1 /* GIO - GLib Input, Output and Streaming Library
3 * Copyright (C) 2006-2007 Red Hat, Inc.
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
10 * This library 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 GNU
13 * Lesser General Public License for more details.
15 * You should have received a copy of the GNU Lesser General
16 * Public License along with this library; if not, write to the
17 * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
18 * Boston, MA 02111-1307, USA.
20 * Author: Alexander Larsson <alexl@redhat.com>
27 #include "giomodule.h"
28 #include "giomodule-priv.h"
29 #include "gmemorysettingsbackend.h"
30 #include "glocalfilemonitor.h"
31 #include "glocaldirectorymonitor.h"
32 #include "gnativevolumemonitor.h"
35 #include "gdesktopappinfo.h"
37 #include <glib/gstdio.h>
41 * @short_description: Loadable GIO Modules
44 * Provides an interface and default functions for loading and unloading
45 * modules. This is used internally to make GIO extensible, but can also
46 * be used by others to implement module loading.
51 * SECTION:extensionpoints
52 * @short_description: Extension Points
54 * @see_also: <link linkend="extending-gio">Extending GIO</link>
56 * #GIOExtensionPoint provides a mechanism for modules to extend the
57 * functionality of the library or application that loaded it in an
60 * An extension point is identified by a name, and it may optionally
61 * require that any implementation must by of a certain type (or derived
62 * thereof). Use g_io_extension_point_register() to register an
63 * extension point, and g_io_extension_point_set_required_type() to
64 * set a required type.
66 * A module can implement an extension point by specifying the #GType
67 * that implements the functionality. Additionally, each implementation
68 * of an extension point has a name, and a priority. Use
69 * g_io_extension_point_implement() to implement an extension point.
72 * GIOExtensionPoint *ep;
74 * /* Register an extension point */
75 * ep = g_io_extension_point_register ("my-extension-point");
76 * g_io_extension_point_set_required_type (ep, MY_TYPE_EXAMPLE);
80 * /* Implement an extension point */
81 * G_DEFINE_TYPE (MyExampleImpl, my_example_impl, MY_TYPE_EXAMPLE);
82 * g_io_extension_point_implement ("my-extension-point",
83 * my_example_impl_get_type (),
88 * It is up to the code that registered the extension point how
89 * it uses the implementations that have been associated with it.
90 * Depending on the use case, it may use all implementations, or
91 * only the one with the highest priority, or pick a specific
94 * To avoid opening all modules just to find out what extension
95 * points they implement, GIO makes use of a caching mechanism,
96 * see <link linkend="gio-querymodules">gio-querymodules</link>.
97 * You are expected to run this command after installing a
101 GTypeModule parent_instance;
105 gboolean initialized; /* The module was loaded at least once */
107 void (* load) (GIOModule *module);
108 void (* unload) (GIOModule *module);
111 struct _GIOModuleClass
113 GTypeModuleClass parent_class;
117 static void g_io_module_finalize (GObject *object);
118 static gboolean g_io_module_load_module (GTypeModule *gmodule);
119 static void g_io_module_unload_module (GTypeModule *gmodule);
121 struct _GIOExtension {
127 struct _GIOExtensionPoint {
131 GList *lazy_load_modules;
134 static GHashTable *extension_points = NULL;
135 G_LOCK_DEFINE_STATIC(extension_points);
137 G_DEFINE_TYPE (GIOModule, g_io_module, G_TYPE_TYPE_MODULE);
140 g_io_module_class_init (GIOModuleClass *class)
142 GObjectClass *object_class = G_OBJECT_CLASS (class);
143 GTypeModuleClass *type_module_class = G_TYPE_MODULE_CLASS (class);
145 object_class->finalize = g_io_module_finalize;
147 type_module_class->load = g_io_module_load_module;
148 type_module_class->unload = g_io_module_unload_module;
152 g_io_module_init (GIOModule *module)
157 g_io_module_finalize (GObject *object)
159 GIOModule *module = G_IO_MODULE (object);
161 g_free (module->filename);
163 G_OBJECT_CLASS (g_io_module_parent_class)->finalize (object);
167 g_io_module_load_module (GTypeModule *gmodule)
169 GIOModule *module = G_IO_MODULE (gmodule);
171 if (!module->filename)
173 g_warning ("GIOModule path not set");
177 module->library = g_module_open (module->filename, G_MODULE_BIND_LAZY | G_MODULE_BIND_LOCAL);
179 if (!module->library)
181 g_printerr ("%s\n", g_module_error ());
185 /* Make sure that the loaded library contains the required methods */
186 if (! g_module_symbol (module->library,
188 (gpointer) &module->load) ||
189 ! g_module_symbol (module->library,
190 "g_io_module_unload",
191 (gpointer) &module->unload))
193 g_printerr ("%s\n", g_module_error ());
194 g_module_close (module->library);
199 /* Initialize the loaded module */
200 module->load (module);
201 module->initialized = TRUE;
207 g_io_module_unload_module (GTypeModule *gmodule)
209 GIOModule *module = G_IO_MODULE (gmodule);
211 module->unload (module);
213 g_module_close (module->library);
214 module->library = NULL;
217 module->unload = NULL;
222 * @filename: filename of the shared library module.
