Decouple MIDIAccess initialization from MIDIAccess class.

Source/modules/webmidi/MIDIAccessInitializer.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/webmidi/MIDIAccessInitializer.h"
+
+#include "bindings/v8/ScriptFunction.h"
+#include "bindings/v8/ScriptPromise.h"
+#include "bindings/v8/ScriptPromiseResolverWithContext.h"
+#include "core/dom/DOMError.h"
+#include "core/dom/Document.h"
+#include "modules/webmidi/MIDIAccess.h"
+#include "modules/webmidi/MIDIController.h"
+#include "modules/webmidi/MIDIOptions.h"
+
+namespace WebCore {
+
+class MIDIAccessInitializer::PostAction : public ScriptFunction {
+public:
+    static PassOwnPtr<MIDIAccessInitializer::PostAction> create(v8::Isolate* isolate, WeakPtr<MIDIAccessInitializer> owner, State state) { return adoptPtr(new PostAction(isolate, owner, state)); }
+
+private:
+    PostAction(v8::Isolate* isolate, WeakPtr<MIDIAccessInitializer> owner, State state): ScriptFunction(isolate), m_owner(owner), m_state(state) { }
+    virtual ScriptValue call(ScriptValue value) OVERRIDE
+    {
+        if (!m_owner.get())
+            return value;
+        m_owner->doPostAction(m_state);
+        return value;
+    }
+
+    WeakPtr<MIDIAccessInitializer> m_owner;
+    State m_state;
+};
+
+MIDIAccessInitializer::~MIDIAccessInitializer()
+{
+    ASSERT(m_state != Requesting);
+}
+
+MIDIAccessInitializer::MIDIAccessInitializer(const MIDIOptions& options, MIDIAccess* access)
+    : m_state(Requesting)
+    , m_weakPtrFactory(this)
+    , m_options(options)
+    , m_sysexEnabled(false)
+    , m_access(access)
+{
+    m_accessor = MIDIAccessor::create(this);
+}
+
+void MIDIAccessInitializer::didAddInputPort(const String& id, const String& manufacturer, const String& name, const String& version)
+{
+    m_access->didAddInputPort(id, manufacturer, name, version);
+}
+
+void MIDIAccessInitializer::didAddOutputPort(const String& id, const String& manufacturer, const String& name, const String& version)
+{
+    m_access->didAddOutputPort(id, manufacturer, name, version);
+}
+
+void MIDIAccessInitializer::didStartSession(bool success, const String& error, const String& message)
+{
+    if (success)
+        m_resolver->resolve(m_access);
+    else
+        m_resolver->reject(DOMError::create(error, message));
+}
+
+void MIDIAccessInitializer::setSysexEnabled(bool enable)
+{
+    m_sysexEnabled = enable;
+    if (enable) {

[Takashi Toyoshima, 2014/06/04 22:03:53]

It is not changed from the original, but parentheses for one liners are not
consistent with others. Can you change this to be consistent?

[yhirano, 2014/06/05 11:35:25]

Done.

+        m_accessor->startSession();
+    } else {
+        m_resolver->reject(DOMError::create("SecurityError"));
+    }
+}
+
+SecurityOrigin* MIDIAccessInitializer::securityOrigin() const
+{
+    return m_access->executionContext()->securityOrigin();
+}
+
+void MIDIAccessInitializer::cancel()
+{
+    if (m_state != Requesting)
+        return;
+    m_accessor.clear();
+    m_weakPtrFactory.revokeAll();
+    Document* document = toDocument(executionContext());
+    ASSERT(document);
+    MIDIController* controller = MIDIController::from(document->page());
+    ASSERT(controller);
+    controller->cancelSysexPermissionRequest(this);

[Takashi Toyoshima, 2014/06/04 22:03:53]

Related to a comment on WebMIDIPermissionRequest.h.
I guess this ensures that MIDIAccessInitializer lives longer than
WebMIDIPermissionRequest, right?

[yhirano, 2014/06/05 11:35:25]

Yes, request must not outlive the initializer and calling cancel ensures it.

+    m_state = Stopped;
+}
+
+ExecutionContext* MIDIAccessInitializer::executionContext() const
+{
+    return m_access->executionContext();
+}
+
+void MIDIAccessInitializer::permissionDenied()
+{
+    ASSERT(isMainThread());
+    m_resolver->reject(DOMError::create("SecurityError"));
+}
+
+ScriptPromise MIDIAccessInitializer::initialize(ScriptState* scriptState)
+{
+    m_resolver = ScriptPromiseResolverWithContext::create(scriptState);
+    ScriptPromise promise = m_resolver->promise();
+    promise.then(PostAction::create(scriptState->isolate(), m_weakPtrFactory.createWeakPtr(), Resolved),
+        PostAction::create(scriptState->isolate(), m_weakPtrFactory.createWeakPtr(), Stopped));
+
+    if (!m_options.sysex) {
+        m_accessor->startSession();
+        return promise;
+    }
+    Document* document = toDocument(executionContext());
+    ASSERT(document);
+    MIDIController* controller = MIDIController::from(document->page());
+    if (controller) {
+        controller->requestSysexPermission(this);
+    } else {
+        m_resolver->reject(DOMError::create("SecurityError"));
+    }
+    return promise;
+}
+
+void MIDIAccessInitializer::doPostAction(State state)
+{
+    ASSERT(m_state == Requesting);
+    ASSERT(state == Resolved || state == Stopped);
+    if (state == Resolved) {
+        m_access->initialize(m_accessor.release(), m_sysexEnabled);
+    }
+    m_accessor.clear();
+    m_weakPtrFactory.revokeAll();
+    m_state = state;
+}
+
+} // namespace WebCore