1/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
2/* dbus-threads.h D-Bus threads handling
3 *
4 * Copyright (C) 2002 Red Hat Inc.
5 *
6 * Licensed under the Academic Free License version 2.1
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 *
22 */
23#if !defined (DBUS_INSIDE_DBUS_H) && !defined (DBUS_COMPILATION)
24#error "Only <dbus/dbus.h> can be included directly, this file may disappear or change contents."
25#endif
26
27#ifndef DBUS_THREADS_H
28#define DBUS_THREADS_H
29
30#include <dbus/dbus-macros.h>
31#include <dbus/dbus-types.h>
32
33DBUS_BEGIN_DECLS
34
35/**
36 * @addtogroup DBusThreads
37 * @{
38 */
39
40/** An opaque mutex type provided by the #DBusThreadFunctions implementation installed by dbus_threads_init(). */
41typedef struct DBusMutex DBusMutex;
42/** An opaque condition variable type provided by the #DBusThreadFunctions implementation installed by dbus_threads_init(). */
43typedef struct DBusCondVar DBusCondVar;
44
45/** Deprecated, provide DBusRecursiveMutexNewFunction instead. */
46typedef DBusMutex* (* DBusMutexNewFunction) (void);
47/** Deprecated, provide DBusRecursiveMutexFreeFunction instead. */
48typedef void (* DBusMutexFreeFunction) (DBusMutex *mutex);
49/** Deprecated, provide DBusRecursiveMutexLockFunction instead. Return value is lock success, but gets ignored in practice. */
50typedef dbus_bool_t (* DBusMutexLockFunction) (DBusMutex *mutex);
51/** Deprecated, provide DBusRecursiveMutexUnlockFunction instead. Return value is unlock success, but gets ignored in practice. */
52typedef dbus_bool_t (* DBusMutexUnlockFunction) (DBusMutex *mutex);
53
54/** Creates a new recursively-lockable mutex, or returns #NULL if not
55 * enough memory. Can only fail due to lack of memory. Found in
56 * #DBusThreadFunctions. Do not just use PTHREAD_MUTEX_RECURSIVE for
57 * this, because it does not save/restore the recursion count when
58 * waiting on a condition. libdbus requires the Java-style behavior
59 * where the mutex is fully unlocked to wait on a condition.
60 */
61typedef DBusMutex* (* DBusRecursiveMutexNewFunction) (void);
62/** Frees a recursively-lockable mutex. Found in #DBusThreadFunctions.
63 */
64typedef void (* DBusRecursiveMutexFreeFunction) (DBusMutex *mutex);
65/** Locks a recursively-lockable mutex. Found in #DBusThreadFunctions.
66 * Can only fail due to lack of memory.
67 */
68typedef void (* DBusRecursiveMutexLockFunction) (DBusMutex *mutex);
69/** Unlocks a recursively-lockable mutex. Found in #DBusThreadFunctions.
70 * Can only fail due to lack of memory.
71 */
72typedef void (* DBusRecursiveMutexUnlockFunction) (DBusMutex *mutex);
73
74/** Creates a new condition variable. Found in #DBusThreadFunctions.
75 * Can only fail (returning #NULL) due to lack of memory.
76 */
77typedef DBusCondVar* (* DBusCondVarNewFunction) (void);
78/** Frees a condition variable. Found in #DBusThreadFunctions.
79 */
80typedef void (* DBusCondVarFreeFunction) (DBusCondVar *cond);
81
82/** Waits on a condition variable. Found in
83 * #DBusThreadFunctions. Must work with either a recursive or
84 * nonrecursive mutex, whichever the thread implementation
85 * provides. Note that PTHREAD_MUTEX_RECURSIVE does not work with
86 * condition variables (does not save/restore the recursion count) so
87 * don't try using simply pthread_cond_wait() and a
88 * PTHREAD_MUTEX_RECURSIVE to implement this, it won't work right.
89 *
90 * Has no error conditions. Must succeed if it returns.
91 */
92typedef void (* DBusCondVarWaitFunction) (DBusCondVar *cond,
93 DBusMutex *mutex);
94
95/** Waits on a condition variable with a timeout. Found in
96 * #DBusThreadFunctions. Returns #TRUE if the wait did not
97 * time out, and #FALSE if it did.
98 *
99 * Has no error conditions. Must succeed if it returns.
100 */
101typedef dbus_bool_t (* DBusCondVarWaitTimeoutFunction) (DBusCondVar *cond,
102 DBusMutex *mutex,
103 int timeout_milliseconds);
104/** Wakes one waiting thread on a condition variable. Found in #DBusThreadFunctions.
105 *
106 * Has no error conditions. Must succeed if it returns.
107 */
108typedef void (* DBusCondVarWakeOneFunction) (DBusCondVar *cond);
109
110/** Wakes all waiting threads on a condition variable. Found in #DBusThreadFunctions.
