X11: Add window cache

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 <xcb/xcb.h>
 
+#include <list>
 #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;
@@ skipping 13 matching lines @@
   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:
+  class EVENTS_EXPORT Request {
+   public:
+    ~Request();
+
+    virtual void OnReply(xcb_generic_reply_t* reply,
+                         xcb_generic_error_t* error) = 0;
+
+    uint32_t sequence() { return sequence_; }
+
+   protected:
+    Request(uint32_t sequence);
+
+    uint32_t sequence_;
+
+    // State necessary for discarding.  Set during
+    // X11EventSource::EnqueueRequest.
+    std::list<std::unique_ptr<Request>>::iterator it_;
+
+   private:
+    friend class X11EventSource;
+  };
+
   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();
@@ skipping 16 matching lines @@
 
   void BlockUntilWindowUnmapped(XID window);
 
   XDisplay* display() { return display_; }
 
   // Returns the timestamp of the event currently being dispatched.  Falls back
   // on GetCurrentServerTime() if there's no event being dispatched, or if the
   // current event does not have a timestamp.
   Time GetTimestamp();
 
+  // Takes ownership of |request|.
+  void EnqueueRequest(Request* request);
+
+  void DiscardRequest(Request* request);
+
   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);
 
   // Explicitly asks the X11 server for the current timestamp, and updates
   // |last_seen_server_time_| with this value.
   Time GetCurrentServerTime();
 
+  bool HasNextReply();
+  bool HasNextEvent();
+  uint32_t NextReplySequence();
+  uint32_t NextEventSequence();
+  void ProcessNextReply();
+  void ProcessNextEvent();
+
  private:
+  friend class TestX11EventSource;
   static X11EventSource* instance_;
 
   X11EventSourceDelegate* delegate_;
 
   // The connection to the X11 server used to receive the events.
   XDisplay* display_;
+  xcb_connection_t* connection_;
 
   // The timestamp of the event being dispatched.
   Time event_timestamp_;
 
   // State necessary for UpdateLastSeenServerTime
   bool dummy_initialized_;
   XWindow dummy_window_;
   XAtom dummy_atom_;
 
+  // Outstanding requests that should be serviced.
+  std::list<std::unique_ptr<Request>> request_queue_;
+
+  // For HasNextReply();
+  void* next_reply_;
+  xcb_generic_error_t* next_error_;
+
   // 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_