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73
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1 #ifndef __OBSERVER_H_
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2 #define __OBSERVER_H_
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3
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4 #include "tools.h"
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5
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6 typedef struct _event event_t;
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7 typedef struct _observer observer_t;
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8 typedef struct _subject subject_t;
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9 typedef struct _mouse_event mouse_event_t;
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10 typedef struct _ob_factory ob_factory_t;
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11 typedef void (*evt_handler)(event_t *event, void *arg);
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12
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13 struct _event {
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14 int type;
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15 subject_t *tgt, *cur_tgt;
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16 };
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17
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78
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18 /*! \brief Observer of observer pattern.
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19 *
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20 * A target for receiving events.
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21 */
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73
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22 struct _observer {
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23 evt_handler hdr;
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24 void *arg;
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25 observer_t *next;
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26 };
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27
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78
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28 /*! \brief Subject of observer pattern.
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29 *
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30 * Observer is a pattern to decouple caller and callee,
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31 * especial for multiple callee.
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32 * \see http://en.wikipedia.org/wiki/Observer_pattern
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33 */
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73
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34 struct _subject {
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78
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35 int obj_type; /*!< type of object (a.k.a. OBJT_*). */
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36 void *obj; /*!< the object this subject for. */
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73
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37 int flags;
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38 STAILQ(observer_t) observers;
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39 };
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78
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40 /*! \brief Flag that make a subject to propagate events to parents. */
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73
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41 #define SUBF_STOP_PROPAGATE 0x1
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42
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43 enum {OBJT_GEO, OBJT_COORD};
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44
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45 struct _mouse_event {
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46 event_t event;
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47 int x, y;
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78
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48 unsigned int but_state;
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49 unsigned int button;
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73
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50 };
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51
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76
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52 #define MOUSE_BUT1 0x1
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53 #define MOUSE_BUT2 0x2
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54 #define MOUSE_BUT3 0x4
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55
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73
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56 /*! \brief Observer factory.
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57 *
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58 * It provides functions for allocation of subject and observer objects,
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59 * and strategy function for getting the subject of parent coord object.
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60 */
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61 struct _ob_factory {
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62 subject_t *(*subject_alloc)(ob_factory_t *factory);
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63 void (*subject_free)(ob_factory_t *factory, subject_t *subject);
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64 observer_t *(*observer_alloc)(ob_factory_t *factory);
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65 void (*observer_free)(ob_factory_t *factory, observer_t *observer);
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66 /*! This is a strategy function to get subjects of parents. */
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67 subject_t *(*get_parent_subject)(ob_factory_t *factory,
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68 subject_t *cur_subject);
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69 };
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70
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71 enum {EVT_MOUSE_OVER, EVT_MOUSE_OUT, EVT_MOUSE_MOVE,
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72 EVT_MOUSE_BUT_PRESS, EVT_MOUSE_BUT_RELEASE};
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73
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74 extern subject_t *subject_new(ob_factory_t *factory,
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75 void *obj, int obj_type);
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76 extern void subject_free(ob_factory_t *factory, subject_t *subject);
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77 extern void subject_notify(ob_factory_t *factory,
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78 subject_t *subject, event_t *evt);
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79 extern observer_t *subject_add_observer(ob_factory_t *factory,
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80 subject_t *subject,
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81 evt_handler hdr, void *arg);
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82 extern void subject_remove_observer(ob_factory_t *factory,
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83 subject_t *subject,
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84 observer_t *observer);
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85
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86
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87 #endif /* __OBSERVER_H_ */
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