From 6a036a5c8c7613e888fad39d92fc3fd84a96fbc7 Mon Sep 17 00:00:00 2001
From: "zhanyong.wan" <zhanyong.wan@861a406c-534a-0410-8894-cb66d6ee9925>
Date: Thu, 28 Feb 2013 23:46:07 +0000
Subject: Fixes a nasty issue in gtest's template instantiation.

---
 include/gtest/gtest-message.h | 72 +++++++++++++++++++++++++++----------------
 1 file changed, 46 insertions(+), 26 deletions(-)

(limited to 'include/gtest/gtest-message.h')

diff --git a/include/gtest/gtest-message.h b/include/gtest/gtest-message.h
index 6336b4a9..fe879bca 100644
--- a/include/gtest/gtest-message.h
+++ b/include/gtest/gtest-message.h
@@ -48,8 +48,11 @@
 
 #include <limits>
 
-#include "gtest/internal/gtest-string.h"
-#include "gtest/internal/gtest-internal.h"
+#include "gtest/internal/gtest-port.h"
+
+// Ensures that there is at least one operator<< in the global namespace.
+// See Message& operator<<(...) below for why.
+void operator<<(const testing::internal::Secret&, int);
 
 namespace testing {
 
@@ -87,15 +90,7 @@ class GTEST_API_ Message {
 
  public:
   // Constructs an empty Message.
-  // We allocate the stringstream separately because otherwise each use of
-  // ASSERT/EXPECT in a procedure adds over 200 bytes to the procedure's
-  // stack frame leading to huge stack frames in some cases; gcc does not reuse
-  // the stack space.
-  Message() : ss_(new ::std::stringstream) {
-    // By default, we want there to be enough precision when printing
-    // a double to a Message.
-    *ss_ << std::setprecision(std::numeric_limits<double>::digits10 + 2);
-  }
+  Message();
 
   // Copy constructor.
   Message(const Message& msg) : ss_(new ::std::stringstream) {  // NOLINT
@@ -118,7 +113,22 @@ class GTEST_API_ Message {
   // Streams a non-pointer value to this object.
   template <typename T>
   inline Message& operator <<(const T& val) {
-    ::GTestStreamToHelper(ss_.get(), val);
+    // Some libraries overload << for STL containers.  These
+    // overloads are defined in the global namespace instead of ::std.
+    //
+    // C++'s symbol lookup rule (i.e. Koenig lookup) says that these
+    // overloads are visible in either the std namespace or the global
+    // namespace, but not other namespaces, including the testing
+    // namespace which Google Test's Message class is in.
+    //
+    // To allow STL containers (and other types that has a << operator
+    // defined in the global namespace) to be used in Google Test
+    // assertions, testing::Message must access the custom << operator
+    // from the global namespace.  With this using declaration,
+    // overloads of << defined in the global namespace and those
+    // visible via Koenig lookup are both exposed in this function.
+    using ::operator <<;
+    *ss_ << val;
     return *this;
   }
 
@@ -140,7 +150,7 @@ class GTEST_API_ Message {
     if (pointer == NULL) {
       *ss_ << "(null)";
     } else {
-      ::GTestStreamToHelper(ss_.get(), pointer);
+      *ss_ << pointer;
     }
     return *this;
   }
@@ -164,12 +174,8 @@ class GTEST_API_ Message {
 
   // These two overloads allow streaming a wide C string to a Message
   // using the UTF-8 encoding.
-  Message& operator <<(const wchar_t* wide_c_str) {
-    return *this << internal::String::ShowWideCString(wide_c_str);
-  }
-  Message& operator <<(wchar_t* wide_c_str) {
-    return *this << internal::String::ShowWideCString(wide_c_str);
-  }
+  Message& operator <<(const wchar_t* wide_c_str);
+  Message& operator <<(wchar_t* wide_c_str);
 
 #if GTEST_HAS_STD_WSTRING
   // Converts the given wide string to a narrow string using the UTF-8
@@ -187,9 +193,7 @@ class GTEST_API_ Message {
   // Each '\0' character in the buffer is replaced with "\\0".
   //
   // INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
-  std::string GetString() const {
-    return internal::StringStreamToString(ss_.get());
-  }
+  std::string GetString() const;
 
  private:
 
@@ -199,16 +203,20 @@ class GTEST_API_ Message {
   // decide between class template specializations for T and T*, so a
   // tr1::type_traits-like is_pointer works, and we can overload on that.
   template <typename T>
-  inline void StreamHelper(internal::true_type /*dummy*/, T* pointer) {
+  inline void StreamHelper(internal::true_type /*is_pointer*/, T* pointer) {
     if (pointer == NULL) {
       *ss_ << "(null)";
     } else {
-      ::GTestStreamToHelper(ss_.get(), pointer);
+      *ss_ << pointer;
     }
   }
   template <typename T>
-  inline void StreamHelper(internal::false_type /*dummy*/, const T& value) {
-    ::GTestStreamToHelper(ss_.get(), value);
+  inline void StreamHelper(internal::false_type /*is_pointer*/,
+                           const T& value) {
+    // See the comments in Message& operator <<(const T&) above for why
+    // we need this using statement.
+    using ::operator <<;
+    *ss_ << value;
   }
 #endif  // GTEST_OS_SYMBIAN
 
@@ -225,6 +233,18 @@ inline std::ostream& operator <<(std::ostream& os, const Message& sb) {
   return os << sb.GetString();
 }
 
+namespace internal {
+
+// Converts a streamable value to an std::string.  A NULL pointer is
+// converted to "(null)".  When the input value is a ::string,
+// ::std::string, ::wstring, or ::std::wstring object, each NUL
+// character in it is replaced with "\\0".
+template <typename T>
+std::string StreamableToString(const T& streamable) {
+  return (Message() << streamable).GetString();
+}
+
+}  // namespace internal
 }  // namespace testing
 
 #endif  // GTEST_INCLUDE_GTEST_GTEST_MESSAGE_H_
-- 
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