netwerk/base/nsAsyncRedirectVerifyHelper.h

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef nsAsyncRedirectVerifyHelper_h
   7 #define nsAsyncRedirectVerifyHelper_h
   8
   9 #include "nsIRunnable.h"
  10 #include "nsIChannelEventSink.h"
  11 #include "nsIAsyncVerifyRedirectCallback.h"
  12 #include "nsINamed.h"
  13 #include "nsCOMPtr.h"
  14 #include "nsCycleCollectionParticipant.h"
  15 #include "mozilla/Attributes.h"
  16
  17 class nsIChannel;
  18
  19 namespace mozilla {
  20 namespace net {
  21
  22 /**
  23  * This class simplifies call of OnChannelRedirect of IOService and
  24  * the sink bound with the channel being redirected while the result of
  25  * redirect decision is returned through the callback.
  26  */
  27 class nsAsyncRedirectVerifyHelper final
  28     : public nsIRunnable,
  29       public nsINamed,
  30       public nsIAsyncVerifyRedirectCallback {
  31   NS_DECL_THREADSAFE_ISUPPORTS
  32   NS_DECL_NSIRUNNABLE
  33   NS_DECL_NSINAMED
  34   NS_DECL_NSIASYNCVERIFYREDIRECTCALLBACK
  35
  36  public:
  37   nsAsyncRedirectVerifyHelper() = default;
  38
  39   /*
  40    * Calls AsyncOnChannelRedirect() on the given sink with the given
  41    * channels and flags. Keeps track of number of async callbacks to expect.
  42    */
  43   nsresult DelegateOnChannelRedirect(nsIChannelEventSink* sink,
  44                                      nsIChannel* oldChannel,
  45                                      nsIChannel* newChannel, uint32_t flags);
  46
  47   /**
  48    * Initialize and run the chain of AsyncOnChannelRedirect calls. OldChannel
  49    * is QI'ed for nsIAsyncVerifyRedirectCallback. The result of the redirect
  50    * decision is passed through this interface back to the oldChannel.
  51    *
  52    * @param oldChan
  53    *    channel being redirected, MUST implement
  54    *    nsIAsyncVerifyRedirectCallback
  55    * @param newChan
  56    *    target of the redirect channel
  57    * @param flags
  58    *    redirect flags
  59    * @param mainThreadEventTarget
  60    *    a labeled event target for dispatching runnables
  61    * @param synchronize
  62    *    set to TRUE if you want the Init method wait synchronously for
  63    *    all redirect callbacks
  64    */
  65   nsresult Init(nsIChannel* oldChan, nsIChannel* newChan, uint32_t flags,
  66                 nsIEventTarget* mainThreadEventTarget,
  67                 bool synchronize = false);
  68
  69  protected:
  70   nsCOMPtr<nsIChannel> mOldChan;
  71   nsCOMPtr<nsIChannel> mNewChan;
  72   uint32_t mFlags{0};
  73   bool mWaitingForRedirectCallback{false};
  74   nsCOMPtr<nsIEventTarget> mCallbackEventTarget;
  75   bool mCallbackInitiated{false};
  76   int32_t mExpectedCallbacks{0};
  77   nsresult mResult{NS_OK};  // value passed to callback
  78
  79   void InitCallback();
  80
  81   /**
  82    * Calls back to |oldChan| as described in Init()
  83    */
  84   void ExplicitCallback(nsresult result);
  85
  86  private:
  87   ~nsAsyncRedirectVerifyHelper();
  88
  89   bool IsOldChannelCanceled();
  90 };
  91
  92 /*
  93  * Helper to make the call-stack handle some control-flow for us
  94  */
  95 class nsAsyncRedirectAutoCallback {
  96  public:
  97   explicit nsAsyncRedirectAutoCallback(
  98       nsIAsyncVerifyRedirectCallback* aCallback)
  99       : mCallback(aCallback) {
 100     mResult = NS_OK;
 101   }
 102   ~nsAsyncRedirectAutoCallback() {
 103     if (mCallback) mCallback->OnRedirectVerifyCallback(mResult);
 104   }
 105   /*
 106    * Call this is you want it to call back with a different result-code
 107    */
 108   void SetResult(nsresult aRes) { mResult = aRes; }
 109   /*
 110    * Call this is you want to avoid the callback
 111    */
 112   void DontCallback() { mCallback = nullptr; }
 113
 114  private:
 115   nsIAsyncVerifyRedirectCallback* mCallback;
 116   nsresult mResult;
 117 };
 118
 119 }  // namespace net
 120 }  // namespace mozilla
 121 #endif