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Diffstat (limited to 'expand.c')
| -rw-r--r-- | expand.c | 596 |
1 files changed, 596 insertions, 0 deletions
diff --git a/expand.c b/expand.c new file mode 100644 index 0000000..1c87db1 --- /dev/null +++ b/expand.c @@ -0,0 +1,596 @@ +/* Variable expansion functions for GNU Make. +Copyright (C) 1988-2014 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 3 of the License, 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 +this program. If not, see <http://www.gnu.org/licenses/>. */ + +#include "makeint.h" + +#include <assert.h> + +#include "filedef.h" +#include "job.h" +#include "commands.h" +#include "variable.h" +#include "rule.h" + +/* Initially, any errors reported when expanding strings will be reported + against the file where the error appears. */ +const gmk_floc **expanding_var = &reading_file; + +/* 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. + + For efficiency, it's guaranteed that the buffer will always have + VARIABLE_BUFFER_ZONE extra bytes allocated. This allows you to add a few + extra chars without having to call a function. Note you should never use + these bytes unless you're _sure_ you have room (you know when the buffer + length was last checked. */ + +#define VARIABLE_BUFFER_ZONE 5 + +static unsigned int variable_buffer_length; +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 (char *ptr, const char *string, unsigned int length) +{ + register unsigned int newlen = length + (ptr - variable_buffer); + + if ((newlen + VARIABLE_BUFFER_ZONE) > 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 = xrealloc (variable_buffer, variable_buffer_length); + ptr = variable_buffer + offset; + } + + memcpy (ptr, string, length); + return ptr + length; +} + +/* Return a pointer to the beginning of the variable buffer. */ + +static char * +initialize_variable_output (void) +{ + /* If we don't have a variable output buffer yet, get one. */ + + if (variable_buffer == 0) + { + variable_buffer_length = 200; + variable_buffer = xmalloc (variable_buffer_length); + variable_buffer[0] = '\0'; + } + + return variable_buffer; +} + +/* Recursively expand V. The returned string is malloc'd. */ + +static char *allocated_variable_append (const struct variable *v); + +char * +recursively_expand_for_file (struct variable *v, struct file *file) +{ + char *value; + const gmk_floc *this_var; + const gmk_floc **saved_varp; + struct variable_set_list *save = 0; + int set_reading = 0; + + /* Don't install a new location if this location is empty. + This can happen for command-line variables, builtin variables, etc. */ + saved_varp = expanding_var; + if (v->fileinfo.filenm) + { + this_var = &v->fileinfo; + expanding_var = &this_var; + } + + /* If we have no other file-reading context, use the variable's context. */ + if (!reading_file) + { + set_reading = 1; + reading_file = &v->fileinfo; + } + + if (v->expanding) + { + if (!v->exp_count) + /* Expanding V causes infinite recursion. Lose. */ + OS (fatal, *expanding_var, + _("Recursive variable '%s' references itself (eventually)"), + v->name); + --v->exp_count; + } + + if (file) + { + save = current_variable_set_list; + current_variable_set_list = file->variables; + } + + v->expanding = 1; + if (v->append) + value = allocated_variable_append (v); + else + value = allocated_variable_expand (v->value); + v->expanding = 0; + + if (set_reading) + reading_file = 0; + + if (file) + current_variable_set_list = save; + + expanding_var = saved_varp; + + return value; +} + +/* Expand a simple reference to variable NAME, which is LENGTH chars long. */ + +#ifdef __GNUC__ +__inline +#endif +static char * +reference_variable (char *o, const char *name, unsigned int length) +{ + struct variable *v; + char *value; + + v = lookup_variable (name, length); + + if (v == 0) + warn_undefined (name, length); + + /* If there's no variable by that name or it has no value, stop now. */ + if (v == 0 || (*v->value == '\0' && !v->append)) + return o; + + value = (v->recursive ? recursively_expand (v) : v->value); + + o = variable_buffer_output (o, value, strlen (value)); + + if (v->recursive) + free (value); + + return o; +} + +/* Scan STRING for variable references and expansion-function calls. Only + LENGTH bytes of STRING are actually scanned. If LENGTH is -1, scan until + a null byte is found. + + Write the results to LINE, which must point into 'variable_buffer'. If + LINE is NULL, start at the beginning of the buffer. + Return a pointer to LINE, or to the beginning of the buffer if LINE is + NULL. + */ +char * +variable_expand_string (char *line, const char *string, long length) +{ + struct variable *v; + const char *p, *p1; + char *save; + char *o; + unsigned int line_offset; + + if (!line) + line = initialize_variable_output (); + o = line; + line_offset = line - variable_buffer; + + if (length == 0) + { + variable_buffer_output (o, "", 1); + return (variable_buffer); + } + + /* We need a copy of STRING: due to eval, it's possible that it will get + freed as we process it (it might be the value of a variable that's reset + for example). Also having a nil-terminated string is handy. */ + save = length < 0 ? xstrdup (string) : xstrndup (string, length); + p = save; + + 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 = strchr (p, '$'); + + o = variable_buffer_output (o, p, p1 != 0 ? (unsigned int)(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 ${...