widget/nsAutoRollup.h
author Jan Henning <jh+bugzilla@buttercookie.de>
Fri, 11 Jan 2019 21:21:41 +0000
changeset 453568 0355f47af6ceab050018e9c27fc9d9c4bb944662
parent 448947 6f3709b3878117466168c40affa7bca0b60cf75b
permissions -rw-r--r--
Bug 1517976 - Test that resetting WindowUtils.isFirstPaint doesn't clobber APZ scroll position. r=botond We need to setup a case where the visual viewport is smaller than the layout viewport. Faking a pinch zoom through touch events is imprecise, whereas calling windowUtils.setResolutionAndScaleTo(value > 1) to simulate the equivalent effect of a pinch-zoom on the page led to the subsequent scroll attempt failing quite often even after calling waitForApzFlushedRepaints(). So instead, we set up a very wide layout viewport through the meta viewport tag, which on Desktop means additionally enabling the dom.meta-viewport.enabled pref. Differential Revision: https://phabricator.services.mozilla.com/D15791

/* -*- 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 nsAutoRollup_h__
#define nsAutoRollup_h__

#include "mozilla/Attributes.h"  // for MOZ_RAII
#include "mozilla/StaticPtr.h"   // for StaticRefPtr
#include "nsIContent.h"

namespace mozilla {
namespace widget {

// A situation can occur when a mouse event occurs over a menu label while the
// menu popup is already open. The expected behaviour is to close the popup.
// This happens by calling nsIRollupListener::Rollup before the mouse event is
// processed. However, in cases where the mouse event is not consumed, this
// event will then get targeted at the menu label causing the menu to open
// again. To prevent this, we store in sLastRollup a reference to the popup
// that was closed during the Rollup call, and prevent this popup from
// reopening while processing the mouse event.
// sLastRollup can only be set while an nsAutoRollup is in scope;
// when it goes out of scope sLastRollup is cleared automatically.
// As sLastRollup is static, it can be retrieved by calling
// nsAutoRollup::GetLastRollup.
class MOZ_RAII nsAutoRollup {
 public:
  nsAutoRollup();
  ~nsAutoRollup();

  // Convenience constructor that creates a nsAutoRollup and also sets
  // the last rollup.
  explicit nsAutoRollup(nsIContent* aRollup);

  static void SetLastRollup(nsIContent* aLastRollup);
  // Return the popup that was last rolled up, or null if there isn't one.
  static nsIContent* GetLastRollup();

 private:
  // Whether sLastRollup was clear when this nsAutoRollup
  // was created.
  bool mWasClear;

  // The number of nsAutoRollup instances active.
  static uint32_t sCount;
  // The last rolled up popup.
  static StaticRefPtr<nsIContent> sLastRollup;
};

}  // namespace widget
}  // namespace mozilla

#endif  // nsAutoRollup_h__