bug 1476231 add accessor for ffvpx real DFT functions r=jya

MozReview-Commit-ID: AF2jl6ZnD4z

--HG--
extra : rebase_source : c7f6c60e3f1b282db5aef2f7b84f23b46734513f

dom/media/platforms/ffmpeg/FFmpegRDFTTypes.h

@@ -26,4 +26,11 @@ extern "C" {
 
 }
 
+struct FFmpegRDFTFuncs
+{
+    AvRdftInitFn init;
+    AvRdftCalcFn calc;
+    AvRdftEndFn end;
+};
+
 #endif // FFmpegRDFTTypes_h

dom/media/platforms/ffmpeg/ffvpx/FFVPXRuntimeLinker.cpp

@@ -62,6 +62,7 @@ FFVPXRuntimeLinker::Init()
     return sLinkStatus == LinkStatus_SUCCEEDED;
   }
 
+  MOZ_ASSERT(NS_IsMainThread());
   sLinkStatus = LinkStatus_FAILED;
 
   // We retrieve the path of the lgpllibs library as this is where mozavcodec
@@ -120,4 +121,20 @@ FFVPXRuntimeLinker::CreateDecoderModule()
   return FFmpegDecoderModule<FFVPX_VERSION>::Create(&sFFVPXLib);
 }
 
+/* static */ void
+FFVPXRuntimeLinker::GetRDFTFuncs(FFmpegRDFTFuncs* aOutFuncs)
+{
+  MOZ_ASSERT(sLinkStatus != LinkStatus_INIT);
+  if (sFFVPXLib.av_rdft_init &&
+      sFFVPXLib.av_rdft_calc &&
+      sFFVPXLib.av_rdft_end) {
+    aOutFuncs->init = sFFVPXLib.av_rdft_init;
+    aOutFuncs->calc = sFFVPXLib.av_rdft_calc;
+    aOutFuncs->end = sFFVPXLib.av_rdft_end;
+  } else {
+    NS_WARNING("RDFT functions expected but not found");
+    *aOutFuncs = FFmpegRDFTFuncs(); // zero
+  }
+}
+
 } // namespace mozilla

dom/media/platforms/ffmpeg/ffvpx/FFVPXRuntimeLinker.h

@@ -9,16 +9,24 @@
 
 #include "PlatformDecoderModule.h"
 
+struct FFmpegRDFTFuncs;
+
 namespace mozilla
 {
 
 class FFVPXRuntimeLinker
 {
 public:
+  // Main thread only.
   static bool Init();
+  // Main thread or after Init().
   static already_AddRefed<PlatformDecoderModule> CreateDecoderModule();
 
+  // Call (on any thread) after Init().
+  static void GetRDFTFuncs(FFmpegRDFTFuncs* aOutFuncs);
+
 private:
+  // Set once on the main thread and then read from other threads.
   static enum LinkStatus {
     LinkStatus_INIT = 0,
     LinkStatus_FAILED,

dom/media/platforms/moz.build

@@ -48,6 +48,9 @@ if CONFIG['MOZ_WMF']:
 
 if CONFIG['MOZ_FFVPX'] or CONFIG['MOZ_FFMPEG']:
     # common code to either FFmpeg or FFVPX
+    EXPORTS += [
+        'ffmpeg/FFmpegRDFTTypes.h',
+    ]
     UNIFIED_SOURCES += [
         'ffmpeg/FFmpegLibWrapper.cpp',
     ]