gecko-dev/dom/base/Dispatcher.h

92 строки
2.7 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/. */
#ifndef mozilla_dom_Dispatcher_h
#define mozilla_dom_Dispatcher_h
#include "mozilla/AlreadyAddRefed.h"
#include "nsISupports.h"
class nsIEventTarget;
class nsIRunnable;
namespace mozilla {
namespace dom {
class TabGroup;
class DocGroup;
enum class TaskCategory {
// User input (clicks, keypresses, etc.)
UI,
// Data from the network
Network,
// setTimeout, setInterval
Timer,
// Runnables posted from a worker to the main thread
Worker,
// requestIdleCallback
IdleCallback,
// Vsync notifications
RefreshDriver,
// Most DOM events (postMessage, media, plugins)
Other,
Count
};
// This trait should be attached to classes like nsIGlobalObject and nsIDocument
// that have a DocGroup or TabGroup attached to them. The methods here should
// delegate to the DocGroup or TabGroup. We can't use the Dispatcher class
// directly because it inherits from nsISupports.
class DispatcherTrait {
public:
// This method may or may not be safe off of the main thread. For nsIDocument
// it is safe. For nsIGlobalWindow it is not safe.
virtual nsresult Dispatch(const char* aName,
TaskCategory aCategory,
already_AddRefed<nsIRunnable>&& aRunnable);
// This method may or may not be safe off of the main thread. For nsIDocument
// it is safe. For nsIGlobalWindow it is not safe. The nsIEventTarget can
// always be used off the main thread.
virtual nsIEventTarget* EventTargetFor(TaskCategory aCategory) const;
};
// Base class for DocGroup and TabGroup.
class Dispatcher : public nsISupports {
public:
// This method is always safe to call off the main thread.
virtual nsresult Dispatch(const char* aName,
TaskCategory aCategory,
already_AddRefed<nsIRunnable>&& aRunnable) = 0;
// This method is always safe to call off the main thread. The nsIEventTarget
// can always be used off the main thread.
virtual nsIEventTarget* EventTargetFor(TaskCategory aCategory) const = 0;
// These methods perform a safe cast. They return null if |this| is not of the
// requested type.
virtual TabGroup* AsTabGroup() { return nullptr; }
protected:
virtual already_AddRefed<nsIEventTarget>
CreateEventTargetFor(TaskCategory aCategory);
static Dispatcher* FromEventTarget(nsIEventTarget* aEventTarget);
};
} // namespace dom
} // namespace mozilla
#endif // mozilla_dom_Dispatcher_h