--- /dev/null
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
+/* dbus-watch.c DBusWatch implementation
+ *
+ * Copyright (C) 2002, 2003 Red Hat Inc.
+ *
+ * Licensed under the Academic Free License version 2.1
+ *
+ * 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-watch.h"
+#include "dbus-list.h"
+
+/**
+ * @defgroup DBusWatchInternals DBusWatch implementation details
+ * @ingroup DBusInternals
+ * @brief implementation details for DBusWatch
+ *
+ * @{
+ */
+
+/**
+ * Implementation of DBusWatch
+ */
+struct DBusWatch
+{
+ int refcount; /**< Reference count */
+ int fd; /**< File descriptor. */
+ unsigned int flags; /**< Conditions to watch. */
+
+ DBusWatchHandler handler; /**< Watch handler. */
+ void *handler_data; /**< Watch handler data. */
+ DBusFreeFunction free_handler_data_function; /**< Free the watch handler data. */
+
+ void *data; /**< Application data. */
+ DBusFreeFunction free_data_function; /**< Free the application data. */
+ unsigned int enabled : 1; /**< Whether it's enabled. */
+};
+
+/**
+ * Creates a new DBusWatch. Used to add a file descriptor to be polled
+ * by a main loop.
+ *
+ * @param fd the file descriptor to be watched.
+ * @param flags the conditions to watch for on the descriptor.
+ * @param enabled the initial enabled state
+ * @param handler the handler function
+ * @param data data for handler function
+ * @param free_data_function function to free the data
+ * @returns the new DBusWatch object.
+ */
+DBusWatch*
+_dbus_watch_new (int fd,
+ unsigned int flags,
+ dbus_bool_t enabled,
+ DBusWatchHandler handler,
+ void *data,
+ DBusFreeFunction free_data_function)
+{
+ DBusWatch *watch;
+
+#define VALID_WATCH_FLAGS (DBUS_WATCH_WRITABLE | DBUS_WATCH_READABLE)
+
+ _dbus_assert ((flags & VALID_WATCH_FLAGS) == flags);
+
+ watch = dbus_new0 (DBusWatch, 1);
+ if (watch == NULL)
+ return NULL;
+
+ watch->refcount = 1;
+ watch->fd = fd;
+ watch->flags = flags;
+ watch->enabled = enabled;
+
+ watch->handler = handler;
+ watch->handler_data = data;
+ watch->free_handler_data_function = free_data_function;
+
+ return watch;
+}
+
+/**
+ * Increments the reference count of a DBusWatch object.
+ *
+ * @param watch the watch object.
+ * @returns the watch object.
+ */
+DBusWatch *
+_dbus_watch_ref (DBusWatch *watch)
+{
+ watch->refcount += 1;
+
+ return watch;
+}
+
+/**
+ * Decrements the reference count of a DBusWatch object
+ * and finalizes the object if the count reaches zero.
+ *
+ * @param watch the watch object.
+ */
+void
+_dbus_watch_unref (DBusWatch *watch)
+{
+ _dbus_assert (watch != NULL);
+ _dbus_assert (watch->refcount > 0);
+
+ watch->refcount -= 1;
+ if (watch->refcount == 0)
+ {
+ dbus_watch_set_data (watch, NULL, NULL); /* call free_data_function */
+
+ if (watch->free_handler_data_function)
+ (* watch->free_handler_data_function) (watch->handler_data);
+
+ dbus_free (watch);
+ }
+}
+
+/**
+ * Clears the file descriptor from a now-invalid watch object so that
+ * no one tries to use it. This is because a watch may stay alive due
+ * to reference counts after the file descriptor is closed.
+ * Invalidation makes it easier to catch bugs. It also
+ * keeps people from doing dorky things like assuming file descriptors
+ * are unique (never recycled).
+ *
+ * @param watch the watch object.
+ */
+void
+_dbus_watch_invalidate (DBusWatch *watch)
+{
+ watch->fd = -1;
+ watch->flags = 0;
+}
+
+/**
+ * Sanitizes the given condition so that it only contains
+ * flags that the DBusWatch requested. e.g. if the
+ * watch is a DBUS_WATCH_READABLE watch then
+ * DBUS_WATCH_WRITABLE will be stripped from the condition.
