Bug 834172 - Implement CreateDecoder in DecoderTraits. r=cpearce

The class DecoderTraits knows about all supported decoders. Adding
an interface to create decoder instances simplifies all users of this
functionality. nsHtmlMediaElement has been updated to use the new
function.

content/html/content/public/nsHTMLMediaElement.h

@@ -379,12 +379,6 @@ protected:
    */
   already_AddRefed<DOMMediaStream> CaptureStreamInternal(bool aFinishWhenEnded);
 
-  /**
-   * Create a decoder for the given aMIMEType. Returns null if we
-   * were unable to create the decoder.
-   */
-  already_AddRefed<MediaDecoder> CreateDecoder(const nsACString& aMIMEType);
-
   /**
    * Initialize a decoder as a clone of an existing decoder in another
    * element.

content/html/content/src/nsHTMLMediaElement.cpp

@@ -75,35 +75,6 @@
 #include "nsIPowerManagerService.h"
 #include <algorithm>
 
-#ifdef MOZ_OGG
-#include "OggDecoder.h"
-#endif
-#ifdef MOZ_WAVE
-#include "WaveDecoder.h"
-#endif
-#ifdef MOZ_WEBM
-#include "WebMDecoder.h"
-#endif
-#ifdef MOZ_RAW
-#include "RawDecoder.h"
-#endif
-#ifdef MOZ_GSTREAMER
-#include "GStreamerDecoder.h"
-#endif
-#ifdef MOZ_MEDIA_PLUGINS
-#include "MediaPluginHost.h"
-#include "MediaPluginDecoder.h"
-#endif
-#ifdef MOZ_WIDGET_GONK
-#include "MediaOmxDecoder.h"
-#endif
-#ifdef MOZ_DASH
-#include "DASHDecoder.h"
-#endif
-#ifdef MOZ_WMF
-#include "WMFDecoder.h"
-#endif
-
 #ifdef PR_LOGGING
 static PRLogModuleInfo* gMediaElementLog;
 static PRLogModuleInfo* gMediaElementEventsLog;
@@ -2194,89 +2165,6 @@ nsHTMLMediaElement::CanPlayType(const nsAString& aType, nsAString& aResult)
   return NS_OK;
 }
 
-already_AddRefed<MediaDecoder>
-nsHTMLMediaElement::CreateDecoder(const nsACString& aType)
-{
-  // If you change this list to add support for new decoders for codecs that
-  // can be used by <audio>, please consider updating MediaDecodeTask::CreateDecoder
-  // as well.
-
-#ifdef MOZ_GSTREAMER
-  if (DecoderTraits::IsGStreamerSupportedType(aType)) {
-    nsRefPtr<GStreamerDecoder> decoder = new GStreamerDecoder();
-    if (decoder->Init(this)) {
-      return decoder.forget();
-    }
-  }
-#endif
-#ifdef MOZ_RAW
-  if (DecoderTraits::IsRawType(aType)) {
-    nsRefPtr<RawDecoder> decoder = new RawDecoder();
-    if (decoder->Init(this)) {
-      return decoder.forget();
-    }
-  }
-#endif
-#ifdef MOZ_OGG
-  if (DecoderTraits::IsOggType(aType)) {
-    nsRefPtr<OggDecoder> decoder = new OggDecoder();
-    if (decoder->Init(this)) {
-      return decoder.forget();
-    }
-  }
-#endif
-#ifdef MOZ_WAVE
-  if (DecoderTraits::IsWaveType(aType)) {
-    nsRefPtr<WaveDecoder> decoder = new WaveDecoder();
-    if (decoder->Init(this)) {
-      return decoder.forget();
-    }
-  }
-#endif
-#ifdef MOZ_WIDGET_GONK
-  if (DecoderTraits::IsOmxSupportedType(aType)) {
-    nsRefPtr<MediaOmxDecoder> decoder = new MediaOmxDecoder();
-    if (decoder->Init(this)) {
-      return decoder.forget();
-    }
-  }
-#endif
-#ifdef MOZ_MEDIA_PLUGINS
-  if (MediaDecoder::IsMediaPluginsEnabled() && GetMediaPluginHost()->FindDecoder(aType, NULL)) {
-    nsRefPtr<MediaPluginDecoder> decoder = new MediaPluginDecoder(aType);
-    if (decoder->Init(this)) {
-      return decoder.forget();
-    }
-  }
-#endif
-#ifdef MOZ_WEBM
-  if (DecoderTraits::IsWebMType(aType)) {
-    nsRefPtr<WebMDecoder> decoder = new WebMDecoder();
-    if (decoder->Init(this)) {
-      return decoder.forget();
-    }
-  }
-#endif
-#ifdef MOZ_DASH
-  if (DecoderTraits::IsDASHMPDType(aType)) {
-    nsRefPtr<DASHDecoder> decoder = new DASHDecoder();
-    if (decoder->Init(this)) {
-      return decoder.forget();
-    }
-  }
-#endif
-#ifdef MOZ_WMF
-  if (DecoderTraits::IsWMFSupportedType(aType)) {
-    nsRefPtr<WMFDecoder> decoder = new WMFDecoder();
-    if (decoder->Init(this)) {
-      return decoder.forget();
-    }
-  }
-#endif
-
-  return nullptr;
-}
-
 nsresult nsHTMLMediaElement::InitializeDecoderAsClone(MediaDecoder* aOriginal)
 {
   NS_ASSERTION(mLoadingSrc, "mLoadingSrc must already be set");
@@ -2323,7 +2211,7 @@ nsresult nsHTMLMediaElement::InitializeDecoderForChannel(nsIChannel *aChannel,
   aChannel->GetContentType(mimeType);
   NS_ASSERTION(!mimeType.IsEmpty(), "We should have the Content-Type.");
 
