Add Promises for EME (Chromium side)

content/renderer/media/android/proxy_media_keys.cc

 // 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.
 
 #include "content/renderer/media/android/proxy_media_keys.h"
 
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/logging.h"
 #include "content/renderer/media/android/renderer_media_player_manager.h"
 #include "content/renderer/media/crypto/key_systems.h"
+#include "media/base/cdm_promise.h"
 
 namespace content {
 
 int ProxyMediaKeys::next_cdm_id_ =
     RendererMediaPlayerManager::kInvalidCdmId + 1;
 
 scoped_ptr<ProxyMediaKeys> ProxyMediaKeys::Create(
     const std::string& key_system,
     const GURL& security_origin,
     RendererMediaPlayerManager* manager,
-    const media::SessionCreatedCB& session_created_cb,
     const media::SessionMessageCB& session_message_cb,
     const media::SessionReadyCB& session_ready_cb,
     const media::SessionClosedCB& session_closed_cb,
     const media::SessionErrorCB& session_error_cb) {
   DCHECK(manager);
   scoped_ptr<ProxyMediaKeys> proxy_media_keys(
       new ProxyMediaKeys(manager,
-                         session_created_cb,
                          session_message_cb,
                          session_ready_cb,
                          session_closed_cb,
                          session_error_cb));
   proxy_media_keys->InitializeCdm(key_system, security_origin);
   return proxy_media_keys.Pass();
 }
 
 ProxyMediaKeys::~ProxyMediaKeys() {
   manager_->DestroyCdm(cdm_id_);
+
+  // Reject any outstanding promises.
+  for (SimplePromiseMap::iterator it =
+           session_id_to_simple_promise_map_.begin();
+       it != session_id_to_simple_promise_map_.end();
+       ++it) {
+    it->second->reject(media::MediaKeys::EXCEPTION_ABORT_ERROR,
+                       0,
+                       "The operation was aborted.");
+  }
+  for (NewSessionPromiseMap::iterator it =
+           session_id_to_new_session_promise_map_.begin();
+       it != session_id_to_new_session_promise_map_.end();
+       ++it) {
+    it->second->reject(media::MediaKeys::EXCEPTION_ABORT_ERROR,
+                       0,
+                       "The operation was aborted.");
+  }

[xhwang, 2014/05/23 06:01:23]

You need to delete it->second as well otherwise the memory will leak.

[jrummell, 2014/05/29 00:54:40]

They are now ScopedPtrHashMaps which should clean up properly.

 }
 
-bool ProxyMediaKeys::CreateSession(uint32 session_id,
-                                   const std::string& content_type,
-                                   const uint8* init_data,
-                                   int init_data_length) {
+void ProxyMediaKeys::CreateSession(
+    const std::string& init_data_type,
+    const uint8* init_data,
+    int init_data_length,
+    SessionType session_type,
+    scoped_ptr<media::NewSessionCdmPromise> promise) {
   // TODO(xhwang): Move these checks up to blink and DCHECK here.
   // See http://crbug.com/342510
-  CdmHostMsg_CreateSession_ContentType session_type;
-  if (content_type == "audio/mp4" || content_type == "video/mp4") {
-    session_type = CREATE_SESSION_TYPE_MP4;
-  } else if (content_type == "audio/webm" || content_type == "video/webm") {
-    session_type = CREATE_SESSION_TYPE_WEBM;
+  CdmHostMsg_CreateSession_ContentType create_session_content_type;
+  if (init_data_type == "audio/mp4" || init_data_type == "video/mp4") {
+    create_session_content_type = CREATE_SESSION_TYPE_MP4;
+  } else if (init_data_type == "audio/webm" || init_data_type == "video/webm") {
+    create_session_content_type = CREATE_SESSION_TYPE_WEBM;
   } else {
     DLOG(ERROR) << "Unsupported EME CreateSession content type of "
-                << content_type;
-    return false;
+                << init_data_type;
+    promise->reject(
+        EXCEPTION_NOT_SUPPORTED_ERROR,
+        0,
+        "Unsupported EME CreateSession init data type of " + init_data_type);
+    return;
   }
 
