gecko-dev/layout/xul/nsScrollbarFrame.h
Masayuki Nakano 780b285e68 Bug 1543315 - part 15: Mark PresShell::ScrollFrameRectIntoView() as MOZ_CAN_RUN_SCRIPT r=smaug
Unfortunately, `EventChainVisitor` does not grab the `nsPresContext` with
`RefPtr` by itself.  Therefore, there is no guarantee of the lifetime without
checking the origin when its subclasses are instantiated.  This patch changes
it and subclasses to `MOZ_STACK_CLASS` since only `EventDispatcher::Dispatch()`
creates them in the stack with given `nsPresContext`.  Additionally, it's
already been marked as MOZ_CAN_RUN_SCRIPT_BOUNDARY`.  Therefore, the
`nsPresContext` instance has already been guaranteed its lifetime by the
caller.  For making this fact stronger, this patch marks their constructors
as `MOZ_CAN_RUN_SCRIPT`.  Therefore, nobody can create those instances without
guaranteeing the lifetime of `nsPresContext` and `dom::Event`.  Note that
it may look like that `mPresContext` of `EventChainPostVisitor` is not
guaranteed.  However, `EventChainPreVisitor` which gives `nsPresContext` to it
is also a stack only class.  So, it won't be deleted before
`EventChainPostVisitor` instance.

Differential Revision: https://phabricator.services.mozilla.com/D30010

--HG--
extra : moz-landing-system : lando
2019-05-06 13:57:46 +00:00

139 lines
4.7 KiB
C++

/* -*- 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/. */
//
// nsScrollbarFrame
//
#ifndef nsScrollbarFrame_h__
#define nsScrollbarFrame_h__
#include "mozilla/Attributes.h"
#include "nsIAnonymousContentCreator.h"
#include "nsBoxFrame.h"
class nsIScrollbarMediator;
namespace mozilla {
class PresShell;
} // namespace mozilla
nsIFrame* NS_NewScrollbarFrame(mozilla::PresShell* aPresShell,
mozilla::ComputedStyle* aStyle);
class nsScrollbarFrame final : public nsBoxFrame,
public nsIAnonymousContentCreator {
public:
explicit nsScrollbarFrame(ComputedStyle* aStyle, nsPresContext* aPresContext)
: nsBoxFrame(aStyle, aPresContext, kClassID),
mIncrement(0),
mSmoothScroll(false),
mScrollbarMediator(nullptr),
mUpTopButton(nullptr),
mDownTopButton(nullptr),
mSlider(nullptr),
mThumb(nullptr),
mUpBottomButton(nullptr),
mDownBottomButton(nullptr) {}
NS_DECL_QUERYFRAME
NS_DECL_FRAMEARENA_HELPERS(nsScrollbarFrame)
#ifdef DEBUG_FRAME_DUMP
virtual nsresult GetFrameName(nsAString& aResult) const override {
return MakeFrameName(NS_LITERAL_STRING("ScrollbarFrame"), aResult);
}
#endif
// nsIFrame overrides
virtual nsresult AttributeChanged(int32_t aNameSpaceID, nsAtom* aAttribute,
int32_t aModType) override;
NS_IMETHOD HandlePress(nsPresContext* aPresContext,
mozilla::WidgetGUIEvent* aEvent,
nsEventStatus* aEventStatus) override;
NS_IMETHOD HandleMultiplePress(nsPresContext* aPresContext,
mozilla::WidgetGUIEvent* aEvent,
nsEventStatus* aEventStatus,
bool aControlHeld) override;
MOZ_CAN_RUN_SCRIPT
NS_IMETHOD HandleDrag(nsPresContext* aPresContext,
mozilla::WidgetGUIEvent* aEvent,
nsEventStatus* aEventStatus) override;
NS_IMETHOD HandleRelease(nsPresContext* aPresContext,
mozilla::WidgetGUIEvent* aEvent,
nsEventStatus* aEventStatus) override;
virtual void DestroyFrom(nsIFrame* aDestructRoot,
PostDestroyData& aPostDestroyData) override;
virtual void Init(nsIContent* aContent, nsContainerFrame* aParent,
nsIFrame* aPrevInFlow) override;
virtual void Reflow(nsPresContext* aPresContext, ReflowOutput& aDesiredSize,
const ReflowInput& aReflowInput,
nsReflowStatus& aStatus) override;
void SetScrollbarMediatorContent(nsIContent* aMediator);
nsIScrollbarMediator* GetScrollbarMediator();
// nsBox methods
/**
* Treat scrollbars as clipping their children; overflowing children
* will not be allowed to set an overflow rect on this
* frame. This means that when the scroll code decides to hide a
* scrollframe by setting its height or width to zero, that will
* hide the children too.
*/
virtual bool DoesClipChildren() override { return true; }
virtual nsresult GetXULMargin(nsMargin& aMargin) override;
/**
* The following three methods set the value of mIncrement when a
* scrollbar button is pressed.
*/
void SetIncrementToLine(int32_t aDirection);
void SetIncrementToPage(int32_t aDirection);
void SetIncrementToWhole(int32_t aDirection);
/**
* MoveToNewPosition() adds mIncrement to the current position and
* updates the curpos attribute.
* @returns The new position after clamping, in CSS Pixels
* @note This method might destroy the frame, pres shell, and other objects.
*/
int32_t MoveToNewPosition();
int32_t GetIncrement() { return mIncrement; }
// nsIAnonymousContentCreator
virtual nsresult CreateAnonymousContent(
nsTArray<ContentInfo>& aElements) override;
virtual void AppendAnonymousContentTo(nsTArray<nsIContent*>& aElements,
uint32_t aFilter) override;
void UpdateChildrenAttributeValue(nsAtom* aAttribute, bool aNotify);
protected:
int32_t mIncrement; // Amount to scroll, in CSSPixels
bool mSmoothScroll;
private:
nsCOMPtr<nsIContent> mScrollbarMediator;
nsCOMPtr<Element> mUpTopButton;
nsCOMPtr<Element> mDownTopButton;
nsCOMPtr<Element> mSlider;
nsCOMPtr<Element> mThumb;
nsCOMPtr<Element> mUpBottomButton;
nsCOMPtr<Element> mDownBottomButton;
}; // class nsScrollbarFrame
#endif