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/* Variable expansion functions for GNU Make.
Copyright (C) 1988, 1989, 1991, 1992 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;
}
/* 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 ${...} is the general case of substitution. */
{
char openparen = *p;
char closeparen = (openparen == '(') ? ')' : '}';
register char *beg = p + 1;
char *op, *begp;
char *end;
op = o;
begp = p;
if (handle_function (&op, &begp))
{
o = op;
p = begp;
break;
}
/* Is there a variable reference inside the parens or braces?
If so, expand it before expanding the entire reference. */
p1 = index (beg, closeparen);
if (p1 != 0)
p1 = lindex (beg, p1, '$');
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)
{
char *name = expand_argument (beg, p);
static char start[3] = { '$', }, end[2];
start[1] = openparen;
end[0] = closeparen;
p1 = concat (start, name, end);
free (name);
name = allocated_variable_expand (p1);
o = variable_buffer_output (o, name, strlen (name));
free (name);
break;
}
}
/* This is not a reference to a built-in function and
it does not contain any variable references inside.
There are several things it could be. */
p = index (beg, ':');
if (p != 0 && lindex (beg, p, closeparen) == 0)
{
/* This is a substitution reference: $(FOO:A=B). */
int count;
char *subst_beg, *replace_beg;
unsigned int subst_len, replace_len;
v = lookup_variable (beg, p - beg);
subst_beg = p + 1;
count = 0;
for (p = subst_beg; *p != '\0'; ++p)
{
if (*p == openparen)
++count;
else if (*p == closeparen)
--count;
else if (*p == '=' && count <= 0)
break;
}
if (count > 0)
/* There were unmatched opening parens. */
return initialize_variable_output ();
subst_len = p - subst_beg;
replace_beg = p + 1;
count = 0;
for (p = replace_beg; *p != '\0'; ++p)
{
if (*p == openparen)
++count;
else if (*p == closeparen && --count < 0)
break;
}
if (count > 0)
/* There were unmatched opening parens. */
return initialize_variable_output ();
end = p;
replace_len = p - replace_beg;
if (v != 0 && *v->value != '\0')
{
char *value = (v->recursive ? recursively_expand (v)
: v->value);
if (lindex (subst_beg, subst_beg + subst_len, '%') != 0)
{
p = savestring (subst_beg, subst_len);
p1 = savestring (replace_beg, replace_len);
o = patsubst_expand (o, value, p, p1,
(char *) 0, (char *) 0);
free (p);
free (p1);
}
else
o = subst_expand (o, value, subst_beg, replace_beg,
subst_len, replace_len, 0, 1);
if (v->recursive)
free (value);
}
}
/* No, this must be an ordinary variable reference. */
else
{
/* Look up the value of the variable. */
end = index (beg, closeparen);
if (end == 0)
return initialize_variable_output ();
v = lookup_variable (beg, end - beg);
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);
}
}
/* Advance p past the variable reference to resume scan. */
p = end;
}
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 = savestring (str, end - str);
char *value = allocated_variable_expand (tmp);
free (tmp);
return value;
}
/* 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;
}
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