprocess-posix.cc
-@@ -13,6 +13,7 @@
- // limitations under the License.
- 
- #include "subprocess.h"
-+#include "tokenpool.h"
- 
- #include <sys/select.h>
- #include <assert.h>
-@@ -249,7 +250,7 @@ Subprocess *SubprocessSet::Add(const str
- }
- 
- #ifdef USE_PPOLL
--bool SubprocessSet::DoWork() {
-+bool SubprocessSet::DoWork(TokenPool* tokens) {
-   vector<pollfd> fds;
-   nfds_t nfds = 0;
- 
-@@ -263,6 +264,12 @@ bool SubprocessSet::DoWork() {
-     ++nfds;
-   }
- 
-+  if (tokens) {
-+    pollfd pfd = { tokens->GetMonitorFd(), POLLIN | POLLPRI, 0 };
-+    fds.push_back(pfd);
-+    ++nfds;
-+  }
-+
-   interrupted_ = 0;
-   int ret = ppoll(&fds.front(), nfds, NULL, &old_mask_);
-   if (ret == -1) {
-@@ -295,11 +302,20 @@ bool SubprocessSet::DoWork() {
-     ++i;
-   }
+
+From f016e5430c9123d34a73ea7ad28693b20ee59d6d Mon Sep 17 00:00:00 2001
+From: Stefan Becker <chemobejk@gmail.com>
+Date: Mon, 8 Oct 2018 17:47:50 +0300
+Subject: [PATCH 10/11] Add Win32 implementation for GNUmakeTokenPool
+
+GNU make uses a semaphore as jobserver protocol on Win32. See also
+
+   https://www.gnu.org/software/make/manual/html_node/Windows-Jobserver.html
+
+Usage is pretty simple and straightforward, i.e. WaitForSingleObject()
+to obtain a token and ReleaseSemaphore() to return it.
+
+Unfortunately subprocess-win32.cc uses an I/O completion port (IOCP).
+IOCPs aren't waitable objects, i.e. we can't use WaitForMultipleObjects()
+to wait on the IOCP and the token semaphore at the same time.
+
+Therefore GNUmakeTokenPoolWin32 creates a child thread that waits on the
+token semaphore and posts a dummy I/O completion status on the IOCP when
+it was able to obtain a token. That unblocks SubprocessSet::DoWork() and
+it can then check if a token became available or not.
+
+- split existing GNUmakeTokenPool into common and platform bits
+- add GNUmakeTokenPool interface
+- move the Posix bits to GNUmakeTokenPoolPosix
+- add the Win32 bits as GNUmakeTokenPoolWin32
+- move Setup() method up to TokenPool interface
+- update Subprocess & TokenPool tests accordingly
+---
+ configure.py                    |   8 +-
+ src/build.cc                    |  11 +-
+ src/subprocess-win32.cc         |   9 ++
+ src/subprocess_test.cc          |  34 ++++-
+ src/tokenpool-gnu-make-posix.cc | 203 +++++++++++++++++++++++++++
+ src/tokenpool-gnu-make-win32.cc | 237 ++++++++++++++++++++++++++++++++
+ src/tokenpool-gnu-make.cc       | 203 ++-------------------------
+ src/tokenpool-gnu-make.h        |  40 ++++++
+ src/tokenpool-none.cc           |   4 +-
+ src/tokenpool.h                 |  18 ++-
+ src/tokenpool_test.cc           | 113 ++++++++++++---
+ 11 files changed, 653 insertions(+), 227 deletions(-)
+ create mode 100644 src/tokenpool-gnu-make-posix.cc
+ create mode 100644 src/tokenpool-gnu-make-win32.cc
+ create mode 100644 src/tokenpool-gnu-make.h
+
+diff --git a/configure.py b/configure.py
+index dc8a0066b7..a239b90eef 100755
+--- a/configure.py
++++ b/configure.py
+@@ -517,12 +517,13 @@ def has_re2c():
+              'state',
+              'status',
+              'string_piece_util',
++             'tokenpool-gnu-make',
+              'util',
+              'version']:
+     objs += cxx(name, variables=cxxvariables)
+ if platform.is_windows():
+     for name in ['subprocess-win32',
+-                 'tokenpool-none',
++                 'tokenpool-gnu-make-win32',
+                  'includes_normalize-win32',
+                  'msvc_helper-win32',
+                  'msvc_helper_main-win32']:
+@@ -531,8 +532,9 @@ def has_re2c():
+         objs += cxx('minidump-win32', variables=cxxvariables)
+     objs += cc('getopt')
+ else:
+-    objs += cxx('subprocess-posix')
+-    objs += cxx('tokenpool-gnu-make')
++    for name in ['subprocess-posix',
++                 'tokenpool-gnu-make-posix']:
++        objs += cxx(name)
+ if platform.is_aix():
+     objs += cc('getopt')
+ if platform.is_msvc():
+diff --git a/src/build.cc b/src/build.cc
+index 662e4bd7be..20c3bdc2a0 100644
+--- a/src/build.cc
++++ b/src/build.cc
+@@ -473,9 +473,14 @@ struct RealCommandRunner : public CommandRunner {
  
-+  if (tokens) {
-+    pollfd *pfd = &fds[nfds - 1];
-+    if (pfd->fd >= 0) {
-+      assert(pfd->fd == tokens->GetMonitorFd());
-+      if (pfd->revents != 0)
-+        token_available_ = true;
+ RealCommandRunner::RealCommandRunner(const BuildConfig& config) : config_(config) {
+   max_load_average_ = config.max_load_average;
+-  tokens_ = TokenPool::Get(config_.parallelism_from_cmdline,
+-                           config_.verbosity == BuildConfig::VERBOSE,
+-                           max_load_average_);
++  if ((tokens_ = TokenPool::Get()) != NULL) {
++    if (!tokens_->Setup(config_.parallelism_from_cmdline,
++                        config_.verbosity == BuildConfig::VERBOSE,
++                        max_load_average_)) {
++      delete tokens_;
++      tokens_ = NULL;
 +    }
 +  }
-+
-   return IsInterrupted();
  }
  
- #else  // !defined(USE_PPOLL)
--bool SubprocessSet::DoWork() {
-+bool SubprocessSet::DoWork(TokenPool* tokens) {
-   fd_set set;
-   int nfds = 0;
-   FD_ZERO(&set);
-@@ -314,6 +330,13 @@ bool SubprocessSet::DoWork() {
-     }
-   }
- 
-+  if (tokens) {
-+    int fd = tokens->GetMonitorFd();
-+    FD_SET(fd, &set);
-+    if (nfds < fd+1)
-+      nfds = fd+1;
-+  }
-+
-   interrupted_ = 0;
-   int ret = pselect(nfds, &set, 0, 0, 0, &old_mask_);
-   if (ret == -1) {
-@@ -342,6 +365,12 @@ bool SubprocessSet::DoWork() {
-     ++i;
-   }
- 
-+  if (tokens) {
-+    int fd = tokens->GetMonitorFd();
-+    if ((fd >= 0) && FD_ISSET(fd, &set))
-+    token_available_ = true;
-+  }
-+
-   return IsInterrupted();
- }
- #endif  // !defined(USE_PPOLL)
+ RealCommandRunner::~RealCommandRunner() {
+diff --git a/src/subprocess-win32.cc b/src/subprocess-win32.cc
+index 66d2c2c430..ce3e2c20a4 100644
 --- a/src/subprocess-win32.cc
 +++ b/src/subprocess-win32.cc
 @@ -13,6 +13,7 @@
@@ -1019,13 +2497,7 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
  
  #include <assert.h>
  #include <stdio.h>
-@@ -251,11 +252,14 @@ Subprocess *SubprocessSet::Add(const str
-   return subprocess;
- }
- 
--bool SubprocessSet::DoWork() {
-+bool SubprocessSet::DoWork(TokenPool* tokens) {
-   DWORD bytes_read;
+@@ -256,6 +257,9 @@ bool SubprocessSet::DoWork(struct TokenPool* tokens) {
    Subprocess* subproc;
    OVERLAPPED* overlapped;
  
@@ -1035,7 +2507,7 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
    if (!GetQueuedCompletionStatus(ioport_, &bytes_read, (PULONG_PTR)&subproc,
                                   &overlapped, INFINITE)) {
      if (GetLastError() != ERROR_BROKEN_PIPE)
-@@ -266,6 +270,11 @@ bool SubprocessSet::DoWork() {
+@@ -266,6 +270,11 @@ bool SubprocessSet::DoWork(struct TokenPool* tokens) {
                  // delivered by NotifyInterrupted above.
      return true;
  
@@ -1047,58 +2519,18 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
    subproc->OnPipeReady();
  
    if (subproc->Done()) {
---- a/src/subprocess.h
-+++ b/src/subprocess.h
-@@ -76,6 +76,8 @@ struct Subprocess {
-   friend struct SubprocessSet;
- };
- 
-+struct TokenPool;
-+
- /// SubprocessSet runs a ppoll/pselect() loop around a set of Subprocesses.
- /// DoWork() waits for any state change in subprocesses; finished_
- /// is a queue of subprocesses as they finish.
-@@ -84,13 +86,17 @@ struct SubprocessSet {
-   ~SubprocessSet();
- 
-   Subprocess* Add(const std::string& command, bool use_console = false);
--  bool DoWork();
-+  bool DoWork(struct TokenPool* tokens);
-   Subprocess* NextFinished();
-   void Clear();
- 
-   std::vector<Subprocess*> running_;
-   std::queue<Subprocess*> finished_;
- 
-+  bool token_available_;
-+  bool IsTokenAvailable() { return token_available_; }
-+  void ResetTokenAvailable() { token_available_ = false; }
-+
- #ifdef _WIN32
-   static BOOL WINAPI NotifyInterrupted(DWORD dwCtrlType);
-   static HANDLE ioport_;
+diff --git a/src/subprocess_test.cc b/src/subprocess_test.cc
+index 6264c8bf11..f625963462 100644
 --- a/src/subprocess_test.cc
 +++ b/src/subprocess_test.cc
-@@ -13,6 +13,7 @@
- // limitations under the License.
- 
- #include "subprocess.h"
-+#include "tokenpool.h"
- 
- #include "test.h"
- 
-@@ -34,8 +35,30 @@ const char* kSimpleCommand = "cmd /c dir
- const char* kSimpleCommand = "ls /";
- #endif
- 
-+struct TestTokenPool : public TokenPool {
-+  bool Acquire()     { return false; }
-+  void Reserve()     {}
-+  void Release()     {}
-+  void Clear()       {}
+@@ -40,9 +40,16 @@ struct TokenPoolTest : public TokenPool {
+   void Reserve()     {}
+   void Release()     {}
+   void Clear()       {}
 +  bool Setup(bool ignore_unused, bool verbose, double& max_load_average) { return false; }
-+
-+#ifdef _WIN32
+ 
+ #ifdef _WIN32
+-  // @TODO
 +  bool _token_available;
 +  void WaitForTokenAvailability(HANDLE ioport) {
 +    if (_token_available)
@@ -1106,197 +2538,31 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
 +      PostQueuedCompletionStatus(ioport, 0, (ULONG_PTR) this, NULL);
 +  }
 +  bool TokenIsAvailable(ULONG_PTR key) { return key == (ULONG_PTR) this; }
-+#else
-+  int _fd;
-+  int GetMonitorFd() { return _fd; }
-+#endif
-+};
-+
- struct SubprocessTest : public testing::Test {
-   SubprocessSet subprocs_;
-+  TestTokenPool tokens_;
- };
- 
- }  // anonymous namespace
-@@ -45,10 +68,12 @@ TEST_F(SubprocessTest, BadCommandStderr)
-   Subprocess* subproc = subprocs_.Add("cmd /c ninja_no_such_command");
-   ASSERT_NE((Subprocess *) 0, subproc);
- 
-+  subprocs_.ResetTokenAvailable();
-   while (!subproc->Done()) {
-     // Pretend we discovered that stderr was ready for writing.
