Implement PromiseResolver.prototype.{fulfill, reject}

Source/bindings/v8/custom/V8PromiseCustom.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 15 matching lines @@
  * 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 "bindings/v8/custom/V8PromiseCustom.h"
 
 #include "V8Promise.h"
 #include "V8PromiseResolver.h"
+#include "bindings/v8/ScopedPersistent.h"
+#include "bindings/v8/ScriptFunctionCall.h"
 #include "bindings/v8/V8Binding.h"
+#include "bindings/v8/V8PerIsolateData.h"
 #include "bindings/v8/V8ScriptRunner.h"
 #include "bindings/v8/WrapperTypeInfo.h"
+#include "core/dom/Document.h"
+#include "core/dom/ExceptionCode.h"
+#include "core/page/DOMWindow.h"
+#include "core/platform/Task.h"
+#include "wtf/Functional.h"
+#include "wtf/PassOwnPtr.h"
 #include <v8.h>
 
 namespace WebCore {
 
+namespace {
+
+class PromiseTask : public ScriptExecutionContext::Task {
+public:
+    PromiseTask(v8::Handle<v8::Function> callback, v8::Handle<v8::Object> receiver, v8::Handle<v8::Value> result)
+        : m_callback(callback)
+        , m_receiver(receiver)
+        , m_result(result)
+    {
+        ASSERT(!callback.IsEmpty());
+        ASSERT(!receiver.IsEmpty());
+        ASSERT(!result.IsEmpty());

[abarth-chromium, 2013/06/27 06:34:01]

You can check the m_ versions of these, if you like.

[yhirano, 2013/06/27 09:29:23]

Done.

+    }
+    virtual ~PromiseTask() { }
+
+    virtual void performTask(ScriptExecutionContext*) OVERRIDE;
+
+private:
+    ScopedPersistent<v8::Function> m_callback;
+    ScopedPersistent<v8::Object> m_receiver;
+    ScopedPersistent<v8::Value> m_result;
+};
+
+void PromiseTask::performTask(ScriptExecutionContext* context)
+{
+    if (context->activeDOMObjectsAreStopped())
+        return;
+    ASSERT(context->isDocument());

[haraken, 2013/06/27 06:55:56]

Nit: You can move this check to the head of this method. ASSERT(context &&
context->isDocument()) would be better.

[yhirano, 2013/06/27 09:29:23]

Done.

+    ScriptState* state = mainWorldScriptState(static_cast<Document*>(context)->frame());
+    v8::HandleScope handleScope;
+    ASSERT(state);
+    v8::Handle<v8::Context> v8Context = state->context();
+    ASSERT(!v8Context.IsEmpty());
+    v8::Context::Scope scope(v8Context);
+    v8::Isolate* isolate = v8Context->GetIsolate();
+    ASSERT(!m_callback.newLocal(isolate).IsEmpty());
+    ASSERT(!m_receiver.newLocal(isolate).IsEmpty());
+    ASSERT(!m_result.newLocal(isolate).IsEmpty());

[abarth-chromium, 2013/06/27 06:34:01]

No need to call newLocal here.  ScopedPersistent has an isEmpty() function.

[yhirano, 2013/06/27 09:29:23]

I deleted the ASSERTs.

+    v8::Handle<v8::Value> result = m_result.newLocal(isolate);
+    V8ScriptRunner::callFunction(m_callback.newLocal(isolate), context, m_receiver.newLocal(isolate), 1, &result);

[haraken, 2013/06/27 06:55:56]

Nit: We normally write this as follows:

  v8::Handle<v8::Value> args[] = { result };
  V8ScriptRunner::callFunction(..., WTF_ARRAY_LENGTH(args), args);

[yhirano, 2013/06/27 09:29:23]

Done.

