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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 nsBaseChannel_h__
#define nsBaseChannel_h__
#include "mozilla/net/NeckoTargetHolder.h"
#include "mozilla/Maybe.h"
#include "mozilla/MozPromise.h"
#include "mozilla/UniquePtr.h"
#include "nsString.h"
#include "nsCOMPtr.h"
#include "nsHashPropertyBag.h"
#include "nsInputStreamPump.h"
#include "nsIChannel.h"
#include "nsIURI.h"
#include "nsILoadGroup.h"
#include "nsILoadInfo.h"
#include "nsIStreamListener.h"
#include "nsIInterfaceRequestor.h"
#include "nsIProgressEventSink.h"
#include "nsITransport.h"
#include "nsIAsyncVerifyRedirectCallback.h"
#include "nsIThreadRetargetableRequest.h"
#include "nsIThreadRetargetableStreamListener.h"
#include "mozilla/net/PrivateBrowsingChannel.h"
#include "nsThreadUtils.h"
class nsIInputStream;
class nsICancelable;
// nsBaseChannel is designed to be subclassed. The subclass is responsible for
// implementing the OpenContentStream method, which will be called by the
// nsIChannel::AsyncOpen and nsIChannel::Open implementations.
// nsBaseChannel implements nsIInterfaceRequestor to provide a convenient way
// for subclasses to query both the nsIChannel::notificationCallbacks and
// nsILoadGroup::notificationCallbacks for supported interfaces.
// nsBaseChannel implements nsITransportEventSink to support progress & status
// notifications generated by the transport layer.
class nsBaseChannel
: public nsHashPropertyBag,
public nsIChannel,
public nsIThreadRetargetableRequest,
public nsIInterfaceRequestor,
public nsITransportEventSink,
public nsIAsyncVerifyRedirectCallback,
public mozilla::net::PrivateBrowsingChannel<nsBaseChannel>,
public mozilla::net::NeckoTargetHolder,
protected nsIStreamListener,
protected nsIThreadRetargetableStreamListener {
// -----------------------------------------------
// Methods to be implemented by the derived class:
virtual ~nsBaseChannel();
using BlockingPromise = mozilla::MozPromise<nsresult, nsresult, true>;
// Implemented by subclass to supply data stream. The parameter, async, is
// true when called from nsIChannel::AsyncOpen and false otherwise. When
// async is true, the resulting stream will be used with a nsIInputStreamPump
// instance. This means that if it is a non-blocking stream that supports
// nsIAsyncInputStream that it will be read entirely on the main application
// thread, and its AsyncWait method will be called whenever ReadSegments
// returns NS_BASE_STREAM_WOULD_BLOCK. Otherwise, if the stream is blocking,
// then it will be read on one of the background I/O threads, and it does not
// need to implement ReadSegments. If async is false, this method may return
// NS_ERROR_NOT_IMPLEMENTED to cause the basechannel to implement Open in
// terms of AsyncOpen (see NS_ImplementChannelOpen).
// A callee is allowed to return an nsIChannel instead of an nsIInputStream.
// That case will be treated as a redirect to the new channel. By default
// *channel will be set to null by the caller, so callees who don't want to
// return one an just not touch it.
virtual nsresult OpenContentStream(bool async, nsIInputStream** stream,
nsIChannel** channel) = 0;
// Implemented by subclass to begin pumping data for an async channel, in
// lieu of returning a stream. If implemented, OpenContentStream will never
// be called for async channels. If not implemented, AsyncOpen will fall
// back to OpenContentStream.
// On success, the callee must begin pumping data to the stream listener,
// and at some point call OnStartRequest followed by OnStopRequest.
// Additionally, when a successful nsresult is returned, then the subclass
// should be setting through its two out params either:
// - a request object, which may be used to suspend, resume, and cancel
// the underlying request.
