Make WebMIDI use blink Promise.

Source/modules/webmidi/MIDIAccess.cpp

 /*
  * Copyright (C) 2013 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 13 matching lines @@
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "config.h"
 #include "modules/webmidi/MIDIAccess.h"
 
+#include "bindings/v8/MIDIAccessResolver.h"
+#include "bindings/v8/ScriptPromise.h"
+#include "bindings/v8/ScriptPromiseResolver.h"
+#include "bindings/v8/V8Binding.h"
 #include "core/dom/DOMError.h"
 #include "core/dom/Document.h"
 #include "core/loader/DocumentLoadTiming.h"
 #include "core/loader/DocumentLoader.h"
-#include "modules/webmidi/MIDIAccessPromise.h"
 #include "modules/webmidi/MIDIConnectionEvent.h"
 #include "modules/webmidi/MIDIController.h"
+#include "modules/webmidi/MIDIOptions.h"
 #include "modules/webmidi/MIDIPort.h"
+#include "platform/AsyncMethodRunner.h"
 
 namespace WebCore {
 
-PassRefPtrWillBeRawPtr<MIDIAccess> MIDIAccess::create(ExecutionContext* context, MIDIAccessPromise* promise)
+class MIDIAccess::PostAction : public ScriptFunction {
+public:
+    static PassOwnPtr<MIDIAccess::PostAction> create(v8::Isolate* isolate, MIDIAccess* owner, State state) { return adoptPtr(new PostAction(isolate, owner, state)); }
+
+private:
+    PostAction(v8::Isolate* isolate, MIDIAccess* owner, State state): ScriptFunction(isolate), m_owner(owner), m_state(state) { }
+    virtual ScriptValue call(ScriptValue value) OVERRIDE
+    {
+        m_owner->doPostAction(m_state);
+        return value;
+    }
+
+    // MIDIAccess must be accessible when |call| function is called.
+    MIDIAccess* m_owner;
+    State m_state;
+};
+
+ScriptPromise MIDIAccess::request(const MIDIOptions& options, ExecutionContext* context)
 {
-    RefPtrWillBeRawPtr<MIDIAccess> midiAccess(adoptRefWillBeRefCountedGarbageCollected(new MIDIAccess(context, promise)));
+    RefPtrWillBeRawPtr<MIDIAccess> midiAccess(adoptRefWillBeRefCountedGarbageCollected(new MIDIAccess(options, context)));
     midiAccess->suspendIfNeeded();
-    midiAccess->startRequest();
-    return midiAccess.release();
+    return midiAccess->startRequest();
 }
 
 MIDIAccess::~MIDIAccess()
 {
-    stop();
 }
 
-MIDIAccess::MIDIAccess(ExecutionContext* context, MIDIAccessPromise* promise)
+MIDIAccess::MIDIAccess(const MIDIOptions& options, ExecutionContext* context)
     : ActiveDOMObject(context)
-    , m_promise(promise)
-    , m_hasAccess(false)
+    , m_state(Requesting)
+    , m_options(options)
     , m_sysExEnabled(false)
-    , m_requesting(false)
+    , m_asyncResolveRunner(this, &MIDIAccess::resolveNow)
+    , m_asyncRejectRunner(this, &MIDIAccess::rejectNow)
 {
     ScriptWrappable::init(this);
     m_accessor = MIDIAccessor::create(this);
+    // Create a wrapper to expose this object to the V8 GC so that hasPendingActivity takes effect.
+    toV8NoInline(this, executionContext());

[haraken, 2014/03/13 02:22:33]

You might want to implement a helper method that does this hack.

Shall we create ActiveDOMObject::makeThisObjectAsynchronous() and add a good
comment into the method?

[yhirano, 2014/03/13 05:43:22]

It doesn't work because toV8NoInline can't be applied for ActiveDOMObject.

I'm planning to factor out this async-initialization operation to a class which
each Promise resolution target DOMObject can use, in the folowup CL.
The class will hide toV8NoInline from the customers.
So, I would keep it be.

+    // Now this object is retained because m_state equals to Requesting.
+    // startRequest should be called at once.
 }
 
 void MIDIAccess::setSysExEnabled(bool enable)
 {
-    m_requesting = false;
     m_sysExEnabled = enable;
-    if (enable)
+    if (enable) {
         m_accessor->startSession();
-    else
-        permissionDenied();
+    } else {
+        reject(DOMError::create("SecurityError"));
+    }
 }
 
 void MIDIAccess::didAddInputPort(const String& id, const String& manufacturer, const String& name, const String& version)
 {
     ASSERT(isMainThread());
 
     m_inputs.append(MIDIInput::create(this, id, manufacturer, name, version));
 }
 
 void MIDIAccess::didAddOutputPort(const String& id, const String& manufacturer, const String& name, const String& version)
 {
     ASSERT(isMainThread());
 
     unsigned portIndex = m_outputs.size();
     m_outputs.append(MIDIOutput::create(this, portIndex, id, manufacturer, name, version));
 }
 
 void MIDIAccess::didStartSession(bool success)
 {
     ASSERT(isMainThread());
-
-    m_hasAccess = success;
     if (success)
-        m_promise->fulfill();
+        resolve();
     else
-        m_promise->reject(DOMError::create("InvalidStateError"));
+        reject(DOMError::create("InvalidStateError"));
 }
 
 void MIDIAccess::didReceiveMIDIData(unsigned portIndex, const unsigned char* data, size_t length, double timeStamp)
 {
     ASSERT(isMainThread());
 
