2 * This file is part of DisOrder
3 * Copyright (C) 2008 Richard Kettlewell
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.
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.
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
21 /** @file lib/macros.c
22 * @brief Macro expansion
45 VECTOR_TYPE(mx_node_vector, const struct mx_node *, xrealloc);
47 /** @brief Definition of an expansion */
49 /** @brief Minimum permitted arguments */
52 /** @brief Maximum permitted arguments */
58 /** @brief Callback (cast to appropriate type) */
62 /** @brief Expansion takes parsed templates, not strings */
63 #define EXP_MAGIC 0x0001
65 static hash *expansions;
67 /* Parsing ------------------------------------------------------------------ */
69 /** @brief Parse a template
70 * @param filename Input filename (for diagnostics)
71 * @param line Line number (use 1 on initial call)
72 * @param input Start of text to parse
73 * @param end End of text to parse or NULL
74 * @return Pointer to parse tree root node
76 * Parses the text in [start, end) and returns an (immutable) parse
77 * tree representing it.
79 * If @p end is NULL then the whole string is parsed.
81 * Note that the @p filename value stored in the parse tree is @p filename,
82 * i.e. it is not copied.
84 const struct mx_node *mx_parse(const char *filename,
88 int braces, expansion_start_line, argument_start_line;
89 const char *argument_start, *argument_end, *p;
90 struct mx_node_vector v[1];
92 struct mx_node *head = 0, **tailp = &head, *e;
93 int omitted_terminator;
96 end = input + strlen(input);
99 expansion_start_line = line;
101 /* Gather up text without any expansions in. */
102 while(input < end && *input != '@') {
105 dynstr_append(d, *input++);
108 e = xmalloc(sizeof *e);
110 e->filename = filename;
111 e->line = expansion_start_line;
118 mx_node_vector_init(v);
122 expansion_start_line = line;
123 omitted_terminator = 0;
124 while(!omitted_terminator && input < end && *input != '@') {
125 /* Skip whitespace */
126 if(isspace((unsigned char)*input)) {
133 /* This is a bracketed argument. We'll walk over it counting
134 * braces to figure out where the end is. */
136 argument_start = input;
137 argument_start_line = line;
138 while(input < end && (*input != '}' || braces > 0)) {
140 case '{': ++braces; break;
141 case '}': --braces; break;
142 case '\n': ++line; break;
145 /* If we run out of input without seeing a '}' that's an error */
147 fatal(0, "%s:%d: unterminated expansion '%.*s'",
148 filename, argument_start_line,
149 (int)(input - argument_start), argument_start);
150 /* Consistency check */
151 assert(*input == '}');
152 /* Record the end of the argument */
153 argument_end = input;
154 /* Step over the '}' */
156 if(input < end && isspace((unsigned char)*input)) {
157 /* There is at least some whitespace after the '}'. Look
158 * ahead and see what is after all the whitespace. */
159 for(p = input; p < end && isspace((unsigned char)*p); ++p)
161 /* Now we are looking after the whitespace. If it's
162 * anything other than '{', including the end of the input,
163 * then we infer that this expansion finished at the '}' we
164 * just saw. (NB that we don't move input forward to p -
165 * the whitespace is NOT part of the expansion.) */
166 if(p == end || *p != '{')
167 omitted_terminator = 1;
170 /* We are looking at an unbracketed argument. (A common example would
171 * be the expansion or macro name.) This is terminated by an '@'
172 * (indicating the end of the expansion), a ':' (allowing a subsequent
173 * unbracketed argument) or a '{' (allowing a bracketed argument). The
174 * end of the input will also do. */
175 argument_start = input;
176 argument_start_line = line;
178 && *input != '@' && *input != '{' && *input != ':') {
179 if(*input == '\n') ++line;
182 argument_end = input;
183 /* Trailing whitespace is not significant in unquoted arguments (and
184 * leading whitespace is eliminated by the whitespace skip above). */
185 while(argument_end > argument_start
186 && isspace((unsigned char)argument_end[-1]))
188 /* Step over the ':' if that's what we see */
189 if(input < end && *input == ':')
192 /* Now we have an argument in [argument_start, argument_end), and we know
193 * its filename and initial line number. This is sufficient to parse
195 mx_node_vector_append(v, mx_parse(filename, argument_start_line,
196 argument_start, argument_end));
198 /* We're at the end of an expansion. We might have hit the end of the
199 * input, we might have hit an '@' or we might have matched the
200 * omitted_terminator criteria. */
202 if(!omitted_terminator) {
203 assert(*input == '@');
207 /* @@ terminates this file */
210 /* Currently we require that the first element, the expansion name, is
211 * always plain text. Removing this restriction would raise some
