Bug 1271491: P6. Remove the need to call PDMFactory::Init(). r=cpearce

PDMFactory will automatically load and initialize the required frameworks upon first use.
Also fix constness of some methods.

MozReview-Commit-ID: HFbvTMRFAey

--HG--
extra : rebase_source : ce3e7ff6cefc35b32674c9a81c3488fe21b48626

dom/media/ADTSDecoder.cpp

@@ -32,7 +32,6 @@ ADTSDecoder::CreateStateMachine()
 /* static */ bool
 ADTSDecoder::IsEnabled()
 {
-  PDMFactory::Init();
   RefPtr<PDMFactory> platform = new PDMFactory();
   return platform->SupportsMimeType(NS_LITERAL_CSTRING("audio/mp4a-latm"),
                                     /* DecoderDoctorDiagnostics* */ nullptr);

dom/media/Benchmark.cpp

@@ -7,6 +7,7 @@
 #include "Benchmark.h"
 #include "BufferMediaResource.h"
 #include "MediaData.h"
+#include "MediaPrefs.h"
 #include "PDMFactory.h"
 #include "WebMDemuxer.h"
 #include "mozilla/Preferences.h"
@@ -45,8 +46,6 @@ VP9Benchmark::IsVP9DecodeFast()
     RefPtr<WebMDemuxer> demuxer =
       new WebMDemuxer(new BufferMediaResource(sWebMSample, sizeof(sWebMSample), nullptr,
                                               NS_LITERAL_CSTRING("video/webm")));
-    PDMFactory::Init();
-
     RefPtr<Benchmark> estimiser =
       new Benchmark(demuxer,
                     {
@@ -135,7 +134,7 @@ Benchmark::Init()
 {
   MOZ_ASSERT(NS_IsMainThread());
 
-  PDMFactory::Init();
+  MediaPrefs::GetSingleton();
 }
 
 BenchmarkPlayback::BenchmarkPlayback(Benchmark* aMainThreadState,

dom/media/MP3Decoder.cpp

@@ -31,7 +31,6 @@ MP3Decoder::CreateStateMachine() {
 /* static */
 bool
 MP3Decoder::IsEnabled() {
-  PDMFactory::Init();
   RefPtr<PDMFactory> platform = new PDMFactory();
   return platform->SupportsMimeType(NS_LITERAL_CSTRING("audio/mpeg"),
                                     /* DecoderDoctorDiagnostics* */ nullptr);

dom/media/MediaFormatReader.cpp

@@ -172,7 +172,6 @@ nsresult
 MediaFormatReader::Init()
 {
   MOZ_ASSERT(NS_IsMainThread(), "Must be on main thread.");
-  PDMFactory::Init();
 
   InitLayersBackendType();
 

dom/media/fmp4/MP4Decoder.cpp

@@ -151,7 +151,6 @@ MP4Decoder::CanHandleMediaType(const nsACString& aMIMETypeExcludingCodecs,
   }
 
   // Verify that we have a PDM that supports the whitelisted types.
-  PDMFactory::Init();
   RefPtr<PDMFactory> platform = new PDMFactory();
   for (const nsCString& codecMime : codecMimes) {
     if (!platform->SupportsMimeType(codecMime, aDiagnostics)) {
@@ -230,8 +229,6 @@ CreateTestH264Decoder(layers::LayersBackend aBackend,
   aConfig.mExtraData->AppendElements(sTestH264ExtraData,
                                      MOZ_ARRAY_LENGTH(sTestH264ExtraData));
 
-  PDMFactory::Init();
-
   RefPtr<PDMFactory> platform = new PDMFactory();
   RefPtr<MediaDataDecoder> decoder(
     platform->CreateDecoder(aConfig, aTaskQueue, nullptr,

dom/media/platforms/PDMFactory.cpp

@@ -26,9 +26,10 @@
 #endif
 #include "GMPDecoderModule.h"
 
-#include "mozilla/TaskQueue.h"
-
+#include "mozilla/ClearOnShutdown.h"
 #include "mozilla/SharedThreadPool.h"
+#include "mozilla/StaticPtr.h"
+#include "mozilla/TaskQueue.h"
 
 #include "MediaInfo.h"
 #include "MediaPrefs.h"
@@ -44,42 +45,38 @@
 
 #include "DecoderDoctorDiagnostics.h"
 
+
 namespace mozilla {
 
 extern already_AddRefed<PlatformDecoderModule> CreateAgnosticDecoderModule();
 extern already_AddRefed<PlatformDecoderModule> CreateBlankDecoderModule();
 
-/* static */
-void
-PDMFactory::Init()
-{
-  MOZ_ASSERT(NS_IsMainThread());
-  static bool alreadyInitialized = false;
-  if (alreadyInitialized) {
-    return;
-  }
-  alreadyInitialized = true;
-
-  // Ensure MediaPrefs are initialized.
-  MediaPrefs::GetSingleton();
-
+class PDMFactoryImpl final {
+public:
+  PDMFactoryImpl()
+  {
 #ifdef XP_WIN
-  WMFDecoderModule::Init();
+    WMFDecoderModule::Init();
 #endif
 #ifdef MOZ_APPLEMEDIA
-  AppleDecoderModule::Init();
+    AppleDecoderModule::Init();
 #endif
 #ifdef MOZ_FFVPX
-  FFVPXRuntimeLinker::Init();
+    FFVPXRuntimeLinker::Init();
 #endif
 #ifdef MOZ_FFMPEG
-  FFmpegRuntimeLinker::Init();
+    FFmpegRuntimeLinker::Init();
 #endif
-  GMPDecoderModule::Init();
-}
+    GMPDecoderModule::Init();
+  }
+};
+
+StaticAutoPtr<PDMFactoryImpl> PDMFactory::sInstance;
+StaticMutex PDMFactory::sMonitor;
 