+  uint32 session_id = CreateSessionId();
+  RegisterNewSessionPromise(session_id, promise.Pass());
   manager_->CreateSession(
       cdm_id_,
       session_id,
-      session_type,
+      create_session_content_type,
       std::vector<uint8>(init_data, init_data + init_data_length));
-  return true;
 }
 
-void ProxyMediaKeys::LoadSession(uint32 session_id,
-                                 const std::string& web_session_id) {
+void ProxyMediaKeys::LoadSession(
+    const std::string& web_session_id,
+    scoped_ptr<media::NewSessionCdmPromise> promise) {
   // TODO(xhwang): Check key system and platform support for LoadSession in
   // blink and add NOTREACHED() here.
   DLOG(ERROR) << "ProxyMediaKeys doesn't support session loading.";
-  OnSessionError(session_id, media::MediaKeys::kUnknownError, 0);
+  promise->reject(
+      EXCEPTION_NOT_SUPPORTED_ERROR, 0, "LoadSession() is not implemented.");

[xhwang, 2014/05/23 06:01:23]

s/implemented/supported/

[jrummell, 2014/05/29 00:54:40]

Done.

 }
 
-void ProxyMediaKeys::UpdateSession(uint32 session_id,
-                                   const uint8* response,
-                                   int response_length) {
+void ProxyMediaKeys::UpdateSession(
+    const std::string& web_session_id,
+    const uint8* response,
+    int response_length,
+    scoped_ptr<media::SimpleCdmPromise> promise) {
+  uint32 session_id = LookupSessionId(web_session_id);
+  RegisterSimplePromise(session_id, promise.Pass());
   manager_->UpdateSession(
       cdm_id_,
       session_id,
       std::vector<uint8>(response, response + response_length));
 }
 
-void ProxyMediaKeys::ReleaseSession(uint32 session_id) {
+void ProxyMediaKeys::ReleaseSession(
+    const std::string& web_session_id,
+    scoped_ptr<media::SimpleCdmPromise> promise) {
+  uint32 session_id = LookupSessionId(web_session_id);
+  RegisterSimplePromise(session_id, promise.Pass());
   manager_->ReleaseSession(cdm_id_, session_id);
 }
 
 void ProxyMediaKeys::OnSessionCreated(uint32 session_id,
                                       const std::string& web_session_id) {
-  session_created_cb_.Run(session_id, web_session_id);
+  AssignWebSessionId(session_id, web_session_id);
+  scoped_ptr<media::NewSessionCdmPromise> promise =
+      TakeNewSessionPromise(session_id);
+  promise->resolve(web_session_id);
 }
 
 void ProxyMediaKeys::OnSessionMessage(uint32 session_id,
                                       const std::vector<uint8>& message,
                                       const std::string& destination_url) {
-  session_message_cb_.Run(session_id, message, destination_url);
+  session_message_cb_.Run(
+      LookupWebSessionId(session_id), message, destination_url);
 }
 
 void ProxyMediaKeys::OnSessionReady(uint32 session_id) {
-  session_ready_cb_.Run(session_id);
+  std::string web_session_id = LookupWebSessionId(session_id);
+  scoped_ptr<media::SimpleCdmPromise> promise = TakeSimplePromise(session_id);
+  if (promise) {
+    promise->resolve();
+  } else {
+    // Still needed for keyadded.
+    session_ready_cb_.Run(web_session_id);
+  }
 }
 
 void ProxyMediaKeys::OnSessionClosed(uint32 session_id) {
-  session_closed_cb_.Run(session_id);
+  std::string web_session_id = LookupWebSessionId(session_id);
+  DropWebSessionId(web_session_id);
+  scoped_ptr<media::SimpleCdmPromise> promise = TakeSimplePromise(session_id);
+  if (promise) {
+    promise->resolve();
+  } else {
+    // It is possible for the CDM to close a session independent of a
+    // Release() request.
+    session_closed_cb_.Run(web_session_id);

[xhwang, 2014/05/23 06:01:23]

This will be messy if we call ReleaseSession(), and before the call gets to the
CDM, the CDM fires SessionClosed() by itself. But I think it's fine in practice.

