/* * Copyright © 2011 Canonical Ltd. * * 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 * licence, 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: Ryan Lortie */ #include "gmenuproxy.h" #include "gmenumodel.h" /* Prelude {{{1 */ /** * SECTION:gmenuproxy * @title: GMenuProxy * @short_description: A D-Bus GMenuModel implementation * @see_also: GMenuModel Exporter * * #GMenuProxy is an implementation of #GMenuModel that can be used * as a proxy for a menu model that is exported over D-Bus with * g_menu_model_dbus_export_start(). */ /* * There are 3 main (quasi-)classes involved here: * * - GMenuProxyPath * - GMenuProxyGroup * - GMenuProxy * * Each of these classes exists as a parameterised singleton keyed to a * particular thing: * * - GMenuProxyPath represents a D-Bus object path on a particular * unique bus name on a particular GDBusConnection. * * - GMenuProxyGroup represents a particular group on a particular * GMenuProxyPath. * * - GMenuProxy represents a particular menu within a particular * GMenuProxyGroup. * * There are also two (and a half) utility structs: * * - PathIdentifier and ConstPathIdentifier * - GMenuProxyItem * * PathIdentifier is the triplet of (GDBusConnection, unique name, * object path) that uniquely identifies a particular GMenuProxyPath. * It holds ownership on each of these things, so we have a * ConstPathIdentifier variant that does not. * * We have a 3-level hierarchy of hashtables: * * - a global hashtable (g_menu_proxy_paths) maps from PathIdentifier * to GMenuProxyPath * * - each GMenuProxyPath has a hashtable mapping from guint (group * number) to GMenuProxyGroup * * - each GMenuProxyGroup has a hashtable mapping from guint (menu * number) to GMenuProxy. * * In this way, each quintuplet of (connection, bus name, object path, * group id, menu id) maps to a single GMenuProxy instance that can be * located via 3 hashtable lookups. * * All of the 3 classes are refcounted (GMenuProxyPath and * GMenuProxyGroup manually, and GMenuProxy by virtue of being a * GObject). The hashtables do not hold references -- rather, when the * last reference is dropped, the object is removed from the hashtable. * * The hard references go in the other direction: GMenuProxy is created * as the user requests it and only exists as long as the user holds a * reference on it. GMenuProxy holds a reference on the GMenuProxyGroup * from which it came. GMenuProxyGroup holds a reference on * GMenuProxyPath. * * In addition to refcounts, each object has an 'active' variable (ints * for GMenuProxyPath and GMenuProxyGroup, boolean for GMenuProxy). * * - GMenuProxy is inactive when created and becomes active only when * first queried for information. This prevents extra work from * happening just by someone acquiring a GMenuProxy (and not * actually trying to display it yet). * * - The active count on GMenuProxyGroup is equal to the number of * GMenuProxy instances in that group that are active. When the * active count transitions from 0 to 1, the group calls the 'Start' * method on the service to begin monitoring that group. When it * drops from 1 to 0, the group calls the 'End' method to stop * monitoring. * * - The active count on GMenuProxyPath is equal to the number of * GMenuProxyGroup instances on that path with a non-zero active * count. When the active count transitions from 0 to 1, the path * sets up a signal subscription to monitor any changes. The signal * subscription is taken down when the active count transitions from * 1 to 0. * * When active, GMenuProxyPath gets incoming signals when changes occur. * If the change signal mentions a group for which we currently have an * active GMenuProxyGroup, the change signal is passed along to that * group. If the group is inactive, the change signal is ignored. * * Most of the "work" occurs in GMenuProxyGroup. In addition to the * hashtable of GMenuProxy instances, it keeps a hashtable of the actual * menu contents, each encoded as GSequence of GMenuProxyItem. It * initially populates this table with the results of the "Start" method * call and then updates it according to incoming change signals. If * the change signal mentions a menu for which we current have an active * GMenuProxy, the change signal is passed along to that proxy. If the * proxy is inactive, the change signal is ignored. * * GMenuProxyItem is just a pair of hashtables, one for the attributes * and one for the links of the item. Both map strings to GVariant * instances. In the case of links, the GVariant has type '(uu)' and is * turned into a GMenuProxy at the point that the user pulls it through * the API. * * Following the "empty is the same as non-existent" rule, the hashtable * of GSequence of GMenuProxyItem holds NULL for empty menus. * * GMenuProxy contains very little functionality of its own. It holds a * (weak) reference to the GSequence of GMenuProxyItem contained in the * GMenuProxyGroup. It uses this GSequence to implement the GMenuModel * interface. It also emits the "items-changed" signal if it is active * and it was told that the contents of the GSequence changed. */ typedef struct _GMenuProxyGroup GMenuProxyGroup; typedef struct _GMenuProxyPath GMenuProxyPath; static void g_menu_proxy_group_changed (GMenuProxyGroup *group, guint menu_id, gint position, gint removed, GVariant *added); static void g_menu_proxy_changed (GMenuProxy *proxy, GSequence *items, gint position, gint removed, gint added); static GMenuProxyGroup * g_menu_proxy_group_get_from_path (GMenuProxyPath *path, guint group_id); static GMenuProxy * g_menu_proxy_get_from_group (GMenuProxyGroup *group, guint menu_id); /* PathIdentifier {{{1 */ typedef struct { GDBusConnection *connection; gchar *bus_name; gchar *object_path; } PathIdentifier; typedef const struct { GDBusConnection *connection; const gchar *bus_name; const gchar *object_path; } ConstPathIdentifier; static guint path_identifier_hash (gconstpointer data) { ConstPathIdentifier *id = data; return g_str_hash (id->object_path); } static gboolean path_identifier_equal (gconstpointer a, gconstpointer b) { ConstPathIdentifier *id_a = a; ConstPathIdentifier *id_b = b; return id_a->connection == id_b->connection && g_str_equal (id_a->bus_name, id_b->bus_name) && g_str_equal (id_a->object_path, id_b->object_path); } static void path_identifier_free (PathIdentifier *id) { g_object_unref (id->connection); g_free (id->bus_name); g_free (id->object_path); g_slice_free (PathIdentifier, id); } static PathIdentifier * path_identifier_new (ConstPathIdentifier *cid) { PathIdentifier *id; id = g_slice_new (PathIdentifier); id->connection = g_object_ref (cid->connection); id->bus_name = g_strdup (cid->bus_name); id->object_path = g_strdup (cid->object_path); return id; } /* GMenuProxyPath {{{1 */ struct _GMenuProxyPath { PathIdentifier *id; gint ref_count; GHashTable *groups; gint active; guint watch_id; }; static GHashTable *g_menu_proxy_paths; static GMenuProxyPath * g_menu_proxy_path_ref (GMenuProxyPath *path) { path->ref_count++; return path; } static void g_menu_proxy_path_unref (GMenuProxyPath *path) { if (--path->ref_count == 0) { g_hash_table_remove (g_menu_proxy_paths, path->id); g_hash_table_unref (path->groups); path_identifier_free (path->id); g_slice_free (GMenuProxyPath, path); } } static void g_menu_proxy_path_signal (GDBusConnection *connection, const gchar *sender_name, const gchar *object_path, const gchar *interface_name, const gchar *signal_name, GVariant *parameters, gpointer user_data) { GMenuProxyPath *path = user_data; GVariantIter *iter; guint group_id; guint menu_id; guint position; guint