glib/gthread.h

/* GLIB - Library of useful routines for C programming
 * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

/*
 * Modified by the GLib Team and others 1997-2000.  See the AUTHORS
 * file for a list of people on the GLib Team.  See the ChangeLog
 * files for a list of changes.  These files are distributed with
 * GLib at ftp://ftp.gtk.org/pub/gtk/. 
 */

#ifndef __G_THREAD_H__
#define __G_THREAD_H__

#include <gerror.h>
#include <gtypes.h>

G_BEGIN_DECLS

/* GLib Thread support
 */

extern GQuark g_thread_error_quark (void);
#define G_THREAD_ERROR g_thread_error_quark ()

typedef enum
{
  G_THREAD_ERROR_AGAIN /* Resource temporarily unavailable */
} GThreadError;

typedef void            (*GThreadFunc)          (gpointer       value);

typedef enum
{
  G_THREAD_PRIORITY_LOW,
  G_THREAD_PRIORITY_NORMAL,
  G_THREAD_PRIORITY_HIGH,
  G_THREAD_PRIORITY_URGENT
} GThreadPriority;

typedef struct _GThread         GThread;
struct  _GThread
{
  gboolean joinable;
  gboolean bound;
  GThreadPriority priority;
};

typedef struct _GMutex          GMutex;
typedef struct _GCond           GCond;
typedef struct _GPrivate        GPrivate;
typedef struct _GStaticPrivate  GStaticPrivate;

typedef struct _GThreadFunctions GThreadFunctions;
struct _GThreadFunctions
{
  GMutex*  (*mutex_new)           (void);
  void     (*mutex_lock)          (GMutex               *mutex);
  gboolean (*mutex_trylock)       (GMutex               *mutex);
  void     (*mutex_unlock)        (GMutex               *mutex);
  void     (*mutex_free)          (GMutex               *mutex);
  GCond*   (*cond_new)            (void);
  void     (*cond_signal)         (GCond                *cond);
  void     (*cond_broadcast)      (GCond                *cond);
  void     (*cond_wait)           (GCond                *cond,
                                   GMutex               *mutex);
  gboolean (*cond_timed_wait)     (GCond                *cond,
                                   GMutex               *mutex,
                                   GTimeVal             *end_time);
  void      (*cond_free)          (GCond                *cond);
  GPrivate* (*private_new)        (GDestroyNotify        destructor);
  gpointer  (*private_get)        (GPrivate             *private_key);
  void      (*private_set)        (GPrivate             *private_key,
                                   gpointer              data);
  void      (*thread_create)      (GThreadFunc           thread_func,
                                   gpointer              arg,
                                   gulong                stack_size,
                                   gboolean              joinable,
                                   gboolean              bound,
                                   GThreadPriority       priority,
                                   gpointer              thread,
                                   GError              **error);
  void      (*thread_yield)       (void);
  void      (*thread_join)        (gpointer              thread);
  void      (*thread_exit)        (void);
  void      (*thread_set_priority)(gpointer              thread,
                                   GThreadPriority       priority);
  void      (*thread_self)        (gpointer              thread);
};

GLIB_VAR GThreadFunctions       g_thread_functions_for_glib_use;
GLIB_VAR gboolean               g_thread_use_default_impl;
GLIB_VAR gboolean               g_threads_got_initialized;

/* initializes the mutex/cond/private implementation for glib, might
 * only be called once, and must not be called directly or indirectly
 * from another glib-function, e.g. as a callback.
 */
void    g_thread_init   (GThreadFunctions       *vtable);

/* Errorcheck mutexes. If you define G_ERRORCHECK_MUTEXES, then all
 * mutexes will check for re-locking and re-unlocking */

/* Initialize thread system with errorcheck mutexes. vtable must be
 * NULL. Do not call directly. Use #define G_ERRORCHECK_MUTEXES
 * instead.
 */
void    g_thread_init_with_errorcheck_mutexes (GThreadFunctions* vtable);

/* A random number to recognize debug calls to g_mutex_... */
#define G_MUTEX_DEBUG_MAGIC 0xf8e18ad7

#ifdef G_ERRORCHECK_MUTEXES
#define g_thread_init(vtable) g_thread_init_with_errorcheck_mutexes (vtable)
#endif

/* internal function for fallback static mutex implementation */
GMutex* g_static_mutex_get_mutex_impl   (GMutex **mutex);

/* shorthands for conditional and unconditional function calls */

#define G_THREAD_UF(op, arglist)					\
    (*g_thread_functions_for_glib_use . op) arglist
#define G_THREAD_CF(op, fail, arg)					\
    (g_thread_supported () ? G_THREAD_UF (op, arg) : (fail))
#define G_THREAD_ECF(op, fail, mutex, type)				\
    (g_thread_supported () ? ((type(*)(GMutex*, gulong, gchar*))	\
      (*g_thread_functions_for_glib_use . op))				\
     (mutex, G_MUTEX_DEBUG_MAGIC, G_STRLOC) : (fail))