+  }
 }
 
 void ProxyMediaKeys::OnSessionError(uint32 session_id,
                                     media::MediaKeys::KeyError error_code,
                                     uint32 system_code) {
-  session_error_cb_.Run(session_id, error_code, system_code);
+  std::string web_session_id = LookupWebSessionId(session_id);
+  media::MediaKeys::Exception exception_code;
+  switch (error_code) {
+    case media::MediaKeys::kClientError:
+      exception_code = media::MediaKeys::EXCEPTION_CLIENT_ERROR;
+      break;
+    case media::MediaKeys::kOutputError:
+      exception_code = media::MediaKeys::EXCEPTION_OUTPUT_ERROR;
+      break;
+    case media::MediaKeys::kUnknownError:
+    default:
+      exception_code = media::MediaKeys::EXCEPTION_UNKNOWN_ERROR;
+      break;
+  }
+
+  scoped_ptr<media::NewSessionCdmPromise> promise =
+      TakeNewSessionPromise(session_id);
+  if (promise) {
+    promise->reject(exception_code, system_code, std::string());
+  } else {
+    // Maybe an error for other set of promises.
+    scoped_ptr<media::SimpleCdmPromise> promise2 =
+        TakeSimplePromise(session_id);
+    if (promise2) {
+      promise2->reject(exception_code, system_code, std::string());
+    } else {
+      // Errors generally happen in response to a request, but it is possible
+      // for something bad to happen in the CDM and it needs to tell the client.
+      session_error_cb_.Run(
+          web_session_id, exception_code, system_code, std::string());
+    }
+  }

[xhwang, 2014/05/23 06:01:23]

The nested if/else is hard to read, how about:

 181   scoped_ptr<media::NewSessionCdmPromise> promise =
 182       TakeNewSessionPromise(session_id);
 183   if (promise) {
 184     promise->reject(exception_code, system_code, std::string());
         return;
 185   }

       // Maybe an error for other set of promises.
 187   scoped_ptr<media::SimpleCdmPromise> promise2 =
 188       TakeSimplePromise(session_id);
 189   if (promise2) 
 190     promise2->reject(exception_code, system_code, std::string());
         return;
 191   }

 192   // Errors generally happen in response to a request, but it is possible
 193   // for something bad to happen in the CDM and it needs to tell the
client.
 194   session_error_cb_.Run(
 195       web_session_id, exception_code, system_code, std::string());

Also, s/promise/new_session_promise/ and s/promise2/simple_promise/.

[jrummell, 2014/05/29 00:54:40]

Done.

 }
 
 int ProxyMediaKeys::GetCdmId() const {
   return cdm_id_;
 }
 
 ProxyMediaKeys::ProxyMediaKeys(
     RendererMediaPlayerManager* manager,
-    const media::SessionCreatedCB& session_created_cb,
     const media::SessionMessageCB& session_message_cb,
     const media::SessionReadyCB& session_ready_cb,
     const media::SessionClosedCB& session_closed_cb,
     const media::SessionErrorCB& session_error_cb)
     : manager_(manager),
       cdm_id_(next_cdm_id_++),
-      session_created_cb_(session_created_cb),
       session_message_cb_(session_message_cb),
       session_ready_cb_(session_ready_cb),
       session_closed_cb_(session_closed_cb),
-      session_error_cb_(session_error_cb) {
+      session_error_cb_(session_error_cb),
+      next_session_id_(1) {
 }
 
 void ProxyMediaKeys::InitializeCdm(const std::string& key_system,
                                    const GURL& security_origin) {
   manager_->InitializeCdm(cdm_id_, this, key_system, security_origin);
 }
 
+uint32_t ProxyMediaKeys::CreateSessionId() {
+  return next_session_id_++;
+}
+
+void ProxyMediaKeys::AssignWebSessionId(uint32_t session_id,
+                                        const std::string& web_session_id) {
+  web_session_to_session_id_map_.insert(
+      std::make_pair(web_session_id, session_id));

[xhwang, 2014/05/23 06:01:23]

DCHECK that web_session_id isn't already in the map? What if the app call
UpdateSession() twice before the CDM resolve the first promise?

