forked from mirrors/gecko-dev
371b0d83fc
Implement a mochitest confirming the stability of Firefox when the file-picker crashes (patterned loosely off the existing geolocation crash tests). Differential Revision: https://phabricator.services.mozilla.com/D184723
117 lines
3.6 KiB
C++
117 lines
3.6 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/. */
|
|
|
|
#ifndef WinHandleWatcher_h__
|
|
#define WinHandleWatcher_h__
|
|
|
|
#include <minwindef.h>
|
|
|
|
#include "mozilla/AlreadyAddRefed.h"
|
|
#include "mozilla/RefPtr.h"
|
|
#include "mozilla/UniquePtr.h"
|
|
|
|
#include "nsIEventTarget.h"
|
|
#include "nsIRunnable.h"
|
|
#include "nsIThread.h"
|
|
#include "nsThreadUtils.h"
|
|
|
|
namespace mozilla {
|
|
///////////////////////////////////////////////////////////////////////
|
|
// HandleWatcher
|
|
//
|
|
// Enqueues a task onto an event target when a watched Win32 synchronization
|
|
// object [1] enters the signaled state.
|
|
//
|
|
// The HandleWatcher must be stopped before either it or the synchronization
|
|
// object is destroyed.
|
|
//
|
|
//////
|
|
//
|
|
// Example of use:
|
|
//
|
|
// ```
|
|
// class MyClass {
|
|
// /* ... */
|
|
//
|
|
// HANDLE CreateThing();
|
|
// void OnComplete();
|
|
// public:
|
|
// void Fire() {
|
|
// mHandle.set(CreateThing());
|
|
// mWatcher.Watch(
|
|
// mHandle.get(), NS_GetCurrentThread(), // (or any other thread)
|
|
// NS_NewRunnableFunction("OnComplete", [this] { OnComplete(); }));
|
|
// }
|
|
//
|
|
// ~MyClass() { mWatcher.Stop(); }
|
|
//
|
|
// HandleWatcher mWatcher;
|
|
// HandlePtr mHandle; // calls ::CloseHandle() on destruction
|
|
// };
|
|
// ```
|
|
//
|
|
// Note: this example demonstrates why an explicit `Stop()` is necessary in
|
|
// MyClass's destructor. Without it, the `HandlePtr` would destroy the HANDLE --
|
|
// and possibly whatever other data `OnComplete()` depends on -- before the
|
|
// watch was stopped!
|
|
//
|
|
// Rather than make code correctness silently dependent on member object order,
|
|
// we require that HandleWatcher already be stopped at its destruction time.
|
|
// (This does not guarantee correctness, as the task may still reference a
|
|
// partially-destroyed transitive owner; but, short of RIIR, a guarantee of
|
|
// correctness is probably not possible here.)
|
|
//
|
|
//////
|
|
//
|
|
// [1]https://learn.microsoft.com/en-us/windows/win32/sync/synchronization-objects
|
|
class HandleWatcher {
|
|
public:
|
|
class Impl;
|
|
|
|
HandleWatcher();
|
|
~HandleWatcher();
|
|
|
|
HandleWatcher(HandleWatcher const&) = delete;
|
|
HandleWatcher& operator=(HandleWatcher const&) = delete;
|
|
|
|
HandleWatcher(HandleWatcher&&) noexcept;
|
|
HandleWatcher& operator=(HandleWatcher&&) noexcept;
|
|
|
|
// Watches the given Win32 HANDLE, which must be a synchronization object. As
|
|
// soon as the HANDLE is signaled, posts `aRunnable` to `aTarget`.
|
|
//
|
|
// `aHandle` is merely borrowed for the duration of the watch: the
|
|
// HandleWatcher does not attempt to close it, and its lifetime must exceed
|
|
// that of the watch.
|
|
//
|
|
// If the watch is stopped for any reason other than completion, `aRunnable`
|
|
// is released immediately, on the same thread from which the Watch was
|
|
// stopped.
|
|
//
|
|
// The watch is stopped when any of the following occurs:
|
|
// * `Stop()` is called.
|
|
// * `Watch()` is called again, even without an intervening `Stop()`.
|
|
// * This object is destroyed.
|
|
// * `aTarget` shuts down.
|
|
// * `aHandle` becomes signaled.
|
|
//
|
|
void Watch(HANDLE aHandle, nsIEventTarget* aTarget,
|
|
already_AddRefed<nsIRunnable> aRunnable);
|
|
|
|
// Cancels the current watch, if any.
|
|
//
|
|
// Idempotent. Thread-safe with respect to other calls of `Stop()`.
|
|
void Stop();
|
|
|
|
// Potentially racy. Only intended for tests.
|
|
bool IsStopped();
|
|
|
|
private:
|
|
RefPtr<Impl> mImpl;
|
|
};
|
|
} // namespace mozilla
|
|
|
|
#endif // WinHandleWatcher_h__
|