Add Promises for EME (Chromium side)

media/base/media_keys.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_BASE_MEDIA_KEYS_H_
 #define MEDIA_BASE_MEDIA_KEYS_H_
 
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "base/memory/scoped_ptr.h"
 #include "media/base/media_export.h"
 
 namespace media {
 
 class Decryptor;
 
+template <typename T>
+class CdmPromise;
+
+typedef CdmPromise<std::string> CdmNewSessionPromise;
+typedef CdmPromise<void> CdmChangeSessionPromise;

[ddorwin, 2014/05/13 22:44:02]

As earlier, "ChangeSession" is odd, and maybe not necessary at all.

[jrummell, 2014/05/15 22:38:09]

Now SimpleCdmPromise (and NewSessionCdmPromise).

+
 // Performs media key operations.
 //
 // All key operations are called on the renderer thread. Therefore, these calls
 // should be fast and nonblocking; key events should be fired asynchronously.
 class MEDIA_EXPORT MediaKeys {
  public:
   // Reported to UMA, so never reuse a value!
   // Must be kept in sync with blink::WebMediaPlayerClient::MediaKeyErrorCode
   // (enforced in webmediaplayer_impl.cc).
   enum KeyError {
     kUnknownError = 1,
     kClientError,
     // The commented v0.1b values below have never been used.
     // kServiceError,
     kOutputError = 4,
     // kHardwareChangeError,
     // kDomainError,
     kMaxKeyError  // Must be last and greater than any legit value.
   };
 
+  // Must be kept in sync with cdm::MediaKeyException (enforced in

[ddorwin, 2014/05/13 22:44:02]

This shouldn't be necessary. This must be a superset of those values, but all
values supported here don't necessarily need to be supported there.

Most importantly, if we use a switch statement instead of casting, we'll ensure
we do the right thing if this list or CDM.h is changed.

[jrummell, 2014/05/15 22:38:09]

Updated. Using a switch statement in clear_key_cdm.cc.

+  // clear_key_cdm.cc).
+  enum MediaKeysException {
+    MEDIA_KEYS_EXCEPTION_NO_MODIFICATION_ALLOWED_ERROR = 7,
+    MEDIA_KEYS_EXCEPTION_NOT_FOUND_ERROR = 8,
+    MEDIA_KEYS_EXCEPTION_NOT_SUPPORTED_ERROR = 9,
+    MEDIA_KEYS_EXCEPTION_INVALID_STATE_ERROR = 11,
+    MEDIA_KEYS_EXCEPTION_SYNTAX_ERROR = 12,
+    MEDIA_KEYS_EXCEPTION_INVALID_MODIFICATION_ERROR = 13,
+    MEDIA_KEYS_EXCEPTION_INVALID_ACCESS_ERROR = 15,
+    MEDIA_KEYS_EXCEPTION_SECURITY_ERROR = 18,
+    MEDIA_KEYS_EXCEPTION_ABORT_ERROR = 20,
+    MEDIA_KEYS_EXCEPTION_QUOTA_EXCEEDED_ERROR = 22,
+    MEDIA_KEYS_EXCEPTION_TIMEOUT_ERROR = 23,
+    MEDIA_KEYS_EXCEPTION_UNKNOWN_ERROR = 30,

[ddorwin, 2014/05/13 22:44:02]

We don't actually need fixed integers for these since they aren't used in a
binary-compatible interface.

[jrummell, 2014/05/15 22:38:09]

Done.

+    MEDIA_KEYS_EXCEPTION_DATA_ERROR = 31,
+    MEDIA_KEYS_EXCEPTION_VERSION_ERROR = 32,
+    MEDIA_KEYS_EXCEPTION_NOT_READABLE_ERROR = 33,
+    MEDIA_KEYS_EXCEPTION_OPERATION_ERROR = 34,
+    MEDIA_KEYS_EXCEPTION_CLIENT_ERROR = 100,
+    MEDIA_KEYS_EXCEPTION_OUTPUT_ERROR = 101
+  };
+
+  // Type of license required when creating/loading a session.
+  // Must be kept in sync with the values specified in the spec:

[ddorwin, 2014/05/13 22:44:02]

What do you mean in sync? The integer values shouldn't matter. Of course we need
to support the various enums, but that applies to any spec-related feature.

