/* GIO - GLib Input, Output and Streaming Library * * Copyright (C) 2006-2007 Red Hat, Inc. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General * Public License along with this library; if not, write to the * Free Software Foundation, Inc., 59 Temple Place, Suite 330, * Boston, MA 02111-1307, USA. * * Author: Alexander Larsson */ #include #include #include "giomodule.h" #include "giomodule-priv.h" #include "glocalfilemonitor.h" #include "glocaldirectorymonitor.h" #include "gnativevolumemonitor.h" #include "gvfs.h" #ifdef G_OS_UNIX #include "gdesktopappinfo.h" #endif #include "gioalias.h" /** * SECTION:giomodule * @short_description: Loadable GIO Modules * @include: gio/gio.h * * Provides an interface and default functions for loading and unloading * modules. This is used internally to make GIO extensible, but can also * be used by others to implement module loading. * **/ /** * SECTION:extensionpoints * @short_description: Extension Points * @include: gio.h * @see_also: Extending GIO * * #GIOExtensionPoint provides a mechanism for modules to extend the * functionality of the library or application that loaded it in an * organized fashion. * * An extension point is identified by a name, and it may optionally * require that any implementation must by of a certain type (or derived * thereof). Use g_io_extension_point_register() to register an * extension point, and g_io_extension_point_set_required_type() to * set a required type. * * A module can implement an extension point by specifying the #GType * that implements the functionality. Additionally, each implementation * of an extension point has a name, and a priority. Use * g_io_extension_point_implement() to implement an extension point. * * |[ * GIOExtensionPoint *ep; * * /* Register an extension point */ * ep = g_io_extension_point_register ("my-extension-point"); * g_io_extension_point_set_required_type (ep, MY_TYPE_EXAMPLE); * ]| * * |[ * /* Implement an extension point */ * G_DEFINE_TYPE (MyExampleImpl, my_example_impl, MY_TYPE_EXAMPLE); * g_io_extension_point_implement ("my-extension-point", * my_example_impl_get_type (), * "my-example", * 10); * ]| * * It is up to the code that registered the extension point how * it uses the implementations that have been associated with it. * Depending on the use case, it may use all implementations, or * only the one with the highest priority, or pick a specific * one by name. */ struct _GIOModule { GTypeModule parent_instance; gchar *filename; GModule *library; void (* load) (GIOModule *module); void (* unload) (GIOModule *module); }; struct _GIOModuleClass { GTypeModuleClass parent_class; }; static void g_io_module_finalize (GObject *object); static gboolean g_io_module_load_module (GTypeModule *gmodule); static void g_io_module_unload_module (GTypeModule *gmodule); G_DEFINE_TYPE (GIOModule, g_io_module, G_TYPE_TYPE_MODULE); static void g_io_module_class_init (GIOModuleClass *class) { GObjectClass *object_class = G_OBJECT_CLASS (class); GTypeModuleClass *type_module_class = G_TYPE_MODULE_CLASS (class); object_class->finalize = g_io_module_finalize; type_module_class->load = g_io_module_load_module; type_module_class->unload = g_io_module_unload_module; } static void g_io_module_init (GIOModule *module) { } static void g_io_module_finalize (GObject *object) { GIOModule *module = G_IO_MODULE (object); g_free (module->filename); G_OBJECT_CLASS (g_io_module_parent_class)->finalize (object); } static gboolean g_io_module_load_module (GTypeModule *gmodule) { GIOModule *module = G_IO_MODULE (gmodule); if (!module->filename) { g_warning ("GIOModule path not set"); return FALSE; } module->library = g_module_open (module->filename, G_MODULE_BIND_LAZY | G_MODULE_BIND_LOCAL); if (!module->library) { g_printerr ("%s\n", g_module_error ()); return FALSE; } /* Make sure that the loaded library contains the required methods */ if (! g_module_symbol (module->library, "g_io_module_load", (gpointer) &module->load) || ! g_module_symbol (module->library, "g_io_module_unload", (gpointer) &module->unload)) { g_printerr ("%s\n", g_module_error ()); g_module_close (module->library); return FALSE; } /* Initialize the loaded module */ module->load (module); return TRUE; } static void g_io_module_unload_module (GTypeModule *gmodule) { GIOModule *module = G_IO_MODULE (gmodule); module->unload (module); g_module_close (module->library); module->library = NULL; module->load = NULL; module->unload = NULL; } /** * g_io_module_new: * @filename: filename of the shared library module. * * Creates a new GIOModule that will load the specific * shared library when in use. * * Returns: a #GIOModule from given @filename, * or %NULL on error. **/ GIOModule * g_io_module_new (const gchar *filename) { GIOModule *module; g_return_val_if_fail (filename != NULL, NULL); module = g_object_new (G_IO_TYPE_MODULE, NULL); module->filename = g_strdup (filename); return module; } static gboolean