Dynamically load FFmpeg DLLs if present and --enable-video is on.

If any of the DLLs fail to load or are not present, video is disabled.

Review URL: http://codereview.chromium.org/24025

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@10376 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 63 insertions, 3 deletions

diff --git a/chrome/common/chrome_paths.cc b/chrome/common/chrome_paths.cc
index 0c16079..40f22ba 100644
--- a/chrome/common/chrome_paths.cc
+++ b/chrome/common/chrome_paths.cc
@@ -31,6 +31,17 @@ bool GetGearsPluginPathFromCommandLine(FilePath* path) {
 #endif
 }
 
+// Attempts to find the given FFmpeg library and stores the result in |path|.
+// Returns true if the library was found and exists, false otherwise.
+static bool GetFFmpegLibraryPath(FilePath* path,
+                                 const FilePath::StringType& library) {
+  // Assume FFmpeg DLLs are kept alongside chrome.dll.
+  if (!PathService::Get(base::DIR_MODULE, path))
+    return false;
+  *path = path->Append(library);
+  return file_util::PathExists(*path);
+}
+
 bool PathProvider(int key, FilePath* result) {
   // Some keys are just aliases...
   switch (key) {
@@ -149,6 +160,18 @@ bool PathProvider(int key, FilePath* result) {
         }
       }
       break;
+    case chrome::FILE_LIBAVCODEC:
+      if (!GetFFmpegLibraryPath(&cur, FILE_PATH_LITERAL("avcodec-52.dll")))
+        return false;
+      break;
+    case chrome::FILE_LIBAVFORMAT:
+      if (!GetFFmpegLibraryPath(&cur, FILE_PATH_LITERAL("avformat-52.dll")))
+        return false;
+      break;
+    case chrome::FILE_LIBAVUTIL:
+      if (!GetFFmpegLibraryPath(&cur, FILE_PATH_LITERAL("avutil-49.dll")))
+        return false;
+      break;
     // The following are only valid in the development environment, and
     // will fail if executed from an installed executable (because the
     // generated path won't exist).
diff --git a/chrome/common/chrome_paths.h b/chrome/common/chrome_paths.h
index 9300e99..dec6da9 100644
--- a/chrome/common/chrome_paths.h
+++ b/chrome/common/chrome_paths.h
@@ -32,6 +32,9 @@ enum {
   FILE_RECORDED_SCRIPT,  // full path to the script.log file that contains
                          // recorded browser events for playback.
   FILE_GEARS_PLUGIN,     // full path to the gears.dll plugin file.
+  FILE_LIBAVCODEC,       // full path to libavcodec media decoding library.
+  FILE_LIBAVFORMAT,      // full path to libavformat media parsing library.
+  FILE_LIBAVUTIL,        // full path to libavutil media utility library.
 
   // Valid only in development environment; TODO(darin): move these
   DIR_TEST_DATA,         // directory where unit test data resides
diff --git a/chrome/renderer/render_process.cc b/chrome/renderer/render_process.cc
index 8cec986..80ec5fb 100644
--- a/chrome/renderer/render_process.cc
+++ b/chrome/renderer/render_process.cc
@@ -29,6 +29,42 @@
 #include "chrome/renderer/render_view.h"
 #include "webkit/glue/webkit_glue.h"
 
+// Attempts to load FFmpeg before engaging the sandbox.  Returns true if all
+// libraries were loaded successfully, false otherwise.
+static bool LoadFFmpeg() {
+#if defined(OS_WIN)
+  int path_keys[] = {
+    chrome::FILE_LIBAVCODEC,
+    chrome::FILE_LIBAVFORMAT,
+    chrome::FILE_LIBAVUTIL
+  };
+  HMODULE libs[arraysize(path_keys)] = {NULL};
+  for (size_t i = 0; i < arraysize(path_keys); ++i) {
+    std::wstring path;
+    if (!PathService::Get(path_keys[i], &path))
+      break;
+    libs[i] = LoadLibrary(path.c_str());
+    if (!libs[i])
+      break;
+  }
+
+  // Check that we loaded all libraries successfully.
+  if (libs[arraysize(libs)-1])
+    return true;
+
+  // Free any loaded libraries if we weren't successful.
+  for (size_t i = 0; i < arraysize(libs) && libs[i] != NULL; ++i) {
+    FreeLibrary(libs[i]);
+  }
+  return false;
+#else
+  // TODO(port): Need to handle loading FFmpeg on non-Windows platforms.
+  NOTIMPLEMENTED();
+  return false;
+#endif
+}
+
+//-----------------------------------------------------------------------------
 
 RenderProcess::RenderProcess()
     : ChildProcess(new RenderThread()),
@@ -122,8 +158,7 @@ void RenderProcess::Init() {
 #endif
   }
 
-  if (command_line.HasSwitch(switches::kEnableVideo)) {
-    // TODO(scherkus): check for any DLL dependencies.
+  if (command_line.HasSwitch(switches::kEnableVideo) && LoadFFmpeg()) {
     webkit_glue::SetMediaPlayerAvailable(true);
   }
 }
@@ -269,4 +304,3 @@ void RenderProcess::ClearTransportDIBCache() {
     }
   }
 }
-