cmd_cnd.c

   1 /*@ S-nail - a mail user agent derived from Berkeley Mail.
   2  *@ Commands: conditional constructs.
   3  *
   4  * Copyright (c) 2014 - 2017 Steffen (Daode) Nurpmeso <steffen@sdaoden.eu>.
   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;   /* BUT: .ic_argv MUST be terminated! */
  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 ? " " : n_empty));
  70       n_err(_("   Expression: %s\n"), s.s);
  71
  72       str_concat_cpa(&s, icp->ic_argv, (*icp->ic_argv != NULL ? " " : n_empty));
  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       if(noop)
 136          lhv = NULL;
 137       else if((lhv = vok_vlook(cp)) == NULL)
 138          lhv = getenv(cp);
 139
 140       /* Single argument, "implicit boolean" form? */
 141       if (argc == 1) {
 142          rv = (lhv != NULL);
 143          break;
 144       }
 145       op = argv[1];
 146
 147       /* Three argument comparison form required, check syntax */
 148       emsg = N_("unrecognized condition");
 149       if (argc == 2 || (c = op[0]) == '\0')
 150          goto jesyn;
 151       if (op[1] == '\0') {
 152          if (c != '<' && c != '>')
 153             goto jesyn;
 154       } else if (op[2] != '\0')
 155          goto jesyn;
 156       else if (c == '<' || c == '>') {
 157          if (op[1] != '=')
 158             goto jesyn;
 159       } else if (c == '=' || c == '!') {
 160          if (op[1] != '=' && op[1] != '@'
 161 #ifdef HAVE_REGEX
 162                && op[1] != '~'
 163 #endif
 164          )
 165             goto jesyn;
 166       } else
 167          goto jesyn;
 168
 169       /* The right hand side may also be a variable, more syntax checking */
 170       emsg = N_("invalid right hand side");
 171       if ((rhv = argv[2]) == NULL /* Can't happen */)
 172          goto jesyn;
 173       if (*rhv == '$') {
 174          if (*++rhv == '\0')
 175             goto jesyn;
 176          else if(*rhv == '{'){
 177             size_t i = strlen(rhv);
 178
 179             if(i > 0 && rhv[i - 1] == '}')
 180                rhv = savestrbuf(++rhv, i -= 2);
 181             else{
 182                cp = --rhv;
 183                goto jesyn;
 184             }
 185          }
 186          if(noop)
 187             rhv = NULL;
 188          else if((rhv = vok_vlook(cp = rhv)) == NULL)
 189             rhv = getenv(cp);
 190       }
 191
 192       /* A null value is treated as the empty string */
 193       emsg = NULL;
 194       if (lhv == NULL)
 195          lhv = n_UNCONST(n_empty);
 196       if (rhv == NULL)
 197          rhv = n_UNCONST(n_empty);
 198
 199 #ifdef HAVE_REGEX
 200       if (op[1] == '~') {
 201          regex_t re;
 202
 203          if (regcomp(&re, rhv, REG_EXTENDED | REG_ICASE | REG_NOSUB)) {
 204             emsg = N_("invalid regular expression");
 205             goto jesyn;
 206          }
 207          if (!noop)
 208             rv = (regexec(&re, lhv, 0,NULL, 0) == REG_NOMATCH) ^ (c == '=');
 209          regfree(&re);
 210       } else
 211 #endif
 212       if (noop)
 213          break;
 214       else if (op[1] == '@')
 215          rv = (asccasestr(lhv, rhv) == NULL) ^ (c == '=');
 216       else {
 217          /* Try to interpret as integers, prefer those, then */
 218          char *eptr;
 219          sl_i sli2, sli1;
 220
 221          sli2 = strtol(rhv, &eptr, 0);
 222          if (*rhv != '\0' && *eptr == '\0') {
 223             sli1 = strtol((cp = lhv), &eptr, 0);
 224             if (*cp != '\0' && *eptr == '\0') {
 225                sli1 -= sli2;
 226                switch (c) {
 227                default:
 228                case '=': rv = (sli1 == 0); break;
 229                case '!': rv = (sli1 != 0); break;
 230                case '<': rv = (op[1] == '\0') ? sli1 < 0 : sli1 <= 0; break;
 231                case '>': rv = (op[1] == '\0') ? sli1 > 0 : sli1 >= 0; break;
 232                }
 233                break;
 234             }
 235          }
 236
 237          /* It is not an integer, perform string comparison */
 238          sli1 = asccasecmp(lhv, rhv);
 239          switch (c) {
 240          default:
 241          case '=': rv = (sli1 == 0); break;
 242          case '!': rv = (sli1 != 0); break;