removes; GVariant *adds; if (!g_variant_is_of_type (parameters, G_VARIANT_TYPE ("(a(uuuuaa{sv}))"))) return; g_variant_get (parameters, "(a(uuuuaa{sv}))", &iter); while (g_variant_iter_loop (iter, "(uuuu@aa{sv})", &group_id, &menu_id, &position, &removes, &adds)) { GMenuProxyGroup *group; group = g_hash_table_lookup (path->groups, GINT_TO_POINTER (group_id)); if (group != NULL) g_menu_proxy_group_changed (group, menu_id, position, removes, adds); } g_variant_iter_free (iter); } static void g_menu_proxy_path_activate (GMenuProxyPath *path) { if (path->active++ == 0) path->watch_id = g_dbus_connection_signal_subscribe (path->id->connection, path->id->bus_name, "org.gtk.Menus", "Changed", path->id->object_path, NULL, G_DBUS_SIGNAL_FLAGS_NONE, g_menu_proxy_path_signal, path, NULL); } static void g_menu_proxy_path_deactivate (GMenuProxyPath *path) { if (--path->active == 0) g_dbus_connection_signal_unsubscribe (path->id->connection, path->watch_id); } static GMenuProxyPath * g_menu_proxy_path_get (GDBusConnection *connection, const gchar *bus_name, const gchar *object_path) { ConstPathIdentifier cid = { connection, bus_name, object_path }; GMenuProxyPath *path; if (g_menu_proxy_paths == NULL) g_menu_proxy_paths = g_hash_table_new (path_identifier_hash, path_identifier_equal); path = g_hash_table_lookup (g_menu_proxy_paths, &cid); if (path == NULL) { path = g_slice_new (GMenuProxyPath); path->id = path_identifier_new (&cid); path->groups = g_hash_table_new (NULL, NULL); path->ref_count = 0; path->active = 0; g_hash_table_insert (g_menu_proxy_paths, path->id, path); } return g_menu_proxy_path_ref (path); } /* GMenuProxyGroup, GMenuProxyItem {{{1 */ typedef enum { GROUP_OFFLINE, GROUP_PENDING, GROUP_ONLINE } GroupStatus; struct _GMenuProxyGroup { GMenuProxyPath *path; guint id; GHashTable *proxies; /* uint -> unowned GMenuProxy */ GHashTable *menus; /* uint -> owned GSequence */ gint ref_count; GroupStatus state; gint active; }; typedef struct { GHashTable *attributes; GHashTable *links; } GMenuProxyItem; static GMenuProxyGroup * g_menu_proxy_group_ref (GMenuProxyGroup *group) { group->ref_count++; return group; } static void g_menu_proxy_group_unref (GMenuProxyGroup *group) { if (--group->ref_count == 0) { g_assert (group->state == GROUP_OFFLINE); g_assert (group->active == 0); g_hash_table_remove (group->path->groups, GINT_TO_POINTER (group->id)); g_hash_table_unref (group->proxies); g_menu_proxy_path_unref (group->path); g_slice_free (GMenuProxyGroup, group); } } static void g_menu_proxy_item_free (gpointer data) { GMenuProxyItem *item = data; g_hash_table_unref (item->attributes); g_hash_table_unref (item->links); g_slice_free (GMenuProxyItem, item); } static GMenuProxyItem * g_menu_proxy_group_create_item (GVariant *description) { GMenuProxyItem *item; GVariantIter iter; const gchar *key; GVariant *value; item = g_slice_new (GMenuProxyItem); item->attributes = g_hash_table_new_full (g_str_hash, g_str_equal, g_free, (GDestroyNotify) g_variant_unref); item->links = g_hash_table_new_full (g_str_hash, g_str_equal, g_free, (GDestroyNotify) g_variant_unref); g_variant_iter_init (&iter, description); while (g_variant_iter_loop (&iter, "{&sv}", &key, &value)) if (key[0] == ':') /* key + 1 to skip the ':' */ g_hash_table_insert (item->links, g_strdup (key + 1), g_variant_ref (value)); else g_hash_table_insert (item->attributes, g_strdup (key), g_variant_ref (value)); return item; } /* * GMenuProxyGroup can be in three states: * * OFFLINE: not subscribed to this group * PENDING: we made the call to subscribe to this group, but the result * has not come back yet * ONLINE: we are fully subscribed * * We can get into some nasty situations where we make a call due to an * activation request but receive a deactivation request before the call * returns. If another