[Fetch API] Remove DrainingBuffer.

Source/modules/fetch/Body.cpp

Index: Source/modules/fetch/Body.cpp
diff --git a/Source/modules/fetch/Body.cpp b/Source/modules/fetch/Body.cpp
index 902ed48e0465637cdb9ae9a48e8bff993139f3a0..18b88f1041d43cf147f43194e3c372ebf20d94ce 100644
--- a/Source/modules/fetch/Body.cpp
+++ b/Source/modules/fetch/Body.cpp
@@ -15,194 +15,94 @@
 #include "core/dom/ExceptionCode.h"
 #include "core/fileapi/Blob.h"
 #include "core/frame/UseCounter.h"
-#include "core/streams/ReadableByteStream.h"
-#include "core/streams/ReadableByteStreamReader.h"
-#include "core/streams/UnderlyingSource.h"
 #include "modules/fetch/BodyStreamBuffer.h"
-#include "modules/fetch/DataConsumerHandleUtil.h"
-#include "modules/fetch/FetchBlobDataConsumerHandle.h"
+#include "modules/fetch/FetchDataLoader.h"
+#include "wtf/PassRefPtr.h"
+#include "wtf/RefPtr.h"
 
 namespace blink {
 
-class Body::ReadableStreamSource : public GarbageCollectedFinalized<Body::ReadableStreamSource>, public UnderlyingSource, public WebDataConsumerHandle::Client, public BodyStreamBuffer::DrainingStreamNotificationClient {
-    USING_GARBAGE_COLLECTED_MIXIN(ReadableStreamSource);
+namespace {
+
+class BodyConsumerBase : public GarbageCollectedFinalized<BodyConsumerBase>, public FetchDataLoader::Client {
+    WTF_MAKE_NONCOPYABLE(BodyConsumerBase);
+    USING_GARBAGE_COLLECTED_MIXIN(BodyConsumerBase);
 public:
-    ReadableStreamSource(ExecutionContext* executionContext, BodyStreamBuffer* buffer)
-        : m_bodyStreamBuffer(buffer)
-        , m_streamNeedsMore(false)
-#if ENABLE(ASSERT)
-        , m_drained(false)
-        , m_isCloseCalled(false)
-        , m_isErrorCalled(false)
-#endif
+    explicit BodyConsumerBase(PassRefPtrWillBeRawPtr<ScriptPromiseResolver> resolver) : m_resolver(resolver) {}
+    PassRefPtrWillBeRawPtr<ScriptPromiseResolver> resolver() { return m_resolver; }
+    void didFetchDataLoadFailed() override
     {
-        if (m_bodyStreamBuffer)
-            obtainReader();
+        ScriptState::Scope scope(resolver()->scriptState());
+        m_resolver->reject(V8ThrowException::createTypeError(resolver()->scriptState()->isolate(), "Failed to fetch"));
     }
 
-    ~ReadableStreamSource() override { }
-
-    void startStream(ReadableByteStream* stream)
-    {
-        m_stream = stream;
-        stream->didSourceStart();
-        if (!m_bodyStreamBuffer)
-            close();
-    }
-    // Creates a new BodyStreamBuffer to drain the data.
-    PassOwnPtr<DrainingBodyStreamBuffer> createDrainingStream()
+    DEFINE_INLINE_TRACE()
     {
-        if (!m_bodyStreamBuffer)
-            return nullptr;
-
-#if ENABLE(ASSERT)
-        ASSERT(!m_drained);
-        m_drained = true;
-        ASSERT(!(m_stream->stateInternal() == ReadableByteStream::Closed && !m_isCloseCalled));
-        ASSERT(!(m_stream->stateInternal() == ReadableByteStream::Errored && !m_isErrorCalled));
-#endif
-
-        m_reader.clear();
-        return DrainingBodyStreamBuffer::create(m_bodyStreamBuffer, this);
+        visitor->trace(m_resolver);
+        FetchDataLoader::Client::trace(visitor);
     }
 
-    DEFINE_INLINE_VIRTUAL_TRACE()
-    {
-        visitor->trace(m_bodyStreamBuffer);
-        visitor->trace(m_stream);
-        UnderlyingSource::trace(visitor);
-        DrainingStreamNotificationClient::trace(visitor);
-    }
+private:
+    RefPtrWillBeMember<ScriptPromiseResolver> m_resolver;
+};
 
