Revert of Introduce KeepAliveWhilePending to ScriptPromiseResolverWithContext.

Source/modules/crypto/CryptoResultImpl.cpp

Index: Source/modules/crypto/CryptoResultImpl.cpp
diff --git a/Source/modules/crypto/CryptoResultImpl.cpp b/Source/modules/crypto/CryptoResultImpl.cpp
index ef607ea5c01620dbcd48bad2e8a68dec0258304a..84d98137f1bafaf0433024db9b5f1a901de2696f 100644
--- a/Source/modules/crypto/CryptoResultImpl.cpp
+++ b/Source/modules/crypto/CryptoResultImpl.cpp
@@ -47,26 +47,6 @@
 
 namespace WebCore {
 
-namespace {
-
-class WeakResolver : public ScriptPromiseResolverWithContext {
-public:
-    static WeakPtr<ScriptPromiseResolverWithContext> create(ScriptState* scriptState)
-    {
-        RefPtr<WeakResolver> p = adoptRef(new WeakResolver(scriptState));
-        p->suspendIfNeeded();
-        return p->m_weakPtrFactory.createWeakPtr();
-    }
-
-private:
-    explicit WeakResolver(ScriptState* scriptState)
-        : ScriptPromiseResolverWithContext(scriptState, ScriptPromiseResolverWithContext::KeepAliveWhilePending)
-        , m_weakPtrFactory(this) { }
-    WeakPtrFactory<ScriptPromiseResolverWithContext> m_weakPtrFactory;
-};
-
-} // namespace
-
 ExceptionCode webCryptoErrorToExceptionCode(blink::WebCryptoErrorType errorType)
 {
     switch (errorType) {
@@ -95,32 +75,49 @@
     return 0;
 }
 
-CryptoResultImpl::~CryptoResultImpl()
-{
-}
-
-PassRefPtr<CryptoResultImpl> CryptoResultImpl::create(ScriptState* scriptState)
-{
-    return adoptRef(new CryptoResultImpl(scriptState));
-}
-
-void CryptoResultImpl::completeWithError(blink::WebCryptoErrorType errorType, const blink::WebString& errorDetails)
-{
-    if (m_resolver)
-        m_resolver->reject(DOMException::create(webCryptoErrorToExceptionCode(errorType), errorDetails));
-}
-
-void CryptoResultImpl::completeWithBuffer(const blink::WebArrayBuffer& buffer)
-{
-    if (m_resolver)
-        m_resolver->resolve(PassRefPtr<ArrayBuffer>(buffer));
-}
-
-void CryptoResultImpl::completeWithJson(const char* utf8Data, unsigned length)
-{
-    if (m_resolver) {
-        ScriptPromiseResolverWithContext* resolver = m_resolver.get();
-        ScriptState* scriptState = resolver->scriptState();
+// The PromiseState class contains all the state which is tied to an
+// ExecutionContext. Whereas CryptoResultImpl can be deleted from any thread,
+// PromiseState is not thread safe and must only be accessed and deleted from
+// the blink thread.
+//
+// This is achieved by making CryptoResultImpl hold a WeakPtr to the PromiseState.
+// The PromiseState deletes itself after being notified of completion.
+// Additionally the PromiseState is deleted when the ExecutionContext is
+// destroyed (necessary to avoid leaks when dealing with WebWorker threads,
+// which may die before the operation is completed).
+class CryptoResultImpl::PromiseState FINAL {
+public:
+    static WeakPtr<PromiseState> create(ScriptState* scriptState)
+    {
+        PromiseState* promiseState = new PromiseState(scriptState);
+        return promiseState->m_weakFactory.createWeakPtr();
+    }
+
+    void contextDestroyed()
+    {
+        delete this;
+    }
+
+    ScriptPromise promise()
+    {
+        return m_promiseResolver->promise();
+    }
+
+    void completeWithError(blink::WebCryptoErrorType errorType, const blink::WebString& errorDetails)
+    {
+        m_promiseResolver->reject(DOMException::create(webCryptoErrorToExceptionCode(errorType), errorDetails));
+        delete this;
+    }
+
+    void completeWithBuffer(const blink::WebArrayBuffer& buffer)
+    {
+        m_promiseResolver->resolve(PassRefPtr<ArrayBuffer>(buffer));
+        delete this;
+    }
+
+    void completeWithJson(const char* utf8Data, unsigned length)
+    {
+        ScriptState* scriptState = m_promiseResolver->scriptState();
         ScriptState::Scope scope(scriptState);
 
