Generate shim headers for libpng

BUG=165264

Review URL: https://codereview.chromium.org/11470020

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@173618 0039d316-1c4b-4281-b951-d872f2087c98

7 files changed, 123 insertions, 17 deletions

diff --git a/build/gyp_chromium b/build/gyp_chromium
index 499fa5c..ee5b3f3 100755
--- a/build/gyp_chromium
+++ b/build/gyp_chromium
@@ -21,6 +21,7 @@ sys.path.insert(0, os.path.join(chrome_src, 'tools', 'gyp', 'pylib'))
 import gyp
 
 # Add paths so that pymod_do_main(...) can import files.
+sys.path.insert(1, os.path.join(chrome_src, 'tools', 'generate_shim_headers'))
 sys.path.insert(1, os.path.join(chrome_src, 'tools', 'grit'))
 sys.path.insert(1, os.path.join(chrome_src, 'chrome', 'tools', 'build'))
 sys.path.insert(1, os.path.join(chrome_src, 'native_client', 'build'))
diff --git a/build/shim_headers.gypi b/build/shim_headers.gypi
new file mode 100644
index 0000000..cf0914d
--- /dev/null
+++ b/build/shim_headers.gypi
@@ -0,0 +1,45 @@
+# Copyright (c) 2012 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# This file is meant to be included into a target to handle shim headers
+# in a consistent manner. To use this the following variables need to be
+# defined:
+#   headers_root_path: string: path to directory containing headers
+#   header_filenames: list: list of header file names
+
+{
+  'variables': {
+    'shim_headers_path': '<(INTERMEDIATE_DIR)/shim_headers',
+  },
+  'direct_dependent_settings': {
+    'include_dirs+': [
+      '<(shim_headers_path)',
+    ],
+  },
+  'actions': [
+    {
+      'variables': {
+        'generator_path': '<(DEPTH)/tools/generate_shim_headers/generate_shim_headers.py',
+        'generator_args': [
+          '--headers-root', '<(headers_root_path)',
+          '--output-directory', '<(shim_headers_path)',
+          '<@(header_filenames)',
+        ],
+      },
+      'action_name': 'generate_<(_target_name)_shim_headers',
+      'inputs': [
+        '<(generator_path)',
+      ],
+      'outputs': [
+        '<!@pymod_do_main(generate_shim_headers <@(generator_args) --outputs)',
+      ],
+      'action': ['python',
+                 '<(generator_path)',
+                 '<@(generator_args)',
+                 '--generate',
+      ],
+      'message': 'Generating <(_target_name) shim headers.',
+    },
+  ],
+}
diff --git a/third_party/libpng/libpng.gyp b/third_party/libpng/libpng.gyp
index 634c0e3..2a20b6b 100644
--- a/third_party/libpng/libpng.gyp
+++ b/third_party/libpng/libpng.gyp
@@ -109,9 +109,6 @@
             'cflags': [
               '<!@(<(pkg-config) --cflags libpng)',
             ],
-            'defines': [
-              'USE_SYSTEM_LIBPNG',
-            ],
           },
           'link_settings': {
             'ldflags': [
@@ -121,6 +118,16 @@
               '<!@(<(pkg-config) --libs-only-l libpng)',
             ],
           },
+          'variables': {
+            'headers_root_path': '.',
+            'header_filenames': [
+              'png.h',
+              'pngconf.h',
+            ],
+          },
+          'includes': [
+            '../../build/shim_headers.gypi',
+          ],
         },
       ],
     }],
diff --git a/tools/generate_shim_headers/generate_shim_headers.py b/tools/generate_shim_headers/generate_shim_headers.py
new file mode 100755
index 0000000..068a2ac
--- /dev/null
+++ b/tools/generate_shim_headers/generate_shim_headers.py
@@ -0,0 +1,66 @@
+#!/usr/bin/env python
+# Copyright (c) 2012 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""
+Generates shim headers that mirror the directory structure of bundled headers,
+but just forward to the system ones.
+
+This allows seamless compilation against system headers with no changes
+to our source code.
+"""
+
+
+import optparse
+import os.path
+import sys
+
+
+SHIM_TEMPLATE = """
+#if defined(OFFICIAL_BUILD)
+#error shim headers must not be used in official builds!
+#endif
+
+#include <%s>
+"""
+
+
+def GeneratorMain(argv):
+  parser = optparse.OptionParser()
+  parser.add_option('--headers-root')
+  parser.add_option('--output-directory')
+  parser.add_option('--outputs', action='store_true')
+  parser.add_option('--generate', action='store_true')
+
+  options, args = parser.parse_args(argv)
+
+  if not options.headers_root:
+    parser.error('Missing --headers-root parameter.')
+  if not options.output_directory:
+    parser.error('Missing --output-directory parameter.')
+  if not args:
+    parser.error('Missing arguments - header file names.')
+
+  source_tree_root = os.path.abspath(
+    os.path.join(os.path.dirname(__file__), '..', '..'))
+
+  target_directory = os.path.join(
+    options.output_directory,
+    os.path.relpath(options.headers_root, source_tree_root))
+  if options.generate and not os.path.exists(target_directory):
+    os.makedirs(target_directory)
+  for header_filename in args:
+    if options.outputs:
+      yield os.path.join(target_directory, header_filename)
+    if options.generate:
+      with open(os.path.join(target_directory, header_filename), 'w') as f:
+        f.write(SHIM_TEMPLATE % header_filename)
+
+
+def DoMain(argv):
+  return '\n'.join(GeneratorMain(argv))
+
+
+if __name__ == '__main__':
+  DoMain(sys.argv[1:])
diff --git a/ui/gfx/codec/png_codec.cc b/ui/gfx/codec/png_codec.cc
index 474fbc9..e0dc4c6 100644
--- a/ui/gfx/codec/png_codec.cc
+++ b/ui/gfx/codec/png_codec.cc
@@ -14,11 +14,7 @@
 #include "third_party/skia/include/core/SkColorPriv.h"
 
 extern "C" {
-#if defined(USE_SYSTEM_LIBPNG)
-#include <png.h>
-#else
 #include "third_party/libpng/png.h"
-#endif
 
 #if defined(USE_SYSTEM_ZLIB)
 #include <zlib.h>
diff --git a/ui/gfx/codec/png_codec_unittest.cc b/ui/gfx/codec/png_codec_unittest.cc
index 83f535e..ef21d38 100644
--- a/ui/gfx/codec/png_codec_unittest.cc
+++ b/ui/gfx/codec/png_codec_unittest.cc
@@ -2,17 +2,12 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#if defined(USE_SYSTEM_LIBPNG)
-#include <png.h>
-#else
-#include "third_party/libpng/png.h"
-#endif
-
 #include <algorithm>
 #include <cmath>
 
 #include "base/logging.h"
 #include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/libpng/png.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/skia/include/core/SkColorPriv.h"
 #include "third_party/skia/include/core/SkUnPreMultiply.h"
diff --git a/webkit/support/webkit_support_gfx.cc b/webkit/support/webkit_support_gfx.cc
index 1471e29..1da7a34 100644
--- a/webkit/support/webkit_support_gfx.cc
+++ b/webkit/support/webkit_support_gfx.cc
@@ -9,11 +9,7 @@
 #include <string.h>
 
 extern "C" {
-#if defined(USE_SYSTEM_LIBPNG)
-#include <png.h>
-#else
 #include "third_party/libpng/png.h"
-#endif
 
 #if defined(USE_SYSTEM_ZLIB)
 #include <zlib.h>