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       n_err(_("`if' conditional: %s -- near \"%s\"\n"),
  63          msg_or_null, nearby_or_null);
  64    else
  65       n_err(_("`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       n_err(_("   Expression: %s\n"), s.s);
  71
  72       str_concat_cpa(&s, icp->ic_argv, (*icp->ic_argv != NULL ? " " : ""));
  73       n_err(_("   Stopped at: %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 *emsg = NULL, * 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 != '$') {
  93       if (argc > 1)
  94          goto jesyn;
  95    } else if (cp[1] == '\0')
  96       goto jesyn;
  97    else if (argc > 3) {
  98 jesyn:
  99       _if_error(icp, emsg, cp);
 100       goto jleave;
 101    }
 102
 103    switch (*cp) {
 104    default:
 105       switch (boolify(cp, UIZ_MAX, -1)) {
 106       case 0: rv = FAL0; break;
 107       case 1: rv = TRU1; break;
 108       default:
 109          emsg = N_("Expected a boolean");
 110          goto jesyn;
 111       }
 112       break;
 113    case 'R': case 'r':
 114       rv = !(options & OPT_SENDMODE);
 115       break;
 116    case 'S': case 's':
 117       rv = ((options & OPT_SENDMODE) != 0);
 118       break;
 119    case 'T': case 't':
 120       if (!asccasecmp(cp, "true")) /* Beware! */
 121          rv = TRU1;
 122       else
 123          rv = ((options & OPT_TTYIN) != 0);
 124       break;
 125    case '$':
 126       /* Look up the value in question, we need it anyway */
 127       if(*++cp == '{'){
 128          size_t i = strlen(cp);
 129
 130          if(i > 0 && cp[i - 1] == '}')
 131             cp = savestrbuf(++cp, i -= 2);
 132          else
 133             goto jesyn;
 134       }
 135       lhv = noop ? NULL : vok_vlook(cp);
 136
 137       /* Single argument, "implicit boolean" form? */
 138       if (argc == 1) {
 139          rv = (lhv != NULL);
 140          break;
 141       }
 142       op = argv[1];
 143
 144       /* Three argument comparison form required, check syntax */
 145       emsg = N_("unrecognized condition");
 146       if (argc == 2 || (c = op[0]) == '\0')
 147          goto jesyn;
 148       if (op[1] == '\0') {
 149          if (c != '<' && c != '>')
 150             goto jesyn;
 151       } else if (op[2] != '\0')
 152          goto jesyn;
 153       else if (c == '<' || c == '>') {
 154          if (op[1] != '=')
 155             goto jesyn;
 156       } else if (c == '=' || c == '!') {
 157          if (op[1] != '=' && op[1] != '@'
 158 #ifdef HAVE_REGEX
 159                && op[1] != '~'
 160 #endif
 161          )
 162             goto jesyn;
 163       } else
 164          goto jesyn;
 165
 166       /* The right hand side may also be a variable, more syntax checking */
 167       emsg = N_("invalid right hand side");
 168       if ((rhv = argv[2]) == NULL /* Can't happen */)
 169          goto jesyn;
 170       if (*rhv == '$') {
 171          if (*++rhv == '\0')
 172             goto jesyn;
 173          else if(*rhv == '{'){
 174             size_t i = strlen(rhv);
 175
 176             if(i > 0 && rhv[i - 1] == '}')
 177                rhv = savestrbuf(++rhv, i -= 2);
 178             else{
 179                cp = --rhv;
 180                goto jesyn;
 181             }
 182          }
 183          rhv = noop ? NULL : vok_vlook(rhv);