 PDMFactory::PDMFactory()
 {
+  EnsureInit();
   CreatePDMs();
 }
 
@@ -87,13 +84,29 @@ PDMFactory::~PDMFactory()
 {
 }
 
+void
+PDMFactory::EnsureInit() const
+{
+  StaticMutexAutoLock mon(sMonitor);
+  if (!sInstance) {
+    sInstance = new PDMFactoryImpl();
+    if (NS_IsMainThread()) {
+      ClearOnShutdown(&sInstance);
+    } else {
+      nsCOMPtr<nsIRunnable> runnable =
+        NS_NewRunnableFunction([]() { ClearOnShutdown(&sInstance); });
+      NS_DispatchToMainThread(runnable);
+    }
+  }
+}
+
 already_AddRefed<MediaDataDecoder>
 PDMFactory::CreateDecoder(const TrackInfo& aConfig,
                           FlushableTaskQueue* aTaskQueue,
                           MediaDataDecoderCallback* aCallback,
                           DecoderDoctorDiagnostics* aDiagnostics,
                           layers::LayersBackend aLayersBackend,
-                          layers::ImageContainer* aImageContainer)
+                          layers::ImageContainer* aImageContainer) const
 {
   bool isEncrypted = mEMEPDM && aConfig.mCrypto.mValid;
 
@@ -148,7 +161,7 @@ PDMFactory::CreateDecoderWithPDM(PlatformDecoderModule* aPDM,
                                  MediaDataDecoderCallback* aCallback,
                                  DecoderDoctorDiagnostics* aDiagnostics,
                                  layers::LayersBackend aLayersBackend,
-                                 layers::ImageContainer* aImageContainer)
+                                 layers::ImageContainer* aImageContainer) const
 {
   MOZ_ASSERT(aPDM);
   RefPtr<MediaDataDecoder> m;

dom/media/platforms/PDMFactory.h

@@ -8,12 +8,15 @@
 #define PDMFactory_h_
 
 #include "PlatformDecoderModule.h"
+#include "mozilla/StaticMutex.h"
 
 class CDMProxy;
 
 namespace mozilla {
 
 class DecoderDoctorDiagnostics;
+class PDMFactoryImpl;
+template<class T> class StaticAutoPtr;
 
 class PDMFactory final {
 public:
@@ -21,10 +24,6 @@ public:
 
   PDMFactory();
 
-  // Call on the main thread to initialize the static state
-  // needed by Create().
-  static void Init();
-
   // Factory method that creates the appropriate PlatformDecoderModule for
   // the platform we're running on. Caller is responsible for deleting this
   // instance. It's expected that there will be multiple
@@ -36,7 +35,7 @@ public:
                 MediaDataDecoderCallback* aCallback,
                 DecoderDoctorDiagnostics* aDiagnostics,
                 layers::LayersBackend aLayersBackend = layers::LayersBackend::LAYERS_NONE,
-                layers::ImageContainer* aImageContainer = nullptr);
+                layers::ImageContainer* aImageContainer = nullptr) const;
 
   bool SupportsMimeType(const nsACString& aMimeType,
                         DecoderDoctorDiagnostics* aDiagnostics) const;
@@ -67,7 +66,7 @@ private:
                        MediaDataDecoderCallback* aCallback,
                        DecoderDoctorDiagnostics* aDiagnostics,
                        layers::LayersBackend aLayersBackend,
-                       layers::ImageContainer* aImageContainer);
+                       layers::ImageContainer* aImageContainer) const;
 
   nsTArray<RefPtr<PlatformDecoderModule>> mCurrentPDMs;
   RefPtr<PlatformDecoderModule> mEMEPDM;
@@ -75,6 +74,11 @@ private:
   bool mWMFFailedToLoad = false;
   bool mFFmpegFailedToLoad = false;
   bool mGMPPDMFailedToStartup = false;
+
+  void EnsureInit() const;
+  template<class T> friend class StaticAutoPtr;
+  static StaticAutoPtr<PDMFactoryImpl> sInstance;
+  static StaticMutex sMonitor;
 };
 
 } // namespace mozilla

dom/media/wave/WaveDecoder.cpp

@@ -40,7 +40,6 @@ WaveDecoder::IsEnabled()
   if (!Preferences::GetBool("media.wave.decoder.enabled", false)) {
     return false;
   }
-  PDMFactory::Init();
   RefPtr<PDMFactory> platform = new PDMFactory();
   return platform->SupportsMimeType(NS_LITERAL_CSTRING("audio/x-wav"),
                                     /* DecoderDoctorDiagnostics* */ nullptr);