-    void close()
-    {
-        m_reader.clear();
-        m_stream->close();
-        if (m_bodyStreamBuffer)
-            m_bodyStreamBuffer = BodyStreamBuffer::createEmpty();
-#if ENABLE(ASSERT)
-        m_isCloseCalled = true;
-#endif
-    }
+class BodyBlobConsumer final : public BodyConsumerBase {
+    WTF_MAKE_NONCOPYABLE(BodyBlobConsumer);
+public:
+    explicit BodyBlobConsumer(PassRefPtrWillBeRawPtr<ScriptPromiseResolver> resolver) : BodyConsumerBase(resolver) {}
 
-    void error()
+    void didFetchDataLoadedBlobHandle(PassRefPtr<BlobDataHandle> blobDataHandle) override
     {
-        m_reader.clear();
-        m_stream->error(DOMException::create(NetworkError, "network error"));
-        if (m_bodyStreamBuffer)
-            m_bodyStreamBuffer = BodyStreamBuffer::create(createFetchDataConsumerHandleFromWebHandle(createUnexpectedErrorDataConsumerHandle()));
-#if ENABLE(ASSERT)
-        m_isErrorCalled = true;
-#endif
+        resolver()->resolve(Blob::create(blobDataHandle));
     }
+};
 
-private:
-    void obtainReader()
-    {
-        m_reader = m_bodyStreamBuffer->handle()->obtainReader(this);
-    }
+class BodyArrayBufferConsumer final : public BodyConsumerBase {
+    WTF_MAKE_NONCOPYABLE(BodyArrayBufferConsumer);
+public:
+    explicit BodyArrayBufferConsumer(PassRefPtrWillBeRawPtr<ScriptPromiseResolver> resolver) : BodyConsumerBase(resolver) {}
 
-    void didFetchDataLoadFinishedFromDrainingStream()
+    void didFetchDataLoadedArrayBuffer(PassRefPtr<DOMArrayBuffer> arrayBuffer) override
     {
-        ASSERT(m_bodyStreamBuffer);
-        ASSERT(m_drained);
-
-#if ENABLE(ASSERT)
-        m_drained = false;
-#endif
-        obtainReader();
-        // We have to call didGetReadable() now to call close()/error() if
-        // necessary.
-        // didGetReadable() would be called asynchronously, but it is too late.
-        didGetReadable();
+        resolver()->resolve(arrayBuffer);
     }
+};
 
-    void didGetReadable() override
-    {
-        if (!m_streamNeedsMore) {
-            // Perform zero-length read to call close()/error() early.
-            size_t readSize;
-            WebDataConsumerHandle::Result result = m_reader->read(nullptr, 0, WebDataConsumerHandle::FlagNone, &readSize);
-            switch (result) {
-            case WebDataConsumerHandle::Ok:
-            case WebDataConsumerHandle::ShouldWait:
-                return;
-            case WebDataConsumerHandle::Done:
-                close();
-                return;
-            case WebDataConsumerHandle::Busy:
-            case WebDataConsumerHandle::ResourceExhausted:
-            case WebDataConsumerHandle::UnexpectedError:
-                error();
-                return;
-            }
-        }
-
-        processData();
-    }
+class BodyTextConsumer final : public BodyConsumerBase {
+    WTF_MAKE_NONCOPYABLE(BodyTextConsumer);
+public:
+    explicit BodyTextConsumer(PassRefPtrWillBeRawPtr<ScriptPromiseResolver> resolver) : BodyConsumerBase(resolver) {}
 
-    // UnderlyingSource functions.
-    void pullSource() override
+    void didFetchDataLoadedString(const String& string) override
     {
-        ASSERT(!m_streamNeedsMore);
-        m_streamNeedsMore = true;
-
-        ASSERT(!m_drained);
-
-        processData();
+        resolver()->resolve(string);
     }
+};
 
-    ScriptPromise cancelSource(ScriptState* scriptState, ScriptValue reason) override
-    {
-        close();
-        return ScriptPromise::cast(scriptState, v8::Undefined(scriptState->isolate()));
-    }
+class BodyJsonConsumer final : public BodyConsumerBase {
+    WTF_MAKE_NONCOPYABLE(BodyJsonConsumer);
+public:
+    explicit BodyJsonConsumer(PassRefPtrWillBeRawPtr<ScriptPromiseResolver> resolver) : BodyConsumerBase(resolver) {}
 
