| 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.c |
| 22 | * @brief Macro expansion |
| 23 | */ |
| 24 | |
| 25 | #include "common.h" |
| 26 | |
| 27 | #include <ctype.h> |
| 28 | #include <sys/stat.h> |
| 29 | #include <fcntl.h> |
| 30 | #include <unistd.h> |
| 31 | #include <errno.h> |
| 32 | |
| 33 | #include "hash.h" |
| 34 | #include "macros.h" |
| 35 | #include "mem.h" |
| 36 | #include "vector.h" |
| 37 | #include "log.h" |
| 38 | #include "sink.h" |
| 39 | #include "syscalls.h" |
| 40 | #include "printf.h" |
| 41 | |
| 42 | VECTOR_TYPE(mx_node_vector, const struct mx_node *, xrealloc); |
| 43 | |
| 44 | /** @brief Definition of an expansion */ |
| 45 | struct expansion { |
| 46 | /** @brief Minimum permitted arguments */ |
| 47 | int min; |
| 48 | |
| 49 | /** @brief Maximum permitted arguments */ |
| 50 | int max; |
| 51 | |
| 52 | /** @brief Flags |
| 53 | * |
| 54 | * See: |
| 55 | * - @ref EXP_SIMPLE |
| 56 | * - @ref EXP_MAGIC |
| 57 | * - @ref EXP_MACRO |
| 58 | * - @ref EXP_TYPE_MASK |
| 59 | */ |
| 60 | unsigned flags; |
| 61 | |
| 62 | /** @brief Macro argument names */ |
| 63 | char **args; |
| 64 | |
| 65 | /** @brief Callback (cast to appropriate type) |
| 66 | * |
| 67 | * Cast to @ref mx_simple_callback or @ref mx_magic_callback as required. */ |
| 68 | void (*callback)(); |
| 69 | |
| 70 | /** @brief Macro definition |
| 71 | * |
| 72 | * Only for @ref EXP_MACRO expansions. */ |
| 73 | const struct mx_node *definition; |
| 74 | }; |
| 75 | |
| 76 | /** @brief Expansion takes pre-expanded strings |
| 77 | * |
| 78 | * @p callback is cast to @ref mx_simple_callback. */ |
| 79 | #define EXP_SIMPLE 0x0000 |
| 80 | |
| 81 | /** @brief Expansion takes parsed templates, not strings |
| 82 | * |
| 83 | * @p callback is cast to @ref mx_magic_callback. The callback must do its own |
| 84 | * expansion e.g. via mx_expandstr() where necessary. */ |
| 85 | #define EXP_MAGIC 0x0001 |
| 86 | |
| 87 | /** @brief Expansion is a macro */ |
| 88 | #define EXP_MACRO 0x0002 |
| 89 | |
| 90 | /** @brief Mask of types */ |
| 91 | #define EXP_TYPE_MASK 0x0003 |
| 92 | |
| 93 | /** @brief Hash of all expansions |
| 94 | * |
| 95 | * Created by mx_register(), mx_register_macro() or mx_register_magic(). |
| 96 | */ |
| 97 | static hash *expansions; |
| 98 | |
| 99 | static int mx__expand_macro(const struct expansion *e, |
| 100 | const struct mx_node *m, |
| 101 | struct sink *output, |
| 102 | void *u); |
| 103 | |
| 104 | /* Parsing ------------------------------------------------------------------ */ |
| 105 | |
| 106 | static int next_non_whitespace(const char *input, |
| 107 | const char *end) { |
| 108 | while(input < end && isspace((unsigned char)*input)) |
| 109 | ++input; |
| 110 | return input < end ? *input : -1; |
| 111 | } |
| 112 | |
| 113 | /** @brief Parse a template |
| 114 | * @param filename Input filename (for diagnostics) |
| 115 | * @param line Line number (use 1 on initial call) |
| 116 | * @param input Start of text to parse |
| 117 | * @param end End of text to parse or NULL |
| 118 | * @return Pointer to parse tree root node |
| 119 | * |
| 120 | * Parses the text in [start, end) and returns an (immutable) parse |
| 121 | * tree representing it. |
| 122 | * |
| 123 | * If @p end is NULL then the whole string is parsed. |
| 124 | * |
