Home | History | Annotate | Line # | Download | only in src 
      1 /* Copyright libuv project contributors. All rights reserved.
      2  *
      3  * Permission is hereby granted, free of charge, to any person obtaining a copy
      4  * of this software and associated documentation files (the "Software"), to
      5  * deal in the Software without restriction, including without limitation the
      6  * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
      7  * sell copies of the Software, and to permit persons to whom the Software is
      8  * furnished to do so, subject to the following conditions:
      9  *
     10  * The above copyright notice and this permission notice shall be included in
     11  * all copies or substantial portions of the Software.
     12  *
     13  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     14  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     15  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
     16  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
     17  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
     18  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
     19  * IN THE SOFTWARE.
     20  */
     21 
     22 #include "uv.h"
     23 #include "uv-common.h"
     24 
     25 #include <stdlib.h>
     26 #ifndef _WIN32
     27 #include <pthread.h>
     28 #endif
     29 
     30 #if defined(PTHREAD_BARRIER_SERIAL_THREAD)
     31 STATIC_ASSERT(sizeof(uv_barrier_t) == sizeof(pthread_barrier_t));
     32 #endif
     33 
     34 /* Note: guard clauses should match uv_barrier_t's in include/uv/unix.h. */
     35 #if defined(_AIX) || \
     36     defined(__OpenBSD__) || \
     37     !defined(PTHREAD_BARRIER_SERIAL_THREAD)
     38 int uv_barrier_init(uv_barrier_t* barrier, unsigned int count) {
     39   int rc;
     40 #ifdef _WIN32
     41   uv_barrier_t* b;
     42   b = barrier;
     43 
     44   if (barrier == NULL || count == 0)
     45     return UV_EINVAL;
     46 #else
     47   struct _uv_barrier* b;
     48 
     49   if (barrier == NULL || count == 0)
     50     return UV_EINVAL;
     51 
     52   b = uv__malloc(sizeof(*b));
     53   if (b == NULL)
     54     return UV_ENOMEM;
     55 #endif
     56 
     57   b->in = 0;
     58   b->out = 0;
     59   b->threshold = count;
     60 
     61   rc = uv_mutex_init(&b->mutex);
     62   if (rc != 0)
     63     goto error2;
     64 
     65   /* TODO(vjnash): remove these uv_cond_t casts in v2. */
     66   rc = uv_cond_init((uv_cond_t*) &b->cond);
     67   if (rc != 0)
     68     goto error;
     69 
     70 #ifndef _WIN32
     71   barrier->b = b;
     72 #endif
     73   return 0;
     74 
     75 error:
     76   uv_mutex_destroy(&b->mutex);
     77 error2:
     78 #ifndef _WIN32
     79   uv__free(b);
     80 #endif
     81   return rc;
     82 }
     83 
     84 
     85 int uv_barrier_wait(uv_barrier_t* barrier) {
     86   int last;
     87 #ifdef _WIN32
     88   uv_barrier_t* b;
     89   b = barrier;
     90 #else
     91   struct _uv_barrier* b;
     92 
     93   if (barrier == NULL || barrier->b == NULL)
     94     return UV_EINVAL;
     95 
     96   b = barrier->b;
     97 #endif
     98 
     99   uv_mutex_lock(&b->mutex);
    100 
    101   while (b->out != 0)
    102     uv_cond_wait((uv_cond_t*) &b->cond, &b->mutex);
    103 
    104   if (++b->in == b->threshold) {
    105     b->in = 0;
    106     b->out = b->threshold;
    107     uv_cond_broadcast((uv_cond_t*) &b->cond);
    108   } else {
    109     do
    110       uv_cond_wait((uv_cond_t*) &b->cond, &b->mutex);
    111     while (b->in != 0);
    112   }
    113 
    114   last = (--b->out == 0);
    115   if (last)
    116     uv_cond_broadcast((uv_cond_t*) &b->cond);
    117 
    118   uv_mutex_unlock(&b->mutex);
    119   return last;
    120 }
    121 
    122 
    123 void uv_barrier_destroy(uv_barrier_t* barrier) {
    124 #ifdef _WIN32
    125   uv_barrier_t* b;
    126   b = barrier;
    127 #else
    128   struct _uv_barrier* b;
    129   b = barrier->b;
    130 #endif
    131 
    132   uv_mutex_lock(&b->mutex);
    133 
    134   assert(b->in == 0);
    135   while (b->out != 0)
    136     uv_cond_wait((uv_cond_t*) &b->cond, &b->mutex);
    137 
    138   if (b->in != 0)
    139     abort();
    140 
    141   uv_mutex_unlock(&b->mutex);
    142   uv_mutex_destroy(&b->mutex);
    143   uv_cond_destroy((uv_cond_t*) &b->cond);
    144 
    145 #ifndef  _WIN32
    146   uv__free(barrier->b);
    147   barrier->b = NULL;
    148 #endif
    149 }
    150 
    151 #else
    152 
    153 int uv_barrier_init(uv_barrier_t* barrier, unsigned int count) {
    154   return UV__ERR(pthread_barrier_init(barrier, NULL, count));
    155 }
    156 
    157 
    158 int uv_barrier_wait(uv_barrier_t* barrier) {
    159   int rc;
    160 
    161   rc = pthread_barrier_wait(barrier);
    162   if (rc != 0)
    163     if (rc != PTHREAD_BARRIER_SERIAL_THREAD)
    164       abort();
    165 
    166   return rc == PTHREAD_BARRIER_SERIAL_THREAD;
    167 }
    168 
    169 
    170 void uv_barrier_destroy(uv_barrier_t* barrier) {
    171   if (pthread_barrier_destroy(barrier))
    172     abort();
    173 }
    174 
    175 #endif
    176