-    if (m_hasAccess && portIndex < m_inputs.size()) {
+    if (m_state == Resolved && portIndex < m_inputs.size()) {
         // Convert from time in seconds which is based on the time coordinate system of monotonicallyIncreasingTime()
         // into time in milliseconds (a DOMHighResTimeStamp) according to the same time coordinate system as performance.now().
         // This is how timestamps are defined in the Web MIDI spec.
         Document* document = toDocument(executionContext());
         ASSERT(document);
 
         double timeStampInMilliseconds = 1000 * document->loader()->timing()->monotonicTimeToZeroBasedDocumentTime(timeStamp);
 
         m_inputs[portIndex]->didReceiveMIDIData(portIndex, data, length, timeStampInMilliseconds);
     }
 }
 
 void MIDIAccess::sendMIDIData(unsigned portIndex, const unsigned char* data, size_t length, double timeStampInMilliseconds)
 {
-    if (m_hasAccess && portIndex < m_outputs.size() && data && length > 0) {
+    if (m_state == Resolved && portIndex < m_outputs.size() && data && length > 0) {
         // Convert from a time in milliseconds (a DOMHighResTimeStamp) according to the same time coordinate system as performance.now()
         // into a time in seconds which is based on the time coordinate system of monotonicallyIncreasingTime().
         double timeStamp;
 
         if (!timeStampInMilliseconds) {
             // We treat a value of 0 (which is the default value) as special, meaning "now".
             // We need to translate it exactly to 0 seconds.
             timeStamp = 0;
         } else {
             Document* document = toDocument(executionContext());
             ASSERT(document);
             double documentStartTime = document->loader()->timing()->referenceMonotonicTime();
             timeStamp = documentStartTime + 0.001 * timeStampInMilliseconds;
         }
 
         m_accessor->sendMIDIData(portIndex, data, length, timeStamp);
     }
 }
 
+void MIDIAccess::suspend()
+{
+    m_asyncResolveRunner.suspend();
+    m_asyncRejectRunner.suspend();
+}
+
+void MIDIAccess::resume()
+{
+    m_asyncResolveRunner.resume();
+    m_asyncRejectRunner.resume();
+}
+
 void MIDIAccess::stop()
 {
-    m_hasAccess = false;
-    if (!m_requesting)
+    if (m_state == Stopped)
         return;
-    m_requesting = false;
-    Document* document = toDocument(executionContext());
-    ASSERT(document);
-    MIDIController* controller = MIDIController::from(document->page());
-    ASSERT(controller);
-    controller->cancelSysExPermissionRequest(this);
+    m_error.clear();
+    m_accessor.clear();
+    m_asyncResolveRunner.stop();
+    m_asyncRejectRunner.stop();
+    if (m_state == Requesting) {
+        Document* document = toDocument(executionContext());
+        ASSERT(document);
+        MIDIController* controller = MIDIController::from(document->page());
+        ASSERT(controller);
+        controller->cancelSysExPermissionRequest(this);
+    }
+    m_state = Stopped;
 }
 
-void MIDIAccess::startRequest()
+bool MIDIAccess::hasPendingActivity() const
 {
-    if (!m_promise->options()->sysex) {
+    return m_state == Requesting;
+}
+
+void MIDIAccess::permissionDenied()
+{
+    ASSERT(isMainThread());
+    reject(DOMError::create("SecurityError"));
+}
+
+ScriptPromise MIDIAccess::startRequest()
+{
+    ScriptPromise promise = ScriptPromise::createPending();

[haraken, 2014/03/13 02:22:33]

Shall we add ASSERT(frame()) ?

[yhirano, 2014/03/13 05:43:22]

Done.

+    promise.then(PostAction::create(toIsolate(executionContext()), this, Resolved),
+        PostAction::create(toIsolate(executionContext()), this, Stopped));
+
+    m_resolver = MIDIAccessResolver::create(ScriptPromiseResolver::create(promise, executionContext()), executionContext());
+    if (!m_options.sysex) {
         m_accessor->startSession();
-        return;
+        return promise;
     }
     Document* document = toDocument(executionContext());
     ASSERT(document);
     MIDIController* controller = MIDIController::from(document->page());
     if (controller) {
-        m_requesting = true;
         controller->requestSysExPermission(this);
     } else {
-        permissionDenied();
+        reject(DOMError::create("SecurityError"));
     }
+    return promise;
 }
 
-void MIDIAccess::permissionDenied()
+void MIDIAccess::resolve()
 {
-    ASSERT(isMainThread());
+    m_asyncResolveRunner.runAsync();
+}
 
-    m_hasAccess = false;
-    m_promise->reject(DOMError::create("SecurityError"));
+void MIDIAccess::reject(PassRefPtr<DOMError> error)
+{
+    m_error = error;
+    m_asyncRejectRunner.runAsync();
+}
+
+void MIDIAccess::resolveNow()
+{
+    m_resolver->resolve(this, executionContext());
+}
+
+void MIDIAccess::rejectNow()
+{
+    m_resolver->reject(m_error.release().get(), executionContext());
+}
+
+void MIDIAccess::doPostAction(State state)
+{
+    ASSERT(m_state == Requesting);
+    ASSERT(state == Resolved || state == Stopped);
+    m_error.clear();
+    if (state == Stopped) {
+        m_accessor.clear();
+    }
+    m_state = state;
 }
 
 void MIDIAccess::trace(Visitor* visitor)
 {
     visitor->trace(m_inputs);
     visitor->trace(m_outputs);
-    visitor->trace(m_promise);
 }
 
 } // namespace WebCore