author Chris H-C <chutten@mozilla.com>
Fri, 12 Aug 2016 14:51:48 -0400
changeset 314448 c97a5b2b086accd52fb5dd0b27eb6d5127fb6fc8
parent 268184 e8c7dfe727cd970e2c3294934e2927b14143c205
permissions -rw-r--r--
bug 1218576 - Aggregate child categorical histograms in the parent process. r=gfritzsche Rewrite the categorical histogram accumulation code to use the common path. This way it gets remote accumulation for cheap. MozReview-Commit-ID: 3q6gdSvBix

/* -*- 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 http://mozilla.org/MPL/2.0/. */

#ifndef nsScreenManagerProxy_h
#define nsScreenManagerProxy_h

#include "nsIScreenManager.h"
#include "mozilla/dom/PScreenManagerChild.h"
#include "mozilla/dom/TabChild.h"
#include "ScreenProxy.h"

 * The nsScreenManagerProxy is used by the content process to get
 * information about system screens. It uses the PScreenManager protocol
 * to communicate with a PScreenManagerParent to get this information,
 * and also caches the information it gets back.
 * We cache both the system screen information that nsIScreenManagers
 * provide, as well as the nsIScreens that callers can query for.
 * Both of these caches are invalidated on the next tick of the event
 * loop.
class nsScreenManagerProxy final : public nsIScreenManager,
                                   public mozilla::dom::PScreenManagerChild


  ~nsScreenManagerProxy() {};

  bool EnsureCacheIsValid();
  void InvalidateCacheOnNextTick();
  void InvalidateCache();

  uint32_t mNumberOfScreens;
  float mSystemDefaultScale;
  bool mCacheValid;
  bool mCacheWillInvalidate;

  RefPtr<mozilla::widget::ScreenProxy> mPrimaryScreen;

  // nsScreenManagerProxy caches the results to repeated calls to
  // ScreenForNativeWidget, which can be triggered indirectly by
  // web content using the DOM Screen API. This allows us to bypass
  // a lot of IPC traffic.
  // The cache stores ScreenProxy's mapped to the TabChild that
  // asked for the ScreenForNativeWidget was called with via
  // ScreenCacheEntry's. The cache is cleared on the next tick of
  // the event loop.
  struct ScreenCacheEntry
    RefPtr<mozilla::widget::ScreenProxy> mScreenProxy;
    RefPtr<mozilla::dom::TabChild> mTabChild;

  nsTArray<ScreenCacheEntry> mScreenCache;

#endif // nsScreenManagerProxy_h