2002-12-24 Havoc Pennington <hp@pobox.com>

	* glib/dbus-gthread.c: fix include

	* glib/dbus-glib.h: rename DBusMessageHandler for now.
	I think glib API needs to change, though, as you don't
	want to use DBusMessageFunction, you want to use the
	DBusMessageHandler object. Probably
	dbus_connection_open_with_g_main_loop()
	and dbus_connection_setup_g_main_loop() or something like that
	(but think of better names...) that just create a connection
	that has watch/timeout functions etc. already set up.

	* dbus/dbus-connection.c
	(dbus_connection_send_message_with_reply): new function just to
	show how the message handler helps us deal with replies.

	* dbus/dbus-list.c (_dbus_list_remove_last): new function

	* dbus/dbus-string.c (_dbus_string_test): free a string that
	wasn't

	* dbus/dbus-hash.c: use memory pools for the hash entries
	(rebuild_table): be more paranoid about overflow, and
	shrink table when we can
	(_dbus_hash_test): reduce number of sprintfs and write
	valid C89. Add tests for case where we grow and then
	shrink the hash table.

	* dbus/dbus-mempool.h, dbus/dbus-mempool.c: memory pools

	* dbus/dbus-connection.c (dbus_connection_register_handler)
	(dbus_connection_unregister_handler): new functions

	* dbus/dbus-message.c (dbus_message_get_name): new

	* dbus/dbus-list.c: fix docs typo

	* dbus/dbus-message-handler.h, dbus/dbus-message-handler.c:
	an object representing a handler for messages.

17 files changed, 1541 insertions, 67 deletions

diff --git a/dbus/Makefile.am b/dbus/Makefile.am
index b5071f0b..74b5dfbb 100644
--- a/dbus/Makefile.am
+++ b/dbus/Makefile.am
@@ -11,6 +11,7 @@ dbusinclude_HEADERS=				\
 	dbus-macros.h				\
 	dbus-memory.h				\
 	dbus-message.h				\
+	dbus-message-handler.h			\
 	dbus-server.h				\
 	dbus-threads.h				\
 	dbus-types.h
@@ -21,6 +22,7 @@ libdbus_1_la_SOURCES=				\
 	dbus-errors.c				\
 	dbus-memory.c				\
 	dbus-message.c				\
+	dbus-message-handler.c			\
 	dbus-message-internal.h			\
 	dbus-server.c				\
 	dbus-server-protected.h			\
@@ -51,6 +53,8 @@ libdbus_convenience_la_SOURCES=			\
 	dbus-internals.h			\
 	dbus-list.c				\
 	dbus-list.h				\
+	dbus-mempool.c				\
+	dbus-mempool.h				\
 	dbus-string.c				\
 	dbus-string.h				\
 	dbus-sysdeps.c				\
diff --git a/dbus/dbus-connection-internal.h b/dbus/dbus-connection-internal.h
index 7260bde0..cf932ddd 100644
--- a/dbus/dbus-connection-internal.h
+++ b/dbus/dbus-connection-internal.h
@@ -59,6 +59,20 @@ void            _dbus_connection_do_iteration           (DBusConnection *connect
 void            _dbus_connection_transport_error        (DBusConnection *connection,
                                                          DBusResultCode  result_code);
 
+void            _dbus_connection_handler_destroyed      (DBusConnection *connection,
+                                                         DBusMessageHandler *handler);
+
+
+dbus_bool_t       _dbus_message_handler_add_connection    (DBusMessageHandler *handler,
+                                                           DBusConnection     *connection);
+void              _dbus_message_handler_remove_connection (DBusMessageHandler *handler,
+                                                           DBusConnection     *connection);
+DBusHandlerResult _dbus_message_handler_handle_message    (DBusMessageHandler *handler,
+                                                           DBusConnection     *connection,
+                                                           DBusMessage        *message);
+
+
+
 DBUS_END_DECLS;
 
 #endif /* DBUS_CONNECTION_INTERNAL_H */
diff --git a/dbus/dbus-connection.c b/dbus/dbus-connection.c
index 3c6df57f..4a40f0b0 100644
--- a/dbus/dbus-connection.c
+++ b/dbus/dbus-connection.c
@@ -27,6 +27,7 @@
 #include "dbus-watch.h"
 #include "dbus-connection-internal.h"
 #include "dbus-list.h"
+#include "dbus-hash.h"
 #include "dbus-message-internal.h"
 
 /**
@@ -75,6 +76,10 @@ struct DBusConnection
   DBusConnectionErrorFunction error_function; /**< Callback for errors. */
   void *error_data;                           /**< Data for error callback. */
   DBusFreeFunction error_free_data_function;  /**< Free function for error callback data. */
+  DBusHashTable *handler_table; /**< Table of registered DBusMessageHandler */
+  DBusList *filter_list;        /**< List of filters. */
+  int filters_serial;           /**< Increments when the list of filters is changed. */
+  int handlers_serial;          /**< Increments when the handler table is changed. */
 };
 
 /**
@@ -270,13 +275,21 @@ _dbus_connection_new_for_transport (DBusTransport *transport)
 {
   DBusConnection *connection;
   DBusWatchList *watch_list;
+  DBusHashTable *handler_table;
   
   watch_list = NULL;
   connection = NULL;
+  handler_table = NULL;
   
   watch_list = _dbus_watch_list_new ();
   if (watch_list == NULL)
     goto error;
+
+  handler_table =
+    _dbus_hash_table_new (DBUS_HASH_STRING,
+                          dbus_free, NULL);
+  if (handler_table == NULL)
+    goto error;
   
   connection = dbus_new0 (DBusConnection, 1);
   if (connection == NULL)
@@ -285,7 +298,9 @@ _dbus_connection_new_for_transport (DBusTransport *transport)
   connection->refcount = 1;
   connection->transport = transport;
   connection->watches = watch_list;
-
+  connection->handler_table = handler_table;
+  connection->filter_list = NULL;
+  
   _dbus_transport_ref (transport);
   _dbus_transport_set_connection (transport, connection);
   
@@ -293,14 +308,56 @@ _dbus_connection_new_for_transport (DBusTransport *transport)
   
  error:
 
-  _dbus_assert (connection == NULL);  
+  if (connection != NULL)
+    dbus_free (connection);
 
+  if (handler_table)
+    _dbus_hash_table_unref (handler_table);
+  
   if (watch_list)
     _dbus_watch_list_free (watch_list);
   
   return NULL;
 }
 
+/**
+ * Used to notify a connection when a DBusMessageHandler is
+ * destroyed, so the connection can drop any reference
+ * to the handler.
+ *
+ * @param connection the connection
+ * @param handler the handler
+ */
+void
+_dbus_connection_handler_destroyed (DBusConnection     *connection,
+                                    DBusMessageHandler *handler)
+{
+  DBusHashIter iter;
+  DBusList *link;
+
+  _dbus_hash_iter_init (connection->handler_table, &iter);
+  while (_dbus_hash_iter_next (&iter))
+    {
+      DBusMessageHandler *h = _dbus_hash_iter_get_value (&iter);
+
+      if (h == handler)
+        _dbus_hash_iter_remove_entry (&iter);
+    }
+
+  link = _dbus_list_get_first_link (&connection->filter_list);
+  while (link != NULL)
+    {
+      DBusMessageHandler *h = link->data;
+      DBusList *next = _dbus_list_get_next_link (&connection->filter_list, link);
+
+      if (h == handler)
+        _dbus_list_remove_link (&connection->filter_list,
+                                link);
+      
+      link = next;
+    }
+}
+
 /** @} */
 
 /**
@@ -377,11 +434,38 @@ dbus_connection_unref (DBusConnection *connection)
   connection->refcount -= 1;
   if (connection->refcount == 0)
     {
+      DBusHashIter iter;
+      DBusList *link;
+
       /* free error data as a side effect */
       dbus_connection_set_error_function (connection,
                                           NULL, NULL, NULL);
 
       _dbus_watch_list_free (connection->watches);
+
+      _dbus_hash_iter_init (connection->handler_table, &iter);
+      while (_dbus_hash_iter_next (&iter))
+        {
+          DBusMessageHandler *h = _dbus_hash_iter_get_value (&iter);
+          
+          _dbus_message_handler_remove_connection (h, connection);
+        }
+
+      link = _dbus_list_get_first_link (&connection->filter_list);
+      while (link != NULL)
+        {
+          DBusMessageHandler *h = link->data;
+          DBusList *next = _dbus_list_get_next_link (&connection->filter_list, link);
+          
+          _dbus_message_handler_remove_connection (h, connection);
+          
+          link = next;
+        }
+      
+      _dbus_hash_table_unref (connection->handler_table);
+      connection->handler_table = NULL;
+
+      _dbus_list_clear (&connection->filter_list);
       
