git/interpolate.c
Michal Vitecek 55246aac67 Don't use "<unknown>" for placeholders and suppress printing of empty user formats.
This changes the interporate() to replace entries with NULL values
by the empty string, and uses it to interpolate missing fields in
custom format output used in git-log and friends.  It is most useful
to avoid <unknown> output from %b format for a commit log message
that lack any body text.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-09-26 00:40:47 -07:00

107 lines
2.1 KiB
C

/*
* Copyright 2006 Jon Loeliger
*/
#include "git-compat-util.h"
#include "interpolate.h"
void interp_set_entry(struct interp *table, int slot, const char *value)
{
char *oldval = table[slot].value;
char *newval = NULL;
if (oldval)
free(oldval);
if (value)
newval = xstrdup(value);
table[slot].value = newval;
}
void interp_clear_table(struct interp *table, int ninterps)
{
int i;
for (i = 0; i < ninterps; i++) {
interp_set_entry(table, i, NULL);
}
}
/*
* Convert a NUL-terminated string in buffer orig
* into the supplied buffer, result, whose length is reslen,
* performing substitutions on %-named sub-strings from
* the table, interps, with ninterps entries.
*
* Example interps:
* {
* { "%H", "example.org"},
* { "%port", "123"},
* { "%%", "%"},
* }
*
* Returns 0 on a successful substitution pass that fits in result,
* Returns a number of bytes needed to hold the full substituted
* string otherwise.
*/
unsigned long interpolate(char *result, unsigned long reslen,
const char *orig,
const struct interp *interps, int ninterps)
{
const char *src = orig;
char *dest = result;
unsigned long newlen = 0;
const char *name, *value;
unsigned long namelen, valuelen;
int i;
char c;
memset(result, 0, reslen);
while ((c = *src)) {
if (c == '%') {
/* Try to match an interpolation string. */
for (i = 0; i < ninterps; i++) {
name = interps[i].name;
namelen = strlen(name);
if (strncmp(src, name, namelen) == 0)
break;
}
/* Check for valid interpolation. */
if (i < ninterps) {
value = interps[i].value;
if (!value) {
src += namelen;
continue;
}
valuelen = strlen(value);
if (newlen + valuelen + 1 < reslen) {
/* Substitute. */
strncpy(dest, value, valuelen);
dest += valuelen;
}
newlen += valuelen;
src += namelen;
continue;
}
}
/* Straight copy one non-interpolation character. */
if (newlen + 1 < reslen)
*dest++ = *src;
src++;
newlen++;
}
if (newlen + 1 < reslen)
return 0;
else
return newlen + 2;
}