         v8::Handle<v8::String> jsonString = v8::String::NewFromUtf8(scriptState->isolate(), utf8Data, v8::String::kInternalizedString, length);
@@ -129,39 +126,122 @@
         v8::Handle<v8::Value> jsonDictionary = v8::JSON::Parse(jsonString);
         if (exceptionCatcher.HasCaught() || jsonDictionary.IsEmpty()) {
             ASSERT_NOT_REACHED();
-            resolver->reject(DOMException::create(OperationError, "Failed inflating JWK JSON to object"));
+            m_promiseResolver->reject(DOMException::create(OperationError, "Failed inflating JWK JSON to object"));
         } else {
-            resolver->resolve(jsonDictionary);
-        }
-    }
+            m_promiseResolver->resolve(jsonDictionary);
+        }
+        delete this;
+    }
+
+    void completeWithBoolean(bool b)
+    {
+        m_promiseResolver->resolve(b);
+        delete this;
+    }
+
+    void completeWithKey(const blink::WebCryptoKey& key)
+    {
+        m_promiseResolver->resolve(Key::create(key));
+        delete this;
+    }
+
+    void completeWithKeyPair(const blink::WebCryptoKey& publicKey, const blink::WebCryptoKey& privateKey)
+    {
+        m_promiseResolver->resolve(KeyPair::create(publicKey, privateKey));
+        delete this;
+    }
+
+private:
+    // This subclass of ScriptPromiseResolverWithContext is to be notified
+    // when the context was destroyed.
+    class PromiseResolver FINAL : public ScriptPromiseResolverWithContext {
+    public:
+        static PassRefPtr<PromiseResolver> create(ScriptState* scriptState, PromiseState* promiseState)
+        {
+            RefPtr<PromiseResolver> resolver = adoptRef(new PromiseResolver(scriptState, promiseState));
+            resolver->suspendIfNeeded();
+            return resolver.release();
+        }
+
+        virtual void contextDestroyed() OVERRIDE
+        {
+            ScriptPromiseResolverWithContext::contextDestroyed();
+            m_promiseState->contextDestroyed();
+        }
+
+    private:
+        explicit PromiseResolver(ScriptState* scriptState, PromiseState* promiseState)
+            : ScriptPromiseResolverWithContext(scriptState)
+            , m_promiseState(promiseState)
+        {
+        }
+
+        PromiseState* m_promiseState;
+    };
+
+    explicit PromiseState(ScriptState* scriptState)
+        : m_weakFactory(this)
+        , m_promiseResolver(PromiseResolver::create(scriptState, this))
+    {
+    }
+
+    WeakPtrFactory<PromiseState> m_weakFactory;
+    RefPtr<PromiseResolver> m_promiseResolver;
+};
+
+CryptoResultImpl::~CryptoResultImpl()
+{
+}
+
+PassRefPtr<CryptoResultImpl> CryptoResultImpl::create(ScriptState* scriptState)
+{
+    return adoptRef(new CryptoResultImpl(scriptState));
+}
+
+void CryptoResultImpl::completeWithError(blink::WebCryptoErrorType errorType, const blink::WebString& errorDetails)
+{
+    if (m_promiseState)
+        m_promiseState->completeWithError(errorType, errorDetails);
+}
+
+void CryptoResultImpl::completeWithBuffer(const blink::WebArrayBuffer& buffer)
+{
+    if (m_promiseState)
+        m_promiseState->completeWithBuffer(buffer);
+}
+
+void CryptoResultImpl::completeWithJson(const char* utf8Data, unsigned length)
+{
+    if (m_promiseState)
+        m_promiseState->completeWithJson(utf8Data, length);
 }
 
 void CryptoResultImpl::completeWithBoolean(bool b)
 {
-    if (m_resolver)
-        m_resolver->resolve(b);
+    if (m_promiseState)
+        m_promiseState->completeWithBoolean(b);
 }
 
 void CryptoResultImpl::completeWithKey(const blink::WebCryptoKey& key)
 {
-    if (m_resolver)
-        m_resolver->resolve(Key::create(key));
+    if (m_promiseState)
+        m_promiseState->completeWithKey(key);
 }
 
 void CryptoResultImpl::completeWithKeyPair(const blink::WebCryptoKey& publicKey, const blink::WebCryptoKey& privateKey)
 {
-    if (m_resolver)
-        m_resolver->resolve(KeyPair::create(publicKey, privateKey));
+    if (m_promiseState)
+        m_promiseState->completeWithKeyPair(publicKey, privateKey);
 }
 
 CryptoResultImpl::CryptoResultImpl(ScriptState* scriptState)
-    : m_resolver(WeakResolver::create(scriptState))
+    : m_promiseState(PromiseState::create(scriptState))
 {
 }
 
 ScriptPromise CryptoResultImpl::promise()
 {
-    return m_resolver->promise();
+    return m_promiseState->promise();
 }
 
 } // namespace WebCore