       _dbus_list_foreach (&connection->outgoing_messages,
                           (DBusForeachFunction) dbus_message_unref,
@@ -471,6 +555,66 @@ dbus_connection_send_message (DBusConnection *connection,
 }
 
 /**
+ * Queues a message to send, as with dbus_connection_send_message(),
+ * but also sets up a DBusMessageHandler to receive a reply to the
+ * message. If no reply is received in the given timeout_milliseconds,
+ * expires the pending reply and sends the DBusMessageHandler a
+ * synthetic error reply (generated in-process, not by the remote
+ * application) indicating that a timeout occurred.
+ *
+ * Reply handlers see their replies after message filters see them,
+ * but before message handlers added with
+ * dbus_connection_register_handler() see them, regardless of the
+ * reply message's name. Reply handlers are only handed a single
+ * message as a reply, after a reply has been seen the handler is
+ * removed. If a filter filters out the reply before the handler sees
+ * it, the handler is not removed but the timeout will immediately
+ * fire again. If a filter was dumb and kept removing the timeout
+ * reply then we'd get in an infinite loop.
+ * 
+ * If #NULL is passed for the reply_handler, the timeout reply will
+ * still be generated and placed into the message queue, but no
+ * specific message handler will receive the reply.
+ *
+ * If -1 is passed for the timeout, a sane default timeout is used. -1
+ * is typically the best value for the timeout for this reason, unless
+ * you want a very short or very long timeout.  There is no way to
+ * avoid a timeout entirely, other than passing INT_MAX for the
+ * timeout to postpone it indefinitely.
+ * 
+ * @param connection the connection
+ * @param message the message to send
+ * @param reply_handler message handler expecting the reply, or #NULL
+ * @param timeout_milliseconds timeout in milliseconds or -1 for default
+ * @param result return location for result code
+ * @returns #TRUE if the message is successfully queued, #FALSE if no memory.
+ *
+ * @todo this function isn't implemented because we need message serials
+ * and other slightly more rich DBusMessage implementation in order to
+ * implement it. The basic idea will be to keep a hash of serials we're
+ * expecting a reply to, and also to add a way to tell GLib or Qt to
+ * install a timeout. Then install a timeout which is the shortest
+ * timeout of any pending reply.
+ *
+ * @todo implement non-reentrant "block for reply" variant.  i.e. send
+ * a message, block until we get a reply, then pull reply out of
+ * message queue and return it, *without dispatching any handlers for
+ * any other messages* - used for non-reentrant "method calls" We can
+ * block properly for this using _dbus_connection_do_iteration().
+ * 
+ */
+dbus_bool_t
+dbus_connection_send_message_with_reply (DBusConnection     *connection,
+                                         DBusMessage        *message,
+                                         DBusMessageHandler *reply_handler,
+                                         int                 timeout_milliseconds,
+                                         DBusResultCode     *result)
+{
+  /* FIXME */
+  return dbus_connection_send_message (connection, message, result);
+}
+
+/**
  * Blocks until the outgoing message queue is empty.
  *
  * @param connection the connection.
@@ -532,6 +676,90 @@ dbus_connection_pop_message (DBusConnection *connection)
 }
 
 /**
+ * Pops the first-received message from the current incoming message
+ * queue, runs any handlers for it, then unrefs the message.
+ *
+ * @param connection the connection
+ * @returns #TRUE if the queue is not empty after dispatch
+ *
+ * @todo this function is not properly robust against reentrancy,
+ * that is, if handlers are added/removed while dispatching
+ * a message, things will get messed up.
+ */
+dbus_bool_t
+dbus_connection_dispatch_message (DBusConnection *connection)
+{
+  DBusMessage *message;
+  int filter_serial;
+  int handler_serial;
+  DBusList *link;
+  DBusHandlerResult result;
+  const char *name;
+  
+  dbus_connection_ref (connection);
+  
+  message = dbus_connection_pop_message (connection);
+  if (message == NULL)
+    return FALSE;
+
+  filter_serial = connection->filters_serial;
+  handler_serial = connection->handlers_serial;
+
+  result = DBUS_HANDLER_RESULT_ALLOW_MORE_HANDLERS;
+  
+  link = _dbus_list_get_first_link (&connection->filter_list);
+  while (link != NULL)
+    {
+      DBusMessageHandler *handler = link->data;
+      DBusList *next = _dbus_list_get_next_link (&connection->filter_list, link);
+      
+      result = _dbus_message_handler_handle_message (handler, connection,
+                                                     message);
+
+      if (result == DBUS_HANDLER_RESULT_REMOVE_MESSAGE)
+        goto out;
+
+      if (filter_serial != connection->filters_serial)
+        {
+          _dbus_warn ("Message filters added or removed while dispatching filters - not currently supported!\n");
+          goto out;
+        }
+      
+      link = next;
+    }
+
+  name = dbus_message_get_name (message);
+  if (name != NULL)
+    {
+      DBusMessageHandler *handler;
+      
+      handler = _dbus_hash_table_lookup_string (connection->handler_table,
+                                                name);
+      if (handler != NULL)
+        {
+
+          result = _dbus_message_handler_handle_message (handler, connection,
+                                                         message);
+      
+          if (result == DBUS_HANDLER_RESULT_REMOVE_MESSAGE)
+            goto out;
+          
+          if (handler_serial != connection->handlers_serial)
+            {
+              _dbus_warn ("Message handlers added or removed while dispatching handlers - not currently supported!\n");
+              goto out;
+            }
+        }
+    }
+
+ out:
+  dbus_connection_unref (connection);
+  dbus_message_unref (message);
+  
+  return connection->n_incoming > 0;
+}
+
+/**
  * Sets the error handler function for the connection.
  * 
  * @param connection the connection.
@@ -623,4 +851,185 @@ dbus_connection_handle_watch (DBusConnection              *connection,
                                 watch, condition);
 }
 
+/**
+ * Adds a message filter. Filters are handlers that are run on
+ * all incoming messages, prior to the normal handlers
+ * registered with dbus_connection_register_handler().
+ * Filters are run in the order that they were added.
+ * The same handler can be added as a filter more than once, in
+ * which case it will be run more than once.
+ *
+ * @param connection the connection
+ * @param handler the handler
+ * @returns #TRUE on success, #FALSE if not enough memory.
+ */
+dbus_bool_t
+dbus_connection_add_filter (DBusConnection      *connection,
+                            DBusMessageHandler  *handler)
+{
+  if (!_dbus_message_handler_add_connection (handler, connection))
+    return FALSE;
+
+  if (!_dbus_list_append (&connection->filter_list,
+                          handler))
+    {
+      _dbus_message_handler_remove_connection (handler, connection);
+      return FALSE;
+    }
+
+  connection->filters_serial += 1;
+  
+  return TRUE;
+}
+
+/**
+ * Removes a previously-added message filter. It is a programming
+ * error to call this function for a handler that has not
+ * been added as a filter. If the given handler was added
+ * more than once, only one instance of it will be removed
+ * (the most recently-added instance).
+ *
+ * @param connection the connection
+ * @param handler the handler to remove
+ *
+ */
+void
+dbus_connection_remove_filter (DBusConnection      *connection,
+                               DBusMessageHandler  *handler)
+{
+  if (!_dbus_list_remove_last (&connection->filter_list, handler))
+    {
+      _dbus_warn ("Tried to remove a DBusConnection filter that had not been added\n");
+      return;
+    }
+
+  _dbus_message_handler_remove_connection (handler, connection);
+
+  connection->filters_serial += 1;
+}
+
+/**
+ * Registers a handler for a list of message names. A single handler
+ * can be registered for any number of message names, but each message
+ * name can only have one handler at a time. It's not allowed to call
+ * this function with the name of a message that already has a
+ * handler. If the function returns #FALSE, the handlers were not
+ * registered due to lack of memory.
+ * 
+ * @param connection the connection
+ * @param handler the handler
+ * @param messages_to_handle the messages to handle
+ * @param n_messages the number of message names in messages_to_handle
+ * @returns #TRUE on success, #FALSE if no memory or another handler already exists
+ * 
+ **/
+dbus_bool_t
+dbus_connection_register_handler (DBusConnection     *connection,
+                                  DBusMessageHandler *handler,
+                                  const char        **messages_to_handle,
+                                  int                 n_messages)
+{
+  int i;
+
+  i = 0;
+  while (i < n_messages)
+    {
+      DBusHashIter iter;
+      char *key;
+
+      key = _dbus_strdup (messages_to_handle[i]);
+      if (key == NULL)
+        goto failed;
+      
+      if (!_dbus_hash_iter_lookup (connection->handler_table,
+                                   key, TRUE,
+                                   &iter))
+        {
+          dbus_free (key);
+          goto failed;
+        }
+
+      if (_dbus_hash_iter_get_value (&iter) != NULL)
+        {
+          _dbus_warn ("Bug in application: attempted to register a second handler for %s\n",
+                      messages_to_handle[i]);
+          dbus_free (key); /* won't have replaced the old key with the new one */
+          goto failed;
+        }
+
+      if (!_dbus_message_handler_add_connection (handler, connection))
+        {
+          _dbus_hash_iter_remove_entry (&iter);
+          /* key has freed on nuking the entry */
+          goto failed;
+        }
+      
+      _dbus_hash_iter_set_value (&iter, handler);
+
+      connection->handlers_serial += 1;
+      
+      ++i;
+    }
+  
+  return TRUE;
+  
+ failed:
+  /* unregister everything registered so far,
+   * so we don't fail partially
+   */
+  dbus_connection_unregister_handler (connection,
+                                      handler,
+                                      messages_to_handle,
+                                      i);
+
+  return FALSE;
+}
+
+/**
+ * Unregisters a handler for a list of message names. The handlers
+ * must have been previously registered.
+ *
+ * @param connection the connection
+ * @param handler the handler
+ * @param messages_to_handle the messages to handle
+ * @param n_messages the number of message names in messages_to_handle
+ * 
+ **/
+void
+dbus_connection_unregister_handler (DBusConnection     *connection,
+                                    DBusMessageHandler *handler,
+                                    const char        **messages_to_handle,
+                                    int                 n_messages)
+{
+  int i;
+
+  i = 0;
+  while (i < n_messages)
+    {
+      DBusHashIter iter;
+
+      if (!_dbus_hash_iter_lookup (connection->handler_table,
+                                   (char*) messages_to_handle[i], FALSE,
+                                   &iter))
+        {
+          _dbus_warn ("Bug in application: attempted to unregister handler for %s which was not registered\n",
+                      messages_to_handle[i]);
+        }
+      else if (_dbus_hash_iter_get_value (&iter) != handler)
+        {
+          _dbus_warn ("Bug in application: attempted to unregister handler for %s which was registered by a different handler\n",
+                      messages_to_handle[i]);
+        }
+      else
+        {
+          _dbus_hash_iter_remove_entry (&iter);
+          _dbus_message_handler_remove_connection (handler, connection);
+        }
+
+      ++i;
+    }
+
+  connection->handlers_serial += 1;
+}
+
 /** @} */
diff --git a/dbus/dbus-connection.h b/dbus/dbus-connection.h
index ceb5728f..518295b2 100644
--- a/dbus/dbus-connection.h
+++ b/dbus/dbus-connection.h
@@ -35,6 +35,13 @@ DBUS_BEGIN_DECLS;
 