--    subprocs_.DoWork();
-+    subprocs_.DoWork(NULL);
-   }
-+  ASSERT_FALSE(subprocs_.IsTokenAvailable());
- 
-   EXPECT_EQ(ExitFailure, subproc->Finish());
-   EXPECT_NE("", subproc->GetOutput());
-@@ -59,10 +84,12 @@ TEST_F(SubprocessTest, NoSuchCommand) {
-   Subprocess* subproc = subprocs_.Add("ninja_no_such_command");
-   ASSERT_NE((Subprocess *) 0, subproc);
- 
-+  subprocs_.ResetTokenAvailable();
-   while (!subproc->Done()) {
-     // Pretend we discovered that stderr was ready for writing.
--    subprocs_.DoWork();
-+    subprocs_.DoWork(NULL);
-   }
-+  ASSERT_FALSE(subprocs_.IsTokenAvailable());
- 
-   EXPECT_EQ(ExitFailure, subproc->Finish());
-   EXPECT_NE("", subproc->GetOutput());
-@@ -78,9 +105,11 @@ TEST_F(SubprocessTest, InterruptChild) {
-   Subprocess* subproc = subprocs_.Add("kill -INT $$");
-   ASSERT_NE((Subprocess *) 0, subproc);
- 
-+  subprocs_.ResetTokenAvailable();
-   while (!subproc->Done()) {
--    subprocs_.DoWork();
-+    subprocs_.DoWork(NULL);
-   }
-+  ASSERT_FALSE(subprocs_.IsTokenAvailable());
- 
-   EXPECT_EQ(ExitInterrupted, subproc->Finish());
- }
-@@ -90,7 +119,7 @@ TEST_F(SubprocessTest, InterruptParent)
-   ASSERT_NE((Subprocess *) 0, subproc);
- 
-   while (!subproc->Done()) {
--    bool interrupted = subprocs_.DoWork();
-+    bool interrupted = subprocs_.DoWork(NULL);
-     if (interrupted)
-       return;
-   }
-@@ -102,9 +131,11 @@ TEST_F(SubprocessTest, InterruptChildWit
-   Subprocess* subproc = subprocs_.Add("kill -TERM $$");
-   ASSERT_NE((Subprocess *) 0, subproc);
- 
-+  subprocs_.ResetTokenAvailable();
-   while (!subproc->Done()) {
--    subprocs_.DoWork();
-+    subprocs_.DoWork(NULL);
-   }
-+  ASSERT_FALSE(subprocs_.IsTokenAvailable());
- 
-   EXPECT_EQ(ExitInterrupted, subproc->Finish());
+ #else
+   int _fd;
+   int GetMonitorFd() { return _fd; }
+@@ -297,34 +304,48 @@ TEST_F(SubprocessTest, ReadStdin) {
  }
-@@ -114,7 +145,7 @@ TEST_F(SubprocessTest, InterruptParentWi
-   ASSERT_NE((Subprocess *) 0, subproc);
- 
-   while (!subproc->Done()) {
--    bool interrupted = subprocs_.DoWork();
-+    bool interrupted = subprocs_.DoWork(NULL);
-     if (interrupted)
-       return;
-   }
-@@ -126,9 +157,11 @@ TEST_F(SubprocessTest, InterruptChildWit
-   Subprocess* subproc = subprocs_.Add("kill -HUP $$");
-   ASSERT_NE((Subprocess *) 0, subproc);
- 
-+  subprocs_.ResetTokenAvailable();
-   while (!subproc->Done()) {
--    subprocs_.DoWork();
-+    subprocs_.DoWork(NULL);
-   }
-+  ASSERT_FALSE(subprocs_.IsTokenAvailable());
- 
-   EXPECT_EQ(ExitInterrupted, subproc->Finish());
- }
-@@ -138,7 +171,7 @@ TEST_F(SubprocessTest, InterruptParentWi
-   ASSERT_NE((Subprocess *) 0, subproc);
- 
-   while (!subproc->Done()) {
--    bool interrupted = subprocs_.DoWork();
-+    bool interrupted = subprocs_.DoWork(NULL);
-     if (interrupted)
-       return;
-   }
-@@ -153,9 +186,11 @@ TEST_F(SubprocessTest, Console) {
-         subprocs_.Add("test -t 0 -a -t 1 -a -t 2", /*use_console=*/true);
-     ASSERT_NE((Subprocess*)0, subproc);
- 
-+    subprocs_.ResetTokenAvailable();
-     while (!subproc->Done()) {
--      subprocs_.DoWork();
-+      subprocs_.DoWork(NULL);
-     }
-+    ASSERT_FALSE(subprocs_.IsTokenAvailable());
+ #endif  // _WIN32
  
-     EXPECT_EQ(ExitSuccess, subproc->Finish());
-   }
-@@ -167,9 +202,11 @@ TEST_F(SubprocessTest, SetWithSingle) {
+-// @TODO: remove once TokenPool implementation for Windows is available
+-#ifndef _WIN32
+ TEST_F(SubprocessTest, TokenAvailable) {
    Subprocess* subproc = subprocs_.Add(kSimpleCommand);
    ASSERT_NE((Subprocess *) 0, subproc);
  
-+  subprocs_.ResetTokenAvailable();
-   while (!subproc->Done()) {
--    subprocs_.DoWork();
-+    subprocs_.DoWork(NULL);
-   }
-+  ASSERT_FALSE(subprocs_.IsTokenAvailable());
-   ASSERT_EQ(ExitSuccess, subproc->Finish());
-   ASSERT_NE("", subproc->GetOutput());
- 
-@@ -200,12 +237,13 @@ TEST_F(SubprocessTest, SetWithMulti) {
-     ASSERT_EQ("", processes[i]->GetOutput());
-   }
- 
-+  subprocs_.ResetTokenAvailable();
-   while (!processes[0]->Done() || !processes[1]->Done() ||
-          !processes[2]->Done()) {
-     ASSERT_GT(subprocs_.running_.size(), 0u);
--    subprocs_.DoWork();
-+    subprocs_.DoWork(NULL);
-   }
--
-+  ASSERT_FALSE(subprocs_.IsTokenAvailable());
-   ASSERT_EQ(0u, subprocs_.running_.size());
-   ASSERT_EQ(3u, subprocs_.finished_.size());
- 
-@@ -237,8 +275,10 @@ TEST_F(SubprocessTest, SetWithLots) {
-     ASSERT_NE((Subprocess *) 0, subproc);
-     procs.push_back(subproc);
-   }
-+  subprocs_.ResetTokenAvailable();
-   while (!subprocs_.running_.empty())
--    subprocs_.DoWork();
-+    subprocs_.DoWork(NULL);
-+  ASSERT_FALSE(subprocs_.IsTokenAvailable());
-   for (size_t i = 0; i < procs.size(); ++i) {
-     ASSERT_EQ(ExitSuccess, procs[i]->Finish());
-     ASSERT_NE("", procs[i]->GetOutput());
-@@ -254,10 +294,91 @@ TEST_F(SubprocessTest, SetWithLots) {
- // that stdin is closed.
- TEST_F(SubprocessTest, ReadStdin) {
-   Subprocess* subproc = subprocs_.Add("cat -");
-+  subprocs_.ResetTokenAvailable();
-   while (!subproc->Done()) {
--    subprocs_.DoWork();
-+    subprocs_.DoWork(NULL);
-   }
-+  ASSERT_FALSE(subprocs_.IsTokenAvailable());
-   ASSERT_EQ(ExitSuccess, subproc->Finish());
-   ASSERT_EQ(1u, subprocs_.finished_.size());
- }
- #endif  // _WIN32
-+
-+TEST_F(SubprocessTest, TokenAvailable) {
-+  Subprocess* subproc = subprocs_.Add(kSimpleCommand);
-+  ASSERT_NE((Subprocess *) 0, subproc);
-+
-+  // simulate GNUmake jobserver pipe with 1 token
+   // simulate GNUmake jobserver pipe with 1 token
 +#ifdef _WIN32
 +  tokens_._token_available = true;
 +#else
-+  int fds[2];
-+  ASSERT_EQ(0u, pipe(fds));
-+  tokens_._fd = fds[0];
-+  ASSERT_EQ(1u, write(fds[1], "T", 1));
+   int fds[2];
+   ASSERT_EQ(0u, pipe(fds));
+   tokens_._fd = fds[0];
+   ASSERT_EQ(1u, write(fds[1], "T", 1));
 +#endif
-+
-+  subprocs_.ResetTokenAvailable();
-+  subprocs_.DoWork(&tokens_);
+ 
+   subprocs_.ResetTokenAvailable();
+   subprocs_.DoWork(&tokens_);
 +#ifdef _WIN32
 +  tokens_._token_available = false;
 +  // we need to loop here as we have no conrol where the token
@@ -1305,63 +2571,62 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
 +    subprocs_.DoWork(&tokens_);
 +  }
 +#endif
-+
-+  EXPECT_TRUE(subprocs_.IsTokenAvailable());
-+  EXPECT_EQ(0u, subprocs_.finished_.size());
-+
-+  // remove token to let DoWork() wait for command again
+ 
+   EXPECT_TRUE(subprocs_.IsTokenAvailable());
+   EXPECT_EQ(0u, subprocs_.finished_.size());
+ 
+   // remove token to let DoWork() wait for command again
 +#ifndef _WIN32
-+  char token;
-+  ASSERT_EQ(1u, read(fds[0], &token, 1));
+   char token;
+   ASSERT_EQ(1u, read(fds[0], &token, 1));
 +#endif
-+
-+  while (!subproc->Done()) {
-+    subprocs_.DoWork(&tokens_);
-+  }
-+
+ 
+   while (!subproc->Done()) {
+     subprocs_.DoWork(&tokens_);
+   }
+ 
 +#ifndef _WIN32
-+  close(fds[1]);
-+  close(fds[0]);
+   close(fds[1]);
+   close(fds[0]);
 +#endif
-+
-+  EXPECT_EQ(ExitSuccess, subproc->Finish());
-+  EXPECT_NE("", subproc->GetOutput());
-+
-+  EXPECT_EQ(1u, subprocs_.finished_.size());
-+}
-+
-+TEST_F(SubprocessTest, TokenNotAvailable) {
-+  Subprocess* subproc = subprocs_.Add(kSimpleCommand);
-+  ASSERT_NE((Subprocess *) 0, subproc);
-+
-+  // simulate GNUmake jobserver pipe with 0 tokens
+ 
+   EXPECT_EQ(ExitSuccess, subproc->Finish());
+   EXPECT_NE("", subproc->GetOutput());
+@@ -337,17 +358,23 @@ TEST_F(SubprocessTest, TokenNotAvailable) {
+   ASSERT_NE((Subprocess *) 0, subproc);
+ 
+   // simulate GNUmake jobserver pipe with 0 tokens
 +#ifdef _WIN32
 +  tokens_._token_available = false;
 +#else
-+  int fds[2];
-+  ASSERT_EQ(0u, pipe(fds));
-+  tokens_._fd = fds[0];
+   int fds[2];
+   ASSERT_EQ(0u, pipe(fds));
+   tokens_._fd = fds[0];
 +#endif
-+
-+  subprocs_.ResetTokenAvailable();
-+  while (!subproc->Done()) {
-+    subprocs_.DoWork(&tokens_);
-+  }
-+
+ 
+   subprocs_.ResetTokenAvailable();
+   while (!subproc->Done()) {
+     subprocs_.DoWork(&tokens_);
+   }
+ 
 +#ifndef _WIN32
-+  close(fds[1]);
-+  close(fds[0]);
+   close(fds[1]);
+   close(fds[0]);
 +#endif
-+
-+  EXPECT_FALSE(subprocs_.IsTokenAvailable());
-+  EXPECT_EQ(ExitSuccess, subproc->Finish());
-+  EXPECT_NE("", subproc->GetOutput());
-+
-+  EXPECT_EQ(1u, subprocs_.finished_.size());
-+}
+ 
+   EXPECT_FALSE(subprocs_.IsTokenAvailable());
+   EXPECT_EQ(ExitSuccess, subproc->Finish());
+@@ -355,4 +382,3 @@ TEST_F(SubprocessTest, TokenNotAvailable) {
+ 
+   EXPECT_EQ(1u, subprocs_.finished_.size());
+ }
+-#endif  // _WIN32
+diff --git a/src/tokenpool-gnu-make-posix.cc b/src/tokenpool-gnu-make-posix.cc
+new file mode 100644
+index 0000000000..70d84bfff7
 --- /dev/null
 +++ b/src/tokenpool-gnu-make-posix.cc
-@@ -0,0 +1,202 @@
+@@ -0,0 +1,203 @@
 +// Copyright 2016-2018 Google Inc. All Rights Reserved.