| 125 | * Note that the @p filename value stored in the parse tree is @p filename, |
| 126 | * i.e. it is not copied. |
| 127 | */ |
| 128 | const struct mx_node *mx_parse(const char *filename, |
| 129 | int line, |
| 130 | const char *input, |
| 131 | const char *end) { |
| 132 | int braces, argument_start_line, obracket, cbracket; |
| 133 | const char *argument_start, *argument_end; |
| 134 | struct mx_node_vector v[1]; |
| 135 | struct dynstr d[1]; |
| 136 | struct mx_node *head = 0, **tailp = &head, *e; |
| 137 | |
| 138 | if(!end) |
| 139 | end = input + strlen(input); |
| 140 | while(input < end) { |
| 141 | if(*input != '@') { |
| 142 | e = xmalloc(sizeof *e); |
| 143 | e->next = 0; |
| 144 | e->filename = filename; |
| 145 | e->line = line; |
| 146 | e->type = MX_TEXT; |
| 147 | dynstr_init(d); |
| 148 | /* Gather up text without any expansions in. */ |
| 149 | while(input < end && *input != '@') { |
| 150 | if(*input == '\n') |
| 151 | ++line; |
| 152 | dynstr_append(d, *input++); |
| 153 | } |
| 154 | dynstr_terminate(d); |
| 155 | e->text = d->vec; |
| 156 | *tailp = e; |
| 157 | tailp = &e->next; |
| 158 | continue; |
| 159 | } |
| 160 | if(input + 1 < end) |
| 161 | switch(input[1]) { |
| 162 | case '@': |
| 163 | /* '@@' expands to '@' */ |
| 164 | e = xmalloc(sizeof *e); |
| 165 | e->next = 0; |
| 166 | e->filename = filename; |
| 167 | e->line = line; |
| 168 | e->type = MX_TEXT; |
| 169 | e->text = "@"; |
| 170 | *tailp = e; |
| 171 | tailp = &e->next; |
| 172 | input += 2; |
| 173 | continue; |
| 174 | case '#': |
| 175 | /* '@#' starts a (newline-eating comment), like dnl */ |
| 176 | input += 2; |
| 177 | while(input < end && *input != '\n') |
| 178 | ++input; |
| 179 | if(*input == '\n') { |
| 180 | ++line; |
| 181 | ++input; |
| 182 | } |
| 183 | continue; |
| 184 | case '_': |
| 185 | /* '@_' expands to nothing. It's there to allow dump to terminate |
| 186 | * expansions without having to know what follows. */ |
| 187 | input += 2; |
| 188 | continue; |
| 189 | } |
| 190 | /* It's a full expansion */ |
| 191 | ++input; |
| 192 | e = xmalloc(sizeof *e); |
| 193 | e->next = 0; |
| 194 | e->filename = filename; |
| 195 | e->line = line; |
| 196 | e->type = MX_EXPANSION; |
| 197 | /* Collect the expansion name. Expansion names start with an alnum and |
| 198 | * consist of alnums and '-'. We don't permit whitespace between the '@' |
| 199 | * and the name. */ |
| 200 | dynstr_init(d); |
| 201 | if(input == end) |
| 202 | fatal(0, "%s:%d: invalid expansion syntax (truncated)", |
| 203 | filename, e->line); |
| 204 | if(!isalnum((unsigned char)*input)) |
| 205 | fatal(0, "%s:%d: invalid expansion syntax (unexpected %#x)", |
| 206 | filename, e->line, (unsigned char)*input); |
| 207 | while(input < end && (isalnum((unsigned char)*input) || *input == '-')) |
| 208 | dynstr_append(d, *input++); |
| 209 | dynstr_terminate(d); |
| 210 | e->name = d->vec; |
| 211 | /* See what the bracket character is */ |
| 212 | obracket = next_non_whitespace(input, end); |
| 213 | switch(obracket) { |
| 214 | case '(': cbracket = ')'; break; |
| 215 | case '[': cbracket = ']'; break; |
| 216 | case '{': cbracket = '}'; break; |
| 217 | default: cbracket = obracket = -1; break; /* no arguments */ |
| 218 | } |
| 219 | mx_node_vector_init(v); |
| 220 | if(obracket >= 0) { |
| 221 | /* Gather up arguments */ |
