1 /**********************************************************************
2  *
3  * GEOS - Geometry Engine Open Source
4  * http://geos.osgeo.org
5  *
6  * Copyright (C) 2012 Sandro Santilli <strk@kbt.io>
7  *
8  * This is free software; you can redistribute and/or modify it under
9  * the terms of the GNU Lesser General Public Licence as published
10  * by the Free Software Foundation.
11  * See the COPYING file for more information.
12  *
13  **********************************************************************/
14 
15 #ifndef GEOS_UTIL_INTERRUPT_H
16 #define GEOS_UTIL_INTERRUPT_H
17 
18 #include <geos/export.h>
19 
20 namespace geos {
21 namespace util { // geos::util
22 
23 #define GEOS_CHECK_FOR_INTERRUPTS() geos::util::Interrupt::process()
24 
25 /** \brief Used to manage interruption requests and callbacks. */
26 class GEOS_DLL Interrupt {
27 
28 public:
29 
30     typedef void (Callback)(void);
31 
32     /**
33      * Request interruption of operations
34      *
35      * Operations will be terminated by a GEOSInterrupt
36      * exception at first occasion.
37      */
38     static void request();
39 
40     /** Cancel a pending interruption request */
41     static void cancel();
42 
43     /** Check if an interruption request is pending */
44     static bool check();
45 
46     /** \brief
47      * Register a callback that will be invoked
48      * before checking for interruption requests.
49      *
50      * NOTE that interruption request checking may happen
51      * frequently so any callback would better be quick.
52      *
53      * The callback can be used to call Interrupt::request()
54      *
55      */
56     static Callback* registerCallback(Callback* cb);
57 
58     /**
59      * Invoke the callback, if any. Process pending interruption, if any.
60      *
61      */
62     static void process();
63 
64     /* Perform the actual interruption (simply throw an exception) */
65     static void interrupt();
66 
67 };
68 
69 
70 } // namespace geos::util
71 } // namespace geos
72 
73 
74 #endif // GEOS_UTIL_INTERRUPT_H
75