Bug 1223333: [ffmpeg] Do not rely on library name to determine the libavcodec's version. r=kentuckyfriedtakahe

Also uses portable way to dynamically open libraries.

dom/media/platforms/ffmpeg/FFmpegDataDecoder.cpp

@@ -13,7 +13,7 @@
 #include "FFmpegLog.h"
 #include "FFmpegDataDecoder.h"
 #include "prsystem.h"
-#include "FFmpegDecoderModule.h"
+#include "FFmpegRuntimeLinker.h"
 
 namespace mozilla
 {
@@ -89,7 +89,7 @@ FFmpegDataDecoder<LIBAV_VER>::InitDecoder()
 
   // FFmpeg takes this as a suggestion for what format to use for audio samples.
   uint32_t major, minor;
-  FFmpegDecoderModule<LIBAV_VER>::GetVersion(major, minor);
+  FFmpegRuntimeLinker::GetVersion(major, minor);
   // LibAV 0.8 produces rubbish float interlaved samples, request 16 bits audio.
   mCodecContext->request_sample_fmt = major == 53 && minor <= 34 ?
     AV_SAMPLE_FMT_S16 : AV_SAMPLE_FMT_FLT;

dom/media/platforms/ffmpeg/FFmpegDecoderModule.h

@@ -26,15 +26,6 @@ public:
     return pdm.forget();
   }
 
-  static bool
-  GetVersion(uint32_t& aMajor, uint32_t& aMinor)
-  {
-    uint32_t version = avcodec_version();
-    aMajor = (version >> 16) & 0xff;
-    aMinor = (version >> 8) & 0xff;
-    return true;
-  }
-
   FFmpegDecoderModule() {}
   virtual ~FFmpegDecoderModule() {}
 

dom/media/platforms/ffmpeg/FFmpegFunctionList.h

@@ -16,11 +16,9 @@ AV_FUNC(avcodec_alloc_context3, 0)
 AV_FUNC(avcodec_get_edge_width, 0)
 AV_FUNC(avcodec_open2, 0)
 AV_FUNC(av_init_packet, 0)
-AV_FUNC(av_dict_get, 0)
 AV_FUNC(av_parser_init, 0)
 AV_FUNC(av_parser_close, 0)
 AV_FUNC(av_parser_parse2, 0)
-AV_FUNC(avcodec_version, 0)
 AV_FUNC(avcodec_register_all, 0)
 
 /* libavutil */

dom/media/platforms/ffmpeg/FFmpegRuntimeLinker.cpp

@@ -4,14 +4,11 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-#include <dlfcn.h>
-
 #include "FFmpegRuntimeLinker.h"
 #include "mozilla/ArrayUtils.h"
 #include "FFmpegLog.h"
 #include "mozilla/Preferences.h"
-
-#define NUM_ELEMENTS(X) (sizeof(X) / sizeof((X)[0]))
+#include "prlink.h"
 
 namespace mozilla
 {
@@ -19,35 +16,33 @@ namespace mozilla
 FFmpegRuntimeLinker::LinkStatus FFmpegRuntimeLinker::sLinkStatus =
   LinkStatus_INIT;
 
-struct AvCodecLib
-{
-  const char* Name;
-  already_AddRefed<PlatformDecoderModule> (*Factory)();
-  uint32_t Version;
-};
-
 template <int V> class FFmpegDecoderModule
 {
 public:
   static already_AddRefed<PlatformDecoderModule> Create();
 };
 
-static const AvCodecLib sLibs[] = {
-  { "libavcodec-ffmpeg.so.56", FFmpegDecoderModule<55>::Create, 55 },
-  { "libavcodec.so.56", FFmpegDecoderModule<55>::Create, 55 },
-  { "libavcodec.so.55", FFmpegDecoderModule<55>::Create, 55 },
-  { "libavcodec.so.54", FFmpegDecoderModule<54>::Create, 54 },
-  { "libavcodec.so.53", FFmpegDecoderModule<53>::Create, 53 },
-  { "libavcodec.56.dylib", FFmpegDecoderModule<55>::Create, 55 },
-  { "libavcodec.55.dylib", FFmpegDecoderModule<55>::Create, 55 },
-  { "libavcodec.54.dylib", FFmpegDecoderModule<54>::Create, 54 },
-  { "libavcodec.53.dylib", FFmpegDecoderModule<53>::Create, 53 },
+static const char* sLibs[] = {
+#if defined(XP_DARWIN)
+  "libavcodec.56.dylib",
+  "libavcodec.55.dylib",
+  "libavcodec.54.dylib",
+  "libavcodec.53.dylib",
+#else
+  "libavcodec-ffmpeg.so.56",
+  "libavcodec.so.56",
+  "libavcodec.so.55",
+  "libavcodec.so.54",
+  "libavcodec.so.53",
+#endif
 };
 
-void* FFmpegRuntimeLinker::sLinkedLib = nullptr;
-const AvCodecLib* FFmpegRuntimeLinker::sLib = nullptr;
+PRLibrary* FFmpegRuntimeLinker::sLinkedLib = nullptr;
+const char* FFmpegRuntimeLinker::sLib = nullptr;
+static unsigned (*avcodec_version)() = nullptr;
 