 typedef struct DBusConnection DBusConnection;
 typedef struct DBusWatch DBusWatch;
+typedef struct DBusMessageHandler DBusMessageHandler;
+
+typedef enum
+{
+  DBUS_HANDLER_RESULT_REMOVE_MESSAGE,     /**< Remove this message, no further processing. */
+  DBUS_HANDLER_RESULT_ALLOW_MORE_HANDLERS /**< Run any additional handlers that are interested on this message. */
+} DBusHandlerResult;
 
 typedef enum
 {
@@ -63,15 +70,21 @@ void            dbus_connection_ref              (DBusConnection *connection);
 void            dbus_connection_unref            (DBusConnection *connection);
 void            dbus_connection_disconnect       (DBusConnection *connection);
 dbus_bool_t     dbus_connection_get_is_connected (DBusConnection *connection);
-dbus_bool_t     dbus_connection_send_message     (DBusConnection *connection,
-                                                  DBusMessage    *message,
-                                                  DBusResultCode *result);
 void            dbus_connection_flush            (DBusConnection *connection);
 
 int          dbus_connection_get_n_messages      (DBusConnection *connection);
 DBusMessage* dbus_connection_peek_message        (DBusConnection *connection);
 DBusMessage* dbus_connection_pop_message         (DBusConnection *connection);
+dbus_bool_t  dbus_connection_dispatch_message    (DBusConnection *connection);
 
+dbus_bool_t dbus_connection_send_message            (DBusConnection     *connection,
+                                                     DBusMessage        *message,
+                                                     DBusResultCode     *result);
+dbus_bool_t dbus_connection_send_message_with_reply (DBusConnection     *connection,
+                                                     DBusMessage        *message,
+                                                     DBusMessageHandler *reply_handler,
+                                                     int                 timeout_milliseconds,
+                                                     DBusResultCode     *result);
 
 void dbus_connection_set_error_function  (DBusConnection              *connection,
                                           DBusConnectionErrorFunction  error_function,
@@ -86,7 +99,6 @@ void dbus_connection_handle_watch        (DBusConnection              *connectio
                                           DBusWatch                   *watch,
                                           unsigned int                 condition);
 
-
 int          dbus_watch_get_fd    (DBusWatch        *watch);
 unsigned int dbus_watch_get_flags (DBusWatch        *watch);
 void*        dbus_watch_get_data  (DBusWatch        *watch);
@@ -95,6 +107,21 @@ void         dbus_watch_set_data  (DBusWatch        *watch,
                                    DBusFreeFunction  free_data_function);
 
 
+/* Handlers */
+dbus_bool_t dbus_connection_add_filter         (DBusConnection      *connection,
+                                                DBusMessageHandler  *handler);
+void        dbus_connection_remove_filter      (DBusConnection      *connection,
+                                                DBusMessageHandler  *handler);
+
+dbus_bool_t dbus_connection_register_handler   (DBusConnection      *connection,
+                                                DBusMessageHandler  *handler,
+                                                const char         **messages_to_handle,
+                                                int                  n_messages);
+void        dbus_connection_unregister_handler (DBusConnection      *connection,
+                                                DBusMessageHandler  *handler,
+                                                const char         **messages_to_handle,
+                                                int                  n_messages);
+
 DBUS_END_DECLS;
 
 #endif /* DBUS_CONNECTION_H */
diff --git a/dbus/dbus-hash.c b/dbus/dbus-hash.c
index f4a22586..9cec1c1d 100644
--- a/dbus/dbus-hash.c
+++ b/dbus/dbus-hash.c
@@ -76,6 +76,7 @@
 
 #include "dbus-hash.h"
 #include "dbus-internals.h"
+#include "dbus-mempool.h"
 
 /**
  * @defgroup DBusHashTable Hash table
@@ -92,13 +93,6 @@
  *
  * The guts of DBusHashTable.
  *
- * @todo rebuild_table() should be modified to also shrink the hash bucket
- * array when appropriate; otherwise if a hash table has been
- * very large but is now small, iteration becomes inefficient.
- * We should still only shrink when adding hash entries though, not
- * when removing them, so that you can still iterate over the hash
- * removing entries. So if you added 5000, removed 4000, the
- * shrinking would happen next time an entry was added.
  * @{
  */
 
@@ -114,6 +108,15 @@
  * preliminary values that are arbitrarily similar will end up in
  * different buckets.  The hash function was taken from a
  * random-number generator. (This is used to hash integers.)
+ *
+ * The down_shift drops off the high bits of the hash index, and
+ * decreases as we increase the number of hash buckets (to keep more
+ * range in the hash index). The mask also strips high bits and strips
+ * fewer high bits as the number of hash buckets increases.
+ * I don't understand two things: why is the initial downshift 28
+ * to keep 4 bits when the initial mask is 011 to keep 2 bits,
+ * and why do we have both a mask and a downshift?
+ * 
  */
 #define RANDOM_INDEX(table, i) \
     (((((long) (i))*1103515245) >> (table)->down_shift) & (table)->mask)
@@ -121,6 +124,7 @@
 /**
  * Initial number of buckets in hash table (hash table statically
  * allocates its buckets for this size and below).
+ * The initial mask has to be synced to this.
  */
 #define DBUS_SMALL_HASH_TABLE 4
 
@@ -176,9 +180,12 @@ struct DBusHashTable {
   int n_entries;                       /**< Total number of entries present
                                         * in table.
                                         */
-  int rebuild_size;                    /**< Enlarge table when numEntries gets
+  int hi_rebuild_size;                 /**< Enlarge table when n_entries gets
                                         * to be this large.
                                         */
+  int lo_rebuild_size;                 /**< Shrink table when n_entries gets
+                                        * below this.
+                                        */
   int down_shift;                      /**< Shift count used in hashing
                                         * function.  Designed to use high-
                                         * order bits of randomized keys.
@@ -193,6 +200,8 @@ struct DBusHashTable {
 
   DBusFreeFunction free_key_function;   /**< Function to free keys */
   DBusFreeFunction free_value_function; /**< Function to free values */
+
+  DBusMemPool *entry_pool;              /**< Memory pool for hash entries */
 };
 