| 222 | while(next_non_whitespace(input, end) == obracket) { |
| 223 | while(isspace((unsigned char)*input)) { |
| 224 | if(*input == '\n') |
| 225 | ++line; |
| 226 | ++input; |
| 227 | } |
| 228 | ++input; /* the bracket */ |
| 229 | braces = 0; |
| 230 | /* Find the end of the argument */ |
| 231 | argument_start = input; |
| 232 | argument_start_line = line; |
| 233 | while(input < end && (*input != cbracket || braces > 0)) { |
| 234 | const int c = *input++; |
| 235 | |
| 236 | if(c == obracket) |
| 237 | ++braces; |
| 238 | else if(c == cbracket) |
| 239 | --braces; |
| 240 | else if(c == '\n') |
| 241 | ++line; |
| 242 | } |
| 243 | if(input >= end) { |
| 244 | /* We ran out of input without encountering a balanced cbracket */ |
| 245 | fatal(0, "%s:%d: unterminated expansion argument '%.*s'", |
| 246 | filename, argument_start_line, |
| 247 | (int)(input - argument_start), argument_start); |
| 248 | } |
| 249 | /* Consistency check */ |
| 250 | assert(*input == cbracket); |
| 251 | /* Record the end of the argument */ |
| 252 | argument_end = input; |
| 253 | /* Step over the cbracket */ |
| 254 | ++input; |
| 255 | /* Now we have an argument in [argument_start, argument_end), and we |
| 256 | * know its filename and initial line number. This is sufficient to |
| 257 | * parse it. */ |
| 258 | mx_node_vector_append(v, mx_parse(filename, argument_start_line, |
| 259 | argument_start, argument_end)); |
| 260 | } |
| 261 | } |
| 262 | /* Guarantee a NULL terminator (for the case where there's more than one |
| 263 | * argument) */ |
| 264 | mx_node_vector_terminate(v); |
| 265 | /* Fill in the remains of the node */ |
| 266 | e->nargs = v->nvec; |
| 267 | e->args = v->vec; |
| 268 | *tailp = e; |
| 269 | tailp = &e->next; |
| 270 | } |
| 271 | return head; |
| 272 | } |
| 273 | |
| 274 | static void mx__dump(struct dynstr *d, const struct mx_node *m) { |
| 275 | int n; |
| 276 | const struct mx_node *mm; |
| 277 | |
| 278 | if(!m) |
| 279 | return; |
| 280 | switch(m->type) { |
| 281 | case MX_TEXT: |
| 282 | if(m->text[0] == '@') |
| 283 | dynstr_append(d, '@'); |
| 284 | dynstr_append_string(d, m->text); |
| 285 | break; |
| 286 | case MX_EXPANSION: |
| 287 | dynstr_append(d, '@'); |
| 288 | dynstr_append_string(d, m->name); |
| 289 | for(n = 0; n < m->nargs; ++n) { |
| 290 | dynstr_append(d, '{'); |
| 291 | mx__dump(d, m->args[n]); |
| 292 | dynstr_append(d, '}'); |
| 293 | } |
| 294 | /* If the next non-whitespace is '{', add @_ to stop it being |
| 295 | * misinterpreted */ |
| 296 | mm = m->next; |
| 297 | while(mm && mm->type == MX_TEXT) { |
| 298 | switch(next_non_whitespace(mm->text, mm->text + strlen(mm->text))) { |
| 299 | case -1: |
| 300 | mm = mm->next; |
| 301 | continue; |
| 302 | case '{': |
| 303 | dynstr_append_string(d, "@_"); |
| 304 | break; |
| 305 | default: |
| 306 | break; |
| 307 | } |
| 308 | break; |
| 309 | } |
| 310 | break; |
| 311 | default: |
| 312 | assert(!"invalid m->type"); |
| 313 | } |
| 314 | mx__dump(d, m->next); |
| 315 | } |
| 316 | |
| 317 | /** @brief Dump a parse macro expansion to a string |
| 318 | * |
| 319 | * Not of production quality! Only intended for testing! |
| 320 | */ |
| 321 | char *mx_dump(const struct mx_node *m) { |
| 322 | struct dynstr d[1]; |
| 323 | |
| 324 | dynstr_init(d); |
| 325 | mx__dump(d, m); |
| 326 | dynstr_terminate(d); |
| 327 | return d->vec; |
