git/versioncmp.c
SZEDER Gábor 109064a031 versioncmp: pass full tagnames to swap_prereleases()
The swap_prereleases() helper function is responsible for finding
configured prerelease suffixes in a pair of tagnames to be compared,
but this function currently gets to see only the parts of those two
tagnames starting at the first different character.  To fix some
issues related to the common part of two tagnames overlapping with
leading part of a prerelease suffix, this helper function must see
both full tagnames.

In preparation for the fix in the following patch, refactor
swap_prereleases() and its caller to pass two full tagnames and an
additional offset indicating the position of the first different
character.

While updating the comment describing that function, remove the
sentence about not dealing with both tagnames having the same suffix.
Currently it doesn't add much value (we know that there is a different
character, so it's obvious that it can't possibly be the same suffix
in both), and at the end of this patch series it won't even be true
anymore.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-12-08 11:11:57 -08:00

141 lines
3.4 KiB
C

#include "cache.h"
#include "string-list.h"
/*
* versioncmp(): copied from string/strverscmp.c in glibc commit
* ee9247c38a8def24a59eb5cfb7196a98bef8cfdc, reformatted to Git coding
* style. The implementation is under LGPL-2.1 and Git relicenses it
* to GPLv2.
*/
/*
* states: S_N: normal, S_I: comparing integral part, S_F: comparing
* fractionnal parts, S_Z: idem but with leading Zeroes only
*/
#define S_N 0x0
#define S_I 0x3
#define S_F 0x6
#define S_Z 0x9
/* result_type: CMP: return diff; LEN: compare using len_diff/diff */
#define CMP 2
#define LEN 3
static const struct string_list *prereleases;
static int initialized;
/*
* off is the offset of the first different character in the two strings
* s1 and s2. If either s1 or s2 contains a prerelease suffix starting
* at that offset, it will be forced to be on top.
*
* If both s1 and s2 contain a (different) suffix at that position,
* their order is determined by the order of those two suffixes in the
* configuration.
*
* Return non-zero if *diff contains the return value for versioncmp()
*/
static int swap_prereleases(const char *s1,
const char *s2,
int off,
int *diff)
{
int i, i1 = -1, i2 = -1;
for (i = 0; i < prereleases->nr; i++) {
const char *suffix = prereleases->items[i].string;
if (i1 == -1 && starts_with(s1 + off, suffix))
i1 = i;
if (i2 == -1 && starts_with(s2 + off, suffix))
i2 = i;
}
if (i1 == -1 && i2 == -1)
return 0;
if (i1 >= 0 && i2 >= 0)
*diff = i1 - i2;
else if (i1 >= 0)
*diff = -1;
else /* if (i2 >= 0) */
*diff = 1;
return 1;
}
/*
* Compare S1 and S2 as strings holding indices/version numbers,
* returning less than, equal to or greater than zero if S1 is less
* than, equal to or greater than S2 (for more info, see the texinfo
* doc).
*/
int versioncmp(const char *s1, const char *s2)
{
const unsigned char *p1 = (const unsigned char *) s1;
const unsigned char *p2 = (const unsigned char *) s2;
unsigned char c1, c2;
int state, diff;
/*
* Symbol(s) 0 [1-9] others
* Transition (10) 0 (01) d (00) x
*/
static const uint8_t next_state[] = {
/* state x d 0 */
/* S_N */ S_N, S_I, S_Z,
/* S_I */ S_N, S_I, S_I,
/* S_F */ S_N, S_F, S_F,
/* S_Z */ S_N, S_F, S_Z
};
static const int8_t result_type[] = {
/* state x/x x/d x/0 d/x d/d d/0 0/x 0/d 0/0 */
/* S_N */ CMP, CMP, CMP, CMP, LEN, CMP, CMP, CMP, CMP,
/* S_I */ CMP, -1, -1, +1, LEN, LEN, +1, LEN, LEN,
/* S_F */ CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP,
/* S_Z */ CMP, +1, +1, -1, CMP, CMP, -1, CMP, CMP
};
if (p1 == p2)
return 0;
c1 = *p1++;
c2 = *p2++;
/* Hint: '0' is a digit too. */
state = S_N + ((c1 == '0') + (isdigit (c1) != 0));
while ((diff = c1 - c2) == 0) {
if (c1 == '\0')
return diff;
state = next_state[state];
c1 = *p1++;
c2 = *p2++;
state += (c1 == '0') + (isdigit (c1) != 0);
}
if (!initialized) {
initialized = 1;
prereleases = git_config_get_value_multi("versionsort.prereleasesuffix");
}
if (prereleases && swap_prereleases(s1, s2, (const char *) p1 - s1 - 1,
&diff))
return diff;
state = result_type[state * 3 + (((c2 == '0') + (isdigit (c2) != 0)))];
switch (state) {
case CMP:
return diff;
case LEN:
while (isdigit (*p1++))
if (!isdigit (*p2++))
return 1;
return isdigit (*p2) ? -1 : diff;
default:
return state;
}
}