 184       }
 185
 186       /* A null value is treated as the empty string */
 187       emsg = NULL;
 188       if (lhv == NULL)
 189          lhv = UNCONST("");
 190       if (rhv == NULL)
 191          rhv = UNCONST("");
 192
 193 #ifdef HAVE_REGEX
 194       if (op[1] == '~') {
 195          regex_t re;
 196
 197          if (regcomp(&re, rhv, REG_EXTENDED | REG_ICASE | REG_NOSUB)) {
 198             emsg = N_("invalid regular expression");
 199             goto jesyn;
 200          }
 201          if (!noop)
 202             rv = (regexec(&re, lhv, 0,NULL, 0) == REG_NOMATCH) ^ (c == '=');
 203          regfree(&re);
 204       } else
 205 #endif
 206       if (noop)
 207          break;
 208       else if (op[1] == '@')
 209          rv = (asccasestr(lhv, rhv) == NULL) ^ (c == '=');
 210       else {
 211          /* Try to interpret as integers, prefer those, then */
 212          char *eptr;
 213          sl_i sli2, sli1;
 214
 215          sli2 = strtol(rhv, &eptr, 0);
 216          if (*rhv != '\0' && *eptr == '\0') {
 217             sli1 = strtol((cp = lhv), &eptr, 0);
 218             if (*cp != '\0' && *eptr == '\0') {
 219                sli1 -= sli2;
 220                switch (c) {
 221                default:
 222                case '=': rv = (sli1 == 0); break;
 223                case '!': rv = (sli1 != 0); break;
 224                case '<': rv = (op[1] == '\0') ? sli1 < 0 : sli1 <= 0; break;
 225                case '>': rv = (op[1] == '\0') ? sli1 > 0 : sli1 >= 0; break;
 226                }
 227                break;
 228             }
 229          }
 230
 231          /* It is not an integer, perform string comparison */
 232          sli1 = asccasecmp(lhv, rhv);
 233          switch (c) {
 234          default:
 235          case '=': rv = (sli1 == 0); break;
 236          case '!': rv = (sli1 != 0); break;
 237          case '<': rv = (op[1] == '\0') ? sli1 < 0 : sli1 <= 0; break;
 238          case '>': rv = (op[1] == '\0') ? sli1 > 0 : sli1 >= 0; break;
 239          }
 240       }
 241       break;
 242    }
 243
 244    if (noop && rv < 0)
 245       rv = TRU1;
 246 jleave:
 247    NYD2_LEAVE;
 248    return rv;
 249 }
 250
 251 static si8_t
 252 _if_group(struct if_cmd *icp, size_t level, bool_t noop)
 253 {
 254    char const *emsg = NULL, *arg0, * const *argv, * const *argv_max_save;
 255    size_t i;
 256    char unary = '\0', c;
 257    enum {
 258       _FIRST         = 1<<0,
 259       _END_OK        = 1<<1,
 260       _NEED_LIST     = 1<<2,
 261
 262       _CANNOT_UNARY  = _NEED_LIST,
 263       _CANNOT_OBRACK = _NEED_LIST,
 264       _CANNOT_CBRACK = _FIRST,
 265       _CANNOT_LIST   = _FIRST,
 266       _CANNOT_COND   = _NEED_LIST
 267    } state = _FIRST;
 268    si8_t rv = -1, xrv;
 269    NYD2_ENTER;
 270
 271    for (;;) {
 272       arg0 = *(argv = icp->ic_argv);
 273       if (arg0 == NULL) {
 274          if (!(state & _END_OK)) {
 275             emsg = N_("missing expression (premature end)");
 276             goto jesyn;
 277          }
 278          if (noop && rv < 0)
 279             rv = TRU1;
 280          break; /* goto jleave; */
 281       }
 282
 283       switch ((c = *arg0)) {
 284       case '!':
 285          if (arg0[1] != '\0')
 286             goto jneed_cond;
 287
 288          if (state & _CANNOT_UNARY) {
