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 "glocalfilemonitor.h"
30 #include "glocaldirectorymonitor.h"
31 #include "gnativevolumemonitor.h"
34 #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
95 GTypeModule parent_instance;
99 gboolean initialized; /* The module was loaded at least once */
101 void (* load) (GIOModule *module);
102 void (* unload) (GIOModule *module);
105 struct _GIOModuleClass
107 GTypeModuleClass parent_class;
111 static void g_io_module_finalize (GObject *object);
112 static gboolean g_io_module_load_module (GTypeModule *gmodule);
113 static void g_io_module_unload_module (GTypeModule *gmodule);
115 struct _GIOExtension {
121 struct _GIOExtensionPoint {
125 GList *lazy_load_modules;
128 static GHashTable *extension_points = NULL;
129 G_LOCK_DEFINE_STATIC(extension_points);
131 G_DEFINE_TYPE (GIOModule, g_io_module, G_TYPE_TYPE_MODULE);
134 g_io_module_class_init (GIOModuleClass *class)
136 GObjectClass *object_class = G_OBJECT_CLASS (class);
137 GTypeModuleClass *type_module_class = G_TYPE_MODULE_CLASS (class);
139 object_class->finalize = g_io_module_finalize;
141 type_module_class->load = g_io_module_load_module;
142 type_module_class->unload = g_io_module_unload_module;
146 g_io_module_init (GIOModule *module)
151 g_io_module_finalize (GObject *object)
153 GIOModule *module = G_IO_MODULE (object);
155 g_free (module->filename);
157 G_OBJECT_CLASS (g_io_module_parent_class)->finalize (object);
161 g_io_module_load_module (GTypeModule *gmodule)
163 GIOModule *module = G_IO_MODULE (gmodule);
165 if (!module->filename)
167 g_warning ("GIOModule path not set");
171 module->library = g_module_open (module->filename, G_MODULE_BIND_LAZY | G_MODULE_BIND_LOCAL);
173 if (!module->library)
175 g_printerr ("%s\n", g_module_error ());
179 /* Make sure that the loaded library contains the required methods */
180 if (! g_module_symbol (module->library,
182 (gpointer) &module->load) ||
183 ! g_module_symbol (module->library,
184 "g_io_module_unload",
185 (gpointer) &module->unload))
187 g_printerr ("%s\n", g_module_error ());
188 g_module_close (module->library);
193 /* Initialize the loaded module */
194 module->load (module);
195 module->initialized = TRUE;
201 g_io_module_unload_module (GTypeModule *gmodule)
203 GIOModule *module = G_IO_MODULE (gmodule);
205 module->unload (module);
207 g_module_close (module->library);
208 module->library = NULL;
211 module->unload = NULL;
216 * @filename: filename of the shared library module.
218 * Creates a new GIOModule that will load the specific
219 * shared library when in use.
221 * Returns: a #GIOModule from given @filename,
225 g_io_module_new (const gchar *filename)
229 g_return_val_if_fail (filename != NULL, NULL);
231 module = g_object_new (G_IO_TYPE_MODULE, NULL);
232 module->filename = g_strdup (filename);
238 is_valid_module_name (const gchar *basename)
240 #if !defined(G_OS_WIN32) && !defined(G_WITH_CYGWIN)
242 g_str_has_prefix (basename, "lib") &&
243 g_str_has_suffix (basename, ".so");
245 return g_str_has_suffix (basename, ".dll");
250 * g_io_modules_scan_all_in_directory:
251 * @dirname: pathname for a directory containing modules to scan.
253 * Scans all the modules in the specified directory, ensuring that
254 * any extension point implemented by a module is registered.
256 * This may not actually load and initialize all the types in each
257 * module, some modules may be lazily loaded and initialized when
258 * an extension point it implementes is used with e.g.
259 * g_io_extension_point_get_extensions() or
260 * g_io_extension_point_get_extension_by_name().
262 * If you need to guarantee that all types are loaded in all the modules,
263 * use g_io_modules_scan_all_in_directory().
268 g_io_modules_scan_all_in_directory (const char *dirname)
274 struct _g_stat_struct statbuf;
282 if (!g_module_supported ())
285 dir = g_dir_open (dirname, 0, NULL);
289 filename = g_build_filename (dirname, "giomodule.cache", NULL);
291 cache = g_hash_table_new_full (g_str_hash, g_str_equal,
292 g_free, (GDestroyNotify)g_strfreev);
295 if (g_stat (filename, &statbuf) == 0 &&
296 g_file_get_contents (filename, &data, NULL, NULL))
301 /* Cache mtime is the time the cache file was created, any file
302 * that has a ctime before this was created then and not modified
303 * since then (userspace can't change ctime). Its possible to change
304 * the ctime forward without changing the file content, by e.g.