| 328 | } |
| 329 | |
| 330 | /* Expansion registration --------------------------------------------------- */ |
| 331 | |
| 332 | static int mx__register(unsigned flags, |
| 333 | const char *name, |
| 334 | int min, |
| 335 | int max, |
| 336 | char **args, |
| 337 | void (*callback)(), |
| 338 | const struct mx_node *definition) { |
| 339 | struct expansion e[1]; |
| 340 | |
| 341 | if(!expansions) |
| 342 | expansions = hash_new(sizeof(struct expansion)); |
| 343 | e->min = min; |
| 344 | e->max = max; |
| 345 | e->flags = flags; |
| 346 | e->args = args; |
| 347 | e->callback = callback; |
| 348 | e->definition = definition; |
| 349 | return hash_add(expansions, name, &e, HASH_INSERT_OR_REPLACE); |
| 350 | } |
| 351 | |
| 352 | /** @brief Register a simple expansion rule |
| 353 | * @param name Name |
| 354 | * @param min Minimum number of arguments |
| 355 | * @param max Maximum number of arguments |
| 356 | * @param callback Callback to write output |
| 357 | */ |
| 358 | void mx_register(const char *name, |
| 359 | int min, |
| 360 | int max, |
| 361 | mx_simple_callback *callback) { |
| 362 | mx__register(EXP_SIMPLE, name, min, max, 0, (void (*)())callback, 0); |
| 363 | } |
| 364 | |
| 365 | /** @brief Register a magic expansion rule |
| 366 | * @param name Name |
| 367 | * @param min Minimum number of arguments |
| 368 | * @param max Maximum number of arguments |
| 369 | * @param callback Callback to write output |
| 370 | */ |
| 371 | void mx_register_magic(const char *name, |
| 372 | int min, |
| 373 | int max, |
| 374 | mx_magic_callback *callback) { |
| 375 | mx__register(EXP_MAGIC, name, min, max, 0, (void (*)())callback, 0); |
| 376 | } |
| 377 | |
| 378 | /** @brief Register a macro |
| 379 | * @param name Name |
| 380 | * @param nargs Number of arguments |
| 381 | * @param args Argument names |
| 382 | * @param definition Macro definition |
| 383 | * @return 0 on success, negative on error |
| 384 | */ |
| 385 | int mx_register_macro(const char *name, |
| 386 | int nargs, |
| 387 | char **args, |
| 388 | const struct mx_node *definition) { |
| 389 | if(mx__register(EXP_MACRO, name, nargs, nargs, args, 0/*callback*/, |
| 390 | definition)) { |
| 391 | #if 0 |
| 392 | /* This locates the error to the definition, which may be a line or two |
| 393 | * beyond the @define command itself. The backtrace generated by |
| 394 | * mx_expand() may help more. */ |
| 395 | error(0, "%s:%d: duplicate definition of '%s'", |
| 396 | definition->filename, definition->line, name); |
| 397 | #endif |
| 398 | return -2; |
| 399 | } |
| 400 | return 0; |
| 401 | } |
| 402 | |
| 403 | /* Expansion ---------------------------------------------------------------- */ |
| 404 | |
| 405 | /** @brief Expand a template |
| 406 | * @param m Where to start |
| 407 | * @param output Where to send output |
| 408 | * @param u User data |
| 409 | * @return 0 on success, non-0 on error |
| 410 | * |
| 411 | * Interpretation of return values: |
| 412 | * - 0 means success |
| 413 | * - -1 means an error writing to the sink. |
| 414 | * - other negative values mean errors generated from with the macro |
| 415 | * expansion system |
| 416 | * - positive values are reserved for the application |
| 417 | * |
| 418 | * If any callback returns non-zero then that value is returned, abandoning |
| 419 | * further expansion. |