+};
+
+v8::Handle<v8::Value> postTask(v8::Handle<v8::Function> callback, v8::Handle<v8::Object> receiver, v8::Handle<v8::Value> value, v8::Isolate* isolate)
+{
+    DOMWindow* window = activeDOMWindow();
+    ASSERT(window);
+    Document* document = window->document();
+    ASSERT(document);
+    document->postTask(adoptPtr(new PromiseTask(callback, receiver, value)));
+    return v8::Undefined(isolate);
+}
+
+} // namespace
+
 void V8Promise::constructorCustom(const v8::FunctionCallbackInfo<v8::Value>& args)
 {
     v8SetReturnValue(args, v8::Local<v8::Value>());
     v8::Isolate* isolate = args.GetIsolate();
     if (!args.Length() || args[0].IsEmpty() || !args[0]->IsFunction()) {
         throwTypeError("Promise constructor takes a function argument", isolate);
         return;
     }
-    v8::Handle<v8::Function> init = args[0].As<v8::Function>();
-    v8::Local<v8::ObjectTemplate> internalTemplate = v8::ObjectTemplate::New();
-    internalTemplate->SetInternalFieldCount(V8PromiseCustom::InternalFieldCount);
-    v8::Local<v8::Object> internal = internalTemplate->NewInstance();
-    v8::Local<v8::Object> promise = V8DOMWrapper::createWrapper(args.Holder(), &V8Promise::info, 0, isolate);
-    v8::Local<v8::Object> promiseResolver = V8DOMWrapper::createWrapper(args.Holder(), &V8PromiseResolver::info, 0, isolate);
-
-    internal->SetInternalField(V8PromiseCustom::InternalStateIndex, v8::NumberObject::New(V8PromiseCustom::Pending));
-    internal->SetInternalField(V8PromiseCustom::InternalResultIndex, v8::Undefined());
-    internal->SetInternalField(V8PromiseCustom::InternalFulfillCallbackIndex, v8::Array::New());
-    internal->SetInternalField(V8PromiseCustom::InternalRejectCallbackIndex, v8::Array::New());
-
-    promise->SetInternalField(v8DOMWrapperObjectIndex, internal);
-    promiseResolver->SetInternalField(v8DOMWrapperObjectIndex, internal);
-
+    v8::Local<v8::Function> init = args[0].As<v8::Function>();
+    v8::Local<v8::Object> promise, resolver;
+    V8PromiseCustom::createPromise(args.Holder(), &promise, &resolver, isolate);
     v8::Handle<v8::Value> argv[] = {
-        promiseResolver,
+        resolver,
     };
     v8::TryCatch trycatch;
     if (V8ScriptRunner::callFunction(init, getScriptExecutionContext(), promise, WTF_ARRAY_LENGTH(argv), argv).IsEmpty()) {
-        // FIXME: An exception is thrown. Reject the promise.
+        // An exception is thrown. Reject the promise.
+        V8PromiseCustom::rejectResolver(resolver, trycatch.Exception(), V8PromiseCustom::Asynchronous, isolate);
     }
     v8SetReturnValue(args, promise);
     return;
 }
 
+//
+// -- V8PromiseCustom --
+void V8PromiseCustom::createPromise(v8::Handle<v8::Object> creationContext, v8::Local<v8::Object>* promise, v8::Local<v8::Object>* resolver, v8::Isolate* isolate)
+{
+    // FIXME: v8::ObjectTemplate::New should be cached.
+    v8::Local<v8::ObjectTemplate> internalTemplate = v8::ObjectTemplate::New();
+    internalTemplate->SetInternalFieldCount(InternalFieldCount);
+    v8::Local<v8::Object> internal = internalTemplate->NewInstance();
+    *promise = V8DOMWrapper::createWrapper(creationContext, &V8Promise::info, 0, isolate);
+    *resolver = V8DOMWrapper::createWrapper(creationContext, &V8PromiseResolver::info, 0, isolate);
+
+    clearInternal(internal, V8PromiseCustom::Pending, v8::Undefined(isolate));
+
+    (*promise)->SetInternalField(v8DOMWrapperObjectIndex, internal);
+    (*resolver)->SetInternalField(v8DOMWrapperObjectIndex, internal);
+}
+
+void V8PromiseCustom::fulfillResolver(v8::Handle<v8::Object> resolver, v8::Handle<v8::Value> result, SynchronousMode mode, v8::Isolate* isolate)
+{
+    ASSERT(!resolver.IsEmpty());
+    ASSERT(!result.IsEmpty());
+    v8::Local<v8::Object> internal = getInternal(resolver);
+    if (internal.IsEmpty() || getState(internal) != Pending) {
+        // The resolver is already fulfilled or rejected.
+        return;
+    }
+
+    v8::Local<v8::Value> value;
+    value = internal->GetInternalField(V8PromiseCustom::InternalFulfillCallbackIndex);

[abarth-chromium, 2013/06/27 06:34:01]

You can combine these lines.