305 * chmoding the file, but this is uncommon and will only cause us
306 * to not use the cache so will not cause bugs.
308 cache_mtime = statbuf.st_mtime;
310 lines = g_strsplit (data, "\n", -1);
313 for (i = 0; lines[i] != NULL; i++)
315 char *line = lines[i];
318 char **extension_points;
323 colon = strchr (line, ':');
324 if (colon == NULL || line == colon)
325 continue; /* Invalid line, ignore */
327 *colon = 0; /* terminate filename */
328 file = g_strdup (line);
329 colon++; /* after colon */
331 while (g_ascii_isspace (*colon))
334 extension_points = g_strsplit (colon, ",", -1);
335 g_hash_table_insert (cache, file, extension_points);
340 while ((name = g_dir_read_name (dir)))
342 if (is_valid_module_name (name))
344 GIOExtensionPoint *extension_point;
347 char **extension_points;
350 path = g_build_filename (dirname, name, NULL);
351 module = g_io_module_new (path);
353 extension_points = g_hash_table_lookup (cache, name);
354 if (extension_points != NULL &&
355 g_stat (path, &statbuf) == 0 &&
356 statbuf.st_ctime <= cache_mtime)
358 /* Lazy load/init the library when first required */
359 for (i = 0; extension_points[i] != NULL; i++)
362 g_io_extension_point_register (extension_points[i]);
363 extension_point->lazy_load_modules =
364 g_list_prepend (extension_point->lazy_load_modules,
370 /* Try to load and init types */
371 if (g_type_module_use (G_TYPE_MODULE (module)))
372 g_type_module_unuse (G_TYPE_MODULE (module)); /* Unload */
374 { /* Failure to load */
375 g_printerr ("Failed to load module: %s\n", path);
376 g_object_unref (module);
388 g_hash_table_destroy (cache);
395 * g_io_modules_load_all_in_directory:
396 * @dirname: pathname for a directory containing modules to load.
398 * Loads all the modules in the specified directory.
400 * If don't require all modules to be initialized (and thus registering
401 * all gtypes) then you can use g_io_modules_scan_all_in_directory()
402 * which allows delayed/lazy loading of modules.
404 * Returns: a list of #GIOModules loaded from the directory,
405 * All the modules are loaded into memory, if you want to
406 * unload them (enabling on-demand loading) you must call
407 * g_type_module_unuse() on all the modules. Free the list
408 * with g_list_free().
411 g_io_modules_load_all_in_directory (const char *dirname)
417 if (!g_module_supported ())
420 dir = g_dir_open (dirname, 0, NULL);
425 while ((name = g_dir_read_name (dir)))
427 if (is_valid_module_name (name))
432 path = g_build_filename (dirname, name, NULL);
433 module = g_io_module_new (path);
435 if (!g_type_module_use (G_TYPE_MODULE (module)))
437 g_printerr ("Failed to load module: %s\n", path);
438 g_object_unref (module);
445 modules = g_list_prepend (modules, module);
454 G_LOCK_DEFINE_STATIC (registered_extensions);
455 G_LOCK_DEFINE_STATIC (loaded_dirs);
457 extern GType _g_fen_directory_monitor_get_type (void);
458 extern GType _g_fen_file_monitor_get_type (void);
459 extern GType _g_inotify_directory_monitor_get_type (void);
460 extern GType _g_inotify_file_monitor_get_type (void);
461 extern GType _g_unix_volume_monitor_get_type (void);
462 extern GType _g_local_vfs_get_type (void);
464 extern GType _g_win32_volume_monitor_get_type (void);
465 extern GType g_win32_directory_monitor_get_type (void);
466 extern GType _g_winhttp_vfs_get_type (void);
468 #ifdef G_PLATFORM_WIN32
472 static HMODULE gio_dll = NULL;
477 DllMain (HINSTANCE hinstDLL,
481 if (fdwReason == DLL_PROCESS_ATTACH)
489 #undef GIO_MODULE_DIR
491 /* GIO_MODULE_DIR is used only in code called just once,
492 * so no problem leaking this
494 #define GIO_MODULE_DIR \
495 g_build_filename (g_win32_get_package_installation_directory_of_module (gio_dll), \
502 _g_io_modules_ensure_extension_points_registered (void)
504 static gboolean registered_extensions = FALSE;
505 GIOExtensionPoint *ep;
507 G_LOCK (registered_extensions);