-    // Reads data and writes the data to |m_stream|, as long as data are
-    // available and the stream has pending reads.
-    void processData()
+    void didFetchDataLoadedString(const String& string) override
     {
-        ASSERT(m_reader);
-        while (m_streamNeedsMore) {
-            const void* buffer;
-            size_t available;
-            WebDataConsumerHandle::Result result = m_reader->beginRead(&buffer, WebDataConsumerHandle::FlagNone, &available);
-            switch (result) {
-            case WebDataConsumerHandle::Ok:
-                m_streamNeedsMore = m_stream->enqueue(DOMUint8Array::create(static_cast<const unsigned char*>(buffer), available));
-                m_reader->endRead(available);
-                break;
-
-            case WebDataConsumerHandle::Done:
-                close();
-                return;
-
-            case WebDataConsumerHandle::ShouldWait:
-                return;
-
-            case WebDataConsumerHandle::Busy:
-            case WebDataConsumerHandle::ResourceExhausted:
-            case WebDataConsumerHandle::UnexpectedError:
-                error();
-                return;
-            }
-        }
+        if (!resolver()->executionContext() || resolver()->executionContext()->activeDOMObjectsAreStopped())
+            return;
+        ScriptState::Scope scope(resolver()->scriptState());
+        v8::Isolate* isolate = resolver()->scriptState()->isolate();
+        v8::Local<v8::String> inputString = v8String(isolate, string);
+        v8::TryCatch trycatch;
+        v8::Local<v8::Value> parsed;
+        if (v8Call(v8::JSON::Parse(isolate, inputString), parsed, trycatch))
+            resolver()->resolve(parsed);
+        else
+            resolver()->reject(trycatch.Exception());
     }
-
-    // Source of data.
-    Member<BodyStreamBuffer> m_bodyStreamBuffer;
-    OwnPtr<FetchDataConsumerHandle::Reader> m_reader;
-
-    Member<ReadableByteStream> m_stream;
-    bool m_streamNeedsMore;
-#if ENABLE(ASSERT)
-    bool m_drained;
-    bool m_isCloseCalled;
-    bool m_isErrorCalled;
-#endif
 };
 
-ScriptPromise Body::readAsync(ScriptState* scriptState, ResponseType type)
+} // namespace
+
+ScriptPromise Body::arrayBuffer(ScriptState* scriptState)
 {
     if (bodyUsed())
         return ScriptPromise::reject(scriptState, V8ThrowException::createTypeError(scriptState->isolate(), "Already read"));
@@ -213,256 +113,82 @@ ScriptPromise Body::readAsync(ScriptState* scriptState, ResponseType type)
     // first check the ExecutionContext and return immediately if it's already
     // gone (which means that the V8::TerminateExecution() signal has been sent
     // to this worker thread).
-    ExecutionContext* executionContext = scriptState->executionContext();
-    if (!executionContext)
+    if (!scriptState->executionContext())
         return ScriptPromise();
 
-    lockBody();
-    m_responseType = type;
-
-    ASSERT(!m_resolver);
-    m_resolver = ScriptPromiseResolver::create(scriptState);
-    ScriptPromise promise = m_resolver->promise();
-
-    if (m_stream->stateInternal() == ReadableStream::Closed) {
-        resolveWithEmptyDataSynchronously();
-    } else if (m_stream->stateInternal() == ReadableStream::Errored) {
-        m_resolver->reject(m_stream->storedException());
-        m_resolver.clear();
-    } else {
-        readAsyncFromDrainingBodyStreamBuffer(createDrainingStream(), mimeType());
-    }
+    RefPtrWillBeRawPtr<ScriptPromiseResolver> resolver = ScriptPromiseResolver::create(scriptState);
+    ScriptPromise promise = resolver->promise();
+    bodyBuffer()->startLoading(scriptState->executionContext(), FetchDataLoader::createLoaderAsArrayBuffer(), new BodyArrayBufferConsumer(resolver));
     return promise;
 }
 