[jrummell, 2014/05/15 22:38:09]

Changed.

+  // https://dvcs.w3.org/hg/html-media/raw-file/default/encrypted-media/encrypted-media.html#extensions
+  // Must be kept in sync with cdm::SessionType (enforced in clear_key_cdm.cc).

[ddorwin, 2014/05/13 22:44:02]

ditto

[jrummell, 2014/05/15 22:38:09]

Done.

+  enum SessionType {
+    SESSION_TYPE_TEMPORARY = 0,
+    SESSION_TYPE_PERSISTENT = 1
+  };
+
   const static uint32 kInvalidSessionId = 0;
 
   MediaKeys();
   virtual ~MediaKeys();
 
-  // Creates a session with the |content_type| and |init_data| provided.
-  // Returns true if a session is successfully created, false otherwise.
+  // Creates a session with the |init_data_type|, |init_data| and |session_type|
+  // provided.
   // Note: UpdateSession() and ReleaseSession() should only be called after
-  // SessionCreatedCB is fired.
-  // TODO(jrummell): Remove return value when prefixed API is removed.
-  // See http://crbug.com/342510
-  virtual bool CreateSession(uint32 session_id,
-                             const std::string& content_type,
+  // |promise| is resolved.
+  virtual void CreateSession(const std::string& init_data_type,
                              const uint8* init_data,
-                             int init_data_length) = 0;
+                             int init_data_length,
+                             SessionType session_type,
+                             scoped_ptr<CdmNewSessionPromise> promise) = 0;
 
   // Loads a session with the |web_session_id| provided.
   // Note: UpdateSession() and ReleaseSession() should only be called after
-  // SessionCreatedCB is fired.
-  virtual void LoadSession(uint32 session_id,
-                           const std::string& web_session_id) = 0;
+  // |promise| is resolved.
+  virtual void LoadSession(const std::string& web_session_id,
+                           scoped_ptr<CdmNewSessionPromise> promise) = 0;
 
-  // Updates a session specified by |session_id| with |response|.
-  virtual void UpdateSession(uint32 session_id,
+  // Updates a session specified by |web_session_id| with |response|.
+  virtual void UpdateSession(const std::string& web_session_id,
                              const uint8* response,
-                             int response_length) = 0;
+                             int response_length,
+                             scoped_ptr<CdmChangeSessionPromise> promise) = 0;
 
-  // Releases the session specified by |session_id|.
-  virtual void ReleaseSession(uint32 session_id) = 0;
+  // Releases the session specified by |web_session_id|.
+  virtual void ReleaseSession(const std::string& web_session_id,
+                              scoped_ptr<CdmChangeSessionPromise> promise) = 0;
 
   // Gets the Decryptor object associated with the MediaKeys. Returns NULL if
   // no Decryptor object is associated. The returned object is only guaranteed
   // to be valid during the MediaKeys' lifetime.
   virtual Decryptor* GetDecryptor();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(MediaKeys);
 };
 
 // Key event callbacks. See the spec for details:
 // https://dvcs.w3.org/hg/html-media/raw-file/default/encrypted-media/encrypted-media.html#event-summary
-typedef base::Callback<
-    void(uint32 session_id, const std::string& web_session_id)>
-    SessionCreatedCB;
-
-typedef base::Callback<void(uint32 session_id,
+typedef base::Callback<void(const std::string& web_session_id,
                             const std::vector<uint8>& message,
                             const std::string& destination_url)>
     SessionMessageCB;
 
-typedef base::Callback<void(uint32 session_id)> SessionReadyCB;
+typedef base::Callback<void(const std::string& web_session_id)> SessionReadyCB;
 
-typedef base::Callback<void(uint32 session_id)> SessionClosedCB;
+typedef base::Callback<void(const std::string& web_session_id)> SessionClosedCB;
 
-typedef base::Callback<void(uint32 session_id,
-                            media::MediaKeys::KeyError error_code,
-                            uint32 system_code)> SessionErrorCB;
+typedef base::Callback<void(const std::string& web_session_id,
+                            MediaKeys::MediaKeysException exception_code,
+                            uint32 system_code,
+                            const std::string& error_message)> SessionErrorCB;
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_MEDIA_KEYS_H_