aboutsummaryrefslogtreecommitdiff
path: root/expand.c
blob: 7348fb261763ddc0bd19c6462f5442b886de2ecf (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
/* Variable expansion functions for GNU Make.
Copyright (C) 1988, 89, 91, 92, 93, 95 Free Software Foundation, Inc.
This file is part of GNU Make.

GNU Make is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU Make is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Make; see the file COPYING.  If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */

#include "make.h"
#include "commands.h"
#include "file.h"
#include "variable.h"

/* The next two describe the variable output buffer.
   This buffer is used to hold the variable-expansion of a line of the
   makefile.  It is made bigger with realloc whenever it is too small.
   variable_buffer_length is the size currently allocated.
   variable_buffer is the address of the buffer.  */

static unsigned int variable_buffer_length;
static char *variable_buffer;

/* Subroutine of variable_expand and friends:
   The text to add is LENGTH chars starting at STRING to the variable_buffer.
   The text is added to the buffer at PTR, and the updated pointer into
   the buffer is returned as the value.  Thus, the value returned by
   each call to variable_buffer_output should be the first argument to
   the following call.  */

char *
variable_buffer_output (ptr, string, length)
     char *ptr, *string;
     unsigned int length;
{
  register unsigned int newlen = length + (ptr - variable_buffer);

  if (newlen > variable_buffer_length)
    {
      unsigned int offset = ptr - variable_buffer;
      variable_buffer_length = (newlen + 100 > 2 * variable_buffer_length
				? newlen + 100
				: 2 * variable_buffer_length);
      variable_buffer = (char *) xrealloc (variable_buffer,
					   variable_buffer_length);
      ptr = variable_buffer + offset;
    }

  bcopy (string, ptr, length);
  return ptr + length;
}

/* Return a pointer to the beginning of the variable buffer.  */

static char *
initialize_variable_output ()
{
  /* If we don't have a variable output buffer yet, get one.  */

  if (variable_buffer == 0)
    {
      variable_buffer_length = 200;
      variable_buffer = (char *) xmalloc (variable_buffer_length);
      variable_buffer[0] = '\0';
    }

  return variable_buffer;
}

/* Recursively expand V.  The returned string is malloc'd.  */

char *
recursively_expand (v)
     register struct variable *v;
{
  char *value;

  if (v->expanding)
    {
      /* Expanding V causes infinite recursion.  Lose.  */
      if (reading_filename == 0)
	fatal ("Recursive variable `%s' references itself (eventually)",
	       v->name);
      else
	makefile_fatal
	  (reading_filename, *reading_lineno_ptr, 
	   "Recursive variable `%s' references itself (eventually)",
	   v->name);
    }

  v->expanding = 1;
  value = allocated_variable_expand (v->value);
  v->expanding = 0;

  return value;
}

/* Warn that NAME is an undefined variable.  */

#ifdef __GNUC__
__inline
#endif
static void
warn_undefined (name, length)
     char *name;
     unsigned int length;
{
  if (warn_undefined_variables_flag)
    {
      static const char warnmsg[] = "warning: undefined variable `%.*s'";
      if (reading_filename != 0)
	makefile_error (reading_filename, *reading_lineno_ptr,
			warnmsg, length, name);
      else
	error (warnmsg, length, name);
    }
}

/* Expand a simple reference to variable NAME, which is LENGTH chars long.  */

#ifdef __GNUC__
__inline
#endif
static char *
reference_variable (o, name, length)
     char *o;
     char *name;
     unsigned int length;
{
  register struct variable *v = lookup_variable (name, length);

  if (v == 0)
    warn_undefined (name, length);

  if (v != 0 && *v->value != '\0')
    {
      char *value = (v->recursive ? recursively_expand (v) : v->value);
      o = variable_buffer_output (o, value, strlen (value));
      if (v->recursive)
	free (value);
    }