+ *
+ * @param watch the watch object.
+ * @param condition address of the condition to sanitize.
+ */
+void
+_dbus_watch_sanitize_condition (DBusWatch *watch,
+ unsigned int *condition)
+{
+ if (!(watch->flags & DBUS_WATCH_READABLE))
+ *condition &= ~DBUS_WATCH_READABLE;
+ if (!(watch->flags & DBUS_WATCH_WRITABLE))
+ *condition &= ~DBUS_WATCH_WRITABLE;
+}
+
+
+/**
+ * @typedef DBusWatchList
+ *
+ * Opaque data type representing a list of watches
+ * and a set of DBusAddWatchFunction/DBusRemoveWatchFunction.
+ * Automatically handles removing/re-adding watches
+ * when the DBusAddWatchFunction is updated or changed.
+ * Holds a reference count to each watch.
+ *
+ * Used in the implementation of both DBusServer and
+ * DBusClient.
+ *
+ */
+
+/**
+ * DBusWatchList implementation details. All fields
+ * are private.
+ *
+ */
+struct DBusWatchList
+{
+ DBusList *watches; /**< Watch objects. */
+
+ DBusAddWatchFunction add_watch_function; /**< Callback for adding a watch. */
+ DBusRemoveWatchFunction remove_watch_function; /**< Callback for removing a watch. */
+ DBusWatchToggledFunction watch_toggled_function; /**< Callback on toggling enablement */
+ void *watch_data; /**< Data for watch callbacks */
+ DBusFreeFunction watch_free_data_function; /**< Free function for watch callback data */
+};
+
+/**
+ * Creates a new watch list. Returns #NULL if insufficient
+ * memory exists.
+ *
+ * @returns the new watch list, or #NULL on failure.
+ */
+DBusWatchList*
+_dbus_watch_list_new (void)
+{
+ DBusWatchList *watch_list;
+
+ watch_list = dbus_new0 (DBusWatchList, 1);
+ if (watch_list == NULL)
+ return NULL;
+
+ return watch_list;
+}
+
+/**
+ * Frees a DBusWatchList.
+ *
+ * @param watch_list the watch list.
+ */
+void
+_dbus_watch_list_free (DBusWatchList *watch_list)
+{
+ /* free watch_data and removes watches as a side effect */
+ _dbus_watch_list_set_functions (watch_list,
+ NULL, NULL, NULL, NULL, NULL);
+ _dbus_list_foreach (&watch_list->watches,
+ (DBusForeachFunction) _dbus_watch_unref,
+ NULL);
+ _dbus_list_clear (&watch_list->watches);
+
+ dbus_free (watch_list);
+}
+
+/**
+ * Sets the watch functions. This function is the "backend"
+ * for dbus_connection_set_watch_functions() and
+ * dbus_server_set_watch_functions().
+ *
+ * @param watch_list the watch list.
+ * @param add_function the add watch function.
+ * @param remove_function the remove watch function.
+ * @param toggled_function function on toggling enabled flag, or #NULL
+ * @param data the data for those functions.
+ * @param free_data_function the function to free the data.
