API refactor to separate cffi declarations

* Moved to structure similar to OpenTLS
* api modified to load the cffi modules
* cffi verify methods broken out
* Jarret Raim and I pair programmed this

5 files changed, 104 insertions, 30 deletions

diff --git a/AUTHORS.rst b/AUTHORS.rst
index 9d499dc7..1aa37e48 100644
--- a/AUTHORS.rst
+++ b/AUTHORS.rst
@@ -7,4 +7,5 @@ AUTHORS
 * Laurens Van Houtven <_@lvh.io>
 * Christian Heimes <christian@python.org>
 * Paul Kehrer <paul.l.kehrer@gmail.com>
+* Jarret Raim <jarito@gmail.com>
 
diff --git a/cryptography/bindings/openssl/api.py b/cryptography/bindings/openssl/api.py
index 917c1846..f2369406 100644
--- a/cryptography/bindings/openssl/api.py
+++ b/cryptography/bindings/openssl/api.py
@@ -22,40 +22,51 @@ class API(object):
     """
     OpenSSL API wrapper.
     """
+    # TODO: is there a way to enumerate the files in the cffi module
+    # rather than hardcode them?
+    _modules = [
+        'evp',
+        'opensslv',
+    ]
 
     def __init__(self):
-        ffi = cffi.FFI()
-        self._populate_ffi(ffi)
-        self._ffi = ffi
-        self._lib = ffi.verify("""
-        #include <openssl/evp.h>
-        #include <openssl/opensslv.h>
-        """)
+        self._ffi = cffi.FFI()
+        self.INCLUDES, self.TYPES, self.FUNCTIONS = [], [], []
+        self._import()
+        self._define()
+        self._verify()
+
         self._lib.OpenSSL_add_all_algorithms()
 
-    def _populate_ffi(self, ffi):
-        ffi.cdef("""
-        typedef struct {
-            ...;
-        } EVP_CIPHER_CTX;
-        typedef ... EVP_CIPHER;
-        typedef ... ENGINE;
-
-        static char *const OPENSSL_VERSION_TEXT;
-
-        void OpenSSL_add_all_algorithms();
-
-        const EVP_CIPHER *EVP_get_cipherbyname(const char *);
-        int EVP_EncryptInit_ex(EVP_CIPHER_CTX *, const EVP_CIPHER *,
-                               ENGINE *, unsigned char *, unsigned char *);
-        int EVP_CIPHER_CTX_set_padding(EVP_CIPHER_CTX *, int);
-        int EVP_EncryptUpdate(EVP_CIPHER_CTX *, unsigned char *, int *,
-                              unsigned char *, int);
-        int EVP_EncryptFinal_ex(EVP_CIPHER_CTX *, unsigned char *, int *);
-        int EVP_CIPHER_CTX_cleanup(EVP_CIPHER_CTX *);
-        const EVP_CIPHER *EVP_CIPHER_CTX_cipher(const EVP_CIPHER_CTX *);
-        int EVP_CIPHER_block_size(const EVP_CIPHER *);
-        """)
+    def _import(self):
+        "import all library definitions"
+        for name in self._modules:
+            module = __import__('cryptography.bindings.openssl.cffi.' + name,
+                                fromlist=['*'])
+            self._import_definitions(module, 'INCLUDES')
+            self._import_definitions(module, 'TYPES')
+            self._import_definitions(module, 'FUNCTIONS')
+
+    def _import_definitions(self, module, name):
+        "import defintions named definitions from module"
+        container = getattr(self, name)
+        for definition in getattr(module, name, ()):
+            if definition not in container:
+                container.append(definition)
+
+    def _define(self):
+        "parse function definitions"
+        for typedef in self.TYPES:
+            self._ffi.cdef(typedef)
+        for function in self.FUNCTIONS:
+            self._ffi.cdef(function)
+
+    def _verify(self):
+        "load openssl, create function attributes"
+        self._lib = self._ffi.verify(
+            source="\n".join(self.INCLUDES),
+            libraries=['crypto']
+        )
 
     def openssl_version_text(self):
         """
diff --git a/cryptography/bindings/openssl/cffi/__init__.py b/cryptography/bindings/openssl/cffi/__init__.py
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/cryptography/bindings/openssl/cffi/__init__.py
diff --git a/cryptography/bindings/openssl/cffi/evp.py b/cryptography/bindings/openssl/cffi/evp.py
new file mode 100644
index 00000000..be72a265
--- /dev/null
+++ b/cryptography/bindings/openssl/cffi/evp.py
@@ -0,0 +1,39 @@
+# 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.
+
+INCLUDES = [
+    "#include <openssl/evp.h>"
+]
+
+TEARDOWN = [
+]
+
+TYPES = [
+    "typedef struct { ...; } EVP_CIPHER_CTX;",
+    "typedef ... EVP_CIPHER;",
+    "typedef ... ENGINE;",
+]
+
+FUNCTIONS = [
+    "void OpenSSL_add_all_algorithms();",
+    "const EVP_CIPHER *EVP_get_cipherbyname(const char *);",
+    "int EVP_EncryptInit_ex(EVP_CIPHER_CTX *, const EVP_CIPHER *, \
+                            ENGINE *, unsigned char *, unsigned char *);",
+    "int EVP_CIPHER_CTX_set_padding(EVP_CIPHER_CTX *, int);",
+    "int EVP_EncryptUpdate(EVP_CIPHER_CTX *, unsigned char *, int *, \
+                           unsigned char *, int);",
+    "int EVP_EncryptFinal_ex(EVP_CIPHER_CTX *, unsigned char *, int *);",
+    "int EVP_CIPHER_CTX_cleanup(EVP_CIPHER_CTX *);",
+    "const EVP_CIPHER *EVP_CIPHER_CTX_cipher(const EVP_CIPHER_CTX *);",
+    "int EVP_CIPHER_block_size(const EVP_CIPHER *);",
+]
diff --git a/cryptography/bindings/openssl/cffi/opensslv.py b/cryptography/bindings/openssl/cffi/opensslv.py
new file mode 100644
index 00000000..33212b89
--- /dev/null
+++ b/cryptography/bindings/openssl/cffi/opensslv.py
@@ -0,0 +1,23 @@
+# 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.
+
+INCLUDES = [
+    "#include <openssl/opensslv.h>"
+]
+
+TYPES = [
+    "static char *const OPENSSL_VERSION_TEXT;"
+]
+
+FUNCTIONS = [
+]