cmd_cnd.c

   1 /*@ S-nail - a mail user agent derived from Berkeley Mail.
   2  *@ Commands: conditional constructs.
   3  *
   4  * Copyright (c) 2014 - 2015 Steffen (Daode) Nurpmeso <sdaoden@users.sf.net>.
   5  *
   6  * Permission to use, copy, modify, and/or distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18 #undef n_FILE
  19 #define n_FILE cmd_cnd
  20
  21 #ifndef HAVE_AMALGAMATION
  22 # include "nail.h"
  23 #endif
  24
  25 struct cond_stack {
  26    struct cond_stack *c_outer;
  27    bool_t            c_error; /* Bad expression, skip entire if..endif */
  28    bool_t            c_noop;  /* Outer stack !c_go, entirely no-op */
  29    bool_t            c_go;    /* Green light */
  30    bool_t            c_else;  /* In `else' clause */
  31    ui8_t             __dummy[4];
  32 };
  33
  34 struct if_cmd {
  35    char const  * const *ic_argv_base;
  36    char const  * const *ic_argv_max;
  37    char const  * const *ic_argv;
  38 };
  39
  40 static struct cond_stack   *_cond_stack;
  41
  42 /* */
  43 static void    _if_error(struct if_cmd const *icp, char const *msg_or_null,
  44                   char const *nearby_or_null);
  45
  46 /* noop and (1) don't work for real, only syntax-check and
  47  * (2) non-error return is ignored */
  48 static si8_t   _if_test(struct if_cmd *icp, bool_t noop);
  49 static si8_t   _if_group(struct if_cmd *icp, size_t level, bool_t noop);
  50
  51 static void
  52 _if_error(struct if_cmd const *icp, char const *msg_or_null,
  53    char const *nearby_or_null)
  54 {
  55    struct str s;
  56    NYD2_ENTER;
  57
  58    if (msg_or_null == NULL)
  59       msg_or_null = _("invalid expression syntax");
  60
  61    if (nearby_or_null != NULL)
  62       fprintf(stderr, _("`if' conditional: %s -- near \"%s\"\n"),
  63          msg_or_null, nearby_or_null);
  64    else
  65       fprintf(stderr, _("`if' conditional: %s\n"), msg_or_null);
  66
  67    if (options & (OPT_INTERACTIVE | OPT_D_V)) {
  68       str_concat_cpa(&s, icp->ic_argv_base,
  69          (*icp->ic_argv_base != NULL ? " " : ""));
  70       fprintf(stderr, _("   Expression: %s\n"), s.s);
  71
  72       str_concat_cpa(&s, icp->ic_argv, (*icp->ic_argv != NULL ? " " : ""));
  73       fprintf(stderr, _("   Left to parse: %s\n"), s.s);
  74    }
  75
  76    NYD2_LEAVE;
  77 }
  78
  79 static si8_t
  80 _if_test(struct if_cmd *icp, bool_t noop)
  81 {
  82    char const * const *argv, *cp, *lhv, *op, *rhv;
  83    size_t argc;
  84    char c;
  85    si8_t rv = -1;
  86    NYD2_ENTER;
  87
  88    argv = icp->ic_argv;
  89    argc = PTR2SIZE(icp->ic_argv_max - icp->ic_argv);
  90    cp = argv[0];
  91
  92    if (*cp != '$') {
  93       if (argc > 1)
  94          goto jesyn;
  95    } else if (cp[1] == '\0')
  96       goto jesyn;
  97    else if (argc > 3) {
  98 jesyn:
  99       _if_error(icp, NULL, cp);
 100       goto jleave;
 101    }
 102
 103    switch (*cp) {
 104    default:
 105       switch (boolify(cp, UIZ_MAX, -1)) {
 106       case 0: rv = FAL0; break;
 107       case 1: rv = TRU1; break;
 108       default:
 109          fprintf(stderr, _("Unrecognized if-keyword: \"%s\"\n"), cp);
 110          break;
 111       }
 112       break;
 113    case 'R': case 'r':
 114       rv = !(options & OPT_SENDMODE);
 115       break;
 116    case 'S': case 's':
 117       rv = ((options & OPT_SENDMODE) != 0);
 118       break;
 119    case 'T': case 't':
 120       if (!asccasecmp(cp, "true")) /* Beware! */
 121          rv = TRU1;
 122       else
 123          rv = ((options & OPT_TTYIN) != 0);
 124       break;
 125    case '$':
 126       /* Look up the value in question, we need it anyway */
 127       ++cp;
