src/expand.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  * expand.c - expand a buffer, given variable values
   8  *
   9  * External routines:
  10  *
  11  *  var_expand() - variable-expand input string into list of strings
  12  *
  13  * Internal routines:
  14  *
  15  *  var_edit_parse() - parse : modifiers into PATHNAME structure
  16  *  var_edit_file() - copy input target name to output, modifying filename
  17  *  var_edit_shift() - do upshift/downshift mods
  18  *
  19  * 01/25/94 (seiwald) - $(X)$(UNDEF) was expanding like plain $(X)
  20  * 04/13/94 (seiwald) - added shorthand L0 for null list pointer
  21  * 01/20/00 (seiwald) - Upgraded from K&R to ANSI C
  22  * 01/11/01 (seiwald) - added support for :E=emptyvalue, :J=joinval
  23  * 01/13/01 (seiwald) - :UDJE work on non-filename strings
  24  * 02/19/01 (seiwald) - make $($(var):J=x) join multiple values of var
  25  * 01/25/02 (seiwald) - fixed broken $(v[1-]), by ian godin
  26  * 10/22/02 (seiwald) - list_new() now does its own newstr()/copystr()
  27  * 11/04/02 (seiwald) - const-ing for string literals
  28  * 12/30/02 (armstrong) - fix out-of-bounds access in var_expand()
  29  */
  30 #include "jam.h"
  31 #include "lists.h"
  32 #include "variable.h"
  33 #include "expand.h"
  34 #include "pathsys.h"
  35 #include "newstr.h"
  36
  37
  38 typedef struct {
  39   PATHNAME f; /* :GDBSMR -- pieces */
  40   char parent; /* :P -- go to parent directory */
  41   char filemods; /* one of the above applied */
  42   char downshift; /* :L -- downshift result */
  43   char upshift; /* :U -- upshift result */
  44   char quote; /* :Q -- quote */
  45   PATHPART empty; /* :E -- default for empties */
  46   PATHPART join; /* :J -- join list with char */
  47 } VAR_EDITS;
  48
  49
  50 static void var_edit_parse (char *mods, VAR_EDITS *edits);
  51 static void var_edit_file (const char *in, char *out, VAR_EDITS *edits);
  52 static void var_edit_shift (char *out, VAR_EDITS *edits);
  53 static void var_edit_quote (char *out);
  54
  55 #define MAGIC_COLON  '\001'
  56 #define MAGIC_LEFT   '\002'
  57 #define MAGIC_RIGHT  '\003'
  58
  59
  60 /*
  61  * var_expand() - variable-expand input string into list of strings
  62  *
  63  * Would just copy input to output, performing variable expansion,
  64  * except that since variables can contain multiple values the result
  65  * of variable expansion may contain multiple values (a list).  Properly
  66  * performs "product" operations that occur in "$(var1)xxx$(var2)" or
  67  * even "$($(var2))".
  68  *
  69  * Returns a newly created list.
  70  */
  71 LIST *var_expand (LIST *l, const char *in, const char *end, LOL *lol, int cancopyin) {
  72   char out_buf[MAXSYM];
  73   char *out = out_buf;
  74   const char *inp = in;
  75   char *ov; /* for temp copy of variable in outbuf */
  76   int depth;
  77   //
  78   if (DEBUG_VAREXP) printf("expand '%.*s'\n", (int)(end-in), in);
  79   /* this gets alot of cases: $(<) and $(>) */
  80   if (end-in == 4 && in[0] == '$' && in[1] == '(' && in[3] == ')') {
  81     switch (in[2]) {
  82       case '1': case '<': return list_copy(l, lol_get(lol, 0));
  83       case '2': case '>': return list_copy(l, lol_get(lol, 1));
  84     }
  85   }
  86   /* just try simple copy of in to out */
  87   while (in < end) {
  88     if ((*out++ = *in++) == '$' && *in == '(') goto expand;
  89   }
  90   /* no variables expanded - just add copy of input string to list */
  91   /* cancopyin is an optimization: if the input was already a list */
  92   /* item, we can use the copystr() to put it on the new list, */
  93   /* otherwise, we use the slower newstr() */
  94   *out = '\0';
  95   if (cancopyin) return list_new(l, inp, 1); else return list_new(l, out_buf, 0);
  96 expand:
  97   /*
  98    * Input so far (ignore blanks):
  99    *
 100    *  stuff-in-outbuf $(variable) remainder
 101    *       ^               ^
 102    *       in        end
 103    * Output so far:
 104    *
 105    *  stuff-in-outbuf $
 106    *  ^          ^
 107    *  out_buf          out
 108    *
 109    *
 110    * We just copied the $ of $(...), so back up one on the output.
