src/scan.c

   1 /*
   2  * Copyright 1993-2002 Christopher Seiwald and Perforce Software, Inc.
   3  *
   4  * This file is part of Jam - see jam.c for Copyright information.
   5  */
   6 /*
   7  * scan.c - the jam yacc scanner
   8  *
   9  * 12/26/93 (seiwald) - bump buf in yylex to 10240 - yuk.
  10  * 09/16/94 (seiwald) - check for overflows, unmatched {}'s, etc.
  11  *                      Also handle tokens abutting EOF by remembering
  12  *                      to return EOF now matter how many times yylex()
  13  *                      reinvokes yyline().
  14  * 02/11/95 (seiwald) - honor only punctuation keywords if SCAN_PUNCT.
  15  * 07/27/95 (seiwald) - Include jamgram.h after scan.h, so that YYSTYPE is
  16  *                      defined before Linux's yacc tries to redefine it.
  17  * 01/10/01 (seiwald) - \ can now escape any whitespace char
  18  * 11/04/02 (seiwald) - const-ing for string literals
  19  */
  20 #include "jam.h"
  21 #include "lists.h"
  22 #include "parse.h"
  23 #include "scan.h"
  24 #include "jamgram.h"
  25 #include "jambase.h"
  26 #include "newstr.h"
  27 #include "dstrings.h"
  28
  29
  30 token_t yylval;
  31
  32
  33 typedef struct {
  34   const char *word;
  35   int type;
  36 } keyword_t;
  37
  38
  39 static const keyword_t keywords[] = {
  40 #include "jamgramtab.h"
  41   {0,0}
  42 };
  43
  44
  45 typedef struct include_s {
  46   struct include_s *next; /* next serial include file */
  47   const char *string; /* pointer into current line */
  48   char **strings; /* for yyfparse() -- text to parse */
  49   FILE *file; /* for yyfparse() -- file being read */
  50   const char *fname; /* for yyfparse() -- file name */
  51   int line; /* line counter for error messages */
  52   int pos; /* position for error messages */
  53   int back_count; /* # of yyunget()ed chars */
  54   char back_chars[2]; /* buffer for yyunget()ed chars */
  55   char *fcontents; /* for yyfparse() -- file contents */
  56   int prevwasn; /* !0: increment line and reset to 0 */
  57 } include_t;
  58
  59 static include_t *incp = NULL; /* current file; head of chain */
  60
  61
  62 static int scan_mode = SCAN_NORMAL;
  63 /*static int any_errors = 0;*/
  64
  65 static const char *symdump (const token_t *s);
  66
  67
  68 #ifndef NDEBUG
  69 static const char *mnames[] = {
  70   "SCAN_NORMAL",
  71   "SCAN_STRING",
  72   "SCAN_PUNCT",
  73 };
  74 #endif
  75
  76
  77 /*
  78  * Set parser mode: normal, string, or keyword
  79  */
  80 void yymode (int n) {
  81 #ifndef NDEBUG
  82   if (DEBUG_SCAN && scan_mode != n) printf("**MODE TRANSITION: %s --> %s\n", mnames[scan_mode], mnames[n]);
  83 #endif
  84   scan_mode = n;
  85 }
  86
  87
  88 void yyerror (const token_t *tk, const char *s) {
  89   printf("ERROR(%d:%d) '%s': %s\n", tk->line, tk->pos, tk->file, s);
  90   exit(EXITBAD); /* exit now */
  91 }
  92
  93
  94 static void yywarning_ex (const char *s) {
  95   printf("WARNING(%d:%d) '%s': %s\n", incp->line, incp->pos, incp->fname, s);
  96 }
  97
  98
  99 void yyfparse (const char *s) {
 100   include_t *i = (include_t *)malloc(sizeof(*i));
 101   /* push this onto the incp chain */
 102   i->string = "";
 103   i->strings = NULL;
 104   i->file = NULL;
 105   //i->fname = strdup(s);
 106   i->fname = newstr(s);
 107   i->line = 0;
 108   i->pos = 0;
 109   i->next = incp;
 110   i->back_count = 0;
 111   i->fcontents = NULL;
 112   i->prevwasn = 1;
 113   incp = i;
 114   /* if the filename is "::Jambase", it means use the internal jambase */