-void Body::resolveWithEmptyDataSynchronously()
-{
-    // We resolve the resolver manually in order not to use member
-    // variables.
-    switch (m_responseType) {
-    case ResponseAsArrayBuffer:
-        m_resolver->resolve(DOMArrayBuffer::create(nullptr, 0));
-        break;
-    case ResponseAsBlob: {
-        OwnPtr<BlobData> blobData = BlobData::create();
-        blobData->setContentType(mimeType());
-        m_resolver->resolve(Blob::create(BlobDataHandle::create(blobData.release(), 0)));
-        break;
-    }
-    case ResponseAsText:
-        m_resolver->resolve(String());
-        break;
-    case ResponseAsFormData:
-        // TODO(yhirano): Implement this.
-        ASSERT_NOT_REACHED();
-        break;
-    case ResponseAsJSON: {
-        ScriptState::Scope scope(m_resolver->scriptState());
-        m_resolver->reject(V8ThrowException::createSyntaxError(m_resolver->scriptState()->isolate(), "Unexpected end of input"));
-        break;
-    }
-    case ResponseUnknown:
-        ASSERT_NOT_REACHED();
-        break;
-    }
-    m_resolver.clear();
-}
-
-void Body::readAsyncFromDrainingBodyStreamBuffer(PassOwnPtr<DrainingBodyStreamBuffer> buffer, const String& mimeType)
+ScriptPromise Body::blob(ScriptState* scriptState)
 {
-    if (!buffer) {
-        resolveWithEmptyDataSynchronously();
-        m_streamSource->close();
-        return;
-    }
-
-    FetchDataLoader* fetchDataLoader = nullptr;
-
-    switch (m_responseType) {
-    case ResponseAsArrayBuffer:
-        fetchDataLoader = FetchDataLoader::createLoaderAsArrayBuffer();
-        break;
-
-    case ResponseAsJSON:
-    case ResponseAsText:
-        fetchDataLoader = FetchDataLoader::createLoaderAsString();
-        break;
-
-    case ResponseAsBlob:
-        fetchDataLoader = FetchDataLoader::createLoaderAsBlobHandle(mimeType);
-        break;
+    if (bodyUsed())
+        return ScriptPromise::reject(scriptState, V8ThrowException::createTypeError(scriptState->isolate(), "Already read"));
 
-    case ResponseAsFormData:
-        // FIXME: Implement this.
-        ASSERT_NOT_REACHED();
-        return;
+    // See above comment.
+    if (!scriptState->executionContext())
+        return ScriptPromise();
 
-    default:
-        ASSERT_NOT_REACHED();
-        return;
-    }
+    RefPtrWillBeRawPtr<ScriptPromiseResolver> resolver = ScriptPromiseResolver::create(scriptState);
+    ScriptPromise promise = resolver->promise();
+    bodyBuffer()->startLoading(scriptState->executionContext(), FetchDataLoader::createLoaderAsBlobHandle(mimeType()), new BodyBlobConsumer(resolver));
+    return promise;
 
-    buffer->startLoading(fetchDataLoader, this);
 }
 
-ScriptPromise Body::arrayBuffer(ScriptState* scriptState)
-{
-    return readAsync(scriptState, ResponseAsArrayBuffer);
-}
-
-ScriptPromise Body::blob(ScriptState* scriptState)
+ScriptPromise Body::json(ScriptState* scriptState)
 {
-    return readAsync(scriptState, ResponseAsBlob);
-}
+    if (bodyUsed())
+        return ScriptPromise::reject(scriptState, V8ThrowException::createTypeError(scriptState->isolate(), "Already read"));
 
-ScriptPromise Body::formData(ScriptState* scriptState)
-{
-    return readAsync(scriptState, ResponseAsFormData);
-}
+    // See above comment.
+    if (!scriptState->executionContext())
+        return ScriptPromise();
 
-ScriptPromise Body::json(ScriptState* scriptState)
-{
-    return readAsync(scriptState, ResponseAsJSON);
+    RefPtrWillBeRawPtr<ScriptPromiseResolver> resolver = ScriptPromiseResolver::create(scriptState);
+    ScriptPromise promise = resolver->promise();
+    bodyBuffer()->startLoading(scriptState->executionContext(), FetchDataLoader::createLoaderAsString(), new BodyJsonConsumer(resolver));
+    return promise;
 }
 
 ScriptPromise Body::text(ScriptState* scriptState)
 {
-    return readAsync(scriptState, ResponseAsText);
-}
-
-ReadableByteStream* Body::body()
-{
-    UseCounter::count(executionContext(), UseCounter::FetchBodyStream);
-    return m_stream;
-}
+    if (bodyUsed())
+        return ScriptPromise::reject(scriptState, V8ThrowException::createTypeError(scriptState->isolate(), "Already read"));
 
-bool Body::bodyUsed() const
-{
-    return m_bodyUsed || m_stream->isLocked();
-}
+    // See above comment.
+    if (!scriptState->executionContext())
+        return ScriptPromise();
 
-void Body::lockBody(LockBodyOption option)
-{
-    ASSERT(!bodyUsed());
-    if (option == PassBody)
-        m_bodyUsed = true;
-    ASSERT(!m_stream->isLocked());
-    TrackExceptionState exceptionState;
-    m_stream->getBytesReader(executionContext(), exceptionState);
-    ASSERT(!exceptionState.hadException());
+    RefPtrWillBeRawPtr<ScriptPromiseResolver> resolver = ScriptPromiseResolver::create(scriptState);
+    ScriptPromise promise = resolver->promise();
+    bodyBuffer()->startLoading(scriptState->executionContext(), FetchDataLoader::createLoaderAsString(), new BodyTextConsumer(resolver));
+    return promise;
 }
 