 111    * We now find the matching close paren, copying the variable and
 112    * modifiers between the $(and) temporarily into out_buf, so that
 113    * we can replace :'s with MAGIC_COLON.  This is necessary to avoid
 114    * being confused by modifier values that are variables containing
 115    * :'s.  Ugly.
 116    */
 117   depth = 1;
 118   --out; ++in;
 119   ov = out;
 120   while (in < end && depth) {
 121     switch (*ov++ = *in++) {
 122       case '(': ++depth; break;
 123       case ')': --depth; break;
 124       case ':': ov[-1] = MAGIC_COLON; break;
 125       case '[': ov[-1] = MAGIC_LEFT; break;
 126       case ']': ov[-1] = MAGIC_RIGHT; break;
 127     }
 128   }
 129   /* Copied) - back up. */
 130   --ov;
 131   /*
 132    * Input so far (ignore blanks):
 133    *
 134    *  stuff-in-outbuf $(variable) remainder
 135    *                  ^        ^
 136    *                  in       end
 137    * Output so far:
 138    *
 139    *  stuff-in-outbuf variable
 140    *  ^         ^       ^
 141    *  out_buf         out ov
 142    *
 143    * Later we will overwrite 'variable' in out_buf, but we'll be
 144    * done with it by then.  'variable' may be a multi-element list,
 145    * so may each value for '$(variable element)', and so may 'remainder'.
 146    * Thus we produce a product of three lists.
 147    */
 148   {
 149     LIST *variables = 0;
 150     LIST *remainder = 0;
 151     LIST *vars;
 152     //
 153     /* recursively expand variable name & rest of input */
 154     if (out < ov) variables = var_expand(L0, out, ov, lol, 0);
 155     if (in < end) remainder = var_expand(L0, in, end, lol, 0);
 156     /* now produce the result chain */
 157     /* for each variable name */
 158     for (vars = variables; vars; vars = list_next(vars)) {
 159       LIST *value, *evalue = 0;
 160       char *colon;
 161       char *bracket;
 162       char varname[MAXSYM];
 163       int sub1 = 0, sub2 = -1;
 164       VAR_EDITS edits;
 165       //
 166       /* look for a : modifier in the variable name */
 167       /* must copy into varname so we can modify it */
 168       strcpy(varname, vars->string);
 169       if ((colon = strchr(varname, MAGIC_COLON))) {
 170         *colon = '\0';
 171         var_edit_parse(colon+1, &edits);
 172       }
 173       /* look for [x-y] subscripting */
 174       /* sub1 is x (0 default) */
 175       /* sub2 is length (-1 means forever) */
 176       if ((bracket = strchr(varname, MAGIC_LEFT))) {
 177         char *dash;
 178         //
 179         if ((dash = strchr(bracket+1, '-'))) *dash = '\0';
 180         sub1 = atoi(bracket+1)-1;
 181         if (!dash) sub2 = 1;
 182         else if (!dash[1] || dash[1] == MAGIC_RIGHT) sub2 = -1;
 183         else sub2 = atoi(dash+1)-sub1;
 184         *bracket = '\0';
 185       }
 186       /* get variable value, specially handling $(<), $(>), $(n) */
 187       if (varname[0] == '<' && !varname[1]) value = lol_get(lol, 0);
 188       else if (varname[0] == '>' && !varname[1]) value = lol_get(lol, 1);
 189       else if (varname[0] >= '1' && varname[0] <= '9' && !varname[1]) value = lol_get(lol, varname[0]-'1');
 190       else value = var_get(varname);
 191       /* the fast path: $(x) - just copy the variable value */
 192       /* this is only an optimization */
 193       if (out == out_buf && !bracket && !colon && in == end) {
 194         l = list_copy(l, value);
 195         continue;
 196       }