  return o;
}

/* Scan LINE for variable references and expansion-function calls.
   Build in `variable_buffer' the result of expanding the references and calls.
   Return the address of the resulting string, which is null-terminated
   and is valid only until the next time this function is called.  */

char *
variable_expand (line)
     register char *line;
{
  register struct variable *v;
  register char *p, *o, *p1;

  p = line;
  o = initialize_variable_output ();

  while (1)
    {
      /* Copy all following uninteresting chars all at once to the
         variable output buffer, and skip them.  Uninteresting chars end
	 at the next $ or the end of the input.  */

      p1 = index (p, '$');

      o = variable_buffer_output (o, p, p1 != 0 ? p1 - p : strlen (p) + 1);

      if (p1 == 0)
	break;
      p = p1 + 1;

      /* Dispatch on the char that follows the $.  */

      switch (*p)
	{
	case '$':
	  /* $$ seen means output one $ to the variable output buffer.  */
	  o = variable_buffer_output (o, p, 1);
	  break;

	case '(':
	case '{':
	  /* $(...) or ${...} is the general case of substitution.  */
	  {
	    char openparen = *p;
	    char closeparen = (openparen == '(') ? ')' : '}';
	    register char *beg = p + 1;
	    int free_beg = 0;
	    char *op, *begp;
	    char *end, *colon;

	    op = o;
	    begp = p;
	    if (handle_function (&op, &begp))
	      {
		o = op;
		p = begp;
		break;
	      }

	    /* Is there a variable reference inside the parens or braces?
	       If so, expand it before expanding the entire reference.  */

	    end = index (beg, closeparen);
	    if (end == 0)
	      {
		/* Unterminated variable reference.  */
		if (reading_filename != 0)
		  makefile_fatal (reading_filename, *reading_lineno_ptr,
				  "unterminated variable reference");
		else
		  fatal ("unterminated variable reference");
	      }
	    p1 = lindex (beg, end, '$');
	    if (p1 != 0)
	      {
		/* BEG now points past the opening paren or brace.
		   Count parens or braces until it is matched.  */
		int count = 0;
		for (p = beg; *p != '\0'; ++p)
		  {
		    if (*p == openparen)
		      ++count;
		    else if (*p == closeparen && --count < 0)
		      break;
		  }
		/* If COUNT is >= 0, there were unmatched opening parens
		   or braces, so we go to the simple case of a variable name
		   such as `$($(a)'.  */
		if (count < 0)
		  {
		    beg = expand_argument (beg, p); /* Expand the name.  */
		    free_beg = 1; /* Remember to free BEG when finished.  */
		    end = index (beg, '\0');
		  }
	      }
	    else
	      /* Advance P to the end of this reference.  After we are
                 finished expanding this one, P will be incremented to
                 continue the scan.  */
	      p = end;

	    /* This is not a reference to a built-in function and
	       any variable references inside are now expanded.
	       Is the resultant text a substitution reference?  */

	    colon = lindex (beg, end, ':');
	    if (colon != 0)
	      {
		/* This looks like a substitution reference: $(FOO:A=B).  */
		char *subst_beg, *subst_end, *replace_beg, *replace_end;

		subst_beg = colon + 1;
		subst_end = index (subst_beg, '=');
		if (subst_end == 0)
		  /* There is no = in sight.  Punt on the substitution
		     reference and treat this as a variable name containing
		     a colon, in the code below.  */
		  colon = 0;
		else
		  {
		    replace_beg = subst_end + 1;
		    replace_end = end;

