include/glib-compat.h

   1 /*
   2  * GLIB Compatibility Functions
   3  *
   4  * Copyright IBM, Corp. 2013
   5  *
   6  * Authors:
   7  *  Anthony Liguori   <aliguori@us.ibm.com>
   8  *  Michael Tokarev   <mjt@tls.msk.ru>
   9  *  Paolo Bonzini     <pbonzini@redhat.com>
  10  *
  11  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  12  * See the COPYING file in the top-level directory.
  13  *
  14  */
  15
  16 #ifndef QEMU_GLIB_COMPAT_H
  17 #define QEMU_GLIB_COMPAT_H
  18
  19 #include <glib.h>
  20
  21 /* GLIB version compatibility flags */
  22 #if !GLIB_CHECK_VERSION(2, 26, 0)
  23 #define G_TIME_SPAN_SECOND              (G_GINT64_CONSTANT(1000000))
  24 #endif
  25
  26 #if !GLIB_CHECK_VERSION(2, 28, 0)
  27 static inline gint64 qemu_g_get_monotonic_time(void)
  28 {
  29     /* g_get_monotonic_time() is best-effort so we can use the wall clock as a
  30      * fallback.
  31      */
  32
  33     GTimeVal time;
  34     g_get_current_time(&time);
  35
  36     return time.tv_sec * G_TIME_SPAN_SECOND + time.tv_usec;
  37 }
  38 /* work around distro backports of this interface */
  39 #define g_get_monotonic_time() qemu_g_get_monotonic_time()
  40 #endif
  41
  42 #ifdef _WIN32
  43 /*
  44  * g_poll has a problem on Windows when using
  45  * timeouts < 10ms, so use wrapper.
  46  */
  47 #define g_poll(fds, nfds, timeout) g_poll_fixed(fds, nfds, timeout)
  48 gint g_poll_fixed(GPollFD *fds, guint nfds, gint timeout);
  49 #endif
  50
  51 #if !GLIB_CHECK_VERSION(2, 31, 0)
  52 /* before glib-2.31, GMutex and GCond was dynamic-only (there was a separate
  53  * GStaticMutex, but it didn't work with condition variables).
  54  *
  55  * Our implementation uses GOnce to fake a static implementation that does
  56  * not require separate initialization.
  57  * We need to rename the types to avoid passing our CompatGMutex/CompatGCond
  58  * by mistake to a function that expects GMutex/GCond.  However, for ease
  59  * of use we keep the GLib function names.  GLib uses macros for the
  60  * implementation, we use inline functions instead and undefine the macros.
  61  */
  62
  63 typedef struct CompatGMutex {
  64     GOnce once;
  65 } CompatGMutex;
  66
  67 typedef struct CompatGCond {
  68     GOnce once;
  69 } CompatGCond;
  70
  71 static inline gpointer do_g_mutex_new(gpointer unused)
  72 {
  73     return (gpointer) g_mutex_new();
  74 }
  75
  76 static inline void g_mutex_init(CompatGMutex *mutex)
  77 {
  78     mutex->once = (GOnce) G_ONCE_INIT;
  79 }
  80
  81 static inline void g_mutex_clear(CompatGMutex *mutex)
  82 {
  83     g_assert(mutex->once.status != G_ONCE_STATUS_PROGRESS);
  84     if (mutex->once.retval) {
  85         g_mutex_free((GMutex *) mutex->once.retval);
  86     }
  87     mutex->once = (GOnce) G_ONCE_INIT;
  88 }
  89
  90 static inline void (g_mutex_lock)(CompatGMutex *mutex)
  91 {
  92     g_once(&mutex->once, do_g_mutex_new, NULL);
  93     g_mutex_lock((GMutex *) mutex->once.retval);
  94 }
  95 #undef g_mutex_lock
  96
  97 static inline gboolean (g_mutex_trylock)(CompatGMutex *mutex)
  98 {
  99     g_once(&mutex->once, do_g_mutex_new, NULL);
 100     return g_mutex_trylock((GMutex *) mutex->once.retval);
 101 }
 102 #undef g_mutex_trylock
 103
 104
 105 static inline void (g_mutex_unlock)(CompatGMutex *mutex)
 106 {
 107     g_mutex_unlock((GMutex *) mutex->once.retval);
 108 }
 109 #undef g_mutex_unlock
 110
 111 static inline gpointer do_g_cond_new(gpointer unused)
 112 {
 113     return (gpointer) g_cond_new();
 114 }
 115
 116 static inline void g_cond_init(CompatGCond *cond)
 117 {
 118     cond->once = (GOnce) G_ONCE_INIT;
 119 }
 120
 121 static inline void g_cond_clear(CompatGCond *cond)
 122 {
 123     g_assert(cond->once.status != G_ONCE_STATUS_PROGRESS);
 124     if (cond->once.retval) {
 125         g_cond_free((GCond *) cond->once.retval);
 126     }
 127     cond->once = (GOnce) G_ONCE_INIT;
 128 }
 129
 130 static inline void (g_cond_wait)(CompatGCond *cond, CompatGMutex *mutex)
 131 {
 132     g_assert(mutex->once.status != G_ONCE_STATUS_PROGRESS);
 133     g_once(&cond->once, do_g_cond_new, NULL);
 134     g_cond_wait((GCond *) cond->once.retval, (GMutex *) mutex->once.retval);
 135 }
 136 #undef g_cond_wait
 137
 138 static inline void (g_cond_broadcast)(CompatGCond *cond)
 139 {
 140     g_once(&cond->once, do_g_cond_new, NULL);
 141     g_cond_broadcast((GCond *) cond->once.retval);
 142 }
 143 #undef g_cond_broadcast
 144
 145 static inline void (g_cond_signal)(CompatGCond *cond)
 146 {
 147     g_once(&cond->once, do_g_cond_new, NULL);
 148     g_cond_signal((GCond *) cond->once.retval);
 149 }
 150 #undef g_cond_signal
 151
 152
 153 /* before 2.31 there was no g_thread_new() */
 154 static inline GThread *g_thread_new(const char *name,
 155                                     GThreadFunc func, gpointer data)
 156 {
 157     GThread *thread = g_thread_create(func, data, TRUE, NULL);
 158     if (!thread) {
 159         g_error("creating thread");
 160     }
 161     return thread;
 162 }
 163 #else
 164 #define CompatGMutex GMutex
 165 #define CompatGCond GCond
 166 #endif /* glib 2.31 */
 167
 168 #endif