// - or a cancelable object (e.g. when a request can't be returned right away
// due to some async work needed to retrieve it). which may be used to
// cancel the underlying request (e.g. because the channel has been
// canceled)
// Not returning a request or cancelable leads to potentially leaking the
// an underling stream pump (which would keep to be pumping data even after
// the channel has been canceled and nothing is going to handle the data
// available, e.g. see Bug 1706594).
virtual nsresult BeginAsyncRead(nsIStreamListener* listener,
nsIRequest** request,
nsICancelable** cancelableRequest) {
// This method may return a promise that will keep the input stream pump
// suspended until the promise is resolved or rejected. On resolution the
// pump is resumed. On rejection the channel is canceled with the resulting
// error and then the pump is also resumed to propagate the error to the
// channel listener. Use it to do any asynchronous/background tasks you need
// to finish prior calling OnStartRequest of the listener. This method is
// called right after OpenContentStream() with async == true, after the input
// stream pump has already been called asyncRead().
virtual nsresult ListenerBlockingPromise(BlockingPromise** aPromise) {
*aPromise = nullptr;
return NS_OK;
// The basechannel calls this method from its OnTransportStatus method to
// determine whether to call nsIProgressEventSink::OnStatus in addition to
// nsIProgressEventSink::OnProgress. This method may be overriden by the
// subclass to enable nsIProgressEventSink::OnStatus events. If this method
// returns true, then the statusArg out param specifies the "statusArg" value
// to pass to the OnStatus method. By default, OnStatus messages are
// suppressed. The status parameter passed to this method is the status value
// from the OnTransportStatus method.
virtual bool GetStatusArg(nsresult status, nsString& statusArg) {
return false;
// Called when the callbacks available to this channel may have changed.
virtual void OnCallbacksChanged() {}
// Called when our channel is done, to allow subclasses to drop resources.
virtual void OnChannelDone() {}
// ----------------------------------------------
// Methods provided for use by the derived class:
// Redirect to another channel. This method takes care of notifying
// observers of this redirect as well as of opening the new channel, if asked
// to do so. It also cancels |this| with the status code
// NS_BINDING_REDIRECTED. A failure return from this method means that the
// redirect could not be performed (no channel was opened; this channel
// wasn't canceled.) The redirectFlags parameter consists of the flag values
// defined on nsIChannelEventSink.
nsresult Redirect(nsIChannel* newChannel, uint32_t redirectFlags,
bool openNewChannel);
// Tests whether a type hint was set. Subclasses can use this to decide
// whether to call SetContentType.
// NOTE: This is only reliable if the subclass didn't itself call
// SetContentType, and should also not be called after OpenContentStream.
bool HasContentTypeHint() const;
// The URI member should be initialized before the channel is used, and then
// it should never be changed again until the channel is destroyed.
nsIURI* URI() { return mURI; }
void SetURI(nsIURI* uri) {
NS_ASSERTION(uri, "must specify a non-null URI");
NS_ASSERTION(!mURI, "must not modify URI");
NS_ASSERTION(!mOriginalURI, "how did that get set so early?");
mURI = uri;
mOriginalURI = uri;
nsIURI* OriginalURI() { return mOriginalURI; }
// The security info is a property of the transport-layer, which should be
// assigned by the subclass.
nsISupports* SecurityInfo() { return mSecurityInfo; }
void SetSecurityInfo(nsISupports* info) { mSecurityInfo = info; }
// Test the load flags
bool HasLoadFlag(uint32_t flag) { return (mLoadFlags & flag) != 0; }
// This is a short-cut to calling nsIRequest::IsPending()
virtual bool Pending() const {
return mPumpingData || mWaitingOnAsyncRedirect;
// Helper function for querying the channel's notification callbacks.
template <class T>
void GetCallback(nsCOMPtr<T>& result) {
GetInterface(NS_GET_TEMPLATE_IID(T), getter_AddRefs(result));
// If a subclass does not want to feed transport-layer progress events to the
// base channel via nsITransportEventSink, then it may set this flag to cause
// the base channel to synthesize progress events when it receives data from
// the content stream. By default, progress events are not synthesized.
void EnableSynthesizedProgressEvents(bool enable) {
mSynthProgressEvents = enable;
// Some subclasses may wish to manually insert a stream listener between this
// and the channel's listener. The following methods make that possible.
void SetStreamListener(nsIStreamListener* listener) { mListener = listener; }
nsIStreamListener* StreamListener() { return mListener; }
// Pushes a new stream converter in front of the channel's stream listener.
