Make HTMLMediaElement.setMediaKeys() asynchronous.

Source/modules/encryptedmedia/HTMLMediaElementEncryptedMedia.cpp

 // Copyright 2014 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 "config.h"
 #include "modules/encryptedmedia/HTMLMediaElementEncryptedMedia.h"
 
 #include "bindings/core/v8/ExceptionState.h"
+#include "bindings/core/v8/ScriptPromise.h"
+#include "bindings/core/v8/ScriptPromiseResolver.h"
+#include "bindings/core/v8/ScriptState.h"
+#include "core/dom/DOMException.h"
 #include "core/dom/ExceptionCode.h"
 #include "core/html/HTMLMediaElement.h"
 #include "core/html/MediaKeyError.h"
 #include "core/html/MediaKeyEvent.h"
 #include "modules/encryptedmedia/MediaKeyNeededEvent.h"
 #include "modules/encryptedmedia/MediaKeys.h"
+#include "modules/encryptedmedia/SimpleContentDecryptionModuleResult.h"
+#include "platform/ContentDecryptionModuleResult.h"
 #include "platform/Logging.h"
 #include "platform/RuntimeEnabledFeatures.h"
+#include "wtf/Functional.h"
 #include "wtf/Uint8Array.h"
 
 namespace blink {
 
 static void throwExceptionIfMediaKeyExceptionOccurred(const String& keySystem, const String& sessionId, blink::WebMediaPlayer::MediaKeyException exception, ExceptionState& exceptionState)
 {
     switch (exception) {
     case blink::WebMediaPlayer::MediaKeyExceptionNoError:
         return;
     case blink::WebMediaPlayer::MediaKeyExceptionInvalidPlayerState:
         exceptionState.throwDOMException(InvalidStateError, "The player is in an invalid state.");
         return;
     case blink::WebMediaPlayer::MediaKeyExceptionKeySystemNotSupported:
         exceptionState.throwDOMException(NotSupportedError, "The key system provided ('" + keySystem +"') is not supported.");
         return;
     case blink::WebMediaPlayer::MediaKeyExceptionInvalidAccess:
         exceptionState.throwDOMException(InvalidAccessError, "The session ID provided ('" + sessionId + "') is invalid.");
         return;
     }
 
     ASSERT_NOT_REACHED();
     return;
 }
 
+// This class allows MediaKeys to be set asynchronously.
+class SetMediaKeysHandler : public ScriptPromiseResolver {
+    WTF_MAKE_NONCOPYABLE(SetMediaKeysHandler);
+
+public:
+    static ScriptPromise create(ScriptState*, HTMLMediaElement&, MediaKeys*);
+    virtual ~SetMediaKeysHandler();
+
+    void ClearExistingMediaKeys(Timer<SetMediaKeysHandler>*);
+    void SetNewMediaKeys();
+    void Finish();
+
+    void ClearFailed(ExceptionCode, const String& errorMessage);

[ddorwin, 2014/08/09 00:36:53]

Unless this is a callback (On...), it should be an action. ReportClearFailed?
Ditto below.

[jrummell, 2014/08/11 21:24:48]

Done.