[jrummell, 2014/05/29 00:54:40]

Done. AssignWebSession() is called when the CDM resolves the createSession
promise. It would cause problems if the CDM creates multiple sessions with the
same web_session_id.

+}
+
+uint32_t ProxyMediaKeys::LookupSessionId(const std::string& web_session_id) {
+  return web_session_to_session_id_map_.find(web_session_id)->second;
+}
+
+std::string ProxyMediaKeys::LookupWebSessionId(uint32_t session_id) {
+  for (SessionIdMap::iterator it = web_session_to_session_id_map_.begin();
+       it != web_session_to_session_id_map_.end();
+       ++it) {
+    if (it->second == session_id)
+      return it->first;
+  }
+  // Possible to get an error creating a session, so no |web_session_id|
+  // available.
+  return std::string();
+}
+
+void ProxyMediaKeys::DropWebSessionId(std::string web_session_id) {
+  web_session_to_session_id_map_.erase(web_session_id);
+}
+
+void ProxyMediaKeys::RegisterSimplePromise(
+    uint32_t session_id,
+    scoped_ptr<media::SimpleCdmPromise> promise) {
+  // Should only be one promise outstanding for any |session_id|.

[xhwang, 2014/05/23 06:01:23]

ditto, what if the app calls update() twice in a row?

[jrummell, 2014/05/29 00:54:40]

Bad things. Ideally the promise would get passed farther down the stack,
avoiding this problem. Another CL.

+  DCHECK(session_id_to_simple_promise_map_.find(session_id) ==
+         session_id_to_simple_promise_map_.end());
+  session_id_to_simple_promise_map_.insert(
+      std::make_pair(session_id, promise.release()));
+}
+
+scoped_ptr<media::SimpleCdmPromise> ProxyMediaKeys::TakeSimplePromise(
+    uint32_t session_id) {
+  SimplePromiseMap::iterator it =
+      session_id_to_simple_promise_map_.find(session_id);
+  // May not be a promise associated with this session for asynchronous events.
+  if (it == session_id_to_simple_promise_map_.end())
+    return scoped_ptr<media::SimpleCdmPromise>();
+  scoped_ptr<media::SimpleCdmPromise> result(it->second);
+  session_id_to_simple_promise_map_.erase(it);
+  return result.Pass();
+}
+
+void ProxyMediaKeys::RegisterNewSessionPromise(
+    uint32_t session_id,
+    scoped_ptr<media::NewSessionCdmPromise> promise) {
+  // Should only be one promise outstanding for any |session_id|.
+  DCHECK(session_id_to_new_session_promise_map_.find(session_id) ==
+         session_id_to_new_session_promise_map_.end());
+  session_id_to_new_session_promise_map_.insert(
+      std::make_pair(session_id, promise.release()));
+}
+
+scoped_ptr<media::NewSessionCdmPromise> ProxyMediaKeys::TakeNewSessionPromise(

[xhwang, 2014/05/23 06:01:23]

You could have 

template <typename CdmPromiseType> scoped_ptr<CdmPromiseType>
TakeCdmPromise(uint32_t session_id);

So that you don't need to define this function twice.

Hmm, to do that you need a helper function

template <typename CdmPromiseType> ... GetCdmPromiseMap();

I am not sure whether that'll lead to simpler code. Just an idea :)

[jrummell, 2014/05/29 00:54:40]

Noe that there is a CdmPromise base class this gets simpler.

+    uint32_t session_id) {
+  NewSessionPromiseMap::iterator it =
+      session_id_to_new_session_promise_map_.find(session_id);
+  // May not be a promise associated with this session for asynchronous events.
+  if (it == session_id_to_new_session_promise_map_.end())
+    return scoped_ptr<media::NewSessionCdmPromise>();
+  scoped_ptr<media::NewSessionCdmPromise> result(it->second);
+  session_id_to_new_session_promise_map_.erase(it);
+  return result.Pass();
+}
+
 }  // namespace content