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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at */
#ifndef mozilla_dom_Fetch_h
#define mozilla_dom_Fetch_h
#include "nsCOMPtr.h"
#include "nsError.h"
#include "nsProxyRelease.h"
#include "nsString.h"
#include "mozilla/DebugOnly.h"
#include "mozilla/dom/AbortSignal.h"
#include "mozilla/dom/BodyConsumer.h"
#include "mozilla/dom/BodyStream.h"
#include "mozilla/dom/Promise.h"
#include "mozilla/dom/FetchStreamReader.h"
#include "mozilla/dom/RequestBinding.h"
class nsIGlobalObject;
class nsIEventTarget;
namespace mozilla {
class ErrorResult;
namespace dom {
class BlobOrArrayBufferViewOrArrayBufferOrFormDataOrURLSearchParamsOrUSVString;
class BlobImpl;
class InternalRequest;
struct ReadableStream;
class RequestOrUSVString;
class WorkerPrivate;
enum class CallerType : uint32_t;
already_AddRefed<Promise> FetchRequest(nsIGlobalObject* aGlobal,
const RequestOrUSVString& aInput,
const RequestInit& aInit,
CallerType aCallerType,
ErrorResult& aRv);
nsresult UpdateRequestReferrer(nsIGlobalObject* aGlobal,
InternalRequest* aRequest);
namespace fetch {
typedef BlobOrArrayBufferViewOrArrayBufferOrFormDataOrURLSearchParamsOrUSVString
typedef BlobOrArrayBufferViewOrArrayBufferOrFormDataOrURLSearchParamsOrReadableStreamOrUSVString
typedef OwningBlobOrArrayBufferViewOrArrayBufferOrFormDataOrURLSearchParamsOrUSVString
}; // namespace fetch
* Creates an nsIInputStream based on the fetch specifications 'extract a byte
* Stores content type in out param aContentType.
nsresult ExtractByteStreamFromBody(const fetch::OwningBodyInit& aBodyInit,
nsIInputStream** aStream,
nsCString& aContentType,
uint64_t& aContentLength);
* Non-owning version.
nsresult ExtractByteStreamFromBody(const fetch::BodyInit& aBodyInit,
nsIInputStream** aStream,
nsCString& aContentType,
uint64_t& aContentLength);
* Non-owning version. This method should go away when BodyInit will contain
* ReadableStream.
nsresult ExtractByteStreamFromBody(const fetch::ResponseBodyInit& aBodyInit,
nsIInputStream** aStream,
nsCString& aContentType,
uint64_t& aContentLength);
* FetchBody's body consumption uses nsIInputStreamPump to read from the
* underlying stream to a block of memory, which is then adopted by
* ContinueConsumeBody() and converted to the right type based on the JS
* function called.
* Use of the nsIInputStreamPump complicates things on the worker thread.
* The solution used here is similar to WebSockets.
* The difference is that we are only interested in completion and not data
* events, and nsIInputStreamPump can only deliver completion on the main
* thread.
* Before starting the pump on the main thread, we addref the FetchBody to keep
* it alive. Then we add a feature, to track the status of the worker.
* ContinueConsumeBody() is the function that cleans things up in both success
* and error conditions and so all callers call it with the appropriate status.
* Once the read is initiated on the main thread there are two possibilities.
* 1) Pump finishes before worker has finished Running.
* In this case we adopt the data and dispatch a runnable to the worker,
* which derefs FetchBody and removes the feature and resolves the Promise.
* 2) Pump still working while worker has stopped Running.
* The feature is Notify()ed and ContinueConsumeBody() is called with
* NS_BINDING_ABORTED. We first Cancel() the pump using a sync runnable to
* ensure that mFetchBody remains alive (since mConsumeBodyPump is strongly
* held by it) until pump->Cancel() is called. OnStreamComplete() will not
* do anything if the error code is NS_BINDING_ABORTED, so we don't have to
* worry about keeping anything alive.
