xpcom/io/InputStreamLengthWrapper.h
author Jan Henning <jh+bugzilla@buttercookie.de>
Thu, 07 Feb 2019 20:41:16 +0000
changeset 512996 95b884dcbd6f001b990a6353980280050fab9ac6
parent 505383 6f3709b3878117466168c40affa7bca0b60cf75b
child 513527 89e6f6b8ed7a1216d59e20f16b6ee131d1f9263b
permissions -rw-r--r--
Bug 1496684 - Dispatch commonly expected startup notifications when opening a GeckoView window. r=snorp a=lizzard Once a webextension using a blocking WebRequest listener has started loading, all network connections covered by the extension's manifest are held until the extension is ready the process them. One condition for the extension being ready apparently includes browser startup having progressed far enough, as signified by "browser-delayed-startup-finished" having been dispatched. Therefore, we have to start sending that notification when opening a new Gecko- View window, too, and copy Fennec's InitLater() system for that. Unlike Fennec, we cannot tie registration of those InitLater() runnables to the initial content load having progressed far enough because of a) e10s, which makes that approach neither easily possible nor really sensible, as content will load in a different process in that case, and b) because we're racing with extension startup here - if extensions are loaded quick enough to block even the initial page load, we'd be deadlocked: We cannot send the notification until the page finishes loading, but the page cannot load until we send the notification. Fennec isn't affected by the latter problem because "sessionstore-windows-restored", which Fennec will send in any case, serves as an alternative pathway for completing extension startup. And unlike Desktop, we don't really have any chrome content to paint, so we cannot tie delayed initialisation to a paint listener for that, either. Therefore, we simply fire off a runnable at the *end* of geckoview.js's startup() method, which should give more pressing initialisation tasks enough of a headstart. For completeness, we're also adding the "browser-idle-startup-tasks-finished" notification and thereby solve bug 1465832 as well, allowing the ScriptPreloader to detect which scripts are commonly loaded during GeckoView startup and to start caching and pre-parsing them. Differential Revision: https://phabricator.services.mozilla.com/D18865

/* -*- 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 InputStreamLengthWrapper_h
#define InputStreamLengthWrapper_h

#include "mozilla/Attributes.h"
#include "mozilla/Mutex.h"
#include "nsCOMPtr.h"
#include "nsIAsyncInputStream.h"
#include "nsICloneableInputStream.h"
#include "nsIIPCSerializableInputStream.h"
#include "nsISeekableStream.h"
#include "nsIInputStreamLength.h"

namespace mozilla {

// A wrapper keeps an inputStream together with its length.
// This class can be used for nsIInputStreams that do not implement
// nsIInputStreamLength.

class InputStreamLengthWrapper final : public nsIAsyncInputStream,
                                       public nsICloneableInputStream,
                                       public nsIIPCSerializableInputStream,
                                       public nsISeekableStream,
                                       public nsIInputStreamCallback,
                                       public nsIInputStreamLength {
 public:
  NS_DECL_THREADSAFE_ISUPPORTS
  NS_DECL_NSIINPUTSTREAM
  NS_DECL_NSIASYNCINPUTSTREAM
  NS_DECL_NSICLONEABLEINPUTSTREAM
  NS_DECL_NSIIPCSERIALIZABLEINPUTSTREAM
  NS_DECL_NSISEEKABLESTREAM
  NS_DECL_NSITELLABLESTREAM
  NS_DECL_NSIINPUTSTREAMCALLBACK
  NS_DECL_NSIINPUTSTREAMLENGTH

  // This method creates a InputStreamLengthWrapper around aInputStream if
  // this doesn't implement nsIInputStreamLength or
  // nsIInputStreamAsyncLength interface, but it implements
  // nsIAsyncInputStream. For this kind of streams,
  // InputStreamLengthHelper is not able to retrieve the length. This
  // method will make such streams ready to be used with
  // InputStreamLengthHelper.
  static already_AddRefed<nsIInputStream> MaybeWrap(
      already_AddRefed<nsIInputStream> aInputStream, int64_t aLength);

  // The length here will be used when nsIInputStreamLength::Length() is called.
  InputStreamLengthWrapper(already_AddRefed<nsIInputStream> aInputStream,
                           int64_t aLength);

  // This CTOR is meant to be used just for IPC.
  InputStreamLengthWrapper();

 private:
  ~InputStreamLengthWrapper();

  void SetSourceStream(already_AddRefed<nsIInputStream> aInputStream);

  nsCOMPtr<nsIInputStream> mInputStream;

  // Raw pointers because these are just QI of mInputStream.
  nsICloneableInputStream* mWeakCloneableInputStream;
  nsIIPCSerializableInputStream* mWeakIPCSerializableInputStream;
  nsISeekableStream* mWeakSeekableInputStream;
  nsITellableStream* mWeakTellableInputStream;
  nsIAsyncInputStream* mWeakAsyncInputStream;

  int64_t mLength;
  bool mConsumed;

  mozilla::Mutex mMutex;

  // This is used for AsyncWait and it's protected by mutex.
  nsCOMPtr<nsIInputStreamCallback> mAsyncWaitCallback;
};

}  // namespace mozilla

#endif  // InputStreamLengthWrapper_h