shared: add API for replacing @FOO@ style variables in strings

This commit is contained in:
Lennart Poettering 2012-11-14 22:20:17 +01:00
parent 409bc9c33e
commit 6e6fb527f9
5 changed files with 193 additions and 2 deletions

1
.gitignore vendored
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@ -1,3 +1,4 @@
/test-replace-var
/test-journal-enum
/test-sleep
/localectl

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@ -798,6 +798,8 @@ libsystemd_shared_la_SOURCES = \
src/shared/spawn-ask-password-agent.h \
src/shared/specifier.c \
src/shared/specifier.h \
src/shared/replace-var.c \
src/shared/replace-var.h \
src/shared/spawn-polkit-agent.c \
src/shared/spawn-polkit-agent.h \
src/shared/hwclock.c \
@ -1182,7 +1184,8 @@ noinst_PROGRAMS += \
test-log \
test-unit-file \
test-date \
test-sleep
test-sleep \
test-replace-var
TESTS += \
test-job-type \
@ -1191,7 +1194,8 @@ TESTS += \
test-unit-name \
test-unit-file \
test-date \
test-sleep
test-sleep \
test-replace-var
test_engine_SOURCES = \
src/test/test-engine.c
@ -1265,6 +1269,12 @@ test_sleep_SOURCES = \
test_sleep_LDADD = \
libsystemd-core.la
test_replace_var_SOURCES = \
src/test/test-replace-var.c
test_replace_var_LDADD = \
libsystemd-shared.la
test_daemon_SOURCES = \
src/test/test-daemon.c

110
src/shared/replace-var.c Normal file
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@ -0,0 +1,110 @@
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2012 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <string.h>
#include "macro.h"
#include "util.h"
#include "replace-var.h"
/*
* Generic infrastructure for replacing @FOO@ style variables in
* strings. Will call a callback for each replacement.
*/
static int get_variable(const char *b, char **r) {
size_t k;
char *t;
assert(b);
assert(r);
if (*b != '@')
return 0;
k = strspn(b + 1, "ABCDEFGHIJKLMNOPQRSTUVWXYZ_");
if (k <= 0 || b[k+1] != '@')
return 0;
t = strndup(b + 1, k);
if (!t)
return -ENOMEM;
*r = t;
return 1;
}
char *replace_var(const char *text, char *(*lookup)(const char *variable, void*userdata), void *userdata) {
char *r, *t;
const char *f;
size_t l;
assert(text);
assert(lookup);
l = strlen(text);
r = new(char, l+1);
if (!r)
return NULL;
f = text;
t = r;
while (*f) {
_cleanup_free_ char *v = NULL, *n = NULL;
char *a;
int k;
size_t skip, d, nl;
k = get_variable(f, &v);
if (k < 0)
goto oom;
if (k == 0) {
*(t++) = *(f++);
continue;
}
n = lookup(v, userdata);
if (!n)
goto oom;
skip = strlen(v) + 2;
d = t - r;
nl = l - skip + strlen(n);
a = realloc(r, nl + 1);
if (!a)
goto oom;
l = nl;
r = a;
t = r + d;
t = stpcpy(t, n);
f += skip;
}
*t = 0;
return r;
oom:
free(r);
return NULL;
}

24
src/shared/replace-var.h Normal file
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@ -0,0 +1,24 @@
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
#pragma once
/***
This file is part of systemd.
Copyright 2012 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
char *replace_var(const char *text, char *(*lookup)(const char *variable, void*userdata), void *userdata);

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@ -0,0 +1,46 @@
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2012 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <string.h>
#include "util.h"
#include "macro.h"
#include "replace-var.h"
static char *lookup(const char *variable, void *userdata) {
return strjoin("<<<", variable, ">>>", NULL);
}
int main(int argc, char *argv[]) {
char *r;
assert_se(r = replace_var("@@@foobar@xyz@HALLO@foobar@test@@testtest@TEST@...@@@", lookup, NULL));
puts(r);
assert_se(streq(r, "@@@foobar@xyz<<<HALLO>>>foobar@test@@testtest<<<TEST>>>...@@@"));
free(r);
assert_se(r = strreplace("XYZFFFFXYZFFFFXYZ", "XYZ", "ABC"));
puts(r);
assert_se(streq(r, "ABCFFFFABCFFFFABC"));
free(r);
return 0;
}