 243          case '<': rv = (op[1] == '\0') ? sli1 < 0 : sli1 <= 0; break;
 244          case '>': rv = (op[1] == '\0') ? sli1 > 0 : sli1 >= 0; break;
 245          }
 246       }
 247       break;
 248    }
 249
 250    if (noop && rv < 0)
 251       rv = TRU1;
 252 jleave:
 253    NYD2_LEAVE;
 254    return rv;
 255 }
 256
 257 static si8_t
 258 _if_group(struct if_cmd *icp, size_t level, bool_t noop)
 259 {
 260    char const *emsg = NULL, *arg0, * const *argv, * const *argv_max_save;
 261    size_t i;
 262    char unary = '\0', c;
 263    enum {
 264       _FIRST         = 1<<0,
 265       _END_OK        = 1<<1,
 266       _NEED_LIST     = 1<<2,
 267
 268       _CANNOT_UNARY  = _NEED_LIST,
 269       _CANNOT_OBRACK = _NEED_LIST,
 270       _CANNOT_CBRACK = _FIRST,
 271       _CANNOT_LIST   = _FIRST,
 272       _CANNOT_COND   = _NEED_LIST
 273    } state = _FIRST;
 274    si8_t rv = -1, xrv;
 275    NYD2_ENTER;
 276
 277    for (;;) {
 278       arg0 = *(argv = icp->ic_argv);
 279       if (arg0 == NULL) {
 280          if (!(state & _END_OK)) {
 281             emsg = N_("missing expression (premature end)");
 282             goto jesyn;
 283          }
 284          if (noop && rv < 0)
 285             rv = TRU1;
 286          break; /* goto jleave; */
 287       }
 288
 289       switch ((c = *arg0)) {
 290       case '!':
 291          if (arg0[1] != '\0')
 292             goto jneed_cond;
 293
 294          if (state & _CANNOT_UNARY) {
 295             emsg = N_("cannot use a unary operator here");
 296             goto jesyn;
 297          }
 298
 299          unary = (unary != '\0') ? '\0' : c;
 300          state &= ~(_FIRST | _END_OK);
 301          icp->ic_argv = ++argv;
 302          continue;
 303
 304       case '[':
 305       case ']':
 306          if (arg0[1] != '\0')
 307             goto jneed_cond;
 308
 309          if (c == '[') {
 310             if (state & _CANNOT_OBRACK) {
 311                emsg = N_("cannot open a group here");
 312                goto jesyn;
 313             }
 314
 315             icp->ic_argv = ++argv;
 316             if ((xrv = _if_group(icp, level + 1, noop)) < 0) {
 317                rv = xrv;
 318                goto jleave;
 319             } else if (!noop)
 320                rv = (unary != '\0') ? !xrv : xrv;
 321
 322             unary = '\0';
 323             state &= ~(_FIRST | _END_OK);
 324             state |= (level == 0 ? _END_OK : 0) | _NEED_LIST;
 325             continue;
 326          } else {
 327             if (state & _CANNOT_CBRACK) {
 328                emsg = N_("cannot use closing bracket here");
 329                goto jesyn;
 330             }
 331
 332             if (level == 0) {
 333                emsg = N_("no open groups to be closed here");
 334                goto jesyn;
 335             }
 336
 337             icp->ic_argv = ++argv;
 338             if (noop && rv < 0)
 339                rv = TRU1;
 340             goto jleave;/* break;break; */
 341          }
 342
 343       case '|':
 344       case '&':
 345          if (c != arg0[1] || arg0[2] != '\0')
 346             goto jneed_cond;
 347
 348          if (state & _CANNOT_LIST) {
 349             emsg = N_("cannot use a AND-OR list here");
 350             goto jesyn;
 351          }
 352
 353          noop = ((c == '&') ^ (rv == TRU1));
 354          state &= ~(_FIRST | _END_OK | _NEED_LIST);
 355          icp->ic_argv = ++argv;
 356          continue;
 357
 358       default:
 359 jneed_cond:
 360          if (state & _CANNOT_COND) {
 361             emsg = N_("cannot use a `if' condition here");
 362             goto jesyn;
 363          }
 364
 365          for (i = 0;; ++i) {
 366             if ((arg0 = argv[i]) == NULL)
 367                break;
 368             c = *arg0;
 369             if (c == '!' && arg0[1] == '\0')
 370                break;
 371             if ((c == '[' || c == ']') && arg0[1] == '\0')
 372                break;
 373             if ((c == '&' || c == '|') && c == arg0[1] && arg0[2] == '\0')
 374                break;
 375          }
 376          if (i == 0) {
 377             emsg = N_("empty conditional group");
 378             goto jesyn;
 379          }
