gecko-dev/widget/windows/TaskbarPreview.h
Toshihito Kikuchi cba747de45 Bug 1661485 - Make TaskbarPreview::GetWindowHook() return a pointer. r=cmartin
Our telemetry data showed `WinUtils::GetNSWindowPtr` returned nullptr
when constructing `TaskbarTabPreview`.  We can't find a way to make such
a situation, but these crashes tell us we should not assume `GetNSWindowPtr`
always returns a valid pointer.

A proposed fix is to change the return value of `GetWindowHook()` from
a reference to a pointer so that the caller can decide what to do
when nullptr is returned.

Differential Revision: https://phabricator.services.mozilla.com/D91471
2020-09-28 21:22:11 +00:00

133 lines
4.0 KiB
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/* vim: se cin sw=2 ts=2 et : */
/* -*- 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 __mozilla_widget_TaskbarPreview_h__
#define __mozilla_widget_TaskbarPreview_h__
#include <windows.h>
#include <shobjidl.h>
#undef LogSeverity // SetupAPI.h #defines this as DWORD
#include "mozilla/RefPtr.h"
#include <nsITaskbarPreview.h>
#include <nsITaskbarPreviewController.h>
#include <nsString.h>
#include <nsIWeakReferenceUtils.h>
#include <nsIDocShell.h>
#include "WindowHook.h"
namespace mozilla {
namespace widget {
class TaskbarPreviewCallback;
class TaskbarPreview : public nsITaskbarPreview {
public:
TaskbarPreview(ITaskbarList4* aTaskbar,
nsITaskbarPreviewController* aController, HWND aHWND,
nsIDocShell* aShell);
virtual nsresult Init();
friend class TaskbarPreviewCallback;
NS_DECL_NSITASKBARPREVIEW
protected:
virtual ~TaskbarPreview();
// Called to update ITaskbarList4 dependent properties
virtual nsresult UpdateTaskbarProperties();
// Invoked when the preview is made visible
virtual nsresult Enable();
// Invoked when the preview is made invisible
virtual nsresult Disable();
// Detaches this preview from the nsWindow instance it's tied to
virtual void DetachFromNSWindow();
// Determines if the window is available and a destroy has not yet started
bool IsWindowAvailable() const;
// Marks this preview as being active
virtual nsresult ShowActive(bool active) = 0;
// Gets a reference to the window used to handle the preview messages
virtual HWND& PreviewWindow() = 0;
// Window procedure for the PreviewWindow (hooked for window previews)
virtual LRESULT WndProc(UINT nMsg, WPARAM wParam, LPARAM lParam);
// Returns whether or not the taskbar icon has been created for mWnd The
// ITaskbarList4 API requires that we wait until the icon has been created
// before we can call its methods.
bool CanMakeTaskbarCalls();
// Gets the WindowHook for the nsWindow
WindowHook* GetWindowHook();
// Enables/disables custom drawing for the given window
static void EnableCustomDrawing(HWND aHWND, bool aEnable);
// MSCOM Taskbar interface
RefPtr<ITaskbarList4> mTaskbar;
// Controller for this preview
nsCOMPtr<nsITaskbarPreviewController> mController;
// The HWND to the nsWindow that this object previews
HWND mWnd;
// Whether or not this preview is visible
bool mVisible;
private:
// Called when the tooltip should be updated
nsresult UpdateTooltip();
// Requests the controller to draw into a canvas of the given width and
// height. The resulting bitmap is sent to the DWM to display.
void DrawBitmap(uint32_t width, uint32_t height, bool isPreview);
// WindowHook procedure for hooking mWnd
static bool MainWindowHook(void* aContext, HWND hWnd, UINT nMsg,
WPARAM wParam, LPARAM lParam, LRESULT* aResult);
// Docshell corresponding to the <window> the nsWindow contains
nsWeakPtr mDocShell;
nsString mTooltip;
// The preview currently marked as active in the taskbar. nullptr if no
// preview is active (some other window is).
static TaskbarPreview* sActivePreview;
};
/*
* Callback object TaskbarPreview hands to preview controllers when we
* request async thumbnail or live preview images. Controllers invoke
* this interface once they have aquired the requested image.
*/
class TaskbarPreviewCallback : public nsITaskbarPreviewCallback {
public:
TaskbarPreviewCallback() : mIsThumbnail(true) {}
NS_DECL_ISUPPORTS
NS_DECL_NSITASKBARPREVIEWCALLBACK
void SetPreview(TaskbarPreview* aPreview) { mPreview = aPreview; }
void SetIsPreview() { mIsThumbnail = false; }
protected:
virtual ~TaskbarPreviewCallback() {}
private:
RefPtr<TaskbarPreview> mPreview;
bool mIsThumbnail;
};
} // namespace widget
} // namespace mozilla
#endif /* __mozilla_widget_TaskbarPreview_h__ */