Implement MediaKeySession.load()

Source/modules/encryptedmedia/MediaKeySession.cpp

 /*
  * Copyright (C) 2013 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 29 matching lines @@
 #include "platform/ContentDecryptionModuleResult.h"
 #include "platform/ContentType.h"
 #include "platform/Logging.h"
 #include "platform/MIMETypeRegistry.h"
 #include "platform/Timer.h"
 #include "public/platform/WebContentDecryptionModule.h"
 #include "public/platform/WebContentDecryptionModuleException.h"
 #include "public/platform/WebContentDecryptionModuleSession.h"
 #include "public/platform/WebString.h"
 #include "public/platform/WebURL.h"
+#include "wtf/ASCIICType.h"
 #include "wtf/ArrayBuffer.h"
 #include "wtf/ArrayBufferView.h"
 
+namespace {
+
+// TODO Remove once close/remove CL landed.

[sandersd (OOO until July 31), 2014/10/08 18:18:22]

More specifically? (What is that CL doing that relates to this?)

[jrummell, 2014/10/08 21:13:20]

Removed TODO. Will get merge conflicts, this was just to remind me to keep the
other one.

+const char* kPersistent = "persistent";
+
+// Minimum and maximum length for session ids.
+enum {
+    MinSessionIdLength = 1,
+    MaxSessionIdLength = 512
+};
+
+} // namespace
+
 namespace blink {
 
 static bool isKeySystemSupportedWithInitDataType(const String& keySystem, const String& initDataType)
 {
     ASSERT(!keySystem.isEmpty());
 
     // FIXME: initDataType != contentType. Implement this properly.
     // http://crbug.com/385874.
     String contentType = initDataType;
     if (initDataType == "webm") {
         contentType = "video/webm";
     } else if (initDataType == "cenc") {
         contentType = "video/mp4";
     }
 
     ContentType type(contentType);
     return MIMETypeRegistry::isSupportedEncryptedMediaMIMEType(keySystem, type.type(), type.parameter("codecs"));
 }
 
+// Checks that |sessionId| looks correct. Returns true if all tests pass,
+// false otherwise.
+static bool ValidSessionId(const String& sessionId)

[sandersd (OOO until July 31), 2014/10/08 18:18:22]

isValidSessionId

[jrummell, 2014/10/08 21:13:20]

Done.

+{
+    if ((sessionId.length() < MinSessionIdLength) || (sessionId.length() > MaxSessionIdLength))
+        return false;
+
+    if (!sessionId.containsOnlyASCII())
+        return false;
+
+    // Check that the sessionId only contains alphanumeric characters.
+    for (unsigned i = 0; i < sessionId.length(); ++i) {
+        if (!isASCIIAlphanumeric(sessionId[i]))
+            return false;
+    }
+
+    return true;
+}
+
 // A class holding a pending action.
 class MediaKeySession::PendingAction : public GarbageCollectedFinalized<MediaKeySession::PendingAction> {
 public:
     enum Type {
         GenerateRequest,
+        Load,
         Update,
         Release
     };
 
     Type type() const { return m_type; }
 
     const Persistent<ContentDecryptionModuleResult> result() const
     {
         return m_result;
     }
 
     const RefPtr<ArrayBuffer> data() const
     {
         ASSERT(m_type == GenerateRequest || m_type == Update);
         return m_data;
     }
 
     const String& initDataType() const
     {
         ASSERT(m_type == GenerateRequest);
         return m_initDataType;
     }
 
+    const String& sessionId() const
+    {
+        ASSERT(m_type == Load);
+        return m_initDataType;
+    }
+
     static PendingAction* CreatePendingGenerateRequest(ContentDecryptionModuleResult* result, const String& initDataType, PassRefPtr<ArrayBuffer> initData)
     {
         ASSERT(result);
         ASSERT(initData);
         return new PendingAction(GenerateRequest, result, initDataType, initData);
     }
 
+    static PendingAction* CreatePendingLoadRequest(ContentDecryptionModuleResult* result, const String& sessionId)
+    {
+        ASSERT(result);
+        return new PendingAction(Load, result, sessionId, PassRefPtr<ArrayBuffer>());
+    }
+
     static PendingAction* CreatePendingUpdate(ContentDecryptionModuleResult* result, PassRefPtr<ArrayBuffer> data)
     {
         ASSERT(result);
         ASSERT(data);
         return new PendingAction(Update, result, String(), data);
     }
 
     static PendingAction* CreatePendingRelease(ContentDecryptionModuleResult* result)
     {
         ASSERT(result);
@@ skipping 81 matching lines @@
     void completeWithDOMException(ExceptionCode code, const String& errorMessage)
     {
         m_resolver->reject(DOMException::create(code, errorMessage));
         m_resolver.clear();
     }
 
