src/modules/modules.h

   1 /*****************************************************************************
   2  * modules.h : Module management functions.
   3  *****************************************************************************
   4  * Copyright (C) 2001-2016 VLC authors and VideoLAN
   5  * $Id$
   6  *
   7  * Authors: Samuel Hocevar <sam@zoy.org>
   8  *
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU Lesser General Public License as published by
  11  * the Free Software Foundation; either version 2.1 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  17  * GNU Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public License
  20  * along with this program; if not, write to the Free Software Foundation,
  21  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  22  *****************************************************************************/
  23
  24 #ifndef LIBVLC_MODULES_H
  25 # define LIBVLC_MODULES_H 1
  26
  27 # include <stdatomic.h>
  28
  29 /** VLC plugin */
  30 typedef struct vlc_plugin_t
  31 {
  32     struct vlc_plugin_t *next;
  33     module_t *module;
  34     unsigned modules_count;
  35
  36     const char *textdomain; /**< gettext domain (or NULL) */
  37
  38     /**
  39      * Variables set by the module to store its config options
  40      */
  41     struct
  42     {
  43         module_config_t *items; /**< Table of configuration parameters */
  44         size_t size; /**< Size of items table */
  45         size_t count; /**< Number of configuration items */
  46         size_t booleans; /**< Number of booleal config items */
  47     } conf;
  48
  49 #ifdef HAVE_DYNAMIC_PLUGINS
  50     atomic_bool loaded; /**< Whether the plug-in is mapped in memory */
  51     bool unloadable; /**< Whether the plug-in can be unloaded safely */
  52     void *handle; /**< Run-time linker handle (if loaded) */
  53     char *abspath; /**< Absolute path */
  54
  55     char *path; /**< Relative path (within plug-in directory) */
  56     int64_t mtime; /**< Last modification time */
  57     uint64_t size; /**< File size */
  58 #endif
  59 } vlc_plugin_t;
  60
  61 /**
  62  * List of all plug-ins.
  63  */
  64 extern struct vlc_plugin_t *vlc_plugins;
  65
  66 #define MODULE_SHORTCUT_MAX 20
  67
  68 /** Plugin entry point prototype */
  69 typedef int (*vlc_plugin_cb) (int (*)(void *, void *, int, ...), void *);
  70
  71 /** Core module */
  72 int vlc_entry__core (int (*)(void *, void *, int, ...), void *);
  73
  74 /**
  75  * Internal module descriptor
  76  */
  77 struct module_t
  78 {
  79     vlc_plugin_t *plugin; /**< Plug-in/library containing the module */
  80     module_t   *next;
  81
  82     /** Shortcuts to the module */
  83     unsigned    i_shortcuts;
  84     const char **pp_shortcuts;
  85
  86     /*
  87      * Variables set by the module to identify itself
  88      */
  89     const char *psz_shortname;                              /**< Module name */
  90     const char *psz_longname;                   /**< Module descriptive name */
  91     const char *psz_help;        /**< Long help string for "special" modules */
  92
  93     const char *psz_capability;                              /**< Capability */
  94     int      i_score;                          /**< Score for the capability */
  95
  96     /* Callbacks */
  97     const char *activate_name;
  98     const char *deactivate_name;
  99     void *pf_activate;
 100     void *pf_deactivate;
 101 };
 102
 103 vlc_plugin_t *vlc_plugin_create(void);
 104 void vlc_plugin_destroy(vlc_plugin_t *);
 105 module_t *vlc_module_create(vlc_plugin_t *);
 106 void vlc_module_destroy (module_t *);
 107
 108 vlc_plugin_t *vlc_plugin_describe(vlc_plugin_cb);
 109 int vlc_plugin_resolve(vlc_plugin_t *, vlc_plugin_cb);
 110
 111 void module_InitBank (void);
 112 size_t module_LoadPlugins( vlc_object_t * );
 113 #define module_LoadPlugins(a) module_LoadPlugins(VLC_OBJECT(a))
 114 void module_EndBank (bool);
 115 int module_Map(vlc_object_t *, vlc_plugin_t *);
 116
 117 ssize_t module_list_cap (module_t ***, const char *);
 118
 119 int vlc_bindtextdomain (const char *);
 120
 121 /* Low-level OS-dependent handler */
 122
 123 /**
 124  * Loads a dynamically linked library.
 125  *
 126  * \param path library file path
 127  * \param lazy whether to resolve the symbols lazily
 128  * \return a module handle on success, or NULL on error.
 129  */
 130 void *vlc_dlopen(const char *path, bool) VLC_USED;
 131
 132 /**
 133  * Unloads a dynamic library.
 134  *
 135  * This function unloads a previously opened dynamically linked library
 136  * using a system dependent method.
 137  * \param handle handle of the library
 138  * \retval 0 on success
 139  * \retval -1 on error (none are defined though)
 140  */
 141 int vlc_dlclose(void *);
 142
 143 /**
 144  * Looks up a symbol from a dynamically loaded library
 145  *
 146  * This function looks for a named symbol within a loaded library.
 147  *
 148  * \param handle handle to the library
 149  * \param name function name
 150  * \return the address of the symbol on success, or NULL on error
 151  *
 152  * \note If the symbol address is NULL, errors cannot be detected. However,
 153  * normal symbols such as function or global variables cannot have NULL as
 154  * their address.
 155  */
 156 void *vlc_dlsym(void *handle, const char *) VLC_USED;
 157
 158 /**
 159  * Formats an error message for vlc_dlopen() or vlc_dlsym().
 160  *
 161  * \return a heap-allocated nul-terminated error string, or NULL.
 162  */
 163 char *vlc_dlerror(void) VLC_USED;
 164
 165 /* Plugins cache */
 166 vlc_plugin_t *vlc_cache_load(vlc_object_t *, const char *, block_t **);
 167 vlc_plugin_t *vlc_cache_lookup(vlc_plugin_t **, const char *relpath);
 168
 169 void CacheSave(vlc_object_t *, const char *, vlc_plugin_t *const *, size_t);
 170
 171 #endif /* !LIBVLC_MODULES_H */