+    void SetFailed(ExceptionCode, const String& errorMessage);
+
+private:
+    SetMediaKeysHandler(ScriptState*, HTMLMediaElement&, MediaKeys*);
+
+    RawPtrWillBeMember<HTMLMediaElement> m_element;
+    Persistent<MediaKeys> m_newMediaKeys;
+    Timer<SetMediaKeysHandler> m_timer;
+};
+
+typedef Function<void()> SuccessCB;
+typedef Function<void(ExceptionCode, const String&)> FailureCB;
+
+// Represents the result used when setContentDecryptionModule() is called.
+// Calls |success| if result is resolved, |failure| is result is rejected.
+class SetContentDecryptionModuleResult FINAL : public ContentDecryptionModuleResult {
+public:
+    SetContentDecryptionModuleResult(SuccessCB success, FailureCB failure)
+        : m_successCallback(success)
+        , m_failureCallback(failure)
+    {
+    }
+
+    // ContentDecryptionModuleResult implementation.
+    virtual void complete() OVERRIDE
+    {
+        m_successCallback();
+    }
+
+    virtual void completeWithSession(blink::WebContentDecryptionModuleResult::SessionStatus status) OVERRIDE
+    {
+        ASSERT_NOT_REACHED();
+        m_failureCallback(InvalidStateError, "Unexpected completion.");
+    }
+
+    virtual void completeWithError(blink::WebContentDecryptionModuleException code, unsigned long systemCode, const blink::WebString& message) OVERRIDE
+    {
+        m_failureCallback(WebCdmExceptionToExceptionCode(code), message);
+    }
+
+private:
+    SuccessCB m_successCallback;
+    FailureCB m_failureCallback;
+};
+
+ScriptPromise SetMediaKeysHandler::create(ScriptState* scriptState, HTMLMediaElement& element, MediaKeys* mediaKeys)
+{
+    RefPtr<SetMediaKeysHandler> handler = adoptRef(new SetMediaKeysHandler(scriptState, element, mediaKeys));
+    handler->suspendIfNeeded();
+    handler->keepAliveWhilePending();
+    return handler->promise();
+}
+
+SetMediaKeysHandler::SetMediaKeysHandler(ScriptState* scriptState, HTMLMediaElement& element, MediaKeys* mediaKeys)
+    : ScriptPromiseResolver(scriptState)
+    , m_element(element)
+    , m_newMediaKeys(mediaKeys)
+    , m_timer(this, &SetMediaKeysHandler::ClearExistingMediaKeys)
+{
+    WTF_LOG(Media, "SetMediaKeysHandler::SetMediaKeysHandler");
+
+    // 3. Run the remaining steps asynchronously.
+    m_timer.startOneShot(0, FROM_HERE);
+}
+
+SetMediaKeysHandler::~SetMediaKeysHandler()
+{
+}
+
+void SetMediaKeysHandler::ClearExistingMediaKeys(Timer<SetMediaKeysHandler>*)

[ddorwin, 2014/08/09 00:36:53]

It's a bit weird that this action is tied to a Timer. I wonder if we should have
a timer handler (DoSetMK, SetMKInternal) that just calls this.

It's one more function, but it might be clearer. Also, line 118 is a bit weird:
"The timer calls ClearExistingMediaKeys - What? Why?"

WDYT?

[jrummell, 2014/08/11 21:24:48]

Done.

+{
+    WTF_LOG(Media, "SetMediaKeysHandler::ClearExistingMediaKeys");
+    HTMLMediaElementEncryptedMedia& thisElement = HTMLMediaElementEncryptedMedia::from(*m_element);
+
+    // 3.1 If mediaKeys is not null, it is already in use by another media
+    //     element, and the user agent is unable to use it with this element,
+    //     reject promise with a new DOMException whose name is
+    //     "QuotaExceededError".
+    // (Currently no restrictions on using the same MediaKeys with multiple

[ddorwin, 2014/08/09 00:36:52]

Chrome doesn't have any such limitations? I think Pepper D&D and Android will.
For now, let's fail (unless I'm missing something).

I guess that would require more changes, though, so FIXME?

[jrummell, 2014/08/11 21:24:48]

Done.

+    //  media elements.)
+    // 3.2 If the mediaKeys attribute is not null, run the following steps:
+    if (thisElement.m_mediaKeys) {
+        // 3.2.1 If the user agent or CDM do not support removing the
+        //       association, return a promise rejected with a new DOMException
+        //       whose name is "NotSupportedError".
+        // 3.2.2 If the association cannot currently be removed (i.e. during
+        //       playback), return a promise rejected with a new DOMException
+        //       whose name is "InvalidStateError".
+        if (m_element->isPlaying()) {

[ddorwin, 2014/08/09 00:36:52]

m_element->webMediaPlayer() == is loaded?
It's at least what we care about, right?
We'd need to update the message below too.