| 420 | */ |
| 421 | int mx_expand(const struct mx_node *m, |
| 422 | struct sink *output, |
| 423 | void *u) { |
| 424 | const struct expansion *e; |
| 425 | int rc; |
| 426 | |
| 427 | if(!m) |
| 428 | return 0; |
| 429 | switch(m->type) { |
| 430 | case MX_TEXT: |
| 431 | if(sink_writes(output, m->text) < 0) |
| 432 | return -1; |
| 433 | break; |
| 434 | case MX_EXPANSION: |
| 435 | rc = 0; |
| 436 | if(!(e = hash_find(expansions, m->name))) { |
| 437 | error(0, "%s:%d: unknown expansion name '%s'", |
| 438 | m->filename, m->line, m->name); |
| 439 | if(sink_printf(output, "[['%s' unknown]]", m->name) < 0) |
| 440 | return -1; |
| 441 | } else if(m->nargs < e->min) { |
| 442 | error(0, "%s:%d: expansion '%s' requires %d args, only %d given", |
| 443 | m->filename, m->line, m->name, e->min, m->nargs); |
| 444 | if(sink_printf(output, "[['%s' too few args]]", m->name) < 0) |
| 445 | return -1; |
| 446 | } else if(m->nargs > e->max) { |
| 447 | error(0, "%s:%d: expansion '%s' takes at most %d args, but %d given", |
| 448 | m->filename, m->line, m->name, e->max, m->nargs); |
| 449 | if(sink_printf(output, "[['%s' too many args]]", m->name) < 0) |
| 450 | return -1; |
| 451 | } else switch(e->flags & EXP_TYPE_MASK) { |
| 452 | case EXP_MAGIC: { |
| 453 | /* Magic callbacks we can call directly */ |
| 454 | rc = ((mx_magic_callback *)e->callback)(m->nargs, |
| 455 | m->args, |
| 456 | output, |
| 457 | u); |
| 458 | break; |
| 459 | } |
| 460 | case EXP_SIMPLE: { |
| 461 | /* For simple callbacks we expand their arguments for them. */ |
| 462 | char **args = xcalloc(1 + m->nargs, sizeof (char *)), *argname; |
| 463 | int n; |
| 464 | |
| 465 | for(n = 0; n < m->nargs; ++n) { |
| 466 | /* Argument numbers are at least clear from looking at the text; |
| 467 | * adding names as well would be nice. TODO */ |
| 468 | byte_xasprintf(&argname, "argument #%d", n); |
| 469 | if((rc = mx_expandstr(m->args[n], &args[n], u, argname))) |
| 470 | break; |
| 471 | } |
| 472 | if(!rc) { |
| 473 | args[n] = NULL; |
| 474 | rc = ((mx_simple_callback *)e->callback)(m->nargs, |
| 475 | args, |
| 476 | output, |
| 477 | u); |
| 478 | } |
| 479 | break; |
| 480 | } |
| 481 | case EXP_MACRO: { |
| 482 | /* Macros we expand by rewriting their definition with argument values |
| 483 | * substituted and then expanding that. */ |
| 484 | rc = mx__expand_macro(e, m, output, u); |
| 485 | break; |
| 486 | } |
| 487 | default: |
| 488 | assert(!"impossible EXP_TYPE_MASK value"); |
| 489 | } |
| 490 | if(rc) { |
| 491 | /* For non-IO errors we generate some backtrace */ |
| 492 | if(rc != -1) |
| 493 | error(0, " ...in @%s at %s:%d", |
| 494 | m->name, m->filename, m->line); |
| 495 | return rc; |
| 496 | } |
| 497 | break; |
| 498 | default: |
| 499 | assert(!"invalid m->type"); |
| 500 | } |
| 501 | return mx_expand(m->next, output, u); |
| 502 | } |
| 503 | |
| 504 | /** @brief Expand a template storing the result in a string |
| 505 | * @param m Where to start |
| 506 | * @param sp Where to store string |
| 507 | * @param u User data |
| 508 | * @param what Token for backtrace, or NULL |
| 509 | * @return 0 on success, non-0 on error |
| 510 | * |
| 511 | * Same return conventions as mx_expand(). This wrapper is slightly more |
| 512 | * convenient to use from 'magic' expansions. |
| 513 | */ |