 289             emsg = N_("cannot use a unary operator here");
 290             goto jesyn;
 291          }
 292
 293          unary = (unary != '\0') ? '\0' : c;
 294          state &= ~(_FIRST | _END_OK);
 295          icp->ic_argv = ++argv;
 296          continue;
 297
 298       case '[':
 299       case ']':
 300          if (arg0[1] != '\0')
 301             goto jneed_cond;
 302
 303          if (c == '[') {
 304             if (state & _CANNOT_OBRACK) {
 305                emsg = N_("cannot open a group here");
 306                goto jesyn;
 307             }
 308
 309             icp->ic_argv = ++argv;
 310             if ((xrv = _if_group(icp, level + 1, noop)) < 0) {
 311                rv = xrv;
 312                goto jleave;
 313             } else if (!noop)
 314                rv = (unary != '\0') ? !xrv : xrv;
 315
 316             unary = '\0';
 317             state &= ~(_FIRST | _END_OK);
 318             state |= (level == 0 ? _END_OK : 0) | _NEED_LIST;
 319             continue;
 320          } else {
 321             if (state & _CANNOT_CBRACK) {
 322                emsg = N_("cannot use closing bracket here");
 323                goto jesyn;
 324             }
 325
 326             if (level == 0) {
 327                emsg = N_("no open groups to be closed here");
 328                goto jesyn;
 329             }
 330
 331             icp->ic_argv = ++argv;
 332             if (noop && rv < 0)
 333                rv = TRU1;
 334             goto jleave;/* break;break; */
 335          }
 336
 337       case '|':
 338       case '&':
 339          if (c != arg0[1] || arg0[2] != '\0')
 340             goto jneed_cond;
 341
 342          if (state & _CANNOT_LIST) {
 343             emsg = N_("cannot use a AND-OR list here");
 344             goto jesyn;
 345          }
 346
 347          noop = ((c == '&') ^ (rv == TRU1));
 348          state &= ~(_FIRST | _END_OK | _NEED_LIST);
 349          icp->ic_argv = ++argv;
 350          continue;
 351
 352       default:
 353 jneed_cond:
 354          if (state & _CANNOT_COND) {
 355             emsg = N_("cannot use a `if' condition here");
 356             goto jesyn;
 357          }
 358
 359          for (i = 0;; ++i) {
 360             if ((arg0 = argv[i]) == NULL)
 361                break;
 362             c = *arg0;
 363             if (c == '!' && arg0[1] == '\0')
 364                break;
 365             if ((c == '[' || c == ']') && arg0[1] == '\0')
 366                break;
 367             if ((c == '&' || c == '|') && c == arg0[1] && arg0[2] == '\0')
 368                break;
 369          }
 370          if (i == 0) {
 371             emsg = N_("empty conditional group");
 372             goto jesyn;
 373          }
 374
 375          argv_max_save = icp->ic_argv_max;
 376          icp->ic_argv_max = argv + i;
 377          if ((xrv = _if_test(icp, noop)) < 0) {
 378             rv = xrv;
 379             goto jleave;
 380          } else if (!noop)
 381             rv = (unary != '\0') ? !xrv : xrv;
 382          icp->ic_argv_max = argv_max_save;
 383
 384          icp->ic_argv = (argv += i);
 385          unary = '\0';
 386          state &= ~_FIRST;
 387          state |= _END_OK | _NEED_LIST;
 388          break;
 389       }
 390    }
 391
 392 jleave:
 393    NYD2_LEAVE;
