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 ((n_psonce & n_PSO_INTERACTIVE) || (n_poption & n_PO_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, * const *argv, *cp, *lhv, *op, *rhv;
  83    size_t argc;
  84    char c;
  85    si8_t rv;
  86    NYD2_ENTER;
  87
  88    rv = -1;
  89    emsg = NULL;
  90    argv = icp->ic_argv;
  91    argc = PTR2SIZE(icp->ic_argv_max - icp->ic_argv);
  92    cp = argv[0];
  93
  94    if (*cp != '$') {
  95       if (argc > 1)
  96          goto jesyn;
  97    } else if (cp[1] == '\0')
  98       goto jesyn;
  99    else if (argc > 3) {
 100 #ifdef HAVE_REGEX
 101 jesyn_ntr:
 102 #endif
 103       if(0){
 104 jesyn:
 105          if(emsg != NULL)
 106             emsg = V_(emsg);
 107       }
 108       _if_error(icp, emsg, cp);
 109       goto jleave;
 110    }
 111
 112    switch (*cp) {
 113    default:
 114       switch (boolify(cp, UIZ_MAX, -1)) {
 115       case 0: rv = FAL0; break;
 116       case 1: rv = TRU1; break;
 117       default:
 118          emsg = N_("Expected a boolean");
 119          goto jesyn;
 120       }
 121       break;
 122    case 'R': case 'r':
 123       rv = !(n_psonce & n_PSO_SENDMODE);
 124       break;
 125    case 'S': case 's':
 126       rv = ((n_psonce & n_PSO_SENDMODE) != 0);
 127       break;
 128    case 'T': case 't':
 129       if (!asccasecmp(cp, "true")) /* Beware! */
 130          rv = TRU1;
 131       else
 132          rv = ((n_psonce & n_PSO_TTYIN) != 0);
 133       break;
 134    case '$':
 135       /* Look up the value in question, we need it anyway */
 136       if(*++cp == '{'){
 137          size_t i = strlen(cp);
 138
 139          if(i > 0 && cp[i - 1] == '}')
 140             cp = savestrbuf(++cp, i -= 2);
 141          else
 142             goto jesyn;
 143       }
 144       if(noop)
 145          lhv = NULL;
 146       else
 147          lhv = n_var_vlook(cp, TRU1);
 148
 149       /* Single argument, "implicit boolean" form? */
 150       if (argc == 1) {
 151          rv = (lhv != NULL);
 152          break;
 153       }
 154       op = argv[1];
 155
 156       /* Three argument comparison form required, check syntax */
 157       emsg = N_("unrecognized condition");
 158       if (argc == 2 || (c = op[0]) == '\0')
 159          goto jesyn;
 160       if (op[1] == '\0') {
 161          if (c != '<' && c != '>')
 162             goto jesyn;
 163       } else if (op[2] != '\0')
 164          goto jesyn;
 165       else if (c == '<' || c == '>') {
 166          if (op[1] != '=')
 167             goto jesyn;
 168       } else if (c == '=' || c == '!') {
 169          if (op[1] != '=' && op[1] != '@'
 170 #ifdef HAVE_REGEX
 171                && op[1] != '~'
 172 #endif
 173          )
 174             goto jesyn;
 175       } else
 176          goto jesyn;
 177
 178       /* The right hand side may also be a variable, more syntax checking */
 179       emsg = N_("invalid right hand side");
 180       if ((rhv = argv[2]) == NULL /* Can't happen */)
 181          goto jesyn;
 182       if (*rhv == '$') {
 183          if (*++rhv == '\0')
 184             goto jesyn;
 185          else if(*rhv == '{'){
 186             size_t i = strlen(rhv);
 187
 188             if(i > 0 && rhv[i - 1] == '}')
 189                rhv = savestrbuf(++rhv, i -= 2);
 190             else{
 191                cp = --rhv;
 192                goto jesyn;
 193             }
 194          }
 195          if(noop)
 196             rhv = NULL;
 197          else
