Change BodyStreamBuffer to be FetchDataConsumerHandle-based and enable backpressure in Fetch API

Source/modules/fetch/Request.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "modules/fetch/Request.h"
 
 #include "bindings/core/v8/Dictionary.h"
 #include "core/dom/Document.h"
 #include "core/dom/ExecutionContext.h"
 #include "core/fetch/FetchUtils.h"
 #include "core/fetch/ResourceLoaderOptions.h"
 #include "core/loader/ThreadableLoader.h"
+#include "modules/fetch/BodyStreamBuffer.h"
+#include "modules/fetch/FetchBlobDataConsumerHandle.h"
 #include "modules/fetch/FetchManager.h"
 #include "modules/fetch/RequestInit.h"
 #include "platform/network/HTTPParsers.h"
 #include "platform/network/ResourceRequest.h"
 #include "platform/weborigin/Referrer.h"
 #include "public/platform/WebServiceWorkerRequest.h"
 #include "public/platform/WebURLRequest.h"
 
 namespace blink {
 
@@ skipping 16 matching lines @@
     request->setMode(original->mode());
     request->setCredentials(original->credentials());
     // FIXME: Set cache mode.
     // TODO(yhirano): Set redirect mode.
     return request;
 }
 
 Request* Request::createRequestWithRequestOrString(ScriptState* scriptState, Request* inputRequest, const String& inputString, const RequestInit& init, ExceptionState& exceptionState)
 {
     // "1. Let |temporaryBody| be null."
-    RefPtr<BlobDataHandle> temporaryBody;
+    OwnPtr<DrainingBodyStreamBuffer> temporaryBody = nullptr;
 
     if (inputRequest) {
         // We check bodyUsed even when the body is null in spite of the
         // spec. See https://github.com/whatwg/fetch/issues/61 for details.
         if (inputRequest->bodyUsed()) {
             exceptionState.throwTypeError("Cannot construct a Request with a Request object that has already been used.");
             return nullptr;
         }
     }
 
     // "2. If |input| is a Request object and |input|'s body is non-null, run
     // these substeps:"
     if (inputRequest && inputRequest->hasBody()) {
         // "1. If |input|'s used flag is set, throw a TypeError."
         // "2. Set |temporaryBody| to |input|'s body."
         if (inputRequest->bodyUsed()) {
             exceptionState.throwTypeError("Cannot construct a Request with a Request object that has already been used.");
             return nullptr;
         }
-        if (inputRequest->isBodyConsumed()) {
-            // Currently the only methods that can consume body data without
-            // setting 'body passed' flag consume entire body (e.g. text()).
-            // Thus we can set an empty blob to the new request instead of
-            // creating a draining stream.
-            // TODO(yhirano): Fix this once Request.body is introduced.
-            OwnPtr<BlobData> blobData = BlobData::create();
-            blobData->setContentType(inputRequest->blobDataHandle()->type());
-            temporaryBody = BlobDataHandle::create(blobData.release(), 0);
-        } else {
-            temporaryBody = inputRequest->m_request->blobDataHandle();
-        }
+        temporaryBody = inputRequest->createDrainingStream();

[yhirano, 2015/07/03 04:42:28]

The spec intends to not mutate |inputRequest|'s body until it is actually used
(e.g. the constructor throws, |body| property is specified, etc). I think
createDrainingStream has side-effect, right?
If not, please add comments.

[hiroshige, 2015/07/05 07:30:25]

Yes.
I modified the code to remove the side effects on |inputRequest|'s body.