224 * Creates a new GIOModule that will load the specific
225 * shared library when in use.
227 * Returns: a #GIOModule from given @filename,
231 g_io_module_new (const gchar *filename)
235 g_return_val_if_fail (filename != NULL, NULL);
237 module = g_object_new (G_IO_TYPE_MODULE, NULL);
238 module->filename = g_strdup (filename);
244 is_valid_module_name (const gchar *basename)
246 #if !defined(G_OS_WIN32) && !defined(G_WITH_CYGWIN)
248 g_str_has_prefix (basename, "lib") &&
249 g_str_has_suffix (basename, ".so");
251 return g_str_has_suffix (basename, ".dll");
256 * g_io_modules_scan_all_in_directory:
257 * @dirname: pathname for a directory containing modules to scan.
259 * Scans all the modules in the specified directory, ensuring that
260 * any extension point implemented by a module is registered.
262 * This may not actually load and initialize all the types in each
263 * module, some modules may be lazily loaded and initialized when
264 * an extension point it implementes is used with e.g.
265 * g_io_extension_point_get_extensions() or
266 * g_io_extension_point_get_extension_by_name().
268 * If you need to guarantee that all types are loaded in all the modules,
269 * use g_io_modules_scan_all_in_directory().
274 g_io_modules_scan_all_in_directory (const char *dirname)
284 if (!g_module_supported ())
287 dir = g_dir_open (dirname, 0, NULL);
291 filename = g_build_filename (dirname, "giomodule.cache", NULL);
293 cache = g_hash_table_new_full (g_str_hash, g_str_equal,
294 g_free, (GDestroyNotify)g_strfreev);
297 if (g_stat (filename, &statbuf) == 0 &&
298 g_file_get_contents (filename, &data, NULL, NULL))
303 /* Cache mtime is the time the cache file was created, any file
304 * that has a ctime before this was created then and not modified
305 * since then (userspace can't change ctime). Its possible to change
306 * the ctime forward without changing the file content, by e.g.
307 * chmoding the file, but this is uncommon and will only cause us
308 * to not use the cache so will not cause bugs.
310 cache_mtime = statbuf.st_mtime;
312 lines = g_strsplit (data, "\n", -1);
315 for (i = 0; lines[i] != NULL; i++)
317 char *line = lines[i];
320 char **extension_points;
325 colon = strchr (line, ':');
326 if (colon == NULL || line == colon)
327 continue; /* Invalid line, ignore */
329 *colon = 0; /* terminate filename */
330 file = g_strdup (line);
331 colon++; /* after colon */
333 while (g_ascii_isspace (*colon))
336 extension_points = g_strsplit (colon, ",", -1);
337 g_hash_table_insert (cache, file, extension_points);
342 while ((name = g_dir_read_name (dir)))
344 if (is_valid_module_name (name))
346 GIOExtensionPoint *extension_point;
349 char **extension_points;
352 path = g_build_filename (dirname, name, NULL);
353 module = g_io_module_new (path);
355 extension_points = g_hash_table_lookup (cache, name);
356 if (extension_points != NULL &&
357 g_stat (path, &statbuf) == 0 &&
358 statbuf.st_ctime <= cache_mtime)
360 /* Lazy load/init the library when first required */
361 for (i = 0; extension_points[i] != NULL; i++)
364 g_io_extension_point_register (extension_points[i]);
365 extension_point->lazy_load_modules =
366 g_list_prepend (extension_point->lazy_load_modules,
372 /* Try to load and init types */
373 if (g_type_module_use (G_TYPE_MODULE (module)))
374 g_type_module_unuse (G_TYPE_MODULE (module)); /* Unload */
376 { /* Failure to load */
377 g_printerr ("Failed to load module: %s\n", path);
378 g_object_unref (module);
390 g_hash_table_destroy (cache);
397 * g_io_modules_load_all_in_directory:
398 * @dirname: pathname for a directory containing modules to load.
