chiark / gitweb /
Expansion syntax rewrite. Not documented yet, but then nor was the
[disorder] / lib / macros-builtin.c
CommitLineData
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1/*
2 * This file is part of DisOrder
3 * Copyright (C) 2008 Richard Kettlewell
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
18 * USA
19 */
20
21/** @file lib/macros-builtin.c
22 * @brief Built-in expansions
23 *
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24 * This is a grab-bag of non-domain-specific expansions. Documentation will be
25 * generated from the comments at the head of each function.
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26 */
27
28#include <config.h>
29#include "types.h"
30
31#include <stdio.h>
32#include <string.h>
33#include <errno.h>
34#include <assert.h>
35#include <unistd.h>
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36#include <fcntl.h>
37#include <sys/stat.h>
f640bcb3 38
9faa7a88 39#include "hash.h"
b36be3a1 40#include "mem.h"
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41#include "macros.h"
42#include "sink.h"
43#include "syscalls.h"
44#include "log.h"
45#include "wstat.h"
46#include "kvp.h"
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47#include "split.h"
48#include "printf.h"
49#include "vector.h"
50
51static struct vector include_path;
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52
53/** @brief Return 1 if @p s is 'true' else 0 */
54int mx_str2bool(const char *s) {
55 return !strcmp(s, "true");
56}
57
58/** @brief Return "true" if @p n is nonzero else "false" */
59const char *mx_bool2str(int n) {
60 return n ? "true" : "false";
61}
62
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63/** @brief Write a boolean result */
64static int mx_bool_result(struct sink *output, int result) {
65 if(sink_writes(output, mx_bool2str(result)) < 0)
66 return -1;
67 else
68 return 0;
69}
70
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71/** @brief Search the include path */
72char *mx_find(const char *name) {
73 char *path;
74 int n;
75
76 if(name[0] == '/') {
77 if(access(name, O_RDONLY) < 0) {
78 error(errno, "cannot read %s", name);
79 return 0;
80 }
81 path = xstrdup(name);
82 } else {
83 /* Search the include path */
84 for(n = 0; n < include_path.nvec; ++n) {
85 byte_xasprintf(&path, "%s/%s", include_path.vec[n], name);
86 if(access(path, O_RDONLY) == 0)
87 break;
88 }
89 if(n >= include_path.nvec) {
90 error(0, "cannot find '%s' in search path", name);
91 return 0;
92 }
93 }
94 return path;
95}
96
97/* @include{TEMPLATE}@
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98 *
99 * Includes TEMPLATE.
100 *
101 * TEMPLATE can be an absolute filename starting with a '/'; only the file with
102 * exactly this name will be included.
103 *
104 * Alternatively it can be a relative filename, not starting with a '/'. In
105 * this case the file will be searched for in the include path. When searching
106 * paths, unreadable files are treated as if they do not exist (rather than
107 * matching then producing an error).
f640bcb3 108 *
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109 * If the name chosen ends ".tmpl" then the file will be expanded as a
110 * template. Anything else is included byte-for-byte without further
111 * modification.
112 *
113 * Only regular files are allowed (no devices, sockets or name pipes).
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114 */
115static int exp_include(int attribute((unused)) nargs,
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116 char **args,
117 struct sink *output,
118 void *u) {
9faa7a88 119 const char *path;
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120 int fd, n;
121 char buffer[4096];
122 struct stat sb;
b36be3a1 123
9faa7a88 124 if(!(path = mx_find(args[0]))) {
f5fdc06f 125 if(sink_printf(output, "[[cannot find '%s']]", args[0]) < 0)
dd0f422a 126 return 0;
9faa7a88 127 return 0;
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128 }
129 /* If it's a template expand it */
130 if(strlen(path) >= 5 && !strncmp(path + strlen(path) - 5, ".tmpl", 5))
131 return mx_expand_file(path, output, u);
132 /* Read the raw file. As with mx_expand_file() we insist that the file is a
133 * regular file. */
134 if((fd = open(path, O_RDONLY)) < 0)
135 fatal(errno, "error opening %s", path);
136 if(fstat(fd, &sb) < 0)
137 fatal(errno, "error statting %s", path);
138 if(!S_ISREG(sb.st_mode))
139 fatal(0, "%s: not a regular file", path);
140 while((n = read(fd, buffer, sizeof buffer)) > 0) {
141 if(sink_write(output, buffer, n) < 0) {
142 xclose(fd);
143 return -1;
144 }
145 }
146 if(n < 0)
147 fatal(errno, "error reading %s", path);
148 xclose(fd);
149 return 0;
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150}
151
9faa7a88 152/* @include{COMMAND}@
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153 *
154 * Executes COMMAND via the shell (using "sh -c") and copies its
155 * standard output to the template output. The shell command output
156 * is not expanded or modified in any other way.