 +//
 +// Licensed under the Apache License, Version 2.0 (the "License");
@@ -1396,8 +2661,8 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
 +
 +  virtual int GetMonitorFd();
 +
-+  virtual const char* GetEnv(const char* name) { return getenv(name); };
-+  virtual bool ParseAuth(const char* jobserver);
++  virtual const char *GetEnv(const char *name) { return getenv(name); };
++  virtual bool ParseAuth(const char *jobserver);
 +  virtual bool AcquireToken();
 +  virtual bool ReturnToken();
 +
@@ -1446,13 +2711,14 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
 +  act.sa_handler = CloseDupRfd;
 +  if (sigaction(SIGALRM, &act, &old_act_) < 0) {
 +    perror("sigaction:");
-+    return false;
++    return(false);
++  } else {
++    restore_ = true;
++    return(true);
 +  }
-+  restore_ = true;
-+  return true;
 +}
 +
-+bool GNUmakeTokenPoolPosix::ParseAuth(const char* jobserver) {
++bool GNUmakeTokenPoolPosix::ParseAuth(const char *jobserver) {
 +  int rfd = -1;
 +  int wfd = -1;
 +  if ((sscanf(jobserver, "%*[^=]=%d,%d", &rfd, &wfd) == 2) &&
@@ -1558,15 +2824,18 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
 +}
 +
 +int GNUmakeTokenPoolPosix::GetMonitorFd() {
-+  return rfd_;
++  return(rfd_);
 +}
 +
-+TokenPool* TokenPool::Get() {
++struct TokenPool *TokenPool::Get() {
 +  return new GNUmakeTokenPoolPosix;
 +}
+diff --git a/src/tokenpool-gnu-make-win32.cc b/src/tokenpool-gnu-make-win32.cc
+new file mode 100644
+index 0000000000..2719f2c1fc
 --- /dev/null
 +++ b/src/tokenpool-gnu-make-win32.cc
-@@ -0,0 +1,239 @@
+@@ -0,0 +1,237 @@
 +// Copyright 2018 Google Inc. All Rights Reserved.
 +//
 +// Licensed under the Apache License, Version 2.0 (the "License");
@@ -1583,8 +2852,7 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
 +
 +#include "tokenpool-gnu-make.h"
 +
-+// Always include this first.
-+// Otherwise the other system headers don't work correctly under Win32
++// always include first to make sure other headers do the correct thing...
 +#include <windows.h>
 +
 +#include <ctype.h>
@@ -1602,8 +2870,8 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
 +  virtual void WaitForTokenAvailability(HANDLE ioport);
 +  virtual bool TokenIsAvailable(ULONG_PTR key);
 +
-+  virtual const char* GetEnv(const char* name);
-+  virtual bool ParseAuth(const char* jobserver);
++  virtual const char *GetEnv(const char *name);
++  virtual bool ParseAuth(const char *jobserver);
 +  virtual bool AcquireToken();
 +  virtual bool ReturnToken();
 +
@@ -1668,19 +2936,19 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
 +  }
 +}
 +
-+const char* GNUmakeTokenPoolWin32::GetEnv(const char* name) {
++const char *GNUmakeTokenPoolWin32::GetEnv(const char *name) {
 +  // getenv() does not work correctly together with tokenpool_tests.cc
 +  static char buffer[MAX_PATH + 1];
-+  if (GetEnvironmentVariable(name, buffer, sizeof(buffer)) == 0)
++  if (GetEnvironmentVariable("MAKEFLAGS", buffer, sizeof(buffer)) == 0)
 +    return NULL;
-+  return buffer;
++  return(buffer);
 +}
 +
-+bool GNUmakeTokenPoolWin32::ParseAuth(const char* jobserver) {
++bool GNUmakeTokenPoolWin32::ParseAuth(const char *jobserver) {
 +  // match "--jobserver-auth=gmake_semaphore_<INTEGER>..."
-+  const char* start = strchr(jobserver, '=');
++  const char *start = strchr(jobserver, '=');
 +  if (start) {
-+    const char* end = start;
++    const char *end = start;
 +    unsigned int len;
 +    char c, *auth;
 +
@@ -1689,15 +2957,14 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
 +        break;
 +    len = end - start; // includes string terminator in count
 +
-+    if ((len > 1) && ((auth = (char*)malloc(len)) != NULL)) {
++    if ((len > 1) && ((auth = (char *)malloc(len)) != NULL)) {
 +      strncpy(auth, start + 1, len - 1);
 +      auth[len - 1] = '\0';
 +
-+      if ((semaphore_jobserver_ =
-+           OpenSemaphore(SEMAPHORE_ALL_ACCESS, /* Semaphore access setting */
-+                         FALSE,                /* Child processes DON'T inherit */
-+                         auth                  /* Semaphore name */
-+                        )) != NULL) {
++      if ((semaphore_jobserver_ = OpenSemaphore(SEMAPHORE_ALL_ACCESS, /* Semaphore access setting */
++                                                FALSE,                /* Child processes DON'T inherit */
++                                                auth                  /* Semaphore name */
++                                                )) != NULL) {
 +        free(auth);
 +        return true;
 +      }
@@ -1742,7 +3009,7 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
 +}
 +
 +DWORD WINAPI GNUmakeTokenPoolWin32::SemaphoreThreadWrapper(LPVOID param) {
-+  GNUmakeTokenPoolWin32* This = (GNUmakeTokenPoolWin32*) param;
++  GNUmakeTokenPoolWin32 *This = (GNUmakeTokenPoolWin32 *) param;
 +  return This->SemaphoreThread();
 +}
 +
@@ -1787,7 +3054,7 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
 +
 +bool GNUmakeTokenPoolWin32::TokenIsAvailable(ULONG_PTR key) {
 +  // alert child thread to break wait on token semaphore
-+  QueueUserAPC((PAPCFUNC)&NoopAPCFunc, child_, (ULONG_PTR)NULL);
++  QueueUserAPC(&NoopAPCFunc, child_, (ULONG_PTR)NULL);
 +
 +  // return true when GetQueuedCompletionStatus() returned our key
 +  return key == (ULONG_PTR) this;
@@ -1803,120 +3070,273 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
 +    Win32Fatal("WaitForSingleObject");
 +}
 +
-+TokenPool* TokenPool::Get() {
++struct TokenPool *TokenPool::Get() {
 +  return new GNUmakeTokenPoolWin32;
 +}
---- /dev/null
+diff --git a/src/tokenpool-gnu-make.cc b/src/tokenpool-gnu-make.cc
+index 4132bb06d9..92ff611721 100644
+--- a/src/tokenpool-gnu-make.cc
 +++ b/src/tokenpool-gnu-make.cc
-@@ -0,0 +1,108 @@
-+// Copyright 2016-2018 Google Inc. All Rights Reserved.
-+//
-+// Licensed under the Apache License, Version 2.0 (the "License");
-+// you may not use this file except in compliance with the License.
-+// You may obtain a copy of the License at
-+//
-+//     http://www.apache.org/licenses/LICENSE-2.0
-+//
-+// Unless required by applicable law or agreed to in writing, software
-+// distributed under the License is distributed on an "AS IS" BASIS,
-+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-+// See the License for the specific language governing permissions and
-+// limitations under the License.
-+
+@@ -12,101 +12,26 @@
+ // See the License for the specific language governing permissions and
+ // limitations under the License.
