[Fetch API] |(new Response(stream)).body| should return |stream|

third_party/WebKit/Source/modules/fetch/BodyStreamBuffer.cpp

Index: third_party/WebKit/Source/modules/fetch/BodyStreamBuffer.cpp
diff --git a/third_party/WebKit/Source/modules/fetch/BodyStreamBuffer.cpp b/third_party/WebKit/Source/modules/fetch/BodyStreamBuffer.cpp
index 9eec54a24245ef5dd7d7b8f15eb97104eff97f15..0eff04e1895884269705097c52e78357b900418d 100644
--- a/third_party/WebKit/Source/modules/fetch/BodyStreamBuffer.cpp
+++ b/third_party/WebKit/Source/modules/fetch/BodyStreamBuffer.cpp
@@ -13,6 +13,7 @@
 #include "core/streams/ReadableStreamOperations.h"
 #include "modules/fetch/Body.h"
 #include "modules/fetch/DataConsumerHandleUtil.h"
+#include "modules/fetch/ReadableStreamDataConsumerHandle.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/blob/BlobData.h"
 #include "platform/network/EncodedFormData.h"
@@ -84,6 +85,7 @@ BodyStreamBuffer::BodyStreamBuffer(ScriptState* scriptState, PassOwnPtr<FetchDat
     , m_scriptState(scriptState)
     , m_handle(std::move(handle))
     , m_reader(m_handle->obtainReader(this))
+    , m_madeFromReadableStream(false)
 {
     if (RuntimeEnabledFeatures::responseBodyWithV8ExtraStreamEnabled()) {
         ScriptState::Scope scope(scriptState);
@@ -101,6 +103,22 @@ BodyStreamBuffer::BodyStreamBuffer(ScriptState* scriptState, PassOwnPtr<FetchDat
     }
 }
 
+BodyStreamBuffer::BodyStreamBuffer(ScriptState* scriptState, ScriptValue stream)
+    : UnderlyingSourceBase(scriptState)
+    , m_scriptState(scriptState)
+    , m_madeFromReadableStream(true)
+{
+    ScriptState::Scope scope(scriptState);
+    ASSERT(RuntimeEnabledFeatures::responseBodyWithV8ExtraStreamEnabled());
+    ASSERT(ReadableStreamOperations::isReadableStream(scriptState, stream));

[haraken, 2016/05/12 08:22:57]

Use DCHECK.

[yhirano, 2016/05/12 08:28:15]

Done.

+    v8::Local<v8::Value> bodyValue = toV8(this, scriptState);
+    ASSERT(!bodyValue.IsEmpty());
+    ASSERT(bodyValue->IsObject());
+    v8::Local<v8::Object> body = bodyValue.As<v8::Object>();
+
+    V8HiddenValue::setHiddenValue(scriptState, body, V8HiddenValue::internalBodyStream(scriptState->isolate()), stream.v8Value());
+}
+
 ScriptValue BodyStreamBuffer::stream()
 {
     ScriptState::Scope scope(m_scriptState.get());
@@ -121,6 +139,9 @@ PassRefPtr<BlobDataHandle> BodyStreamBuffer::drainAsBlobDataHandle(FetchDataCons
     if (isStreamClosed() || isStreamErrored())
         return nullptr;
 
+    if (m_madeFromReadableStream)
+        return nullptr;
+
     RefPtr<BlobDataHandle> blobDataHandle = m_reader->drainAsBlobDataHandle(policy);
     if (blobDataHandle) {
         closeAndLockAndDisturb();
@@ -136,6 +157,9 @@ PassRefPtr<EncodedFormData> BodyStreamBuffer::drainAsFormData()
     if (isStreamClosed() || isStreamErrored())
         return nullptr;
 
+    if (m_madeFromReadableStream)
+        return nullptr;
+
     RefPtr<EncodedFormData> formData = m_reader->drainAsFormData();
     if (formData) {
         closeAndLockAndDisturb();
@@ -148,6 +172,19 @@ PassOwnPtr<FetchDataConsumerHandle> BodyStreamBuffer::releaseHandle()
 {
     ASSERT(!isStreamLocked());
     ASSERT(!isStreamDisturbed());
+
+    if (m_madeFromReadableStream) {
+        ScriptState::Scope scope(m_scriptState.get());
+        NonThrowableExceptionState exceptionState;
+        ScriptValue reader = ReadableStreamOperations::getReader(m_scriptState.get(), stream(), exceptionState);

[haraken, 2016/05/12 08:22:57]

Is it okay to ignore the exception?

[yhirano, 2016/05/12 08:28:15]

Yes. It throws an exception only when locked, and we have an assertion for that
at L173.

+        // We need to have |reader| alive by some means (as written in
+        // ReadableStreamDataConsumerHandle). |this| BodyStreamBuffer will be
+        // kept alive while the stream is locked and readable, and the stream
+        // has a reference to the reader. Hence we don't need to keep the reader
+        // explicitly.
+        return ReadableStreamDataConsumerHandle::create(m_scriptState.get(), reader);
+    }
+
     // We need to call these before calling closeAndLockAndDisturb.
     const bool isClosed = isStreamClosed();
     const bool isErrored = isStreamErrored();