1 /*
2 * (c) 2004-2008 The Music Player Daemon Project
3 * http://www.musicpd.org/
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17 */
19 #ifndef PLUGIN_H
20 #define PLUGIN_H
22 #include <glib.h>
23 #include <stdbool.h>
25 /**
26 * A list of registered plugins.
27 */
28 struct plugin_list {
29 GPtrArray *plugins;
30 };
32 /**
33 * When a plugin cycle is finished, this function is called. In any
34 * case, plugin_stop() has to be called to free all memory.
35 *
36 * @param result the plugin's output (stdout) on success; NULL on failure
37 * @param data the caller defined pointer passed to plugin_run()
38 */
39 typedef void (*plugin_callback_t)(const GString *result, void *data);
41 /**
42 * This object represents a cycle through all available plugins, until
43 * a plugin returns a positive result.
44 */
45 struct plugin_cycle;
47 /**
48 * Initialize an empty plugin_list structure.
49 */
50 static inline void
51 plugin_list_init(struct plugin_list *list)
52 {
53 list->plugins = g_ptr_array_new();
54 }
56 /**
57 * Load all plugins (executables) in a directory.
58 */
59 bool
60 plugin_list_load_directory(struct plugin_list *list, const char *path);
62 /**
63 * Frees all memory held by the plugin_list object (but not the
64 * pointer itself).
65 */
66 void plugin_list_deinit(struct plugin_list *list);
68 /**
69 * Run plugins in this list, until one returns success (or until the
70 * plugin list is exhausted).
71 *
72 * @param list the plugin list
73 * @param args NULL terminated command line arguments passed to the
74 * plugin programs
75 * @param callback the callback function which will be called when a
76 * result is available
77 * @param callback_data caller defined pointer which is passed to the
78 * callback function
79 */
80 struct plugin_cycle *
81 plugin_run(struct plugin_list *list, const char *const*args,
82 plugin_callback_t callback, void *callback_data);
84 /**
85 * Stops the plugin cycle and frees resources. This can be called to
86 * abort the current cycle, or after the plugin_callback_t has been
87 * invoked.
88 */
89 void
90 plugin_stop(struct plugin_cycle *invocation);
92 #endif