1 files changed, 213 insertions, 1 deletions

diff --git a/media/base/media_posix.cc b/media/base/media_posix.cc
index 664f9f8..331a143 100755..100644
--- a/media/base/media_posix.cc
+++ b/media/base/media_posix.cc
@@ -4,15 +4,227 @@
 
 #include "media/base/media.h"
 
+#include <string>
+
+#include <dlfcn.h>
+
+#include "base/file_path.h"
 #include "base/logging.h"
 #include "base/path_service.h"
+#include "media/filters/ffmpeg_common.h"
+
+// We create stub references to dynamically loaded functions in ffmpeg
+// for ease of linking.
+//
+// TODO(ajwong): We need to find a more maintainable way to have this work.
+// Also, this code should really be in the ffmpeg wrapper, and not here
+// in the media level.  The concept of "weak symbols" looks like it might
+// be promising, but I don't quite understand it yet.
+extern "C" {
+
+void (*avcodec_init_ptr)(void) = NULL;
+void avcodec_init(void) {
+  avcodec_init_ptr();
+}
+
+AVCodec* (*avcodec_find_decoder_ptr)(enum CodecID id) = NULL;
+AVCodec* avcodec_find_decoder(enum CodecID id) {
+  return avcodec_find_decoder_ptr(id);
+}
+
+int (*avcodec_thread_init_ptr)(AVCodecContext* s, int thread_count) = NULL;
+int avcodec_thread_init(AVCodecContext* s, int thread_count) {
+  return avcodec_thread_init_ptr(s, thread_count);
+}
+
+int (*avcodec_open_ptr)(AVCodecContext* avctx, AVCodec* codec) = NULL;
+int avcodec_open(AVCodecContext* avctx, AVCodec* codec) {
+  return avcodec_open_ptr(avctx, codec);
+}
+
+AVFrame* (*avcodec_alloc_frame_ptr)(void) = NULL;
+AVFrame* avcodec_alloc_frame(void) {
+  return avcodec_alloc_frame_ptr();
+}
+
+int (*avcodec_decode_audio2_ptr)(AVCodecContext* avctx, int16_t* samples,
+                                 int* frame_size_ptr, const uint8_t* buf,
+                                 int buf_size) = NULL;
+int avcodec_decode_audio2(AVCodecContext* avctx, int16_t* samples,
+                          int* frame_size_ptr,
+                          const uint8_t* buf, int buf_size) {
+
+  return avcodec_decode_audio2_ptr(avctx, samples, frame_size_ptr, buf, 
+                                   buf_size);
+}
+
+
+int (*avcodec_decode_video_ptr)(AVCodecContext* avctx, AVFrame* picture,
+                                int* got_picture_ptr, const uint8_t* buf,
+                                int buf_size) = NULL;
+int avcodec_decode_video(AVCodecContext* avctx, AVFrame* picture,
+                         int* got_picture_ptr, const uint8_t* buf,
+                         int buf_size) {
+  return avcodec_decode_video_ptr(avctx, picture, got_picture_ptr, buf,
+                                  buf_size);
+}
+
+
+void (*av_register_all_ptr)(void);
+void av_register_all(void) {
+  av_register_all_ptr();
+}
+
+int (*av_open_input_file_ptr)(AVFormatContext** ic_ptr, const char* filename,
+                              AVInputFormat* fmt, int buf_size,
+                              AVFormatParameters* ap) = NULL;
+int av_open_input_file(AVFormatContext** ic_ptr, const char* filename,
+                       AVInputFormat* fmt, int buf_size,
+                       AVFormatParameters* ap) {
+  return av_open_input_file_ptr(ic_ptr, filename, fmt, buf_size, ap);
+}
+
+int (*av_find_stream_info_ptr)(AVFormatContext* ic) = NULL;
+int av_find_stream_info(AVFormatContext* ic) {
+  return av_find_stream_info_ptr(ic);
+}
+
+int (*av_read_frame_ptr)(AVFormatContext* s, AVPacket* pkt) = NULL;
+int av_read_frame(AVFormatContext* s, AVPacket* pkt) {
+  return av_read_frame_ptr(s, pkt);
+}
+
+
+void* (*av_malloc_ptr)(unsigned int size) = NULL;
+void* av_malloc(unsigned int size) {
+  return av_malloc_ptr(size);
+}
+
+}  // extern "C"
+
 