| 514 | int mx_expandstr(const struct mx_node *m, |
| 515 | char **sp, |
| 516 | void *u, |
| 517 | const char *what) { |
| 518 | struct dynstr d[1]; |
| 519 | int rc; |
| 520 | |
| 521 | dynstr_init(d); |
| 522 | if(!(rc = mx_expand(m, sink_dynstr(d), u))) { |
| 523 | dynstr_terminate(d); |
| 524 | *sp = d->vec; |
| 525 | } else |
| 526 | *sp = 0; |
| 527 | if(rc && rc != -1 && what) |
| 528 | error(0, " ...in %s at %s:%d", what, m->filename, m->line); |
| 529 | return rc; |
| 530 | } |
| 531 | |
| 532 | /** @brief Expand a template file |
| 533 | * @param path Filename |
| 534 | * @param output Where to send output |
| 535 | * @param u User data |
| 536 | * @return 0 on success, non-0 on error |
| 537 | * |
| 538 | * Same return conventions as mx_expand(). |
| 539 | */ |
| 540 | int mx_expand_file(const char *path, |
| 541 | struct sink *output, |
| 542 | void *u) { |
| 543 | int fd, n, rc; |
| 544 | struct stat sb; |
| 545 | char *b; |
| 546 | off_t sofar; |
| 547 | const struct mx_node *m; |
| 548 | |
| 549 | if((fd = open(path, O_RDONLY)) < 0) |
| 550 | fatal(errno, "error opening %s", path); |
| 551 | if(fstat(fd, &sb) < 0) |
| 552 | fatal(errno, "error statting %s", path); |
| 553 | if(!S_ISREG(sb.st_mode)) |
| 554 | fatal(0, "%s: not a regular file", path); |
| 555 | sofar = 0; |
| 556 | b = xmalloc_noptr(sb.st_size); |
| 557 | while(sofar < sb.st_size) { |
| 558 | n = read(fd, b + sofar, sb.st_size - sofar); |
| 559 | if(n > 0) |
| 560 | sofar += n; |
| 561 | else if(n == 0) |
| 562 | fatal(0, "unexpected EOF reading %s", path); |
| 563 | else if(errno != EINTR) |
| 564 | fatal(errno, "error reading %s", path); |
| 565 | } |
| 566 | xclose(fd); |
| 567 | m = mx_parse(path, 1, b, b + sb.st_size); |
| 568 | rc = mx_expand(m, output, u); |
| 569 | if(rc && rc != -1) |
| 570 | /* Mention inclusion in backtrace */ |
| 571 | error(0, " ...in inclusion of file '%s'", path); |
| 572 | return rc; |
| 573 | } |
| 574 | |
| 575 | /* Macros ------------------------------------------------------------------- */ |
| 576 | |
| 577 | /** @brief Rewrite a parse tree substituting sub-expansions |
| 578 | * @param m Parse tree to rewrite (from macro definition) |
| 579 | * @param ... Name/value pairs to rewrite |
| 580 | * @return Rewritten parse tree |
| 581 | * |
| 582 | * The name/value pair list consists of pairs of strings and is terminated by |
| 583 | * (char *)0. Names and values are both copied so need not survive the call. |
| 584 | */ |
| 585 | const struct mx_node *mx_rewritel(const struct mx_node *m, |
| 586 | ...) { |
| 587 | va_list ap; |
| 588 | hash *h = hash_new(sizeof (struct mx_node *)); |
| 589 | const char *n, *v; |
| 590 | struct mx_node *e; |
| 591 | |
| 592 | va_start(ap, m); |
| 593 | while((n = va_arg(ap, const char *))) { |
| 594 | v = va_arg(ap, const char *); |
| 595 | e = xmalloc(sizeof *e); |
| 596 | e->next = 0; |
| 597 | e->filename = m->filename; |
| 598 | e->line = m->line; |
| 599 | e->type = MX_TEXT; |
| 600 | e->text = xstrdup(v); |
| 601 | hash_add(h, n, &e, HASH_INSERT); |
| 602 | /* hash_add() copies n */ |
| 603 | } |
| 604 | return mx_rewrite(m, h); |
| 605 | } |
| 606 | |
| 607 | /** @brief Rewrite a parse tree substituting in macro arguments |
| 608 | * @param definition Parse tree to rewrite (from macro definition) |
| 609 | * @param h Hash mapping argument names to argument values |
