MediaRecorder Blink part

Source/modules/mediarecorder/MediaRecorder.cpp

+// Copyright 2015 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/mediarecorder/MediaRecorder.h"
+
+#include "core/dom/DOMError.h"
+#include "core/fileapi/Blob.h"
+#include "modules/EventModules.h"
+#include "modules/EventTargetModules.h"
+#include "modules/mediarecorder/MediaRecorderErrorEvent.h"
+#include "platform/blob/BlobData.h"
+#include "public/platform/Platform.h"
+#include "public/platform/WebMediaStream.h"
+
+namespace blink {
+
+namespace {
+
+static String stateToString(MediaRecorder::State state)
+{
+    switch (state) {
+    case MediaRecorder::State::Inactive:
+        return "inactive";
+    case MediaRecorder::State::Recording:
+        return "recording";
+    case MediaRecorder::State::Paused:
+        return "paused";
+    }
+
+    ASSERT_NOT_REACHED();
+    return String();
+}
+
+} // namespace
+
+MediaRecorder* MediaRecorder::create(ExecutionContext* context, MediaStream* stream, ExceptionState& exceptionState)
+{
+    MediaRecorder* recorder = new MediaRecorder(context, stream, String(), exceptionState);
+    recorder->suspendIfNeeded();
+
+    return recorder;
+}
+
+MediaRecorder* MediaRecorder::create(ExecutionContext* context, MediaStream* stream,  const String& mimeType, ExceptionState& exceptionState)
+{
+    MediaRecorder* recorder = new MediaRecorder(context, stream, mimeType, exceptionState);
+    recorder->suspendIfNeeded();
+
+    return recorder;
+}
+
+MediaRecorder::MediaRecorder(ExecutionContext* context, MediaStream* stream, const String& mimeType, ExceptionState& exceptionState)
+    : ActiveDOMObject(context)
+    , m_stream(stream)
+    , m_mimeType(mimeType)
+    , m_stopped(true)
+    , m_ignoreMutedMedia(true)

[Peter Beverloo, 2015/09/01 17:17:12]

We currently don't use this property, and only reflect it in JavaScript, right?
Will we support it eventually?

It would be good to add a TODO to make sure we don't forget about this.

[mcasas, 2015/09/02 03:10:17]

Done.

+    , m_state(State::Inactive)
+    , m_dispatchScheduledEventRunner(this, &MediaRecorder::dispatchScheduledEvent)
+{
+    m_recorderHandler = adoptPtr(Platform::current()->createMediaRecorderHandler());
+
+    // TODO(mcasas): Once http://crbug.com/262211 has landed the Chromium parts,
+    // and more concretetely the createMediaRecorderHandler() implementation,
+    // ASSERT() here for |m_recorderHandler|.
+    if (!m_recorderHandler) {
+        exceptionState.throwDOMException(NotSupportedError, "No MediaRecorder handler can be created.");
+        return;
+    }
+
+    if (!m_recorderHandler->initialize(this, stream->descriptor(), m_mimeType)) {
+        exceptionState.throwDOMException(NotSupportedError, "Failed to initialize native MediaRecorder.");

[Peter Beverloo, 2015/09/01 17:17:12]

The specification states the following:

"If the UA does not support the format or any of the parameters specified, it
must raise an UnsupportedOption Exception."

Putting aside the UnsupportedOption bit (I replied to one of your GitHub
issues), throwing a NotSupportedError in that case seems good. I would, however,
like to see a clearer error message, so that developers know what's going on.

Perhaps copy the MediaSource message? ("The type provided (..m_mimeType..) is
unsupported.")

[mcasas, 2015/09/02 03:10:18]

Done.