 198             rhv = n_var_vlook(cp = rhv, TRU1);
 199       }
 200
 201       /* A null value is treated as the empty string */
 202       emsg = NULL;
 203       if (lhv == NULL)
 204          lhv = n_UNCONST(n_empty);
 205       if (rhv == NULL)
 206          rhv = n_UNCONST(n_empty);
 207
 208 #ifdef HAVE_REGEX
 209       if (op[1] == '~') {
 210          regex_t re;
 211          int s;
 212
 213          if((s = regcomp(&re, rhv, REG_EXTENDED | REG_ICASE | REG_NOSUB)) != 0){
 214             emsg = savecat(_("invalid regular expression: "),
 215                   n_regex_err_to_str(&re, s));
 216             goto jesyn_ntr;
 217          }
 218          if (!noop)
 219             rv = (regexec(&re, lhv, 0,NULL, 0) == REG_NOMATCH) ^ (c == '=');
 220          regfree(&re);
 221       } else
 222 #endif
 223       if (noop)
 224          break;
 225       else if (op[1] == '@')
 226          rv = (asccasestr(lhv, rhv) == NULL) ^ (c == '=');
 227       else {
 228          /* Try to interpret as integers, prefer those, then */
 229          char *eptr;
 230          sl_i sli2, sli1;
 231
 232          sli2 = strtol(rhv, &eptr, 0);
 233          if (*rhv != '\0' && *eptr == '\0') {
 234             sli1 = strtol((cp = lhv), &eptr, 0);
 235             if (*cp != '\0' && *eptr == '\0') {
 236                sli1 -= sli2;
 237                switch (c) {
 238                default:
 239                case '=': rv = (sli1 == 0); break;
 240                case '!': rv = (sli1 != 0); break;
 241                case '<': rv = (op[1] == '\0') ? sli1 < 0 : sli1 <= 0; break;
 242                case '>': rv = (op[1] == '\0') ? sli1 > 0 : sli1 >= 0; break;
 243                }
 244                break;
 245             }
 246          }
 247
 248          /* It is not an integer, perform string comparison */
 249          sli1 = asccasecmp(lhv, rhv);
 250          switch (c) {
 251          default:
 252          case '=': rv = (sli1 == 0); break;
 253          case '!': rv = (sli1 != 0); break;
 254          case '<': rv = (op[1] == '\0') ? sli1 < 0 : sli1 <= 0; break;
 255          case '>': rv = (op[1] == '\0') ? sli1 > 0 : sli1 >= 0; break;
 256          }
 257       }
 258       break;
 259    }
 260
 261    if (noop && rv < 0)
 262       rv = TRU1;
 263 jleave:
 264    NYD2_LEAVE;
 265    return rv;
 266 }
 267
 268 static si8_t
 269 _if_group(struct if_cmd *icp, size_t level, bool_t noop)
 270 {
 271    char const *emsg = NULL, *arg0, * const *argv, * const *argv_max_save;
 272    size_t i;
 273    char unary = '\0', c;
 274    enum {
 275       _FIRST         = 1<<0,
 276       _END_OK        = 1<<1,
 277       _NEED_LIST     = 1<<2,
 278
 279       _CANNOT_UNARY  = _NEED_LIST,
 280       _CANNOT_OBRACK = _NEED_LIST,
 281       _CANNOT_CBRACK = _FIRST,
 282       _CANNOT_LIST   = _FIRST,
 283       _CANNOT_COND   = _NEED_LIST
 284    } state = _FIRST;
 285    si8_t rv = -1, xrv;
 286    NYD2_ENTER;
 287
 288    for (;;) {
 289       arg0 = *(argv = icp->ic_argv);
 290       if (arg0 == NULL) {
 291          if (!(state & _END_OK)) {
 292             emsg = N_("missing expression (premature end)");
 293             goto jesyn;
 294          }
 295          if (noop && rv < 0)
 296             rv = TRU1;
 297          break; /* goto jleave; */
 298       }
 299
 300       switch ((c = *arg0)) {
 301       case '!':
 302          if (arg0[1] != '\0')
 303             goto jneed_cond;
 304
 305          if (state & _CANNOT_UNARY) {