 115   if (strcmp(s, "::Jambase") == 0) {
 116     jambase_unpack();
 117     i->strings = jambase;
 118   }
 119 }
 120
 121
 122 /*
 123  * yychar() - read new line and return first character
 124  *
 125  * fabricates a continuous stream of characters across include files, returning EOF at the bitter end
 126  */
 127 static int yychar (void) {
 128   include_t *i = incp;
 129   if (!incp) return EOF;
 130   /* once we start reading from the input stream, we reset the
 131    * include insertion point so that the next include file becomes
 132    * the head of the list */
 133   if (i->back_count) return i->back_chars[--i->back_count];
 134   /* if there is more data in this line, return it */
 135   if (i->prevwasn) { i->prevwasn = 0; ++i->line; i->pos = 0; }
 136 again:
 137   ++i->pos;
 138   if (*i->string) {
 139     if (*i->string == '\n') i->prevwasn = 1;
 140     return *i->string++;
 141   }
 142   /* if we're reading from an internal string list, go to the next string */
 143   if (i->strings) {
 144     if (!*i->strings) goto next;
 145     i->string = *(i->strings++);
 146     return *i->string++;
 147   }
 148   /* if necessary, open the file and get file contents */
 149   if (!i->file) {
 150     FILE *f;
 151     long fsize;
 152     if ((f = fopen(i->fname, "rb")) == NULL) perror(i->fname);
 153     i->file = f;
 154     if (fseek(f, 0, SEEK_END) < 0) perror(i->fname);
 155     if ((fsize = ftell(f)) < 0) perror(i->fname);
 156     if (fseek(f, 0, SEEK_SET) < 0) perror(i->fname);
 157     i->fcontents = calloc(fsize+1, 1);
 158     if (fsize > 0 && fread(i->fcontents, fsize, 1, f) != 1) perror(i->fname);
 159     fclose(f); /* don't need to hold it opened */
 160     i->string = i->fcontents;
 161     goto again;
 162   }
 163 next:
 164   /* this include is done */
 165   /* free it up and return EOF so yyparse() returns to parse_file() */
 166   incp = i->next;
 167   /* close file, free name */
 168   if (i->fcontents != NULL) free(i->fcontents);
 169   //if (i->fname != NULL) free(i->fname);
 170   free(i);
 171   return EOF;
 172 }
 173
 174
 175 /*
 176  *  yychar() - back up one character
 177  */
 178 static inline void yyunget (int c) {
 179   if (c != EOF) {
 180     if (incp->back_count >= 2) { fprintf(stderr, "yyunget: too much!\n"); abort(); }
 181     incp->back_chars[incp->back_count++] = c;
 182   }
 183 }
 184
 185
 186 /* eat white space */
 187 static int skip_spaces (int c) {
 188   for (;;) {
 189     /* skip past white space */
 190     while (c != EOF && isspace(c)) {
 191       yylval.line = incp->line;
 192       yylval.pos = incp->pos;
 193       c = yychar();
 194     }
 195     /* not a comment? swallow up comment line */
 196     if (c != '#') break;
 197     while ((c = yychar()) != EOF && c != '\n') ;
 198   }
 199   return c;
 200 }
 201
 202
 203 static int digit (int c, int base) {
 204   if (c == EOF) return -1;
 205   if (c >= 'a' && c <= 'z') c -= 32;
 206   if (c < '0' || (c > '9' && c < 'A') || c > 'Z') return -1;
 207   if ((c -= '0') > 9) c -= 7;
 208   if (c >= base) return -1;
 209   return c;
 210 }
 211
 212
 213 /* textlen includes trailing zero */
 214 static void remove_indent (char *text, int textlen, int indent) {
 215   if (indent > 0) {
 216     while (*text) {
 217       char *eol = strchr(text, '\n');
 218       if (eol == NULL) eol = text+textlen-1;
 219       if (eol-text >= indent) {
 220         textlen -= indent;
 221         eol -= indent;
 222         memmove(text, text+indent, textlen);
 223       }
 224       if (!eol[0]) break;