* The pump is always released on the main thread.
template <class Derived>
class FetchBody : public BodyStreamHolder, public AbortFollower {
using BodyStreamHolder::QueryInterface;
bool GetBodyUsed(ErrorResult& aRv) const;
// For use in assertions. On success, returns true if the body is used, false
// if not. On error, this sweeps the error under the rug and returns true.
bool CheckBodyUsed() const;
already_AddRefed<Promise> ArrayBuffer(JSContext* aCx, ErrorResult& aRv) {
return ConsumeBody(aCx, BodyConsumer::CONSUME_ARRAYBUFFER, aRv);
already_AddRefed<Promise> Blob(JSContext* aCx, ErrorResult& aRv) {
return ConsumeBody(aCx, BodyConsumer::CONSUME_BLOB, aRv);
already_AddRefed<Promise> FormData(JSContext* aCx, ErrorResult& aRv) {
return ConsumeBody(aCx, BodyConsumer::CONSUME_FORMDATA, aRv);
already_AddRefed<Promise> Json(JSContext* aCx, ErrorResult& aRv) {
return ConsumeBody(aCx, BodyConsumer::CONSUME_JSON, aRv);
already_AddRefed<Promise> Text(JSContext* aCx, ErrorResult& aRv) {
return ConsumeBody(aCx, BodyConsumer::CONSUME_TEXT, aRv);
void GetBody(JSContext* aCx, JS::MutableHandle<JSObject*> aBodyOut,
ErrorResult& aRv);
void GetMimeType(nsACString& aMimeType);
const nsACString& BodyBlobURISpec() const;
const nsAString& BodyLocalPath() const;
// If the body contains a ReadableStream body object, this method produces a
// tee() of it.
void MaybeTeeReadableStreamBody(JSContext* aCx,
JS::MutableHandle<JSObject*> aBodyOut,
FetchStreamReader** aStreamReader,
nsIInputStream** aInputStream,
ErrorResult& aRv);
// Utility public methods accessed by various runnables.
// This method _must_ be called in order to set the body as used. If the body
// is a ReadableStream, this method will start reading the stream.
// More in details, this method does:
// 1) It uses an internal flag to track if the body is used. This is tracked
// separately from the ReadableStream disturbed state due to purely native
// streams.
// 2) If there is a ReadableStream reflector for the native stream it is
// Locked.
// 3) If there is a JS ReadableStream then we begin pumping it into the native
// body stream. This effectively locks and disturbs the stream.
// Note that JSContext is used only if there is a ReadableStream (this can
// happen because the body is a ReadableStream or because attribute body has
// already been used by content). If something goes wrong using
// ReadableStream, errors will be reported via ErrorResult and not as JS
// exceptions in JSContext. This is done in order to have a centralized error
// reporting way.
// Exceptions generated when reading from the ReadableStream are directly sent
// to the Console.
void SetBodyUsed(JSContext* aCx, ErrorResult& aRv);
// BodyStreamHolder
void NullifyStream() override {
mReadableStreamBody = nullptr;
mReadableStreamReader = nullptr;
mFetchStreamReader = nullptr;
void SetReadableStreamBody(JSObject* aBody) override {
mReadableStreamBody = aBody;
JSObject* GetReadableStreamBody() override { return mReadableStreamBody; }
void MarkAsRead() override { mBodyUsed = true; }
virtual AbortSignalImpl* GetSignalImpl() const = 0;
// AbortFollower
void RunAbortAlgorithm() override;
already_AddRefed<Promise> ConsumeBody(JSContext* aCx,
BodyConsumer::ConsumeType aType,
ErrorResult& aRv);
nsCOMPtr<nsIGlobalObject> mOwner;
// Always set whenever the FetchBody is created on the worker thread.
WorkerPrivate* mWorkerPrivate;
// This is the ReadableStream exposed to content. It's underlying source is a
// BodyStream object.
JS::Heap<JSObject*> mReadableStreamBody;
// This is the Reader used to retrieve data from the body.
JS::Heap<JSObject*> mReadableStreamReader;
RefPtr<FetchStreamReader> mFetchStreamReader;
explicit FetchBody(nsIGlobalObject* aOwner);
virtual ~FetchBody();
void SetReadableStreamBody(JSContext* aCx, JSObject* aBody);
Derived* DerivedClass() const {
return static_cast<Derived*>(const_cast<FetchBody*>(this));
void LockStream(JSContext* aCx, JS::HandleObject aStream, ErrorResult& aRv);
bool IsOnTargetThread() { return NS_IsMainThread() == !mWorkerPrivate; }
void AssertIsOnTargetThread() { MOZ_ASSERT(IsOnTargetThread()); }
// Only ever set once, always on target thread.
bool mBodyUsed;
// The main-thread event target for runnable dispatching.
nsCOMPtr<nsIEventTarget> mMainThreadEventTarget;
} // namespace dom
} // namespace mozilla
#endif // mozilla_dom_Fetch_h