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)
278 if (!g_module_supported ())
281 dir = g_dir_open (dirname, 0, NULL);
285 filename = g_build_filename (dirname, "giomodule.cache", NULL);
287 cache = g_hash_table_new_full (g_str_hash, g_str_equal,
288 g_free, (GDestroyNotify)g_strfreev);
291 if (g_stat (filename, &statbuf) == 0 &&
292 g_file_get_contents (filename, &data, NULL, NULL))
297 /* Cache mtime is the time the cache file was created, any file
298 * that has a ctime before this was created then and not modified
299 * since then (userspace can't change ctime). Its possible to change
300 * the ctime forward without changing the file content, by e.g.
301 * chmoding the file, but this is uncommon and will only cause us
302 * to not use the cache so will not cause bugs.
304 cache_mtime = statbuf.st_mtime;
306 lines = g_strsplit (data, "\n", -1);
309 for (i = 0; lines[i] != NULL; i++)
311 char *line = lines[i];
314 char **extension_points;
319 colon = strchr (line, ':');
320 if (colon == NULL || line == colon)
321 continue; /* Invalid line, ignore */
323 *colon = 0; /* terminate filename */
324 file = strdup (line);
325 colon++; /* after colon */
327 while (g_ascii_isspace (*colon))
330 extension_points = g_strsplit (colon, ",", -1);
331 g_hash_table_insert (cache, g_strdup (file), extension_points);
336 while ((name = g_dir_read_name (dir)))
338 if (is_valid_module_name (name))
340 GIOExtensionPoint *extension_point;
343 char **extension_points;
346 path = g_build_filename (dirname, name, NULL);
347 module = g_io_module_new (path);
349 extension_points = g_hash_table_lookup (cache, name);
350 if (extension_points != NULL &&
351 g_stat (path, &statbuf) == 0 &&
352 statbuf.st_ctime <= cache_mtime)
354 /* Lazy load/init the library when first required */
355 for (i = 0; extension_points[i] != NULL; i++)
358 g_io_extension_point_register (extension_points[i]);
359 extension_point->lazy_load_modules =
360 g_list_prepend (extension_point->lazy_load_modules,
366 /* Try to load and init types */
367 if (g_type_module_use (G_TYPE_MODULE (module)))
368 g_type_module_unuse (G_TYPE_MODULE (module)); /* Unload */
370 { /* Failure to load */
371 g_printerr ("Failed to load module: %s\n", path);
372 g_object_unref (module);
384 g_hash_table_destroy (cache);
389 * g_io_modules_load_all_in_directory:
390 * @dirname: pathname for a directory containing modules to load.
392 * Loads all the modules in the specified directory.
394 * If don't require all modules to be initialized (and thus registering
395 * all gtypes) then you can use g_io_modules_scan_all_in_directory()
396 * which allows delayed/lazy loading of modules.
398 * Returns: a list of #GIOModules loaded from the directory,
399 * All the modules are loaded into memory, if you want to
400 * unload them (enabling on-demand loading) you must call
401 * g_type_module_unuse() on all the modules. Free the list
402 * with g_list_free().
405 g_io_modules_load_all_in_directory (const char *dirname)
411 if (!g_module_supported ())
414 dir = g_dir_open (dirname, 0, NULL);
419 while ((name = g_dir_read_name (dir)))
421 if (is_valid_module_name (name))
426 path = g_build_filename (dirname, name, NULL);
427 module = g_io_module_new (path);
429 if (!g_type_module_use (G_TYPE_MODULE (module)))
431 g_printerr ("Failed to load module: %s\n", path);
432 g_object_unref (module);
439 modules = g_list_prepend (modules, module);
448 G_LOCK_DEFINE_STATIC (registered_extensions);
449 G_LOCK_DEFINE_STATIC (loaded_dirs);
451 extern GType _g_fen_directory_monitor_get_type (void);
452 extern GType _g_fen_file_monitor_get_type (void);
453 extern GType _g_inotify_directory_monitor_get_type (void);
454 extern GType _g_inotify_file_monitor_get_type (void);
455 extern GType _g_unix_volume_monitor_get_type (void);
456 extern GType _g_local_vfs_get_type (void);
458 extern GType _g_win32_volume_monitor_get_type (void);
459 extern GType g_win32_directory_monitor_get_type (void);
460 extern GType _g_winhttp_vfs_get_type (void);
462 #ifdef G_PLATFORM_WIN32
466 static HMODULE gio_dll = NULL;
471 DllMain (HINSTANCE hinstDLL,
