Attachment 51802 Details for Bug 23846 – Don't subscribe to all D-Bus signals but only those the user is interested in

[patch] Don't subscribe to all D-Bus signals but only those the user is interested in

0001-Don-t-subscribe-to-all-D-Bus-signals-but-only-those-.patch (text/plain), 11.06 KB, created by Simon McVittie on 2011-09-30 09:04:11 UTC

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Creator: Simon McVittie

Created: 2011-09-30 09:04:11 UTC

Size: 11.06 KB

patch

obsolete

>From dca8fb6e3bdf1f507bcd00cf830b98afd61428fd Mon Sep 17 00:00:00 2001
>From: Simon McVittie <simon.mcvittie@collabora.co.uk>
>Date: Thu, 29 Sep 2011 18:25:09 +0100
>Subject: [PATCH] Don't subscribe to all D-Bus signals but only those the user
> is interested in
>
>See NB#189509, NB#141956, https://bugs.freedesktop.org/show_bug.cgi?id=23846
>
>[Adjusted to apply to dbus-glib 0.96 -smcv]
>
>Bug: https://bugs.freedesktop.org/show_bug.cgi?id=23846
>Bug-NB: NB#189509, NB#141956
>---
> dbus/dbus-gproxy.c |  227 +++++++++++++++++++++++++++++++++++++++++++---------
> 1 files changed, 188 insertions(+), 39 deletions(-)
>
>diff --git a/dbus/dbus-gproxy.c b/dbus/dbus-gproxy.c
>index 16ee119..4ae5ecc 100644
>--- a/dbus/dbus-gproxy.c
>+++ b/dbus/dbus-gproxy.c
>@@ -121,6 +121,20 @@ typedef struct
> {
>   GSList *proxies; /**< The list of proxies */
> 
>+  /**
>+   * The application can connect several callbacks for the same quadruplet
>+   * (name, path, interface, member). The callbacks can be on the same
>+   * DBusGProxy or on several ones. In both cases, we add only one match rule
>+   * to dbus-daemon. We need to count how many callbacks are registered so we
>+   * know when to add or remove a match rule to dbus-daemon.
>+   *
>+   * signal_subscriptions counts the number of callbacks registered for each
>+   * DBusGProxy.
>+   *
>+   * gchar *signal_name -> GHashTable* of (DBusGProxy *proxy -> guint count)
>+   */
>+  GHashTable *signal_subscriptions;
>+
>   char name[4]; /**< name (empty string for none), nul byte,
>                  *   path, nul byte,
>                  *   interface, nul byte
>@@ -467,6 +481,7 @@ g_proxy_list_new (DBusGProxy *first_proxy)
>                                                priv->path,
>                                                priv->interface);
>   list->proxies = NULL;
>+  list->signal_subscriptions = NULL;
> 
>   return list;
> }
>@@ -477,23 +492,35 @@ g_proxy_list_free (DBusGProxyList *list)
>   /* we don't hold a reference to the proxies in the list,
>    * as they ref the GProxyManager
>    */
>-  g_slist_free (list->proxies);  
>+  g_slist_free (list->proxies);
>+  if (list->signal_subscriptions != NULL)
>+    {
>+      g_hash_table_destroy (list->signal_subscriptions);
>+    }
> 
>   g_free (list);
> }
> 
> static char*
>-g_proxy_get_signal_match_rule (DBusGProxy *proxy)
>+g_proxy_get_signal_match_rule (DBusGProxy *proxy, const gchar *signal_name)
> {
>   DBusGProxyPrivate *priv = DBUS_G_PROXY_GET_PRIVATE(proxy);
>   /* FIXME Escaping is required here */
>-  
>+
>+  g_assert (signal_name != NULL);
>   if (priv->name)
>-    return g_strdup_printf ("type='signal',sender='%s',path='%s',interface='%s'",
>-                            priv->name, priv->path, priv->interface);
>+    {
>+      return g_strdup_printf ("type='signal',sender='%s',path='%s',"
>+                              "interface='%s',member='%s'",
>+                              priv->name, priv->path, priv->interface,
>+                              signal_name);
>+    }
>   else
>-    return g_strdup_printf ("type='signal',path='%s',interface='%s'",
>-                            priv->path, priv->interface);
>+    {
>+      return g_strdup_printf ("type='signal',path='%s',interface='%s',"
>+                              "member='%s'",
>+                              priv->path, priv->interface, signal_name);
>+    }
> }
> 
> static char *
>@@ -977,16 +1004,12 @@ dbus_g_proxy_manager_register (DBusGProxyManager *manager,
>        * but only if the server is a message bus,
>        * not if it's a peer.
>        */
