Bug 814284 - Part 2: Move the logic of dealing with requested codecs down into DecoderTraits::CanHandleMediaType; r=cpearce

content/html/content/src/nsHTMLMediaElement.cpp

@@ -41,7 +41,6 @@
 #include "nsMediaError.h"
 #include "MediaDecoder.h"
 #include "nsICategoryManager.h"
-#include "nsCharSeparatedTokenizer.h"
 #include "MediaResource.h"
 
 #include "nsIDOMHTMLVideoElement.h"
@@ -2049,16 +2048,6 @@ void nsHTMLMediaElement::UnbindFromTree(bool aDeep,
   nsGenericHTMLElement::UnbindFromTree(aDeep, aNullParent);
 }
 
-static bool
-CodecListContains(char const *const * aCodecs, const nsAString& aCodec)
-{
-  for (int32_t i = 0; aCodecs[i]; ++i) {
-    if (aCodec.EqualsASCII(aCodecs[i]))
-      return true;
-  }
-  return false;
-}
-
 /* static */
 CanPlayStatus
 nsHTMLMediaElement::GetCanPlay(const nsAString& aType)
@@ -2069,39 +2058,13 @@ nsHTMLMediaElement::GetCanPlay(const nsAString& aType)
   if (NS_FAILED(rv))
     return CANPLAY_NO;
 
-  NS_ConvertUTF16toUTF8 mimeTypeUTF8(mimeType);
-  char const *const * supportedCodecs;
-  CanPlayStatus status = DecoderTraits::CanHandleMediaType(mimeTypeUTF8.get(),
-                                                           &supportedCodecs);
-  if (status == CANPLAY_NO)
-    return CANPLAY_NO;
-
   nsAutoString codecs;
   rv = parser.GetParameter("codecs", codecs);
-  if (NS_FAILED(rv)) {
-    // Parameter not found or whatever
-    return status;
-  }
 
-  CanPlayStatus result = CANPLAY_YES;
-  // See http://www.rfc-editor.org/rfc/rfc4281.txt for the description
-  // of the 'codecs' parameter
-  nsCharSeparatedTokenizer tokenizer(codecs, ',');
-  bool expectMoreTokens = false;
-  while (tokenizer.hasMoreTokens()) {
-    const nsSubstring& token = tokenizer.nextToken();
-
-    if (!CodecListContains(supportedCodecs, token)) {
-      // Totally unsupported codec
-      return CANPLAY_NO;
-    }
-    expectMoreTokens = tokenizer.lastTokenEndedWithSeparator();
-  }
-  if (expectMoreTokens) {
-    // Last codec name was empty
-    return CANPLAY_NO;
-  }
-  return result;
+  NS_ConvertUTF16toUTF8 mimeTypeUTF8(mimeType);
+  return DecoderTraits::CanHandleMediaType(mimeTypeUTF8.get(),
+                                           NS_SUCCEEDED(rv),
+                                           codecs);
 }
 
 NS_IMETHODIMP

content/media/DecoderTraits.cpp

@@ -6,6 +6,7 @@
 
 #include "DecoderTraits.h"
 #include "MediaDecoder.h"
+#include "nsCharSeparatedTokenizer.h"
 #ifdef MOZ_MEDIA_PLUGINS
 #include "MediaPluginHost.h"
 #endif
@@ -13,6 +14,16 @@
 namespace mozilla
 {
 