+        return;
+    }
+    m_stopped = false;
+}
+
+String MediaRecorder::state() const
+{
+    return stateToString(m_state);
+}
+
+void MediaRecorder::start(ExceptionState& exceptionState)
+{
+    if (m_state != State::Inactive) {
+        exceptionState.throwDOMException(InvalidStateError, "The MediaRecorder's state is '" + stateToString(m_state) + "'.");
+        return;
+    }
+    m_state = State::Recording;
+
+    m_recorderHandler->start();
+}
+
+void MediaRecorder::start(int timeSlice, ExceptionState& exceptionState)
+{
+    if (m_state != State::Inactive) {
+        exceptionState.throwDOMException(InvalidStateError, "The MediaRecorder's state is '" + stateToString(m_state) + "'.");
+        return;
+    }
+    m_state = State::Recording;
+
+    m_recorderHandler->start(timeSlice);
+}
+
+void MediaRecorder::stop(ExceptionState& exceptionState)
+{
+    if (m_state == State::Inactive) {
+        exceptionState.throwDOMException(InvalidStateError, "The MediaRecorder's state is '" + stateToString(m_state) + "'.");
+        return;
+    }
+
+    stopRecording();
+}
+
+void MediaRecorder::pause(ExceptionState& exceptionState)
+{
+    if (m_state == State::Inactive) {
+        exceptionState.throwDOMException(InvalidStateError, "The MediaRecorder's state is '" + stateToString(m_state) + "'.");
+        return;
+    }
+    if (m_state == State::Paused)
+        return;
+
+    m_state = State::Paused;
+
+    m_recorderHandler->pause();
+
+    scheduleDispatchEvent(Event::create(EventTypeNames::pause));
+}
+
+void MediaRecorder::resume(ExceptionState& exceptionState)
+{
+    if (m_state == State::Inactive) {
+        exceptionState.throwDOMException(InvalidStateError, "The MediaRecorder's state is '" + stateToString(m_state) + "'.");
+        return;
+    }
+    if (m_state == State::Recording)
+        return;
+
+    m_state = State::Recording;
+
+    m_recorderHandler->resume();
+}
+
+void MediaRecorder::requestData(ExceptionState& exceptionState)
+{
+    if (m_state != State::Recording) {
+        exceptionState.throwDOMException(InvalidStateError, "The MediaRecorder's state is '" + stateToString(m_state) + "'.");
+        return;
+    }
+
+    createBlobEvent(BlobData::create());
+}
+
+String MediaRecorder::canRecordMimeType(const String& mimeType)
+{
+    RawPtr<WebMediaRecorderHandler> handler = Platform::current()->createMediaRecorderHandler();
+    if (!handler)
+        return emptyString();
+
+    // MediaRecorder canRecordMimeType() MUST return 'probably' "if the UA is
+    // confident that mimeType represents a type that it can record" [1], but a
+    // number of reasons could prevent the recording from happening as expected,
+    // so 'maybe' is a better option: "Implementors are encouraged to return
+    // "maybe" unless the type can be confidently established as being supported
+    // or not.". Hence this method returns '' or 'maybe', never 'probably'.
+    // [1] http://w3c.github.io/mediacapture-record/MediaRecorder.html#methods
+    return handler->canSupportMimeType(mimeType) ? "maybe" : emptyString();
+}
+
+const AtomicString& MediaRecorder::interfaceName() const
+{
+    return EventTargetNames::MediaRecorder;
+}
+
+ExecutionContext* MediaRecorder::executionContext() const
+{
+    return ActiveDOMObject::executionContext();
+}
+
+void MediaRecorder::suspend()
+{
+    m_dispatchScheduledEventRunner.suspend();
+}
+
+void MediaRecorder::resume()
+{
+    m_dispatchScheduledEventRunner.resume();
+}
+
+void MediaRecorder::stop()
+{
+    if (m_stopped)
+        return;
+
+    m_stopped = true;
+    m_stream.clear();
+    m_recorderHandler.clear();
+
+    scheduleDispatchEvent(Event::create(EventTypeNames::stop));
+}
+
+void MediaRecorder::writeData(const char* data, size_t length, bool lastInSlice)
+{
+    ASSERT(m_state == State::Recording);
+
+    if (m_stopped) {
+        m_stopped = false;
+        scheduleDispatchEvent(Event::create(EventTypeNames::start));
+    }
+
+    // TODO(mcasas): Use |lastInSlice| to indicate to JS that recording is done.
+
+    OwnPtr<BlobData> blobData = BlobData::create();
+    blobData->appendBytes(data, length);
+    createBlobEvent(blobData.release());
+}
+
+void MediaRecorder::failOutOfMemory(const WebString& message)
+{
+    scheduleDispatchEvent(MediaRecorderErrorEvent::create(

[Peter Beverloo, 2015/09/01 17:17:12]

nit: note that you don't have to wrap the line. I don't mind too much either
way.

[mcasas, 2015/09/02 03:10:17]

Acknowledged.

+        EventTypeNames::error, false, false, "OutOfMemory", message));
+
+    if (m_state == State::Recording)
+        stopRecording();
+}
+
+void MediaRecorder::failIllegalStreamModification(const WebString& message)
+{
+    scheduleDispatchEvent(MediaRecorderErrorEvent::create(
+        EventTypeNames::error, false, false, "IllegalStreamModification", message));
+
+    if (m_state == State::Recording)
+        stopRecording();
+}
+
+void MediaRecorder::failOtherRecordingError(const WebString& message)
+{
+    scheduleDispatchEvent(MediaRecorderErrorEvent::create(
+        EventTypeNames::error, false, false, "OtherRecordingError", message));
+
+    if (m_state == State::Recording)
+        stopRecording();
+}
+
+void MediaRecorder::createBlobEvent(PassOwnPtr<BlobData> blobData)
+{
+    // TODO(mcasas): Launch a BlobEvent when that class is landed.
+    ASSERT_NOT_REACHED();
+}
+
+void MediaRecorder::stopRecording()
+{
+    ASSERT(m_state != State::Inactive);
+    m_state = State::Inactive;
+
+    m_recorderHandler->stop();
+
+    createBlobEvent(BlobData::create());
+
+    scheduleDispatchEvent(Event::create(EventTypeNames::stop));
+}
+
+void MediaRecorder::scheduleDispatchEvent(PassRefPtrWillBeRawPtr<Event> event)
+{
+    m_scheduledEvents.append(event);
+
+    m_dispatchScheduledEventRunner.runAsync();
+}
+
+void MediaRecorder::dispatchScheduledEvent()
+{
+    WillBeHeapVector<RefPtrWillBeMember<Event>> events;
+    events.swap(m_scheduledEvents);
+
+    WillBeHeapVector<RefPtrWillBeMember<Event>>::iterator it = events.begin();
+    for (; it != events.end(); ++it)
+        dispatchEvent((*it).release());
+
+    events.clear();
+}
+
+DEFINE_TRACE(MediaRecorder)
+{
+    visitor->trace(m_stream);
+    RefCountedGarbageCollectedEventTargetWithInlineData<MediaRecorder>::trace(visitor);
+    ActiveDOMObject::trace(visitor);
+}
+
+} // namespace blink