} is the general case of substitution. */ + { + char openparen = *p; + char closeparen = (openparen == '(') ? ')' : '}'; + const char *begp; + const char *beg = p + 1; + char *op; + char *abeg = NULL; + const char *end, *colon; + + op = o; + begp = p; + if (handle_function (&op, &begp)) + { + o = op; + p = begp; + break; + } + + /* Is there a variable reference inside the parens or braces? + If so, expand it before expanding the entire reference. */ + + end = strchr (beg, closeparen); + if (end == 0) + /* Unterminated variable reference. */ + O (fatal, *expanding_var, _("unterminated variable reference")); + p1 = lindex (beg, end, '$'); + 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) + { + abeg = expand_argument (beg, p); /* Expand the name. */ + beg = abeg; + end = strchr (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) + { + /* This looks like a substitution reference: $(FOO:A=B). */ + const char *subst_beg = colon + 1; + const char *subst_end = lindex (subst_beg, end, '='); + 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 + { + const char *replace_beg = subst_end + 1; + const char *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 the variable is not empty, perform the + substitution. */ + if (v != 0 && *v->value != '\0') + { + char *pattern, *replace, *ppercent, *rpercent; + char *value = (v->recursive + ? recursively_expand (v) + : v->value); + + /* Copy the pattern and the replacement. Add in an + extra % at the beginning to use in case there + isn't one in the pattern. */ + pattern = alloca (subst_end - subst_beg + 2); + *(pattern++) = '%'; + memcpy (pattern, subst_beg, subst_end - subst_beg); + pattern[subst_end - subst_beg] = '\0'; + + replace = alloca (replace_end - replace_beg + 2); + *(replace++) = '%'; + memcpy (replace, replace_beg, + replace_end - replace_beg); + replace[replace_end - replace_beg] = '\0'; + + /* Look for %. Set the percent pointers properly + based on whether we find one or not. */ + ppercent = find_percent (pattern); + if (ppercent) + { + ++ppercent; + rpercent = find_percent (replace); + if (rpercent) + ++rpercent; + } + else + { + ppercent = pattern; + rpercent = replace; + --pattern; + --replace; + } + + o = patsubst_expand_pat (o, value, pattern, replace, + ppercent, rpercent); + + 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); + + free (abeg); + } + break; + + case '\0': + break; + + default: + if (isblank ((unsigned char)p[-1])) + break; + + /* A $ followed by a random char is a variable reference: + $a is equivalent to $(a). */ + o = reference_variable (o, p, 1); + + break; + } + + if (*p == '\0') + break; + + ++p; + } + + free (save); + + variable_buffer_output (o, "", 1); + return (variable_buffer + line_offset); +} + +/* 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 (const char *line) +{ + return variable_expand_string (NULL, line, (long)-1); +} + +/* 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 (const char *str, const char *end) +{ + char *tmp, *alloc = NULL; + char *r; + + if (str == end) + return xstrdup (""); + + if (!end || *end == '\0') + return allocated_variable_expand (str); + + if (end - str + 1 > 1000) + tmp = alloc = xmalloc (end - str + 1); + else + tmp = alloca (end - str + 1); + + memcpy (tmp, str, end - str); + tmp[end - str] = '\0'; + + r = allocated_variable_expand (tmp); + + free (alloc); + + return r; +} + +/* 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 (const char *line, struct file *file) +{ + char *result; + struct variable_set_list *savev; + const gmk_floc *savef; + + if (file == 0) + return variable_expand (line); + + savev = current_variable_set_list; + current_variable_set_list = file->variables; + + savef = reading_file; + if (file->cmds && file->cmds->fileinfo.filenm) + reading_file = &file->cmds->fileinfo; + else + reading_file = 0; + + result = variable_expand (line); + + current_variable_set_list = savev; + reading_file = savef; + + return result; +} + +/* Like allocated_variable_expand, but for += target-specific variables. + First recursively construct the variable value from its appended parts in + any upper variable sets. Then expand the resulting value. */ + +static char * +variable_append (const char *name, unsigned int length, + const struct variable_set_list *set, int local) +{ + const struct variable *v; + char *buf = 0; + /* If this set is local and the next is not a parent, then next is local. */ + int nextlocal = local && set->next_is_parent == 0; + + /* If there's nothing left to check, return the empty buffer. */ + if (!set) + return initialize_variable_output (); + + /* Try to find the variable in this variable set. */ + v = lookup_variable_in_set (name, length, set->set); + + /* If there isn't one, or this one is private, try the set above us. */ + if (!v || (!local && v->private_var)) + return variable_append (name, length, set->next, nextlocal); + + /* If this variable type is append, first get any upper values. + If not, initialize the buffer. */ + if (v->append) + buf = variable_append (name, length, set->next, nextlocal); + else + buf = initialize_variable_output (); + + /* Append this value to the buffer, and return it. + If we already have a value, first add a space. */ + if (buf > variable_buffer) + buf = variable_buffer_output (buf, " ", 1); + + /* Either expand it or copy it, depending. */ + if (! v->recursive) + return variable_buffer_output (buf, v->value, strlen (v->value)); + + buf = variable_expand_string (buf, v->value, strlen (v->value)); + return (buf + strlen (buf)); +} + + +static char * +allocated_variable_append (const struct variable *v) +{ + char *val; + + /* Construct the appended variable value. */ + + char *obuf = variable_buffer; + unsigned int olen = variable_buffer_length; + + variable_buffer = 0; + + val = variable_append (v->name, strlen (v->name), + current_variable_set_list, 1); + variable_buffer_output (val, "", 1); + val = variable_buffer; + + variable_buffer = obuf; + variable_buffer_length = olen; + + return val; +} + +/* 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 (const 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); + + variable_buffer = obuf; + variable_buffer_length = olen; + + return value; +} + +/* Install a new variable_buffer context, returning the current one for + safe-keeping. */ + +void +install_variable_buffer (char **bufp, unsigned int *lenp) +{ + *bufp = variable_buffer; + *lenp = variable_buffer_length; + + variable_buffer = 0; + initialize_variable_output (); +} + +/* Restore a previously-saved variable_buffer setting (free the current one). + */ + +void +restore_variable_buffer (char *buf, unsigned int len) +{ + free (variable_buffer); + + variable_buffer = buf; + variable_buffer_length = len; +} |