media: CdmFactory creates CDM (MediaKeys) asynchronously.

media/cdm/proxy_decryptor.h

 // Copyright 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.
 
 #ifndef MEDIA_CDM_PROXY_DECRYPTOR_H_
 #define MEDIA_CDM_PROXY_DECRYPTOR_H_
 
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/containers/hash_tables.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
+#include "media/base/cdm_context.h"
 #include "media/base/decryptor.h"
 #include "media/base/eme_constants.h"
 #include "media/base/media_export.h"
 #include "media/base/media_keys.h"
 #include "url/gurl.h"
 
 namespace media {
 
 class CdmFactory;
 class MediaPermission;
 
 // ProxyDecryptor is for EME v0.1b only. It should not be used for the WD API.
 // A decryptor proxy that creates a real decryptor object on demand and
 // forwards decryptor calls to it.
 //
 // TODO(xhwang): Currently we don't support run-time switching among decryptor
 // objects. Fix this when needed.
 // TODO(xhwang): The ProxyDecryptor is not a Decryptor. Find a better name!
 class MEDIA_EXPORT ProxyDecryptor {
  public:
+  // Callback to provide a CdmContext when the CDM creation is finished.
+  // If CDM creation failed, |cdm_context| will be null.
+  typedef base::Callback<void(CdmContext* cdm_context)> CdmContextReadyCB;
+
   // These are similar to the callbacks in media_keys.h, but pass back the
   // session ID rather than the internal session ID.
   typedef base::Callback<void(const std::string& session_id)> KeyAddedCB;
   typedef base::Callback<void(const std::string& session_id,
                               MediaKeys::KeyError error_code,
                               uint32 system_code)> KeyErrorCB;
   typedef base::Callback<void(const std::string& session_id,
                               const std::vector<uint8>& message,
                               const GURL& destination_url)> KeyMessageCB;
 
   ProxyDecryptor(MediaPermission* media_permission,
                  const KeyAddedCB& key_added_cb,
                  const KeyErrorCB& key_error_cb,
                  const KeyMessageCB& key_message_cb);
   virtual ~ProxyDecryptor();
 
-  // Returns the CdmContext associated with this object.
-  CdmContext* GetCdmContext();
+  // Creates the CDM and fires |cdm_created_cb|. This method should only be
+  // called once. If CDM creation failed, all following GenerateKeyRequest,
+  // AddKey and CancelKeyRequest calls will result in a KeyError.
+  void CreateCdm(CdmFactory* cdm_factory,
+                 const std::string& key_system,
+                 const GURL& security_origin,
+                 const CdmContextReadyCB& cdm_context_ready_cb);
 
-  // Only call this once.
-  bool InitializeCDM(CdmFactory* cdm_factory,
-                     const std::string& key_system,
-                     const GURL& security_origin);
-
-  // May only be called after InitializeCDM() succeeds.
-  bool GenerateKeyRequest(EmeInitDataType init_data_type,
+  // May only be called after CreateCDM().
+  void GenerateKeyRequest(EmeInitDataType init_data_type,
                           const uint8* init_data,
                           int init_data_length);
   void AddKey(const uint8* key, int key_length,
               const uint8* init_data, int init_data_length,
               const std::string& session_id);
   void CancelKeyRequest(const std::string& session_id);
 
  private:
-  // Helper function to create MediaKeys to handle the given |key_system|.
-  scoped_ptr<MediaKeys> CreateMediaKeys(
-      CdmFactory* cdm_factory,
-      const std::string& key_system,
-      const GURL& security_origin);
+  // Callback for CreateCdm().
+  void OnCdmCreated(const std::string& key_system,
+                    const GURL& security_origin,
+                    const CdmContextReadyCB& cdm_context_ready_cb,
+                    scoped_ptr<MediaKeys> cdm);
+
+  void GenerateKeyRequestInternal(EmeInitDataType init_data_type,
+                                  const std::vector<uint8>& init_data);
 
   // Callbacks for firing session events.
   void OnSessionMessage(const std::string& session_id,
                         MediaKeys::MessageType message_type,
                         const std::vector<uint8>& message,
                         const GURL& legacy_destination_url);
   void OnSessionKeysChange(const std::string& session_id,
                            bool has_additional_usable_key,
                            CdmKeysInfo keys_info);
   void OnSessionExpirationUpdate(const std::string& session_id,
@@ skipping 15 matching lines @@
   enum SessionCreationType {
     TemporarySession,
     PersistentSession,
     LoadSession
   };
 
   // Called when a session is actually created or loaded.
   void SetSessionId(SessionCreationType session_type,
                     const std::string& session_id);
 
+  struct PendingGenerateKeyRequestData {
+    PendingGenerateKeyRequestData(EmeInitDataType init_data_type,
+                                  const std::vector<uint8>& init_data);
+    ~PendingGenerateKeyRequestData();
+
+    EmeInitDataType init_data_type;

[ddorwin, 2015/04/11 02:41:48]

nit: consts?

[xhwang, 2015/04/13 18:56:10]

Done.

[xhwang, 2015/04/13 20:46:20]

Actually I need this to be non-const here because I need the copy constructor to
push a PendingGenerateKeyRequestData into a vector. Switch to use ScopedVector
to avoid this issue.

+    std::vector<uint8> init_data;
+  };
+
+  bool is_creating_cdm_;
+
   // The real MediaKeys that manages key operations for the ProxyDecryptor.
   scoped_ptr<MediaKeys> media_keys_;
 
   MediaPermission* media_permission_;
 
   // Callbacks for firing key events.
   KeyAddedCB key_added_cb_;
   KeyErrorCB key_error_cb_;
   KeyMessageCB key_message_cb_;
 
   std::string key_system_;
   GURL security_origin_;
 
   // Keep track of both persistent and non-persistent sessions.
   base::hash_map<std::string, bool> active_sessions_;
 
   bool is_clear_key_;
 
+  std::vector<PendingGenerateKeyRequestData> pending_requests_;
+
   // NOTE: Weak pointers must be invalidated before all other member variables.
   base::WeakPtrFactory<ProxyDecryptor> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ProxyDecryptor);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_CDM_PROXY_DECRYPTOR_H_