#include "cache.h"
#include "diff.h"
#include "commit.h"
+#include "sha1-lookup.h"
#include "patch-ids.h"
-static int commit_patch_id(struct commit *commit, struct diff_options *options,
- unsigned char *sha1)
+static int patch_id_defined(struct commit *commit)
{
- 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);
+ /* must be 0 or 1 parents */
+ return !commit->parents || !commit->parents->next;
}
-static uint32_t take2(const unsigned char *id)
+int commit_patch_id(struct commit *commit, struct diff_options *options,
+ unsigned char *sha1, int diff_header_only)
{
- return ((id[0] << 8) | id[1]);
+ if (!patch_id_defined(commit))
+ return -1;
+
+ if (commit->parents)
+ diff_tree_sha1(commit->parents->item->object.oid.hash,
+ commit->object.oid.hash, "", options);
+ else
+ diff_root_tree_sha1(commit->object.oid.hash, "", options);
+ diffcore_std(options);
+ return diff_flush_patch_id(options, sha1, diff_header_only);
}
/*
- * 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.
+ * When we cannot load the full patch-id for both commits for whatever
+ * reason, the function returns -1 (i.e. return error(...)). Despite
+ * the "cmp" in the name of this function, the caller only cares about
+ * the return value being zero (a and b are equivalent) or non-zero (a
+ * and b are different), and returning non-zero would keep both in the
+ * result, even if they actually were equivalent, in order to err on
+ * the side of safety. The actual value being negative does not have
+ * any significance; only that it is non-zero matters.
*/
-static int patch_pos(struct patch_id **table, int nr, const unsigned char *id)
+static int patch_id_cmp(struct patch_id *a,
+ struct patch_id *b,
+ struct diff_options *opt)
{
- 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;
+ if (is_null_sha1(a->patch_id) &&
+ commit_patch_id(a->commit, opt, a->patch_id, 0))
+ return error("Could not get patch ID for %s",
+ oid_to_hex(&a->commit->object.oid));
+ if (is_null_sha1(b->patch_id) &&
+ commit_patch_id(b->commit, opt, b->patch_id, 0))
+ return error("Could not get patch ID for %s",
+ oid_to_hex(&b->commit->object.oid));
+ return hashcmp(a->patch_id, b->patch_id);
}
-#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);
+ ids->diffopts.detect_rename = 0;
DIFF_OPT_SET(&ids->diffopts, RECURSIVE);
- if (diff_setup_done(&ids->diffopts) < 0)
- return error("diff_setup_done failed");
+ diff_setup_done(&ids->diffopts);
+ hashmap_init(&ids->patches, (hashmap_cmp_fn)patch_id_cmp, 256);
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);
- }
+ hashmap_free(&ids->patches, 1);
return 0;
}
-static struct patch_id *add_commit(struct commit *commit,
- struct patch_ids *ids,
- int no_add)
+static int init_patch_id_entry(struct patch_id *patch,
+ struct commit *commit,
+ struct patch_ids *ids)
{
- struct patch_id_bucket *bucket;
- struct patch_id *ent;
- unsigned char sha1[20];
- int pos;
+ unsigned char header_only_patch_id[GIT_SHA1_RAWSZ];
- 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);
+ patch->commit = commit;
+ if (commit_patch_id(commit, &ids->diffopts, header_only_patch_id, 1))
+ return -1;
- 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];
+ hashmap_entry_init(patch, sha1hash(header_only_patch_id));
+ return 0;
}
struct patch_id *has_commit_patch_id(struct commit *commit,
struct patch_ids *ids)
{
- return add_commit(commit, ids, 1);
+ struct patch_id patch;
+
+ if (!patch_id_defined(commit))
+ return NULL;
+
+ memset(&patch, 0, sizeof(patch));
+ if (init_patch_id_entry(&patch, commit, ids))
+ return NULL;
+
+ return hashmap_get(&ids->patches, &patch, &ids->diffopts);
}
struct patch_id *add_commit_patch_id(struct commit *commit,
struct patch_ids *ids)
{
- return add_commit(commit, ids, 0);
+ struct patch_id *key = xcalloc(1, sizeof(*key));
+
+ if (!patch_id_defined(commit))
+ return NULL;
+
+ if (init_patch_id_entry(key, commit, ids)) {
+ free(key);
+ return NULL;
+ }
+
+ hashmap_add(&ids->patches, key);
+ return key;
}