     RefPtr<ScriptPromiseResolver> m_resolver;
     Member<MediaKeySession> m_session;
 };
 
+// This class wraps the promise resolver used when loading a session
+// and is passed to Chromium to fullfill the promise. This implementation of
+// completeWithSession() will resolve the promise with true/false, while
+// completeWithError() will reject the promise with an exception. complete()
+// is not expected to be called, and will reject the promise.
+class LoadSessionResult : public ContentDecryptionModuleResult {
+public:
+    LoadSessionResult(ScriptState* scriptState, MediaKeySession* session)
+        : m_resolver(ScriptPromiseResolver::create(scriptState))
+        , m_session(session)
+    {
+        WTF_LOG(Media, "LoadSessionResult(%p)", this);
+    }
+
+    virtual ~LoadSessionResult()
+    {
+        WTF_LOG(Media, "~LoadSessionResult(%p)", this);
+    }
+
+    // ContentDecryptionModuleResult implementation.
+    virtual void complete() OVERRIDE
+    {
+        ASSERT_NOT_REACHED();
+        completeWithDOMException(InvalidStateError, "Unexpected completion.");
+    }
+
+    virtual void completeWithSession(WebContentDecryptionModuleResult::SessionStatus status) OVERRIDE
+    {
+        bool result;
+        switch (status) {
+        case WebContentDecryptionModuleResult::NewSession:
+            result = true;
+            break;
+
+        case WebContentDecryptionModuleResult::SessionNotFound:
+            result = false;
+            break;
+
+        case WebContentDecryptionModuleResult::SessionAlreadyExists:
+            ASSERT_NOT_REACHED();
+            completeWithDOMException(InvalidStateError, "Unexpected completion.");
+            return;
+        }
+
+        m_session->finishLoadSession();
+        m_resolver->resolve(result);
+        m_resolver.clear();
+    }
+
+    virtual void completeWithError(WebContentDecryptionModuleException exceptionCode, unsigned long systemCode, const WebString& errorMessage) OVERRIDE
+    {
+        completeWithDOMException(WebCdmExceptionToExceptionCode(exceptionCode), errorMessage);
+    }
+
+    // It is only valid to call this before completion.
+    ScriptPromise promise() { return m_resolver->promise(); }
+
+    void trace(Visitor* visitor)
+    {
+        visitor->trace(m_session);
+        ContentDecryptionModuleResult::trace(visitor);
+    }
+
+private:
+    // Reject the promise with a DOMException.
+    void completeWithDOMException(ExceptionCode code, const String& errorMessage)
+    {
+        m_resolver->reject(DOMException::create(code, errorMessage));
+        m_resolver.clear();
+    }
+
+    RefPtr<ScriptPromiseResolver> m_resolver;
+    Member<MediaKeySession> m_session;
+};
+
 MediaKeySession* MediaKeySession::create(ScriptState* scriptState, MediaKeys* mediaKeys, const String& sessionType)
 {
     RefPtrWillBeRawPtr<MediaKeySession> session = adoptRefCountedGarbageCollectedWillBeNoop(new MediaKeySession(scriptState, mediaKeys, sessionType));
     session->suspendIfNeeded();
     return session.get();
 }
 
 MediaKeySession::MediaKeySession(ScriptState* scriptState, MediaKeys* mediaKeys, const String& sessionType)
     : ActiveDOMObject(scriptState->executionContext())
     , m_keySystem(mediaKeys->keySystem())
@@ skipping 131 matching lines @@
     // 10. Run the following steps asynchronously (documented in
     //     actionTimerFired())
     m_pendingActions.append(PendingAction::CreatePendingGenerateRequest(result, initDataType, initData));
     ASSERT(!m_actionTimer.isActive());
     m_actionTimer.startOneShot(0, FROM_HERE);
 
