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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 SimpleChannel_h
#define SimpleChannel_h
#include "mozilla/ResultExtensions.h"
#include "mozilla/UniquePtr.h"
#include "nsBaseChannel.h"
#include "nsIChildChannel.h"
#include "mozilla/net/PSimpleChannelChild.h"
#include "nsCOMPtr.h"
class nsIChannel;
class nsIInputStream;
class nsILoadInfo;
class nsIRequest;
class nsIStreamListener;
class nsIURI;
namespace mozilla {
using InputStreamOrReason = Result<nsCOMPtr<nsIInputStream>, nsresult>;
using NotNullRequest = NotNull<nsCOMPtr<nsIRequest>>;
using NotNullCancelable = NotNull<nsCOMPtr<nsICancelable>>;
using RequestOrCancelable = Variant<NotNullRequest, NotNullCancelable>;
using RequestOrReason = Result<RequestOrCancelable, nsresult>;
namespace net {
class SimpleChannelCallbacks {
virtual InputStreamOrReason OpenContentStream(bool async,
nsIChannel* channel) = 0;
virtual RequestOrReason StartAsyncRead(nsIStreamListener* stream,
nsIChannel* channel) = 0;
virtual ~SimpleChannelCallbacks() = default;
template <typename F1, typename F2, typename T>
class SimpleChannelCallbacksImpl final : public SimpleChannelCallbacks {
SimpleChannelCallbacksImpl(F1&& aStartAsyncRead, F2&& aOpenContentStream,
T* context)
: mStartAsyncRead(aStartAsyncRead),
mContext(context) {}
virtual ~SimpleChannelCallbacksImpl() = default;
virtual InputStreamOrReason OpenContentStream(bool async,
nsIChannel* channel) override {
return mOpenContentStream(async, channel, mContext);
virtual RequestOrReason StartAsyncRead(nsIStreamListener* listener,
nsIChannel* channel) override {
return mStartAsyncRead(listener, channel, mContext);
F1 mStartAsyncRead;
F2 mOpenContentStream;
RefPtr<T> mContext;
class SimpleChannel : public nsBaseChannel {
explicit SimpleChannel(UniquePtr<SimpleChannelCallbacks>&& aCallbacks);
virtual ~SimpleChannel() = default;
virtual nsresult OpenContentStream(bool async, nsIInputStream** streamOut,
nsIChannel** channel) override;
virtual nsresult BeginAsyncRead(nsIStreamListener* listener,
nsIRequest** request,
nsICancelable** cancelableRequest) override;
UniquePtr<SimpleChannelCallbacks> mCallbacks;
class SimpleChannelChild final : public SimpleChannel,
public nsIChildChannel,
public PSimpleChannelChild {
explicit SimpleChannelChild(UniquePtr<SimpleChannelCallbacks>&& aCallbacks);
virtual ~SimpleChannelChild() = default;
already_AddRefed<nsIChannel> NS_NewSimpleChannelInternal(
nsIURI* aURI, nsILoadInfo* aLoadInfo,
UniquePtr<SimpleChannelCallbacks>&& aCallbacks);
} // namespace net
} // namespace mozilla
* Creates a simple channel which wraps an input stream created by the given
* callbacks. The callbacks are not called until the underlying AsyncOpen or
* Open methods are called, and correspond to the nsBaseChannel::StartAsyncRead
* and nsBaseChannel::OpenContentStream methods of the same names.
* The last two arguments of each callback are the created channel instance,
* and the ref-counted context object passed to NS_NewSimpleChannel. A strong
* reference to that object is guaranteed to be kept alive until after a
* callback successfully completes.
template <typename T, typename F1, typename F2>
inline already_AddRefed<nsIChannel> NS_NewSimpleChannel(
nsIURI* aURI, nsILoadInfo* aLoadInfo, T* context, F1&& aStartAsyncRead,
F2&& aOpenContentStream) {
using namespace mozilla;
auto callbacks = MakeUnique<net::SimpleChannelCallbacksImpl<F1, F2, T>>(
std::forward<F1>(aStartAsyncRead), std::forward<F2>(aOpenContentStream),
return net::NS_NewSimpleChannelInternal(aURI, aLoadInfo,
template <typename T, typename F1>
inline already_AddRefed<nsIChannel> NS_NewSimpleChannel(nsIURI* aURI,
nsILoadInfo* aLoadInfo,
T* context,
F1&& aStartAsyncRead) {
using namespace mozilla;
auto openContentStream = [](bool async, nsIChannel* channel, T* context) {
return NS_NewSimpleChannel(aURI, aLoadInfo, context,
#endif // SimpleChannel_h