+static bool
+CodecListContains(char const *const * aCodecs, const nsAString& aCodec)
+{
+  for (int32_t i = 0; aCodecs[i]; ++i) {
+    if (aCodec.EqualsASCII(aCodecs[i]))
+      return true;
+  }
+  return false;
+}
+
 #ifdef MOZ_RAW
 static const char gRawTypes[2][16] = {
   "video/x-raw",
@@ -305,57 +316,82 @@ bool DecoderTraits::ShouldHandleMediaType(const char* aMIMEType)
 /* static */
 CanPlayStatus
 DecoderTraits::CanHandleMediaType(const char* aMIMEType,
-                                       char const *const ** aCodecList)
+                                  bool aHaveRequestedCodecs,
+                                  const nsAString& aRequestedCodecs)
 {
+  char const* const* codecList = nullptr;
+  CanPlayStatus result = CANPLAY_NO;
 #ifdef MOZ_RAW
   if (IsRawType(nsDependentCString(aMIMEType))) {
-    *aCodecList = gRawCodecs;
-    return CANPLAY_MAYBE;
+    codecList = gRawCodecs;
+    result = CANPLAY_MAYBE;
   }
 #endif
 #ifdef MOZ_OGG
   if (IsOggType(nsDependentCString(aMIMEType))) {
-    *aCodecList = MediaDecoder::IsOpusEnabled() ? gOggCodecsWithOpus : gOggCodecs;
-    return CANPLAY_MAYBE;
+    codecList = MediaDecoder::IsOpusEnabled() ? gOggCodecsWithOpus : gOggCodecs;
+    result = CANPLAY_MAYBE;
   }
 #endif
 #ifdef MOZ_WAVE
   if (IsWaveType(nsDependentCString(aMIMEType))) {
-    *aCodecList = gWaveCodecs;
-    return CANPLAY_MAYBE;
+    codecList = gWaveCodecs;
+    result = CANPLAY_MAYBE;
   }
 #endif
 #ifdef MOZ_WEBM
   if (IsWebMType(nsDependentCString(aMIMEType))) {
-    *aCodecList = gWebMCodecs;
-    return CANPLAY_YES;
+    codecList = gWebMCodecs;
+    result = CANPLAY_YES;
   }
 #endif
 #ifdef MOZ_DASH
   if (IsDASHMPDType(nsDependentCString(aMIMEType))) {
     // DASH manifest uses WebM codecs only.
-    *aCodecList = gWebMCodecs;
-    return CANPLAY_YES;
+    codecList = gWebMCodecs;
+    result = CANPLAY_YES;
   }
 #endif
 
 #ifdef MOZ_GSTREAMER
   if (IsH264Type(nsDependentCString(aMIMEType))) {
-    *aCodecList = gH264Codecs;
-    return CANPLAY_MAYBE;
+    codecList = gH264Codecs;
+    result = CANPLAY_MAYBE;
   }
 #endif
 #ifdef MOZ_WIDGET_GONK
   if (IsOmxSupportedType(nsDependentCString(aMIMEType))) {
-    *aCodecList = gH264Codecs;
-    return CANPLAY_MAYBE;
+    codecList = gH264Codecs;
+    result = CANPLAY_MAYBE;
   }
 #endif
 #ifdef MOZ_MEDIA_PLUGINS
-  if (MediaDecoder::IsMediaPluginsEnabled() && GetMediaPluginHost()->FindDecoder(nsDependentCString(aMIMEType), aCodecList))
-    return CANPLAY_MAYBE;
+  if (MediaDecoder::IsMediaPluginsEnabled() &&
+      GetMediaPluginHost()->FindDecoder(nsDependentCString(aMIMEType), &codecList))
+    result = CANPLAY_MAYBE;
 #endif
-  return CANPLAY_NO;
+  if (result == CANPLAY_NO || !aHaveRequestedCodecs) {
+    return result;
+  }
+
+  // See http://www.rfc-editor.org/rfc/rfc4281.txt for the description
+  // of the 'codecs' parameter
+  nsCharSeparatedTokenizer tokenizer(aRequestedCodecs, ',');
+  bool expectMoreTokens = false;
+  while (tokenizer.hasMoreTokens()) {
+    const nsSubstring& token = tokenizer.nextToken();
+
+    if (!CodecListContains(codecList, token)) {
+      // Totally unsupported codec
+      return CANPLAY_NO;
+    }
+    expectMoreTokens = tokenizer.lastTokenEndedWithSeparator();
+  }
+  if (expectMoreTokens) {
+    // Last codec name was empty
+    return CANPLAY_NO;
+  }
+  return CANPLAY_YES;
 }
 
 }

content/media/DecoderTraits.h

@@ -22,11 +22,13 @@ class DecoderTraits {
 public:
   // Returns the CanPlayStatus indicating if we can handle this
   // MIME type. The MIME type should not include the codecs parameter.
-  // If it returns anything other than CANPLAY_NO then it also
-  // returns a null-terminated list of supported codecs
-  // in *aSupportedCodecs. This list should not be freed, it is static data.
+  // That parameter should be passed in aCodecs, and will only be
+  // used if whether a given MIME type being handled depends on the
+  // codec that will be used.  If the codecs parameter has not been
+  // specified, pass false in aHaveRequestedCodecs.
   static CanPlayStatus CanHandleMediaType(const char* aMIMEType,
-                                          char const *const ** aSupportedCodecs);
+                                          bool aHaveRequestedCodecs,
+                                          const nsAString& aRequestedCodecs);
 
   // Returns true if we should handle this MIME type when it appears
   // as an <object> or as a toplevel page. If, in practice, our support