 #define AV_FUNC(func, ver) void (*func)();
+
 #define LIBAVCODEC_ALLVERSION
 #include "FFmpegFunctionList.h"
 #undef LIBAVCODEC_ALLVERSION
@@ -63,10 +58,13 @@ FFmpegRuntimeLinker::Link()
   MOZ_ASSERT(NS_IsMainThread());
 
   for (size_t i = 0; i < ArrayLength(sLibs); i++) {
-    const AvCodecLib* lib = &sLibs[i];
-    sLinkedLib = dlopen(lib->Name, RTLD_NOW | RTLD_LOCAL);
+    const char* lib = sLibs[i];
+    PRLibSpec lspec;
+    lspec.type = PR_LibSpec_Pathname;
+    lspec.value.pathname = lib;
+    sLinkedLib = PR_LoadLibraryWithFlags(lspec, PR_LD_NOW | PR_LD_LOCAL);
     if (sLinkedLib) {
-      if (Bind(lib->Name, lib->Version)) {
+      if (Bind(lib)) {
         sLib = lib;
         sLinkStatus = LinkStatus_SUCCEEDED;
         return true;
@@ -78,7 +76,7 @@ FFmpegRuntimeLinker::Link()
 
   FFMPEG_LOG("H264/AAC codecs unsupported without [");
   for (size_t i = 0; i < ArrayLength(sLibs); i++) {
-    FFMPEG_LOG("%s %s", i ? "," : "", sLibs[i].Name);
+    FFMPEG_LOG("%s %s", i ? "," : "", sLibs[i]);
   }
   FFMPEG_LOG(" ]\n");
 
@@ -89,12 +87,23 @@ FFmpegRuntimeLinker::Link()
 }
 
 /* static */ bool
-FFmpegRuntimeLinker::Bind(const char* aLibName, uint32_t Version)
+FFmpegRuntimeLinker::Bind(const char* aLibName)
 {
+  avcodec_version = (typeof(avcodec_version))PR_FindSymbol(sLinkedLib,
+                                                           "avcodec_version");
+  uint32_t major, minor;
+  if (!GetVersion(major, minor)) {
+    return false;
+  }
+  if (major > 55) {
+    // All major greater than 56 currently use the same ABI as 55.
+    major = 55;
+  }
+
 #define LIBAVCODEC_ALLVERSION
 #define AV_FUNC(func, ver)                                                     \
-  if (ver == 0 || ver == Version) {                                            \
-    if (!(func = (typeof(func))dlsym(sLinkedLib, #func))) {                    \
+  if (ver == 0 || ver == major) {                                              \
+    if (!(func = (typeof(func))PR_FindSymbol(sLinkedLib, #func))) {            \
       FFMPEG_LOG("Couldn't load function " #func " from %s.", aLibName);       \
       return false;                                                            \
     }                                                                          \
@@ -111,7 +120,17 @@ FFmpegRuntimeLinker::CreateDecoderModule()
   if (!Link()) {
     return nullptr;
   }
-  RefPtr<PlatformDecoderModule> module = sLib->Factory();
+  uint32_t major, minor;
+  if (!GetVersion(major, minor)) {
+    return  nullptr;
+  }
+
+  RefPtr<PlatformDecoderModule> module;
+  switch (major) {
+    case 53: module = FFmpegDecoderModule<53>::Create(); break;
+    case 54: module = FFmpegDecoderModule<54>::Create(); break;
+    default: module = FFmpegDecoderModule<55>::Create(); break;
+  }
   return module.forget();
 }
 
@@ -119,11 +138,24 @@ FFmpegRuntimeLinker::CreateDecoderModule()
 FFmpegRuntimeLinker::Unlink()
 {
   if (sLinkedLib) {
-    dlclose(sLinkedLib);
+    PR_UnloadLibrary(sLinkedLib);
     sLinkedLib = nullptr;
     sLib = nullptr;
     sLinkStatus = LinkStatus_INIT;
+    avcodec_version = nullptr;
   }
 }
 
+/* static */ bool
+FFmpegRuntimeLinker::GetVersion(uint32_t& aMajor, uint32_t& aMinor)
+{
+  if (!avcodec_version) {
+    return false;
+  }
+  uint32_t version = avcodec_version();
+  aMajor = (version >> 16) & 0xff;
+  aMinor = (version >> 8) & 0xff;
+  return true;
+}
+
 } // namespace mozilla

dom/media/platforms/ffmpeg/FFmpegRuntimeLinker.h

@@ -10,23 +10,24 @@
 #include "PlatformDecoderModule.h"
 #include <stdint.h>
 
+struct PRLibrary;
+
 namespace mozilla
 {
 
-struct AvCodecLib;
-
 class FFmpegRuntimeLinker
 {
 public:
   static bool Link();
   static void Unlink();
   static already_AddRefed<PlatformDecoderModule> CreateDecoderModule();
+  static bool GetVersion(uint32_t& aMajor, uint32_t& aMinor);
 
 private:
-  static void* sLinkedLib;
-  static const AvCodecLib* sLib;
+  static PRLibrary* sLinkedLib;
+  static const char* sLib;
 
-  static bool Bind(const char* aLibName, uint32_t Version);
+  static bool Bind(const char* aLibName);
 
   static enum LinkStatus {
     LinkStatus_INIT = 0,