+ 
+-#include "tokenpool.h"
 +#include "tokenpool-gnu-make.h"
-+
+ 
+-#include <errno.h>
+-#include <fcntl.h>
+-#include <poll.h>
+-#include <unistd.h>
+-#include <signal.h>
+-#include <sys/time.h>
 +#include <stdlib.h>
-+#include <stdio.h>
-+#include <string.h>
-+
-+#include "line_printer.h"
-+
+ #include <stdio.h>
+ #include <string.h>
+-#include <stdlib.h>
+ 
+ #include "line_printer.h"
+ 
+-// TokenPool implementation for GNU make jobserver
+-// (http://make.mad-scientist.net/papers/jobserver-implementation/)
+-struct GNUmakeTokenPool : public TokenPool {
+-  GNUmakeTokenPool();
+-  virtual ~GNUmakeTokenPool();
+-
+-  virtual bool Acquire();
+-  virtual void Reserve();
+-  virtual void Release();
+-  virtual void Clear();
+-  virtual int GetMonitorFd();
+-
+-  bool Setup(bool ignore, bool verbose, double& max_load_average);
+-
+- private:
+-  int available_;
+-  int used_;
+-
+-#ifdef _WIN32
+-  // @TODO
+-#else
+-  int rfd_;
+-  int wfd_;
+-
+-  struct sigaction old_act_;
+-  bool restore_;
+-
+-  static int dup_rfd_;
+-  static void CloseDupRfd(int signum);
+-
+-  bool CheckFd(int fd);
+-  bool SetAlarmHandler();
+-#endif
+-
+-  void Return();
+-};
+-
 +// TokenPool implementation for GNU make jobserver - common bits
-+// every instance owns an implicit token -> available_ == 1
+ // every instance owns an implicit token -> available_ == 1
+-GNUmakeTokenPool::GNUmakeTokenPool() : available_(1), used_(0),
+-                                       rfd_(-1), wfd_(-1), restore_(false) {
 +GNUmakeTokenPool::GNUmakeTokenPool() : available_(1), used_(0) {
-+}
-+
-+GNUmakeTokenPool::~GNUmakeTokenPool() {
-+}
-+
-+bool GNUmakeTokenPool::Setup(bool ignore,
-+                             bool verbose,
-+                             double& max_load_average) {
-+  const char* value = GetEnv("MAKEFLAGS");
-+  if (!value)
-+    return false;
-+
-+  // GNU make <= 4.1
-+  const char* jobserver = strstr(value, "--jobserver-fds=");
-+  if (!jobserver)
-+    // GNU make => 4.2
-+    jobserver = strstr(value, "--jobserver-auth=");
-+  if (jobserver) {
-+    LinePrinter printer;
-+
-+    if (ignore) {
-+      printer.PrintOnNewLine("ninja: warning: -jN forced on command line; ignoring GNU make jobserver.\n");
-+    } else {
-+      if (ParseAuth(jobserver)) {
-+        const char* l_arg = strstr(value, " -l");
-+        int load_limit = -1;
-+
-+        if (verbose) {
-+          printer.PrintOnNewLine("ninja: using GNU make jobserver.\n");
-+        }
-+
-+        // translate GNU make -lN to ninja -lN
-+        if (l_arg &&
-+            (sscanf(l_arg + 3, "%d ", &load_limit) == 1) &&
-+            (load_limit > 0)) {
-+          max_load_average = load_limit;
-+        }
-+
-+        return true;
-+      }
-+    }
-+  }
-+
-+  return false;
-+}
-+
-+bool GNUmakeTokenPool::Acquire() {
-+  if (available_ > 0)
-+    return true;
-+
+ }
+ 
+ GNUmakeTokenPool::~GNUmakeTokenPool() {
+-  Clear();
+-  if (restore_)
+-    sigaction(SIGALRM, &old_act_, NULL);
+-}
+-
+-bool GNUmakeTokenPool::CheckFd(int fd) {
+-  if (fd < 0)
+-    return false;
+-  int ret = fcntl(fd, F_GETFD);
+-  if (ret < 0)
+-    return false;
+-  return true;
+-}
+-
+-int GNUmakeTokenPool::dup_rfd_ = -1;
+-
+-void GNUmakeTokenPool::CloseDupRfd(int signum) {
+-  close(dup_rfd_);
+-  dup_rfd_ = -1;
+-}
+-
+-bool GNUmakeTokenPool::SetAlarmHandler() {
+-  struct sigaction act;
+-  memset(&act, 0, sizeof(act));
+-  act.sa_handler = CloseDupRfd;
+-  if (sigaction(SIGALRM, &act, &old_act_) < 0) {
+-    perror("sigaction:");
+-    return(false);
+-  } else {
+-    restore_ = true;
+-    return(true);
+-  }
+ }
+ 
+ bool GNUmakeTokenPool::Setup(bool ignore,
+                              bool verbose,
+                              double& max_load_average) {
+-  const char *value = getenv("MAKEFLAGS");
++  const char *value = GetEnv("MAKEFLAGS");
+   if (value) {
+     // GNU make <= 4.1
+     const char *jobserver = strstr(value, "--jobserver-fds=");
+@@ -119,20 +44,13 @@ bool GNUmakeTokenPool::Setup(bool ignore,
+       if (ignore) {
+         printer.PrintOnNewLine("ninja: warning: -jN forced on command line; ignoring GNU make jobserver.\n");
+       } else {
+-        int rfd = -1;
+-        int wfd = -1;
+-        if ((sscanf(jobserver, "%*[^=]=%d,%d", &rfd, &wfd) == 2) &&
+-            CheckFd(rfd) &&
+-            CheckFd(wfd) &&
+-            SetAlarmHandler()) {
++        if (ParseAuth(jobserver)) {
+           const char *l_arg = strstr(value, " -l");
+           int load_limit = -1;
+ 
+           if (verbose) {
+             printer.PrintOnNewLine("ninja: using GNU make jobserver.\n");
+           }
+-          rfd_ = rfd;
+-          wfd_ = wfd;
+ 
+           // translate GNU make -lN to ninja -lN
+           if (l_arg &&
+@@ -154,83 +72,14 @@ bool GNUmakeTokenPool::Acquire() {
+   if (available_ > 0)
+     return true;
+ 
+-  // Please read
+-  //
+-  //   http://make.mad-scientist.net/papers/jobserver-implementation/
+-  //
+-  // for the reasoning behind the following code.
+-  //
+-  // Try to read one character from the pipe. Returns true on success.
+-  //
+-  // First check if read() would succeed without blocking.
+-#ifdef USE_PPOLL
+-  pollfd pollfds[] = {{rfd_, POLLIN, 0}};
+-  int ret = poll(pollfds, 1, 0);
+-#else
+-  fd_set set;
+-  struct timeval timeout = { 0, 0 };
+-  FD_ZERO(&set);
+-  FD_SET(rfd_, &set);
+-  int ret = select(rfd_ + 1, &set, NULL, NULL, &timeout);
+-#endif
+-  if (ret > 0) {
+-    // Handle potential race condition:
+-    //  - the above check succeeded, i.e. read() should not block
+-    //  - the character disappears before we call read()
+-    //
+-    // Create a duplicate of rfd_. The duplicate file descriptor dup_rfd_
+-    // can safely be closed by signal handlers without affecting rfd_.
+-    dup_rfd_ = dup(rfd_);
+-
+-    if (dup_rfd_ != -1) {
+-      struct sigaction act, old_act;
+-      int ret = 0;
+-
+-      // Temporarily replace SIGCHLD handler with our own
+-      memset(&act, 0, sizeof(act));
+-      act.sa_handler = CloseDupRfd;
+-      if (sigaction(SIGCHLD, &act, &old_act) == 0) {
+-        struct itimerval timeout;
+-
+-        // install a 100ms timeout that generates SIGALARM on expiration
+-        memset(&timeout, 0, sizeof(timeout));
+-        timeout.it_value.tv_usec = 100 * 1000; // [ms] -> [usec]
+-        if (setitimer(ITIMER_REAL, &timeout, NULL) == 0) {
+-          char buf;
+-
+-          // Now try to read() from dup_rfd_. Return values from read():
+-          //
+-          // 1. token read                               ->  1
+-          // 2. pipe closed                              ->  0
+-          // 3. alarm expires                            -> -1 (EINTR)
+-          // 4. child exits                              -> -1 (EINTR)
+-          // 5. alarm expired before entering read()     -> -1 (EBADF)
+-          // 6. child exited before entering read()      -> -1 (EBADF)
+-          // 7. child exited before handler is installed -> go to 1 - 3
+-          ret = read(dup_rfd_, &buf, 1);
+-
+-          // disarm timer
+-          memset(&timeout, 0, sizeof(timeout));
+-          setitimer(ITIMER_REAL, &timeout, NULL);
+-        }
+-
+-        sigaction(SIGCHLD, &old_act, NULL);
+-      }
+-
+-      CloseDupRfd(0);
+-
+-      // Case 1 from above list
+-      if (ret > 0) {
+-        available_++;
+-        return true;
+-      }
+-    }
 +  if (AcquireToken()) {
 +    // token acquired
 +    available_++;
 +    return true;
-+  }
-+
-+  // no token available
-+  return false;
-+}
-+
-+void GNUmakeTokenPool::Reserve() {
-+  available_--;
-+  used_++;
-+}
-+
-+void GNUmakeTokenPool::Return() {
++  } else {
++    // no token available
++    return false;
+   }
+-
+-  // read() would block, i.e. no token available,
+-  // cases 2-6 from above list or
+-  // select() / poll() / dup() / sigaction() / setitimer() failed
+-  return false;
+ }
+ 
+ void GNUmakeTokenPool::Reserve() {
+@@ -239,15 +88,8 @@ void GNUmakeTokenPool::Reserve() {
+ }
+ 
+ void GNUmakeTokenPool::Return() {
+-  const char buf = '+';
+-  while (1) {
+-    int ret = write(wfd_, &buf, 1);
+-    if (ret > 0)
+-      available_--;
+-    if ((ret != -1) || (errno != EINTR))
+-      return;
+-    // write got interrupted - retry
+-  }
 +  if (ReturnToken())
 +    available_--;
-+}
-+
-+void GNUmakeTokenPool::Release() {
-+  available_++;
-+  used_--;
-+  if (available_ > 1)
-+    Return();
-+}
-+
-+void GNUmakeTokenPool::Clear() {
-+  while (used_ > 0)
-+    Release();
-+  while (available_ > 1)
-+    Return();
-+}
+ }
+ 
+ void GNUmakeTokenPool::Release() {
+@@ -263,18 +105,3 @@ void GNUmakeTokenPool::Clear() {
+   while (available_ > 1)
+     Return();
+ }
+-
+-int GNUmakeTokenPool::GetMonitorFd() {
+-  return(rfd_);
+-}
+-
+-struct TokenPool *TokenPool::Get(bool ignore,
+-                                 bool verbose,
+-                                 double& max_load_average) {
+-  GNUmakeTokenPool *tokenpool = new GNUmakeTokenPool;
+-  if (tokenpool->Setup(ignore, verbose, max_load_average))
+-    return tokenpool;
+-  else
+-    delete tokenpool;
+-  return NULL;
+-}
+diff --git a/src/tokenpool-gnu-make.h b/src/tokenpool-gnu-make.h
+new file mode 100644
+index 0000000000..d3852088e2
 --- /dev/null
 +++ b/src/tokenpool-gnu-make.h
 @@ -0,0 +1,40 @@
@@ -1939,7 +3359,7 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
 +// interface to GNU make token pool
 +struct GNUmakeTokenPool : public TokenPool {
 +  GNUmakeTokenPool();
-+  ~GNUmakeTokenPool();
++  virtual ~GNUmakeTokenPool();
 +
 +  // token pool implementation
 +  virtual bool Acquire();
@@ -1949,8 +3369,8 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
 +  virtual bool Setup(bool ignore, bool verbose, double& max_load_average);
 +
 +  // platform specific implementation
-+  virtual const char* GetEnv(const char* name) = 0;
-+  virtual bool ParseAuth(const char* jobserver) = 0;
++  virtual const char *GetEnv(const char *name) = 0;
++  virtual bool ParseAuth(const char *jobserver) = 0;
 +  virtual bool AcquireToken() = 0;
 +  virtual bool ReturnToken() = 0;
 +
@@ -1960,81 +3380,83 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
 +
 +  void Return();
 +};
---- /dev/null
+diff --git a/src/tokenpool-none.cc b/src/tokenpool-none.cc
+index 4c592875b4..613d16882d 100644
+--- a/src/tokenpool-none.cc
++++ b/src/tokenpool-none.cc
+@@ -17,8 +17,6 @@
+ #include <stdlib.h>
+ 
+ // No-op TokenPool implementation
+-struct TokenPool *TokenPool::Get(bool ignore,
+-                                 bool verbose,
+-                                 double& max_load_average) {
++struct TokenPool *TokenPool::Get() {
+   return NULL;
+ }
+diff --git a/src/tokenpool.h b/src/tokenpool.h
+index 4bf477f20c..1be8e1d5ce 100644
+--- a/src/tokenpool.h
 +++ b/src/tokenpool.h
-@@ -0,0 +1,42 @@
+@@ -1,4 +1,4 @@
+-// Copyright 2016-2017 Google Inc. All Rights Reserved.
 +// Copyright 2016-2018 Google Inc. All Rights Reserved.
-+//
-+// Licensed under the Apache License, Version 2.0 (the "License");
-+// you may not use this file except in compliance with the License.