     // 11. Return promise.
     return promise;
 }
 
+ScriptPromise MediaKeySession::load(ScriptState* scriptState, const String& sessionId)
+{
+    WTF_LOG(Media, "MediaKeySession(%p)::load %s", this, sessionId.ascii().data());
+
+    // From https://dvcs.w3.org/hg/html-media/raw-file/default/encrypted-media/encrypted-media.html#dom-load:
+    // The load(sessionId) method loads the data stored for the sessionId into
+    // the session represented by the object. It must run the following steps:
+
+    // 1. If this object's uninitialized value is false, return a promise
+    //    rejected with a new DOMException whose name is "InvalidStateError".
+    if (!m_isUninitialized) {
+        return ScriptPromise::rejectWithDOMException(
+            scriptState, DOMException::create(InvalidStateError, "The session is already initialized."));
+    }
+
+    // 2. Let this object's uninitialized be false.
+    m_isUninitialized = false;
+
+    // 3. If sessionId is an empty string, return a promise rejected with a
+    //    new DOMException whose name is "InvalidAccessError".
+    if (sessionId.isEmpty()) {
+        return ScriptPromise::rejectWithDOMException(
+            scriptState, DOMException::create(InvalidAccessError, "The sessionId parameter is empty."));
+    }
+
+    // 4. If this object's session type is not "persistent", return a promise
+    //    rejected with a new DOMException whose name is "InvalidAccessError".
+    if (m_sessionType != kPersistent) {
+        return ScriptPromise::rejectWithDOMException(
+            scriptState, DOMException::create(InvalidAccessError, "The session type is not \"persistent\"."));
+    }
+
+    // 5. Let media keys be the MediaKeys object that created this object.
+    //    (Done in constructor.)
+    ASSERT(m_mediaKeys);
+
+    // 6. If the content decryption module corresponding to media keys's
+    //    keySystem attribute does not support loading previous sessions,
+    //    return a promise rejected with a new DOMException whose name is
+    //    "NotSupportedError".
+    //    (Done by CDM.)
+
+    // 7. Let promise be a new promise.
+    LoadSessionResult* result = new LoadSessionResult(scriptState, this);
+    ScriptPromise promise = result->promise();
+
+    // 8. Run the following steps asynchronously (documented in
+    //    actionTimerFired())
+    m_pendingActions.append(PendingAction::CreatePendingLoadRequest(result, sessionId));
+    ASSERT(!m_actionTimer.isActive());
+    m_actionTimer.startOneShot(0, FROM_HERE);
+
+    // 9. Return promise.
+    return promise;
+}
+
 ScriptPromise MediaKeySession::update(ScriptState* scriptState, ArrayBuffer* response)
 {
     RefPtr<ArrayBuffer> responseCopy = ArrayBuffer::create(response->data(), response->byteLength());
     return updateInternal(scriptState, responseCopy.release());
 }
 
 ScriptPromise MediaKeySession::update(ScriptState* scriptState, ArrayBufferView* response)
 {
     RefPtr<ArrayBuffer> responseCopy = ArrayBuffer::create(response->baseAddress(), response->byteLength());
     return updateInternal(scriptState, responseCopy.release());
@@ skipping 95 matching lines @@
             //        "NotSupportedError".
             // 10.3.3 Let request be a request (e.g. a license request)
             //        generated based on the init data, which is interpreted
             //        per initDataType, and session type.
             m_session->initializeNewSession(action->initDataType(), static_cast<unsigned char*>(action->data()->data()), action->data()->byteLength(), m_sessionType, action->result()->result());
 
             // Remainder of steps executed in finishGenerateRequest(), called
             // when |result| is resolved.
             break;
 
+        case PendingAction::Load:
+            // NOTE: Continue step 8 of MediaKeySession::load().
+
+            // 8.1 Let sanitized session ID be a validated and/or sanitized
+            //     version of sessionId. The user agent should thoroughly
+            //     validate the sessionId value before passing it to the CDM.
+            //     At a minimum, this should include checking that the length
+            //     and value (e.g. alphanumeric) are reasonable.
+            // 8.2 If the previous step failed, reject promise with a new
+            //     DOMException whose name is "InvalidAccessError".
+            if (!ValidSessionId(action->sessionId())) {
+                action->result()->completeWithError(WebContentDecryptionModuleExceptionInvalidAccessError, 0, "Invalid sessionId");
+                return;
+            }
+
+            // 8.3 Let expiration time be NaN.
+            //     (Already done in the constructor.)
+            // TODO once expiration change merged in.

[sandersd (OOO until July 31), 2014/10/08 18:18:22]

I don't recall an expiration CL, perhaps this should just say "TODO: Implement
expiration."

[jrummell, 2014/10/08 21:13:20]

The other CL is https://codereview.chromium.org/621903003/. However, made more
generic (and a FIXME since that is what blink uses).