[jrummell, 2014/08/11 21:24:48]

Done.

+            ClearFailed(InvalidStateError, "The existing MediaKeys object cannot be removed while playing.");

[ddorwin, 2014/08/09 00:36:53]

Because this function includes a step that doesn't belong here and it's just 1
line, I think we should call reject directly.

[jrummell, 2014/08/11 21:24:48]

Done.

+            return;
+        }
+
+        // 3.2.3 Stop using the CDM instance represented by the mediaKeys
+        //       attribute to decrypt media data and remove the association
+        //       with the media element.
+        // 3.2.4 If the preceding step failed, ...
+        //       (done in ClearFailed()).
+        if (m_element->webMediaPlayer()) {
+            SuccessCB successCallback = bind(&SetMediaKeysHandler::SetNewMediaKeys, this);
+            FailureCB failureCallback = bind<ExceptionCode, const String&>(&SetMediaKeysHandler::ClearFailed, this);
+            ContentDecryptionModuleResult* result = new SetContentDecryptionModuleResult(successCallback, failureCallback);
+            m_element->webMediaPlayer()->setContentDecryptionModule(nullptr, result->result());
+
+            // Don't do anything more until |result| is resolved (or rejected).
+            return;
+        }
+    }
+
+    // MediaKeys not currently set or no player connected, so continue on.
+    SetNewMediaKeys();
+}
+
+void SetMediaKeysHandler::SetNewMediaKeys()
+{
+    WTF_LOG(Media, "SetMediaKeysHandler::SetNewMediaKeys");
+
+    // 3.3 If mediaKeys is not null, run the following steps:
+    if (m_newMediaKeys) {
+        // 3.3.1 Associate the CDM instance represented by mediaKeys with the
+        //       media element for decrypting media data.
+        // 3.3.2 If the preceding step failed, run the following steps:
+        //       (done in SetFailed()).
+        // 3.3.3 Run the Attempt to Resume Playback If Necessary algorithm on
+        //       the media element. The user agent may choose to skip this
+        //       step if it knows resuming will fail (i.e. mediaKeys has no
+        //       sessions).

[ddorwin, 2014/08/09 00:36:52]

Handled by Chromium?

[jrummell, 2014/08/11 21:24:48]

Done.

+        if (m_element->webMediaPlayer()) {
+            SuccessCB successCallback = bind(&SetMediaKeysHandler::Finish, this);
+            FailureCB failureCallback = bind<ExceptionCode, const String&>(&SetMediaKeysHandler::SetFailed, this);
+            ContentDecryptionModuleResult* result = new SetContentDecryptionModuleResult(successCallback, failureCallback);
+            m_element->webMediaPlayer()->setContentDecryptionModule(m_newMediaKeys->contentDecryptionModule(), result->result());
+
+            // Don't do anything more until |result| is resolved (or rejected).
+            return;
+        }
+    }
+
+    // MediaKeys doesn't need to be set on the player, so continue on.
+    Finish();
+}
+
+void SetMediaKeysHandler::Finish()
+{
+    WTF_LOG(Media, "SetMediaKeysHandler::Finish");
+    HTMLMediaElementEncryptedMedia& thisElement = HTMLMediaElementEncryptedMedia::from(*m_element);
+
+    // 3.4 Set the mediaKeys attribute to mediaKeys.
+    thisElement.m_mediaKeys = m_newMediaKeys;
+
+    // 3.5 Resolve promise with undefined.
+    resolve();
+}
+
+void SetMediaKeysHandler::ClearFailed(ExceptionCode code, const String& errorMessage)
+{
+    WTF_LOG(Media, "SetMediaKeysHandler::ClearFailed");
+
+    // 3.2.4 If the preceding step failed, reject promise with a new
+    //       DOMException whose name is the appropriate error name and
+    //       that has an appropriate message.
+    reject(DOMException::create(code, errorMessage));
+}
+
+void SetMediaKeysHandler::SetFailed(ExceptionCode code, const String& errorMessage)
+{
+    WTF_LOG(Media, "SetMediaKeysHandler::SetFailed");
+    HTMLMediaElementEncryptedMedia& thisElement = HTMLMediaElementEncryptedMedia::from(*m_element);
+
+    // 3.3.2 If the preceding step failed, run the following steps:
+    // 3.3.2.1 Set the mediaKeys attribute to null.
+    thisElement.m_mediaKeys.clear();
+
+    // 3.3.2.2 Reject promise with a new DOMException whose name is the
+    //         appropriate error name and that has an appropriate message.
+    reject(DOMException::create(code, errorMessage));
+}
+
 HTMLMediaElementEncryptedMedia::HTMLMediaElementEncryptedMedia()
     : m_emeMode(EmeModeNotSelected)
 {
 }
 