-+// You may obtain a copy of the License at
-+//
-+//     http://www.apache.org/licenses/LICENSE-2.0
-+//
-+// Unless required by applicable law or agreed to in writing, software
-+// distributed under the License is distributed on an "AS IS" BASIS,
-+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-+// See the License for the specific language governing permissions and
-+// limitations under the License.
-+
+ //
+ // Licensed under the Apache License, Version 2.0 (the "License");
+ // you may not use this file except in compliance with the License.
+@@ -12,6 +12,10 @@
+ // See the License for the specific language governing permissions and
+ // limitations under the License.
+ 
 +#ifdef _WIN32
 +#include <windows.h>
 +#endif
 +
-+// interface to token pool
-+struct TokenPool {
-+  virtual ~TokenPool() {}
-+
-+  virtual bool Acquire() = 0;
-+  virtual void Reserve() = 0;
-+  virtual void Release() = 0;
-+  virtual void Clear() = 0;
-+
+ // interface to token pool
+ struct TokenPool {
+   virtual ~TokenPool() {}
+@@ -21,14 +25,18 @@ struct TokenPool {
+   virtual void Release() = 0;
+   virtual void Clear() = 0;
+ 
 +  // returns false if token pool setup failed
 +  virtual bool Setup(bool ignore, bool verbose, double& max_load_average) = 0;
 +
-+#ifdef _WIN32
+ #ifdef _WIN32
+-  // @TODO
 +  virtual void WaitForTokenAvailability(HANDLE ioport) = 0;
 +  // returns true if a token has become available
 +  // key is result from GetQueuedCompletionStatus()
 +  virtual bool TokenIsAvailable(ULONG_PTR key) = 0;
-+#else
-+  virtual int GetMonitorFd() = 0;
-+#endif
-+
-+  // returns NULL if token pool is not available
-+  static TokenPool* Get();
-+};
---- /dev/null
+ #else
+   virtual int GetMonitorFd() = 0;
+ #endif
+ 
+   // returns NULL if token pool is not available
+-  static struct TokenPool *Get(bool ignore,
+-                               bool verbose,
+-                               double& max_load_average);
++  static struct TokenPool *Get();
+ };
+diff --git a/src/tokenpool_test.cc b/src/tokenpool_test.cc
+index 6c89064ca4..8d4fd7d33a 100644
+--- a/src/tokenpool_test.cc
 +++ b/src/tokenpool_test.cc
-@@ -0,0 +1,269 @@
-+// Copyright 2018 Google Inc. All Rights Reserved.
-+//
-+// Licensed under the Apache License, Version 2.0 (the "License");
-+// you may not use this file except in compliance with the License.
-+// You may obtain a copy of the License at
-+//
-+//     http://www.apache.org/licenses/LICENSE-2.0
-+//
-+// Unless required by applicable law or agreed to in writing, software
-+// distributed under the License is distributed on an "AS IS" BASIS,
-+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-+// See the License for the specific language governing permissions and
-+// limitations under the License.
-+
-+#include "tokenpool.h"
-+
-+#include "test.h"
-+
+@@ -16,13 +16,25 @@
+ 
+ #include "test.h"
+ 
+-#ifndef _WIN32
 +#ifdef _WIN32
 +#include <windows.h>
 +#else
 +#include <unistd.h>
 +#endif
 +
-+#include <stdio.h>
-+#include <stdlib.h>
-+
+ #include <stdio.h>
+ #include <stdlib.h>
+-#include <unistd.h>
+ 
 +#ifdef _WIN32
 +// should contain all valid characters
 +#define SEMAPHORE_NAME      "abcdefghijklmnopqrstwxyz01234567890_"
@@ -2043,40 +3465,45 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
 +#define ENVIRONMENT_INIT(v) SetEnvironmentVariable("MAKEFLAGS", v)
 +#else
 +#define AUTH_FORMAT(tmpl)   "foo " tmpl "=%d,%d bar"
-+#define ENVIRONMENT_CLEAR() unsetenv("MAKEFLAGS")
+ #define ENVIRONMENT_CLEAR() unsetenv("MAKEFLAGS")
+-#define ENVIRONMENT_INIT(v) setenv("MAKEFLAGS", v, true);
 +#define ENVIRONMENT_INIT(v) setenv("MAKEFLAGS", v, true)
-+#endif
-+
-+namespace {
-+
-+const double kLoadAverageDefault = -1.23456789;
-+
-+struct TokenPoolTest : public testing::Test {
-+  double load_avg_;
-+  TokenPool* tokens_;
-+  char buf_[1024];
+ #endif
+ 
+ namespace {
+@@ -32,43 +44,60 @@ const double kLoadAverageDefault = -1.23456789;
+ struct TokenPoolTest : public testing::Test {
+   double load_avg_;
+   TokenPool *tokens_;
+-#ifndef _WIN32
+   char buf_[1024];
 +#ifdef _WIN32
-+  const char* semaphore_name_;
++  const char *semaphore_name_;
 +  HANDLE semaphore_;
 +#else
-+  int fds_[2];
-+#endif
-+
-+  virtual void SetUp() {
-+    load_avg_ = kLoadAverageDefault;
-+    tokens_ = NULL;
-+    ENVIRONMENT_CLEAR();
+   int fds_[2];
+ #endif
+ 
+   virtual void SetUp() {
+     load_avg_ = kLoadAverageDefault;
+     tokens_ = NULL;
+-#ifndef _WIN32
+     ENVIRONMENT_CLEAR();
 +#ifdef _WIN32
 +    semaphore_name_ = SEMAPHORE_NAME;
 +    if ((semaphore_ = CreateSemaphore(0, 0, 2, SEMAPHORE_NAME)) == NULL)
 +#else
-+    if (pipe(fds_) < 0)
-+#endif
+     if (pipe(fds_) < 0)
+-      ASSERT_TRUE(false);
+ #endif
 +      ASSERT_TRUE(false);
-+  }
-+
-+  void CreatePool(const char* format, bool ignore_jobserver = false) {
-+    if (format) {
+   }
+ 
+-  void CreatePool(const char *format, bool ignore_jobserver) {
+-#ifndef _WIN32
++  void CreatePool(const char *format, bool ignore_jobserver = false) {
+     if (format) {
+-      sprintf(buf_, format, fds_[0], fds_[1]);
 +      sprintf(buf_, format,
 +#ifdef _WIN32
 +              semaphore_name_
@@ -2084,73 +3511,69 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
 +              fds_[0], fds_[1]
 +#endif
 +      );
-+      ENVIRONMENT_INIT(buf_);
-+    }
+       ENVIRONMENT_INIT(buf_);
+     }
+-#endif
+-    tokens_ = TokenPool::Get(ignore_jobserver, false, load_avg_);
 +    if ((tokens_ = TokenPool::Get()) != NULL) {
 +      if (!tokens_->Setup(ignore_jobserver, false, load_avg_)) {
 +        delete tokens_;
 +        tokens_ = NULL;
 +      }
 +    }
-+  }
-+
-+  void CreateDefaultPool() {
+   }
+ 
+   void CreateDefaultPool() {
+-    CreatePool("foo --jobserver-auth=%d,%d bar", false);
 +    CreatePool(AUTH_FORMAT("--jobserver-auth"));
-+  }
-+
-+  virtual void TearDown() {
-+    if (tokens_)
-+      delete tokens_;
+   }
+ 
+   virtual void TearDown() {
+     if (tokens_)
+       delete tokens_;
+-#ifndef _WIN32
 +#ifdef _WIN32
 +    CloseHandle(semaphore_);
 +#else
-+    close(fds_[0]);
-+    close(fds_[1]);
-+#endif
+     close(fds_[0]);
+     close(fds_[1]);
+-    ENVIRONMENT_CLEAR();
+ #endif
 +    ENVIRONMENT_CLEAR();
-+  }
-+};
-+
-+} // anonymous namespace
-+
-+// verifies none implementation
-+TEST_F(TokenPoolTest, NoTokenPool) {
-+  CreatePool(NULL, false);
-+
-+  EXPECT_EQ(NULL, tokens_);
-+  EXPECT_EQ(kLoadAverageDefault, load_avg_);
-+}
-+
-+TEST_F(TokenPoolTest, SuccessfulOldSetup) {
-+  // GNUmake <= 4.1
+   }
+ };
+ 
+@@ -82,10 +111,9 @@ TEST_F(TokenPoolTest, NoTokenPool) {
+   EXPECT_EQ(kLoadAverageDefault, load_avg_);
+ }
+ 
+-#ifndef _WIN32
+ TEST_F(TokenPoolTest, SuccessfulOldSetup) {
+   // GNUmake <= 4.1
+-  CreatePool("foo --jobserver-fds=%d,%d bar", false);
 +  CreatePool(AUTH_FORMAT("--jobserver-fds"));
-+
-+  EXPECT_NE(NULL, tokens_);
-+  EXPECT_EQ(kLoadAverageDefault, load_avg_);
-+}
-+
-+TEST_F(TokenPoolTest, SuccessfulNewSetup) {
-+  // GNUmake => 4.2
-+  CreateDefaultPool();
-+
-+  EXPECT_NE(NULL, tokens_);
-+  EXPECT_EQ(kLoadAverageDefault, load_avg_);
-+}
-+
-+TEST_F(TokenPoolTest, IgnoreWithJN) {
+ 
+   EXPECT_NE(NULL, tokens_);
+   EXPECT_EQ(kLoadAverageDefault, load_avg_);
+@@ -100,19 +128,37 @@ TEST_F(TokenPoolTest, SuccessfulNewSetup) {
+ }
+ 
+ TEST_F(TokenPoolTest, IgnoreWithJN) {
+-  CreatePool("foo --jobserver-auth=%d,%d bar", true);
 +  CreatePool(AUTH_FORMAT("--jobserver-auth"), true);
-+
-+  EXPECT_EQ(NULL, tokens_);
-+  EXPECT_EQ(kLoadAverageDefault, load_avg_);
-+}
-+
-+TEST_F(TokenPoolTest, HonorLN) {
+ 
+   EXPECT_EQ(NULL, tokens_);
+   EXPECT_EQ(kLoadAverageDefault, load_avg_);
+ }
+ 
+ TEST_F(TokenPoolTest, HonorLN) {
+-  CreatePool("foo -l9 --jobserver-auth=%d,%d bar", false);
 +  CreatePool(AUTH_FORMAT("-l9 --jobserver-auth"));
-+
-+  EXPECT_NE(NULL, tokens_);
-+  EXPECT_EQ(9.0, load_avg_);
-+}
-+
+ 
+   EXPECT_NE(NULL, tokens_);
+   EXPECT_EQ(9.0, load_avg_);
+ }
+ 
 +#ifdef _WIN32
 +TEST_F(TokenPoolTest, SemaphoreNotFound) {
 +  semaphore_name_ = SEMAPHORE_NAME "_foobar";
@@ -2169,101 +3592,66 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
 +  EXPECT_TRUE(tokens_->TokenIsAvailable((ULONG_PTR)tokens_));
 +}
 +#else
-+TEST_F(TokenPoolTest, MonitorFD) {
-+  CreateDefaultPool();
-+
-+  ASSERT_NE(NULL, tokens_);
-+  EXPECT_EQ(kLoadAverageDefault, load_avg_);
-+
-+  EXPECT_EQ(fds_[0], tokens_->GetMonitorFd());
-+}
+ TEST_F(TokenPoolTest, MonitorFD) {
+   CreateDefaultPool();
+ 
+@@ -121,6 +167,7 @@ TEST_F(TokenPoolTest, MonitorFD) {
+ 
+   EXPECT_EQ(fds_[0], tokens_->GetMonitorFd());
+ }
 +#endif
-+
-+TEST_F(TokenPoolTest, ImplicitToken) {
-+  CreateDefaultPool();
-+
-+  ASSERT_NE(NULL, tokens_);
-+  EXPECT_EQ(kLoadAverageDefault, load_avg_);
-+
-+  EXPECT_TRUE(tokens_->Acquire());
-+  tokens_->Reserve();
-+  EXPECT_FALSE(tokens_->Acquire());
-+  tokens_->Release();
-+  EXPECT_TRUE(tokens_->Acquire());
-+}
-+
-+TEST_F(TokenPoolTest, TwoTokens) {
-+  CreateDefaultPool();
-+
-+  ASSERT_NE(NULL, tokens_);
-+  EXPECT_EQ(kLoadAverageDefault, load_avg_);
-+
-+  // implicit token
-+  EXPECT_TRUE(tokens_->Acquire());
-+  tokens_->Reserve();
-+  EXPECT_FALSE(tokens_->Acquire());
-+
-+  // jobserver offers 2nd token
+ 
+ TEST_F(TokenPoolTest, ImplicitToken) {
+   CreateDefaultPool();
+@@ -147,7 +194,13 @@ TEST_F(TokenPoolTest, TwoTokens) {
+   EXPECT_FALSE(tokens_->Acquire());
