ui/events/platform/x11/x11_event_source.h

// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_EVENTS_PLATFORM_X11_X11_EVENT_SOURCE_H_
#define UI_EVENTS_PLATFORM_X11_X11_EVENT_SOURCE_H_

#include <stdint.h>

#include <memory>

#include "base/macros.h"
#include "ui/events/events_export.h"
#include "ui/gfx/x/x11_types.h"

using Time = unsigned long;
using XEvent = union _XEvent;
using XID = unsigned long;
using XWindow = unsigned long;

namespace ui {

class X11HotplugEventHandler;

// Responsible for notifying X11EventSource when new XEvents are available and
// processing/dispatching XEvents. Implementations will likely be a
// PlatformEventSource.
class X11EventSourceDelegate {
 public:
  X11EventSourceDelegate() = default;

  // Processes (if necessary) and handles dispatching XEvents.
  virtual void ProcessXEvent(XEvent* xevent) = 0;

 private:
  DISALLOW_COPY_AND_ASSIGN(X11EventSourceDelegate);
};

// Receives X11 events and sends them to X11EventSourceDelegate. Handles
// receiving, pre-process and post-processing XEvents.
class EVENTS_EXPORT X11EventSource {
 public:
  X11EventSource(X11EventSourceDelegate* delegate, XDisplay* display);
  ~X11EventSource();

  static bool HasInstance();

  static X11EventSource* GetInstance();

  // Called when there is a new XEvent available. Processes all (if any)
  // available X events.
  void DispatchXEvents();

  // Blocks on the X11 event queue until we receive notification from the
  // xserver that |w| has been mapped; StructureNotifyMask events on |w| are
  // pulled out from the queue and dispatched out of order.
  //
  // For those that know X11, this is really a wrapper around XWindowEvent
  // which still makes sure the preempted event is dispatched instead of
  // dropped on the floor. This method exists because mapping a window is
  // asynchronous (and we receive an XEvent when mapped), while there are also
  // functions which require a mapped window.
  void BlockUntilWindowMapped(XID window);

  void BlockUntilWindowUnmapped(XID window);

  XDisplay* display() { return display_; }
  Time last_seen_server_time() const { return last_seen_server_time_; }

  // Explicitly asks the X11 server for the current timestamp, and updates
  // |last_seen_server_time| with this value.
  Time UpdateLastSeenServerTime();

  void StopCurrentEventStream();
  void OnDispatcherListChanged();

 protected:
  // Extracts cookie data from |xevent| if it's of GenericType, and dispatches
  // the event. This function also frees up the cookie data after dispatch is
  // complete.
  void ExtractCookieDataDispatchEvent(XEvent* xevent);

  // Handles updates after event has been dispatched.
  void PostDispatchEvent(XEvent* xevent);

  // Block until receiving a structure notify event of |type| on |window|.
  // Dispatch all encountered events prior to the one we're blocking on.
  void BlockOnWindowStructureEvent(XID window, int type);

 private:
  static X11EventSource* instance_;

  X11EventSourceDelegate* delegate_;

  // The connection to the X11 server used to receive the events.
  XDisplay* display_;

  // The last timestamp seen in an XEvent.
  Time last_seen_server_time_;

  // State necessary for UpdateLastSeenServerTime
  bool dummy_initialized_;
  XWindow dummy_window_;
  XAtom dummy_atom_;

  // Keeps track of whether this source should continue to dispatch all the
  // available events.
  bool continue_stream_ = true;

  std::unique_ptr<X11HotplugEventHandler> hotplug_event_handler_;

  DISALLOW_COPY_AND_ASSIGN(X11EventSource);
};

}  // namespace ui

#endif  // UI_EVENTS_PLATFORM_X11_X11_EVENT_SOURCE_H_