157 *
158 * The shell command's standard error is copied to the error log.
159 *
160 * If the shell exits nonzero then this is reported to the error log
161 * but otherwise no special action is taken.
162 */
163static int exp_shell(int attribute((unused)) nargs,
164 char **args,
165 struct sink *output,
166 void attribute((unused)) *u) {
167 int w, p[2], n;
168 char buffer[4096];
169 pid_t pid;
170
171 xpipe(p);
172 if(!(pid = xfork())) {
173 exitfn = _exit;
174 xclose(p[0]);
175 xdup2(p[1], 1);
176 xclose(p[1]);
177 execlp("sh", "sh", "-c", args[0], (char *)0);
178 fatal(errno, "error executing sh");
179 }
180 xclose(p[1]);
181 while((n = read(p[0], buffer, sizeof buffer))) {
182 if(n < 0) {
183 if(errno == EINTR)
184 continue;
185 else
186 fatal(errno, "error reading from pipe");
187 }
188 if(output->write(output, buffer, n) < 0)
189 return -1;
190 }
191 xclose(p[0]);
192 while((n = waitpid(pid, &w, 0)) < 0 && errno == EINTR)
193 ;
194 if(n < 0)
195 fatal(errno, "error calling waitpid");
196 if(w)
197 error(0, "shell command '%s' %s", args[0], wstat(w));
198 return 0;
199}
200
9faa7a88 201/* @if{CONDITION}{IF-TRUE}{IF-FALSE}@
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202 *
203 * If CONDITION is "true" then evaluates to IF-TRUE. Otherwise
204 * evaluates to IF-FALSE. The IF-FALSE part is optional.
205 */
206static int exp_if(int nargs,
207 const struct mx_node **args,
208 struct sink *output,
209 void *u) {
210 char *s;
211 int rc;
212
b36be3a1 213 if((rc = mx_expandstr(args[0], &s, u, "argument #0 (CONDITION)")))
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214 return rc;
215 if(mx_str2bool(s))
216 return mx_expand(args[1], output, u);
217 else if(nargs > 2)
218 return mx_expand(args[2], output, u);
219 else
220 return 0;
221}
222
9faa7a88 223/* @and{BRANCH}{BRANCH}...@
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224 *
225 * Expands to "true" if all the branches are "true" otherwise to "false". If
226 * there are no brances then the result is "true". Only as many branches as
227 * necessary to compute the answer are evaluated (starting from the first one),
228 * so if later branches have side effects they may not take place.
229 */
230static int exp_and(int nargs,
231 const struct mx_node **args,
232 struct sink *output,
233 void *u) {
234 int n, result = 1, rc;
b36be3a1 235 char *s, *argname;
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236
237 for(n = 0; n < nargs; ++n) {
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238 byte_xasprintf(&argname, "argument #%d", n);
239 if((rc = mx_expandstr(args[n], &s, u, argname)))
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240 return rc;
241 if(!mx_str2bool(s)) {
242 result = 0;
243 break;
244 }
245 }
b36be3a1 246 return mx_bool_result(output, result);
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247}
248
9faa7a88 249/* @or{BRANCH}{BRANCH}...@
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250 *
251 * Expands to "true" if any of the branches are "true" otherwise to "false".
252 * If there are no brances then the result is "false". Only as many branches
253 * as necessary to compute the answer are evaluated (starting from the first
254 * one), so if later branches have side effects they may not take place.
255 */
256static int exp_or(int nargs,
257 const struct mx_node **args,
258 struct sink *output,
259 void *u) {
260 int n, result = 0, rc;
b36be3a1 261 char *s, *argname;
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262
263 for(n = 0; n < nargs; ++n) {
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264 byte_xasprintf(&argname, "argument #%d", n);
265 if((rc = mx_expandstr(args[n], &s, u, argname)))
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266 return rc;
267 if(mx_str2bool(s)) {
268 result = 1;
269 break;
270 }
271 }
b36be3a1 272 return mx_bool_result(output, result);
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273}
274
9faa7a88 275/* @not{CONDITION}@
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276 *
277 * Expands to "true" unless CONDITION is "true" in which case "false".
278 */
279static int exp_not(int attribute((unused)) nargs,
280 char **args,
281 struct sink *output,
282 void attribute((unused)) *u) {
b36be3a1 283 return mx_bool_result(output, !mx_str2bool(args[0]));
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284}
285
9faa7a88 286/* @#{...}@
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287 *
288 * Expands to nothing. The argument(s) are not fully evaluated, and no side
289 * effects occur.
290 */
291static int exp_comment(int attribute((unused)) nargs,
292 const struct mx_node attribute((unused)) **args,
293 struct sink attribute((unused)) *output,
294 void attribute((unused)) *u) {
295 return 0;
296}
297
9faa7a88 298/* @urlquote{STRING}@
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299 *
300 * URL-quotes a string, i.e. replaces any characters not safe to use unquoted
301 * in a URL with %-encoded form.