 306             emsg = N_("cannot use a unary operator here");
 307             goto jesyn;
 308          }
 309
 310          unary = (unary != '\0') ? '\0' : c;
 311          state &= ~(_FIRST | _END_OK);
 312          icp->ic_argv = ++argv;
 313          continue;
 314
 315       case '[':
 316       case ']':
 317          if (arg0[1] != '\0')
 318             goto jneed_cond;
 319
 320          if (c == '[') {
 321             if (state & _CANNOT_OBRACK) {
 322                emsg = N_("cannot open a group here");
 323                goto jesyn;
 324             }
 325
 326             icp->ic_argv = ++argv;
 327             if ((xrv = _if_group(icp, level + 1, noop)) < 0) {
 328                rv = xrv;
 329                goto jleave;
 330             } else if (!noop)
 331                rv = (unary != '\0') ? !xrv : xrv;
 332
 333             unary = '\0';
 334             state &= ~(_FIRST | _END_OK);
 335             state |= (level == 0 ? _END_OK : 0) | _NEED_LIST;
 336             continue;
 337          } else {
 338             if (state & _CANNOT_CBRACK) {
 339                emsg = N_("cannot use closing bracket here");
 340                goto jesyn;
 341             }
 342
 343             if (level == 0) {
 344                emsg = N_("no open groups to be closed here");
 345                goto jesyn;
 346             }
 347
 348             icp->ic_argv = ++argv;
 349             if (noop && rv < 0)
 350                rv = TRU1;
 351             goto jleave;/* break;break; */
 352          }
 353
 354       case '|':
 355       case '&':
 356          if (c != arg0[1] || arg0[2] != '\0')
 357             goto jneed_cond;
 358
 359          if (state & _CANNOT_LIST) {
 360             emsg = N_("cannot use a AND-OR list here");
 361             goto jesyn;
 362          }
 363
 364          noop = ((c == '&') ^ (rv == TRU1));
 365          state &= ~(_FIRST | _END_OK | _NEED_LIST);
 366          icp->ic_argv = ++argv;
 367          continue;
 368
 369       default:
 370 jneed_cond:
 371          if (state & _CANNOT_COND) {
 372             emsg = N_("cannot use a `if' condition here");
 373             goto jesyn;
 374          }
 375
 376          for (i = 0;; ++i) {
 377             if ((arg0 = argv[i]) == NULL)
 378                break;
 379             c = *arg0;
 380             if (c == '!' && arg0[1] == '\0')
 381                break;
 382             if ((c == '[' || c == ']') && arg0[1] == '\0')
 383                break;
 384             if ((c == '&' || c == '|') && c == arg0[1] && arg0[2] == '\0')
 385                break;
 386          }
 387          if (i == 0) {
 388             emsg = N_("empty conditional group");
 389             goto jesyn;
 390          }
 391
 392          argv_max_save = icp->ic_argv_max;
 393          icp->ic_argv_max = argv + i;
 394          if ((xrv = _if_test(icp, noop)) < 0) {
 395             rv = xrv;
 396             goto jleave;
 397          } else if (!noop)
 398             rv = (unary != '\0') ? !xrv : xrv;
 399          icp->ic_argv_max = argv_max_save;
 400
 401          icp->ic_argv = (argv += i);
 402          unary = '\0';
 403          state &= ~_FIRST;
 404          state |= _END_OK | _NEED_LIST;
 405          break;
 406       }
 407    }
 408
 409 jleave:
 410    NYD2_LEAVE;
 411    return rv;
 412 jesyn:
 413    if (emsg == NULL)
 414       emsg = N_("invalid grouping");
 415    _if_error(icp, V_(emsg), arg0);
 416    rv = -1;