400 * Loads all the modules in the specified directory.
402 * If don't require all modules to be initialized (and thus registering
403 * all gtypes) then you can use g_io_modules_scan_all_in_directory()
404 * which allows delayed/lazy loading of modules.
406 * Returns: a list of #GIOModules loaded from the directory,
407 * All the modules are loaded into memory, if you want to
408 * unload them (enabling on-demand loading) you must call
409 * g_type_module_unuse() on all the modules. Free the list
410 * with g_list_free().
413 g_io_modules_load_all_in_directory (const char *dirname)
419 if (!g_module_supported ())
422 dir = g_dir_open (dirname, 0, NULL);
427 while ((name = g_dir_read_name (dir)))
429 if (is_valid_module_name (name))
434 path = g_build_filename (dirname, name, NULL);
435 module = g_io_module_new (path);
437 if (!g_type_module_use (G_TYPE_MODULE (module)))
439 g_printerr ("Failed to load module: %s\n", path);
440 g_object_unref (module);
447 modules = g_list_prepend (modules, module);
456 G_LOCK_DEFINE_STATIC (registered_extensions);
457 G_LOCK_DEFINE_STATIC (loaded_dirs);
459 extern GType _g_fen_directory_monitor_get_type (void);
460 extern GType _g_fen_file_monitor_get_type (void);
461 extern GType _g_inotify_directory_monitor_get_type (void);
462 extern GType _g_inotify_file_monitor_get_type (void);
463 extern GType _g_unix_volume_monitor_get_type (void);
464 extern GType _g_local_vfs_get_type (void);
466 extern GType _g_win32_volume_monitor_get_type (void);
467 extern GType g_win32_directory_monitor_get_type (void);
468 extern GType _g_winhttp_vfs_get_type (void);
470 #ifdef G_PLATFORM_WIN32
474 static HMODULE gio_dll = NULL;
479 DllMain (HINSTANCE hinstDLL,
483 if (fdwReason == DLL_PROCESS_ATTACH)
491 #undef GIO_MODULE_DIR
493 /* GIO_MODULE_DIR is used only in code called just once,
494 * so no problem leaking this
496 #define GIO_MODULE_DIR \
497 g_build_filename (g_win32_get_package_installation_directory_of_module (gio_dll), \
504 _g_io_modules_ensure_extension_points_registered (void)
506 static gboolean registered_extensions = FALSE;
507 GIOExtensionPoint *ep;
509 G_LOCK (registered_extensions);
511 if (!registered_extensions)
513 registered_extensions = TRUE;
516 ep = g_io_extension_point_register (G_DESKTOP_APP_INFO_LOOKUP_EXTENSION_POINT_NAME);
517 g_io_extension_point_set_required_type (ep, G_TYPE_DESKTOP_APP_INFO_LOOKUP);
520 ep = g_io_extension_point_register (G_LOCAL_DIRECTORY_MONITOR_EXTENSION_POINT_NAME);
521 g_io_extension_point_set_required_type (ep, G_TYPE_LOCAL_DIRECTORY_MONITOR);
523 ep = g_io_extension_point_register (G_LOCAL_FILE_MONITOR_EXTENSION_POINT_NAME);
524 g_io_extension_point_set_required_type (ep, G_TYPE_LOCAL_FILE_MONITOR);
526 ep = g_io_extension_point_register (G_VOLUME_MONITOR_EXTENSION_POINT_NAME);
527 g_io_extension_point_set_required_type (ep, G_TYPE_VOLUME_MONITOR);
529 ep = g_io_extension_point_register (G_NATIVE_VOLUME_MONITOR_EXTENSION_POINT_NAME);
530 g_io_extension_point_set_required_type (ep, G_TYPE_NATIVE_VOLUME_MONITOR);
532 ep = g_io_extension_point_register (G_VFS_EXTENSION_POINT_NAME);
533 g_io_extension_point_set_required_type (ep, G_TYPE_VFS);
535 ep = g_io_extension_point_register ("gsettings-backend");
536 g_io_extension_point_set_required_type (ep, G_TYPE_OBJECT);
539 G_UNLOCK (registered_extensions);
543 _g_io_modules_ensure_loaded (void)
545 static gboolean loaded_dirs = FALSE;
