94 lines
2 KiB
C
94 lines
2 KiB
C
/* SPDX-License-Identifier: LGPL-2.1-or-later */
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#include <errno.h>
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#include <stddef.h>
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#include <stdlib.h>
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#include "alloc-util.h"
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#include "macro.h"
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#include "replace-var.h"
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#include "string-util.h"
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/*
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* Generic infrastructure for replacing @FOO@ style variables in
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* strings. Will call a callback for each replacement.
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*/
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static int get_variable(const char *b, char **r) {
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size_t k;
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char *t;
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assert(b);
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assert(r);
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if (*b != '@')
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return 0;
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k = strspn(b + 1, UPPERCASE_LETTERS "_");
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if (k <= 0 || b[k+1] != '@')
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return 0;
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t = strndup(b + 1, k);
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if (!t)
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return -ENOMEM;
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*r = t;
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return 1;
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}
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char *replace_var(const char *text, char *(*lookup)(const char *variable, void *userdata), void *userdata) {
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char *r, *t;
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const char *f;
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size_t l;
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assert(text);
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assert(lookup);
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l = strlen(text);
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r = new(char, l+1);
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if (!r)
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return NULL;
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f = text;
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t = r;
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while (*f) {
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_cleanup_free_ char *v = NULL, *n = NULL;
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char *a;
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int k;
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size_t skip, d, nl;
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k = get_variable(f, &v);
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if (k < 0)
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goto oom;
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if (k == 0) {
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*(t++) = *(f++);
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continue;
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}
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n = lookup(v, userdata);
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if (!n)
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goto oom;
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skip = strlen(v) + 2;
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d = t - r;
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nl = l - skip + strlen(n);
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a = realloc(r, nl + 1);
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if (!a)
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goto oom;
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l = nl;
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r = a;
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t = r + d;
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t = stpcpy(t, n);
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f += skip;
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}
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*t = 0;
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return r;
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oom:
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return mfree(r);
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}
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