 197       /* handle start subscript */
 198       while (sub1 > 0 && value) {
 199         --sub1;
 200         value = list_next(value);
 201       }
 202       /* empty w/ :E=default? */
 203       if (!value && colon && edits.empty.ptr) evalue = value = list_new(L0, edits.empty.ptr, 0);
 204       /* for each variable value */
 205       for (; value; value = list_next(value)) {
 206         LIST *rem;
 207         char *out1;
 208         //
 209         /* handle end subscript (length actually) */
 210         if (sub2 >= 0 && --sub2 < 0) break;
 211         /* apply : mods, if present */
 212         if (colon && edits.filemods) var_edit_file(value->string, out, &edits); else strcpy(out, value->string);
 213         if (colon && (edits.upshift || edits.downshift)) var_edit_shift(out, &edits);
 214         if (colon && edits.quote) var_edit_quote(out);
 215         /* handle :J=joinval */
 216         /* if we have more values for this var, just */
 217         /* keep appending them (with the join value) */
 218         /* rather than creating separate LIST elements */
 219         if (colon && edits.join.ptr && (list_next(value) || list_next(vars))) {
 220           out += strlen(out);
 221           strcpy(out, edits.join.ptr);
 222           out += strlen(out);
 223           continue;
 224         }
 225         /* if no remainder, append result to output chain */
 226         if (in == end) { l = list_new(l, out_buf, 0); continue; }
 227         /* for each remainder, append the complete string to the output chain */
 228         /* remember the end of the variable expansion so we can just tack on each instance of 'remainder' */
 229         out1 = out+strlen(out);
 230         for (rem = remainder; rem; rem = list_next(rem)) {
 231           strcpy(out1, rem->string);
 232           l = list_new(l, out_buf, 0);
 233         }
 234       }
 235       /* toss used empty */
 236       if (evalue) list_free(evalue);
 237     } /* for */
 238     /* variables & remainder were gifts from var_expand and must be freed */
 239     if (variables) list_free(variables);
 240     if (remainder) list_free(remainder);
 241     if (DEBUG_VAREXP) {
 242       printf("expanded to ");
 243       list_print(l);
 244       printf("\n");
 245     }
 246     return l;
 247   }
 248 }
 249
 250
 251 /*
 252  * var_edit_parse() - parse : modifiers into PATHNAME structure
 253  *
 254  * The : modifiers in a $(varname:modifier) currently support replacing
 255  * or omitting elements of a filename, and so they are parsed into a
 256  * PATHNAME structure (which contains pointers into the original string).
 257  *
 258  * Modifiers of the form "X=value" replace the component X with
 259  * the given value.  Modifiers without the "=value" cause everything
 260  * but the component X to be omitted.  X is one of:
 261  *
 262  *  G <grist>
 263  *  D directory name
 264  *  B base name
 265  *  S .suffix
 266  *  M (member)
 267  *  R root directory - prepended to whole path
 268  *
 269  * This routine sets:
 270  *
 271  *  f->f_xxx.ptr = 0
 272  *  f->f_xxx.len = 0
 273  *    -> leave the original component xxx
 274  *
 275  *  f->f_xxx.ptr = string
 276  *  f->f_xxx.len = strlen(string)
 277  *    -> replace component xxx with string
 278  *
 279  *  f->f_xxx.ptr = ""
 280  *  f->f_xxx.len = 0
 281  *    -> omit component xxx
 282  *
 283  * var_edit_file() below and path_build() obligingly follow this convention.
