Add Promises for EME (Chromium side)

content/renderer/media/android/proxy_media_keys.cc

Index: content/renderer/media/android/proxy_media_keys.cc
diff --git a/content/renderer/media/android/proxy_media_keys.cc b/content/renderer/media/android/proxy_media_keys.cc
index 68175c8e46630e44d49230268de548afe30dc481..df74a1d2a40456862f74f1916b8d8abd64f0bdc0 100644
--- a/content/renderer/media/android/proxy_media_keys.cc
+++ b/content/renderer/media/android/proxy_media_keys.cc
@@ -20,7 +20,6 @@ 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,
@@ -28,7 +27,6 @@ scoped_ptr<ProxyMediaKeys> ProxyMediaKeys::Create(
   DCHECK(manager);
   scoped_ptr<ProxyMediaKeys> proxy_media_keys(
       new ProxyMediaKeys(manager,
-                         session_created_cb,
                          session_message_cb,
                          session_ready_cb,
                          session_closed_cb,
@@ -41,75 +39,124 @@ ProxyMediaKeys::~ProxyMediaKeys() {
   manager_->DestroyCdm(cdm_id_);

[xhwang, 2014/05/05 20:46:42]

We should check session_id_to_promise_map_, reject and destroy any leftover
promises.

Imagine that we call createSession, but the CDM never resolve/reject the
promise. Then user closes the tab...

[jrummell, 2014/05/08 23:37:45]

Done.

 }
 
-bool ProxyMediaKeys::CreateSession(uint32 session_id,
-                                   const std::string& content_type,
-                                   const uint8* init_data,
-                                   int init_data_length) {
+void ProxyMediaKeys::CreateSession(

[prabhur, 2014/05/05 17:57:29]

Do we need a bool return value as before to indicate failure? 

[jrummell, 2014/05/08 23:37:45]

Nope. The promise will be resolved or rejected, possibly asynchronously.

+    const std::string& init_data_type,
+    const uint8* init_data,
+    int init_data_length,
+    SessionType session_type,
+    scoped_ptr<media::MediaKeysSessionPromise> 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 session_content_type;
+  if (init_data_type == "audio/mp4" || init_data_type == "video/mp4") {

[prabhur, 2014/05/05 17:57:29]

Is the value expected to be always lower case? i.e is "AUDIO/mp4" an invalid
data_type ?

[jrummell, 2014/05/08 23:37:45]

The spec states "Initialization data type strings are always matched
case-sensitively. It is recommended that initialization data type strings are
lower-case ASCII strings." We use lower-case.

+    session_content_type = CREATE_SESSION_TYPE_MP4;

[xhwang, 2014/05/05 20:46:42]

I don't feel "session_content_type" is an improvement from "session_type". Maybe
"create_session_content_type" to be accurate?

[jrummell, 2014/05/08 23:37:45]

Done.

+  } else if (init_data_type == "audio/webm" || init_data_type == "video/webm") {
+    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(
+        "NotSupportedError",
+        0,
+        "Unsupported EME CreateSession content type of " + init_data_type);

[xhwang, 2014/05/05 20:46:42]

s/content/init data/?

[jrummell, 2014/05/08 23:37:45]

Done.

+    promise.reset();

[xhwang, 2014/05/05 20:46:42]

No need to reset because it'll go out of scope?

[jrummell, 2014/05/08 23:37:45]

Done.

+    return;
   }
 
+  uint32 session_id = CreateSessionId();
+  AddPromise(session_id, promise.Pass());
   manager_->CreateSession(
       cdm_id_,
       session_id,
-      session_type,
+      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::MediaKeysSessionPromise> 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("NotSupportedError", 0, "LoadSession() is not implemented.");

[xhwang, 2014/05/05 20:46:42]

Hmm, I feel we are exposing Blink details to chromium by having
"NotSupportedError" here. Maybe we should have some standard error strings in
chromium, e.g. in media_keys.h

+ddorwin for comments.

+  promise.reset();

[xhwang, 2014/05/05 20:46:42]

ditto about reset.

[jrummell, 2014/05/08 23:37:45]

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::MediaKeysSessionPromise> promise) {
+  uint32 session_id = LookupSessionId(web_session_id);
+  AddPromise(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::MediaKeysSessionPromise> promise) {
+  uint32 session_id = LookupSessionId(web_session_id);
+  AddPromise(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::MediaKeysSessionPromise> promise =
+      LookupPromise(session_id);
+  promise->resolve(web_session_id);
+  promise.reset();
 }
 
 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::MediaKeysSessionPromise> promise =
+      LookupPromise(session_id);
+  if (promise) {
+    promise->resolve();
+    promise.reset();
+  } else {
+    session_ready_cb_.Run(web_session_id);

[xhwang, 2014/05/05 20:46:42]

OnSessionReady() should always be the result of an Update() call, so could this
"else" happen? Maybe I am missing something. If so, please add a comment.

[jrummell, 2014/05/08 23:37:45]

Added comment.

+  }
 }
 
 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::MediaKeysSessionPromise> promise =
+      LookupPromise(session_id);
+  if (promise) {
+    promise->resolve();
+    promise.reset();
+  } else {
+    session_closed_cb_.Run(web_session_id);
+  }

[xhwang, 2014/05/05 20:46:42]

We need to comment why the "else" is a legit case (e.g. the session can be
closed by the CDM?

[jrummell, 2014/05/08 23:37:45]

Done.

 }
 
 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);
+  scoped_ptr<media::MediaKeysSessionPromise> promise =
+      LookupPromise(session_id);
+  if (promise) {
+    promise->reject("InvalidStateError", 0, std::string());
+    promise.reset();
+  } else {
+    session_error_cb_.Run(
+        web_session_id, "InvalidStateError", system_code, std::string());
+  }

[xhwang, 2014/05/05 20:46:42]

ditto about adding a comment, that the sessionError can be a result of a CDM
call, or just something bad happens in the CDM.

[jrummell, 2014/05/08 23:37:45]

Done.

 }
 
 int ProxyMediaKeys::GetCdmId() const {
@@ -118,18 +165,17 @@ int ProxyMediaKeys::GetCdmId() const {
 
 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,
@@ -137,4 +183,57 @@ void ProxyMediaKeys::InitializeCdm(const std::string& key_system,
   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));
+}
+
+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) {
+  std::map<std::string, uint32_t>::iterator it;
+  for (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::AddPromise(
+    uint32_t session_id,
+    scoped_ptr<media::MediaKeysSessionPromise> promise) {
+  // Should only be one promise outstanding for any |session_id|.
+  DCHECK(session_id_to_promise_map_.find(session_id) ==
+         session_id_to_promise_map_.end());
+  session_id_to_promise_map_.insert(
+      std::make_pair(session_id, promise.release()));
+}
+
+scoped_ptr<media::MediaKeysSessionPromise> ProxyMediaKeys::LookupPromise(
+    uint32_t session_id) {
+  std::map<uint32_t, media::MediaKeysSessionPromise*>::iterator it =
+      session_id_to_promise_map_.find(session_id);
+  // May not be a promise associated with this session for asynchronous events.
+  if (it == session_id_to_promise_map_.end())
+    return scoped_ptr<media::MediaKeysSessionPromise>();
+  scoped_ptr<media::MediaKeysSessionPromise> result(it->second);
+  session_id_to_promise_map_.erase(it);
+  return result.Pass();
+}
+
 }  // namespace content