 225       textlen -= eol+1-text;
 226       text = eol+1;
 227     }
 228   }
 229 }
 230
 231
 232 static inline const keyword_t *find_keyword (const char *nbuf, size_t nblen) {
 233   if (nblen > 0) {
 234     for (const keyword_t *k = keywords; k->word; ++k) if (strncmp(k->word, nbuf, nblen) == 0 && k->word[nblen] == 0) return k;
 235   }
 236   return NULL;
 237 }
 238
 239
 240 /*
 241  * yylex() - set yylval to current token; return its type
 242  */
 243
 244 #define PUSH_CHAR(_c)  do { \
 245   if (sbused+1 >= sbsize) { \
 246     int newsz = ((sbused+1)|0x7ff)+1; \
 247     char *nb = realloc(sbuf, newsz); \
 248     if (nb == NULL) { fprintf(stderr, "FATAL: out of memory!\n"); abort(); } \
 249     sbuf = nb; \
 250     sbsize = newsz; \
 251   } \
 252   sbuf[sbused++] = (_c); \
 253 } while (0)
 254
 255 static char *sbuf = NULL;
 256 static int sbsize = 0;
 257 static int sbused;
 258
 259
 260 /* "$(" already scanned and pushed */
 261 /* return char after ")" */
 262 int scan_varaccess (void) {
 263   int c = yychar(), qch = 0, oc;
 264   if (c == EOF) return c;
 265   /* scan variable name */
 266   while (c != EOF && c != '[' && c != ':') {
 267     PUSH_CHAR(c);
 268     oc = c;
 269     c = yychar();
 270     if (oc == ')') return c;
 271     if (oc == '$' && c == '(') { PUSH_CHAR(c); c = scan_varaccess(); }
 272   }
 273   if (c == EOF) return c;
 274   /* scan indexing; 'c' is not pushed */
 275   if (c == '[') {
 276     while (c != EOF && c != ']') {
 277       PUSH_CHAR(c);
 278       oc = c;
 279       c = yychar();
 280       if (oc == ')') return c;
 281       if (oc == '$' && c == '(') { PUSH_CHAR(c); c = scan_varaccess(); }
 282     }
 283     /* find either selector or ')' */
 284     while (c != EOF && c != ':') {
 285       PUSH_CHAR(c);
 286       oc = c;
 287       c = yychar();
 288       if (oc == ')') return c;
 289       if (oc == '$' && c == '(') { PUSH_CHAR(c); c = scan_varaccess(); }
 290     }
 291     if (c == EOF) return c;
 292   }
 293   /* scan selectors; 'c' is not pushed */
 294   while (c != EOF) {
 295     if (qch != '\'' && c == '\\') {
 296       /* screening */
 297       PUSH_CHAR(c);
 298       if ((c = yychar()) == EOF) break;
 299       PUSH_CHAR(c);
 300       c = yychar();
 301       continue;
 302     }
 303     PUSH_CHAR(c);
 304     oc = c;
 305     c = yychar();
 306     if (!qch && (oc == '"' || oc == '\'')) { qch = oc; continue; }
 307     if (!qch && oc == ')') return c;
 308     if (qch != '\'' && oc == '$' && c == '(') {
 309       PUSH_CHAR(c);
 310       c = scan_varaccess();
 311       continue;
 312     }
 313     if (qch && oc == qch) {
 314       if (!(qch == '\'' && c == '\'')) qch = 0;
 315       continue;
 316     }
 317   }
 318   return c;
 319 }
 320
 321
 322 int yylex (void) {
 323   const keyword_t *kw;
 324   int c;
 325   sbused = 0;
 326   yylval.strlit = 0;
 327   if (!incp) goto eof;
 328   yylval.strlit = 0; /* expand this string */
 329   yylval.line = incp->line;
 330   yylval.pos = incp->pos;
 331   yylval.file = incp->fname;
 332   /* get first character (whitespace or of token) */
 333   c = yychar();
 334   if (scan_mode == SCAN_STRING) {
 335     /* if scanning for a string (action's {}'s), look for the closing brace */
 336     /* we handle matching braces, if they match! */
 337     int nest = 1, indent = -1, cind, bol;
 338     /* skip spaces and newline */
 339     while (c != EOF && c != '\n' && isspace(c)) c = yychar();
 340     if (c == '\n') c = yychar();
 341     /* collect string, caclucate indent */