 284  */
 285 static void var_edit_parse (char *mods, VAR_EDITS *edits) {
 286   int havezeroed = 0;
 287   //
 288   memset((char *)edits, 0, sizeof(*edits));
 289   while (*mods) {
 290     char *p;
 291     PATHPART *fp;
 292     //
 293     switch (*mods++) {
 294       case 'L': edits->downshift = 1; continue;
 295       case 'U': edits->upshift = 1; continue;
 296       case 'Q': edits->quote = 1; continue;
 297       case 'P': edits->parent = edits->filemods = 1; continue;
 298       case 'E': fp = &edits->empty; goto strval;
 299       case 'J': fp = &edits->join; goto strval;
 300       case 'G': fp = &edits->f.f_grist; goto fileval;
 301       case 'R': fp = &edits->f.f_root; goto fileval;
 302       case 'D': fp = &edits->f.f_dir; goto fileval;
 303       case 'B': fp = &edits->f.f_base; goto fileval;
 304       case 'S': fp = &edits->f.f_suffix; goto fileval;
 305       case 'M': fp = &edits->f.f_member; goto fileval;
 306       default: return; /* should complain, but so what... */
 307     }
 308 fileval:
 309     /* handle :CHARS, where each char (without a following =) selects a particular file path element */
 310     /* on the first such char, we deselect all others (by setting ptr = "", len = 0) */
 311     /* and for each char we select that element (by setting ptr = 0) */
 312     edits->filemods = 1;
 313     if (*mods != '=') {
 314       if (!havezeroed++) {
 315         int i;
 316         //
 317         for (i = 0; i < 6; i++) {
 318           edits->f.part[i].len = 0;
 319           edits->f.part[i].ptr = "";
 320         }
 321       }
 322       fp->ptr = 0;
 323       continue;
 324     }
 325 strval:
 326     /* handle :X=value, or :X */
 327     if (*mods != '=') {
 328       fp->ptr = "";
 329       fp->len = 0;
 330     } else {
 331       //FIXME: ugly hack to allow things like $(>[2:S=.tiles]) (they are bad, but...)
 332       p = mods;
 333       while (*p && *p != MAGIC_COLON && *p != MAGIC_LEFT && *p != MAGIC_RIGHT) ++p;
 334       if (*p) {
 335         *p = 0;
 336         fp->ptr = ++mods;
 337         fp->len = p-mods;
 338         mods = p+1;
 339       } else {
 340         fp->ptr = ++mods;
 341         fp->len = strlen(fp->ptr);
 342         mods += fp->len;
 343         //fprintf(stderr, "len=%d [", fp->len); fwrite(fp->ptr, 1, fp->len, stderr); fprintf(stderr, "]\n");
 344       }
 345     }
 346   }
 347 }
 348
 349
 350 /*
 351  * var_edit_file() - copy input target name to output, modifying filename
 352  */
 353 static void var_edit_file (const char *in, char *out, VAR_EDITS *edits) {
 354   PATHNAME pathname;
 355   //
 356   /* parse apart original filename, putting parts into "pathname" */
 357   path_parse(in, &pathname);
 358   /* replace any pathname with edits->f */
 359   if (edits->f.f_grist.ptr) pathname.f_grist = edits->f.f_grist;
 360   if (edits->f.f_root.ptr) pathname.f_root = edits->f.f_root;
 361   if (edits->f.f_dir.ptr) pathname.f_dir = edits->f.f_dir;
 362   if (edits->f.f_base.ptr) pathname.f_base = edits->f.f_base;
 363   if (edits->f.f_suffix.ptr) pathname.f_suffix = edits->f.f_suffix;
 364   if (edits->f.f_member.ptr) pathname.f_member = edits->f.f_member;
 365   /* if requested, modify pathname to point to parent */
 366   if (edits->parent) path_parent(&pathname);
 367   /* put filename back together */
 368   path_build(&pathname, out, 0);
 369 }
 370
 371
 372 /*
 373  * var_edit_shift() - do upshift/downshift mods
 374  */
 375 static void var_edit_shift (char *out, VAR_EDITS *edits) {
 376   /* handle upshifting, downshifting now */
 377   if (edits->upshift) {
 378     for(; *out; ++out) *out = toupper(*out);
 379   } else if (edits->downshift) {
 380     for(; *out; ++out) *out = tolower(*out);
 381   }
 382 }
 383
 384
 385 static int needToScreen (char ch) {
 386   unsigned char uch = (unsigned char)ch;
 387   if (!uch) return 0;
 388   if (uch <= '*' || uch == '`' ||
 389       (uch >= ';' && uch <= '<') ||
 390       (uch >= '>' && uch <= '?') ||
 391       (uch >= '[' && uch <= ']') ||
 392       (uch >= '{' && uch <= '}')) return 1;
 393   return 0;
 394 }
 395
 396
 397 static void var_edit_quote (char *out) {
 398   /* handle quoting now */
 399   int count;
 400   char *p = out;
 401   char *q;
 402   //
 403   count = 0;
 404   for (p = out; *p; ++p) if (needToScreen(*p)) ++count;
 405   q = p+count;
 406   for (; p >= out;) {
 407     if (needToScreen(*p)) {
 408       *q-- = *p--;
 409       *q-- = '\\';
 410     } else {
 411       *q-- = *p--;
 412     }
 413   }
 414 }