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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef BASE_MESSAGE_LOOP_MESSAGE_PUMP_X11_H
      6 #define BASE_MESSAGE_LOOP_MESSAGE_PUMP_X11_H
      7 
      8 #include <bitset>
      9 #include <map>
     10 
     11 #include "base/memory/scoped_ptr.h"
     12 #include "base/message_loop/message_pump.h"
     13 #include "base/message_loop/message_pump_dispatcher.h"
     14 #include "base/message_loop/message_pump_glib.h"
     15 #include "base/message_loop/message_pump_observer.h"
     16 #include "base/observer_list.h"
     17 
     18 // It would be nice to include the X11 headers here so that we use Window
     19 // instead of its typedef of unsigned long, but we can't because everything in
     20 // chrome includes us through base/message_loop/message_loop.h, and X11's crappy
     21 // #define heavy headers muck up half of chrome.
     22 
     23 typedef struct _GPollFD GPollFD;
     24 typedef struct _GSource GSource;
     25 typedef struct _XDisplay Display;
     26 
     27 namespace base {
     28 
     29 // This class implements a message-pump for dispatching X events.
     30 //
     31 // If there's a current dispatcher given through RunWithDispatcher(), that
     32 // dispatcher receives events. Otherwise, we route to messages to dispatchers
     33 // who have subscribed to messages from a specific X11 window.
     34 class BASE_EXPORT MessagePumpX11 : public MessagePumpGlib,
     35                                    public MessagePumpDispatcher {
     36  public:
     37   MessagePumpX11();
     38   virtual ~MessagePumpX11();
     39 
     40   // Returns default X Display.
     41   static Display* GetDefaultXDisplay();
     42 
     43   // Returns the UI or GPU message pump.
     44   static MessagePumpX11* Current();
     45 
     46   // Adds/Removes |dispatcher| for the |xid|. This will route all messages from
     47   // the window |xid| to |dispatcher.
     48   void AddDispatcherForWindow(MessagePumpDispatcher* dispatcher,
     49                               unsigned long xid);
     50   void RemoveDispatcherForWindow(unsigned long xid);
     51 
     52   // Adds/Removes |dispatcher| to receive all events sent to the X root
     53   // window. A root window can have multiple dispatchers, and events on root
     54   // windows will be dispatched to all.
     55   void AddDispatcherForRootWindow(MessagePumpDispatcher* dispatcher);
     56   void RemoveDispatcherForRootWindow(MessagePumpDispatcher* dispatcher);
     57 
     58   // Adds an Observer, which will start receiving notifications immediately.
     59   void AddObserver(MessagePumpObserver* observer);
     60 
     61   // Removes an Observer.  It is safe to call this method while an Observer is
     62   // receiving a notification callback.
     63   void RemoveObserver(MessagePumpObserver* observer);
     64 
     65   // Internal function. Called by the glib source dispatch function. Processes
     66   // all available X events.
     67   bool DispatchXEvents();
     68 
     69   // Blocks on the X11 event queue until we receive notification from the
     70   // xserver that |w| has been mapped; StructureNotifyMask events on |w| are
     71   // pulled out from the queue and dispatched out of order.
     72   //
     73   // For those that know X11, this is really a wrapper around XWindowEvent
     74   // which still makes sure the preempted event is dispatched instead of
     75   // dropped on the floor. This method exists because mapping a window is
     76   // asynchronous (and we receive an XEvent when mapped), while there are also
     77   // functions which require a mapped window.
     78   void BlockUntilWindowMapped(unsigned long xid);
     79 
     80  private:
     81   typedef std::map<unsigned long, MessagePumpDispatcher*> DispatchersMap;
     82 
     83   // Initializes the glib event source for X.
     84   void InitXSource();
     85 
     86   // Dispatches the XEvent and returns true if we should exit the current loop
     87   // of message processing.
     88   bool ProcessXEvent(MessagePumpDispatcher* dispatcher, XEvent* event);
     89 
     90   // Sends the event to the observers. If an observer returns true, then it does
     91   // not send the event to any other observers and returns true. Returns false
     92   // if no observer returns true.
     93   bool WillProcessXEvent(XEvent* xevent);
     94   void DidProcessXEvent(XEvent* xevent);
     95 
     96   // Returns the Dispatcher based on the event's target window.
     97   MessagePumpDispatcher* GetDispatcherForXEvent(const NativeEvent& xev) const;
     98 
     99   ObserverList<MessagePumpObserver>& observers() { return observers_; }
    100 
    101   // Overridden from MessagePumpDispatcher:
    102   virtual bool Dispatch(const NativeEvent& event) OVERRIDE;
    103 
    104   // The event source for X events.
    105   GSource* x_source_;
    106 
    107   // The poll attached to |x_source_|.
    108   scoped_ptr<GPollFD> x_poll_;
    109 
    110   DispatchersMap dispatchers_;
    111 
    112   // Dispatch calls can cause addition of new dispatchers as we iterate
    113   // through them. Use ObserverList to ensure the iterator remains valid across
    114   // additions.
    115   ObserverList<MessagePumpDispatcher> root_window_dispatchers_;
    116 
    117   // List of observers.
    118   ObserverList<MessagePumpObserver> observers_;
    119 
    120   unsigned long x_root_window_;
    121 
    122   DISALLOW_COPY_AND_ASSIGN(MessagePumpX11);
    123 };
    124 
    125 #if !defined(TOOLKIT_GTK)
    126 typedef MessagePumpX11 MessagePumpForUI;
    127 #endif
    128 
    129 }  // namespace base
    130 
    131 #endif  // BASE_MESSAGE_LOOP_MESSAGE_PUMP_X11_H
    132