 342     cind = 0;
 343     bol = 1;
 344     while (c != EOF) {
 345       if (c == '{') ++nest;
 346       else if (c == '}' && !--nest) break;
 347       /* indent calculation */
 348       if (c == '\n') {
 349         cind = 0;
 350         bol = 1;
 351       } else if (bol) {
 352         if (isspace(c)) {
 353           ++cind;
 354         } else {
 355           bol = 0;
 356           if (indent < 0 || cind < indent) indent = cind;
 357         }
 358       }
 359       PUSH_CHAR(c);
 360       c = yychar();
 361     }
 362     /* we ate the ending brace -- regurgitate it */
 363     if (c != EOF) yyunget(c);
 364     /* check obvious errors */
 365     if (nest) { yyerror(&yylval, "unmatched {} in action block"); goto eof; }
 366     /* remove trailing newlines and spaces, add one newline */
 367     while (sbused > 0 && isspace(sbuf[sbused-1])) --sbused;
 368     PUSH_CHAR('\n');
 369     PUSH_CHAR(0);
 370     if (indent > 0) {
 371       //fprintf(stderr, "=== %d ===\n%s===\n", indent, sbuf);
 372       remove_indent(sbuf, sbused, indent);
 373       //fprintf(stderr, "--- %d ---\n%s---\n", indent, sbuf);
 374     }
 375     yylval.type = T_STRING;
 376     yylval.string = newstr(sbuf);
 377     yymode(SCAN_NORMAL);
 378   } else {
 379     int keyword = 0, qch = 0;
 380     int n;
 381     c = skip_spaces(c);
 382     /* c now contains the first character of a token */
 383     if (c == EOF) goto eof;
 384     /* special thingy: single-quoted string */
 385     if (c == '\'') {
 386       for (c = yychar(); c != EOF; c = yychar()) {
 387         if (c == '\'') {
 388           /* check for special case: "''" */
 389           if ((c = yychar()) != '\'') {
 390             if (c != EOF && !isspace(c)) yyunget(c);
 391             break;
 392           }
 393         }
 394         PUSH_CHAR(c);
 395       }
 396       PUSH_CHAR(0);
 397       yylval.type = T_ARG;
 398       yylval.strlit = 1; /* don't expand this string */
 399       yylval.string = newstr(sbuf);
 400       goto lexret;
 401     }
 402     /* 'normal' mode */
 403     keyword = (scan_mode == SCAN_NORMAL && isalpha(c)) || (scan_mode == SCAN_PUNCT && !isalnum(c)); /* maybe */
 404     //if (DEBUG_SCAN) printf("mode: %d; char: '%c'; keyword: %d\n", scan_mode, c, keyword);
 405     /* look for white space to delimit word */
 406     /* \ protects next character */
 407     for (; c != EOF; c = yychar()) {
 408       /* check if this is var access */
 409       if (c == '$') {
 410         keyword = 0;
 411         PUSH_CHAR(c);
 412         if ((c = yychar()) == EOF) break;
 413         if (c == '(') {
 414           PUSH_CHAR(c);
 415           c = scan_varaccess();
 416           yyunget(c);
 417           continue;
 418         }
 419       }
 420       /* check for some common bugs */
 421       if (!qch && c == '(') {
 422         int nc = yychar();
 423         yyunget(nc);
 424         if (nc == '$') yywarning_ex("\"($\" -- maybe you want \"$(\" instead?");
 425         if (sbused > 0 && !isalnum(sbuf[sbused-1]) && (isalnum(nc) || nc == '_' || nc == '-')) yywarning_ex("\"(\" -- maybe you want \"$(\" instead?");
 426       }
 427       /* 'c' is not pushed yet */
 428       if (!qch && scan_mode == SCAN_PUNCT) {
 429         /* we are in list, the only possible keywords follows */
 430         if (strchr("{}[];", c) != NULL) {
 431           if (sbused == 0) {
 432             keyword = 1;
 433             PUSH_CHAR(c);
 434             c = ' ';
 435           }
 436           break;
 437         }
 438       }
