gecko-dev/dom/fetch/Fetch.h

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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 http://mozilla.org/MPL/2.0/. */
#ifndef mozilla_dom_Fetch_h
#define mozilla_dom_Fetch_h
#include "nsAutoPtr.h"
#include "nsIStreamLoader.h"
#include "nsCOMPtr.h"
#include "nsError.h"
#include "nsProxyRelease.h"
#include "nsString.h"
#include "mozilla/DebugOnly.h"
#include "mozilla/ErrorResult.h"
#include "mozilla/dom/AbortSignal.h"
#include "mozilla/dom/Promise.h"
#include "mozilla/dom/FetchStreamReader.h"
#include "mozilla/dom/RequestBinding.h"
class nsIGlobalObject;
class nsIEventTarget;
namespace mozilla {
namespace dom {
class BlobOrArrayBufferViewOrArrayBufferOrFormDataOrURLSearchParamsOrUSVString;
class BlobOrArrayBufferViewOrArrayBufferOrFormDataOrURLSearchParamsOrReadableStreamOrUSVString;
class BlobImpl;
class InternalRequest;
class OwningBlobOrArrayBufferViewOrArrayBufferOrFormDataOrURLSearchParamsOrUSVString;
struct ReadableStream;
class RequestOrUSVString;
enum class CallerType : uint32_t;
namespace workers {
class WorkerPrivate;
} // namespace workers
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 BodyInit;
typedef BlobOrArrayBufferViewOrArrayBufferOrFormDataOrURLSearchParamsOrReadableStreamOrUSVString ResponseBodyInit;
typedef OwningBlobOrArrayBufferViewOrArrayBufferOrFormDataOrURLSearchParamsOrUSVString OwningBodyInit;
};
/*
* Creates an nsIInputStream based on the fetch specifications 'extract a byte
* stream algorithm' - http://fetch.spec.whatwg.org/#concept-bodyinit-extract.
* 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);
template <class Derived> class FetchBodyConsumer;
enum FetchConsumeType
{
CONSUME_ARRAYBUFFER,
CONSUME_BLOB,
CONSUME_FORMDATA,
CONSUME_JSON,
CONSUME_TEXT,
};
class FetchStreamHolder
{
public:
NS_INLINE_DECL_PURE_VIRTUAL_REFCOUNTING
virtual void
NullifyStream() = 0;
virtual JSObject*
ReadableStreamBody() = 0;
};
/*
* 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 FetchStreamHolder
, public AbortFollower
{
public:
friend class FetchBodyConsumer<Derived>;
bool
BodyUsed() const;
already_AddRefed<Promise>
ArrayBuffer(JSContext* aCx, ErrorResult& aRv)
{
return ConsumeBody(aCx, CONSUME_ARRAYBUFFER, aRv);
}
already_AddRefed<Promise>
Blob(JSContext* aCx, ErrorResult& aRv)
{
return ConsumeBody(aCx, CONSUME_BLOB, aRv);
}
already_AddRefed<Promise>
FormData(JSContext* aCx, ErrorResult& aRv)
{
return ConsumeBody(aCx, CONSUME_FORMDATA, aRv);
}
already_AddRefed<Promise>
Json(JSContext* aCx, ErrorResult& aRv)
{
return ConsumeBody(aCx, CONSUME_JSON, aRv);
}
already_AddRefed<Promise>
Text(JSContext* aCx, ErrorResult& aRv)
{
return ConsumeBody(aCx, CONSUME_TEXT, aRv);
}
void
GetBody(JSContext* aCx,
JS::MutableHandle<JSObject*> aBodyOut,
ErrorResult& aRv);
// 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);
const nsCString&
MimeType() const
{
return mMimeType;
}
// FetchStreamHolder
void
NullifyStream() override
{
mReadableStreamBody = nullptr;
mReadableStreamReader = nullptr;
mFetchStreamReader = nullptr;
}
JSObject*
ReadableStreamBody() override
{
MOZ_ASSERT(mReadableStreamBody);
return mReadableStreamBody;
}
virtual AbortSignal*
GetSignal() const = 0;
// AbortFollower
void
Abort() override;
protected:
nsCOMPtr<nsIGlobalObject> mOwner;
// Always set whenever the FetchBody is created on the worker thread.
workers::WorkerPrivate* mWorkerPrivate;
// This is the ReadableStream exposed to content. It's underlying source is a
// FetchStream 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
SetMimeType();
void
SetReadableStreamBody(JSContext* aCx, JSObject* aBody);
private:
Derived*
DerivedClass() const
{
return static_cast<Derived*>(const_cast<FetchBody*>(this));
}
already_AddRefed<Promise>
ConsumeBody(JSContext* aCx, FetchConsumeType aType, ErrorResult& aRv);
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;
nsCString mMimeType;
// The main-thread event target for runnable dispatching.
nsCOMPtr<nsIEventTarget> mMainThreadEventTarget;
};
} // namespace dom
} // namespace mozilla
#endif // mozilla_dom_Fetch_h