[yhirano, 2013/06/27 09:29:23]

Done.

+    ASSERT(!value.IsEmpty());
+    ASSERT(value->IsArray());
+    v8::Local<v8::Array> callbacks = value.As<v8::Array>();
+    clearInternal(internal, Fulfilled, result);
+    // The internal object is no more needed in this PromiseResolver.
+    resolver->SetInternalField(v8DOMWrapperObjectIndex, v8::Null(isolate));
+
+    v8::Local<v8::Object> global = isolate->GetCurrentContext()->Global();
+    for (uint32_t i = 0, length = callbacks->Length(); i < length; ++i) {
+        value = callbacks->Get(i);
+        ASSERT(!value.IsEmpty());
+        ASSERT(value->IsFunction());
+        v8::Local<v8::Function> callback = value.As<v8::Function>();
+        call(callback, global, result, mode, isolate);

[abarth-chromium, 2013/06/27 06:34:01]

Do we need to check for exceptions?

[yhirano, 2013/06/27 09:29:23]

V8PromiseCustom::call doesn't throws an exception, as stated in the header
comment.

+    }
+}
+
+void V8PromiseCustom::rejectResolver(v8::Handle<v8::Object> resolver, v8::Handle<v8::Value> result, SynchronousMode mode, v8::Isolate* isolate)

[abarth-chromium, 2013/06/27 06:34:01]

Can we share more code between this function and fulfillResolver?  They seem to
be doing basically the same things.

[yhirano, 2013/06/27 09:29:23]

Done.

+{
+    ASSERT(!resolver.IsEmpty());
+    ASSERT(!result.IsEmpty());
+    v8::Local<v8::Object> internal = getInternal(resolver);
+    if (internal.IsEmpty() || getState(internal) != Pending) {
+        // The resolver is already fulfilled or rejected.
+        return;
+    }
+
+    v8::Local<v8::Value> value;
+    value = internal->GetInternalField(V8PromiseCustom::InternalRejectCallbackIndex);
+    ASSERT(!value.IsEmpty());
+    ASSERT(value->IsArray());
+    v8::Local<v8::Array> callbacks = value.As<v8::Array>();
+    clearInternal(internal, Rejected, result);
+    // The internal object is no more needed in this PromiseResolver.
+    resolver->SetInternalField(v8DOMWrapperObjectIndex, v8::Null(isolate));
+
+    v8::Local<v8::Object> global = isolate->GetCurrentContext()->Global();
+    for (uint32_t i = 0, length = callbacks->Length(); i < length; ++i) {
+        value = callbacks->Get(i);
+        ASSERT(!value.IsEmpty());
+        ASSERT(value->IsFunction());
+        v8::Local<v8::Function> callback = value.As<v8::Function>();
+        call(callback, global, result, mode, isolate);
+    }
+}
+
+void V8PromiseCustom::append(v8::Handle<v8::Object> promise, v8::Handle<v8::Function> fulfillCallback, v8::Handle<v8::Function> rejectCallback, v8::Isolate* isolate)
+{
+    v8::Local<v8::Object> internal = getInternal(promise);
+    ASSERT(!internal.IsEmpty());
+
+    PromiseState state = getState(internal);
+    if (state == Fulfilled) {
+        if (!fulfillCallback.IsEmpty()) {
+            v8::Local<v8::Value> result = internal->GetInternalField(V8PromiseCustom::InternalResultIndex);
+            v8::Local<v8::Object> global = isolate->GetCurrentContext()->Global();
+            call(fulfillCallback, global, result, Asynchronous, isolate);
+        }
+        return;
+    }
+    if (state == Rejected) {
+        if (!rejectCallback.IsEmpty()) {
+            v8::Local<v8::Value> result = internal->GetInternalField(V8PromiseCustom::InternalResultIndex);
+            v8::Local<v8::Object> global = isolate->GetCurrentContext()->Global();
+            call(rejectCallback, global, result, Asynchronous, isolate);
+        }
+        return;
+    }
+
+    ASSERT(state == Pending);
+    if (!fulfillCallback.IsEmpty()) {
+        v8::Local<v8::Value> value = internal->GetInternalField(InternalFulfillCallbackIndex);
+        ASSERT(!value.IsEmpty());
+        ASSERT(value->IsArray());
+        v8::Local<v8::Array> callbacks = value.As<v8::Array>();
+        callbacks->Set(callbacks->Length(), fulfillCallback);
+    }
+    if (!rejectCallback.IsEmpty()) {
+        v8::Local<v8::Value> value = internal->GetInternalField(InternalRejectCallbackIndex);
+        ASSERT(!value.IsEmpty());
+        ASSERT(value->IsArray());
+        v8::Local<v8::Array> callbacks = value.As<v8::Array>();
+        callbacks->Set(callbacks->Length(), rejectCallback);
+    }
+}
+
+v8::Local<v8::Object> V8PromiseCustom::getInternal(v8::Handle<v8::Object> promiseOrPromiseResolver)
+{
+    ASSERT(!promiseOrPromiseResolver.IsEmpty());
+    v8::Local<v8::Value> value = promiseOrPromiseResolver->GetInternalField(v8DOMWrapperObjectIndex);
+    ASSERT(!value.IsEmpty());
+    if (value->IsNull())