+ * @returns #FALSE if not enough memory
+ *
+ */
+dbus_bool_t
+_dbus_watch_list_set_functions (DBusWatchList *watch_list,
+ DBusAddWatchFunction add_function,
+ DBusRemoveWatchFunction remove_function,
+ DBusWatchToggledFunction toggled_function,
+ void *data,
+ DBusFreeFunction free_data_function)
+{
+ /* Add watches with the new watch function, failing on OOM */
+ if (add_function != NULL)
+ {
+ DBusList *link;
+
+ link = _dbus_list_get_first_link (&watch_list->watches);
+ while (link != NULL)
+ {
+ DBusList *next = _dbus_list_get_next_link (&watch_list->watches,
+ link);
+
+#ifdef DBUS_ENABLE_VERBOSE_MODE
+ {
+ const char *watch_type;
+ int flags;
+
+ flags = dbus_watch_get_flags (link->data);
+ if ((flags & DBUS_WATCH_READABLE) &&
+ (flags & DBUS_WATCH_WRITABLE))
+ watch_type = "readwrite";
+ else if (flags & DBUS_WATCH_READABLE)
+ watch_type = "read";
+ else if (flags & DBUS_WATCH_WRITABLE)
+ watch_type = "write";
+ else
+ watch_type = "not read or write";
+
+ _dbus_verbose ("Adding a %s watch on fd %d using newly-set add watch function\n",
+ watch_type,
+ dbus_watch_get_socket (link->data));
+ }
+#endif /* DBUS_ENABLE_VERBOSE_MODE */
+
+ if (!(* add_function) (link->data, data))
+ {
+ /* remove it all again and return FALSE */
+ DBusList *link2;
+
+ link2 = _dbus_list_get_first_link (&watch_list->watches);
+ while (link2 != link)
+ {
+ DBusList *next = _dbus_list_get_next_link (&watch_list->watches,
+ link2);
+
+ _dbus_verbose ("Removing watch on fd %d using newly-set remove function because initial add failed\n",
+ dbus_watch_get_socket (link2->data));
+
+ (* remove_function) (link2->data, data);
+
+ link2 = next;
+ }
+
+ return FALSE;
+ }
+
+ link = next;
+ }
+ }
+
+ /* Remove all current watches from previous watch handlers */
+
+ if (watch_list->remove_watch_function != NULL)
+ {
+ _dbus_verbose ("Removing all pre-existing watches\n");
+
+ _dbus_list_foreach (&watch_list->watches,
+ (DBusForeachFunction) watch_list->remove_watch_function,
+ watch_list->watch_data);
+ }
+
+ if (watch_list->watch_free_data_function != NULL)
+ (* watch_list->watch_free_data_function) (watch_list->watch_data);
+
+ watch_list->add_watch_function = add_function;
+ watch_list->remove_watch_function = remove_function;
+ watch_list->watch_toggled_function = toggled_function;
+ watch_list->watch_data = data;
+ watch_list->watch_free_data_function = free_data_function;
+
+ return TRUE;
+}
+
+/**
+ * Adds a new watch to the watch list, invoking the
+ * application DBusAddWatchFunction if appropriate.
+ *
+ * @param watch_list the watch list.
+ * @param watch the watch to add.
+ * @returns #TRUE on success, #FALSE if no memory.
+ */
+dbus_bool_t
+_dbus_watch_list_add_watch (DBusWatchList *watch_list,
+ DBusWatch *watch)
+{
+ if (!_dbus_list_append (&watch_list->watches, watch))
+ return FALSE;
+
+ _dbus_watch_ref (watch);
+
+ if (watch_list->add_watch_function != NULL)
+ {
+ _dbus_verbose ("Adding watch on fd %d\n",
+ dbus_watch_get_socket (watch));
+
+ if (!(* watch_list->add_watch_function) (watch,
+ watch_list->watch_data))
+ {
+ _dbus_list_remove_last (&watch_list->watches, watch);
+ _dbus_watch_unref (watch);
+ return FALSE;
+ }
+ }
+
+ return TRUE;
+}
+
+/**
+ * Removes a watch from the watch list, invoking the
+ * application's DBusRemoveWatchFunction if appropriate.
+ *
+ * @param watch_list the watch list.
+ * @param watch the watch to remove.
+ */
+void
+_dbus_watch_list_remove_watch (DBusWatchList *watch_list,
+ DBusWatch *watch)
+{
+ if (!_dbus_list_remove (&watch_list->watches, watch))
+ _dbus_assert_not_reached ("Nonexistent watch was removed");
+
+ if (watch_list->remove_watch_function != NULL)
+ {
+ _dbus_verbose ("Removing watch on fd %d\n",
+ dbus_watch_get_socket (watch));
+
+ (* watch_list->remove_watch_function) (watch,
+ watch_list->watch_data);
+ }
+
+ _dbus_watch_unref (watch);
+}
+
+/**
+ * Sets a watch to the given enabled state, invoking the
+ * application's DBusWatchToggledFunction if appropriate.
+ *
+ * @param watch_list the watch list.
+ * @param watch the watch to toggle.