| 610 | * @return Rewritten parse tree |
| 611 | */ |
| 612 | const struct mx_node *mx_rewrite(const struct mx_node *definition, |
| 613 | hash *h) { |
| 614 | const struct mx_node *head = 0, **tailp = &head, *argvalue, *m, *mm, **ap; |
| 615 | struct mx_node *nm; |
| 616 | int n; |
| 617 | |
| 618 | for(m = definition; m; m = m->next) { |
| 619 | switch(m->type) { |
| 620 | case MX_TEXT: |
| 621 | nm = xmalloc(sizeof *nm); |
| 622 | *nm = *m; /* Dumb copy of text node fields */ |
| 623 | nm->next = 0; /* Maintain list structure */ |
| 624 | *tailp = nm; |
| 625 | tailp = (const struct mx_node **)&nm->next; |
| 626 | break; |
| 627 | case MX_EXPANSION: |
| 628 | if(m->nargs == 0 |
| 629 | && (ap = hash_find(h, m->name))) { |
| 630 | /* This expansion has no arguments and its name matches one of the |
| 631 | * macro arguments. (Even if it's a valid expansion name we override |
| 632 | * it.) We insert its value at this point. We do NOT recursively |
| 633 | * rewrite the argument's value - it is outside the lexical scope of |
| 634 | * the argument name. |
| 635 | * |
| 636 | * We need to recreate the list structure but a shallow copy will |
| 637 | * suffice here. |
| 638 | */ |
| 639 | argvalue = *ap; |
| 640 | for(mm = argvalue; mm; mm = mm->next) { |
| 641 | nm = xmalloc(sizeof *nm); |
| 642 | *nm = *mm; |
| 643 | nm->next = 0; |
| 644 | *tailp = nm; |
| 645 | tailp = (const struct mx_node **)&nm->next; |
| 646 | } |
| 647 | } else { |
| 648 | /* This is some other expansion. We recursively rewrite its argument |
| 649 | * values according to h. */ |
| 650 | nm = xmalloc(sizeof *nm); |
| 651 | *nm = *m; |
| 652 | nm->args = xcalloc(nm->nargs, sizeof (struct mx_node *)); |
| 653 | for(n = 0; n < nm->nargs; ++n) |
| 654 | nm->args[n] = mx_rewrite(m->args[n], h); |
| 655 | nm->next = 0; |
| 656 | *tailp = nm; |
| 657 | tailp = (const struct mx_node **)&nm->next; |
| 658 | } |
| 659 | break; |
| 660 | default: |
| 661 | assert(!"invalid m->type"); |
| 662 | } |
| 663 | } |
| 664 | *tailp = 0; /* Mark end of list */ |
| 665 | return head; |
| 666 | } |
| 667 | |
| 668 | /** @brief Expand a macro |
| 669 | * @param e Macro definition |
| 670 | * @param m Macro expansion |
| 671 | * @param output Where to send output |
| 672 | * @param u User data |
| 673 | * @return 0 on success, non-0 on error |
| 674 | */ |
| 675 | static int mx__expand_macro(const struct expansion *e, |
| 676 | const struct mx_node *m, |
| 677 | struct sink *output, |
| 678 | void *u) { |
| 679 | hash *h = hash_new(sizeof (struct mx_node *)); |
| 680 | int n; |
| 681 | |
| 682 | /* We store the macro arguments in a hash. Currently there is no check for |
| 683 | * duplicate argument names (and this would be the wrong place for it |
| 684 | * anyway); if you do that you just lose in some undefined way. */ |
| 685 | for(n = 0; n < m->nargs; ++n) |
| 686 | hash_add(h, e->args[n], &m->args[n], HASH_INSERT); |
| 687 | /* Generate a rewritten parse tree */ |
| 688 | m = mx_rewrite(e->definition, h); |
| 689 | /* Expand the result */ |
| 690 | return mx_expand(m, output, u); |
| 691 | /* mx_expand() will update the backtrace */ |
| 692 | } |
| 693 | |
| 694 | /* |
| 695 | Local Variables: |
| 696 | c-basic-offset:2 |
| 697 | comment-column:40 |
| 698 | fill-column:79 |
| 699 | indent-tabs-mode:nil |
| 700 | End: |
| 701 | */ |