is_valid_module_name (const gchar *basename) { #if !defined(G_OS_WIN32) && !defined(G_WITH_CYGWIN) return g_str_has_prefix (basename, "lib") && g_str_has_suffix (basename, ".so"); #else return g_str_has_suffix (basename, ".dll"); #endif } /** * g_io_modules_load_all_in_directory: * @dirname: pathname for a directory containing modules to load. * * Loads all the modules in the specified directory. * * Returns: a list of #GIOModules loaded from the directory, * All the modules are loaded into memory, if you want to * unload them (enabling on-demand loading) you must call * g_type_module_unuse() on all the modules. Free the list * with g_list_free(). **/ GList * g_io_modules_load_all_in_directory (const char *dirname) { const gchar *name; GDir *dir; GList *modules; if (!g_module_supported ()) return NULL; dir = g_dir_open (dirname, 0, NULL); if (!dir) return NULL; modules = NULL; while ((name = g_dir_read_name (dir))) { if (is_valid_module_name (name)) { GIOModule *module; gchar *path; path = g_build_filename (dirname, name, NULL); module = g_io_module_new (path); if (!g_type_module_use (G_TYPE_MODULE (module))) { g_printerr ("Failed to load module: %s\n", path); g_object_unref (module); g_free (path); continue; } g_free (path); modules = g_list_prepend (modules, module); } } g_dir_close (dir); return modules; } G_LOCK_DEFINE_STATIC (loaded_dirs); extern GType _g_inotify_directory_monitor_get_type (void); extern GType _g_inotify_file_monitor_get_type (void); extern GType _g_unix_volume_monitor_get_type (void); extern GType _g_local_vfs_get_type (void); extern GType g_win32_directory_monitor_get_type (void); void _g_io_modules_ensure_loaded (void) { GList *modules, *l; static gboolean loaded_dirs = FALSE; GIOExtensionPoint *ep; G_LOCK (loaded_dirs); if (!loaded_dirs) { loaded_dirs = TRUE; #ifdef G_OS_UNIX ep = g_io_extension_point_register (G_DESKTOP_APP_INFO_LOOKUP_EXTENSION_POINT_NAME); g_io_extension_point_set_required_type (ep, G_TYPE_DESKTOP_APP_INFO_LOOKUP); #endif ep = g_io_extension_point_register (G_LOCAL_DIRECTORY_MONITOR_EXTENSION_POINT_NAME); g_io_extension_point_set_required_type (ep, G_TYPE_LOCAL_DIRECTORY_MONITOR); ep = g_io_extension_point_register (G_LOCAL_FILE_MONITOR_EXTENSION_POINT_NAME); g_io_extension_point_set_required_type (ep, G_TYPE_LOCAL_FILE_MONITOR); ep = g_io_extension_point_register (G_VOLUME_MONITOR_EXTENSION_POINT_NAME); g_io_extension_point_set_required_type (ep, G_TYPE_VOLUME_MONITOR); ep = g_io_extension_point_register (G_NATIVE_VOLUME_MONITOR_EXTENSION_POINT_NAME); g_io_extension_point_set_required_type (ep, G_TYPE_NATIVE_VOLUME_MONITOR); ep = g_io_extension_point_register (G_VFS_EXTENSION_POINT_NAME); g_io_extension_point_set_required_type (ep, G_TYPE_VFS); modules = g_io_modules_load_all_in_directory (GIO_MODULE_DIR); /* Initialize types from built-in "modules" */ #if defined(HAVE_SYS_INOTIFY_H) || defined(HAVE_LINUX_INOTIFY_H) _g_inotify_directory_monitor_get_type (); _g_inotify_file_monitor_get_type (); #endif #ifdef G_OS_WIN32 g_win32_directory_monitor_get_type (); #endif #ifdef G_OS_UNIX _g_unix_volume_monitor_get_type (); #endif _g_local_vfs_get_type (); for (l = modules; l != NULL; l = l->next) g_type_module_unuse (G_TYPE_MODULE (l->data)); g_list_free (modules); } G_UNLOCK (loaded_dirs); } struct _GIOExtension { char *name; GType type; gint priority; }; struct _GIOExtensionPoint { GType required_type; char *name; GList *extensions; }; static GHashTable *extension_points = NULL; G_LOCK_DEFINE_STATIC(extension_points); static void g_io_extension_point_free (GIOExtensionPoint *ep) { g_free (ep->name); g_free (ep); } /** * g_io_extension_point_register: * @name: The name of the extension point * * Registers an extension point. * * Returns: the new #GIOExtensionPoint. This object is owned by GIO * and should not be freed */ GIOExtensionPoint * g_io_extension_point_register (const char *name) { GIOExtensionPoint *ep; G_LOCK (extension_points); if (extension_points == NULL) extension_points = g_hash_table_new_full (g_str_hash, g_str_equal, NULL, (GDestroyNotify)g_io_extension_point_free); if (g_hash_table_lookup (extension_points, name) != NULL) { g_warning ("Extension point %s registered multiple times", name); G_UNLOCK (extension_points); return NULL; } ep = g_new0 (GIOExtensionPoint, 1); ep->name = g_strdup (name); g_hash_table_insert (extension_points, ep->name, ep); G_UNLOCK (extension_points); return ep; } /** * g_io_extension_point_lookup: * @name: the name of the extension point * * Looks up an existing extension point. * * Returns: the #GIOExtensionPoint, or %NULL if there is no * registered extension point with the given name */ GIOExtensionPoint * g_io_extension_point_lookup (const char *name) { GIOExtensionPoint *ep; G_LOCK (extension_points); ep = NULL; if (extension_points != NULL) ep = g_hash_table_lookup (extension_points, name); G_UNLOCK (extension_points); return ep; } /** * g_io_extension_point_set_required_type: * @extension_point: a #GIOExtensionPoint * @type: the #GType to require * * Sets the required type for @extension_point to @type. * All implementations must henceforth have this type. */ void g_io_extension_point_set_required_type (GIOExtensionPoint *extension_point, GType type) { extension_point->required_type = type; } /** * g_io_extension_point_get_required_type: * @extension_point: a #GIOExtensionPoint * * Gets the required type for @extension_point. * * Returns: the #GType that all implementations must have, * or #G_TYPE_INVALID if the extension point has no required type */ GType g_io_extension_point_get_required_type (GIOExtensionPoint *extension_point) { return extension_point->required_type; } /** * g_io_extension_point_get_extensions: * @extension_point: a #GIOExtensionPoint * * Gets a list of all extensions that implement this extension point. * The list is sorted by priority, beginning with the highest priority. * * Returns: a #GList of #GIOExtensions. The list is owned by * GIO and should not be modified */ GList * g_io_extension_point_get_extensions (GIOExtensionPoint *extension_point) { return extension_point->extensions; } /** * g_io_extension_point_get_extension_by_name: * @extension_point: a #GIOExtensionPoint * @name: the name of the extension to get * * Finds a #GIOExtension for an extension point by name. * * Returns: the #GIOExtension for @extension_point that has the * given name, or %NULL if there is no extension with that name */ GIOExtension * g_io_extension_point_get_extension_by_name (GIOExtensionPoint *extension_point, const char *name) { GList *l; for (l = extension_point->extensions; l != NULL; l = l->next) { GIOExtension *e = l->data; if (e->name != NULL && strcmp (e->name, name) == 0) return e; } return NULL; } static gint extension_prio_compare (gconstpointer a, gconstpointer b) { const GIOExtension *extension_a = a, *extension_b = b; return extension_b->priority - extension_a->priority; } /** * g_io_extension_point_implement: * @extension_point_name: the name of the extension point * @type: the #GType to register as extension * @extension_name: the name for the extension * @priority: the priority for the extension * * Registers @type as extension for the extension point with name * @extension_point_name. * * If @type has already been registered as an extension for this * extension point, the existing #GIOExtension object is returned. * * Returns: a #GIOExtension object for #GType */ GIOExtension * g_io_extension_point_implement (const char *extension_point_name, GType type, const char *extension_name, gint priority) { GIOExtensionPoint *extension_point; GIOExtension *extension; GList *l; g_return_val_if_fail (extension_point_name != NULL, NULL); extension_point = g_io_extension_point_lookup (extension_point_name); if (extension_point == NULL) { g_warning ("Tried to implement non-registered extension point %s", extension_point_name); return NULL; } if (extension_point->required_type != 0 && !g_type_is_a (type, extension_point->required_type)) { g_warning ("Tried to register an extension of the type %s to extension point %s. " "Expected type is %s.", g_type_name (type), extension_point_name, g_type_name (extension_point->required_type)); return NULL; } /* Its safe to register the same type multiple times */ for (l = extension_point->extensions; l != NULL; l = l->next) { extension = l->data; if (extension->type == type) return extension; } extension = g_slice_new0 (GIOExtension); extension->type = type; extension->name = g_strdup (extension_name); extension->priority = priority; extension_point->extensions = g_list_insert_sorted (extension_point->extensions, extension, extension_prio_compare); return extension; } /** * g_io_extension_ref_class: * @extension: a #GIOExtension * * Gets a reference to the class for the type that is * associated with @extension. * * Returns: the #GTypeClass for the type of @extension */ GTypeClass * g_io_extension_ref_class (GIOExtension *extension) { return g_type_class_ref (extension->type); } /** * g_io_extension_get_type: * @extension: a #GIOExtension * * Gets the type associated with @extension. * * Returns: the type of @extension */ GType g_io_extension_get_type (GIOExtension *extension) { return extension->type; } /** * g_io_extension_get_name: * @extension: a #GIOExtension * * Gets the name under which @extension was registered. * * Note that the same type may be registered as extension * for multiple extension points, under different names. * * Returns: the name of @extension. */ const char * g_io_extension_get_name (GIOExtension *extension) { return extension->name; } /** * g_io_extension_get_priority: * @extension: a #GIOExtension * * Gets the priority with which @extension was registered. * * Returns: the priority of @extension */ gint g_io_extension_get_priority (GIOExtension *extension) { return extension->priority; } #define __G_IO_MODULE_C__ #include "gioaliasdef.c"