		    /* Extract the variable name before the colon
		       and look up that variable.  */
		    v = lookup_variable (beg, colon - beg);
		    if (v == 0)
		      warn_undefined (beg, colon - beg);

		    if (v != 0 && *v->value != '\0')
		      {
			char *value = (v->recursive ? recursively_expand (v)
				       : v->value);
			char *pattern, *percent;
			if (free_beg)
			  {
			    *subst_end = '\0';
			    pattern = subst_beg;
			  }
			else
			  {
			    pattern = (char *) alloca (subst_end - subst_beg
						       + 1);
			    bcopy (subst_beg, pattern, subst_end - subst_beg);
			    pattern[subst_end - subst_beg] = '\0';
			  }
			percent = find_percent (pattern);
			if (percent != 0)
			  {
			    char *replace;
			    if (free_beg)
			      {
				*replace_end = '\0';
				replace = replace_beg;
			      }
			    else
			      {
				replace = (char *) alloca (replace_end
							   - replace_beg
							   + 1);
				bcopy (replace_beg, replace,
				       replace_end - replace_beg);
				replace[replace_end - replace_beg] = '\0';
			      }
			    
			    o = patsubst_expand (o, value, pattern, replace,
						 percent, (char *) 0);
			  }
			else
			  o = subst_expand (o, value,
					    pattern, replace_beg,
					    strlen (pattern),
					    end - replace_beg,
					    0, 1);
			if (v->recursive)
			  free (value);
		      }
		  }
	      }

	    if (colon == 0)
	      /* This is an ordinary variable reference.
		 Look up the value of the variable.  */
		o = reference_variable (o, beg, end - beg);

	  if (free_beg)
	    free (beg);
	  }
	  break;

	case '\0':
	  break;

	default:
	  if (isblank (p[-1]))
	    break;

	  /* A $ followed by a random char is a variable reference:
	     $a is equivalent to $(a).  */
	  {
	    /* We could do the expanding here, but this way
	       avoids code repetition at a small performance cost.  */
	    char name[5];
	    name[0] = '$';
	    name[1] = '(';
	    name[2] = *p;
	    name[3] = ')';
	    name[4] = '\0';
	    p1 = allocated_variable_expand (name);
	    o = variable_buffer_output (o, p1, strlen (p1));
	    free (p1);
	  }

	  break;
	}      

      if (*p == '\0')
	break;
      else
	++p;
    }

  (void) variable_buffer_output (o, "", 1);
  return initialize_variable_output ();
}

/* Expand an argument for an expansion function.
   The text starting at STR and ending at END is variable-expanded
   into a null-terminated string that is returned as the value.
   This is done without clobbering `variable_buffer' or the current
   variable-expansion that is in progress.  */

char *
expand_argument (str, end)
     char *str, *end;
{
  char *tmp;

  if (*end == '\0')
    tmp = str;
  else
    {
      tmp = (char *) alloca (end - str + 1);
      bcopy (str, tmp, end - str);
      tmp[end - str] = '\0';
    }

  return allocated_variable_expand (tmp);
}

/* Expand LINE for FILE.  Error messages refer to the file and line where
   FILE's commands were found.  Expansion uses FILE's variable set list.  */

char *
variable_expand_for_file (line, file)
     char *line;
     register struct file *file;
{
  char *result;
  struct variable_set_list *save;

  if (file == 0)
    return variable_expand (line);

  save = current_variable_set_list;
  current_variable_set_list = file->variables;
  reading_filename = file->cmds->filename;
  reading_lineno_ptr = &file->cmds->lineno;
  result = variable_expand (line);
  current_variable_set_list = save;
  reading_filename = 0;
  reading_lineno_ptr = 0;

  return result;
}

/* Like variable_expand_for_file, but the returned string is malloc'd.
   This function is called a lot.  It wants to be efficient.  */

char *
allocated_variable_expand_for_file (line, file)
     char *line;
     struct file *file;
{
  char *value;

  char *obuf = variable_buffer;
  unsigned int olen = variable_buffer_length;

  variable_buffer = 0;

  value = variable_expand_for_file (line, file);

#if 0
  /* Waste a little memory and save time.  */
  value = xrealloc (value, strlen (value))
#endif

  variable_buffer = obuf;
  variable_buffer_length = olen;

  return value;
}