activation request occurs then we could risk * sending a Start request even though one is already in progress. For * this reason, we have to carefully consider what to do in each of the * three states for each of the following situations: * * - activation requested * - deactivation requested * - Start call finishes * * To simplify things a bit, we do not have a callback for the Stop * call. We just send it and assume that it takes effect immediately. * * Activation requested: * OFFLINE: make the Start call and transition to PENDING * PENDING: do nothing -- call is already in progress. * ONLINE: this should not be possible * * Deactivation requested: * OFFLINE: this should not be possible * PENDING: do nothing -- handle it when the Start call finishes * ONLINE: send the Stop call and move to OFFLINE immediately * * Start call finishes: * OFFLINE: this should not be possible * PENDING: * If we should be active (ie: active count > 0): move to ONLINE * If not: send Stop call and move to OFFLINE immediately * ONLINE: this should not be possible * * We have to take care with regards to signal subscriptions (ie: * activation of the GMenuProxyPath). The signal subscription is always * established when transitioning from OFFLINE to PENDING and taken down * when transitioning to OFFLINE (from either PENDING or ONLINE). * * Since there are two places where we transition to OFFLINE, we split * that code out into a separate function. */ static void g_menu_proxy_group_go_offline (GMenuProxyGroup *group) { g_menu_proxy_path_deactivate (group->path); g_dbus_connection_call (group->path->id->connection, group->path->id->bus_name, group->path->id->object_path, "org.gtk.Menus", "End", g_variant_new_parsed ("([ %u ],)", group->id), NULL, G_DBUS_CALL_FLAGS_NONE, -1, NULL, NULL, NULL); group->state = GROUP_OFFLINE; } static void g_menu_proxy_group_start_ready (GObject *source_object, GAsyncResult *result, gpointer user_data) { GDBusConnection *connection = G_DBUS_CONNECTION (source_object); GMenuProxyGroup *group = user_data; GVariant *reply; g_assert (group->state == GROUP_PENDING); reply = g_dbus_connection_call_finish (connection, result, NULL); if (group->active) { group->state = GROUP_ONLINE; /* If we receive no reply, just act like we got an empty reply. */ if (reply) { GVariantIter *iter; GVariant *items; guint group_id; guint menu_id; g_variant_get (reply, "(a(uuaa{sv}))", &iter); while (g_variant_iter_loop (iter, "(uu@aa{sv})", &group_id, &menu_id, &items)) if (group_id == group->id) g_menu_proxy_group_changed (group, menu_id, 0, 0, items); g_variant_iter_free (iter); } } else g_menu_proxy_group_go_offline (group); if (reply) g_variant_unref (reply); g_menu_proxy_group_unref (group); } static void g_menu_proxy_group_activate (GMenuProxyGroup *group) { if (group->active++ == 0) { g_assert (group->state != GROUP_ONLINE); if (group->state == GROUP_OFFLINE) { g_menu_proxy_path_activate (group->path); g_dbus_connection_call (group->path->id->connection, group->path->id->bus_name, group->path->id->object_path, "org.gtk.Menus", "Start", g_variant_new_parsed ("([ %u ],)", group->id), G_VARIANT_TYPE ("(a(uuaa{sv}))"), G_DBUS_CALL_FLAGS_NONE, -1, NULL, g_menu_proxy_group_start_ready, g_menu_proxy_group_ref (group)); group->state = GROUP_PENDING; } } } static void g_menu_proxy_group_deactivate (GMenuProxyGroup *group) { if (--group->active == 0) { g_assert (group->state != GROUP_OFFLINE); if (group->state == GROUP_ONLINE) { /* We are here because nobody is watching, so just free * everything and don't bother with the notifications. */ g_hash_table_remove_all (group->menus); g_menu_proxy_group_go_offline (group); } } } static void g_menu_proxy_group_changed (GMenuProxyGroup *group, guint menu_id, gint position, gint removed, GVariant *added) { GSequenceIter *point; GVariantIter iter; GMenuProxy *proxy; GSequence *items; GVariant *item; gint n_added; /* We could have signals coming to us when we're not active (due to * some other process having subscribed to this group) or when we're * pending. In both of those cases, we want to ignore the signal * since we'll get our own information when we call "Start" for * ourselves. */ if (group->state != GROUP_ONLINE) return; items = g_hash_table_lookup (group->menus, GINT_TO_POINTER (menu_id)); if (items == NULL) { items = g_sequence_new (g_menu_proxy_item_free); g_hash_table_insert (group->menus, GINT_TO_POINTER (menu_id), items); } point = g_sequence_get_iter_at_pos (items, position + removed); g_return_if_fail (point != NULL); if (removed) { GSequenceIter *start; start = g_sequence_get_iter_at_pos (items, position); g_sequence_remove_range (start, point); } n_added = g_variant_iter_init (&iter, added); while (g_variant_iter_loop (&iter, "@a{sv}", &item)) g_sequence_insert_before (point, g_menu_proxy_group_create_item (item)); if (g_sequence_get_length (items) == 0) { g_hash_table_remove (group->menus, GINT_TO_POINTER (menu_id)); items = NULL; } if ((proxy = g_hash_table_lookup (group->proxies, GINT_TO_POINTER (menu_id)))) g_menu_proxy_changed (proxy, items, position, removed, n_added); } static GMenuProxyGroup * g_menu_proxy_group_get_from_path (GMenuProxyPath *path, guint group_id) { GMenuProxyGroup *group; group = g_hash_table_lookup (path->groups, GINT_TO_POINTER (group_id)); if (group == NULL) { group = g_slice_new (GMenuProxyGroup); group->path = g_menu_proxy_path_ref (path); group->id = group_id; group->proxies = g_hash_table_new (NULL, NULL); group->menus = g_hash_table_new_full (NULL, NULL, NULL, (GDestroyNotify) g_sequence_free); group->state = GROUP_OFFLINE; group->active = 0; group->ref_count = 0; g_hash_table_insert (path->groups, GINT_TO_POINTER (group->id), group); } return g_menu_proxy_group_ref (group); } static GMenuProxyGroup * g_menu_proxy_group_get (GDBusConnection *connection, const gchar *bus_name, const gchar *object_path, guint group_id) { GMenuProxyGroup *group; GMenuProxyPath *path; path = g_menu_proxy_path_get (connection, bus_name, object_path); group = g_menu_proxy_group_get_from_path (path, group_id); g_menu_proxy_path_unref (path); return group; } /* GMenuProxy {{{1 */ typedef GMenuModelClass GMenuProxyClass; struct _GMenuProxy { GMenuModel parent; GMenuProxyGroup *group; guint id; GSequence *items; /* unowned */ gboolean active; }; G_DEFINE_TYPE (GMenuProxy, g_menu_proxy, G_TYPE_MENU_MODEL) static gboolean g_menu_proxy_is_mutable (GMenuModel *model) { return TRUE; } static gint g_menu_proxy_get_n_items (GMenuModel *model) { GMenuProxy *proxy = G_MENU_PROXY (model); if (!proxy->active) { g_menu_proxy_group_activate (proxy->group); proxy->active = TRUE; } return proxy->items ? g_sequence_get_length (proxy->items) : 0; } static void g_menu_proxy_get_item_attributes (GMenuModel *model, gint item_index, GHashTable **table) { GMenuProxy *proxy = G_MENU_PROXY (model); GMenuProxyItem *item; GSequenceIter *iter; g_return_if_fail (proxy->active); g_return_if_fail (proxy->items); iter = g_sequence_get_iter_at_pos (proxy->items, item_index); g_return_if_fail (iter); item = g_sequence_get (iter); g_return_if_fail (item); *table = g_hash_table_ref (item->attributes); } static void g_menu_proxy_get_item_links (GMenuModel *model, gint item_index, GHashTable **table) { GMenuProxy *proxy = G_MENU_PROXY (model); GMenuProxyItem *item; GSequenceIter *iter; g_return_if_fail (proxy->active); g_return_if_fail (proxy->items); iter = g_sequence_get_iter_at_pos (proxy->items, item_index); g_return_if_fail (iter); item = g_sequence_get (iter); g_return_if_fail (item); *table = g_hash_table_new_full (g_str_hash, g_str_equal, g_free, g_object_unref); { GHashTableIter