-  nsRefPtr<MediaDecoder> decoder = CreateDecoder(mimeType);
+  nsRefPtr<MediaDecoder> decoder = DecoderTraits::CreateDecoder(mimeType, this);
   if (!decoder) {
     nsAutoString src;
     GetCurrentSrc(src);

content/media/DecoderTraits.cpp

@@ -17,6 +17,35 @@
 #include "WMFDecoder.h"
 #endif
 
+#ifdef MOZ_OGG
+#include "OggDecoder.h"
+#endif
+#ifdef MOZ_WAVE
+#include "WaveDecoder.h"
+#endif
+#ifdef MOZ_WEBM
+#include "WebMDecoder.h"
+#endif
+#ifdef MOZ_RAW
+#include "RawDecoder.h"
+#endif
+#ifdef MOZ_GSTREAMER
+#include "GStreamerDecoder.h"
+#endif
+#ifdef MOZ_MEDIA_PLUGINS
+#include "MediaPluginHost.h"
+#include "MediaPluginDecoder.h"
+#endif
+#ifdef MOZ_WIDGET_GONK
+#include "MediaOmxDecoder.h"
+#endif
+#ifdef MOZ_DASH
+#include "DASHDecoder.h"
+#endif
+#ifdef MOZ_WMF
+#include "WMFDecoder.h"
+#endif
+
 namespace mozilla
 {
 
@@ -353,5 +382,63 @@ DecoderTraits::CanHandleMediaType(const char* aMIMEType,
   return CANPLAY_YES;
 }
 
+/* static */
+already_AddRefed<MediaDecoder>
+DecoderTraits::CreateDecoder(const nsACString& aType, MediaDecoderOwner* aOwner)
+{
+  nsRefPtr<MediaDecoder> decoder;
+
+#ifdef MOZ_GSTREAMER
+  if (IsGStreamerSupportedType(aType)) {
+    decoder = new GStreamerDecoder();
+  }
+#endif
+#ifdef MOZ_RAW
+  if (IsRawType(aType)) {
+    decoder = new RawDecoder();
+  }
+#endif
+#ifdef MOZ_OGG
+  if (IsOggType(aType)) {
+    decoder = new OggDecoder();
+  }
+#endif
+#ifdef MOZ_WAVE
+  if (IsWaveType(aType)) {
+    decoder = new WaveDecoder();
+  }
+#endif
+#ifdef MOZ_WIDGET_GONK
+  if (IsOmxSupportedType(aType)) {
+    decoder = new MediaOmxDecoder();
+  }
+#endif
+#ifdef MOZ_MEDIA_PLUGINS
+  if (MediaDecoder::IsMediaPluginsEnabled() && GetMediaPluginHost()->FindDecoder(aType, NULL)) {
+    decoder = new MediaPluginDecoder(aType);
+  }
+#endif
+#ifdef MOZ_WEBM
+  if (IsWebMType(aType)) {
+    decoder = new WebMDecoder();
+  }
+#endif
+#ifdef MOZ_DASH
+  if (IsDASHMPDType(aType)) {
+    decoder = new DASHDecoder();
+  }
+#endif
+#ifdef MOZ_WMF
+  if (IsWMFSupportedType(aType)) {
+    decoder = new WMFDecoder();
+  }
+#endif
+
+  NS_ENSURE_TRUE(decoder != nullptr, nullptr);
+  NS_ENSURE_TRUE(decoder->Init(aOwner), nullptr);
+
+  return decoder.forget();
+}
+
 }
 

content/media/DecoderTraits.h

@@ -7,11 +7,15 @@
 #ifndef DecoderTraits_h_
 #define DecoderTraits_h_
 
+#include "nsCOMPtr.h"
 #include "nsAString.h"
 
 namespace mozilla
 {
 
+class MediaDecoder;
+class MediaDecoderOwner;
+
 enum CanPlayStatus {
   CANPLAY_NO,
   CANPLAY_MAYBE,
@@ -74,6 +78,11 @@ public:
 #ifdef MOZ_WMF
   static bool IsWMFSupportedType(const nsACString& aType);
 #endif
+
+  // Create a decoder for the given aType. Returns null if we
+  // were unable to create the decoder.
+  static already_AddRefed<MediaDecoder> CreateDecoder(const nsACString& aType,
+                                                      MediaDecoderOwner* aOwner);
 };
 
 }