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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: selbuf.c,v 1.4 2000/06/17 10:38:14 mdw Exp $ |
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4 | * |
5 | * Line-buffering select handler |
6 | * |
7 | * (c) 1999 Straylight/Edgeware |
8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of the mLib utilities library. |
13 | * |
14 | * mLib is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU Library General Public License as |
16 | * published by the Free Software Foundation; either version 2 of the |
17 | * License, or (at your option) any later version. |
18 | * |
19 | * mLib is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
22 | * GNU Library General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU Library General Public |
25 | * License along with mLib; if not, write to the Free |
26 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
27 | * MA 02111-1307, USA. |
28 | */ |
29 | |
30 | /*----- Revision history --------------------------------------------------* |
31 | * |
32 | * $Log: selbuf.c,v $ |
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33 | * Revision 1.4 2000/06/17 10:38:14 mdw |
34 | * Add support for variable buffer sizes. |
35 | * |
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36 | * Revision 1.3 1999/05/22 13:41:00 mdw |
37 | * Fix end-of-file detection and error handling. |
38 | * |
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39 | * Revision 1.2 1999/05/17 20:36:50 mdw |
40 | * Make the magical constants for the buffer flags uppercase. |
41 | * |
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42 | * Revision 1.1 1999/05/14 21:01:15 mdw |
43 | * Integrated `select' handling bits from the background resolver project. |
44 | * |
45 | */ |
46 | |
47 | /*----- Header files ------------------------------------------------------*/ |
48 | |
49 | #include <errno.h> |
50 | #include <stdio.h> |
51 | #include <stdlib.h> |
52 | #include <string.h> |
53 | |
54 | #include <sys/types.h> |
55 | #include <sys/time.h> |
56 | #include <unistd.h> |
57 | |
58 | #include "lbuf.h" |
59 | #include "sel.h" |
60 | #include "selbuf.h" |
61 | |
62 | /*----- Main code ---------------------------------------------------------*/ |
63 | |
64 | /* --- @selbuf_enable@ --- * |
65 | * |
66 | * Arguments: @selbuf *b@ = pointer to buffer block |
67 | * |
68 | * Returns: --- |
69 | * |
70 | * Use: Enables a buffer for reading, and emits any queued lines |
71 | * to the buffer's owner. |
72 | */ |
73 | |
74 | void selbuf_enable(selbuf *b) |
75 | { |
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76 | if (!(b->b.f & LBUF_ENABLE)) { |
77 | b->b.f |= LBUF_ENABLE; |
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78 | sel_addfile(&b->reader); |
79 | lbuf_flush(&b->b, 0, 0); |
80 | } |
81 | } |
82 | |
83 | /* --- @selbuf_disable@ --- * |
84 | * |
85 | * Arguments: @selbuf *b@ = pointer to a buffer block |
86 | * |
87 | * Returns: --- |
88 | * |
89 | * Use: Disables a buffer. It won't be read from until it's |
90 | * enabled again. |
91 | */ |
92 | |
93 | void selbuf_disable(selbuf *b) |
94 | { |
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95 | if (b->b.f & LBUF_ENABLE) { |
96 | b->b.f &= ~LBUF_ENABLE; |
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97 | sel_rmfile(&b->reader); |
98 | } |
99 | } |
100 | |
101 | /* --- @selbuf_read@ --- * |
102 | * |
103 | * Arguments: @int fd@ = file descriptor to read from |
104 | * @int mode@ = what we can do to the file |
105 | * @void *vp@ = pointer to buffer context |
106 | * |
107 | * Returns: --- |
108 | * |
109 | * Use: Acts on the result of a @select@ call. |
110 | */ |
111 | |
112 | static void selbuf_read(int fd, unsigned mode, void *vp) |
113 | { |
114 | selbuf *b = vp; |
115 | char *p; |
116 | size_t sz; |
117 | int n; |
118 | |
119 | sz = lbuf_free(&b->b, &p); |
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120 | n = read(fd, p, sz); |
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121 | if (n == 0) |
122 | lbuf_close(&b->b); |
123 | else if (n > 0) |
124 | lbuf_flush(&b->b, p, n); |
125 | else switch (errno) { |
126 | case EINTR: |
127 | case EAGAIN: |
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128 | #if EAGAIN != EWOULDBLOCK |
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129 | case EWOULDBLOCK: |
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130 | #endif |
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131 | return; |
132 | default: |
133 | lbuf_close(&b->b); |
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134 | } |
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135 | } |
136 | |
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137 | /* --- @selbuf_setsize@ --- * |
138 | * |
139 | * Arguments: @selbuf *b@ = pointer to buffer block |
140 | * @size_t sz@ = size of buffer |
141 | * |
142 | * Returns: --- |
143 | * |
144 | * Use: Sets the size of the buffer used for reading lines. |
145 | */ |
146 | |
147 | void selbuf_setsize(selbuf *b, size_t sz) |
148 | { |
149 | lbuf_setsize(&b->b, sz); |
150 | } |
151 | |
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152 | /* --- @selbuf_init@ --- * |
153 | * |
154 | * Arguments: @selbuf *b@ = pointer to buffer block |
155 | * @sel_state *s@ = pointer to select state to attach to |
156 | * @int fd@ = file descriptor to listen to |
157 | * @void (*func)(char *s, void *p)@ = function to call |
158 | * @void *p@ = argument for function |
159 | * |
160 | * Returns: --- |
161 | * |
162 | * Use: Initializes a buffer block. |
163 | */ |
164 | |
165 | void selbuf_init(selbuf *b, |
166 | sel_state *s, |
167 | int fd, |
168 | void (*func)(char */*s*/, void */*p*/), |
169 | void *p) |
170 | { |
171 | lbuf_init(&b->b, func, p); |
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172 | b->b.f &= ~LBUF_ENABLE; |
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173 | sel_initfile(s, &b->reader, fd, SEL_READ, selbuf_read, b); |
174 | selbuf_enable(b); |
175 | } |
176 | |
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177 | /* --- @selbuf_destroy@ --- * |
178 | * |
179 | * Arguments: @selbuf *b@ = pointer to buffer block |
180 | * |
181 | * Returns: --- |
182 | * |
183 | * Use: Deallocates a line buffer and frees any resources it owned. |
184 | */ |
185 | |
186 | void selbuf_destroy(selbuf *b) |
187 | { |
188 | selbuf_disable(b); |
189 | lbuf_destroy(&b->b); |
190 | } |
191 | |
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192 | /*----- That's all, folks -------------------------------------------------*/ |