#ifndef G_ERRORCHECK_MUTEXES
# define g_mutex_lock(mutex)						\
    G_THREAD_CF (mutex_lock,     (void)0, (mutex))
# define g_mutex_trylock(mutex)						\
    G_THREAD_CF (mutex_trylock,  TRUE,    (mutex))
# define g_mutex_unlock(mutex)						\
    G_THREAD_CF (mutex_unlock,   (void)0, (mutex))
# define g_mutex_free(mutex)						\
    G_THREAD_CF (mutex_free,     (void)0, (mutex))
# define g_cond_wait(cond, mutex)					\
    G_THREAD_CF (cond_wait,      (void)0, (cond, mutex))
# define g_cond_timed_wait(cond, mutex, abs_time)			\
    G_THREAD_CF (cond_timed_wait, TRUE,   (cond, mutex, abs_time))
#else /* G_ERRORCHECK_MUTEXES */
# define g_mutex_lock(mutex)						\
    G_THREAD_ECF (mutex_lock,    (void)0, (mutex), void)
# define g_mutex_trylock(mutex)						\
    G_THREAD_ECF (mutex_trylock, TRUE,    (mutex), gboolean)
# define g_mutex_unlock(mutex)						\
    G_THREAD_ECF (mutex_unlock,  (void)0, (mutex), void)
# define g_mutex_free(mutex)						\
    G_THREAD_ECF (mutex_free,    (void)0, (mutex), void)
# define g_cond_wait(cond, mutex)					\
    (g_thread_supported () ? ((void(*)(GCond*, GMutex*, gulong, gchar*))\
      g_thread_functions_for_glib_use.cond_wait)			\
        (cond, mutex, G_MUTEX_DEBUG_MAGIC, G_STRLOC) : (void) 0)
# define g_cond_timed_wait(cond, mutex, abs_time)			\
    (g_thread_supported () ?						\
      ((gboolean(*)(GCond*, GMutex*, GTimeVal*, gulong, gchar*))	\
        g_thread_functions_for_glib_use.cond_timed_wait)		\
          (cond, mutex, abs_time, G_MUTEX_DEBUG_MAGIC, G_STRLOC) : TRUE)
#endif /* G_ERRORCHECK_MUTEXES */

#define g_thread_supported()    (g_threads_got_initialized)
#define g_mutex_new()            G_THREAD_UF (mutex_new,      ())
#define g_cond_new()             G_THREAD_UF (cond_new,       ())
#define g_cond_signal(cond)      G_THREAD_CF (cond_signal,    (void)0, (cond))
#define g_cond_broadcast(cond)   G_THREAD_CF (cond_broadcast, (void)0, (cond))
#define g_cond_free(cond)        G_THREAD_CF (cond_free,      (void)0, (cond))
#define g_private_new(destructor) G_THREAD_UF (private_new, (destructor))
#define g_private_get(private_key) G_THREAD_CF (private_get, \
                                                ((gpointer)private_key), \
                                                (private_key))
#define g_private_set(private_key, value) G_THREAD_CF (private_set, \
                                                       (void) (private_key = \
                                                        (GPrivate*) (value)), \
                                                       (private_key, value))
#define g_thread_yield()              G_THREAD_CF (thread_yield, (void)0, ())
#define g_thread_exit()               G_THREAD_CF (thread_exit, (void)0, ())

GThread* g_thread_create (GThreadFunc            thread_func,
                          gpointer               arg,
                          gulong                 stack_size,
                          gboolean               joinable,
                          gboolean               bound,
                          GThreadPriority        priority,
                          GError               **error);
GThread* g_thread_self (void);
void g_thread_join (GThread *thread);
void g_thread_set_priority (GThread         *thread,
                            GThreadPriority  priority);

/* GStaticMutexes can be statically initialized with the value
 * G_STATIC_MUTEX_INIT, and then they can directly be used, that is
 * much easier, than having to explicitly allocate the mutex before
 * use
 */
#define g_static_mutex_lock(mutex) \
    g_mutex_lock (g_static_mutex_get_mutex (mutex))
#define g_static_mutex_trylock(mutex) \
    g_mutex_trylock (g_static_mutex_get_mutex (mutex))
#define g_static_mutex_unlock(mutex) \
    g_mutex_unlock (g_static_mutex_get_mutex (mutex))
void g_static_mutex_init (GStaticMutex *mutex);
void g_static_mutex_free (GStaticMutex *mutex);

struct _GStaticPrivate
{
  guint index;
};
#define G_STATIC_PRIVATE_INIT { 0 }
void     g_static_private_init           (GStaticPrivate   *private_key);
gpointer g_static_private_get            (GStaticPrivate   *private_key);
void     g_static_private_set            (GStaticPrivate   *private_key,
					  gpointer          data,
					  GDestroyNotify    notify);
void     g_static_private_free           (GStaticPrivate   *private_key);

typedef struct _GStaticRecMutex GStaticRecMutex;
struct _GStaticRecMutex
{
  GStaticMutex mutex;
  unsigned int depth;
  GSystemThread owner;
};