 /** 
@@ -269,22 +278,34 @@ _dbus_hash_table_new (DBusHashType     type,
                       DBusFreeFunction value_free_function)
 {
   DBusHashTable *table;
-
+  DBusMemPool *entry_pool;
+  
   table = dbus_new0 (DBusHashTable, 1);
   if (table == NULL)
     return NULL;
+
+  entry_pool = _dbus_mem_pool_new (sizeof (DBusHashEntry), TRUE);
+  if (entry_pool == NULL)
+    {
+      dbus_free (table);
+      return NULL;
+    }
   
   table->refcount = 1;
-
+  table->entry_pool = entry_pool;
+  
   _dbus_assert (DBUS_SMALL_HASH_TABLE == _DBUS_N_ELEMENTS (table->static_buckets));
   
   table->buckets = table->static_buckets;  
   table->n_buckets = DBUS_SMALL_HASH_TABLE;
   table->n_entries = 0;
-  table->rebuild_size = DBUS_SMALL_HASH_TABLE * REBUILD_MULTIPLIER;
+  table->hi_rebuild_size = DBUS_SMALL_HASH_TABLE * REBUILD_MULTIPLIER;
+  table->lo_rebuild_size = 0;
   table->down_shift = 28;
   table->mask = 3;
   table->key_type = type;
+
+  _dbus_assert (table->mask < table->n_buckets);
   
   switch (table->key_type)
     {
@@ -330,12 +351,12 @@ _dbus_hash_table_unref (DBusHashTable *table)
 
   if (table->refcount == 0)
     {
+#if 0
       DBusHashEntry *entry;
       DBusHashEntry *next;
       int i;
 
       /* Free the entries in the table. */
-      
       for (i = 0; i < table->n_buckets; i++)
         {
           entry = table->buckets[i];
@@ -348,7 +369,11 @@ _dbus_hash_table_unref (DBusHashTable *table)
               entry = next;
             }
         }
-
+#else
+      /* We can do this very quickly with memory pools ;-) */
+      _dbus_mem_pool_free (table->entry_pool);
+#endif
+      
       /* Free the bucket array, if it was dynamically allocated. */
       if (table->buckets != table->static_buckets)
         dbus_free (table->buckets);
@@ -362,8 +387,8 @@ alloc_entry (DBusHashTable *table)
 {
   DBusHashEntry *entry;
 
-  entry = dbus_new0 (DBusHashEntry, 1);
-
+  entry = _dbus_mem_pool_alloc (table->entry_pool);
+  
   return entry;
 }
 
@@ -376,7 +401,7 @@ free_entry (DBusHashTable  *table,
   if (table->free_value_function)
     (* table->free_value_function) (entry->value);
               
-  dbus_free (entry);
+  _dbus_mem_pool_dealloc (table->entry_pool, entry);
 }
 
 static void
@@ -631,6 +656,9 @@ _dbus_hash_iter_get_string_key (DBusHashIter *iter)
  * because create_if_not_found was #FALSE and the entry
  * did not exist.
  *
+ * If create_if_not_found is #TRUE and the entry is created, the hash
+ * table takes ownership of the key that's passed in.
+ *
  * For a hash table of type #DBUS_HASH_INT, cast the int
  * key to the key parameter using #_DBUS_INT_TO_POINTER().
  * 
@@ -698,8 +726,12 @@ add_entry (DBusHashTable   *table,
     *bucket = b;
   
   table->n_entries += 1;
-  
-  if (table->n_entries >= table->rebuild_size)
+
+  /* note we ONLY rebuild when ADDING - because you can iterate over a
+   * table and remove entries safely.
+   */
+  if (table->n_entries >= table->hi_rebuild_size ||
+      table->n_entries < table->lo_rebuild_size)
     rebuild_table (table);
 
   return entry;
@@ -814,34 +846,82 @@ static void
 rebuild_table (DBusHashTable *table)
 {
   int old_size;
+  int new_buckets;
   DBusHashEntry **old_buckets;
   DBusHashEntry **old_chain;
   DBusHashEntry *entry;
-
+  dbus_bool_t growing;
+  
   /*
    * Allocate and initialize the new bucket array, and set up
    * hashing constants for new array size.
    */
+
+  growing = table->n_entries >= table->hi_rebuild_size;
   
   old_size = table->n_buckets;
   old_buckets = table->buckets;
 
-  table->n_buckets *= 4;
-  table->buckets = dbus_new0 (DBusHashEntry*, table->n_buckets);  
+  if (growing)
+    {
+      /* overflow paranoia */
+      if (table->n_buckets < _DBUS_INT_MAX / 4 &&
+          table->down_shift >= 0)
+        new_buckets = table->n_buckets * 4;
+      else
+        return; /* can't grow anymore */
+    }
+  else
+    {
+      new_buckets = table->n_buckets / 4;
+      if (new_buckets < DBUS_SMALL_HASH_TABLE)
+        return; /* don't bother shrinking this far */
+    }
+
+  table->buckets = dbus_new0 (DBusHashEntry*, new_buckets);
   if (table->buckets == NULL)
     {
       /* out of memory, yay - just don't reallocate, the table will
        * still work, albeit more slowly.
        */
-      table->n_buckets /= 4;
       table->buckets = old_buckets;
       return;
     }
 
-  table->rebuild_size *= 4;
-  table->down_shift -= 2;
-  table->mask = (table->mask << 2) + 3;
+  table->n_buckets = new_buckets;
+  
+  if (growing)
+    {
+      table->lo_rebuild_size = table->hi_rebuild_size;
+      table->hi_rebuild_size *= 4;
+      
+      table->down_shift -= 2;               /* keep 2 more high bits */
+      table->mask = (table->mask << 2) + 3; /* keep 2 more high bits */
+    }
+  else
+    {
+      table->hi_rebuild_size = table->lo_rebuild_size;
+      table->lo_rebuild_size /= 4;
+
+      table->down_shift += 2;         /* keep 2 fewer high bits */
+      table->mask = table->mask >> 2; /* keep 2 fewer high bits */
+    }
 
+#if 0
+  printf ("%s table to lo = %d hi = %d downshift = %d mask = 0x%x\n",
+          growing ? "GROW" : "SHRINK",
+          table->lo_rebuild_size,
+          table->hi_rebuild_size,
+          table->down_shift,
+          table->mask);
+#endif
+  
+  _dbus_assert (table->lo_rebuild_size >= 0);
+  _dbus_assert (table->hi_rebuild_size > table->lo_rebuild_size);
+  _dbus_assert (table->mask != 0);
+  /* the mask is essentially the max index */
+  _dbus_assert (table->mask < table->n_buckets);
+  
   /*
    * Rehash all of the existing entries into the new bucket array.
    */
@@ -867,7 +947,7 @@ rebuild_table (DBusHashTable *table)
               _dbus_assert_not_reached ("Unknown hash table type");
               break;
             }
-
+          
           bucket = &(table->buckets[idx]);
           entry->next = *bucket;
           *bucket = entry;
@@ -1086,6 +1166,10 @@ _dbus_hash_table_get_n_entries (DBusHashTable *table)
 #include "dbus-test.h"
 #include <stdio.h>
 
+/* If you're wondering why the hash table test takes
+ * forever to run, it's because we call this function
+ * in inner loops thus making things quadratic.
+ */
 static int
 count_entries (DBusHashTable *table)
 {
@@ -1114,6 +1198,17 @@ _dbus_hash_test (void)
   DBusHashTable *table1;
   DBusHashTable *table2;
   DBusHashIter iter;
+#define N_HASH_KEYS 5000
+  char keys[N_HASH_KEYS][128];
+
+  printf ("Computing test hash keys...\n");
+  i = 0;
+  while (i < N_HASH_KEYS)
+    {
+      sprintf (keys[i], "Hash key %d", i); 
+      ++i;
+    }
+  printf ("... done.\n");
   
   table1 = _dbus_hash_table_new (DBUS_HASH_STRING,
                                  dbus_free, dbus_free);
@@ -1131,12 +1226,10 @@ _dbus_hash_test (void)
   i = 0;
   while (i < 3000)
     {
-      char buf[256];
-      sprintf (buf, "Hash key %d", i);
       void *value;
       char *key;
 
-      key = _dbus_strdup (buf);
+      key = _dbus_strdup (keys[i]);
       if (key == NULL)
         return FALSE;
       value = _dbus_strdup ("Value!");
@@ -1147,7 +1240,7 @@ _dbus_hash_test (void)
                                            key, value))
         return FALSE;
 
-      value = _dbus_strdup (buf);
+      value = _dbus_strdup (keys[i]);
       if (value == NULL)
         return FALSE;
       