 128       lhv = noop ? NULL : vok_vlook(cp);
 129
 130       /* Single argument, "implicit boolean" form? */
 131       if (argc == 1) {
 132          rv = (lhv != NULL);
 133          break;
 134       }
 135       op = argv[1];
 136
 137       /* Three argument comparison form required, check syntax */
 138       if (argc == 2 || (c = op[0]) == '\0')
 139          goto jesyn;
 140       if (op[1] == '\0') {
 141          if (c != '<' && c != '>')
 142             goto jesyn;
 143       } else if (op[2] != '\0')
 144          goto jesyn;
 145       else if (c == '<' || c == '>') {
 146          if (op[1] != '=')
 147             goto jesyn;
 148       } else if (c == '=' || c == '!') {
 149          if (op[1] != '=' && op[1] != '@'
 150 #ifdef HAVE_REGEX
 151                && op[1] != '~'
 152 #endif
 153          )
 154             goto jesyn;
 155       }
 156
 157       /* The right hand side may also be a variable, more syntax checking */
 158       if ((rhv = argv[2]) == NULL /* Can't happen */)
 159          goto jesyn;
 160       if (*rhv == '$') {
 161          if (*++rhv == '\0')
 162             goto jesyn;
 163          rhv = noop ? NULL : vok_vlook(rhv);
 164       }
 165
 166       /* A null value is treated as the empty string */
 167       if (lhv == NULL)
 168          lhv = UNCONST("");
 169       if (rhv == NULL)
 170          rhv = UNCONST("");
 171
 172 #ifdef HAVE_REGEX
 173       if (op[1] == '~') {
 174          regex_t re;
 175
 176          if (regcomp(&re, rhv, REG_EXTENDED | REG_ICASE | REG_NOSUB))
 177             goto jesyn;
 178          if (!noop)
 179             rv = (regexec(&re, lhv, 0,NULL, 0) == REG_NOMATCH) ^ (c == '=');
 180          regfree(&re);
 181       } else
 182 #endif
 183       if (noop)
 184          break;
 185       else if (op[1] == '@')
 186          rv = (asccasestr(lhv, rhv) == NULL) ^ (c == '=');
 187       else {
 188          /* Try to interpret as integers, prefer those, then */
 189          char *eptr;
 190          sl_i sli2, sli1;
 191
 192          sli2 = strtol(rhv, &eptr, 0);
 193          if (*rhv != '\0' && *eptr == '\0') {
 194             sli1 = strtol((cp = lhv), &eptr, 0);
 195             if (*cp != '\0' && *eptr == '\0') {
 196                sli1 -= sli2;
 197                switch (c) {
 198                default:
 199                case '=': rv = (sli1 == 0); break;
 200                case '!': rv = (sli1 != 0); break;
 201                case '<': rv = (op[1] == '\0') ? sli1 < 0 : sli1 <= 0; break;
 202                case '>': rv = (op[1] == '\0') ? sli1 > 0 : sli1 >= 0; break;
 203                }
 204                break;
 205             }
 206          }
 207
 208          /* It is not an integer, perform string comparison */
 209          sli1 = asccasecmp(lhv, rhv);
 210          switch (c) {
 211          default:
 212          case '=': rv = (sli1 == 0); break;
 213          case '!': rv = (sli1 != 0); break;
 214          case '<': rv = (op[1] == '\0') ? sli1 < 0 : sli1 <= 0; break;
 215          case '>': rv = (op[1] == '\0') ? sli1 > 0 : sli1 >= 0; break;
 216          }
 217       }
 218       break;
 219    }
 220
 221    if (noop && rv < 0)
 222       rv = TRU1;
 223 jleave:
 224    NYD2_LEAVE;
 225    return rv;
 226 }
 227
 228 static si8_t
 229 _if_group(struct if_cmd *icp, size_t level, bool_t noop)
 230 {
 231    char const *emsg = NULL, *arg0, * const *argv, * const *argv_max_save;
 232    size_t i;
 233    char unary = '\0', c;
 234    enum {
 235       _FIRST         = 1<<0,
 236       _END_OK        = 1<<1,
 237       _NEED_LIST     = 1<<2,
 238
 239       _CANNOT_UNARY  = _NEED_LIST,
 240       _CANNOT_OBRACK = _NEED_LIST,
