Fix: Adding list of supported codecs for MP4 containers

net/base/mime_util.cc

Index: net/base/mime_util.cc
diff --git a/net/base/mime_util.cc b/net/base/mime_util.cc
index 442910b94c7abd536d0f92ffc4c86c55990f1128..61fc5c3d5f9200051725ea2c2375bffe1b4ddb5c 100644
--- a/net/base/mime_util.cc
+++ b/net/base/mime_util.cc
@@ -78,7 +78,7 @@ class MimeUtil : public PlatformMimeUtil {
                         bool strip);
 
   bool IsStrictMediaMimeType(const std::string& mime_type) const;
-  bool IsSupportedStrictMediaMimeType(
+  CanPlayType IsSupportedStrictMediaMimeType(
       const std::string& mime_type,
       const std::vector<std::string>& codecs) const;
 
@@ -90,12 +90,19 @@ class MimeUtil : public PlatformMimeUtil {
   typedef base::hash_set<std::string> MimeMappings;
   typedef std::map<std::string, MimeMappings> StrictMappings;
 
+  typedef std::vector<std::string> MimeExpressionMappings;
+  typedef std::map<std::string, MimeExpressionMappings>
+      StrictExpressionMappings;
+
   MimeUtil();
 
   // Returns true if |codecs| is nonempty and all the items in it are present in
   // |supported_codecs|.
   static bool AreSupportedCodecs(const MimeMappings& supported_codecs,
                                  const std::vector<std::string>& codecs);
+  static bool AreSupportedCodecsWithProfile(
+      const MimeExpressionMappings& supported_codecs,
+      const std::vector<std::string>& codecs);
 
   // For faster lookup, keep hash sets.
   void InitializeMimeTypeMaps();
@@ -112,6 +119,7 @@ class MimeUtil : public PlatformMimeUtil {
   MimeMappings codecs_map_;
 
   StrictMappings strict_format_map_;
+  StrictExpressionMappings strict_mp4_format_map_;
 };  // class MimeUtil
 
 // This variable is Leaky because we need to access it from WorkerPool threads.
@@ -460,6 +468,21 @@ static const MediaFormatStrict format_codec_mappings[] = {
   { "audio/x-mp3", "" }
 };
 
+static const char* kProprietaryAudioCodecsExpression =
+    "mp4a,mp4a.40,mp4a.67,mp4a.40.?,mp4a.67.?";

[acolwell GONE FROM CHROMIUM, 2014/05/22 20:21:42]

mp4a is not RFC compliant.

+static const char* kProprietaryCodecsExpression =
+    "avc1,avc3,avc1.??????,avc3.??????,"
+    "mp4a,mp4a.40,mp4a.67,mp4a.40.?,mp4a.67.?";

[acolwell GONE FROM CHROMIUM, 2014/05/22 20:21:42]

mp4a is not RFC compliant.

+
+static const MediaFormatStrict format_mp4_codec_mappings[] = {
+  { "audio/mp4", kProprietaryAudioCodecsExpression },
+  { "audio/x-m4a", kProprietaryAudioCodecsExpression },
+  { "video/mp4", kProprietaryCodecsExpression },
+  { "video/x-m4v", kProprietaryCodecsExpression },
+  { "application/x-mpegurl", kProprietaryCodecsExpression },
+  { "application/vnd.apple.mpegurl", kProprietaryCodecsExpression }
+};
+
 MimeUtil::MimeUtil() {
   InitializeMimeTypeMaps();
 }
@@ -477,6 +500,41 @@ bool MimeUtil::AreSupportedCodecs(const MimeMappings& supported_codecs,
   return !codecs.empty();
 }
 
+bool MimeUtil::AreSupportedCodecsWithProfile(
+    const MimeExpressionMappings& supported_codecs,
+    const std::vector<std::string>& codecs) {
+  DCHECK(!supported_codecs.empty());
+  for (size_t i = 0; i < codecs.size(); ++i) {
+    bool codec_matched = false;
+    for (size_t j = 0; j < supported_codecs.size(); ++j) {
+      if (!MatchPattern(static_cast<base::StringPiece>(codecs[i]),

[acolwell GONE FROM CHROMIUM, 2014/05/22 20:21:42]

nit: static_cast doesn't seem like the right thing here and below. I think you
should probably just use the base::StringPiece constructor. It's even less
characters. :)

+                        static_cast<base::StringPiece>(supported_codecs[j]))) {
+        continue;
+      }
+      if (codecs[i].find('.') != std::string::npos) {

[acolwell GONE FROM CHROMIUM, 2014/05/22 20:21:42]

You seem to be searching for '.' three different ways here. I believe you can
just do the StringSplit here and run the other logic if split_string has a
length > 0. '.' at the end case will result in split_string.back() being an
empty string.