@@ -1158,13 +1251,13 @@ _dbus_hash_test (void)
       _dbus_assert (count_entries (table1) == i + 1);
       _dbus_assert (count_entries (table2) == i + 1);
 
-      value = _dbus_hash_table_lookup_string (table1, buf);
+      value = _dbus_hash_table_lookup_string (table1, keys[i]);
       _dbus_assert (value != NULL);
       _dbus_assert (strcmp (value, "Value!") == 0);
 
       value = _dbus_hash_table_lookup_int (table2, i);
       _dbus_assert (value != NULL);
-      _dbus_assert (strcmp (value, buf) == 0);
+      _dbus_assert (strcmp (value, keys[i]) == 0);
       
       ++i;
     }
@@ -1172,11 +1265,8 @@ _dbus_hash_test (void)
   --i;
   while (i >= 0)
     {
-      char buf[256];
-      sprintf (buf, "Hash key %d", i);
-      
       _dbus_hash_table_remove_string (table1,
-                                      buf);
+                                      keys[i]);
 
       _dbus_hash_table_remove_int (table2, i);
 
@@ -1211,12 +1301,10 @@ _dbus_hash_test (void)
   i = 0;
   while (i < 5000)
     {
-      char buf[256];
-      sprintf (buf, "Hash key %d", i);
       char *key;
       void *value;      
       
-      key = _dbus_strdup (buf);
+      key = _dbus_strdup (keys[i]);
       if (key == NULL)
         return FALSE;
       value = _dbus_strdup ("Value!");
@@ -1227,7 +1315,7 @@ _dbus_hash_test (void)
                                            key, value))
         return FALSE;
 
-      value = _dbus_strdup (buf);
+      value = _dbus_strdup (keys[i]);
       if (value == NULL)
         return FALSE;
       
@@ -1297,7 +1385,60 @@ _dbus_hash_test (void)
       _dbus_assert (count_entries (table2) + 1 == i);
       --i;
     }
-  
+
+  /* add/remove interleaved, to check that we grow/shrink the table
+   * appropriately
+   */
+  i = 0;
+  while (i < 1000)
+    {
+      char *key;
+      void *value;
+            
+      key = _dbus_strdup (keys[i]);
+      if (key == NULL)
+        return FALSE;
+
+      value = _dbus_strdup ("Value!");
+      if (value == NULL)
+        return FALSE;
+      
+      if (!_dbus_hash_table_insert_string (table1,
+                                           key, value))
+        return FALSE;
+      
+      ++i;
+    }
+
+  --i;
+  while (i >= 0)
+    {
+      char *key;
+      void *value;      
+      
+      key = _dbus_strdup (keys[i]);
+      if (key == NULL)
+        return FALSE;
+      value = _dbus_strdup ("Value!");
+      if (value == NULL)
+        return FALSE;
+
+      if (!_dbus_hash_table_remove_string (table1, keys[i]))
+        return FALSE;
+      
+      if (!_dbus_hash_table_insert_string (table1,
+                                           key, value))
+        return FALSE;
+
+      if (!_dbus_hash_table_remove_string (table1, keys[i]))
+        return FALSE;
+      
+      _dbus_assert (_dbus_hash_table_get_n_entries (table1) == i);
+      
+      --i;
+    }
+
+  /* nuke these tables */
   _dbus_hash_table_unref (table1);
   _dbus_hash_table_unref (table2);
 
@@ -1318,12 +1459,10 @@ _dbus_hash_test (void)
   i = 0;
   while (i < 3000)
     {
-      char buf[256];
-      sprintf (buf, "Hash key %d", i);
       void *value;
       char *key;
 
-      key = _dbus_strdup (buf);
+      key = _dbus_strdup (keys[i]);
       if (key == NULL)
         return FALSE;
       value = _dbus_strdup ("Value!");
@@ -1336,7 +1475,7 @@ _dbus_hash_test (void)
       _dbus_assert (_dbus_hash_iter_get_value (&iter) == NULL);
       _dbus_hash_iter_set_value (&iter, value);
 
-      value = _dbus_strdup (buf);
+      value = _dbus_strdup (keys[i]);
       if (value == NULL)
         return FALSE;
 
@@ -1349,7 +1488,7 @@ _dbus_hash_test (void)
       _dbus_assert (count_entries (table1) == i + 1);
       _dbus_assert (count_entries (table2) == i + 1);
 
-      if (!_dbus_hash_iter_lookup (table1, buf, FALSE, &iter))
+      if (!_dbus_hash_iter_lookup (table1, keys[i], FALSE, &iter))
         return FALSE;
       
       value = _dbus_hash_iter_get_value (&iter);
@@ -1367,7 +1506,7 @@ _dbus_hash_test (void)
 
       value = _dbus_hash_iter_get_value (&iter);
       _dbus_assert (value != NULL);
-      _dbus_assert (strcmp (value, buf) == 0);
+      _dbus_assert (strcmp (value, keys[i]) == 0);
 
       /* Iterate just to be sure it works, though
        * it's a stupid thing to do
@@ -1381,10 +1520,7 @@ _dbus_hash_test (void)
   --i;
   while (i >= 0)
     {
-      char buf[256];
-      sprintf (buf, "Hash key %d", i);
-
-      if (!_dbus_hash_iter_lookup (table1, buf, FALSE, &iter))
+      if (!_dbus_hash_iter_lookup (table1, keys[i], FALSE, &iter))
         _dbus_assert_not_reached ("hash entry should have existed");
       _dbus_hash_iter_remove_entry (&iter);
       
diff --git a/dbus/dbus-list.c b/dbus/dbus-list.c
index 31e5ae3f..c36246cb 100644
--- a/dbus/dbus-list.c
+++ b/dbus/dbus-list.c
@@ -133,7 +133,7 @@ link_after (DBusList **list,
  * while (link != NULL)
  *   {
  *     printf ("value is %p\n", link->data);
- *     link = _dbus_list_get_next_link (&list);
+ *     link = _dbus_list_get_next_link (&link);
  *   }
  * @endcode
  *
@@ -155,7 +155,7 @@ link_after (DBusList **list,
  * while (link != NULL)
  *   {
  *     printf ("value is %p\n", link->data);
- *     link = _dbus_list_get_prev_link (&list);
+ *     link = _dbus_list_get_prev_link (&link);
  *   }
  * @endcode
  *
@@ -301,6 +301,37 @@ _dbus_list_remove (DBusList **list,
 }
 