 241       _CANNOT_CBRACK = _FIRST,
 242       _CANNOT_LIST   = _FIRST,
 243       _CANNOT_COND   = _NEED_LIST
 244    } state = _FIRST;
 245    si8_t rv = -1, xrv;
 246    NYD2_ENTER;
 247
 248    for (;;) {
 249       arg0 = *(argv = icp->ic_argv);
 250       if (arg0 == NULL) {
 251          if (!(state & _END_OK)) {
 252             emsg = N_("missing expression (premature end)");
 253             goto jesyn;
 254          }
 255          if (noop && rv < 0)
 256             rv = TRU1;
 257          break; /* goto jleave; */
 258       }
 259
 260       switch ((c = *arg0)) {
 261       case '!':
 262          if (arg0[1] != '\0')
 263             goto jneed_cond;
 264
 265          if (state & _CANNOT_UNARY) {
 266             emsg = N_("cannot use a unary operator here");
 267             goto jesyn;
 268          }
 269
 270          unary = (unary != '\0') ? '\0' : c;
 271          state &= ~(_FIRST | _END_OK);
 272          icp->ic_argv = ++argv;
 273          continue;
 274
 275       case '[':
 276       case ']':
 277          if (arg0[1] != '\0')
 278             goto jneed_cond;
 279
 280          if (c == '[') {
 281             if (state & _CANNOT_OBRACK) {
 282                emsg = N_("cannot open a group here");
 283                goto jesyn;
 284             }
 285
 286             icp->ic_argv = ++argv;
 287             if ((xrv = _if_group(icp, level + 1, noop)) < 0) {
 288                rv = xrv;
 289                goto jleave;
 290             } else if (!noop)
 291                rv = (unary != '\0') ? !xrv : xrv;
 292
 293             unary = '\0';
 294             state &= ~(_FIRST | _END_OK);
 295             state |= (level == 0 ? _END_OK : 0) | _NEED_LIST;
 296             continue;
 297          } else {
 298             if (state & _CANNOT_CBRACK) {
 299                emsg = N_("cannot use closing bracket here");
 300                goto jesyn;
 301             }
 302
 303             if (level == 0) {
 304                emsg = N_("no open groups to be closed here");
 305                goto jesyn;
 306             }
 307
 308             icp->ic_argv = ++argv;
 309             if (noop && rv < 0)
 310                rv = TRU1;
 311             goto jleave;/* break;break; */
 312          }
 313
 314       case '|':
 315       case '&':
 316          if (c != arg0[1] || arg0[2] != '\0')
 317             goto jneed_cond;
 318
 319          if (state & _CANNOT_LIST) {
 320             emsg = N_("cannot use a AND-OR list here");
 321             goto jesyn;
 322          }
 323
 324          noop = ((c == '&') ^ (rv == TRU1));
 325          state &= ~(_FIRST | _END_OK | _NEED_LIST);
 326          icp->ic_argv = ++argv;
 327          continue;
 328
 329       default:
 330    jneed_cond:
 331          if (state & _CANNOT_COND) {
 332             emsg = N_("cannot use a `if' condition here");
 333             goto jesyn;
 334          }
 335
 336          for (i = 0;; ++i) {
 337             if ((arg0 = argv[i]) == NULL)
 338                break;
 339             c = *arg0;
 340             if (c == '!' && arg0[1] == '\0')
 341                break;
 342             if ((c == '[' || c == ']') && arg0[1] == '\0')
 343                break;
 344             if ((c == '&' || c == '|') && c == arg0[1] && arg0[2] == '\0')
 345                break;
 346          }
 347          if (i == 0) {
 348             emsg = N_("empty conditional group");
 349             goto jesyn;
 350          }
 351
 352          argv_max_save = icp->ic_argv_max;
 353          icp->ic_argv_max = argv + i;
 354          if ((xrv = _if_test(icp, noop)) < 0) {
 355             rv = xrv;
 356             goto jleave;
 357          } else if (!noop)