#define G_STATIC_REC_MUTEX_INIT { G_STATIC_MUTEX_INIT }
void     g_static_rec_mutex_init        (GStaticRecMutex *mutex);
void     g_static_rec_mutex_lock        (GStaticRecMutex *mutex);
gboolean g_static_rec_mutex_trylock     (GStaticRecMutex *mutex);
void     g_static_rec_mutex_unlock      (GStaticRecMutex *mutex);
void     g_static_rec_mutex_lock_full   (GStaticRecMutex *mutex,
                                         guint            depth);
guint    g_static_rec_mutex_unlock_full (GStaticRecMutex *mutex);
void     g_static_rec_mutex_free        (GStaticRecMutex *mutex);

typedef struct _GStaticRWLock GStaticRWLock;
struct _GStaticRWLock
{
  GStaticMutex mutex;
  GCond *read_cond;
  GCond *write_cond;
  guint read_counter;
  gboolean write;
  guint want_to_write;
};

#define G_STATIC_RW_LOCK_INIT { G_STATIC_MUTEX_INIT, NULL, NULL, 0, FALSE, FALSE }

void      g_static_rw_lock_init           (GStaticRWLock* lock);
void      g_static_rw_lock_reader_lock    (GStaticRWLock* lock);
gboolean  g_static_rw_lock_reader_trylock (GStaticRWLock* lock);
void      g_static_rw_lock_reader_unlock  (GStaticRWLock* lock);
void      g_static_rw_lock_writer_lock    (GStaticRWLock* lock);
gboolean  g_static_rw_lock_writer_trylock (GStaticRWLock* lock);
void      g_static_rw_lock_writer_unlock  (GStaticRWLock* lock);
void      g_static_rw_lock_free           (GStaticRWLock* lock);

/* these are some convenience macros that expand to nothing if GLib
 * was configured with --disable-threads. for using StaticMutexes,
 * you define them with G_LOCK_DEFINE_STATIC (name) or G_LOCK_DEFINE (name)
 * if you need to export the mutex. With G_LOCK_EXTERN (name) you can
 * declare such an globally defined lock. name is a unique identifier
 * for the protected varibale or code portion. locking, testing and
 * unlocking of such mutexes can be done with G_LOCK(), G_UNLOCK() and
 * G_TRYLOCK() respectively.
 */
extern void glib_dummy_decl (void);
#define G_LOCK_NAME(name)               g__ ## name ## _lock
#ifdef  G_THREADS_ENABLED
#  define G_LOCK_DEFINE_STATIC(name)    static G_LOCK_DEFINE (name)
#  define G_LOCK_DEFINE(name)           \
    GStaticMutex G_LOCK_NAME (name) = G_STATIC_MUTEX_INIT
#  define G_LOCK_EXTERN(name)           extern GStaticMutex G_LOCK_NAME (name)

#  ifdef G_DEBUG_LOCKS
#    define G_LOCK(name)                G_STMT_START{             \
        g_log (G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,                   \
               "file %s: line %d (%s): locking: %s ",             \
               __FILE__,        __LINE__, G_GNUC_PRETTY_FUNCTION, \
               #name);                                            \
        g_static_mutex_lock (&G_LOCK_NAME (name));                \
     }G_STMT_END
#    define G_UNLOCK(name)              G_STMT_START{             \
        g_log (G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,                   \
               "file %s: line %d (%s): unlocking: %s ",           \
               __FILE__,        __LINE__, G_GNUC_PRETTY_FUNCTION, \
               #name);                                            \
       g_static_mutex_unlock (&G_LOCK_NAME (name));               \
     }G_STMT_END
#    define G_TRYLOCK(name)                                       \
        (g_log (G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,                  \
               "file %s: line %d (%s): try locking: %s ",         \
               __FILE__,        __LINE__, G_GNUC_PRETTY_FUNCTION, \
               #name), g_static_mutex_trylock (&G_LOCK_NAME (name)))
#  else  /* !G_DEBUG_LOCKS */
#    define G_LOCK(name) g_static_mutex_lock       (&G_LOCK_NAME (name))
#    define G_UNLOCK(name) g_static_mutex_unlock   (&G_LOCK_NAME (name))
#    define G_TRYLOCK(name) g_static_mutex_trylock (&G_LOCK_NAME (name))
#  endif /* !G_DEBUG_LOCKS */
#else   /* !G_THREADS_ENABLED */
#  define G_LOCK_DEFINE_STATIC(name)    extern void glib_dummy_decl (void)
#  define G_LOCK_DEFINE(name)           extern void glib_dummy_decl (void)
#  define G_LOCK_EXTERN(name)           extern void glib_dummy_decl (void)
#  define G_LOCK(name)
#  define G_UNLOCK(name)
#  define G_TRYLOCK(name)               (TRUE)
#endif  /* !G_THREADS_ENABLED */

G_END_DECLS

#endif /* __G_THREAD_H__ */