 /**
+ * Removes a value from the list. Only removes the
+ * last value equal to the given data pointer,
+ * even if multiple values exist which match.
+ * This is a linear-time operation.
+ *
+ * @param list address of the list head.
+ * @param data the value to remove.
+ * @returns #TRUE if a value was found to remove.
+ */
+dbus_bool_t
+_dbus_list_remove_last (DBusList **list,
+                        void      *data)
+{
+  DBusList *link;
+
+  link = _dbus_list_get_last_link (list);
+  while (link != NULL)
+    {
+      if (link->data == data)
+        {
+          _dbus_list_remove_link (list, link);
+          return TRUE;
+        }
+      
+      link = _dbus_list_get_prev_link (list, link);
+    }
+
+  return FALSE;
+}
+
+/**
  * Removes a link from the list. This is a constant-time operation.
  *
  * @param list address of the list head.
diff --git a/dbus/dbus-list.h b/dbus/dbus-list.h
index 8de40002..ce8956a4 100644
--- a/dbus/dbus-list.h
+++ b/dbus/dbus-list.h
@@ -51,6 +51,8 @@ dbus_bool_t _dbus_list_insert_after   (DBusList **list,
                                        void      *data);
 dbus_bool_t _dbus_list_remove         (DBusList **list,
                                        void      *data);
+dbus_bool_t _dbus_list_remove_last    (DBusList **list,
+                                       void      *data);
 void        _dbus_list_remove_link    (DBusList **list,
                                        DBusList  *link);
 void        _dbus_list_clear          (DBusList **list);
diff --git a/dbus/dbus-mempool.c b/dbus/dbus-mempool.c
new file mode 100644
index 00000000..a3aa086d
--- /dev/null
+++ b/dbus/dbus-mempool.c
@@ -0,0 +1,454 @@
+/* -*- mode: C; c-file-style: "gnu" -*- */
+/* dbus-mempool.h Memory pools
+ * 
+ * Copyright (C) 2002  Red Hat, Inc.
+ *
+ * Licensed under the Academic Free License version 1.2
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+
+#include "dbus-mempool.h"
+
+/**
+ * @defgroup DBusMemPool memory pools
+ * @ingroup  DBusInternals
+ * @brief DBusMemPool object
+ *
+ * Types and functions related to DBusMemPool.  A memory pool is used
+ * to decrease memory fragmentation/overhead and increase speed for
+ * blocks of small uniformly-sized objects. The main point is to avoid
+ * the overhead of a malloc block for each small object, speed is
+ * secondary.
+ */
+
+/**
+ * @defgroup DBusMemPoolInternals Memory pool implementation details
+ * @ingroup  DBusInternals
+ * @brief DBusMemPool implementation details
+ *
+ * The guts of DBusMemPool.
+ *
+ * @{
+ */
+
+/**
+ * typedef so DBusFreedElement struct can refer to itself.
+ */
+typedef struct DBusFreedElement DBusFreedElement;
+
+/**
+ * struct representing an element on the free list.
+ * We just cast freed elements to this so we can
+ * make a list out of them.
+ */
+struct DBusFreedElement
+{
+  DBusFreedElement *next; /**< next element of the free list */
+};
+
+/**
+ * The dummy size of the variable-length "elements"
+ * field in DBusMemBlock
+ */
+#define ELEMENT_PADDING 4
+
+/**
+ * Typedef for DBusMemBlock so the struct can recursively
+ * point to itself.
+ */
+typedef struct DBusMemBlock DBusMemBlock;
+
+/**
+ * DBusMemBlock object represents a single malloc()-returned
+ * block that gets chunked up into objects in the memory pool.
+ */
+struct DBusMemBlock
+{
+  DBusMemBlock *next;  /**< next block in the list, which is already used up;
+                        *   only saved so we can free all the blocks
+                        *   when we free the mem pool.
+                        */
+
+  int used_so_far;     /**< bytes of this block already allocated as elements. */
+  
+  unsigned char elements[ELEMENT_PADDING]; /**< the block data, actually allocated to required size */
+};
+
+/**
+ * Internals fields of DBusMemPool
+ */
+struct DBusMemPool
+{
+  int element_size;                /**< size of a single object in the pool */
+  int block_size;                  /**< size of most recently allocated block */
+  unsigned int zero_elements : 1;  /**< whether to zero-init allocated elements */
+
+  DBusFreedElement *free_elements; /**< a free list of elements to recycle */
+  DBusMemBlock *blocks;            /**< blocks of memory from malloc() */
+};
+
+/** @} */
+
+/**
+ * @addtogroup DBusMemPool
+ *
+ * @{
+ */
+
+/**
+ * @typedef DBusMemPool
+ *
+ * Opaque object representing a memory pool. Memory pools allow
+ * avoiding per-malloc-block memory overhead when allocating a lot of
+ * small objects that are all the same size. They are slightly
+ * faster than calling malloc() also.
+ */
+
+/**
+ * Creates a new memory pool, or returns #NULL on failure.  Objects in
+ * the pool must be at least sizeof(void*) bytes each, due to the way
+ * memory pools work. To avoid creating 64 bit problems, this means at
+ * least 8 bytes on all platforms, unless you are 4 bytes on 32-bit
+ * and 8 bytes on 64-bit.
+ *
+ * @param element_size size of an element allocated from the pool.
+ * @param zero_elements whether to zero-initialize elements
+ * @returns the new pool or #NULL
+ */
+DBusMemPool*
+_dbus_mem_pool_new (int element_size,
+                    dbus_bool_t zero_elements)
+{
+  DBusMemPool *pool;
+
+  pool = dbus_new0 (DBusMemPool, 1);
+  if (pool == NULL)
+    return NULL;
+
+  /* these assertions are equivalent but the first is more clear
+   * to programmers that see it fail.
+   */
+  _dbus_assert (element_size >= (int) sizeof (void*));
+  _dbus_assert (element_size >= (int) sizeof (DBusFreedElement));
+  
+  pool->element_size = element_size;
+  pool->zero_elements = zero_elements != FALSE;
+
+  /* pick a size for the first block; it increases
+   * for each block we need to allocate. This is
+   * actually half the initial block size
+   * since _dbus_mem_pool_alloc() unconditionally
+   * doubles it prior to creating a new block.
+   */
+  pool->block_size = element_size * 8;
+
+  _dbus_assert ((pool->block_size %
+                 pool->element_size) == 0);
+  
+  return pool;
+}
+
+/**
+ * Frees a memory pool (and all elements allocated from it).
+ *
+ * @param pool the memory pool.
+ */
+void
+_dbus_mem_pool_free (DBusMemPool *pool)
+{
+  DBusMemBlock *block;
+
+  block = pool->blocks;
+  while (block != NULL)
+    {
+      DBusMemBlock *next = block->next;
+
+      dbus_free (block);
+
+      block = next;
+    }
+
+  dbus_free (pool);
+}
+
+/**
+ * Allocates an object from the memory pool.
+ * The object must be freed with _dbus_mem_pool_dealloc().
+ *
+ * @param pool the memory pool
+ * @returns the allocated object or #NULL if no memory.
+ */
+void*
+_dbus_mem_pool_alloc (DBusMemPool *pool)
+{
+  if (pool->free_elements)
+    {
+      DBusFreedElement *element = pool->free_elements;
+
+      pool->free_elements = pool->free_elements->next;
+
+      if (pool->zero_elements)
+        memset (element, '\0', pool->element_size);
+      
+      return element;
+    }
+  else
+    {
+      void *element;
+      
+      if (pool->blocks == NULL ||
+          pool->blocks->used_so_far == pool->block_size)
+        {
+          /* Need a new block */
+          DBusMemBlock *block;
+          int alloc_size;
+
+          if (pool->block_size <= _DBUS_INT_MAX / 4) /* avoid overflow */
+            {
+              /* use a larger block size for our next block */
+              pool->block_size *= 2;
+              _dbus_assert ((pool->block_size %
+                             pool->element_size) == 0);
+            }
+
+          alloc_size = sizeof (DBusMemBlock) - ELEMENT_PADDING + pool->block_size;
+          
+          if (pool->zero_elements)
+            block = dbus_malloc0 (alloc_size);
+          else
+            block = dbus_malloc (alloc_size);
+
+          if (block == NULL)
+            return NULL;
+
+          block->used_so_far = 0;
+          block->next = pool->blocks;
+          pool->blocks = block;
+        }
+      
+      element = &pool->blocks->elements[pool->blocks->used_so_far];
+
+      pool->blocks->used_so_far += pool->element_size;
+
+      return element;
+    }
+}
+
+/**
+ * Deallocates an object previously created with
+ * _dbus_mem_pool_alloc(). The previous object
+ * must have come from this same pool.
+ * @param pool the memory pool
+ * @param element the element earlier allocated.
+ */
+void
+_dbus_mem_pool_dealloc (DBusMemPool *pool,
+                        void        *element)
+{
+  DBusFreedElement *freed;
+
+  freed = element;
+  freed->next = pool->free_elements;
+  pool->free_elements = freed;
+}
+
+/** @} */
+
+#ifdef DBUS_BUILD_TESTS
+#include "dbus-test.h"
+#include <stdio.h>
+#include <time.h>
+
+static void
+time_for_size (int size)
+{
+  int i;
+  int j;
+  clock_t start;
+  clock_t end;
+#define FREE_ARRAY_SIZE 512
+#define N_ITERATIONS FREE_ARRAY_SIZE * 512
+  void *to_free[FREE_ARRAY_SIZE];
+  DBusMemPool *pool;
+
+  printf ("Timings for size %d\n", size);
+  
+  printf (" malloc\n");
+  
+  start = clock ();
+  
+  i = 0;
+  j = 0;
+  while (i < N_ITERATIONS)
+    {
+      to_free[j] = dbus_malloc (size);
+      _dbus_assert (to_free[j] != NULL); /* in a real app of course this is wrong */
+
+      ++j;
+
+      if (j == FREE_ARRAY_SIZE)
+        {
+          j = 0;
+          while (j < FREE_ARRAY_SIZE)
+            {
+              dbus_free (to_free[j]);
+              ++j;
+            }
+
+          j = 0;
+        }
+      
+      ++i;
+    }
+
+  end = clock ();
+
+  printf ("  created/destroyed %d elements in %g seconds\n",
+          N_ITERATIONS, (end - start) / (double) CLOCKS_PER_SEC);
+
+
+
+  printf (" mempools\n");
+  
+  start = clock ();
+
+  pool = _dbus_mem_pool_new (size, FALSE);
+  
+  i = 0;
+  j = 0;
+  while (i < N_ITERATIONS)
+    {
+      to_free[j] = _dbus_mem_pool_alloc (pool); 
+      _dbus_assert (to_free[j] != NULL);  /* in a real app of course this is wrong */
+
+      ++j;
+
+      if (j == FREE_ARRAY_SIZE)
+        {
+          j = 0;
+          while (j < FREE_ARRAY_SIZE)
+            {
+              _dbus_mem_pool_dealloc (pool, to_free[j]);
+              ++j;
+            }
+
+          j = 0;
+        }
+      
+      ++i;
+    }
+
+  _dbus_mem_pool_free (pool);
+  
+  end = clock ();
+
+  printf ("  created/destroyed %d elements in %g seconds\n",
+          N_ITERATIONS, (end - start) / (double) CLOCKS_PER_SEC);
+
+  printf (" zeroed malloc\n");
+    
+  start = clock ();
+  
+  i = 0;
+  j = 0;
+  while (i < N_ITERATIONS)
+    {
+      to_free[j] = dbus_malloc0 (size);
+      _dbus_assert (to_free[j] != NULL); /* in a real app of course this is wrong */
+
+      ++j;
+
+      if (j == FREE_ARRAY_SIZE)
+        {
+          j = 0;
+          while (j < FREE_ARRAY_SIZE)
+            {
+              dbus_free (to_free[j]);
+              ++j;
+            }
+
+          j = 0;
+        }
+      
+      ++i;
+    }
+
+  end = clock ();
+
+  printf ("  created/destroyed %d elements in %g seconds\n",
+          N_ITERATIONS, (end - start) / (double) CLOCKS_PER_SEC);
+  
+  printf (" zeroed mempools\n");
+  
+  start = clock ();
+
+  pool = _dbus_mem_pool_new (size, TRUE);
+  
+  i = 0;
+  j = 0;
+  while (i < N_ITERATIONS)
+    {
+      to_free[j] = _dbus_mem_pool_alloc (pool); 
+      _dbus_assert (to_free[j] != NULL);  /* in a real app of course this is wrong */
+
+      ++j;
+
+      if (j == FREE_ARRAY_SIZE)
+        {
+          j = 0;
+          while (j < FREE_ARRAY_SIZE)
