Introduce KeepAliveWhilePending to ScriptPromiseResolverWithContext.

Source/bindings/v8/ScriptPromiseResolverWithContext.cpp

Index: Source/bindings/v8/ScriptPromiseResolverWithContext.cpp
diff --git a/Source/bindings/v8/ScriptPromiseResolverWithContext.cpp b/Source/bindings/v8/ScriptPromiseResolverWithContext.cpp
index 1a39cac07223f4c777f9d4df80e891041609d0fa..d35f9516ebd48a3969d7d1e9606f377a42990c23 100644
--- a/Source/bindings/v8/ScriptPromiseResolverWithContext.cpp
+++ b/Source/bindings/v8/ScriptPromiseResolverWithContext.cpp
@@ -9,13 +9,28 @@
 
 namespace WebCore {
 
-ScriptPromiseResolverWithContext::ScriptPromiseResolverWithContext(ScriptState* scriptState)
+ScriptPromiseResolverWithContext::ScriptPromiseResolverWithContext(ScriptState* scriptState, Mode mode)
     : ActiveDOMObject(scriptState->executionContext())
     , m_state(Pending)
     , m_scriptState(scriptState)
+    , m_mode(mode)
     , m_timer(this, &ScriptPromiseResolverWithContext::onTimerFired)
     , m_resolver(ScriptPromiseResolver::create(m_scriptState.get()))
 {
+    if (mode == KeepSelfWhilePending) {
+        // Keep |this| while the promise is Pending.
+        // deref() will be called in clear().
+        ref();
+    }
+}
+
+ScriptPromiseResolverWithContext::~ScriptPromiseResolverWithContext()
+{
+    if (m_state != ResolvedOrRejected) {
+        ScriptState::Scope scope(m_scriptState.get());
+        reject(v8::Exception::Error(v8::String::NewFromUtf8(m_scriptState->isolate(),
+            "ScriptPromiseResolverWithContext is destructed without resolve / reject")));
+    }
 }
 
 void ScriptPromiseResolverWithContext::suspend()
@@ -31,6 +46,7 @@ void ScriptPromiseResolverWithContext::resume()
 
 void ScriptPromiseResolverWithContext::stop()
 {
+    ScriptState::Scope scope(m_scriptState.get());
     m_timer.stop();
     clear();
 }
@@ -63,6 +79,9 @@ void ScriptPromiseResolverWithContext::resolveOrRejectImmediately()
 
 void ScriptPromiseResolverWithContext::clear()
 {
+    if (m_state == ResolvedOrRejected)
+        return;
+    RefPtr<ScriptPromiseResolverWithContext> protect(this);

[haraken, 2014/06/16 10:54:04]

Why is this protect needed?

[yhirano, 2014/06/16 11:47:51]

It was needed because I checked m_mode after calling deref.
Now it is not needed because I exchanged two deref blocks.

     ResolutionState state = m_state;
     m_state = ResolvedOrRejected;
     m_resolver.clear();
@@ -71,7 +90,10 @@ void ScriptPromiseResolverWithContext::clear()
         // |ref| was called in |resolveOrReject|.
         deref();

[haraken, 2014/06/16 10:54:04]

Just help me understand: What's the relationship between this deref() and the
deref() you introduced in this CL?

[yhirano, 2014/06/16 11:47:51]

ref() in constructor is for keeping the resolver while the promise is pending.
ref() in resolveOrReject is for keeping the resolver while the resolver is
resolving or rejecting the Promise and the execution context is suspended.

     }
-    // |this| may be deleted here.
+    if (m_mode == KeepSelfWhilePending) {
+        // |ref| was called in the constructor.
+        deref();
+    }
 }
 
 } // namespace WebCore