 DEFINE_EMPTY_DESTRUCTOR_WILL_BE_REMOVED(HTMLMediaElementEncryptedMedia)
 
 const char* HTMLMediaElementEncryptedMedia::supplementName()
 {
     return "HTMLMediaElementEncryptedMedia";
 }
 
 HTMLMediaElementEncryptedMedia& HTMLMediaElementEncryptedMedia::from(HTMLMediaElement& element)
 {
     HTMLMediaElementEncryptedMedia* supplement = static_cast<HTMLMediaElementEncryptedMedia*>(WillBeHeapSupplement<HTMLMediaElement>::from(element, supplementName()));
     if (!supplement) {
         supplement = new HTMLMediaElementEncryptedMedia();
         provideTo(element, supplementName(), adoptPtrWillBeNoop(supplement));
     }
     return *supplement;
 }
 
-bool HTMLMediaElementEncryptedMedia::setEmeMode(EmeMode emeMode, ExceptionState& exceptionState)
+bool HTMLMediaElementEncryptedMedia::setEmeMode(EmeMode emeMode)
 {
-    if (m_emeMode != EmeModeNotSelected && m_emeMode != emeMode) {
-        exceptionState.throwDOMException(InvalidStateError, "Mixed use of EME prefixed and unprefixed API not allowed.");
+    if (m_emeMode != EmeModeNotSelected && m_emeMode != emeMode)
         return false;
-    }
+
     m_emeMode = emeMode;
     return true;
 }
 
 blink::WebContentDecryptionModule* HTMLMediaElementEncryptedMedia::contentDecryptionModule()
 {
     return m_mediaKeys ? m_mediaKeys->contentDecryptionModule() : 0;
 }
 
 MediaKeys* HTMLMediaElementEncryptedMedia::mediaKeys(HTMLMediaElement& element)
 {
     HTMLMediaElementEncryptedMedia& thisElement = HTMLMediaElementEncryptedMedia::from(element);
     return thisElement.m_mediaKeys.get();
 }
 
-void HTMLMediaElementEncryptedMedia::setMediaKeysInternal(HTMLMediaElement& element, MediaKeys* mediaKeys)
+ScriptPromise HTMLMediaElementEncryptedMedia::setMediaKeys(ScriptState* scriptState, HTMLMediaElement& element, MediaKeys* mediaKeys)
 {
-    if (m_mediaKeys == mediaKeys)
-        return;
+    HTMLMediaElementEncryptedMedia& thisElement = HTMLMediaElementEncryptedMedia::from(element);
+    WTF_LOG(Media, "HTMLMediaElementEncryptedMedia::setMediaKeys current(%p), new(%p)", thisElement.m_mediaKeys.get(), mediaKeys);
 