[haraken, 2013/06/27 06:55:56]

What if value is undefined?

[yhirano, 2013/06/27 09:29:23]

Null was the special value that indicates the internal object is detached from
the resolver.

I added utility functions for readability and changed the detached mark from
null to undefined.

+        return v8::Local<v8::Object>();
+    ASSERT(value->IsObject());
+    return value.As<v8::Object>();
+}
+
+void V8PromiseCustom::clearInternal(v8::Handle<v8::Object> internal, PromiseState state, v8::Handle<v8::Value> value)
+{
+    ASSERT(!internal.IsEmpty());
+
+    setState(internal, state);
+    internal->SetInternalField(V8PromiseCustom::InternalResultIndex, value);
+    internal->SetInternalField(V8PromiseCustom::InternalFulfillCallbackIndex, v8::Array::New());
+    internal->SetInternalField(V8PromiseCustom::InternalRejectCallbackIndex, v8::Array::New());
+}
+
+V8PromiseCustom::PromiseState V8PromiseCustom::getState(v8::Handle<v8::Object> internal)
+{
+    ASSERT(!internal.IsEmpty());
+    v8::Handle<v8::Value> value = internal->GetInternalField(V8PromiseCustom::InternalStateIndex);
+    ASSERT(!value.IsEmpty());
+    ASSERT(value->IsNumber());
+    double number = value.As<v8::Number>()->Value();

[abarth-chromium, 2013/06/27 06:34:01]

Why not use a v8::Integer ?  We shouldn't have to use doubles here.

[haraken, 2013/06/27 06:55:56]

You can use toInt32() or some utility methods in V8Binding.h.

[yhirano, 2013/06/27 09:29:23]

Done.

+    ASSERT(number == Pending || number == Fulfilled || number == Rejected);
+    return static_cast<PromiseState>(number);
+}
+
+void V8PromiseCustom::setState(v8::Handle<v8::Object> internal, PromiseState state)
+{
+    ASSERT(!internal.IsEmpty());
+    ASSERT(state == Pending || state == Fulfilled || state == Rejected);
+    internal->SetInternalField(V8PromiseCustom::InternalStateIndex, v8::Number::New(state));
+}
+
+void V8PromiseCustom::call(v8::Handle<v8::Function> function, v8::Handle<v8::Object> receiver, v8::Handle<v8::Value> result, SynchronousMode mode, v8::Isolate* isolate)
+{
+    ASSERT(!function.IsEmpty());
+    ASSERT(!receiver.IsEmpty());
+    if (mode == Synchronous) {
+        v8::TryCatch trycatch;

[abarth-chromium, 2013/06/27 06:34:01]

I see.  We catch the exception and ignore it.

[yhirano, 2013/06/27 09:29:23]

I added a comment.

+        V8ScriptRunner::callFunction(function, getScriptExecutionContext(), receiver, 1, &result);

[haraken, 2013/06/27 06:55:56]

Nit: WTF_ARRAY_LENGTH(args).

[yhirano, 2013/06/27 09:29:23]

Done.

+    } else {
+        ASSERT(mode == Asynchronous);
+        postTask(function, receiver, result, isolate);
+    }
+}
+
 } // namespace WebCore