EME on Android: Improve accuracy of Key System availability.

media/base/android/media_drm_bridge.cc

 // Copyright (c) 2013 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 "media/base/android/media_drm_bridge.h"
 
 #include <stddef.h>
 #include <algorithm>
 #include <utility>
 
 #include "base/android/build_info.h"
 #include "base/android/jni_array.h"
 #include "base/android/jni_string.h"
 #include "base/bind.h"
 #include "base/callback_helpers.h"
 #include "base/containers/hash_tables.h"
 #include "base/lazy_instance.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "base/sys_byteorder.h"
 #include "base/sys_info.h"
 #include "base/thread_task_runner_handle.h"
 #include "jni/MediaDrmBridge_jni.h"
 #include "media/base/android/media_client_android.h"
+#include "media/base/android/media_codec_util.h"
 #include "media/base/android/media_drm_bridge_delegate.h"
 #include "media/base/android/provision_fetcher.h"
 #include "media/base/cdm_key_information.h"
 #include "widevine_cdm_version.h"  // In SHARED_INTERMEDIATE_DIR.
 
 using base::android::AttachCurrentThread;
 using base::android::ConvertUTF8ToJavaString;
 using base::android::ConvertJavaStringToUTF8;
 using base::android::JavaByteArrayToByteVector;
 using base::android::ScopedJavaGlobalRef;
@@ skipping 128 matching lines @@
 base::LazyInstance<KeySystemManager>::Leaky g_key_system_manager =
     LAZY_INSTANCE_INITIALIZER;
 
 // Checks whether |key_system| is supported with |container_mime_type|. Only
 // checks |key_system| support if |container_mime_type| is empty.
 // TODO(xhwang): The |container_mime_type| is not the same as contentType in
 // the EME spec. Revisit this once the spec issue with initData type is
 // resolved.
 bool IsKeySystemSupportedWithTypeImpl(const std::string& key_system,
                                       const std::string& container_mime_type) {
-  if (!MediaDrmBridge::IsAvailable())
+  DCHECK(MediaDrmBridge::IsAvailable());
+
+  if (key_system.empty()) {
+    NOTREACHED();
     return false;
+  }
 
   UUID scheme_uuid = g_key_system_manager.Get().GetUUID(key_system);
   if (scheme_uuid.empty())
     return false;
 
   JNIEnv* env = AttachCurrentThread();
   ScopedJavaLocalRef<jbyteArray> j_scheme_uuid =
       base::android::ToJavaByteArray(env, &scheme_uuid[0], scheme_uuid.size());
   ScopedJavaLocalRef<jstring> j_container_mime_type =
       ConvertUTF8ToJavaString(env, container_mime_type);
@@ skipping 19 matching lines @@
     case MediaDrmBridge::SECURITY_LEVEL_DEFAULT:
       return "";
     case MediaDrmBridge::SECURITY_LEVEL_1:
       return "L1";
     case MediaDrmBridge::SECURITY_LEVEL_3:
       return "L3";
   }
   return "";
 }
 
-}  // namespace
-
-// static
-bool MediaDrmBridge::IsAvailable() {
+bool AreMediaDrmApisAvailable() {
   if (base::android::BuildInfo::GetInstance()->sdk_int() < 19)
     return false;
 
   int32_t os_major_version = 0;
   int32_t os_minor_version = 0;
   int32_t os_bugfix_version = 0;
   base::SysInfo::OperatingSystemVersionNumbers(
       &os_major_version, &os_minor_version, &os_bugfix_version);
   if (os_major_version == 4 && os_minor_version == 4 && os_bugfix_version == 0)
     return false;
 
   return true;
 }
 
+}  // namespace
+
+// MediaDrm is not generally usable without MediaCodec. Thus, both the MediaDrm
+// APIs and MediaCodec APIs must be enabled and not blacklisted.
+// static
+bool MediaDrmBridge::IsAvailable() {
+  if (!AreMediaDrmApisAvailable())
+    return false;
+
+  return MediaCodecUtil::IsMediaCodecAvailable();

[xhwang, 2016/03/02 06:57:08]

nit: how about:

return AreMediaDrmApisAvailable() && MediaCodecUtil::IsMediaCodecAvailable();

[ddorwin, 2016/03/02 21:11:53]

Done.

