events: Introduce PlatformEventDispatcher and PlatformEventSource.

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 "base/memory/scoped_ptr.h"
+#include "ui/events/events_export.h"
+#include "ui/events/platform/platform_event_source.h"
+#include "ui/gfx/x/x11_types.h"
+
+typedef struct _GPollFD GPollFD;
+typedef struct _GSource GSource;
+typedef union _XEvent XEvent;
+typedef unsigned long XID;
+
+namespace ui {
+
+// A PlatformEventSource implementation for reading events from X11 server and
+// dispatching the events to the appropriate dispatcher.
+class EVENTS_EXPORT X11EventSource : public PlatformEventSource {
+ public:
+  explicit X11EventSource(XDisplay* display);
+  virtual ~X11EventSource();
+
+  static X11EventSource* GetInstance();
+
+  // Called by the glib source dispatch function. 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);
+
+ private:
+  // Initializes the glib event source for X.
+  void InitXSource();
+
+  // PlatformEventSource:
+  virtual uint32_t DispatchEvent(XEvent* xevent) OVERRIDE;
+
+  // The connection to the X11 server used to receive the events.
+  XDisplay* display_;
+
+  // The GLib event source for X events.
+  GSource* x_source_;
+
+  // The poll attached to |x_source_|.
+  scoped_ptr<GPollFD> x_poll_;
+
+  DISALLOW_COPY_AND_ASSIGN(X11EventSource);
+};
+
+}  // namespace ui
+
+#endif  // UI_EVENTS_PLATFORM_X11_X11_EVENT_SOURCE_H_