src/plugin.h

   1 /* ncmpc (Ncurses MPD Client)
   2  * (c) 2004-2009 The Music Player Daemon Project
   3  * Project homepage: http://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
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18 */
  19
  20 #ifndef PLUGIN_H
  21 #define PLUGIN_H
  22
  23 #include <glib.h>
  24 #include <stdbool.h>
  25
  26 /**
  27  * A list of registered plugins.
  28  */
  29 struct plugin_list {
  30         GPtrArray *plugins;
  31 };
  32
  33 /**
  34  * When a plugin cycle is finished, this function is called.  In any
  35  * case, plugin_stop() has to be called to free all memory.
  36  *
  37  * @param result the plugin's output (stdout) on success; summary of all error
  38  * messages on failure as determined by success
  39  * @param success result of the plugin cycle; true if result is meaningful
  40  * output, false if result contains error messages
  41  * @param data the caller defined pointer passed to plugin_run()
  42  */
  43 typedef void (*plugin_callback_t)(const GString *result, const bool success,
  44                                   void *data);
  45
  46 /**
  47  * This object represents a cycle through all available plugins, until
  48  * a plugin returns a positive result.
  49  */
  50 struct plugin_cycle;
  51
  52 /**
  53  * Initialize an empty plugin_list structure.
  54  */
  55 static inline void
  56 plugin_list_init(struct plugin_list *list)
  57 {
  58         list->plugins = g_ptr_array_new();
  59 }
  60
  61 /**
  62  * Load all plugins (executables) in a directory.
  63  */
  64 bool
  65 plugin_list_load_directory(struct plugin_list *list, const char *path);
  66
  67 /**
  68  * Frees all memory held by the plugin_list object (but not the
  69  * pointer itself).
  70  */
  71 void plugin_list_deinit(struct plugin_list *list);
  72
  73 /**
  74  * Run plugins in this list, until one returns success (or until the
  75  * plugin list is exhausted).
  76  *
  77  * @param list the plugin list
  78  * @param args NULL terminated command line arguments passed to the
  79  * plugin programs
  80  * @param callback the callback function which will be called when a
  81  * result is available
  82  * @param callback_data caller defined pointer which is passed to the
  83  * callback function
  84  */
  85 struct plugin_cycle *
  86 plugin_run(struct plugin_list *list, const char *const*args,
  87            plugin_callback_t callback, void *callback_data);
  88
  89 /**
  90  * Stops the plugin cycle and frees resources.  This can be called to
  91  * abort the current cycle, or after the plugin_callback_t has been
  92  * invoked.
  93  */
  94 void
  95 plugin_stop(struct plugin_cycle *invocation);
  96
  97 #endif