 439       if (!qch && (isspace(c) || c == '\'')) break;
 440       if (!qch && scan_mode == SCAN_NORMAL && c != '"' && c != '\'' && !isalnum(c)) {
 441         /* check if this char (and possibly next) forms non-alnum token */
 442         PUSH_CHAR(c);
 443         if ((c = yychar()) != EOF) {
 444           /* try 2-char tokens */
 445           PUSH_CHAR(c);
 446           if ((kw = find_keyword(sbuf+sbused-2, 2)) != NULL) {
 447             if (sbused == 2) {
 448               /* wow! token! */
 449               yylval.type = kw->type;
 450               yylval.string = kw->word; /* used by symdump */
 451               goto lexret;
 452             }
 453             yywarning_ex("non-alpha token without whitespace");
 454             /* return this 2 chars */
 455             yyunget(sbuf[--sbused]);
 456             yyunget(sbuf[--sbused]);
 457             c = ' ';
 458             break;
 459           }
 460           /* return one char back */
 461           --sbused;
 462           yyunget(c);
 463         }
 464         /* try 1-char token */
 465         if (sbused > 1 && sbuf[sbused-1] == '=' && isalnum(sbuf[sbused-2])) goto skipkwone;
 466         if (sbused == 1 && sbuf[sbused-1] == '!') {
 467           int nc = yychar();
 468           yyunget(nc);
 469           if (isalnum(nc)) goto skipkwone;
 470         }
 471         if ((kw = find_keyword(sbuf+sbused-1, 1)) != NULL) {
 472           if (sbused == 1) {
 473             /* wow! token! */
 474             yylval.type = kw->type;
 475             yylval.string = kw->word; /* used by symdump */
 476             goto lexret;
 477           }
 478           if (strchr("{}[];", sbuf[sbused-1]) == NULL) yywarning_ex("non-alpha token without whitespace");
 479           /* return this char */
 480           yyunget(sbuf[--sbused]);
 481           c = ' ';
 482           break;
 483         }
 484 skipkwone:
 485         /* pop this char and process it as usual */
 486         c = sbuf[--sbused];
 487       }
 488       /* check for quoting */
 489       if (qch && c == qch) {
 490         qch = 0;
 491         continue;
 492       }
 493       if (!qch && c == '"') {
 494         keyword = 0;
 495         qch = c;
 496         continue;
 497       }
 498       /* screened char? */
 499       if (c == '\\') {
 500         keyword = 0;
 501         if ((c = yychar()) == EOF) break;
 502         if (qch) {
 503           /* in string */
 504           switch (c) {
 505             case 'a': PUSH_CHAR('\a'); break;
 506             case 'b': PUSH_CHAR('\b'); break;
 507             case 'e': PUSH_CHAR('\x1b'); break;
 508             case 'f': PUSH_CHAR('\f'); break;
 509             case 'n': PUSH_CHAR('\n'); break;
 510             case 'r': PUSH_CHAR('\r'); break;
 511             case 't': PUSH_CHAR('\t'); break;
 512             case 'v': PUSH_CHAR('\v'); break;
 513             case 'x':
 514               // first digit
 515               if ((c = yychar()) == EOF) { yyerror(&yylval, "invalid hex escape in quoted string"); goto eof; }
 516               if ((n = digit(c, 16)) < 0) { yyerror(&yylval, "invalid hex escape in quoted string"); goto eof; }
 517               // second digit
 518               if ((c = yychar()) != EOF) {
 519                 int d = digit(c, 16);
 520                 if (d < 0) yyunget(c); else n = (n*16)+d;
 521               }
 522               if (n == 0) { yyerror(&yylval, "invalid hex escape in quoted string"); goto eof; }
 523               PUSH_CHAR(n);
 524               break;
 525             //TODO: add '\uXXXX'?