 380
 381          argv_max_save = icp->ic_argv_max;
 382          icp->ic_argv_max = argv + i;
 383          if ((xrv = _if_test(icp, noop)) < 0) {
 384             rv = xrv;
 385             goto jleave;
 386          } else if (!noop)
 387             rv = (unary != '\0') ? !xrv : xrv;
 388          icp->ic_argv_max = argv_max_save;
 389
 390          icp->ic_argv = (argv += i);
 391          unary = '\0';
 392          state &= ~_FIRST;
 393          state |= _END_OK | _NEED_LIST;
 394          break;
 395       }
 396    }
 397
 398 jleave:
 399    NYD2_LEAVE;
 400    return rv;
 401 jesyn:
 402    if (emsg == NULL)
 403       emsg = N_("invalid grouping");
 404    _if_error(icp, V_(emsg), arg0);
 405    rv = -1;
 406    goto jleave;
 407 }
 408
 409 FL int
 410 c_if(void *v)
 411 {
 412    struct if_cmd ic;
 413    char const * const *argv;
 414    struct cond_stack *csp;
 415    size_t argc;
 416    si8_t xrv, rv;
 417    NYD_ENTER;
 418
 419    csp = smalloc(sizeof *csp);
 420    csp->c_outer = _cond_stack;
 421    csp->c_error = FAL0;
 422    csp->c_noop = condstack_isskip();
 423    csp->c_go = TRU1;
 424    csp->c_else = FAL0;
 425    _cond_stack = csp;
 426
 427    if (csp->c_noop) {
 428       rv = 0;
 429       goto jleave;
 430    }
 431
 432    /* For heaven's sake, support comments _today_ TODO wyshlist.. */
 433    for (argc = 0, argv = v; argv[argc] != NULL; ++argc)
 434       if(argv[argc][0] == '#'){
 435          char const **nav = salloc(sizeof(char*) * (argc + 1));
 436          size_t i;
 437
 438          for(i = 0; i < argc; ++i)
 439             nav[i] = argv[i];
 440          nav[i] = NULL;
 441          argv = nav;
 442          break;
 443       }
 444    ic.ic_argv_base = ic.ic_argv = argv;
 445    ic.ic_argv_max = &argv[argc];
 446    xrv = _if_group(&ic, 0, FAL0);
 447
 448    if (xrv >= 0) {
 449       csp->c_go = (bool_t)xrv;
 450       rv = 0;
 451    } else {
 452       csp->c_error = csp->c_noop = TRU1;
 453       rv = 1;
 454    }
 455 jleave:
 456    NYD_LEAVE;
 457    return rv;
 458 }
 459
 460 FL int
 461 c_elif(void *v)
 462 {
 463    struct cond_stack *csp;
 464    int rv;
 465    NYD_ENTER;
 466
 467    if ((csp = _cond_stack) == NULL || csp->c_else) {
 468       n_err(_("`elif' without matching `if'\n"));
 469       rv = 1;
 470    } else if (!csp->c_error) {
 471       csp->c_go = !csp->c_go;
 472       rv = c_if(v);
 473       _cond_stack->c_outer = csp->c_outer;
 474       free(csp);
 475    } else
 476       rv = 0;
 477    NYD_LEAVE;
 478    return rv;
 479 }
 480
 481 FL int
 482 c_else(void *v)
 483 {
 484    int rv;
 485    NYD_ENTER;
 486    n_UNUSED(v);
 487
 488    if (_cond_stack == NULL || _cond_stack->c_else) {
 489       n_err(_("`else' without matching `if'\n"));
 490       rv = 1;
 491    } else {
 492       _cond_stack->c_else = TRU1;
 493       _cond_stack->c_go = !_cond_stack->c_go;
 494       rv = 0;
 495    }
 496    NYD_LEAVE;
 497    return rv;
 498 }
 499
 500 FL int
 501 c_endif(void *v)
 502 {
 503    struct cond_stack *csp;
 504    int rv;
 505    NYD_ENTER;
 506    n_UNUSED(v);
 507
 508    if ((csp = _cond_stack) == NULL) {
 509       n_err(_("`endif' without matching `if'\n"));
 510       rv = 1;
 511    } else {
 512       _cond_stack = csp->c_outer;
 513       free(csp);
 514       rv = 0;
 515    }
 516    NYD_LEAVE;
 517    return rv;
 518 }
 519
 520 FL bool_t
 521 condstack_isskip(void)
 522 {
 523    bool_t rv;
 524    NYD_ENTER;
 525
 526    rv = (_cond_stack != NULL && (_cond_stack->c_noop || !_cond_stack->c_go));
 527    NYD_LEAVE;
 528    return rv;
 529 }
 530
 531 FL void *
 532 condstack_release(void)
 533 {
 534    void *rv;
 535    NYD_ENTER;
 536
 537    rv = _cond_stack;
 538    _cond_stack = NULL;
 539    NYD_LEAVE;
 540    return rv;
 541 }
 542
 543 FL bool_t
 544 condstack_take(void *self)
 545 {
 546    struct cond_stack *csp;
 547    bool_t rv;
 548    NYD_ENTER;
 549
 550    if (!(rv = ((csp = _cond_stack) == NULL)))
 551       do {
 552          _cond_stack = csp->c_outer;
 553          free(csp);
 554       } while ((csp = _cond_stack) != NULL);
 555
 556    _cond_stack = self;
 557    NYD_LEAVE;
 558    return rv;
 559 }
 560
 561 /* s-it-mode */