+ 
+   // jobserver offers 2nd token
 +#ifdef _WIN32
 +  LONG previous;
 +  ASSERT_TRUE(ReleaseSemaphore(semaphore_, 1, &previous));
 +  ASSERT_EQ(0, previous);
 +#else
-+  ASSERT_EQ(1u, write(fds_[1], "T", 1));
+   ASSERT_EQ(1u, write(fds_[1], "T", 1));
 +#endif
-+  EXPECT_TRUE(tokens_->Acquire());
-+  tokens_->Reserve();
-+  EXPECT_FALSE(tokens_->Acquire());
-+
-+  // release 2nd token
-+  tokens_->Release();
-+  EXPECT_TRUE(tokens_->Acquire());
-+
-+  // release implict token - must return 2nd token back to jobserver
-+  tokens_->Release();
-+  EXPECT_TRUE(tokens_->Acquire());
-+
+   EXPECT_TRUE(tokens_->Acquire());
+   tokens_->Reserve();
+   EXPECT_FALSE(tokens_->Acquire());
+@@ -160,8 +213,14 @@ TEST_F(TokenPoolTest, TwoTokens) {
+   tokens_->Release();
+   EXPECT_TRUE(tokens_->Acquire());
+ 
+-  // there must be one token in the pipe
 +  // there must be one token available
 +#ifdef _WIN32
 +  EXPECT_EQ(WAIT_OBJECT_0, WaitForSingleObject(semaphore_, 0));
 +  EXPECT_TRUE(ReleaseSemaphore(semaphore_, 1, &previous));
 +  EXPECT_EQ(0, previous);
 +#else
-+  EXPECT_EQ(1u, read(fds_[0], buf_, sizeof(buf_)));
+   EXPECT_EQ(1u, read(fds_[0], buf_, sizeof(buf_)));
 +#endif
-+
-+  // implicit token
-+  EXPECT_TRUE(tokens_->Acquire());
-+}
-+
-+TEST_F(TokenPoolTest, Clear) {
-+  CreateDefaultPool();
-+
-+  ASSERT_NE(NULL, tokens_);
-+  EXPECT_EQ(kLoadAverageDefault, load_avg_);
-+
-+  // implicit token
-+  EXPECT_TRUE(tokens_->Acquire());
-+  tokens_->Reserve();
-+  EXPECT_FALSE(tokens_->Acquire());
-+
-+  // jobserver offers 2nd & 3rd token
+ 
+   // implicit token
+   EXPECT_TRUE(tokens_->Acquire());
+@@ -179,7 +238,13 @@ TEST_F(TokenPoolTest, Clear) {
+   EXPECT_FALSE(tokens_->Acquire());
+ 
+   // jobserver offers 2nd & 3rd token
 +#ifdef _WIN32
 +  LONG previous;
 +  ASSERT_TRUE(ReleaseSemaphore(semaphore_, 2, &previous));
 +  ASSERT_EQ(0, previous);
 +#else
-+  ASSERT_EQ(2u, write(fds_[1], "TT", 2));
+   ASSERT_EQ(2u, write(fds_[1], "TT", 2));
 +#endif
-+  EXPECT_TRUE(tokens_->Acquire());
-+  tokens_->Reserve();
-+  EXPECT_TRUE(tokens_->Acquire());
-+  tokens_->Reserve();
-+  EXPECT_FALSE(tokens_->Acquire());
-+
-+  tokens_->Clear();
-+  EXPECT_TRUE(tokens_->Acquire());
-+
+   EXPECT_TRUE(tokens_->Acquire());
+   tokens_->Reserve();
+   EXPECT_TRUE(tokens_->Acquire());
+@@ -189,10 +254,16 @@ TEST_F(TokenPoolTest, Clear) {
+   tokens_->Clear();
+   EXPECT_TRUE(tokens_->Acquire());
+ 
+-  // there must be two tokens in the pipe
 +  // there must be two tokens available
 +#ifdef _WIN32
 +  EXPECT_EQ(WAIT_OBJECT_0, WaitForSingleObject(semaphore_, 0));
@@ -2271,9 +3659,632 @@ https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
 +  EXPECT_TRUE(ReleaseSemaphore(semaphore_, 2, &previous));
 +  EXPECT_EQ(0, previous);
 +#else
-+  EXPECT_EQ(2u, read(fds_[0], buf_, sizeof(buf_)));
+   EXPECT_EQ(2u, read(fds_[0], buf_, sizeof(buf_)));
 +#endif
+ 
+   // implicit token
+   EXPECT_TRUE(tokens_->Acquire());
+ }
+-#endif
+
+From 2b9c81c0ec1226d8795e7725529f13be41eaa385 Mon Sep 17 00:00:00 2001
+From: Stefan Becker <chemobejk@gmail.com>
+Date: Fri, 14 Dec 2018 13:27:11 +0200
+Subject: [PATCH 11/11] Prepare PR for merging - part II
+
+- remove unnecessary "struct" from TokenPool
+- add PAPCFUNC cast to QueryUserAPC()
+- remove hard-coded MAKEFLAGS string from win32
+- remove useless build test CompleteNoWork
+- rename TokenPoolTest to TestTokenPool
+- add tokenpool modules to CMake build
+- remove unused no-op TokenPool implementation
+- fix errors flagged by codespell & clang-tidy
+- address review comments from
+
+https://github.com/ninja-build/ninja/pull/1140#pullrequestreview-195195803
+https://github.com/ninja-build/ninja/pull/1140#pullrequestreview-185089255
+https://github.com/ninja-build/ninja/pull/1140#issuecomment-473898963
+https://github.com/ninja-build/ninja/pull/1140#issuecomment-596624610
+---
+ CMakeLists.txt                  |  8 ++++-
+ src/build.cc                    |  2 +-
+ src/build_test.cc               | 12 +------
+ src/subprocess-posix.cc         |  4 +--
+ src/subprocess-win32.cc         |  2 +-
+ src/subprocess.h                |  2 +-
+ src/subprocess_test.cc          | 26 +++++++-------
+ src/tokenpool-gnu-make-posix.cc | 21 +++++------
+ src/tokenpool-gnu-make-win32.cc | 36 ++++++++++---------
+ src/tokenpool-gnu-make.cc       | 63 +++++++++++++++++----------------
+ src/tokenpool-gnu-make.h        |  6 ++--
+ src/tokenpool-none.cc           | 22 ------------
+ src/tokenpool.h                 |  2 +-
+ src/tokenpool_test.cc           |  8 ++---
+ 14 files changed, 94 insertions(+), 120 deletions(-)
+ delete mode 100644 src/tokenpool-none.cc
+
+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index 57ae548f5b..e2876fe413 100644
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -112,6 +112,7 @@ add_library(libninja OBJECT
+ 	src/state.cc
+ 	src/status.cc
+ 	src/string_piece_util.cc
++	src/tokenpool-gnu-make.cc
+ 	src/util.cc
+ 	src/version.cc
+ )
+@@ -123,9 +124,13 @@ if(WIN32)
+ 		src/msvc_helper_main-win32.cc
+ 		src/getopt.c
+ 		src/minidump-win32.cc
++		src/tokenpool-gnu-make-win32.cc
+ 	)
+ else()
+-	target_sources(libninja PRIVATE src/subprocess-posix.cc)
++	target_sources(libninja PRIVATE
++		src/subprocess-posix.cc
++		src/tokenpool-gnu-make-posix.cc
++	)
+ 	if(CMAKE_SYSTEM_NAME STREQUAL "OS400" OR CMAKE_SYSTEM_NAME STREQUAL "AIX")
+ 		target_sources(libninja PRIVATE src/getopt.c)
+ 	endif()
+@@ -204,6 +209,7 @@ if(BUILD_TESTING)
+     src/string_piece_util_test.cc
+     src/subprocess_test.cc
+     src/test.cc
++    src/tokenpool_test.cc
+     src/util_test.cc
+   )
+   if(WIN32)
+diff --git a/src/build.cc b/src/build.cc
+index 20c3bdc2a0..854df08c2a 100644
+--- a/src/build.cc
++++ b/src/build.cc
+@@ -467,7 +467,7 @@ struct RealCommandRunner : public CommandRunner {
+   // copy of config_.max_load_average; can be modified by TokenPool setup
+   double max_load_average_;
+   SubprocessSet subprocs_;
+-  TokenPool *tokens_;
++  TokenPool* tokens_;
+   map<const Subprocess*, Edge*> subproc_to_edge_;
+ };
+ 
+diff --git a/src/build_test.cc b/src/build_test.cc
+index dd41dfbe1d..8901c9518f 100644
+--- a/src/build_test.cc
++++ b/src/build_test.cc
+@@ -4098,7 +4098,7 @@ struct BuildTokenTest : public BuildTest {
+   void ExpectWaitForCommand(int count, ...);
+ 
+ private:
+-  void EnqueueBooleans(vector<bool>& booleans, int count, va_list ao);
++  void EnqueueBooleans(vector<bool>& booleans, int count, va_list ap);
+ };
+ 
+ void BuildTokenTest::SetUp() {
+@@ -4144,16 +4144,6 @@ void BuildTokenTest::EnqueueBooleans(vector<bool>& booleans, int count, va_list
+   }
+ }
+ 
+-TEST_F(BuildTokenTest, CompleteNoWork) {
+-  // plan should not execute anything
+-  string err;
+-
+-  EXPECT_TRUE(builder_.Build(&err));
+-  EXPECT_EQ("", err);
+-
+-  EXPECT_EQ(0u, token_command_runner_.commands_ran_.size());
+-}
+-
+ TEST_F(BuildTokenTest, DoNotAquireToken) {
+   // plan should execute one command
+   string err;
+diff --git a/src/subprocess-posix.cc b/src/subprocess-posix.cc
+index 74451b0be2..31839276c4 100644
+--- a/src/subprocess-posix.cc
++++ b/src/subprocess-posix.cc
+@@ -250,7 +250,7 @@ Subprocess *SubprocessSet::Add(const string& command, bool use_console) {
+ }
+ 
+ #ifdef USE_PPOLL
+-bool SubprocessSet::DoWork(struct TokenPool* tokens) {
++bool SubprocessSet::DoWork(TokenPool* tokens) {
+   vector<pollfd> fds;
+   nfds_t nfds = 0;
+ 
+@@ -315,7 +315,7 @@ bool SubprocessSet::DoWork(struct TokenPool* tokens) {
+ }
+ 
+ #else  // !defined(USE_PPOLL)
+-bool SubprocessSet::DoWork(struct TokenPool* tokens) {
++bool SubprocessSet::DoWork(TokenPool* tokens) {
+   fd_set set;
+   int nfds = 0;
+   FD_ZERO(&set);
+diff --git a/src/subprocess-win32.cc b/src/subprocess-win32.cc
+index ce3e2c20a4..2926e9a221 100644
+--- a/src/subprocess-win32.cc
++++ b/src/subprocess-win32.cc
+@@ -252,7 +252,7 @@ Subprocess *SubprocessSet::Add(const string& command, bool use_console) {
+   return subprocess;
+ }
+ 
+-bool SubprocessSet::DoWork(struct TokenPool* tokens) {
++bool SubprocessSet::DoWork(TokenPool* tokens) {
+   DWORD bytes_read;
+   Subprocess* subproc;
+   OVERLAPPED* overlapped;
+diff --git a/src/subprocess.h b/src/subprocess.h
+index 9ea67ea477..1ec78171e8 100644
+--- a/src/subprocess.h
++++ b/src/subprocess.h
+@@ -86,7 +86,7 @@ struct SubprocessSet {
+   ~SubprocessSet();
+ 
+   Subprocess* Add(const std::string& command, bool use_console = false);
+-  bool DoWork(struct TokenPool* tokens);
++  bool DoWork(TokenPool* tokens);
+   Subprocess* NextFinished();
+   void Clear();
+ 
+diff --git a/src/subprocess_test.cc b/src/subprocess_test.cc
+index f625963462..7b146f31be 100644
+--- a/src/subprocess_test.cc
++++ b/src/subprocess_test.cc
+@@ -35,7 +35,7 @@ const char* kSimpleCommand = "cmd /c dir \\";
+ const char* kSimpleCommand = "ls /";
+ #endif
+ 
+-struct TokenPoolTest : public TokenPool {
++struct TestTokenPool : public TokenPool {
+   bool Acquire()     { return false; }
+   void Reserve()     {}
+   void Release()     {}
+@@ -58,7 +58,7 @@ struct TokenPoolTest : public TokenPool {
+ 
+ struct SubprocessTest : public testing::Test {
+   SubprocessSet subprocs_;
+-  TokenPoolTest tokens_;
++  TestTokenPool tokens_;
+ };
+ 
+ }  // anonymous namespace
+@@ -73,7 +73,7 @@ TEST_F(SubprocessTest, BadCommandStderr) {
+     // Pretend we discovered that stderr was ready for writing.
