netwerk/base/nsAsyncRedirectVerifyHelper.h
author Andrew Osmond <aosmond@mozilla.com>
Fri, 17 Nov 2017 06:45:28 -0500
changeset 392351 b9a29d94ccac646c9336fa75e084bbc8581501ad
parent 367749 6a629adbb62a299d7208373d1c6f375149d2afdb
child 448947 6f3709b3878117466168c40affa7bca0b60cf75b
permissions -rw-r--r--
Bug 1368776 - Part 15. Cache flags passed to ImageResource::GetImageContainerImpl for consistency. r=tnikkel When FLAG_HIGH_QUALITY_SCALING is used, we need to make sure we continue using that flag when we update the container. We should also use it for comparing whether or not an existing image container is equivalent.

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* 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 nsAsyncRedirectVerifyHelper_h
#define nsAsyncRedirectVerifyHelper_h

#include "nsIRunnable.h"
#include "nsIThread.h"
#include "nsIChannelEventSink.h"
#include "nsIInterfaceRequestor.h"
#include "nsIAsyncVerifyRedirectCallback.h"
#include "nsCOMPtr.h"
#include "nsAutoPtr.h"
#include "nsCycleCollectionParticipant.h"
#include "mozilla/Attributes.h"

class nsIChannel;

namespace mozilla {
namespace net {

/**
 * This class simplifies call of OnChannelRedirect of IOService and
 * the sink bound with the channel being redirected while the result of
 * redirect decision is returned through the callback.
 */
class nsAsyncRedirectVerifyHelper final : public nsIRunnable,
                                          public nsINamed,
                                          public nsIAsyncVerifyRedirectCallback
{
    NS_DECL_THREADSAFE_ISUPPORTS
    NS_DECL_NSIRUNNABLE
    NS_DECL_NSINAMED
    NS_DECL_NSIASYNCVERIFYREDIRECTCALLBACK

public:
    nsAsyncRedirectVerifyHelper();

    /*
     * Calls AsyncOnChannelRedirect() on the given sink with the given
     * channels and flags. Keeps track of number of async callbacks to expect.
     */
    nsresult DelegateOnChannelRedirect(nsIChannelEventSink *sink,
                                       nsIChannel *oldChannel,
                                       nsIChannel *newChannel,
                                       uint32_t flags);

    /**
     * Initialize and run the chain of AsyncOnChannelRedirect calls. OldChannel
     * is QI'ed for nsIAsyncVerifyRedirectCallback. The result of the redirect
     * decision is passed through this interface back to the oldChannel.
     *
     * @param oldChan
     *    channel being redirected, MUST implement
     *    nsIAsyncVerifyRedirectCallback
     * @param newChan
     *    target of the redirect channel
     * @param flags
     *    redirect flags
     * @param mainThreadEventTarget
     *    a labeled event target for dispatching runnables
     * @param synchronize
     *    set to TRUE if you want the Init method wait synchronously for
     *    all redirect callbacks
     */
    nsresult Init(nsIChannel* oldChan,
                  nsIChannel* newChan,
                  uint32_t flags,
                  nsIEventTarget* mainThreadEventTarget,
                  bool synchronize = false);

protected:
    nsCOMPtr<nsIChannel> mOldChan;
    nsCOMPtr<nsIChannel> mNewChan;
    uint32_t mFlags;
    bool mWaitingForRedirectCallback;
    nsCOMPtr<nsIEventTarget> mCallbackEventTarget;
    bool                     mCallbackInitiated;
    int32_t                  mExpectedCallbacks;
    nsresult                 mResult; // value passed to callback

    void InitCallback();

    /**
     * Calls back to |oldChan| as described in Init()
     */
    void ExplicitCallback(nsresult result);

private:
    ~nsAsyncRedirectVerifyHelper();

    bool IsOldChannelCanceled();
};

/*
 * Helper to make the call-stack handle some control-flow for us
 */
class nsAsyncRedirectAutoCallback
{
public:
    explicit nsAsyncRedirectAutoCallback(nsIAsyncVerifyRedirectCallback* aCallback)
        : mCallback(aCallback)
    {
        mResult = NS_OK;
    }
    ~nsAsyncRedirectAutoCallback()
    {
        if (mCallback)
            mCallback->OnRedirectVerifyCallback(mResult);
    }
    /*
     * Call this is you want it to call back with a different result-code
     */
    void SetResult(nsresult aRes)
    {
        mResult = aRes;
    }
    /*
     * Call this is you want to avoid the callback
     */
    void DontCallback()
    {
        mCallback = nullptr;
    }
private:
    nsIAsyncVerifyRedirectCallback* mCallback;
    nsresult mResult;
};

} // namespace net
} // namespace mozilla
#endif