-void Body::setBody(BodyStreamBuffer* buffer)
+ReadableByteStream* Body::body()
 {
-    m_streamSource = new ReadableStreamSource(executionContext(), buffer);
-    m_stream = new ReadableByteStream(m_streamSource, new ReadableByteStream::StrictStrategy);
-    m_streamSource->startStream(m_stream);
+    UseCounter::count(executionContext(), UseCounter::FetchBodyStream);
+    return bodyBuffer()->stream();
 }
 
-PassOwnPtr<DrainingBodyStreamBuffer> Body::createDrainingStream()
+bool Body::bodyUsed()
 {
-    return m_streamSource->createDrainingStream();
+    return m_bodyPassed || body()->isLocked();
 }
 
 bool Body::hasPendingActivity() const
 {
     if (executionContext()->activeDOMObjectsAreStopped())
         return false;
-    if (m_resolver)
-        return true;
-    if (m_stream->isLocked())
-        return true;
-    return false;
-}
-
-DEFINE_TRACE(Body)
-{
-    visitor->trace(m_resolver);
-    visitor->trace(m_stream);
-    visitor->trace(m_streamSource);
-    ActiveDOMObject::trace(visitor);
-    FetchDataLoader::Client::trace(visitor);
-}
-
-Body::Body(ExecutionContext* context)
-    : ActiveDOMObject(context)
-    , m_bodyUsed(false)
-    , m_responseType(ResponseType::ResponseUnknown)
-    , m_streamSource(new ReadableStreamSource(context, nullptr))
-    , m_stream(new ReadableByteStream(m_streamSource, new ReadableByteStream::StrictStrategy))
-{
-    m_streamSource->startStream(m_stream);
-}
-
-void Body::resolveJSON(const String& string)
-{
-    ASSERT(m_responseType == ResponseAsJSON);
-    ScriptState::Scope scope(m_resolver->scriptState());
-    v8::Isolate* isolate = m_resolver->scriptState()->isolate();
-    v8::Local<v8::String> inputString = v8String(isolate, string);
-    v8::TryCatch trycatch;
-    v8::Local<v8::Value> parsed;
-    if (v8Call(v8::JSON::Parse(isolate, inputString), parsed, trycatch))
-        m_resolver->resolve(parsed);
-    else
-        m_resolver->reject(trycatch.Exception());
-}
-
-// FetchDataLoader::Client functions.
-void Body::didFetchDataLoadFailed()
-{
-    if (!executionContext() || executionContext()->activeDOMObjectsAreStopped())
-        return;
-
-    if (m_resolver) {
-        if (!m_resolver->executionContext() || m_resolver->executionContext()->activeDOMObjectsAreStopped()) {
-            m_resolver.clear();
-            return;
-        }
-        ScriptState* state = m_resolver->scriptState();
-        ScriptState::Scope scope(state);
-        m_resolver->reject(V8ThrowException::createTypeError(state->isolate(), "Failed to fetch"));
-        m_resolver.clear();
-    }
-}
-
-void Body::didFetchDataLoadedBlobHandle(PassRefPtr<BlobDataHandle> blobDataHandle)
-{
-    if (!executionContext() || executionContext()->activeDOMObjectsAreStopped())
-        return;
-
-    ASSERT(m_responseType == ResponseAsBlob);
-    m_resolver->resolve(Blob::create(blobDataHandle));
-    m_resolver.clear();
+    return bodyBuffer()->hasPendingActivity();
 }
 
-void Body::didFetchDataLoadedArrayBuffer(PassRefPtr<DOMArrayBuffer> arrayBuffer)
+Body::Body(ExecutionContext* context) : ActiveDOMObject(context), m_bodyPassed(false)
 {
-    if (!executionContext() || executionContext()->activeDOMObjectsAreStopped())
-        return;
-
-    ASSERT(m_responseType == ResponseAsArrayBuffer);
-    m_resolver->resolve(arrayBuffer);
-    m_resolver.clear();
-}
-
-void Body::didFetchDataLoadedString(const String& str)
-{
-    if (!executionContext() || executionContext()->activeDOMObjectsAreStopped())
-        return;
-
-    switch (m_responseType) {
-    case ResponseAsJSON:
-        resolveJSON(str);
-        break;
-    case ResponseAsText:
-        m_resolver->resolve(str);
-        break;
-    default:
-        ASSERT_NOT_REACHED();
-    }
-
-    m_resolver.clear();
+    suspendIfNeeded();
 }
 
 } // namespace blink