Revision 421b488a58fea89ceb55d5b358738e9251d44f5e authored by Jeff King on 23 October 2008, 04:31:03 UTC, committed by Junio C Hamano on 02 November 2008, 06:46:40 UTC
In the main loop of find_deltas, we do: struct object_entry *entry = *list++; ... if (!*list_size) ... break Because we look at and increment *list _before_ the check of list_size, in the very last iteration of the loop we will look at uninitialized data, and increment the pointer beyond one past the end of the allocated space. Since we don't actually do anything with the data until after the check, this is not a problem in practice. But since it technically violates the C standard, and because it provokes a spurious valgrind warning, let's just move the initialization of entry to a safe place. This fixes valgrind errors in t5300, t5301, t5302, t303, and t9400. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 parent 13494ed
patch-ids.c
#include "cache.h"
#include "diff.h"
#include "commit.h"
#include "patch-ids.h"
static int commit_patch_id(struct commit *commit, struct diff_options *options,
unsigned char *sha1)
{
if (commit->parents)
diff_tree_sha1(commit->parents->item->object.sha1,
commit->object.sha1, "", options);
else
diff_root_tree_sha1(commit->object.sha1, "", options);
diffcore_std(options);
return diff_flush_patch_id(options, sha1);
}
static uint32_t take2(const unsigned char *id)
{
return ((id[0] << 8) | id[1]);
}
/*
* Conventional binary search loop looks like this:
*
* do {
* int mi = (lo + hi) / 2;
* int cmp = "entry pointed at by mi" minus "target";
* if (!cmp)
* return (mi is the wanted one)
* if (cmp > 0)
* hi = mi; "mi is larger than target"
* else
* lo = mi+1; "mi is smaller than target"
* } while (lo < hi);
*
* The invariants are:
*
* - When entering the loop, lo points at a slot that is never
* above the target (it could be at the target), hi points at a
* slot that is guaranteed to be above the target (it can never
* be at the target).
*
* - We find a point 'mi' between lo and hi (mi could be the same
* as lo, but never can be the same as hi), and check if it hits
* the target. There are three cases:
*
* - if it is a hit, we are happy.
*
* - if it is strictly higher than the target, we update hi with
* it.
*
* - if it is strictly lower than the target, we update lo to be
* one slot after it, because we allow lo to be at the target.
*
* When choosing 'mi', we do not have to take the "middle" but
* anywhere in between lo and hi, as long as lo <= mi < hi is
* satisfied. When we somehow know that the distance between the
* target and lo is much shorter than the target and hi, we could
* pick mi that is much closer to lo than the midway.
*/
static int patch_pos(struct patch_id **table, int nr, const unsigned char *id)
{
int hi = nr;
int lo = 0;
int mi = 0;
if (!nr)
return -1;
if (nr != 1) {
unsigned lov, hiv, miv, ofs;
for (ofs = 0; ofs < 18; ofs += 2) {
lov = take2(table[0]->patch_id + ofs);
hiv = take2(table[nr-1]->patch_id + ofs);
miv = take2(id + ofs);
if (miv < lov)
return -1;
if (hiv < miv)
return -1 - nr;
if (lov != hiv) {
/*
* At this point miv could be equal
* to hiv (but id could still be higher);
* the invariant of (mi < hi) should be
* kept.
*/
mi = (nr-1) * (miv - lov) / (hiv - lov);
if (lo <= mi && mi < hi)
break;
die("oops");
}
}
if (18 <= ofs)
die("cannot happen -- lo and hi are identical");
}
do {
int cmp;
cmp = hashcmp(table[mi]->patch_id, id);
if (!cmp)
return mi;
if (cmp > 0)
hi = mi;
else
lo = mi + 1;
mi = (hi + lo) / 2;
} while (lo < hi);
return -lo-1;
}
#define BUCKET_SIZE 190 /* 190 * 21 = 3990, with slop close enough to 4K */
struct patch_id_bucket {
struct patch_id_bucket *next;
int nr;
struct patch_id bucket[BUCKET_SIZE];
};
int init_patch_ids(struct patch_ids *ids)
{
memset(ids, 0, sizeof(*ids));
diff_setup(&ids->diffopts);
DIFF_OPT_SET(&ids->diffopts, RECURSIVE);
if (diff_setup_done(&ids->diffopts) < 0)
return error("diff_setup_done failed");
return 0;
}
int free_patch_ids(struct patch_ids *ids)
{
struct patch_id_bucket *next, *patches;
free(ids->table);
for (patches = ids->patches; patches; patches = next) {
next = patches->next;
free(patches);
}
return 0;
}
static struct patch_id *add_commit(struct commit *commit,
struct patch_ids *ids,
int no_add)
{
struct patch_id_bucket *bucket;
struct patch_id *ent;
unsigned char sha1[20];
int pos;
if (commit_patch_id(commit, &ids->diffopts, sha1))
return NULL;
pos = patch_pos(ids->table, ids->nr, sha1);
if (0 <= pos)
return ids->table[pos];
if (no_add)
return NULL;
pos = -1 - pos;
bucket = ids->patches;
if (!bucket || (BUCKET_SIZE <= bucket->nr)) {
bucket = xcalloc(1, sizeof(*bucket));
bucket->next = ids->patches;
ids->patches = bucket;
}
ent = &bucket->bucket[bucket->nr++];
hashcpy(ent->patch_id, sha1);
if (ids->alloc <= ids->nr) {
ids->alloc = alloc_nr(ids->nr);
ids->table = xrealloc(ids->table, sizeof(ent) * ids->alloc);
}
if (pos < ids->nr)
memmove(ids->table + pos + 1, ids->table + pos,
sizeof(ent) * (ids->nr - pos));
ids->nr++;
ids->table[pos] = ent;
return ids->table[pos];
}
struct patch_id *has_commit_patch_id(struct commit *commit,
struct patch_ids *ids)
{
return add_commit(commit, ids, 1);
}
struct patch_id *add_commit_patch_id(struct commit *commit,
struct patch_ids *ids)
{
return add_commit(commit, ids, 0);
}
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