mdw@git.distorted.org.uk Git - mLib/blob - sel/selbuf.c

   1 /* -*-c-*-
   2  *
   3  * Line-buffering select handler
   4  *
   5  * (c) 1999 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of the mLib utilities library.
  11  *
  12  * mLib is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU Library General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * mLib is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU Library General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Library General Public
  23  * License along with mLib; if not, write to the Free
  24  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  25  * MA 02111-1307, USA.
  26  */
  27
  28 /*----- Header files ------------------------------------------------------*/
  29
  30 #include <errno.h>
  31 #include <stdio.h>
  32 #include <stdlib.h>
  33 #include <string.h>
  34
  35 #include <sys/types.h>
  36 #include <sys/time.h>
  37 #include <unistd.h>
  38
  39 #include "lbuf.h"
  40 #include "sel.h"
  41 #include "selbuf.h"
  42
  43 /*----- Main code ---------------------------------------------------------*/
  44
  45 /* --- @selbuf_enable@ --- *
  46  *
  47  * Arguments:   @selbuf *b@ = pointer to buffer block
  48  *
  49  * Returns:     ---
  50  *
  51  * Use:         Enables a buffer for reading, and emits any queued lines
  52  *              to the buffer's owner.
  53  */
  54
  55 void selbuf_enable(selbuf *b)
  56 {
  57   if (!(b->b.f & LBUF_ENABLE)) {
  58     b->b.f |= LBUF_ENABLE;
  59     sel_addfile(&b->reader);
  60     lbuf_flush(&b->b, 0, 0);
  61   }
  62 }
  63
  64 /* --- @selbuf_disable@ --- *
  65  *
  66  * Arguments:   @selbuf *b@ = pointer to a buffer block
  67  *
  68  * Returns:     ---
  69  *
  70  * Use:         Disables a buffer.  It won't be read from until it's
  71  *              enabled again.
  72  */
  73
  74 void selbuf_disable(selbuf *b)
  75 {
  76   if (b->b.f & LBUF_ENABLE) {
  77     b->b.f &= ~LBUF_ENABLE;
  78     sel_rmfile(&b->reader);
  79   }
  80 }
  81
  82 /* --- @selbuf_read@ --- *
  83  *
  84  * Arguments:   @int fd@ = file descriptor to read from
  85  *              @int mode@ = what we can do to the file
  86  *              @void *vp@ = pointer to buffer context
  87  *
  88  * Returns:     ---
  89  *
  90  * Use:         Acts on the result of a @select@ call.
  91  */
  92
  93 static void selbuf_read(int fd, unsigned mode, void *vp)
  94 {
  95   selbuf *b = vp;
  96   char *p;
  97   size_t sz;
  98   int n;
  99
 100   sz = lbuf_free(&b->b, &p);
 101   n = read(fd, p, sz);
 102   if (n == 0)
 103     lbuf_close(&b->b);
 104   else if (n > 0)
 105     lbuf_flush(&b->b, p, n);
 106   else switch (errno) {
 107     case EINTR:
 108     case EAGAIN:
 109 #if EAGAIN != EWOULDBLOCK
 110     case EWOULDBLOCK:
 111 #endif
 112       return;
 113     default:
 114       lbuf_close(&b->b);
 115   }
 116 }
 117
 118 /* --- @selbuf_setsize@ --- *
 119  *
 120  * Arguments:   @selbuf *b@ = pointer to buffer block
 121  *              @size_t sz@ = size of buffer
 122  *
 123  * Returns:     ---
 124  *
 125  * Use:         Sets the size of the buffer used for reading lines.
 126  */
 127
 128 void selbuf_setsize(selbuf *b, size_t sz)
 129 {
 130   lbuf_setsize(&b->b, sz);
 131 }
 132
 133 /* --- @selbuf_init@ --- *
 134  *
 135  * Arguments:   @selbuf *b@ = pointer to buffer block
 136  *              @sel_state *s@ = pointer to select state to attach to
 137  *              @int fd@ = file descriptor to listen to
 138  *              @lbuf_func *func@ = function to call
 139  *              @void *p@ = argument for function
 140  *
 141  * Returns:     ---
 142  *
 143  * Use:         Initializes a buffer block.
 144  */
 145
 146 void selbuf_init(selbuf *b, sel_state *s, int fd, lbuf_func *func, void *p)
 147 {
 148   lbuf_init(&b->b, func, p);
 149   b->b.f &= ~LBUF_ENABLE;
 150   sel_initfile(s, &b->reader, fd, SEL_READ, selbuf_read, b);
 151   selbuf_enable(b);
 152 }
 153
 154 /* --- @selbuf_destroy@ --- *
 155  *
 156  * Arguments:   @selbuf *b@ = pointer to buffer block
 157  *
 158  * Returns:     ---
 159  *
 160  * Use:         Deallocates a line buffer and frees any resources it owned.
 161  */
 162
 163 void selbuf_destroy(selbuf *b)
 164 {
 165   selbuf_disable(b);
 166   lbuf_destroy(&b->b);
 167 }
 168
 169 /*----- That's all, folks -------------------------------------------------*/