     }
 
     // "3. Let |request| be |input|'s request, if |input| is a Request object,
     // and a new request otherwise."
     // "4. Set |request| to a new request whose url is |request|'s url, method
     // is |request|'s method, header list is a copy of |request|'s header list,
     // unsafe request flag is set, client is entry settings object, origin is
     // entry settings object's origin, force Origin header flag is set,
     // same-origin data URL flag is set, context is the empty string, mode is
     // |request|'s mode, credentials mode is |request|'s credentials mode,
@@ skipping 136 matching lines @@
 
     // "28. If |init|'s body member is present, run these substeps:"
     if (init.bodyBlobHandle) {
         // "1. Let |stream| and |Content-Type| be the result of extracting
         //  |init|'s body member."
         // "2. Set |temporaryBody| to |stream|.
         // "3. If |Content-Type| is non-null and |r|'s request's header list
         //  contains no header named `Content-Type`, append
         //  `Content-Type`/|Content-Type| to |r|'s Headers object. Rethrow any
         //  exception."
-        temporaryBody = init.bodyBlobHandle;
+        temporaryBody = DrainingBodyStreamBuffer::create(BodyStreamBuffer::create(FetchBlobDataConsumerHandle::create(scriptState->executionContext(), init.bodyBlobHandle)), nullptr);
         if (!init.bodyBlobHandle->type().isEmpty() && !r->headers()->has("Content-Type", exceptionState)) {
             r->headers()->append("Content-Type", init.bodyBlobHandle->type(), exceptionState);
         }
         if (exceptionState.hadException())
             return nullptr;
     }
 
     // "29. Set |r|'s body to |temporaryBody|.
-    r->setBodyBlobHandle(temporaryBody.release());
+    if (temporaryBody)
+        r->setBuffer(temporaryBody->leak());
 
     // "30. Set |r|'s MIME type to the result of extracting a MIME type from
     // |r|'s request's header list."
     r->m_request->setMIMEType(r->m_request->headerList()->extractMIMEType());
 
     // "31. If |input| is a Request object and |input|'s body is non-null, run
     // these substeps:"
     // We set bodyUsed even when the body is null in spite of the
     // spec. See https://github.com/whatwg/fetch/issues/61 for details.
     if (inputRequest) {
         // "1. Set |input|'s body to null."
-        inputRequest->setBodyBlobHandle(nullptr);
+        inputRequest->setBuffer(nullptr);
         // "2. Set |input|'s used flag."
         inputRequest->lockBody(PassBody);
     }
 
     // "32. Return |r|."
     return r;
 }
 
 Request* Request::create(ScriptState* scriptState, const RequestInfo& input, const Dictionary& init, ExceptionState& exceptionState)
 {
@@ skipping 29 matching lines @@
     r->suspendIfNeeded();
     return r;
 }
 
 Request::Request(ExecutionContext* context, FetchRequestData* request)
     : Body(context)
     , m_request(request)
     , m_headers(Headers::create(m_request->headerList()))
 {
     m_headers->setGuard(Headers::RequestGuard);
+
+    refreshBody();
 }
 
 Request::Request(ExecutionContext* context, FetchRequestData* request, Headers* headers)
-    : Body(context) , m_request(request) , m_headers(headers) { }
+    : Body(context) , m_request(request) , m_headers(headers)
+{
+    refreshBody();
+}
 
 Request* Request::create(ExecutionContext* context, const WebServiceWorkerRequest& webRequest)
 {
     Request* r = new Request(context, webRequest);
     r->suspendIfNeeded();
     return r;
 }
 
 Request::Request(ExecutionContext* context, const WebServiceWorkerRequest& webRequest)
     : Body(context)
-    , m_request(FetchRequestData::create(webRequest))
+    , m_request(FetchRequestData::create(context, webRequest))
     , m_headers(Headers::create(m_request->headerList()))
 {
     m_headers->setGuard(Headers::RequestGuard);
+
+    refreshBody();
 }
 
 String Request::method() const
 {
     // "The method attribute's getter must return request's method."
     return m_request->method();
 }
 
 KURL Request::url() const
 {
@@ skipping 121 matching lines @@
         return "omit";
     case WebURLRequest::FetchCredentialsModeSameOrigin:
         return "same-origin";
     case WebURLRequest::FetchCredentialsModeInclude:
         return "include";
     }
     ASSERT_NOT_REACHED();
     return "";
 }
 