>-      char *rule;
>       guint *refcount;
> 
>-      rule = g_proxy_get_signal_match_rule (proxy);
>-      /* We don't check for errors; it's not like anyone would handle them, and
>-       * we don't want a round trip here.
>-       */
>-      dbus_bus_add_match (manager->connection, rule, NULL);
>-      g_free (rule);
>-       
>+      g_assert (list->signal_subscriptions == NULL);
>+      list->signal_subscriptions = g_hash_table_new_full (g_str_hash,
>+          g_str_equal, g_free, (GDestroyNotify)g_hash_table_destroy);
>+
>       refcount = g_hash_table_lookup (manager->owner_match_rules, priv->name);
> 
>       if (refcount != NULL)
>@@ -1105,17 +1128,33 @@ dbus_g_proxy_manager_unregister (DBusGProxyManager *manager,
> 	}
>     }
> 
>+  if (list->signal_subscriptions != NULL)
>+    {
>+      GHashTableIter iter;
>+      gpointer proxy_set;
>+      gpointer signal_name;
>+
>+      g_hash_table_iter_init (&iter, list->signal_subscriptions);
>+      while (g_hash_table_iter_next (&iter, &signal_name, &proxy_set))
>+        {
>+          g_hash_table_remove (proxy_set, proxy);
>+          if (g_hash_table_size (proxy_set) == 0)
>+            {
>+              char *rule;
>+
>+              rule = g_proxy_get_signal_match_rule (proxy, (gchar *) signal_name);
>+              dbus_bus_remove_match (priv->manager->connection,
>+                  rule, NULL);
>+              g_free (rule);
>+            }
>+        }
>+    }
>+
>   if (list->proxies == NULL)
>     {
>-      char *rule;
>       g_hash_table_remove (manager->proxy_lists,
>                            tri);
> 
>-      rule = g_proxy_get_signal_match_rule (proxy);
>-      dbus_bus_remove_match (manager->connection,
>-                             rule, NULL);
>-      g_free (rule);
>-
>       if (priv->name)
>         {
>           guint *refcount;
>@@ -1124,7 +1163,8 @@ dbus_g_proxy_manager_unregister (DBusGProxyManager *manager,
> 
>           if (*refcount == 0)
>             {
>-              rule = get_owner_match_rule (priv->name);
>+              gchar *rule = get_owner_match_rule (priv->name);
>+
>               dbus_bus_remove_match (manager->connection,
>                                      rule, NULL);
>               g_free (rule);
>@@ -3082,13 +3122,70 @@ dbus_g_proxy_connect_signal (DBusGProxy             *proxy,
>   GClosure *closure;
>   GQuark q;
>   DBusGProxyPrivate *priv;
>+  char *tri;
>+  DBusGProxyList *list;
> 
>   g_return_if_fail (DBUS_IS_G_PROXY (proxy));
>   g_return_if_fail (!DBUS_G_PROXY_DESTROYED (proxy));
>   g_return_if_fail (g_dbus_is_member_name (signal_name));
>   g_return_if_fail (handler != NULL);
>-  
>+
>   priv = DBUS_G_PROXY_GET_PRIVATE(proxy);
>+
>+  tri = tristring_from_proxy (proxy);
>+  list = g_hash_table_lookup (priv->manager->proxy_lists, tri);
>+  g_free (tri);
>+  /* We have to add match rules to the server,
>+   * but only if the server is a message bus,
>+   * not if it's a peer.
>+   */
>+  if (priv->name)
>+    {
>+      gchar *orig_key;
>+      GHashTable *proxy_set;
>+      gboolean found;
>+      gint handler_count;
>+      gpointer value;
>+
>+      g_assert (list->signal_subscriptions != NULL);
>+      found = g_hash_table_lookup_extended
>+        (list->signal_subscriptions, signal_name, (gpointer *) &orig_key,
>+         (gpointer *) &proxy_set);
>+
>+      if (!found || g_hash_table_size (proxy_set) == 0)
>+        {
>+          char *rule;
>+
>+          rule = g_proxy_get_signal_match_rule (proxy, signal_name);
>+          /* We don't check for errors; it's not like anyone would handle
>+           * them, and we don't want a round trip here.
>+           */
>+          dbus_bus_add_match (priv->manager->connection,
>+                              rule, NULL);
>+          g_free (rule);
>+        }
>+
>+      if (!found)
>+        {
>+          proxy_set = g_hash_table_new (NULL, NULL);
>+          orig_key = g_strdup (signal_name);
>+        }
>+
>+      if (g_hash_table_lookup_extended (proxy_set, proxy, NULL,
>+            &value))
>+        {