Another alternative would be to just see if the matched pattern has a '?' and
just verify that all string offsets in the pattern that contain a '?' are a
valid hex digit in the codec string. That is actually what you are trying to
verify here anyways and doesn't bake knowledge of the periods into this code.

[amogh.bihani, 2014/05/23 10:57:29]

Wow, the second approach is awesome. :)

+        if (EndsWith(codecs[i], ".", false))
+          return false;
+
+        // Check whether the suffix is hexadecimal.
+        std::vector<std::string> split_string;
+        base::SplitString(codecs[i], '.', &split_string);
+        const std::string& number = split_string.back();
+        for (size_t k = 0; k < number.length(); ++k) {
+          // Don't enforce case sensitivity, even though it's called for, as it
+          // would break some websites.
+          if (!IsHexDigit(number.at(k)))
+            return false;
+        }
+      }
+      codec_matched = true;
+      break;
+    }
+    if (!codec_matched)
+      return false;
+  }
+  return !codecs.empty();
+}
+
 void MimeUtil::InitializeMimeTypeMaps() {
   for (size_t i = 0; i < arraysize(supported_image_types); ++i)
     image_map_.insert(supported_image_types[i]);
@@ -547,6 +605,17 @@ void MimeUtil::InitializeMimeTypeMaps() {
     }
     strict_format_map_[format_codec_mappings[i].mime_type] = codecs;
   }
+  for (size_t i = 0; i < arraysize(format_mp4_codec_mappings); ++i) {
+    std::vector<std::string> mime_type_codecs;
+    ParseCodecString(
+        format_mp4_codec_mappings[i].codecs_list, &mime_type_codecs, false);
+
+    MimeExpressionMappings codecs;
+    for (size_t j = 0; j < mime_type_codecs.size(); ++j) {
+      codecs.push_back(mime_type_codecs[j]);
+    }
+    strict_mp4_format_map_[format_mp4_codec_mappings[i].mime_type] = codecs;
+  }
 }
 
 bool MimeUtil::IsSupportedImageMimeType(const std::string& mime_type) const {
@@ -729,17 +798,33 @@ void MimeUtil::ParseCodecString(const std::string& codecs,
 }
 
 bool MimeUtil::IsStrictMediaMimeType(const std::string& mime_type) const {
-  if (strict_format_map_.find(mime_type) == strict_format_map_.end())
+  if (strict_format_map_.find(mime_type) == strict_format_map_.end() &&
+      strict_mp4_format_map_.find(mime_type) == strict_mp4_format_map_.end())
     return false;
   return true;
 }
 
-bool MimeUtil::IsSupportedStrictMediaMimeType(
+CanPlayType MimeUtil::IsSupportedStrictMediaMimeType(
     const std::string& mime_type,
     const std::vector<std::string>& codecs) const {
-  StrictMappings::const_iterator it = strict_format_map_.find(mime_type);
-  return (it != strict_format_map_.end()) &&
-      AreSupportedCodecs(it->second, codecs);
+  StrictMappings::const_iterator it_strict_map =
+      strict_format_map_.find(mime_type);
+  if ((it_strict_map != strict_format_map_.end()) &&
+      AreSupportedCodecs(it_strict_map->second, codecs)) {
+    return IsSupported;
+  }
+
+  StrictExpressionMappings::const_iterator it_expression_map =
+      strict_mp4_format_map_.find(mime_type);
+  if ((it_expression_map != strict_mp4_format_map_.end()) &&
+      AreSupportedCodecsWithProfile(it_expression_map->second, codecs)) {
+    return MayBeSupported;
+  }
+
+  if (codecs.empty())
+    return MayBeSupported;
+
+  return IsNotSupported;
 }
 
 void MimeUtil::RemoveProprietaryMediaTypesAndCodecsForTests() {
@@ -817,8 +902,9 @@ bool IsStrictMediaMimeType(const std::string& mime_type) {
   return g_mime_util.Get().IsStrictMediaMimeType(mime_type);
 }
 
-bool IsSupportedStrictMediaMimeType(const std::string& mime_type,
-                                    const std::vector<std::string>& codecs) {
+CanPlayType IsSupportedStrictMediaMimeType(
+    const std::string& mime_type,
+    const std::vector<std::string>& codecs) {
   return g_mime_util.Get().IsSupportedStrictMediaMimeType(mime_type, codecs);
 }