release/src/router/nginx/src/os/unix/ngx_aio_read_chain.c

   1
   2 /*
   3  * Copyright (C) Igor Sysoev
   4  * Copyright (C) Nginx, Inc.
   5  */
   6
   7
   8 #include <ngx_config.h>
   9 #include <ngx_core.h>
  10 #include <ngx_event.h>
  11
  12
  13 ssize_t
  14 ngx_aio_read_chain(ngx_connection_t *c, ngx_chain_t *cl)
  15 {
  16     int           n;
  17     u_char       *buf, *prev;
  18     size_t        size;
  19     ssize_t       total;
  20
  21     if (c->read->pending_eof) {
  22         c->read->ready = 0;
  23         return 0;
  24     }
  25
  26     total = 0;
  27
  28     while (cl) {
  29
  30         /* we can post the single aio operation only */
  31
  32         if (!c->read->ready) {
  33             return total ? total : NGX_AGAIN;
  34         }
  35
  36         buf = cl->buf->last;
  37         prev = cl->buf->last;
  38         size = 0;
  39
  40         /* coalesce the neighbouring bufs */
  41
  42         while (cl && prev == cl->buf->last) {
  43             size += cl->buf->end - cl->buf->last;
  44             prev = cl->buf->end;
  45             cl = cl->next;
  46         }
  47
  48         n = ngx_aio_read(c, buf, size);
  49
  50         ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "aio_read: %d", n);
  51
  52         if (n == NGX_AGAIN) {
  53             return total ? total : NGX_AGAIN;
  54         }
  55
  56         if (n == NGX_ERROR) {
  57             return NGX_ERROR;
  58         }
  59
  60         if (n == 0) {
  61             c->read->pending_eof = 1;
  62             if (total) {
  63                 c->read->eof = 0;
  64                 c->read->ready = 1;
  65             }
  66             return total;
  67         }
  68
  69         if (n > 0) {
  70             total += n;
  71         }
  72
  73         ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0,
  74                        "aio_read total: %d", total);
  75     }
  76
  77     return total ? total : NGX_AGAIN;
  78 }