>+          handler_count = GPOINTER_TO_UINT (value) + 1;
>+        }
>+      else
>+        {
>+          handler_count = 1;
>+        }
>+      g_hash_table_insert (proxy_set, proxy, GINT_TO_POINTER (handler_count));
>+
>+      g_hash_table_steal (list->signal_subscriptions, signal_name);
>+      g_hash_table_insert (list->signal_subscriptions, orig_key, proxy_set);
>+    }
>+
>   name = create_signal_name (priv->interface, signal_name);
> 
>   q = g_quark_try_string (name);
>@@ -3131,10 +3228,15 @@ dbus_g_proxy_disconnect_signal (DBusGProxy             *proxy,
>                                 GCallback               handler,
>                                 void                   *data)
> {
>+  guint matched_count;
>+  gint handler_count;
>   char *name;
>   GQuark q;
>   DBusGProxyPrivate *priv;
>-  
>+  char *tri;
>+  DBusGProxyList *list;
>+  gchar *_signal_name;
>+
>   g_return_if_fail (DBUS_IS_G_PROXY (proxy));
>   g_return_if_fail (!DBUS_G_PROXY_DESTROYED (proxy));
>   g_return_if_fail (g_dbus_is_member_name (signal_name));
>@@ -3144,25 +3246,72 @@ dbus_g_proxy_disconnect_signal (DBusGProxy             *proxy,
>   name = create_signal_name (priv->interface, signal_name);
> 
>   q = g_quark_try_string (name);
>-  
>-  if (q != 0)
>-    {
>-      g_signal_handlers_disconnect_matched (G_OBJECT (proxy),
>-                                            G_SIGNAL_MATCH_DETAIL |
>-                                            G_SIGNAL_MATCH_FUNC   |
>-                                            G_SIGNAL_MATCH_DATA,
>-                                            signals[RECEIVED],
>-                                            q,
>-                                            NULL,
>-                                            G_CALLBACK (handler), data);
>-    }
>-  else
>+  g_free (name);
>+
>+  if (q == 0)
>     {
>       g_warning ("Attempt to disconnect from signal '%s' which is not registered\n",
>-                 name);
>+                 signal_name);
>+      return;
>     }
> 
>-  g_free (name);
>+  /* signal_name may be freed by g_signal_handlers_disconnect_matched() :'(
>+   * Keep a copy while we need it
>+   */
>+  _signal_name = g_strdup (signal_name);
>+  matched_count = g_signal_handlers_disconnect_matched (G_OBJECT (proxy),
>+      G_SIGNAL_MATCH_DETAIL | G_SIGNAL_MATCH_FUNC | G_SIGNAL_MATCH_DATA,
>+      signals[RECEIVED], q, NULL, G_CALLBACK (handler), data);
>+
>+  tri = tristring_from_proxy (proxy);
>+  list = g_hash_table_lookup (priv->manager->proxy_lists, tri);
>+  g_free (tri);
>+
>+  /* Remove a match rule */
>+  if (list->signal_subscriptions != NULL)
>+    {
>+      GHashTable *proxy_set = g_hash_table_lookup (list->signal_subscriptions,
>+          _signal_name);
>+      gpointer value;
>+
>+      if (proxy_set == NULL || !g_hash_table_lookup_extended (proxy_set, proxy,
>+            NULL, &value))
>+        {
>+          g_warning ("Attempt to disconnect from signal '%s' which is not"
>+              " registered\n", _signal_name);
>+          g_free (_signal_name);
>+          return;
>+        }
>+
>+      handler_count = GPOINTER_TO_INT (value);
>+      handler_count -= matched_count;
>+      g_assert (handler_count >= 0);
>+      if (handler_count == 0)
>+        {
>+          g_hash_table_remove (proxy_set, proxy);
>+        }
>+      else
>+        {
>+          g_hash_table_insert (proxy_set, proxy,
>+              GINT_TO_POINTER (handler_count));
>+        }
>+
>+      if (g_hash_table_size (proxy_set) == 0)
>+        {
>+          char *rule;
>+
>+          rule = g_proxy_get_signal_match_rule (proxy, _signal_name);
>+          /* We don't check for errors; it's not like anyone would handle them,
>+           * and we don't want a round trip here.
>+           */
>+          dbus_bus_remove_match (priv->manager->connection,
>+              rule, NULL);
>+          g_free (rule);
>+
>+          g_hash_table_remove (list->signal_subscriptions, _signal_name);
>+        }
>+    }
>+  g_free (_signal_name);
> }
> 
> /**
>-- 
>1.7.6.3
>

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