546 const char *module_path;
548 _g_io_modules_ensure_extension_points_registered ();
550 G_LOCK (loaded_dirs);
556 g_io_modules_scan_all_in_directory (GIO_MODULE_DIR);
558 module_path = g_getenv ("GIO_EXTRA_MODULES");
565 paths = g_strsplit (module_path, ":", 0);
567 for (i = 0; paths[i] != NULL; i++)
568 g_io_modules_scan_all_in_directory (paths[i]);
573 /* Initialize types from built-in "modules" */
574 g_memory_settings_backend_get_type ();
575 #if defined(HAVE_SYS_INOTIFY_H) || defined(HAVE_LINUX_INOTIFY_H)
576 _g_inotify_directory_monitor_get_type ();
577 _g_inotify_file_monitor_get_type ();
579 #if defined(HAVE_FEN)
580 _g_fen_directory_monitor_get_type ();
581 _g_fen_file_monitor_get_type ();
584 _g_win32_volume_monitor_get_type ();
585 g_win32_directory_monitor_get_type ();
588 _g_unix_volume_monitor_get_type ();
591 _g_winhttp_vfs_get_type ();
593 _g_local_vfs_get_type ();
596 G_UNLOCK (loaded_dirs);
600 g_io_extension_point_free (GIOExtensionPoint *ep)
607 * g_io_extension_point_register:
608 * @name: The name of the extension point
610 * Registers an extension point.
612 * Returns: the new #GIOExtensionPoint. This object is owned by GIO
613 * and should not be freed
616 g_io_extension_point_register (const char *name)
618 GIOExtensionPoint *ep;
620 G_LOCK (extension_points);
621 if (extension_points == NULL)
622 extension_points = g_hash_table_new_full (g_str_hash,
625 (GDestroyNotify)g_io_extension_point_free);
627 ep = g_hash_table_lookup (extension_points, name);
630 G_UNLOCK (extension_points);
634 ep = g_new0 (GIOExtensionPoint, 1);
635 ep->name = g_strdup (name);
637 g_hash_table_insert (extension_points, ep->name, ep);
639 G_UNLOCK (extension_points);
645 * g_io_extension_point_lookup:
646 * @name: the name of the extension point
648 * Looks up an existing extension point.
650 * Returns: the #GIOExtensionPoint, or %NULL if there is no
651 * registered extension point with the given name
654 g_io_extension_point_lookup (const char *name)
656 GIOExtensionPoint *ep;
658 G_LOCK (extension_points);
660 if (extension_points != NULL)
661 ep = g_hash_table_lookup (extension_points, name);
663 G_UNLOCK (extension_points);
670 * g_io_extension_point_set_required_type:
671 * @extension_point: a #GIOExtensionPoint
672 * @type: the #GType to require
674 * Sets the required type for @extension_point to @type.
675 * All implementations must henceforth have this type.
678 g_io_extension_point_set_required_type (GIOExtensionPoint *extension_point,
681 extension_point->required_type = type;
685 * g_io_extension_point_get_required_type:
686 * @extension_point: a #GIOExtensionPoint
688 * Gets the required type for @extension_point.
690 * Returns: the #GType that all implementations must have,
691 * or #G_TYPE_INVALID if the extension point has no required type
694 g_io_extension_point_get_required_type (GIOExtensionPoint *extension_point)
696 return extension_point->required_type;
700 lazy_load_modules (GIOExtensionPoint *extension_point)
705 for (l = extension_point->lazy_load_modules; l != NULL; l = l->next)
709 if (!module->initialized)
711 if (g_type_module_use (G_TYPE_MODULE (module)))
712 g_type_module_unuse (G_TYPE_MODULE (module)); /* Unload */
714 g_printerr ("Failed to load module: %s\n",
721 * g_io_extension_point_get_extensions:
722 * @extension_point: a #GIOExtensionPoint
724 * Gets a list of all extensions that implement this extension point.