 358             rv = (unary != '\0') ? !xrv : xrv;
 359          icp->ic_argv_max = argv_max_save;
 360
 361          icp->ic_argv = (argv += i);
 362          unary = '\0';
 363          state &= ~_FIRST;
 364          state |= _END_OK | _NEED_LIST;
 365          break;
 366       }
 367    }
 368
 369 jleave:
 370    NYD2_LEAVE;
 371    return rv;
 372 jesyn:
 373    if (emsg == NULL)
 374       emsg = N_("invalid grouping");
 375    _if_error(icp, V_(emsg), arg0);
 376    rv = -1;
 377    goto jleave;
 378 }
 379
 380 FL int
 381 c_if(void *v)
 382 {
 383    struct if_cmd ic;
 384    struct cond_stack *csp;
 385    size_t argc;
 386    si8_t xrv, rv = 1;
 387    char const * const *argv = v;
 388    NYD_ENTER;
 389
 390    csp = smalloc(sizeof *csp);
 391    csp->c_outer = _cond_stack;
 392    csp->c_error = FAL0;
 393    csp->c_noop = condstack_isskip();
 394    csp->c_go = TRU1;
 395    csp->c_else = FAL0;
 396    _cond_stack = csp;
 397
 398    if (csp->c_noop) {
 399       rv = 0;
 400       goto jleave;
 401    }
 402
 403    for (argc = 0; argv[argc] != NULL; ++argc)
 404       ;
 405    assert(argc > 0); /* (Minimum argument count for command) */
 406    ic.ic_argv_base = ic.ic_argv = argv;
 407    ic.ic_argv_max = argv + argc;
 408    xrv = _if_group(&ic, 0, FAL0);
 409
 410    if (xrv >= 0) {
 411       csp->c_go = (bool_t)xrv;
 412       rv = 0;
 413    } else
 414       csp->c_error = csp->c_noop = TRU1;
 415 jleave:
 416    NYD_LEAVE;
 417    return rv;
 418 }
 419
 420 FL int
 421 c_elif(void *v)
 422 {
 423    struct cond_stack *csp;
 424    int rv;
 425    NYD_ENTER;
 426
 427    if ((csp = _cond_stack) == NULL || csp->c_else) {
 428       fprintf(stderr, _("`elif' without matching `if'\n"));
 429       rv = 1;
 430    } else if (!csp->c_error) {
 431       csp->c_go = !csp->c_go;
 432       rv = c_if(v);
 433       _cond_stack->c_outer = csp->c_outer;
 434       free(csp);
 435    } else
 436       rv = 0;
 437    NYD_LEAVE;
 438    return rv;
 439 }
 440
 441 FL int
 442 c_else(void *v)
 443 {
 444    int rv;
 445    NYD_ENTER;
 446    UNUSED(v);
 447
 448    if (_cond_stack == NULL || _cond_stack->c_else) {
 449       fprintf(stderr, _("`else' without matching `if'\n"));
 450       rv = 1;
 451    } else {
 452       _cond_stack->c_else = TRU1;
 453       _cond_stack->c_go = !_cond_stack->c_go;
 454       rv = 0;
 455    }
 456    NYD_LEAVE;
 457    return rv;
 458 }
 459
 460 FL int
 461 c_endif(void *v)
 462 {
 463    struct cond_stack *csp;
 464    int rv;
 465    NYD_ENTER;
 466    UNUSED(v);
 467
 468    if ((csp = _cond_stack) == NULL) {
 469       fprintf(stderr, _("`endif' without matching `if'\n"));
 470       rv = 1;
 471    } else {
 472       _cond_stack = csp->c_outer;
 473       free(csp);
 474       rv = 0;
 475    }
 476    NYD_LEAVE;
 477    return rv;
 478 }
 479
 480 FL bool_t
 481 condstack_isskip(void)
 482 {
 483    bool_t rv;
 484    NYD_ENTER;
 485
 486    rv = (_cond_stack != NULL && (_cond_stack->c_noop || !_cond_stack->c_go));
 487    NYD_LEAVE;
 488    return rv;
 489 }
 490
 491 FL void *
 492 condstack_release(void)
 493 {
 494    void *rv;
 495    NYD_ENTER;
 496
 497    rv = _cond_stack;
 498    _cond_stack = NULL;
 499    NYD_LEAVE;
 500    return rv;
 501 }
 502
 503 FL bool_t
 504 condstack_take(void *self)
 505 {
 506    struct cond_stack *csp;
 507    bool_t rv;
 508    NYD_ENTER;
 509
 510    if (!(rv = ((csp = _cond_stack) == NULL)))
 511       do {
 512          _cond_stack = csp->c_outer;
 513          free(csp);
 514       } while ((csp = _cond_stack) != NULL);
 515
 516    _cond_stack = self;
 517    NYD_LEAVE;
 518    return rv;
 519 }
 520
 521 /* s-it-mode */