+            {
+              _dbus_mem_pool_dealloc (pool, to_free[j]);
+              ++j;
+            }
+
+          j = 0;
+        }
+      
+      ++i;
+    }
+
+  _dbus_mem_pool_free (pool);
+  
+  end = clock ();
+
+  printf ("  created/destroyed %d elements in %g seconds\n",
+          N_ITERATIONS, (end - start) / (double) CLOCKS_PER_SEC);
+}
+
+/**
+ * @ingroup DBusMemPoolInternals
+ * Unit test for DBusMemPool
+ * @returns #TRUE on success.
+ */
+dbus_bool_t
+_dbus_mem_pool_test (void)
+{
+  int i;
+  int element_sizes[] = { 4, 8, 16, 50, 124 };
+  
+  i = 0;
+  while (i < _DBUS_N_ELEMENTS (element_sizes))
+    {
+      time_for_size (element_sizes[i]);
+      ++i;
+    }
+  
+  return TRUE;
+}
+
+#endif /* DBUS_BUILD_TESTS */
diff --git a/dbus/dbus-mempool.h b/dbus/dbus-mempool.h
new file mode 100644
index 00000000..17cfa309
--- /dev/null
+++ b/dbus/dbus-mempool.h
@@ -0,0 +1,44 @@
+/* -*- mode: C; c-file-style: "gnu" -*- */
+/* dbus-mempool.h Memory pools
+ * 
+ * Copyright (C) 2002  Red Hat, Inc.
+ *
+ * Licensed under the Academic Free License version 1.2
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+
+#ifndef DBUS_MEMPOOL_H
+#define DBUS_MEMPOOL_H
+
+#include <dbus/dbus-internals.h>
+#include <dbus/dbus-memory.h>
+#include <dbus/dbus-types.h>
+
+DBUS_BEGIN_DECLS;
+
+typedef struct DBusMemPool DBusMemPool;
+
+DBusMemPool* _dbus_mem_pool_new     (int          element_size,
+                                     dbus_bool_t  zero_elements);
+void         _dbus_mem_pool_free    (DBusMemPool *pool);
+void*        _dbus_mem_pool_alloc   (DBusMemPool *pool);
+void         _dbus_mem_pool_dealloc (DBusMemPool *pool,
+                                     void        *element);
+
+DBUS_END_DECLS;
+
+#endif /* DBUS_MEMPOOL_H */
diff --git a/dbus/dbus-message-handler.c b/dbus/dbus-message-handler.c
new file mode 100644
index 00000000..5f12d238
--- /dev/null
+++ b/dbus/dbus-message-handler.c
@@ -0,0 +1,265 @@
+/* -*- mode: C; c-file-style: "gnu" -*- */
+/* dbus-message-handler.c Sender/receiver of messages.
+ *
+ * Copyright (C) 2002  Red Hat Inc.
+ *
+ * Licensed under the Academic Free License version 1.2
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+
+#include "dbus-internals.h"
+#include "dbus-message-handler.h"
+#include "dbus-list.h"
+#include "dbus-connection-internal.h"
+
+/**
+ * @defgroup DBusMessageHandlerInternals DBusMessageHandler implementation details
+ * @ingroup DBusInternals
+ * @brief DBusMessageHandler private implementation details.
+ *
+ * The guts of DBusMessageHandler and its methods.
+ *
+ * @{
+ */
+
+
+/**
+ * @brief Internals of DBusMessageHandler
+ * 
+ * Object that can send and receive messages.
+ */
+struct DBusMessageHandler
+{
+  int refcount;                                   /**< reference count */
+
+  DBusHandleMessageFunction function;             /**< handler function */
+  void                     *user_data;            /**< user data for function */
+  DBusFreeFunction          free_user_data;       /**< free the user data */
+
+  DBusList *connections;                          /**< connections we're registered with */
+};
+
+/**
+ * Add this connection to the list used by this message handler.
+ * When the message handler goes away, the connection
+ * will be notified.
+ *
+ * @param handler the message handler
+ * @param connection the connection
+ * @returns #FALSE if not enough memory
+ */
+dbus_bool_t
+_dbus_message_handler_add_connection (DBusMessageHandler *handler,
+                                      DBusConnection     *connection)
+{
+  /* This is a bit wasteful - we just put the connection in the list
+   * once per time it's added. :-/
+   */
+  if (!_dbus_list_prepend (&handler->connections, connection))
+    return FALSE;
+
+  return TRUE;
+}
+
+/**
+ * Reverses the effect of _dbus_message_handler_add_connection().
+ * @param handler the message handler
+ * @param connection the connection
+ */
+void
+_dbus_message_handler_remove_connection (DBusMessageHandler *handler,
+                                         DBusConnection     *connection)
+{
+  if (!_dbus_list_remove (&handler->connections, connection))
+    _dbus_warn ("Function _dbus_message_handler_remove_connection() called when the connection hadn't been added\n");
+}
+
+
+/**
+ * Handles the given message, by dispatching the handler function
+ * for this DBusMessageHandler, if any.
+ * 
+ * @param handler the handler
+ * @param connection the connection that received the message
+ * @param message the message
+ *
+ * @returns what to do with the message
+ */
+DBusHandlerResult
+_dbus_message_handler_handle_message (DBusMessageHandler        *handler,
+                                      DBusConnection            *connection,
+                                      DBusMessage               *message)
+{
+  /* This function doesn't ref handler/connection/message
+   * since that's done in dbus_connection_dispatch_message().
+   */
+  if (handler->function != NULL)
+    return (* handler->function) (handler, connection, message, handler->user_data);
+  else
+    return DBUS_HANDLER_RESULT_ALLOW_MORE_HANDLERS;
+}
+
+/** @} */
+
+/**
+ * @defgroup DBusMessageHandler DBusMessageHandler
+ * @ingroup  DBus
+ * @brief Message processor  
+ *
+ * A DBusMessageHandler is an object that can send and receive
+ * messages. Typically the handler is registered with one or
+ * more DBusConnection objects and processes some types of
+ * messages received from the connection.
+ *
+ * @{
+ */
+
+/**
+ * @typedef DBusMessageHandler
+ *
+ * Opaque data type representing a message handler.
+ */
+
+/**
+ * Creates a new message handler. The handler function
+ * may be #NULL for a no-op handler or a handler to
+ * be assigned a function later.
+ *
+ * @param function function to call to handle a message
+ * @param user_data data to pass to the function
+ * @param free_user_data function to call to free the user data
+ * @returns a new DBusMessageHandler or #NULL if no memory.
+ */
+DBusMessageHandler*
+dbus_message_handler_new (DBusHandleMessageFunction function,
+                          void                     *user_data,
+                          DBusFreeFunction          free_user_data)
+{
+  DBusMessageHandler *handler;
+
+  handler = dbus_new (DBusMessageHandler, 1);
+
+  if (handler == NULL)
+    return NULL;
+  
+  handler->refcount = 1;
+  handler->function = function;
+  handler->user_data = user_data;
+  handler->free_user_data = free_user_data;
+  handler->connections = NULL;
+
+  return handler;
+}
+
+/**
+ * Increments the reference count on a message handler.
+ *
+ * @param handler the handler
+ */
+void
+dbus_message_handler_ref (DBusMessageHandler *handler)
+{
+  _dbus_assert (handler != NULL);
+  
+  handler->refcount += 1;
+}
+
+/**
+ * Decrements the reference count on a message handler,
+ * freeing the handler if the count reaches 0.
+ *
+ * @param handler the handler
+ */
+void
+dbus_message_handler_unref (DBusMessageHandler *handler)
+{
+  _dbus_assert (handler != NULL);
+  _dbus_assert (handler->refcount > 0);
+
+  handler->refcount -= 1;
+  if (handler->refcount == 0)
+    {
+      DBusList *link;
+      
+      if (handler->free_user_data)
+        (* handler->free_user_data) (handler->user_data);
+       
+      link = _dbus_list_get_first_link (&handler->connections);
+       while (link != NULL)
+         {
+           DBusConnection *connection = link->data;
+
+           _dbus_connection_handler_destroyed (connection, handler);
+           
+           link = _dbus_list_get_next_link (&handler->connections, link);
+         }
+
+       _dbus_list_clear (&handler->connections);
+
+       dbus_free (handler);
+    }
+}
+
+/**
+ * Gets the user data for the handler (the same user data
+ * passed to the handler function.)
+ *
+ * @param handler the handler
+ * @returns the user data
+ */
+void*
+dbus_message_handler_get_data (DBusMessageHandler *handler)
+{
+  return handler->user_data;
+}
+
+/**
+ * Sets the user data for the handler (the same user data
+ * to be passed to the handler function). Frees any previously-existing
+ * user data with the previous free_user_data function.
+ *
+ * @param handler the handler
+ * @param user_data the user data
+ * @param free_user_data free function for the data
+ */
+void
+dbus_message_handler_set_data (DBusMessageHandler *handler,
+                               void               *user_data,
+                               DBusFreeFunction    free_user_data)
+{
+  if (handler->free_user_data)
+    (* handler->free_user_data) (handler->user_data);
+
+  handler->user_data = user_data;
+  handler->free_user_data = free_user_data;
+}
+
+/**
+ * Sets the handler function. Call dbus_message_handler_set_data()
+ * to set the user data for the function.
+ *
+ * @param handler the handler
+ * @param function the function
+ */
+void
+dbus_message_handler_set_function (DBusMessageHandler        *handler,
+                                   DBusHandleMessageFunction  function)
+{
+  handler->function = function;
+}
+
+/** @} */
diff --git a/dbus/dbus-message-handler.h b/dbus/dbus-message-handler.h
new file mode 100644
index 00000000..dac015ac
--- /dev/null
+++ b/dbus/dbus-message-handler.h
@@ -0,0 +1,59 @@
+/* -*- mode: C; c-file-style: "gnu" -*- */
+/* dbus-message-handler.h Sender/receiver of messages.
+ *
+ * Copyright (C) 2002  Red Hat Inc.
+ *
+ * Licensed under the Academic Free License version 1.2
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+#if !defined (DBUS_INSIDE_DBUS_H) && !defined (DBUS_COMPILATION)
+#error "Only <dbus/dbus.h> can be included directly, this file may disappear or change contents."
+#endif
+
+#ifndef DBUS_MESSAGE_HANDLER_H
+#define DBUS_MESSAGE_HANDLER_H
+
+#include <dbus/dbus-macros.h>
+#include <dbus/dbus-types.h>
+#include <dbus/dbus-connection.h>
+
+DBUS_BEGIN_DECLS;
+
+typedef DBusHandlerResult (* DBusHandleMessageFunction) (DBusMessageHandler *handler,
+                                                         DBusConnection     *connection,
+                                                         DBusMessage        *message,
+                                                         void               *user_data);
+
+DBusMessageHandler* dbus_message_handler_new (DBusHandleMessageFunction  function,
+                                              void                      *user_data,
+                                              DBusFreeFunction           free_user_data);
+
+
+void         dbus_message_handler_ref   (DBusMessageHandler *handler);
+void         dbus_message_handler_unref (DBusMessageHandler *handler);
+
+
+void* dbus_message_handler_get_data       (DBusMessageHandler        *handler);
+void  dbus_message_handler_set_data       (DBusMessageHandler        *handler,
+                                           void                      *data,
+                                           DBusFreeFunction           free_user_data);
+void  dbus_message_handler_set_function   (DBusMessageHandler        *handler,
+                                           DBusHandleMessageFunction  function);
+
+DBUS_END_DECLS;
+
+#endif /* DBUS_MESSAGE_HANDLER_H */
diff --git a/dbus/dbus-message.c b/dbus/dbus-message.c
index d86f8318..62ac5eaf 100644
--- a/dbus/dbus-message.c
+++ b/dbus/dbus-message.c
@@ -200,6 +200,19 @@ dbus_message_unref (DBusMessage *message)
     }
 }
 
