Make WebMIDI use blink Promise.

Source/modules/webmidi/NavigatorWebMIDI.cpp

Index: Source/modules/webmidi/NavigatorWebMIDI.cpp
diff --git a/Source/modules/webmidi/NavigatorWebMIDI.cpp b/Source/modules/webmidi/NavigatorWebMIDI.cpp
index 87f7b25d31ef0fbc61ed12c4644be689c87b3033..db5ac9872c911872a4aab79e3b08066a750227c1 100644
--- a/Source/modules/webmidi/NavigatorWebMIDI.cpp
+++ b/Source/modules/webmidi/NavigatorWebMIDI.cpp
@@ -31,11 +31,16 @@
 #include "config.h"
 #include "modules/webmidi/NavigatorWebMIDI.h"
 
+#include "bindings/v8/DOMRequestState.h"
+#include "bindings/v8/ScriptPromise.h"
+#include "bindings/v8/ScriptPromiseResolver.h"
+#include "core/dom/DOMError.h"
 #include "core/dom/Document.h"
 #include "core/dom/ExecutionContext.h"
 #include "core/frame/Frame.h"
 #include "core/frame/Navigator.h"
-#include "modules/webmidi/MIDIAccessPromise.h"
+#include "modules/webmidi/MIDIAccess.h"
+#include "modules/webmidi/MIDIOptions.h"
 
 namespace WebCore {
 
@@ -46,6 +51,7 @@ NavigatorWebMIDI::NavigatorWebMIDI(Frame* frame)
 
 NavigatorWebMIDI::~NavigatorWebMIDI()
 {
+    clearPending();
 }
 
 const char* NavigatorWebMIDI::supplementName()
@@ -63,20 +69,85 @@ NavigatorWebMIDI* NavigatorWebMIDI::from(Navigator* navigator)
     return supplement;
 }
 
-PassRefPtr<MIDIAccessPromise> NavigatorWebMIDI::requestMIDIAccess(Navigator* navigator, const Dictionary& options)
+ScriptPromise NavigatorWebMIDI::requestMIDIAccess(Navigator* navigator, const Dictionary& options)
 {
     return NavigatorWebMIDI::from(navigator)->requestMIDIAccess(options);
 }
 
-PassRefPtr<MIDIAccessPromise> NavigatorWebMIDI::requestMIDIAccess(const Dictionary& options)
+ScriptPromise NavigatorWebMIDI::requestMIDIAccess(const Dictionary& options)
 {
-    if (!frame())
-        return 0;
+    if (!frame()) {
+        ScriptPromise promise = ScriptPromise::createPending();
+        RefPtr<ScriptPromiseResolver> resolver = ScriptPromiseResolver::create(promise);
+        // FIXME: Currently this rejection does not work because the context is stopped.
+        resolver->reject(DOMError::create("AbortError"));

[abarth-chromium, 2013/12/03 16:57:57]

Maybe we should throw an exception instead?

[yhirano, 2013/12/04 05:20:24]

I think the spec doesn't want to throw an error except TypeError. toyoshim@,
what do you think?
http://webaudio.github.io/web-midi-api/#requestmidiaccess

[Takashi Toyoshima, 2013/12/04 06:48:37]

How about other Promise or asynchronous API usages?
I guess handling all kind of errors in the error callback is easy for JavaScript
developer to handle them when they use Promise or asynchronous APIs.

[yhirano, 2013/12/05 08:19:12]

I think so as well.
Anyway, this may be a Promise bug. I will try to fix it...

+        return promise;
+    }
 
     ExecutionContext* context = frame()->document();
     ASSERT(context);
+    if (!m_requestState.get())
+        m_requestState = adoptPtr(new DOMRequestState(context));

[abarth-chromium, 2013/12/03 16:57:57]

Why is there only one m_requestState?  When is m_requestState cleared? 
DOMRequestState holds a DOMWrapperWorld.  What if this function is called from
multiple worlds?  You'll call the callback in the wrong world.

[yhirano, 2013/12/04 05:20:24]

Done.
Now each MIDIAccessor has its DOMRequestState.

+    ScriptPromise promise = ScriptPromise::createPending(context);
+    RefPtr<MIDIAccess> access = MIDIAccess::create(MIDIOptions(options), context, this);
+    m_pending.add(access, ScriptPromiseResolver::create(promise, context));
+    access->startRequest();
+    return promise;
+}
+
+void NavigatorWebMIDI::didFinishRequest(MIDIAccess* access)
+{
+    // FIXME: We should care about suspend / stop.
+    RefPtr<MIDIAccess> key(access);
+    if (!m_pending.contains(key))
+        return;
+    RefPtr<ScriptPromiseResolver> resolver = m_pending.get(key);
+    m_pending.remove(key);
+
+    if (!frame()) {
+        // We can break the promise if the frame does not exist.
+        return;
+    }
+    ASSERT(m_requestState);
+    DOMRequestState::Scope scope(*m_requestState);
+    resolver->resolve(access, access->executionContext());
+}
+
+void NavigatorWebMIDI::didFailRequest(MIDIAccess* access, PassRefPtr<DOMError> error)
+{
+    // FIXME: We should care about suspend / stop.
+    RefPtr<MIDIAccess> key(access);
+    if (!m_pending.contains(key))
+        return;
+    RefPtr<ScriptPromiseResolver> resolver = m_pending.get(key);
+    m_pending.remove(key);
+    if (!frame()) {
+        // We can break the promise if the frame does not exist.
+        return;
+    }
+    ASSERT(m_requestState);
+    DOMRequestState::Scope scope(*m_requestState);
+    resolver->reject(error, access->executionContext());
+}
+
+void NavigatorWebMIDI::clearPending()
+{
+    // FIXME: We should care about suspend / stop.
+    HashMap<RefPtr<MIDIAccess>, RefPtr<ScriptPromiseResolver> > pending;
+    pending.swap(m_pending);
+
+    if (!frame()) {
+        // We can break promises if the frame does not exist.
+        return;
+    }
 
-    return MIDIAccessPromise::create(context, options);
+    ASSERT(m_requestState);
+    for (HashMap<RefPtr<MIDIAccess>, RefPtr<ScriptPromiseResolver> >::iterator i = pending.begin();
+        i != pending.end(); ++i) {
+        DOMRequestState::Scope scope(*m_requestState);
+        MIDIAccess* access = i->key.get();
+        i->value->reject(DOMError::create("AbortError"), access->executionContext());
+    }
 }
 
 } // namespace WebCore