+ * @param enabled #TRUE to enable
+ */
+void
+_dbus_watch_list_toggle_watch (DBusWatchList *watch_list,
+ DBusWatch *watch,
+ dbus_bool_t enabled)
+{
+ enabled = !!enabled;
+
+ if (enabled == watch->enabled)
+ return;
+
+ watch->enabled = enabled;
+
+ if (watch_list->watch_toggled_function != NULL)
+ {
+ _dbus_verbose ("Toggling watch %p on fd %d to %d\n",
+ watch, dbus_watch_get_socket (watch), watch->enabled);
+
+ (* watch_list->watch_toggled_function) (watch,
+ watch_list->watch_data);
+ }
+}
+
+/**
+ * Sets the handler for the watch.
+ *
+ * @todo this function only exists because of the weird
+ * way connection watches are done, see the note
+ * in docs for _dbus_connection_handle_watch().
+ *
+ * @param watch the watch
+ * @param handler the new handler
+ * @param data the data
+ * @param free_data_function free data with this
+ */
+void
+_dbus_watch_set_handler (DBusWatch *watch,
+ DBusWatchHandler handler,
+ void *data,
+ DBusFreeFunction free_data_function)
+{
+ if (watch->free_handler_data_function)
+ (* watch->free_handler_data_function) (watch->handler_data);
+
+ watch->handler = handler;
+ watch->handler_data = data;
+ watch->free_handler_data_function = free_data_function;
+}
+
+/** @} */
+
+/**
+ * @defgroup DBusWatch DBusWatch
+ * @ingroup DBus
+ * @brief Object representing a file descriptor to be watched.
+ *
+ * Types and functions related to DBusWatch. A watch represents
+ * a file descriptor that the main loop needs to monitor,
+ * as in Qt's QSocketNotifier or GLib's g_io_add_watch().
+ *
+ * Use dbus_connection_set_watch_functions() or dbus_server_set_watch_functions()
+ * to be notified when libdbus needs to add or remove watches.
+ *
+ * @{
+ */
+
+/**
+ * @typedef DBusWatch
+ *
+ * Opaque object representing a file descriptor
+ * to be watched for changes in readability,
+ * writability, or hangup.
+ */
+
+/**
+ * Deprecated former name of dbus_watch_get_unix_fd().
+ *
+ * @param watch the DBusWatch object.
+ * @returns the file descriptor to watch.
+ */
+int
+dbus_watch_get_fd (DBusWatch *watch)
+{
+ return dbus_watch_get_unix_fd(watch);
+}
+
+/**
+ * Returns a UNIX file descriptor to be watched,
+ * which may be a pipe, socket, or other type of
+ * descriptor. On UNIX this is preferred to
+ * dbus_watch_get_socket() since it works with
+ * more kinds of #DBusWatch.
+ *
+ * Always returns -1 on Windows. On Windows you use
+ * dbus_watch_get_socket() to get a Winsock socket to watch.
+ *
+ * @param watch the DBusWatch object.
+ * @returns the file descriptor to watch.
+ */
+int
+dbus_watch_get_unix_fd (DBusWatch *watch)
+{
+ /* FIXME remove #ifdef and do this on a lower level
+ * (watch should have set_socket and set_unix_fd and track
+ * which it has, and the transport should provide the
+ * appropriate watch type)
+ */
+#ifdef DBUS_UNIX
+ return watch->fd;
+#else
+ return -1;
+#endif
+}
+
+/**
+ * Returns a socket to be watched, on UNIX this will return -1 if our
+ * transport is not socket-based so dbus_watch_get_unix_fd() is
+ * preferred.
+ *
+ * On Windows, dbus_watch_get_unix_fd() returns -1 but this function
+ * returns a Winsock socket (assuming the transport is socket-based,
+ * as it always is for now).
+ *
+ * @param watch the DBusWatch object.
+ * @returns the socket to watch.
+ */
+int
+dbus_watch_get_socket (DBusWatch *watch)
+{
+ return watch->fd;
+}
+
+/**
+ * Gets flags from DBusWatchFlags indicating
+ * what conditions should be monitored on the
+ * file descriptor.