-    ASSERT(m_emeMode == EmeModeUnprefixed);
-    m_mediaKeys = mediaKeys;
+    if (!thisElement.setEmeMode(EmeModeUnprefixed))
+        return ScriptPromise::rejectWithDOMException(scriptState, DOMException::create(InvalidStateError, "Mixed use of EME prefixed and unprefixed API not allowed."));
 
-    // If a player is connected, tell it that the CDM has changed.
-    if (element.webMediaPlayer())
-        element.webMediaPlayer()->setContentDecryptionModule(contentDecryptionModule());
-}
+    // 1. If mediaKeys and the mediaKeys attribute are the same object, return
+    //    a promise resolved with undefined.
+    if (thisElement.m_mediaKeys == mediaKeys)
+        return ScriptPromise::cast(scriptState, V8ValueTraits<V8UndefinedType>::toV8Value(V8UndefinedType(), scriptState->context()->Global(), scriptState->isolate()));
 
-void HTMLMediaElementEncryptedMedia::setMediaKeys(HTMLMediaElement& element, MediaKeys* mediaKeys, ExceptionState& exceptionState)
-{
-    WTF_LOG(Media, "HTMLMediaElementEncryptedMedia::setMediaKeys");
-    HTMLMediaElementEncryptedMedia& thisElement = HTMLMediaElementEncryptedMedia::from(element);
-
-    if (!thisElement.setEmeMode(EmeModeUnprefixed, exceptionState))
-        return;
-
-    thisElement.setMediaKeysInternal(element, mediaKeys);
+    // 2. Let promise be a new promise. Remaining steps done in handler.
+    return SetMediaKeysHandler::create(scriptState, element, mediaKeys);
 }
 
 // Create a MediaKeyNeededEvent for WD EME.
 static PassRefPtrWillBeRawPtr<Event> createNeedKeyEvent(const String& contentType, const unsigned char* initData, unsigned initDataLength)
 {
     MediaKeyNeededEventInit initializer;
     initializer.contentType = contentType;
     initializer.initData = Uint8Array::create(initData, initDataLength);
     initializer.bubbles = false;
     initializer.cancelable = false;
@@ skipping 16 matching lines @@
 
 void HTMLMediaElementEncryptedMedia::webkitGenerateKeyRequest(HTMLMediaElement& element, const String& keySystem, PassRefPtr<Uint8Array> initData, ExceptionState& exceptionState)
 {
     HTMLMediaElementEncryptedMedia::from(element).generateKeyRequest(element.webMediaPlayer(), keySystem, initData, exceptionState);
 }
 
 void HTMLMediaElementEncryptedMedia::generateKeyRequest(blink::WebMediaPlayer* webMediaPlayer, const String& keySystem, PassRefPtr<Uint8Array> initData, ExceptionState& exceptionState)
 {
     WTF_LOG(Media, "HTMLMediaElementEncryptedMedia::webkitGenerateKeyRequest");
 
-    if (!setEmeMode(EmeModePrefixed, exceptionState))
+    if (!setEmeMode(EmeModePrefixed)) {
+        exceptionState.throwDOMException(InvalidStateError, "Mixed use of EME prefixed and unprefixed API not allowed.");
         return;
+    }
 
     if (keySystem.isEmpty()) {
         exceptionState.throwDOMException(SyntaxError, "The key system provided is empty.");
         return;
     }
 
     if (!webMediaPlayer) {
         exceptionState.throwDOMException(InvalidStateError, "No media has been loaded.");
         return;
     }
@@ skipping 16 matching lines @@
 
 void HTMLMediaElementEncryptedMedia::webkitAddKey(HTMLMediaElement& element, const String& keySystem, PassRefPtr<Uint8Array> key, PassRefPtr<Uint8Array> initData, const String& sessionId, ExceptionState& exceptionState)
 {
     HTMLMediaElementEncryptedMedia::from(element).addKey(element.webMediaPlayer(), keySystem, key, initData, sessionId, exceptionState);
 }
 
 void HTMLMediaElementEncryptedMedia::addKey(blink::WebMediaPlayer* webMediaPlayer, const String& keySystem, PassRefPtr<Uint8Array> key, PassRefPtr<Uint8Array> initData, const String& sessionId, ExceptionState& exceptionState)
 {
     WTF_LOG(Media, "HTMLMediaElementEncryptedMedia::webkitAddKey");
 