 394    return rv;
 395 jesyn:
 396    if (emsg == NULL)
 397       emsg = N_("invalid grouping");
 398    _if_error(icp, V_(emsg), arg0);
 399    rv = -1;
 400    goto jleave;
 401 }
 402
 403 FL int
 404 c_if(void *v)
 405 {
 406    struct if_cmd ic;
 407    struct cond_stack *csp;
 408    size_t argc;
 409    si8_t xrv, rv = 1;
 410    char const * const *argv = v;
 411    NYD_ENTER;
 412
 413    csp = smalloc(sizeof *csp);
 414    csp->c_outer = _cond_stack;
 415    csp->c_error = FAL0;
 416    csp->c_noop = condstack_isskip();
 417    csp->c_go = TRU1;
 418    csp->c_else = FAL0;
 419    _cond_stack = csp;
 420
 421    if (csp->c_noop) {
 422       rv = 0;
 423       goto jleave;
 424    }
 425
 426    for (argc = 0; argv[argc] != NULL; ++argc)
 427       ;
 428    assert(argc > 0); /* (Minimum argument count for command) */
 429    ic.ic_argv_base = ic.ic_argv = argv;
 430    ic.ic_argv_max = argv + argc;
 431    xrv = _if_group(&ic, 0, FAL0);
 432
 433    if (xrv >= 0) {
 434       csp->c_go = (bool_t)xrv;
 435       rv = 0;
 436    } else
 437       csp->c_error = csp->c_noop = TRU1;
 438 jleave:
 439    NYD_LEAVE;
 440    return rv;
 441 }
 442
 443 FL int
 444 c_elif(void *v)
 445 {
 446    struct cond_stack *csp;
 447    int rv;
 448    NYD_ENTER;
 449
 450    if ((csp = _cond_stack) == NULL || csp->c_else) {
 451       n_err(_("`elif' without matching `if'\n"));
 452       rv = 1;
 453    } else if (!csp->c_error) {
 454       csp->c_go = !csp->c_go;
 455       rv = c_if(v);
 456       _cond_stack->c_outer = csp->c_outer;
 457       free(csp);
 458    } else
 459       rv = 0;
 460    NYD_LEAVE;
 461    return rv;
 462 }
 463
 464 FL int
 465 c_else(void *v)
 466 {
 467    int rv;
 468    NYD_ENTER;
 469    UNUSED(v);
 470
 471    if (_cond_stack == NULL || _cond_stack->c_else) {
 472       n_err(_("`else' without matching `if'\n"));
 473       rv = 1;
 474    } else {
 475       _cond_stack->c_else = TRU1;
 476       _cond_stack->c_go = !_cond_stack->c_go;
 477       rv = 0;
 478    }
 479    NYD_LEAVE;
 480    return rv;
 481 }
 482
 483 FL int
 484 c_endif(void *v)
 485 {
 486    struct cond_stack *csp;
 487    int rv;
 488    NYD_ENTER;
 489    UNUSED(v);
 490
 491    if ((csp = _cond_stack) == NULL) {
 492       n_err(_("`endif' without matching `if'\n"));
 493       rv = 1;
 494    } else {
 495       _cond_stack = csp->c_outer;
 496       free(csp);
 497       rv = 0;
 498    }
 499    NYD_LEAVE;
 500    return rv;
 501 }
 502
 503 FL bool_t
 504 condstack_isskip(void)
 505 {
 506    bool_t rv;
 507    NYD_ENTER;
 508
 509    rv = (_cond_stack != NULL && (_cond_stack->c_noop || !_cond_stack->c_go));
 510    NYD_LEAVE;
 511    return rv;
 512 }
 513
 514 FL void *
 515 condstack_release(void)
 516 {
 517    void *rv;
 518    NYD_ENTER;
 519
 520    rv = _cond_stack;
 521    _cond_stack = NULL;
 522    NYD_LEAVE;
 523    return rv;
 524 }
 525
 526 FL bool_t
 527 condstack_take(void *self)
 528 {
 529    struct cond_stack *csp;
 530    bool_t rv;
 531    NYD_ENTER;
 532
 533    if (!(rv = ((csp = _cond_stack) == NULL)))
 534       do {
 535          _cond_stack = csp->c_outer;
 536          free(csp);
 537       } while ((csp = _cond_stack) != NULL);
 538
 539    _cond_stack = self;
 540    NYD_LEAVE;
 541    return rv;
 542 }
 543
 544 /* s-it-mode */