Initial implementation of Encrypted Media Extensions in Chrome.

webkit/media/key_systems.cc

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "webkit/media/key_systems.h"
+
+#include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebString.h"
+
+namespace webkit_media {
+
+namespace {
+
+const char kClearKeyKeySystem[] = "webkit-org.w3.clearkey";
+
+struct MediaFormatAndKeySystem {
+  const char* mime_type;
+  const char* codec;
+  const char* key_system;
+};
+
+static const MediaFormatAndKeySystem
+supported_format_key_system_combinations[] = {
+  // TODO(ddorwin): Reconsider based on how usage of this class evolves.
+  // For now, this class is stateless, so we do not have the opportunity to
+  // build a list using ParseCodecString() like
+  // net::MimeUtil::InitializeMimeTypeMaps(). Therfore, the following line must
+  // be separate entries.
+  // { "video/webm", "vorbis,vp8,vp8.0", kClearKeyKeySystem },
+  { "video/webm", "vorbis", kClearKeyKeySystem },
+  { "video/webm", "vp8", kClearKeyKeySystem },
+  { "video/webm", "vp8.0", kClearKeyKeySystem },
+  { "audio/webm", "vorbis", kClearKeyKeySystem },
+  { "video/webm", "", kClearKeyKeySystem },
+  { "audio/webm", "", kClearKeyKeySystem }
+};
+
+bool IsSupportedKeySystemWithContainerAndCodec(const std::string& mime_type,
+                                               const std::string& codec,
+                                               const std::string& key_system) {
+  for (size_t i = 0;
+       i < arraysize(supported_format_key_system_combinations);
+       ++i) {
+    const MediaFormatAndKeySystem& combination =
+        supported_format_key_system_combinations[i];
+    if (combination.mime_type == mime_type &&
+        combination.codec == codec &&
+        combination.key_system == key_system)
+      return true;
+  }
+
+  return false;
+}
+
+}  // namespace
+
+bool IsSupportedKeySystem(const WebKit::WebString& key_system) {
+  if (key_system == kClearKeyKeySystem)
+    return true;
+  return false;
+}
+
+bool IsSupportedKeySystemWithMediaMimeType(
+    const std::string& mime_type,
+    const std::vector<std::string>& codecs,
+    const std::string& key_system) {
+  if (codecs.empty())
+    return IsSupportedKeySystemWithContainerAndCodec(mime_type, "", key_system);
+
+  for (size_t i = 0; i < codecs.size(); ++i) {
+    if (!IsSupportedKeySystemWithContainerAndCodec(
+            mime_type, codecs[i], key_system))
+      return false;
+  }
+
+  return true;
+}
+
+}  // namespace webkit_media