+}
+
 // static
 bool MediaDrmBridge::RegisterMediaDrmBridge(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
 // static
 bool MediaDrmBridge::IsKeySystemSupported(const std::string& key_system) {
-  DCHECK(!key_system.empty());
+  if (!MediaDrmBridge::IsAvailable())
+    return false;
+
   return IsKeySystemSupportedWithTypeImpl(key_system, "");
 }
 
 // static
 bool MediaDrmBridge::IsKeySystemSupportedWithType(
     const std::string& key_system,
     const std::string& container_mime_type) {
-  DCHECK(!key_system.empty() && !container_mime_type.empty());
+  DCHECK(!container_mime_type.empty()) << "Call IsKeySystemSupported instead";
+
+  if (!MediaDrmBridge::IsAvailable())
+    return false;
+
   return IsKeySystemSupportedWithTypeImpl(key_system, container_mime_type);
 }
 
 // static
 std::vector<std::string> MediaDrmBridge::GetPlatformKeySystemNames() {
+  if (!MediaDrmBridge::IsAvailable())
+    return std::vector<std::string>();
+
   return g_key_system_manager.Get().GetPlatformKeySystemNames();
 }
 
 // static
-scoped_refptr<MediaDrmBridge> MediaDrmBridge::Create(
+scoped_refptr<MediaDrmBridge> MediaDrmBridge::CreateInternal(
     const std::string& key_system,
     SecurityLevel security_level,
     const CreateFetcherCB& create_fetcher_cb,
     const SessionMessageCB& session_message_cb,
     const SessionClosedCB& session_closed_cb,
     const LegacySessionErrorCB& legacy_session_error_cb,
     const SessionKeysChangeCB& session_keys_change_cb,
     const SessionExpirationUpdateCB& session_expiration_update_cb) {
-  DVLOG(1) << __FUNCTION__;
-
-  if (!IsAvailable())
-    return nullptr;
+  // All paths requires the MediaDrmApis.
+  DCHECK(AreMediaDrmApisAvailable());
 
   UUID scheme_uuid = g_key_system_manager.Get().GetUUID(key_system);
   if (scheme_uuid.empty())
     return nullptr;
 
   scoped_refptr<MediaDrmBridge> media_drm_bridge(new MediaDrmBridge(
       scheme_uuid, security_level, create_fetcher_cb, session_message_cb,
       session_closed_cb, legacy_session_error_cb, session_keys_change_cb,
       session_expiration_update_cb));
 
   if (media_drm_bridge->j_media_drm_.is_null())
     media_drm_bridge = nullptr;
 
   return media_drm_bridge;
 }
 
 // static
+scoped_refptr<MediaDrmBridge> MediaDrmBridge::Create(
+    const std::string& key_system,
+    SecurityLevel security_level,
+    const CreateFetcherCB& create_fetcher_cb,
+    const SessionMessageCB& session_message_cb,
+    const SessionClosedCB& session_closed_cb,
+    const LegacySessionErrorCB& legacy_session_error_cb,
+    const SessionKeysChangeCB& session_keys_change_cb,
+    const SessionExpirationUpdateCB& session_expiration_update_cb) {
+  DVLOG(1) << __FUNCTION__;
+
+  if (!IsAvailable())
+    return nullptr;
+
+  return CreateInternal(key_system, security_level, create_fetcher_cb,
+                        session_message_cb, session_closed_cb,
+                        legacy_session_error_cb, session_keys_change_cb,
+                        session_expiration_update_cb);
+}
+
+// static
 scoped_refptr<MediaDrmBridge> MediaDrmBridge::CreateWithoutSessionSupport(
     const std::string& key_system,
     SecurityLevel security_level,
     const CreateFetcherCB& create_fetcher_cb) {
   DVLOG(1) << __FUNCTION__;
 
+  // Sessions won't be used so decoding capability is not required.
+  if (!AreMediaDrmApisAvailable())
+    return nullptr;
+
   return MediaDrmBridge::Create(key_system, security_level, create_fetcher_cb,
                                 SessionMessageCB(), SessionClosedCB(),
                                 LegacySessionErrorCB(), SessionKeysChangeCB(),
                                 SessionExpirationUpdateCB());
 }
 
 void MediaDrmBridge::SetServerCertificate(
     const std::vector<uint8_t>& certificate,
     scoped_ptr<media::SimpleCdmPromise> promise) {
   DVLOG(2) << __FUNCTION__ << "(" << certificate.size() << " bytes)";
@@ skipping 523 matching lines @@
   JNIEnv* env = AttachCurrentThread();
 
   ScopedJavaLocalRef<jbyteArray> j_response = base::android::ToJavaByteArray(
       env, reinterpret_cast<const uint8_t*>(response.data()), response.size());
 
   Java_MediaDrmBridge_processProvisionResponse(env, j_media_drm_.obj(), success,
                                                j_response.obj());
 }
 
 }  // namespace media