725 * The list is sorted by priority, beginning with the highest priority.
727 * Returns: a #GList of #GIOExtension<!-- -->s. The list is owned by
728 * GIO and should not be modified
731 g_io_extension_point_get_extensions (GIOExtensionPoint *extension_point)
733 lazy_load_modules (extension_point);
734 return extension_point->extensions;
738 * g_io_extension_point_get_extension_by_name:
739 * @extension_point: a #GIOExtensionPoint
740 * @name: the name of the extension to get
742 * Finds a #GIOExtension for an extension point by name.
744 * Returns: the #GIOExtension for @extension_point that has the
745 * given name, or %NULL if there is no extension with that name
748 g_io_extension_point_get_extension_by_name (GIOExtensionPoint *extension_point,
753 lazy_load_modules (extension_point);
754 for (l = extension_point->extensions; l != NULL; l = l->next)
756 GIOExtension *e = l->data;
758 if (e->name != NULL &&
759 strcmp (e->name, name) == 0)
767 extension_prio_compare (gconstpointer a,
770 const GIOExtension *extension_a = a, *extension_b = b;
772 return extension_b->priority - extension_a->priority;
776 * g_io_extension_point_implement:
777 * @extension_point_name: the name of the extension point
778 * @type: the #GType to register as extension
779 * @extension_name: the name for the extension
780 * @priority: the priority for the extension
782 * Registers @type as extension for the extension point with name
783 * @extension_point_name.
785 * If @type has already been registered as an extension for this
786 * extension point, the existing #GIOExtension object is returned.
788 * Returns: a #GIOExtension object for #GType
791 g_io_extension_point_implement (const char *extension_point_name,
793 const char *extension_name,
796 GIOExtensionPoint *extension_point;
797 GIOExtension *extension;
800 g_return_val_if_fail (extension_point_name != NULL, NULL);
802 extension_point = g_io_extension_point_lookup (extension_point_name);
803 if (extension_point == NULL)
805 g_warning ("Tried to implement non-registered extension point %s", extension_point_name);
809 if (extension_point->required_type != 0 &&
810 !g_type_is_a (type, extension_point->required_type))
812 g_warning ("Tried to register an extension of the type %s to extension point %s. "
813 "Expected type is %s.",
815 extension_point_name,
816 g_type_name (extension_point->required_type));
820 /* It's safe to register the same type multiple times */
821 for (l = extension_point->extensions; l != NULL; l = l->next)
824 if (extension->type == type)
828 extension = g_slice_new0 (GIOExtension);
829 extension->type = type;
830 extension->name = g_strdup (extension_name);
831 extension->priority = priority;
833 extension_point->extensions = g_list_insert_sorted (extension_point->extensions,
834 extension, extension_prio_compare);
840 * g_io_extension_ref_class:
841 * @extension: a #GIOExtension
843 * Gets a reference to the class for the type that is
844 * associated with @extension.
846 * Returns: the #GTypeClass for the type of @extension
849 g_io_extension_ref_class (GIOExtension *extension)
851 return g_type_class_ref (extension->type);
855 * g_io_extension_get_type:
856 * @extension: a #GIOExtension
858 * Gets the type associated with @extension.
860 * Returns: the type of @extension
863 g_io_extension_get_type (GIOExtension *extension)
865 return extension->type;
869 * g_io_extension_get_name:
870 * @extension: a #GIOExtension
872 * Gets the name under which @extension was registered.
874 * Note that the same type may be registered as extension
875 * for multiple extension points, under different names.
877 * Returns: the name of @extension.
880 g_io_extension_get_name (GIOExtension *extension)
882 return extension->name;
886 * g_io_extension_get_priority:
887 * @extension: a #GIOExtension
889 * Gets the priority with which @extension was registered.
891 * Returns: the priority of @extension
894 g_io_extension_get_priority (GIOExtension *extension)
896 return extension->priority;