+            // ASSERT(std::isnan(m_expiration));
+
+            // 8.4 Let message be null.
+            // 8.5 Let message type be null.
+            //     (Will be provided by the CDM if needed.)
+
+            // 8.6 Let origin be the origin of this object's Document.
+            //     (Obtained previously when CDM created.)
+
+            // 8.7 Let cdm be the CDM loaded during the initialization of media
+            //     keys.
+            // 8.8 Use the cdm to execute the following steps:
+            // 8.8.1 If there is no data stored for the sanitized session ID in
+            //       the origin, resolve promise with false.
+            // 8.8.2 Let session data be the data stored for the sanitized
+            //       session ID in the origin. This must not include data from
+            //       other origin(s) or that is not associated with an origin.
+            // 8.8.3 If there is an unclosed "persistent" session in any
+            //       Document representing the session data, reject promise
+            //       with a new DOMException whose name is "QuotaExceededError".
+            // 8.8.4 In other words, do not create a session if a non-closed
+            //       persistent session already exists for this sanitized
+            //       session ID in any browsing context.
+            // 8.8.5 Load the session data.
+            // 8.8.6 If the session data indicates an expiration time for the
+            //       session, let expiration time be the expiration time
+            //       in milliseconds since 01 January 1970 UTC.
+            // 8.8.6 If the CDM needs to send a message:
+            // 8.8.6.1 Let message be a message generated by the CDM based on
+            //         the session data.
+            // 8.8.6.2 Let message type be the appropriate MediaKeyMessageType
+            //         for the message.
+            // 8.9 If any of the preceding steps failed, reject promise with a
+            //     new DOMException whose name is the appropriate error name.
+            m_session->loadSession(action->sessionId(), action->result()->result());
+
+            // Remainder of steps executed in finishLoadSession(), called
+            // when |result| is resolved.
+            break;
+
         case PendingAction::Update:
             WTF_LOG(Media, "MediaKeySession(%p)::actionTimerFired: Update", this);
             // NOTE: Continued from step 4 of MediaKeySession::update().
             // Continue the update call by passing message to the cdm. Once
             // completed, it will resolve/reject the promise.
             m_session->update(static_cast<unsigned char*>(action->data()->data()), action->data()->byteLength(), action->result()->result());
             break;
 
         case PendingAction::Release:
             WTF_LOG(Media, "MediaKeySession(%p)::actionTimerFired: Release", this);
@@ skipping 26 matching lines @@
     // https://www.w3.org/Bugs/Public/show_bug.cgi?id=26758
 
     // 10.7 Run the Queue a "message" Event algorithm on the session,
     //      providing request and null.
     //      (Done by the CDM).
 
     // 10.8 Let this object's callable be true.
     m_isCallable = true;
 }
 
+void MediaKeySession::finishLoadSession()
+{
+    // 8.10 Set the sessionId attribute to sanitized session ID.
+    ASSERT(!sessionId().isEmpty());
+
+    // 8.11 Let this object's callable be true.
+    m_isCallable = true;
+
+    // 8.12 If the loaded session contains usable keys, run the Usable
+    //      Keys Changed algorithm on the session. The algorithm may
+    //      also be run later should additional processing be necessary
+    //      to determine with certainty whether one or more keys is
+    //      usable.
+    //      (Done by the CDM.)
+
+    // 8.13 Run the Update Expiration algorithm on the session,
+    //      providing expiration time.
+    //      (Done by the CDM.)
+
+    // 8.14 If message is not null, run the Queue a "message" Event
+    //      algorithm on the session, providing message type and
+    //      message.
+    //      (Done by the CDM.)
+}
+
 // Queue a task to fire a simple event named keymessage at the new object.
 void MediaKeySession::message(const unsigned char* message, size_t messageLength, const WebURL& destinationURL)
 {
     WTF_LOG(Media, "MediaKeySession(%p)::message", this);
 
     // Verify that 'message' not fired before session initialization is complete.
     ASSERT(m_isCallable);
 
     MediaKeyMessageEventInit init;
     init.bubbles = false;
@@ skipping 117 matching lines @@
 {
     visitor->trace(m_error);
     visitor->trace(m_asyncEventQueue);
     visitor->trace(m_pendingActions);
     visitor->trace(m_mediaKeys);
     visitor->trace(m_closedPromise);
     EventTargetWithInlineData::trace(visitor);
 }
 
 } // namespace blink