509 if (!registered_extensions)
511 registered_extensions = TRUE;
514 ep = g_io_extension_point_register (G_DESKTOP_APP_INFO_LOOKUP_EXTENSION_POINT_NAME);
515 g_io_extension_point_set_required_type (ep, G_TYPE_DESKTOP_APP_INFO_LOOKUP);
518 ep = g_io_extension_point_register (G_LOCAL_DIRECTORY_MONITOR_EXTENSION_POINT_NAME);
519 g_io_extension_point_set_required_type (ep, G_TYPE_LOCAL_DIRECTORY_MONITOR);
521 ep = g_io_extension_point_register (G_LOCAL_FILE_MONITOR_EXTENSION_POINT_NAME);
522 g_io_extension_point_set_required_type (ep, G_TYPE_LOCAL_FILE_MONITOR);
524 ep = g_io_extension_point_register (G_VOLUME_MONITOR_EXTENSION_POINT_NAME);
525 g_io_extension_point_set_required_type (ep, G_TYPE_VOLUME_MONITOR);
527 ep = g_io_extension_point_register (G_NATIVE_VOLUME_MONITOR_EXTENSION_POINT_NAME);
528 g_io_extension_point_set_required_type (ep, G_TYPE_NATIVE_VOLUME_MONITOR);
530 ep = g_io_extension_point_register (G_VFS_EXTENSION_POINT_NAME);
531 g_io_extension_point_set_required_type (ep, G_TYPE_VFS);
533 ep = g_io_extension_point_register ("gsettings-backend");
534 g_io_extension_point_set_required_type (ep, G_TYPE_OBJECT);
537 G_UNLOCK (registered_extensions);
541 _g_io_modules_ensure_loaded (void)
543 static gboolean loaded_dirs = FALSE;
544 const char *module_path;
546 _g_io_modules_ensure_extension_points_registered ();
548 G_LOCK (loaded_dirs);
554 g_io_modules_scan_all_in_directory (GIO_MODULE_DIR);
556 module_path = g_getenv ("GIO_EXTRA_MODULES");
563 paths = g_strsplit (module_path, ":", 0);
565 for (i = 0; paths[i] != NULL; i++)
566 g_io_modules_scan_all_in_directory (paths[i]);
571 /* Initialize types from built-in "modules" */
572 #if defined(HAVE_SYS_INOTIFY_H) || defined(HAVE_LINUX_INOTIFY_H)
573 _g_inotify_directory_monitor_get_type ();
574 _g_inotify_file_monitor_get_type ();
576 #if defined(HAVE_FEN)
577 _g_fen_directory_monitor_get_type ();
578 _g_fen_file_monitor_get_type ();
581 _g_win32_volume_monitor_get_type ();
582 g_win32_directory_monitor_get_type ();
585 _g_unix_volume_monitor_get_type ();
588 _g_winhttp_vfs_get_type ();
590 _g_local_vfs_get_type ();
593 G_UNLOCK (loaded_dirs);
597 g_io_extension_point_free (GIOExtensionPoint *ep)
604 * g_io_extension_point_register:
605 * @name: The name of the extension point
607 * Registers an extension point.
609 * Returns: the new #GIOExtensionPoint. This object is owned by GIO
610 * and should not be freed
613 g_io_extension_point_register (const char *name)
615 GIOExtensionPoint *ep;
617 G_LOCK (extension_points);
618 if (extension_points == NULL)
619 extension_points = g_hash_table_new_full (g_str_hash,
622 (GDestroyNotify)g_io_extension_point_free);
624 ep = g_hash_table_lookup (extension_points, name);
627 G_UNLOCK (extension_points);
631 ep = g_new0 (GIOExtensionPoint, 1);
632 ep->name = g_strdup (name);
634 g_hash_table_insert (extension_points, ep->name, ep);
636 G_UNLOCK (extension_points);
642 * g_io_extension_point_lookup:
643 * @name: the name of the extension point
645 * Looks up an existing extension point.
647 * Returns: the #GIOExtensionPoint, or %NULL if there is no
648 * registered extension point with the given name
651 g_io_extension_point_lookup (const char *name)
653 GIOExtensionPoint *ep;
655 G_LOCK (extension_points);
657 if (extension_points != NULL)
658 ep = g_hash_table_lookup (extension_points, name);
660 G_UNLOCK (extension_points);
667 * g_io_extension_point_set_required_type:
668 * @extension_point: a #GIOExtensionPoint
669 * @type: the #GType to require
671 * Sets the required type for @extension_point to @type.
672 * All implementations must henceforth have this type.
675 g_io_extension_point_set_required_type (GIOExtensionPoint *extension_point,
678 extension_point->required_type = type;
682 * g_io_extension_point_get_required_type:
683 * @extension_point: a #GIOExtensionPoint
685 * Gets the required type for @extension_point.