212 * interesting possibilities but for the time being it is considered an
214 if(v->vec[0]->type != MX_TEXT)
215 fatal(0, "%s:%d: expansion names may not themselves contain expansions",
216 v->vec[0]->filename, v->vec[0]->line);
217 /* Guarantee a NULL terminator (for the case where there's more than one
219 mx_node_vector_terminate(v);
220 e = xmalloc(sizeof *e);
222 e->filename = filename;
223 e->line = expansion_start_line;
224 e->type = MX_EXPANSION;
225 e->name = v->vec[0]->text;
226 e->nargs = v->nvec - 1;
227 e->args = v->nvec > 1 ? &v->vec[1] : 0;
234 static void mx__dump(struct dynstr *d, const struct mx_node *m) {
241 dynstr_append_string(d, m->text);
244 dynstr_append(d, '@');
245 dynstr_append_string(d, m->name);
246 for(n = 0; n < m->nargs; ++n) {
247 dynstr_append(d, '{');
248 mx__dump(d, m->args[n]);
249 dynstr_append(d, '}');
251 dynstr_append(d, '@');
254 assert(!"invalid m->type");
256 mx__dump(d, m->next);
259 /** @brief Dump a parse macro expansion to a string */
260 char *mx_dump(const struct mx_node *m) {
269 /* Expansion registration --------------------------------------------------- */
271 static void mx__register(unsigned flags,
275 void (*callback)()) {
276 struct expansion e[1];
279 expansions = hash_new(sizeof(struct expansion));
283 e->callback = callback;
284 hash_add(expansions, name, &e, HASH_INSERT_OR_REPLACE);
287 /** @brief Register a simple expansion rule
289 * @param min Minimum number of arguments
290 * @param max Maximum number of arguments
291 * @param callback Callback to write output
293 void mx_register(const char *name,
296 mx_simple_callback *callback) {
297 mx__register(0, name, min, max, (void (*)())callback);
300 /** @brief Register a magic expansion rule
302 * @param min Minimum number of arguments
303 * @param max Maximum number of arguments
304 * @param callback Callback to write output
306 void mx_magic_register(const char *name,
309 mx_magic_callback *callback) {
310 mx__register(EXP_MAGIC, name, min, max, (void (*)())callback);
313 /* Expansion ---------------------------------------------------------------- */
315 /** @brief Expand a template
316 * @param m Where to start
317 * @param output Where to send output
319 * @return 0 on success, non-0 on error∑
321 * If a sink write fails then -1 is returned. If any callback returns non-zero
322 * then that value is returned. It is suggested that callbacks adopt this
323 * policy too and use positive values to mean other kinds of fatal error.
325 int mx_expand(const struct mx_node *m,
328 const struct expansion *e;
335 if(sink_writes(output, m->text) < 0)
339 if(!(e = hash_find(expansions, m->name))) {
340 error(0, "%s:%d: unknown expansion name '%s'",
341 m->filename, m->line, m->name);
342 if(sink_printf(output, "[[%s unknown]]", m->name) < 0)
344 } else if(m->nargs < e->min) {
345 error(0, "%s:%d: expansion '%s' requires %d args, only %d given",
346 m->filename, m->line, m->name, e->min, m->nargs);
347 if(sink_printf(output, "[[%s too few args]]", m->name) < 0)
349 } else if(m->nargs > e->max) {
350 error(0, "%s:%d: expansion '%s' takes at most %d args, but %d given",
351 m->filename, m->line, m->name, e->max, m->nargs);
352 if(sink_printf(output, "[[%s too many args]]", m->name) < 0)
354 } else if(e->flags & EXP_MAGIC) {
355 /* Magic callbacks we can call directly */
356 if((rc = ((mx_magic_callback *)e->callback)(m->nargs,
362 /* For simple callbacks we expand their arguments for them */
363 char **args = xcalloc(1 + m->nargs, sizeof (char *));
366 for(n = 0; n < m->nargs; ++n)
367 if((rc = mx_expandstr(m->args[n], &args[n], u)))
370 if((rc = ((mx_simple_callback *)e->callback)(m->nargs,
378 assert(!"invalid m->type");
380 return mx_expand(m, output, u);
383 /** @brief Expand a template storing the result in a string
384 * @param m Where to start
385 * @param sp Where to store string
387 * @return 0 on success, non-0 on error
389 * Same return conventions as mx_expand(). This wrapper is slightly more
390 * convenient to use from 'magic' expansions.
392 int mx_expandstr(const struct mx_node *m,
398 if(!(rc = mx_expand(m, sink_dynstr(d), u))) {
405 /** @brief Expand a template file
406 * @param path Filename
407 * @param output Where to send output
409 * @return 0 on success, non-0 on error
411 * Same return conventions as mx_expand().
413 int mx_expand_file(const char *path,
421 if((fd = open(path, O_RDONLY)) < 0)
422 fatal(errno, "error opening %s", path);
423 if(fstat(fd, &sb) < 0)
424 fatal(errno, "error statting %s", path);
425 if(!S_ISREG(sb.st_mode))
426 fatal(0, "%s: not a regular file", path);
428 b = xmalloc_noptr(sb.st_size);
429 while(sofar < sb.st_size) {
430 n = read(fd, b + sofar, sb.st_size - sofar);
434 fatal(0, "unexpected EOF reading %s", path);
435 else if(errno != EINTR)
436 fatal(errno, "error reading %s", path);
439 return mx_expand(mx_parse(path, 1, b, b + sb.st_size),