+ *
+ * The flags returned will only contain DBUS_WATCH_READABLE
+ * and DBUS_WATCH_WRITABLE, never DBUS_WATCH_HANGUP or
+ * DBUS_WATCH_ERROR; all watches implicitly include a watch
+ * for hangups, errors, and other exceptional conditions.
+ *
+ * @param watch the DBusWatch object.
+ * @returns the conditions to watch.
+ */
+unsigned int
+dbus_watch_get_flags (DBusWatch *watch)
+{
+ _dbus_assert ((watch->flags & VALID_WATCH_FLAGS) == watch->flags);
+
+ return watch->flags;
+}
+
+/**
+ * Gets data previously set with dbus_watch_set_data()
+ * or #NULL if none.
+ *
+ * @param watch the DBusWatch object.
+ * @returns previously-set data.
+ */
+void*
+dbus_watch_get_data (DBusWatch *watch)
+{
+ return watch->data;
+}
+
+/**
+ * Sets data which can be retrieved with dbus_watch_get_data().
+ * Intended for use by the DBusAddWatchFunction and
+ * DBusRemoveWatchFunction to store their own data. For example with
+ * Qt you might store the QSocketNotifier for this watch and with GLib
+ * you might store a GSource.
+ *
+ * @param watch the DBusWatch object.
+ * @param data the data.
+ * @param free_data_function function to be called to free the data.
+ */
+void
+dbus_watch_set_data (DBusWatch *watch,
+ void *data,
+ DBusFreeFunction free_data_function)
+{
+ _dbus_verbose ("Setting watch fd %d data to data = %p function = %p from data = %p function = %p\n",
+ dbus_watch_get_socket (watch),
+ data, free_data_function, watch->data, watch->free_data_function);
+
+ if (watch->free_data_function != NULL)
+ (* watch->free_data_function) (watch->data);
+
+ watch->data = data;
+ watch->free_data_function = free_data_function;
+}
+
+/**
+ * Returns whether a watch is enabled or not. If not
+ * enabled, it should not be polled by the main loop.
+ *
+ * @param watch the DBusWatch object
+ * @returns #TRUE if the watch is enabled
+ */
+dbus_bool_t
+dbus_watch_get_enabled (DBusWatch *watch)
+{
+ _dbus_assert (watch != NULL);
+ return watch->enabled;
+}
+
+
+/**
+ * Called to notify the D-Bus library when a previously-added watch is
+ * ready for reading or writing, or has an exception such as a hangup.
+ *
+ * If this function returns #FALSE, then the file descriptor may still
+ * be ready for reading or writing, but more memory is needed in order
+ * to do the reading or writing. If you ignore the #FALSE return, your
+ * application may spin in a busy loop on the file descriptor until
+ * memory becomes available, but nothing more catastrophic should
+ * happen.
+ *
+ * dbus_watch_handle() cannot be called during the
+ * DBusAddWatchFunction, as the connection will not be ready to handle
+ * that watch yet.
+ *
+ * It is not allowed to reference a DBusWatch after it has been passed
+ * to remove_function.
+ *
+ * @param watch the DBusWatch object.
+ * @param flags the poll condition using #DBusWatchFlags values
+ * @returns #FALSE if there wasn't enough memory
+ */
+dbus_bool_t
+dbus_watch_handle (DBusWatch *watch,
+ unsigned int flags)
+{
+#ifndef DBUS_DISABLE_CHECKS
+ if (watch->fd < 0 || watch->flags == 0)
+ {
+ _dbus_warn_check_failed ("%s: Watch is invalid, it should have been removed\n",
+ _DBUS_FUNCTION_NAME);
+ return TRUE;
+ }
+#endif
+
+ _dbus_return_val_if_fail (watch->fd >= 0 /* fails if watch was removed */, TRUE);
+
+ _dbus_watch_sanitize_condition (watch, &flags);
+
+ if (flags == 0)
+ {
+ _dbus_verbose ("After sanitization, watch flags on fd %d were 0\n",
+ watch->fd);
+ return TRUE;
+ }
+ else
+ return (* watch->handler) (watch, flags,
+ watch->handler_data);
+}
+
+
+/** @} */
projects / monky / blobdiff