Move the ffmpeg loading function into media library.

This will allow us to hide the platform specific library loading code from the main chrome code.

Review URL: http://codereview.chromium.org/69027

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@13991 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 114 insertions, 0 deletions

diff --git a/media/base/media.h b/media/base/media.h
new file mode 100755
index 0000000..171d4e8
--- /dev/null
+++ b/media/base/media.h
@@ -0,0 +1,26 @@
+// Copyright (c) 2009 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.
+
+// Contains code that should be used for initializing, or querying the state
+// of the media library as a whole.
+
+#ifndef MEDIA_BASE_MEDIA_H_
+#define MEDIA_BASE_MEDIA_H_
+
+class FilePath;
+
+namespace media {
+
+// Attempts to initialize the media library (loading DLLs, DSOs, etc.).
+// If |module_dir| is the emptry string, then the system default library paths
+// are searched for the dynamic libraries.  If a |module_dir| is provided, then
+// only the specified |module_dir| will be searched for the dynamic libraries.
+//
+// Returns true if everything was successfully initialized, false otherwise.
+bool InitializeMediaLibrary(const FilePath& module_dir);
+
+}  // namespace media
+
+#endif  // MEDIA_BASE_MEDIA_H_
+
diff --git a/media/base/media_posix.cc b/media/base/media_posix.cc
new file mode 100755
index 0000000..664f9f8
--- /dev/null
+++ b/media/base/media_posix.cc
@@ -0,0 +1,19 @@
+// Copyright (c) 2009 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.
+
+#include "media/base/media.h"
+
+#include "base/logging.h"
+#include "base/path_service.h"
+
+namespace media {
+
+// Attempts to initialize the media library (loading DLLs, DSOs, etc.).
+// Returns true if everything was successfully initialized, false otherwise.
+bool InitializeMediaLibrary(const FilePath& module_dir) {
+  NOTIMPLEMENTED();
+  return false;
+}
+
+}  // namespace media
diff --git a/media/base/media_win.cc b/media/base/media_win.cc
new file mode 100755
index 0000000..c0219d9
--- /dev/null
+++ b/media/base/media_win.cc
@@ -0,0 +1,69 @@
+// Copyright (c) 2009 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.
+
+#include "media/base/media.h"
+
+#include <windows.h>
+
+#include "base/file_path.h"
+#include "base/logging.h"
+#include "base/path_service.h"
+
+namespace media {
+
+namespace {
+
+enum FFmpegDLLKeys {
+  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.
+};
+
+// Retrieves the DLLName for the given key.
+FilePath::CharType* GetDLLName(FFmpegDLLKeys dll_key) {
+  // TODO(ajwong): Do we want to lock to a specific ffmpeg version?
+  switch (dll_key) {
+    case FILE_LIBAVCODEC:
+      return FILE_PATH_LITERAL("avcodec-52.dll");
+    case FILE_LIBAVFORMAT:
+      return FILE_PATH_LITERAL("avcodec-52.dll");
+    case FILE_LIBAVUTIL:
+      return FILE_PATH_LITERAL("avutil-50.dll");
+    default:
+      LOG(DFATAL) << "Invalid DLL key requested: " << dll_key;
+      return FILE_PATH_LITERAL("");
+  }
+}
+
+}  // namespace
+
+// Attempts to initialize the media library (loading DLLs, DSOs, etc.).
+// Returns true if everything was successfully initialized, false otherwise.
+bool InitializeMediaLibrary(const FilePath& base_path) {
+  FFmpegDLLKeys path_keys[] = {
+    media::FILE_LIBAVCODEC,
+    media::FILE_LIBAVFORMAT,
+    media::FILE_LIBAVUTIL
+  };
+  HMODULE libs[arraysize(path_keys)] = {NULL};
+  for (size_t i = 0; i < arraysize(path_keys); ++i) {
+    FilePath path = base_path.Append(GetDLLName(path_keys[i]));
+    libs[i] = LoadLibrary(path.value().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]);
+    libs[i] = NULL;  // Just to be safe.
+  }
+  return false;
+}
+
+}  // namespace media