+/**
+ * Gets the name of a message.
+ * @param message the message
+ * @returns the message name (should not be freed)
+ */
+const char*
+dbus_message_get_name (DBusMessage *message)
+{
+  /* FIXME */
+  
+  return NULL;
+}
+
 /** @} */
 
 /**
diff --git a/dbus/dbus-message.h b/dbus/dbus-message.h
index 69d74e9c..ae8b84e1 100644
--- a/dbus/dbus-message.h
+++ b/dbus/dbus-message.h
@@ -39,6 +39,7 @@ DBusMessage* dbus_message_new   (void);
 void         dbus_message_ref   (DBusMessage *message);
 void         dbus_message_unref (DBusMessage *message);
 
+const char*  dbus_message_get_name (DBusMessage *message);
 
 DBUS_END_DECLS;
 
diff --git a/dbus/dbus-string.c b/dbus/dbus-string.c
index 573ed313..2b8d1349 100644
--- a/dbus/dbus-string.c
+++ b/dbus/dbus-string.c
@@ -1200,9 +1200,9 @@ _dbus_string_test (void)
 
   _dbus_assert (v == 27);
   _dbus_assert (end == i);
-    
-  _dbus_string_set_length (&str, 0);
 
+  _dbus_string_free (&str);
+  
   if (!_dbus_string_init (&str, _DBUS_INT_MAX))
     _dbus_assert_not_reached ("failed to init string");
   
diff --git a/dbus/dbus-test.c b/dbus/dbus-test.c
index c1514246..df840a7c 100644
--- a/dbus/dbus-test.c
+++ b/dbus/dbus-test.c
@@ -24,23 +24,35 @@
 #include "dbus-types.h"
 #include "dbus-test.h"
 #include <stdio.h>
+#include <stdlib.h>
+
+static void
+die (const char *failure)
+{
+  fprintf (stderr, "Failed: %s\n", failure);
+  exit (1);
+}
 
 int
 main (int    argc,
       char **argv)
 {
 
+  printf ("%s: running memory pool tests\n", argv[0]);
+  if (!_dbus_mem_pool_test ())
+    die ("memory pools");
+  
   printf ("%s: running string tests\n", argv[0]);
   if (!_dbus_string_test ())
-    return 1;
+    die ("strings");
   
   printf ("%s: running linked list tests\n", argv[0]);
   if (!_dbus_list_test ())
-    return 1;
+    die ("lists");
 
   printf ("%s: running hash table tests\n", argv[0]);
   if (!_dbus_hash_test ())
-    return 1;
+    die ("hash tables");
   
   printf ("%s: completed successfully\n", argv[0]);
   return 0;
diff --git a/dbus/dbus-test.h b/dbus/dbus-test.h
index 0df49738..80e0204c 100644
--- a/dbus/dbus-test.h
+++ b/dbus/dbus-test.h
@@ -26,8 +26,10 @@
 
 #include <dbus/dbus-types.h>
 
-dbus_bool_t _dbus_hash_test   (void);
-dbus_bool_t _dbus_list_test   (void);
-dbus_bool_t _dbus_string_test (void);
+dbus_bool_t _dbus_hash_test     (void);
+dbus_bool_t _dbus_list_test     (void);
+dbus_bool_t _dbus_mem_pool_test (void);
+dbus_bool_t _dbus_string_test   (void);
+
 
 #endif /* DBUS_TEST_H */
diff --git a/dbus/dbus.h b/dbus/dbus.h
index 6dc14dc6..fc4f2557 100644
--- a/dbus/dbus.h
+++ b/dbus/dbus.h
@@ -30,6 +30,7 @@
 #include <dbus/dbus-errors.h>
 #include <dbus/dbus-macros.h>
 #include <dbus/dbus-message.h>
+#include <dbus/dbus-message-handler.h>
 #include <dbus/dbus-server.h>
 #include <dbus/dbus-threads.h>
 #include <dbus/dbus-types.h>