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21 
22 
23 
24 #ifndef SD_UPDATE_LOCK_MANAGER_HXX
25 #define SD_UPDATE_LOCK_MANAGER_HXX
26 
27 #include <memory>
28 
29 namespace sd {
30 
31 class ViewShellBase;
32 
33 /** Manage update locks of ViewShellBase objects.
34     A ViewShellBase object is locked while views are switched in order to
35     avoid unnecessary repaints of views and object bars.
36     Locking a ViewShellBase locks the frame::XLayoutManager and prevents
37     Activate() and Deactivate() calls at ViewShell objects being processed.
38 
39     The main responsibility of this class is find the right moment to unlock
40     the managed ViewShellBase object: Only Lock() has to be called from the
41     outside (usually from PaneManager).  Unlock() is called by this class
42     itself.  When all else fails it has a timer that calls Unlock()
43     eventually.
44 */
45 class UpdateLockManager
46 {
47 public:
48     /** The newly created instance supports locking for the specified
49         ViewShellBase object by default.  Call Disable() for Lock() and
50         Unlock() calls being ignored.
51     */
52     UpdateLockManager (ViewShellBase& rBase);
53     ~UpdateLockManager (void);
54 
55     /** For e.g. the PresentationViewShellBase locking is not necessary and
56         does lead to problems.  This method lets Lock() and Unlock() calls
57         be ignored and thus turns locking essentially off.
58     */
59     void Disable (void);
60 
61     /** Lock some UI updates.  For every call to this method a call to
62         Unlock() is required to really unlock.
63     */
64     void Lock (void);
65 
66     /** When called as many times as Lock() has been called before then the
67         ViewShellBase object is unlocked.
68     */
69     void Unlock (void);
70 
71     /** Return whether the ViewShellBase object is locked.  When locking is
72         disabled, i.e. Disable() has been called before, then this method
73         always returns <FALSE/>.
74     */
75     bool IsLocked (void) const;
76 
77 private:
78     class Implementation;
79     Implementation* mpImpl;
80 
81     UpdateLockManager (const UpdateLockManager&); // Not supported.
82     UpdateLockManager& operator= (const UpdateLockManager&); // Not supported.
83 };
84 
85 } // end of namespace sd
86 
87 #endif
88 
89