-Request* Request::clone(ExceptionState& exceptionState) const
+Request* Request::clone(ExceptionState& exceptionState)
 {
     if (bodyUsed()) {
         exceptionState.throwTypeError("Request body is already used");
         return nullptr;
     }
 
-    FetchRequestData* request = m_request->clone();
-    if (blobDataHandle() && isBodyConsumed()) {
-        // Currently the only methods that can consume body data without
-        // setting 'body passed' flag consume entire body (e.g. text()). Thus
-        // we can set an empty blob to the new request instead of creating a
-        // draining stream.
-        // TODO(yhirano): Fix this once Request.body is introduced.
-        OwnPtr<BlobData> blobData = BlobData::create();
-        blobData->setContentType(blobDataHandle()->type());
-        request->setBlobDataHandle(BlobDataHandle::create(blobData.release(), 0));
-    }
+    if (OwnPtr<DrainingBodyStreamBuffer> buffer = createDrainingStream())
+        m_request->setBuffer(buffer->leak());
 
+    FetchRequestData* request = m_request->clone(executionContext());
     Headers* headers = Headers::create(request->headerList());
     headers->setGuard(m_headers->guard());
     Request* r = new Request(executionContext(), request, headers);
     r->suspendIfNeeded();
+
+    // Lock the old body and set |body| property to the new one.
+    lockBody();
+    refreshBody();
     return r;
 }
 
 FetchRequestData* Request::passRequestData()
 {
     ASSERT(!bodyUsed());
+
+    if (OwnPtr<DrainingBodyStreamBuffer> buffer = createDrainingStream())
+        m_request->setBuffer(buffer->leak());
+
     lockBody(PassBody);
-    return m_request->pass();
+    FetchRequestData* newRequestData = m_request->pass(executionContext());
+    refreshBody();
+    return newRequestData;
 }
 
 void Request::populateWebServiceWorkerRequest(WebServiceWorkerRequest& webRequest) const
 {
     webRequest.setMethod(method());
     webRequest.setRequestContext(m_request->context());
     // This strips off the fragment part.
     webRequest.setURL(url());
 
     const FetchHeaderList* headerList = m_headers->headerList();
     for (size_t i = 0, size = headerList->size(); i < size; ++i) {
         const FetchHeaderList::Header& header = headerList->entry(i);
         webRequest.appendHeader(header.first, header.second);
     }
 
     webRequest.setReferrer(m_request->referrer().referrer().referrer, static_cast<WebReferrerPolicy>(m_request->referrer().referrer().referrerPolicy));
     // FIXME: How can we set isReload properly? What is the correct place to load it in to the Request object? We should investigate the right way
     // to plumb this information in to here.
 }
 
-void Request::setBodyBlobHandle(PassRefPtr<BlobDataHandle> blobDataHandle)
+void Request::setBuffer(BodyStreamBuffer* buffer)
 {
-    m_request->setBlobDataHandle(blobDataHandle);
-    setBody(m_request->blobDataHandle());
+    m_request->setBuffer(buffer);
+    refreshBody();
+}
+
+void Request::refreshBody()
+{
+    setBody(m_request->buffer());
 }
 
 void Request::clearHeaderList()
 {
     m_request->headerList()->clearList();
 }
 
-PassRefPtr<BlobDataHandle> Request::blobDataHandle() const
-{
-    return m_request->blobDataHandle();
-}
-
-BodyStreamBuffer* Request::buffer() const
-{
-    // We don't support BodyStreamBuffer for Request yet.
-    return nullptr;
-}
-
 String Request::mimeType() const
 {
     return m_request->mimeType();
 }
 
 DEFINE_TRACE(Request)
 {
     Body::trace(visitor);
     visitor->trace(m_request);
     visitor->trace(m_headers);
 }
 
 } // namespace blink