// The fromType and toType values are passed to nsIStreamConverterService's
// AsyncConvertData method. If invalidatesContentLength is true, then the
// channel's content-length property will be assigned a value of -1. This is
// necessary when the converter changes the length of the resulting data
// stream, which is almost always the case for a "stream converter" ;-)
// This function optionally returns a reference to the new converter.
nsresult PushStreamConverter(const char* fromType, const char* toType,
bool invalidatesContentLength = true,
nsIStreamListener** result = nullptr);
void DisallowThreadRetargeting() { mAllowThreadRetargeting = false; }
virtual void SetupNeckoTarget();
// Called to setup mPump and call AsyncRead on it.
nsresult BeginPumpingData();
// Called when the callbacks available to this channel may have changed.
void CallbacksChanged() {
mProgressSink = nullptr;
mQueriedProgressSink = false;
// Called when our channel is done. This should drop no-longer-needed
// pointers.
void ChannelDone() {
mListener = nullptr;
// Handle an async redirect callback. This will only be called if we
// returned success from AsyncOpen while posting a redirect runnable.
void HandleAsyncRedirect(nsIChannel* newChannel);
void ContinueHandleAsyncRedirect(nsresult result);
nsresult ContinueRedirect();
// start URI classifier if requested
void ClassifyURI();
class RedirectRunnable : public mozilla::Runnable {
RedirectRunnable(nsBaseChannel* chan, nsIChannel* newChannel)
: mozilla::Runnable("nsBaseChannel::RedirectRunnable"),
mNewChannel(newChannel) {
MOZ_ASSERT(newChannel, "Must have channel to redirect to");
NS_IMETHOD Run() override {
return NS_OK;
RefPtr<nsBaseChannel> mChannel;
nsCOMPtr<nsIChannel> mNewChannel;
friend class RedirectRunnable;
RefPtr<nsInputStreamPump> mPump;
RefPtr<nsIRequest> mRequest;
nsCOMPtr<nsICancelable> mCancelableAsyncRequest;
bool mPumpingData{false};
nsCOMPtr<nsIProgressEventSink> mProgressSink;
nsCOMPtr<nsIURI> mOriginalURI;
nsCOMPtr<nsISupports> mOwner;
nsCOMPtr<nsISupports> mSecurityInfo;
nsCOMPtr<nsIChannel> mRedirectChannel;
nsCString mContentType;
nsCString mContentCharset;
uint32_t mLoadFlags{LOAD_NORMAL};
bool mQueriedProgressSink{true};
bool mSynthProgressEvents{false};
bool mAllowThreadRetargeting{true};
bool mWaitingOnAsyncRedirect{false};
bool mOpenRedirectChannel{false};
uint32_t mRedirectFlags{0};
nsCOMPtr<nsIURI> mURI;
nsCOMPtr<nsILoadGroup> mLoadGroup;
nsCOMPtr<nsILoadInfo> mLoadInfo;
nsCOMPtr<nsIInterfaceRequestor> mCallbacks;
nsCOMPtr<nsIStreamListener> mListener;
nsresult mStatus{NS_OK};
uint32_t mContentDispositionHint{UINT32_MAX};
mozilla::UniquePtr<nsString> mContentDispositionFilename;
int64_t mContentLength{-1};
bool mWasOpened{false};
bool mCanceled{false};
friend class mozilla::net::PrivateBrowsingChannel<nsBaseChannel>;
#endif // !nsBaseChannel_h__