+     subprocs_.DoWork(NULL);
+   }
+-  ASSERT_EQ(false, subprocs_.IsTokenAvailable());
++  ASSERT_FALSE(subprocs_.IsTokenAvailable());
+ 
+   EXPECT_EQ(ExitFailure, subproc->Finish());
+   EXPECT_NE("", subproc->GetOutput());
+@@ -89,7 +89,7 @@ TEST_F(SubprocessTest, NoSuchCommand) {
+     // Pretend we discovered that stderr was ready for writing.
+     subprocs_.DoWork(NULL);
+   }
+-  ASSERT_EQ(false, subprocs_.IsTokenAvailable());
++  ASSERT_FALSE(subprocs_.IsTokenAvailable());
+ 
+   EXPECT_EQ(ExitFailure, subproc->Finish());
+   EXPECT_NE("", subproc->GetOutput());
+@@ -109,7 +109,7 @@ TEST_F(SubprocessTest, InterruptChild) {
+   while (!subproc->Done()) {
+     subprocs_.DoWork(NULL);
+   }
+-  ASSERT_EQ(false, subprocs_.IsTokenAvailable());
++  ASSERT_FALSE(subprocs_.IsTokenAvailable());
+ 
+   EXPECT_EQ(ExitInterrupted, subproc->Finish());
+ }
+@@ -135,7 +135,7 @@ TEST_F(SubprocessTest, InterruptChildWithSigTerm) {
+   while (!subproc->Done()) {
+     subprocs_.DoWork(NULL);
+   }
+-  ASSERT_EQ(false, subprocs_.IsTokenAvailable());
++  ASSERT_FALSE(subprocs_.IsTokenAvailable());
+ 
+   EXPECT_EQ(ExitInterrupted, subproc->Finish());
+ }
+@@ -161,7 +161,7 @@ TEST_F(SubprocessTest, InterruptChildWithSigHup) {
+   while (!subproc->Done()) {
+     subprocs_.DoWork(NULL);
+   }
+-  ASSERT_EQ(false, subprocs_.IsTokenAvailable());
++  ASSERT_FALSE(subprocs_.IsTokenAvailable());
+ 
+   EXPECT_EQ(ExitInterrupted, subproc->Finish());
+ }
+@@ -190,7 +190,7 @@ TEST_F(SubprocessTest, Console) {
+     while (!subproc->Done()) {
+       subprocs_.DoWork(NULL);
+     }
+-    ASSERT_EQ(false, subprocs_.IsTokenAvailable());
++    ASSERT_FALSE(subprocs_.IsTokenAvailable());
+ 
+     EXPECT_EQ(ExitSuccess, subproc->Finish());
+   }
+@@ -206,7 +206,7 @@ TEST_F(SubprocessTest, SetWithSingle) {
+   while (!subproc->Done()) {
+     subprocs_.DoWork(NULL);
+   }
+-  ASSERT_EQ(false, subprocs_.IsTokenAvailable());
++  ASSERT_FALSE(subprocs_.IsTokenAvailable());
+   ASSERT_EQ(ExitSuccess, subproc->Finish());
+   ASSERT_NE("", subproc->GetOutput());
+ 
+@@ -243,7 +243,7 @@ TEST_F(SubprocessTest, SetWithMulti) {
+     ASSERT_GT(subprocs_.running_.size(), 0u);
+     subprocs_.DoWork(NULL);
+   }
+-  ASSERT_EQ(false, subprocs_.IsTokenAvailable());
++  ASSERT_FALSE(subprocs_.IsTokenAvailable());
+   ASSERT_EQ(0u, subprocs_.running_.size());
+   ASSERT_EQ(3u, subprocs_.finished_.size());
+ 
+@@ -278,7 +278,7 @@ TEST_F(SubprocessTest, SetWithLots) {
+   subprocs_.ResetTokenAvailable();
+   while (!subprocs_.running_.empty())
+     subprocs_.DoWork(NULL);
+-  ASSERT_EQ(false, subprocs_.IsTokenAvailable());
++  ASSERT_FALSE(subprocs_.IsTokenAvailable());
+   for (size_t i = 0; i < procs.size(); ++i) {
+     ASSERT_EQ(ExitSuccess, procs[i]->Finish());
+     ASSERT_NE("", procs[i]->GetOutput());
+@@ -298,7 +298,7 @@ TEST_F(SubprocessTest, ReadStdin) {
+   while (!subproc->Done()) {
+     subprocs_.DoWork(NULL);
+   }
+-  ASSERT_EQ(false, subprocs_.IsTokenAvailable());
++  ASSERT_FALSE(subprocs_.IsTokenAvailable());
+   ASSERT_EQ(ExitSuccess, subproc->Finish());
+   ASSERT_EQ(1u, subprocs_.finished_.size());
+ }
+@@ -322,7 +322,7 @@ TEST_F(SubprocessTest, TokenAvailable) {
+   subprocs_.DoWork(&tokens_);
+ #ifdef _WIN32
+   tokens_._token_available = false;
+-  // we need to loop here as we have no conrol where the token
++  // we need to loop here as we have no control where the token
+   // I/O completion post ends up in the queue
+   while (!subproc->Done() && !subprocs_.IsTokenAvailable()) {
+     subprocs_.DoWork(&tokens_);
+diff --git a/src/tokenpool-gnu-make-posix.cc b/src/tokenpool-gnu-make-posix.cc
+index 70d84bfff7..353bda226a 100644
+--- a/src/tokenpool-gnu-make-posix.cc
++++ b/src/tokenpool-gnu-make-posix.cc
+@@ -32,8 +32,8 @@ struct GNUmakeTokenPoolPosix : public GNUmakeTokenPool {
+ 
+   virtual int GetMonitorFd();
+ 
+-  virtual const char *GetEnv(const char *name) { return getenv(name); };
+-  virtual bool ParseAuth(const char *jobserver);
++  virtual const char* GetEnv(const char* name) { return getenv(name); };
++  virtual bool ParseAuth(const char* jobserver);
+   virtual bool AcquireToken();
+   virtual bool ReturnToken();
+ 
+@@ -64,9 +64,7 @@ bool GNUmakeTokenPoolPosix::CheckFd(int fd) {
+   if (fd < 0)
+     return false;
+   int ret = fcntl(fd, F_GETFD);
+-  if (ret < 0)
+-    return false;
+-  return true;
++  return ret >= 0;
+ }
+ 
+ int GNUmakeTokenPoolPosix::dup_rfd_ = -1;
+@@ -82,14 +80,13 @@ bool GNUmakeTokenPoolPosix::SetAlarmHandler() {
+   act.sa_handler = CloseDupRfd;
+   if (sigaction(SIGALRM, &act, &old_act_) < 0) {
+     perror("sigaction:");
+-    return(false);
+-  } else {
+-    restore_ = true;
+-    return(true);
++    return false;
+   }
++  restore_ = true;
++  return true;
+ }
+ 
+-bool GNUmakeTokenPoolPosix::ParseAuth(const char *jobserver) {
++bool GNUmakeTokenPoolPosix::ParseAuth(const char* jobserver) {
+   int rfd = -1;
+   int wfd = -1;
+   if ((sscanf(jobserver, "%*[^=]=%d,%d", &rfd, &wfd) == 2) &&
+@@ -195,9 +192,9 @@ bool GNUmakeTokenPoolPosix::ReturnToken() {
+ }
+ 
+ int GNUmakeTokenPoolPosix::GetMonitorFd() {
+-  return(rfd_);
++  return rfd_;
+ }
+ 
+-struct TokenPool *TokenPool::Get() {
++TokenPool* TokenPool::Get() {
+   return new GNUmakeTokenPoolPosix;
+ }
+diff --git a/src/tokenpool-gnu-make-win32.cc b/src/tokenpool-gnu-make-win32.cc
+index 2719f2c1fc..b2bb52fadb 100644
+--- a/src/tokenpool-gnu-make-win32.cc
++++ b/src/tokenpool-gnu-make-win32.cc
+@@ -14,7 +14,8 @@
+ 
+ #include "tokenpool-gnu-make.h"
+ 
+-// always include first to make sure other headers do the correct thing...
++// Always include this first.