111 *
112 * Has no error conditions. Must succeed if it returns.
113 */
114typedef void (* DBusCondVarWakeAllFunction) (DBusCondVar *cond);
115
116/**
117 * Flags indicating which functions are present in #DBusThreadFunctions. Used to allow
118 * the library to detect older callers of dbus_threads_init() if new possible functions
119 * are added to #DBusThreadFunctions.
120 */
121typedef enum
122{
123 DBUS_THREAD_FUNCTIONS_MUTEX_NEW_MASK = 1 << 0,
124 DBUS_THREAD_FUNCTIONS_MUTEX_FREE_MASK = 1 << 1,
125 DBUS_THREAD_FUNCTIONS_MUTEX_LOCK_MASK = 1 << 2,
126 DBUS_THREAD_FUNCTIONS_MUTEX_UNLOCK_MASK = 1 << 3,
127 DBUS_THREAD_FUNCTIONS_CONDVAR_NEW_MASK = 1 << 4,
128 DBUS_THREAD_FUNCTIONS_CONDVAR_FREE_MASK = 1 << 5,
129 DBUS_THREAD_FUNCTIONS_CONDVAR_WAIT_MASK = 1 << 6,
130 DBUS_THREAD_FUNCTIONS_CONDVAR_WAIT_TIMEOUT_MASK = 1 << 7,
131 DBUS_THREAD_FUNCTIONS_CONDVAR_WAKE_ONE_MASK = 1 << 8,
132 DBUS_THREAD_FUNCTIONS_CONDVAR_WAKE_ALL_MASK = 1 << 9,
133 DBUS_THREAD_FUNCTIONS_RECURSIVE_MUTEX_NEW_MASK = 1 << 10,
134 DBUS_THREAD_FUNCTIONS_RECURSIVE_MUTEX_FREE_MASK = 1 << 11,
135 DBUS_THREAD_FUNCTIONS_RECURSIVE_MUTEX_LOCK_MASK = 1 << 12,
136 DBUS_THREAD_FUNCTIONS_RECURSIVE_MUTEX_UNLOCK_MASK = 1 << 13,
137 DBUS_THREAD_FUNCTIONS_ALL_MASK = (1 << 14) - 1
138} DBusThreadFunctionsMask;
139
140/**
141 * Functions that must be implemented to make the D-Bus library
142 * thread-aware.
143 *
144 * If you supply both recursive and non-recursive mutexes,
145 * libdbus will use the non-recursive version for condition variables,
146 * and the recursive version in other contexts.
147 *
148 * The condition variable functions have to work with nonrecursive
149 * mutexes if you provide those, or with recursive mutexes if you
150 * don't.
151 */
152typedef struct
153{
154 unsigned int mask; /**< Mask indicating which functions are present. */
155
156 DBusMutexNewFunction mutex_new; /**< Function to create a mutex; optional and deprecated. */
157 DBusMutexFreeFunction mutex_free; /**< Function to free a mutex; optional and deprecated. */
158 DBusMutexLockFunction mutex_lock; /**< Function to lock a mutex; optional and deprecated. */
159 DBusMutexUnlockFunction mutex_unlock; /**< Function to unlock a mutex; optional and deprecated. */
160
161 DBusCondVarNewFunction condvar_new; /**< Function to create a condition variable */
162 DBusCondVarFreeFunction condvar_free; /**< Function to free a condition variable */
163 DBusCondVarWaitFunction condvar_wait; /**< Function to wait on a condition */
164 DBusCondVarWaitTimeoutFunction condvar_wait_timeout; /**< Function to wait on a condition with a timeout */
165 DBusCondVarWakeOneFunction condvar_wake_one; /**< Function to wake one thread waiting on the condition */
166 DBusCondVarWakeAllFunction condvar_wake_all; /**< Function to wake all threads waiting on the condition */
167
168 DBusRecursiveMutexNewFunction recursive_mutex_new; /**< Function to create a recursive mutex */
169 DBusRecursiveMutexFreeFunction recursive_mutex_free; /**< Function to free a recursive mutex */
170 DBusRecursiveMutexLockFunction recursive_mutex_lock; /**< Function to lock a recursive mutex */
171 DBusRecursiveMutexUnlockFunction recursive_mutex_unlock; /**< Function to unlock a recursive mutex */
172
173 void (* padding1) (void); /**< Reserved for future expansion */
174 void (* padding2) (void); /**< Reserved for future expansion */
175 void (* padding3) (void); /**< Reserved for future expansion */
176 void (* padding4) (void); /**< Reserved for future expansion */
177
178} DBusThreadFunctions;
179
180DBUS_EXPORT
181dbus_bool_t dbus_threads_init (const DBusThreadFunctions *functions);
182DBUS_EXPORT
183dbus_bool_t dbus_threads_init_default (void);
184
185/** @} */
186
187DBUS_END_DECLS
188
189#endif /* DBUS_THREADS_H */
190