 526             default:
 527               if (isalnum(c)) { yyerror(&yylval, "invalid escape in quoted string"); goto eof; }
 528               PUSH_CHAR(c);
 529               break;
 530           }
 531         } else {
 532           /* not in string */
 533           PUSH_CHAR(c);
 534         }
 535         continue;
 536       }
 537       /* normal char */
 538       if (scan_mode == SCAN_NORMAL) {
 539         if (keyword && !isalpha(c)) keyword = 0;
 540       } else if (scan_mode == SCAN_PUNCT) {
 541         if (keyword && isalnum(c)) keyword = 0;
 542       }
 543       PUSH_CHAR(c);
 544     }
 545     /* we looked ahead a character -- back up */
 546     /* don't return spaces, they will be skipped on next call anyway */
 547     if (c != EOF && !isspace(c)) yyunget(c);
 548     /* check obvious errors */
 549     if (qch) { yyerror(&yylval, "unmatched \" in string"); goto eof; }
 550     PUSH_CHAR(0);
 551     /*if (DEBUG_SCAN) printf("keyword: %d; str='%s' (%d)\n", keyword, sbuf, sbused);*/
 552     /* scan token table */
 553     yylval.type = T_ARG;
 554     if (keyword && sbused > 0) {
 555       /* find token */
 556       if ((kw = find_keyword(sbuf, sbused-1)) != NULL) {
 557         yylval.type = kw->type;
 558         yylval.string = kw->word; /* used by symdump */
 559       }
 560     }
 561     if (yylval.type == T_ARG) yylval.string = newstr(sbuf);
 562   }
 563 lexret:
 564   if (DEBUG_SCAN) printf("scan %s\n", symdump(&yylval));
 565   return yylval.type;
 566 eof:
 567   yylval.type = 0; /* 0 is EOF for lemon */
 568   return yylval.type;
 569 }
 570
 571 #undef PUSH_CHAR
 572
 573
 574 static const char *symdump (const token_t *s) {
 575   static char *buf = NULL;
 576   static int bufsz = 0;
 577   int nsz;
 578   if (s->type == EOF) return "EOF";
 579   nsz = strlen(s->string)+128;
 580   if (nsz > bufsz) {
 581     char *nb = realloc(buf, nsz);
 582     if (nb == NULL) { fprintf(stderr, "FATAL: out of memory!\n"); abort(); }
 583     buf = nb;
 584     bufsz = nsz;
 585   }
 586   switch (s->type) {
 587     case 0: sprintf(buf, "unknown symbol <%s>", s->string); break;
 588     case T_ARG: sprintf(buf, "argument <%s>", s->string); break;
 589     case T_STRING: sprintf(buf, "string \"%s\"", s->string); break;
 590     default: sprintf(buf, "keyword `%s`", s->string); break;
 591   }
 592   return buf;
 593 }