++// Otherwise the other system headers don't work correctly under Win32
+ #include <windows.h>
+ 
+ #include <ctype.h>
+@@ -32,8 +33,8 @@ struct GNUmakeTokenPoolWin32 : public GNUmakeTokenPool {
+   virtual void WaitForTokenAvailability(HANDLE ioport);
+   virtual bool TokenIsAvailable(ULONG_PTR key);
+ 
+-  virtual const char *GetEnv(const char *name);
+-  virtual bool ParseAuth(const char *jobserver);
++  virtual const char* GetEnv(const char* name);
++  virtual bool ParseAuth(const char* jobserver);
+   virtual bool AcquireToken();
+   virtual bool ReturnToken();
+ 
+@@ -98,19 +99,19 @@ GNUmakeTokenPoolWin32::~GNUmakeTokenPoolWin32() {
+   }
+ }
+ 
+-const char *GNUmakeTokenPoolWin32::GetEnv(const char *name) {
++const char* GNUmakeTokenPoolWin32::GetEnv(const char* name) {
+   // getenv() does not work correctly together with tokenpool_tests.cc
+   static char buffer[MAX_PATH + 1];
+-  if (GetEnvironmentVariable("MAKEFLAGS", buffer, sizeof(buffer)) == 0)
++  if (GetEnvironmentVariable(name, buffer, sizeof(buffer)) == 0)
+     return NULL;
+-  return(buffer);
++  return buffer;
+ }
+ 
+-bool GNUmakeTokenPoolWin32::ParseAuth(const char *jobserver) {
++bool GNUmakeTokenPoolWin32::ParseAuth(const char* jobserver) {
+   // match "--jobserver-auth=gmake_semaphore_<INTEGER>..."
+-  const char *start = strchr(jobserver, '=');
++  const char* start = strchr(jobserver, '=');
+   if (start) {
+-    const char *end = start;
++    const char* end = start;
+     unsigned int len;
+     char c, *auth;
+ 
+@@ -119,14 +120,15 @@ bool GNUmakeTokenPoolWin32::ParseAuth(const char *jobserver) {
+         break;
+     len = end - start; // includes string terminator in count
+ 
+-    if ((len > 1) && ((auth = (char *)malloc(len)) != NULL)) {
++    if ((len > 1) && ((auth = (char*)malloc(len)) != NULL)) {
+       strncpy(auth, start + 1, len - 1);
+       auth[len - 1] = '\0';
+ 
+-      if ((semaphore_jobserver_ = OpenSemaphore(SEMAPHORE_ALL_ACCESS, /* Semaphore access setting */
+-                                                FALSE,                /* Child processes DON'T inherit */
+-                                                auth                  /* Semaphore name */
+-                                                )) != NULL) {
++      if ((semaphore_jobserver_ =
++           OpenSemaphore(SEMAPHORE_ALL_ACCESS, /* Semaphore access setting */
++                         FALSE,                /* Child processes DON'T inherit */
++                         auth                  /* Semaphore name */
++                        )) != NULL) {
+         free(auth);
+         return true;
+       }
+@@ -171,7 +173,7 @@ DWORD GNUmakeTokenPoolWin32::SemaphoreThread() {
+ }
+ 
+ DWORD WINAPI GNUmakeTokenPoolWin32::SemaphoreThreadWrapper(LPVOID param) {
+-  GNUmakeTokenPoolWin32 *This = (GNUmakeTokenPoolWin32 *) param;
++  GNUmakeTokenPoolWin32* This = (GNUmakeTokenPoolWin32*) param;
+   return This->SemaphoreThread();
+ }
+ 
+@@ -216,7 +218,7 @@ void GNUmakeTokenPoolWin32::WaitForTokenAvailability(HANDLE ioport) {
+ 
+ bool GNUmakeTokenPoolWin32::TokenIsAvailable(ULONG_PTR key) {
+   // alert child thread to break wait on token semaphore
+-  QueueUserAPC(&NoopAPCFunc, child_, (ULONG_PTR)NULL);
++  QueueUserAPC((PAPCFUNC)&NoopAPCFunc, child_, (ULONG_PTR)NULL);
+ 
+   // return true when GetQueuedCompletionStatus() returned our key
+   return key == (ULONG_PTR) this;
+@@ -232,6 +234,6 @@ void GNUmakeTokenPoolWin32::WaitForObject(HANDLE object) {
+     Win32Fatal("WaitForSingleObject");
+ }
+ 
+-struct TokenPool *TokenPool::Get() {
++TokenPool* TokenPool::Get() {
+   return new GNUmakeTokenPoolWin32;
+ }
+diff --git a/src/tokenpool-gnu-make.cc b/src/tokenpool-gnu-make.cc
+index 92ff611721..60e0552924 100644
+--- a/src/tokenpool-gnu-make.cc
++++ b/src/tokenpool-gnu-make.cc
+@@ -31,36 +31,37 @@ GNUmakeTokenPool::~GNUmakeTokenPool() {
+ bool GNUmakeTokenPool::Setup(bool ignore,
+                              bool verbose,
+                              double& max_load_average) {
+-  const char *value = GetEnv("MAKEFLAGS");
+-  if (value) {
+-    // GNU make <= 4.1
+-    const char *jobserver = strstr(value, "--jobserver-fds=");
++  const char* value = GetEnv("MAKEFLAGS");
++  if (!value)
++    return false;
 +
-+  // implicit token
-+  EXPECT_TRUE(tokens_->Acquire());
-+}
++  // GNU make <= 4.1
++  const char* jobserver = strstr(value, "--jobserver-fds=");
++  if (!jobserver)
+     // GNU make => 4.2
+-    if (!jobserver)
+-      jobserver = strstr(value, "--jobserver-auth=");
+-    if (jobserver) {
+-      LinePrinter printer;
+-
+-      if (ignore) {
+-        printer.PrintOnNewLine("ninja: warning: -jN forced on command line; ignoring GNU make jobserver.\n");
+-      } else {
+-        if (ParseAuth(jobserver)) {
+-          const char *l_arg = strstr(value, " -l");
+-          int load_limit = -1;
+-
+-          if (verbose) {
+-            printer.PrintOnNewLine("ninja: using GNU make jobserver.\n");
+-          }
+-
+-          // translate GNU make -lN to ninja -lN
+-          if (l_arg &&
+-              (sscanf(l_arg + 3, "%d ", &load_limit) == 1) &&
+-              (load_limit > 0)) {
+-            max_load_average = load_limit;
+-          }
+-
+-          return true;
++    jobserver = strstr(value, "--jobserver-auth=");
++  if (jobserver) {
++    LinePrinter printer;
++
++    if (ignore) {
++      printer.PrintOnNewLine("ninja: warning: -jN forced on command line; ignoring GNU make jobserver.\n");
++    } else {
++      if (ParseAuth(jobserver)) {
++        const char* l_arg = strstr(value, " -l");
++        int load_limit = -1;
++
++        if (verbose) {
++          printer.PrintOnNewLine("ninja: using GNU make jobserver.\n");
++        }
++
++        // translate GNU make -lN to ninja -lN
++        if (l_arg &&
++            (sscanf(l_arg + 3, "%d ", &load_limit) == 1) &&
++            (load_limit > 0)) {
++          max_load_average = load_limit;
+         }
++
++        return true;
+       }
+     }
+   }
+@@ -76,10 +77,10 @@ bool GNUmakeTokenPool::Acquire() {
+     // token acquired
+     available_++;
+     return true;
+-  } else {
+-    // no token available
+-    return false;
+   }
++
++  // no token available
++  return false;
+ }
+ 
+ void GNUmakeTokenPool::Reserve() {
+diff --git a/src/tokenpool-gnu-make.h b/src/tokenpool-gnu-make.h
+index d3852088e2..c94cca5e2d 100644
+--- a/src/tokenpool-gnu-make.h
++++ b/src/tokenpool-gnu-make.h
+@@ -17,7 +17,7 @@
+ // interface to GNU make token pool
+ struct GNUmakeTokenPool : public TokenPool {
+   GNUmakeTokenPool();
+-  virtual ~GNUmakeTokenPool();
++  ~GNUmakeTokenPool();
+ 
+   // token pool implementation
+   virtual bool Acquire();
+@@ -27,8 +27,8 @@ struct GNUmakeTokenPool : public TokenPool {
+   virtual bool Setup(bool ignore, bool verbose, double& max_load_average);
+ 
+   // platform specific implementation
+-  virtual const char *GetEnv(const char *name) = 0;
+-  virtual bool ParseAuth(const char *jobserver) = 0;
++  virtual const char* GetEnv(const char* name) = 0;
++  virtual bool ParseAuth(const char* jobserver) = 0;
+   virtual bool AcquireToken() = 0;
+   virtual bool ReturnToken() = 0;
+ 
+diff --git a/src/tokenpool-none.cc b/src/tokenpool-none.cc
+deleted file mode 100644
+index 613d16882d..0000000000
+--- a/src/tokenpool-none.cc
++++ /dev/null
+@@ -1,22 +0,0 @@
+-// Copyright 2016-2018 Google Inc. All Rights Reserved.
+-//
+-// Licensed under the Apache License, Version 2.0 (the "License");
+-// you may not use this file except in compliance with the License.
+-// You may obtain a copy of the License at
+-//
+-//     http://www.apache.org/licenses/LICENSE-2.0
+-//
+-// Unless required by applicable law or agreed to in writing, software
+-// distributed under the License is distributed on an "AS IS" BASIS,
+-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+-// See the License for the specific language governing permissions and
+-// limitations under the License.
+-
+-#include "tokenpool.h"
+-
+-#include <stdlib.h>
+-
+-// No-op TokenPool implementation
+-struct TokenPool *TokenPool::Get() {
+-  return NULL;
+-}
+diff --git a/src/tokenpool.h b/src/tokenpool.h
+index 1be8e1d5ce..931c22754d 100644
+--- a/src/tokenpool.h
++++ b/src/tokenpool.h
+@@ -38,5 +38,5 @@ struct TokenPool {
+ #endif
+ 
+   // returns NULL if token pool is not available
+-  static struct TokenPool *Get();
++  static TokenPool* Get();
+ };
+diff --git a/src/tokenpool_test.cc b/src/tokenpool_test.cc
+index 8d4fd7d33a..8d3061cb30 100644
+--- a/src/tokenpool_test.cc
++++ b/src/tokenpool_test.cc
+@@ -43,10 +43,10 @@ const double kLoadAverageDefault = -1.23456789;
+ 
+ struct TokenPoolTest : public testing::Test {
+   double load_avg_;
+-  TokenPool *tokens_;
++  TokenPool* tokens_;
+   char buf_[1024];
+ #ifdef _WIN32
+-  const char *semaphore_name_;
++  const char* semaphore_name_;
+   HANDLE semaphore_;
+ #else
+   int fds_[2];
+@@ -65,7 +65,7 @@ struct TokenPoolTest : public testing::Test {
+       ASSERT_TRUE(false);
+   }
+ 
+-  void CreatePool(const char *format, bool ignore_jobserver = false) {
++  void CreatePool(const char* format, bool ignore_jobserver = false) {
+     if (format) {
+       sprintf(buf_, format,
+ #ifdef _WIN32
+@@ -209,7 +209,7 @@ TEST_F(TokenPoolTest, TwoTokens) {
+   tokens_->Release();
+   EXPECT_TRUE(tokens_->Acquire());
+ 
+-  // release implict token - must return 2nd token back to jobserver
++  // release implicit token - must return 2nd token back to jobserver
+   tokens_->Release();
+   EXPECT_TRUE(tokens_->Acquire());
+