302 */
303static int exp_urlquote(int attribute((unused)) nargs,
304 char **args,
305 struct sink *output,
306 void attribute((unused)) *u) {
307 if(sink_writes(output, urlencodestring(args[0])) < 0)
308 return -1;
309 else
310 return 0;
311}
312
9faa7a88 313/* @eq{S1}{S2}...@
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314 *
315 * Expands to "true" if all the arguments are identical, otherwise to "false"
316 * (i.e. if any pair of arguments differs).
317 *
318 * If there are no arguments then expands to "true". Evaluates all arguments
319 * (with their side effects) even if that's not strictly necessary to discover
320 * the result.
321 */
322static int exp_eq(int nargs,
323 char **args,
324 struct sink *output,
325 void attribute((unused)) *u) {
326 int n, result = 1;
327
328 for(n = 1; n < nargs; ++n) {
329 if(strcmp(args[n], args[0])) {
330 result = 0;
331 break;
332 }
333 }
334 return mx_bool_result(output, result);
335}
336
9faa7a88 337/* @ne{S1}{S2}...@
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338 *
339 * Expands to "true" if all of the arguments differ from one another, otherwise
340 * to "false" (i.e. if any value appears more than once).
341 *
342 * If there are no arguments then expands to "true". Evaluates all arguments
343 * (with their side effects) even if that's not strictly necessary to discover
344 * the result.
345 */
346static int exp_ne(int nargs,
347 char **args,
348 struct sink *output,
349 void attribute((unused))*u) {
350 hash *h = hash_new(sizeof (char *));
351 int n, result = 1;
352
353 for(n = 0; n < nargs; ++n)
354 if(hash_add(h, args[n], "", HASH_INSERT)) {
355 result = 0;
356 break;
357 }
358 return mx_bool_result(output, result);
359}
360
9faa7a88 361/* @discard{...}@
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362 *
363 * Expands to nothing. Unlike the comment expansion @#{...}, side effects of
364 * arguments are not suppressed. So this can be used to surround a collection
365 * of macro definitions with whitespace, free text commentary, etc.
366 */
367static int exp_discard(int attribute((unused)) nargs,
368 char attribute((unused)) **args,
369 struct sink attribute((unused)) *output,
370 void attribute((unused)) *u) {
371 return 0;
372}
373
9faa7a88 374/* @define{NAME}{ARG1 ARG2...}{DEFINITION}@
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375 *
376 * Define a macro. The macro will be called NAME and will act like an
377 * expansion. When it is expanded, the expansion is replaced by DEFINITION,
378 * with each occurence of @ARG1@ etc replaced by the parameters to the
379 * expansion.
380 */
381static int exp_define(int attribute((unused)) nargs,
382 const struct mx_node **args,
383 struct sink attribute((unused)) *output,
384 void attribute((unused)) *u) {
385 char **as, *name, *argnames;
386 int rc, nas;
387
388 if((rc = mx_expandstr(args[0], &name, u, "argument #0 (NAME)")))
389 return rc;
390 if((rc = mx_expandstr(args[1], &argnames, u, "argument #1 (ARGS)")))
391 return rc;
392 as = split(argnames, &nas, 0, 0, 0);
393 mx_register_macro(name, nas, as, args[2]);
394 return 0;
395}
396
dd0f422a 397/** @brief Register built-in expansions */
f640bcb3 398void mx_register_builtin(void) {
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399 mx_register_magic("#", 0, INT_MAX, exp_comment);
400 mx_register_magic("and", 0, INT_MAX, exp_and);
401 mx_register_magic("define", 3, 3, exp_define);
402 mx_register_magic("if", 2, 3, exp_if);
403 mx_register_magic("or", 0, INT_MAX, exp_or);
404 mx_register("discard", 0, INT_MAX, exp_discard);
405 mx_register("eq", 0, INT_MAX, exp_eq);
f640bcb3 406 mx_register("include", 1, 1, exp_include);
b36be3a1 407 mx_register("ne", 0, INT_MAX, exp_ne);
f640bcb3 408 mx_register("not", 1, 1, exp_not);
b36be3a1 409 mx_register("shell", 1, 1, exp_shell);
f640bcb3 410 mx_register("urlquote", 1, 1, exp_urlquote);
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411}
412
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413/** @brief Add a directory to the search path
414 * @param s Directory to add
415 */
416void mx_search_path(const char *s) {
417 vector_append(&include_path, xstrdup(s));
418}
419
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420/*
421Local Variables:
422c-basic-offset:2
423comment-column:40
424fill-column:79
425indent-tabs-mode:nil
426End:
427*/