-    if (!setEmeMode(EmeModePrefixed, exceptionState))
+    if (!setEmeMode(EmeModePrefixed)) {
+        exceptionState.throwDOMException(InvalidStateError, "Mixed use of EME prefixed and unprefixed API not allowed.");
         return;
+    }
 
     if (keySystem.isEmpty()) {
         exceptionState.throwDOMException(SyntaxError, "The key system provided is empty.");
         return;
     }
 
     if (!key) {
         exceptionState.throwDOMException(SyntaxError, "The key provided is invalid.");
         return;
     }
@@ skipping 26 matching lines @@
 
 void HTMLMediaElementEncryptedMedia::webkitCancelKeyRequest(HTMLMediaElement& element, const String& keySystem, const String& sessionId, ExceptionState& exceptionState)
 {
     HTMLMediaElementEncryptedMedia::from(element).cancelKeyRequest(element.webMediaPlayer(), keySystem, sessionId, exceptionState);
 }
 
 void HTMLMediaElementEncryptedMedia::cancelKeyRequest(blink::WebMediaPlayer* webMediaPlayer, const String& keySystem, const String& sessionId, ExceptionState& exceptionState)
 {
     WTF_LOG(Media, "HTMLMediaElementEncryptedMedia::webkitCancelKeyRequest");
 
-    if (!setEmeMode(EmeModePrefixed, exceptionState))
+    if (!setEmeMode(EmeModePrefixed)) {
+        exceptionState.throwDOMException(InvalidStateError, "Mixed use of EME prefixed and unprefixed API not allowed.");
         return;
+    }
 
     if (keySystem.isEmpty()) {
         exceptionState.throwDOMException(SyntaxError, "The key system provided is empty.");
         return;
     }
 
     if (!webMediaPlayer) {
         exceptionState.throwDOMException(InvalidStateError, "No media has been loaded.");
         return;
     }
@@ skipping 94 matching lines @@
 
 void HTMLMediaElementEncryptedMedia::playerDestroyed(HTMLMediaElement& element)
 {
 #if ENABLE(OILPAN)
     // FIXME: Oilpan: remove this once the media player is on the heap. crbug.com/378229
     if (element.isFinalizing())
         return;
 #endif
 
     HTMLMediaElementEncryptedMedia& thisElement = HTMLMediaElementEncryptedMedia::from(element);
-    thisElement.setMediaKeysInternal(element, 0);
+    if (!thisElement.m_mediaKeys)
+        return;
+
+    ASSERT(thisElement.m_emeMode == EmeModeUnprefixed);
+    thisElement.m_mediaKeys.clear();
+
+    // If a player is connected, tell it that the CDM has changed.

[ddorwin, 2014/08/09 00:36:52]

// There is no player to inform.

[jrummell, 2014/08/11 21:24:48]

Removed since this is called right after m_webMediaPlayer.clear(); (and the
procedure name implies that the player has already been destroyed).

+    ASSERT(!element.webMediaPlayer());
 }
 
 blink::WebContentDecryptionModule* HTMLMediaElementEncryptedMedia::contentDecryptionModule(HTMLMediaElement& element)
 {
     HTMLMediaElementEncryptedMedia& thisElement = HTMLMediaElementEncryptedMedia::from(element);
     return thisElement.contentDecryptionModule();
 }
 
 void HTMLMediaElementEncryptedMedia::trace(Visitor* visitor)
 {
     visitor->trace(m_mediaKeys);
     WillBeHeapSupplement<HTMLMediaElement>::trace(visitor);
 }
 
 } // namespace blink