 417    goto jleave;
 418 }
 419
 420 FL int
 421 c_if(void *v)
 422 {
 423    struct if_cmd ic;
 424    char const * const *argv;
 425    struct cond_stack *csp;
 426    size_t argc;
 427    si8_t xrv, rv;
 428    NYD_ENTER;
 429
 430    csp = smalloc(sizeof *csp);
 431    csp->c_outer = _cond_stack;
 432    csp->c_error = FAL0;
 433    csp->c_noop = condstack_isskip();
 434    csp->c_go = TRU1;
 435    csp->c_else = FAL0;
 436    _cond_stack = csp;
 437
 438    if (csp->c_noop) {
 439       rv = 0;
 440       goto jleave;
 441    }
 442
 443    /* For heaven's sake, support comments _today_ TODO wyshlist.. */
 444    for (argc = 0, argv = v; argv[argc] != NULL; ++argc)
 445       if(argv[argc][0] == '#'){
 446          char const **nav = salloc(sizeof(char*) * (argc + 1));
 447          size_t i;
 448
 449          for(i = 0; i < argc; ++i)
 450             nav[i] = argv[i];
 451          nav[i] = NULL;
 452          argv = nav;
 453          break;
 454       }
 455    ic.ic_argv_base = ic.ic_argv = argv;
 456    ic.ic_argv_max = &argv[argc];
 457    xrv = _if_group(&ic, 0, FAL0);
 458
 459    if (xrv >= 0) {
 460       csp->c_go = (bool_t)xrv;
 461       rv = 0;
 462    } else {
 463       csp->c_error = csp->c_noop = TRU1;
 464       rv = 1;
 465    }
 466 jleave:
 467    NYD_LEAVE;
 468    return rv;
 469 }
 470
 471 FL int
 472 c_elif(void *v)
 473 {
 474    struct cond_stack *csp;
 475    int rv;
 476    NYD_ENTER;
 477
 478    if ((csp = _cond_stack) == NULL || csp->c_else) {
 479       n_err(_("`elif' without matching `if'\n"));
 480       rv = 1;
 481    } else if (!csp->c_error) {
 482       csp->c_go = !csp->c_go;
 483       rv = c_if(v);
 484       _cond_stack->c_outer = csp->c_outer;
 485       free(csp);
 486    } else
 487       rv = 0;
 488    NYD_LEAVE;
 489    return rv;
 490 }
 491
 492 FL int
 493 c_else(void *v)
 494 {
 495    int rv;
 496    NYD_ENTER;
 497    n_UNUSED(v);
 498
 499    if (_cond_stack == NULL || _cond_stack->c_else) {
 500       n_err(_("`else' without matching `if'\n"));
 501       rv = 1;
 502    } else {
 503       _cond_stack->c_else = TRU1;
 504       _cond_stack->c_go = !_cond_stack->c_go;
 505       rv = 0;
 506    }
 507    NYD_LEAVE;
 508    return rv;
 509 }
 510
 511 FL int
 512 c_endif(void *v)
 513 {
 514    struct cond_stack *csp;
 515    int rv;
 516    NYD_ENTER;
 517    n_UNUSED(v);
 518
 519    if ((csp = _cond_stack) == NULL) {
 520       n_err(_("`endif' without matching `if'\n"));
 521       rv = 1;
 522    } else {
 523       _cond_stack = csp->c_outer;
 524       free(csp);
 525       rv = 0;
 526    }
 527    NYD_LEAVE;
 528    return rv;
 529 }
 530
 531 FL bool_t
 532 condstack_isskip(void)
 533 {
 534    bool_t rv;
 535    NYD_ENTER;
 536
 537    rv = (_cond_stack != NULL && (_cond_stack->c_noop || !_cond_stack->c_go));
 538    NYD_LEAVE;
 539    return rv;
 540 }
 541
 542 FL void *
 543 condstack_release(void)
 544 {
 545    void *rv;
 546    NYD_ENTER;
 547
 548    rv = _cond_stack;
 549    _cond_stack = NULL;
 550    NYD_LEAVE;
 551    return rv;
 552 }
 553
 554 FL bool_t
 555 condstack_take(void *self)
 556 {
 557    struct cond_stack *csp;
 558    bool_t rv;
 559    NYD_ENTER;
 560
 561    if (!(rv = ((csp = _cond_stack) == NULL)))
 562       do {
 563          _cond_stack = csp->c_outer;
 564          free(csp);
 565       } while ((csp = _cond_stack) != NULL);
 566
 567    _cond_stack = self;
 568    NYD_LEAVE;
 569    return rv;
 570 }
 571
 572 /* s-it-mode */