687 * Returns: the #GType that all implementations must have,
688 * or #G_TYPE_INVALID if the extension point has no required type
691 g_io_extension_point_get_required_type (GIOExtensionPoint *extension_point)
693 return extension_point->required_type;
697 lazy_load_modules (GIOExtensionPoint *extension_point)
702 for (l = extension_point->lazy_load_modules; l != NULL; l = l->next)
706 if (!module->initialized)
708 if (g_type_module_use (G_TYPE_MODULE (module)))
709 g_type_module_unuse (G_TYPE_MODULE (module)); /* Unload */
711 g_printerr ("Failed to load module: %s\n",
718 * g_io_extension_point_get_extensions:
719 * @extension_point: a #GIOExtensionPoint
721 * Gets a list of all extensions that implement this extension point.
722 * The list is sorted by priority, beginning with the highest priority.
724 * Returns: a #GList of #GIOExtension<!-- -->s. The list is owned by
725 * GIO and should not be modified
728 g_io_extension_point_get_extensions (GIOExtensionPoint *extension_point)
730 lazy_load_modules (extension_point);
731 return extension_point->extensions;
735 * g_io_extension_point_get_extension_by_name:
736 * @extension_point: a #GIOExtensionPoint
737 * @name: the name of the extension to get
739 * Finds a #GIOExtension for an extension point by name.
741 * Returns: the #GIOExtension for @extension_point that has the
742 * given name, or %NULL if there is no extension with that name
745 g_io_extension_point_get_extension_by_name (GIOExtensionPoint *extension_point,
750 lazy_load_modules (extension_point);
751 for (l = extension_point->extensions; l != NULL; l = l->next)
753 GIOExtension *e = l->data;
755 if (e->name != NULL &&
756 strcmp (e->name, name) == 0)
764 extension_prio_compare (gconstpointer a,
767 const GIOExtension *extension_a = a, *extension_b = b;
769 return extension_b->priority - extension_a->priority;
773 * g_io_extension_point_implement:
774 * @extension_point_name: the name of the extension point
775 * @type: the #GType to register as extension
776 * @extension_name: the name for the extension
777 * @priority: the priority for the extension
779 * Registers @type as extension for the extension point with name
780 * @extension_point_name.
782 * If @type has already been registered as an extension for this
783 * extension point, the existing #GIOExtension object is returned.
785 * Returns: a #GIOExtension object for #GType
788 g_io_extension_point_implement (const char *extension_point_name,
790 const char *extension_name,
793 GIOExtensionPoint *extension_point;
794 GIOExtension *extension;
797 g_return_val_if_fail (extension_point_name != NULL, NULL);
799 extension_point = g_io_extension_point_lookup (extension_point_name);
800 if (extension_point == NULL)
802 g_warning ("Tried to implement non-registered extension point %s", extension_point_name);
806 if (extension_point->required_type != 0 &&
807 !g_type_is_a (type, extension_point->required_type))
809 g_warning ("Tried to register an extension of the type %s to extension point %s. "
810 "Expected type is %s.",
812 extension_point_name,
813 g_type_name (extension_point->required_type));
817 /* It's safe to register the same type multiple times */
818 for (l = extension_point->extensions; l != NULL; l = l->next)
821 if (extension->type == type)
825 extension = g_slice_new0 (GIOExtension);
826 extension->type = type;
827 extension->name = g_strdup (extension_name);
828 extension->priority = priority;
830 extension_point->extensions = g_list_insert_sorted (extension_point->extensions,
831 extension, extension_prio_compare);
837 * g_io_extension_ref_class:
838 * @extension: a #GIOExtension
840 * Gets a reference to the class for the type that is
841 * associated with @extension.
843 * Returns: the #GTypeClass for the type of @extension
846 g_io_extension_ref_class (GIOExtension *extension)
848 return g_type_class_ref (extension->type);
852 * g_io_extension_get_type:
853 * @extension: a #GIOExtension
855 * Gets the type associated with @extension.
857 * Returns: the type of @extension
860 g_io_extension_get_type (GIOExtension *extension)
862 return extension->type;
866 * g_io_extension_get_name:
867 * @extension: a #GIOExtension
869 * Gets the name under which @extension was registered.
871 * Note that the same type may be registered as extension
872 * for multiple extension points, under different names.
874 * Returns: the name of @extension.
877 g_io_extension_get_name (GIOExtension *extension)
879 return extension->name;
883 * g_io_extension_get_priority:
884 * @extension: a #GIOExtension
886 * Gets the priority with which @extension was registered.
888 * Returns: the priority of @extension
891 g_io_extension_get_priority (GIOExtension *extension)
893 return extension->priority;
896 #define __G_IO_MODULE_C__
897 #include "gioaliasdef.c"