475 if (fdwReason == DLL_PROCESS_ATTACH)
483 #undef GIO_MODULE_DIR
485 /* GIO_MODULE_DIR is used only in code called just once,
486 * so no problem leaking this
488 #define GIO_MODULE_DIR \
489 g_build_filename (g_win32_get_package_installation_directory_of_module (gio_dll), \
496 _g_io_modules_ensure_extension_points_registered (void)
498 static gboolean registered_extensions = FALSE;
499 GIOExtensionPoint *ep;
501 G_LOCK (registered_extensions);
503 if (!registered_extensions)
505 registered_extensions = TRUE;
508 ep = g_io_extension_point_register (G_DESKTOP_APP_INFO_LOOKUP_EXTENSION_POINT_NAME);
509 g_io_extension_point_set_required_type (ep, G_TYPE_DESKTOP_APP_INFO_LOOKUP);
512 ep = g_io_extension_point_register (G_LOCAL_DIRECTORY_MONITOR_EXTENSION_POINT_NAME);
513 g_io_extension_point_set_required_type (ep, G_TYPE_LOCAL_DIRECTORY_MONITOR);
515 ep = g_io_extension_point_register (G_LOCAL_FILE_MONITOR_EXTENSION_POINT_NAME);
516 g_io_extension_point_set_required_type (ep, G_TYPE_LOCAL_FILE_MONITOR);
518 ep = g_io_extension_point_register (G_VOLUME_MONITOR_EXTENSION_POINT_NAME);
519 g_io_extension_point_set_required_type (ep, G_TYPE_VOLUME_MONITOR);
521 ep = g_io_extension_point_register (G_NATIVE_VOLUME_MONITOR_EXTENSION_POINT_NAME);
522 g_io_extension_point_set_required_type (ep, G_TYPE_NATIVE_VOLUME_MONITOR);
524 ep = g_io_extension_point_register (G_VFS_EXTENSION_POINT_NAME);
525 g_io_extension_point_set_required_type (ep, G_TYPE_VFS);
527 ep = g_io_extension_point_register ("gsettings-backend");
528 g_io_extension_point_set_required_type (ep, G_TYPE_OBJECT);
531 G_UNLOCK (registered_extensions);
535 _g_io_modules_ensure_loaded (void)
537 static gboolean loaded_dirs = FALSE;
538 const char *module_path;
540 _g_io_modules_ensure_extension_points_registered ();
542 G_LOCK (loaded_dirs);
548 g_io_modules_scan_all_in_directory (GIO_MODULE_DIR);
550 module_path = g_getenv ("GIO_EXTRA_MODULES");
557 paths = g_strsplit (module_path, ":", 0);
559 for (i = 0; paths[i] != NULL; i++)
560 g_io_modules_scan_all_in_directory (paths[i]);
565 /* Initialize types from built-in "modules" */
566 #if defined(HAVE_SYS_INOTIFY_H) || defined(HAVE_LINUX_INOTIFY_H)
567 _g_inotify_directory_monitor_get_type ();
568 _g_inotify_file_monitor_get_type ();
570 #if defined(HAVE_FEN)
571 _g_fen_directory_monitor_get_type ();
572 _g_fen_file_monitor_get_type ();
575 _g_win32_volume_monitor_get_type ();
576 g_win32_directory_monitor_get_type ();
579 _g_unix_volume_monitor_get_type ();
582 _g_winhttp_vfs_get_type ();
584 _g_local_vfs_get_type ();
587 G_UNLOCK (loaded_dirs);
591 g_io_extension_point_free (GIOExtensionPoint *ep)
598 * g_io_extension_point_register:
599 * @name: The name of the extension point
601 * Registers an extension point.
603 * Returns: the new #GIOExtensionPoint. This object is owned by GIO
604 * and should not be freed
607 g_io_extension_point_register (const char *name)
609 GIOExtensionPoint *ep;
611 G_LOCK (extension_points);
612 if (extension_points == NULL)
613 extension_points = g_hash_table_new_full (g_str_hash,
616 (GDestroyNotify)g_io_extension_point_free);
618 ep = g_hash_table_lookup (extension_points, name);
621 G_UNLOCK (extension_points);
625 ep = g_new0 (GIOExtensionPoint, 1);
626 ep->name = g_strdup (name);
628 g_hash_table_insert (extension_points, ep->name, ep);
630 G_UNLOCK (extension_points);
636 * g_io_extension_point_lookup:
637 * @name: the name of the extension point
639 * Looks up an existing extension point.
641 * Returns: the #GIOExtensionPoint, or %NULL if there is no
642 * registered extension point with the given name
645 g_io_extension_point_lookup (const char *name)
647 GIOExtensionPoint *ep;
649 G_LOCK (extension_points);
651 if (extension_points != NULL)
652 ep = g_hash_table_lookup (extension_points, name);
654 G_UNLOCK (extension_points);
661 * g_io_extension_point_set_required_type:
662 * @extension_point: a #GIOExtensionPoint
663 * @type: the #GType to require
665 * Sets the required type for @extension_point to @type.
666 * All implementations must henceforth have this type.