tmp; gpointer key; gpointer value; g_hash_table_iter_init (&tmp, item->links); while (g_hash_table_iter_next (&tmp, &key, &value)) { if (g_variant_is_of_type (value, G_VARIANT_TYPE ("(uu)"))) { guint group_id, menu_id; GMenuProxyGroup *group; GMenuProxy *link; g_variant_get (value, "(uu)", &group_id, &menu_id); /* save the hash lookup in a relatively common case */ if (proxy->group->id != group_id) group = g_menu_proxy_group_get_from_path (proxy->group->path, group_id); else group = g_menu_proxy_group_ref (proxy->group); link = g_menu_proxy_get_from_group (group, menu_id); g_hash_table_insert (*table, g_strdup (key), link); g_menu_proxy_group_unref (group); } } } } static void g_menu_proxy_finalize (GObject *object) { GMenuProxy *proxy = G_MENU_PROXY (object); if (proxy->active) g_menu_proxy_group_deactivate (proxy->group); g_hash_table_remove (proxy->group->proxies, GINT_TO_POINTER (proxy->id)); g_menu_proxy_group_unref (proxy->group); G_OBJECT_CLASS (g_menu_proxy_parent_class) ->finalize (object); } static void g_menu_proxy_init (GMenuProxy *proxy) { } static void g_menu_proxy_class_init (GMenuProxyClass *class) { GObjectClass *object_class = G_OBJECT_CLASS (class); class->is_mutable = g_menu_proxy_is_mutable; class->get_n_items = g_menu_proxy_get_n_items; class->get_item_attributes = g_menu_proxy_get_item_attributes; class->get_item_links = g_menu_proxy_get_item_links; object_class->finalize = g_menu_proxy_finalize; } static void g_menu_proxy_changed (GMenuProxy *proxy, GSequence *items, gint position, gint removed, gint added) { proxy->items = items; if (proxy->active && (removed || added)) g_menu_model_items_changed (G_MENU_MODEL (proxy), position, removed, added); } static GMenuProxy * g_menu_proxy_get_from_group (GMenuProxyGroup *group, guint menu_id) { GMenuProxy *proxy; proxy = g_hash_table_lookup (group->proxies, GINT_TO_POINTER (menu_id)); if (proxy) g_object_ref (proxy); if (proxy == NULL) { proxy = g_object_new (G_TYPE_MENU_PROXY, NULL); proxy->items = g_hash_table_lookup (group->menus, GINT_TO_POINTER (menu_id)); g_hash_table_insert (group->proxies, GINT_TO_POINTER (menu_id), proxy); proxy->group = g_menu_proxy_group_ref (group); proxy->id = menu_id; } return proxy; } /** * g_menu_proxy_get: * @connection: a #GDBusConnection * @bus_name: the bus name which exports the menu model * @object_path: the object path at which the menu model is exported * * Obtains a #GMenuProxy for the menu model which is exported * at the given @bus_name and @object_path. * * Returns: (transfer full): a #GMenuProxy object. Free with g_object_unref(). */ GMenuProxy * g_menu_proxy_get (GDBusConnection *connection, const gchar *bus_name, const gchar *object_path) { GMenuProxyGroup *group; GMenuProxy *proxy; group = g_menu_proxy_group_get (connection, bus_name, object_path, 0); proxy = g_menu_proxy_get_from_group (group, 0); g_menu_proxy_group_unref (group); return proxy; } static void dump_proxy (gpointer key, gpointer value, gpointer data) { GMenuProxy *proxy = value; g_print (" menu %d refcount %d active %d\n", proxy->id, G_OBJECT (proxy)->ref_count, proxy->active); } static void dump_group (gpointer key, gpointer value, gpointer data) { GMenuProxyGroup *group = value; g_print (" group %d refcount %d state %d active %d\n", group->id, group->ref_count, group->state, group->active); g_hash_table_foreach (group->proxies, dump_proxy, NULL); } static void dump_path (gpointer key, gpointer value, gpointer data) { PathIdentifier *pid = key; GMenuProxyPath *path = value; g_print ("%s active %d\n", pid->object_path, path->active); g_hash_table_foreach (path->groups, dump_group, NULL); } void g_menu_proxy_dump (void) { g_hash_table_foreach (g_menu_proxy_paths, dump_path, NULL); } /* Epilogue {{{1 */ /* vim:set foldmethod=marker: */