event.h

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/*
 * $Id: event.h,v 1.6 2005/08/31 21:37:33 rmanfredi Exp $
 *
 * Copyright (c) 2002-2003, Richard Eckart
 *
 *----------------------------------------------------------------------
 * This file is part of gtk-gnutella.
 *
 *  gtk-gnutella is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  gtk-gnutella is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with gtk-gnutella; if not, write to the Free Software
 *  Foundation, Inc.:
 *      59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *----------------------------------------------------------------------
 */

#ifndef _event_h_
#define _event_h_

#include "common.h"

#include "tm.h"

typedef enum frequency_type {
    FREQ_SECS,
    FREQ_UPDATES
} frequency_t;

struct subscriber {
    GCallback           cb;
    enum frequency_type f_type;
    guint32             f_interval;
    time_t              last_call;
};

typedef struct event {
    const gchar *name;
    guint32      triggered_count;
    GSList      *subscribers;
} event_t;

struct event *event_new(const gchar *name);

#define event_destroy(evt) G_STMT_START {                          \
    real_event_destroy(evt);                                       \
    G_FREE_NULL(evt);                                              \
} G_STMT_END

void real_event_destroy(struct event *evt);

void event_add_subscriber(
    struct event *evt, GCallback cb, frequency_t t, guint32 interval);
void event_remove_subscriber(struct event *evt, GCallback cb);

guint event_subscriber_count(struct event *evt);
gboolean event_subscriber_active(struct event *evt);

/*
 * T_VETO:   breaks trigger chain as soon as a subscriber returns
 *           a value != 0.
 *
 * T_NORMAL: will call all subscribers in the chain. Use for
 *           callbacks with a void return type.
 */
#define T_VETO(sig, params) if (((sig) vars_.s->cb) params ) break;
#define T_NORMAL(sig, params)   ((sig) vars_.s->cb) params ;

#define event_trigger(ev, callback) G_STMT_START {                          \
    struct {                                                                \
        GSList *sl;                                                         \
        event_t *evt;                                                       \
        struct subscriber *s;                                               \
        time_t now;                                                         \
        gboolean t;                                                         \
    } vars_;                                                                \
                                                                            \
    vars_.evt = (ev);                                                       \
    vars_.now = (time_t) -1;                                                \
    vars_.sl = vars_.evt->subscribers;                                      \
    for (/* NOTHING */; vars_.sl; vars_.sl = g_slist_next(vars_.sl)) {      \
        vars_.s = vars_.sl->data;                                           \
        vars_.t = 0 == vars_.s->f_interval;                                 \
        if (!vars_.t) {                                                     \
            switch (vars_.s->f_type) {                                      \
            case FREQ_UPDATES:                                              \
                vars_.t = 0 == (vars_.evt->triggered_count %                \
                                    vars_.s->f_interval);                   \
                break;                                                      \
            case FREQ_SECS:                                                 \
                if ((time_t) -1 == vars_.now)                               \
                    vars_.now = tm_time();                                  \
                vars_.t = vars_.s->f_interval <=                            \
                        (guint32) delta_time(vars_.now, vars_.s->last_call);\
                break;                                                      \
            default:                                                        \
                g_assert_not_reached();                                     \
            }                                                               \
        }                                                                   \
        if (vars_.t) {                                                      \
            if (FREQ_SECS == vars_.s->f_type) {                             \
                if ((time_t) -1 == vars_.now)                               \
                    vars_.now = tm_time();                                  \
                vars_.s->last_call = vars_.now;                             \
            }                                                               \
            callback                                                        \
        }                                                                   \
    }                                                                       \
    vars_.evt->triggered_count++;                                           \
} G_STMT_END

struct event_table {
    GHashTable *events;
};

struct event_table *event_table_new(void);

#define event_table_destroy(t) G_STMT_START {                      \
    real_event_table_destroy(t);                                   \
    G_FREE_NULL(t);                                                \
} G_STMT_END
void real_event_table_destroy(struct event_table *t, gboolean cleanup);


void event_table_add_event(struct event_table *t, struct event *evt);
void event_table_remove_event(struct event_table *t, struct event *evt);
void event_table_remove_all(struct event_table *t);

#endif  /* _event_h_ */

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