 namespace media {
 
+namespace {
+
+enum FFmpegDSOKeys {
+  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.
+std::string GetDSOName(FFmpegDSOKeys dso_key) {
+  // TODO(ajwong): Do we want to lock to a specific ffmpeg version?
+  // TODO(port): These library names are incorrect for mac.  We need .dynlib
+  // suffixes.
+  switch (dso_key) {
+    case FILE_LIBAVCODEC:
+      return FILE_PATH_LITERAL("libavcodec.so.52");
+    case FILE_LIBAVFORMAT:
+      return FILE_PATH_LITERAL("libavformat.so.52");
+    case FILE_LIBAVUTIL:
+      return FILE_PATH_LITERAL("libavutil.so.50");
+    default:
+      LOG(DFATAL) << "Invalid DSO key requested: " << dso_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& module_dir) {
-  NOTIMPLEMENTED();
+  // TODO(ajwong): We need error resolution.
+  FFmpegDSOKeys path_keys[] = {
+    FILE_LIBAVCODEC,
+    FILE_LIBAVFORMAT,
+    FILE_LIBAVUTIL
+  };
+  void* libs[arraysize(path_keys)] = {};
+  for (size_t i = 0; i < arraysize(path_keys); ++i) {
+    FilePath path = module_dir.Append(GetDSOName(path_keys[i]));
+    libs[i] = dlopen(path.value().c_str(), RTLD_LAZY);
+    if (!libs[i])
+      break;
+  }
+
+  // Check that we loaded all libraries successfully.  We only need to check the
+  // last array element because the loop above breaks on any failure.
+  if (libs[arraysize(libs)-1] == NULL) {
+    // Free any loaded libraries if we weren't successful.
+    for (size_t i = 0; i < arraysize(libs) && libs[i] != NULL; ++i) {
+      dlclose(libs[i]);
+      libs[i] = NULL;  // Just to be safe.
+    }
+    return false;
+  }
+
+  // TODO(ajwong): Extract this to somewhere saner, and hopefully
+  // autogenerate the bindings from the .def files.  Having all this
+  // code here is incredibly ugly.
+  avcodec_init_ptr =
+      reinterpret_cast<void(*)(void)>(
+          dlsym(libs[FILE_LIBAVCODEC], "avcodec_init"));
+  avcodec_find_decoder_ptr =
+      reinterpret_cast<AVCodec* (*)(enum CodecID)>(
+          dlsym(libs[FILE_LIBAVCODEC], "avcodec_find_decoder"));
+  avcodec_thread_init_ptr =
+      reinterpret_cast<int (*)(AVCodecContext*, int)>(
+          dlsym(libs[FILE_LIBAVCODEC], "avcodec_thread_init"));
+  avcodec_open_ptr =
+      reinterpret_cast<int (*)(AVCodecContext*, AVCodec*)>(
+          dlsym(libs[FILE_LIBAVCODEC], "avcodec_open"));
+  avcodec_alloc_frame_ptr =
+      reinterpret_cast<AVFrame* (*)(void)>(
+          dlsym(libs[FILE_LIBAVCODEC], "avcodec_alloc_frame"));
+  avcodec_decode_audio2_ptr =
+      reinterpret_cast<int (*)(AVCodecContext*, int16_t*, int*,
+                               const uint8_t*, int)>(
+          dlsym(libs[FILE_LIBAVCODEC], "avcodec_decode_audio2"));
+  avcodec_decode_video_ptr =
+      reinterpret_cast<int (*)(AVCodecContext*, AVFrame*, int*,
+                               const uint8_t*, int)>(
+          dlsym(libs[FILE_LIBAVCODEC], "avcodec_decode_video"));
+
+  av_register_all_ptr =
+      reinterpret_cast<void(*)(void)>(
+          dlsym(libs[FILE_LIBAVFORMAT], "av_register_all"));
+  av_open_input_file_ptr =
+      reinterpret_cast<int (*)(AVFormatContext**, const char*,
+                               AVInputFormat*, int,
+                               AVFormatParameters*)>(
+          dlsym(libs[FILE_LIBAVFORMAT], "av_open_input_file"));
+  av_find_stream_info_ptr =
+      reinterpret_cast<int (*)(AVFormatContext*)>(
+          dlsym(libs[FILE_LIBAVFORMAT], "av_find_stream_info"));
+  av_read_frame_ptr =
+      reinterpret_cast<int (*)(AVFormatContext*, AVPacket*)>(
+          dlsym(libs[FILE_LIBAVFORMAT], "av_read_frame"));
+
+  av_malloc_ptr =
+      reinterpret_cast<void* (*)(unsigned int)>(
+          dlsym(libs[FILE_LIBAVUTIL], "av_malloc"));
+
+  // Check that all the symbols were loaded correctly before returning true.
+  if (avcodec_init_ptr &&
+      avcodec_find_decoder_ptr &&
+      avcodec_thread_init_ptr &&
+      avcodec_open_ptr &&
+      avcodec_alloc_frame_ptr &&
+      avcodec_decode_audio2_ptr &&
+      avcodec_decode_video_ptr &&
+
+      av_register_all_ptr &&
+      av_open_input_file_ptr &&
+      av_find_stream_info_ptr &&
+      av_read_frame_ptr &&
+
+      av_malloc_ptr) {
+    return true;
+  }
+
   return false;
 }