669 g_io_extension_point_set_required_type (GIOExtensionPoint *extension_point,
672 extension_point->required_type = type;
676 * g_io_extension_point_get_required_type:
677 * @extension_point: a #GIOExtensionPoint
679 * Gets the required type for @extension_point.
681 * Returns: the #GType that all implementations must have,
682 * or #G_TYPE_INVALID if the extension point has no required type
685 g_io_extension_point_get_required_type (GIOExtensionPoint *extension_point)
687 return extension_point->required_type;
691 lazy_load_modules (GIOExtensionPoint *extension_point)
696 for (l = extension_point->lazy_load_modules; l != NULL; l = l->next)
700 if (!module->initialized)
702 if (g_type_module_use (G_TYPE_MODULE (module)))
703 g_type_module_unuse (G_TYPE_MODULE (module)); /* Unload */
705 g_printerr ("Failed to load module: %s\n",
712 * g_io_extension_point_get_extensions:
713 * @extension_point: a #GIOExtensionPoint
715 * Gets a list of all extensions that implement this extension point.
716 * The list is sorted by priority, beginning with the highest priority.
718 * Returns: a #GList of #GIOExtension<!-- -->s. The list is owned by
719 * GIO and should not be modified
722 g_io_extension_point_get_extensions (GIOExtensionPoint *extension_point)
724 lazy_load_modules (extension_point);
725 return extension_point->extensions;
729 * g_io_extension_point_get_extension_by_name:
730 * @extension_point: a #GIOExtensionPoint
731 * @name: the name of the extension to get
733 * Finds a #GIOExtension for an extension point by name.
735 * Returns: the #GIOExtension for @extension_point that has the
736 * given name, or %NULL if there is no extension with that name
739 g_io_extension_point_get_extension_by_name (GIOExtensionPoint *extension_point,
744 lazy_load_modules (extension_point);
745 for (l = extension_point->extensions; l != NULL; l = l->next)
747 GIOExtension *e = l->data;
749 if (e->name != NULL &&
750 strcmp (e->name, name) == 0)
758 extension_prio_compare (gconstpointer a,
761 const GIOExtension *extension_a = a, *extension_b = b;
763 return extension_b->priority - extension_a->priority;
767 * g_io_extension_point_implement:
768 * @extension_point_name: the name of the extension point
769 * @type: the #GType to register as extension
770 * @extension_name: the name for the extension
771 * @priority: the priority for the extension
773 * Registers @type as extension for the extension point with name
774 * @extension_point_name.
776 * If @type has already been registered as an extension for this
777 * extension point, the existing #GIOExtension object is returned.
779 * Returns: a #GIOExtension object for #GType
782 g_io_extension_point_implement (const char *extension_point_name,
784 const char *extension_name,
787 GIOExtensionPoint *extension_point;
788 GIOExtension *extension;
791 g_return_val_if_fail (extension_point_name != NULL, NULL);
793 extension_point = g_io_extension_point_lookup (extension_point_name);
794 if (extension_point == NULL)
796 g_warning ("Tried to implement non-registered extension point %s", extension_point_name);
800 if (extension_point->required_type != 0 &&
801 !g_type_is_a (type, extension_point->required_type))
803 g_warning ("Tried to register an extension of the type %s to extension point %s. "
804 "Expected type is %s.",
806 extension_point_name,
807 g_type_name (extension_point->required_type));
811 /* It's safe to register the same type multiple times */
812 for (l = extension_point->extensions; l != NULL; l = l->next)
815 if (extension->type == type)
819 extension = g_slice_new0 (GIOExtension);
820 extension->type = type;
821 extension->name = g_strdup (extension_name);
822 extension->priority = priority;
824 extension_point->extensions = g_list_insert_sorted (extension_point->extensions,
825 extension, extension_prio_compare);
831 * g_io_extension_ref_class:
832 * @extension: a #GIOExtension
834 * Gets a reference to the class for the type that is
835 * associated with @extension.
837 * Returns: the #GTypeClass for the type of @extension
840 g_io_extension_ref_class (GIOExtension *extension)
842 return g_type_class_ref (extension->type);
846 * g_io_extension_get_type:
847 * @extension: a #GIOExtension
849 * Gets the type associated with @extension.
851 * Returns: the type of @extension
854 g_io_extension_get_type (GIOExtension *extension)
856 return extension->type;
860 * g_io_extension_get_name:
861 * @extension: a #GIOExtension
863 * Gets the name under which @extension was registered.
865 * Note that the same type may be registered as extension
866 * for multiple extension points, under different names.
868 * Returns: the name of @extension.
871 g_io_extension_get_name (GIOExtension *extension)
873 return extension->name;
877 * g_io_extension_get_priority:
878 * @extension: a #GIOExtension
880 * Gets the priority with which @extension was registered.
882 * Returns: the priority of @extension
885 g_io_extension_get_priority (GIOExtension *extension)
887 return extension->priority;
890 #define __G_IO_MODULE_C__
891 #include "gioaliasdef.c"