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![Pierre Habouzit](/assets/img/avatar_default.png)
reverse_diff was a bit-value in disguise, it's merged in the flags now. Signed-off-by: Pierre Habouzit <madcoder@debian.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
193 lines
4.7 KiB
C
193 lines
4.7 KiB
C
#include "cache.h"
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#include "diff.h"
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#include "commit.h"
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#include "patch-ids.h"
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static int commit_patch_id(struct commit *commit, struct diff_options *options,
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unsigned char *sha1)
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{
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if (commit->parents)
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diff_tree_sha1(commit->parents->item->object.sha1,
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commit->object.sha1, "", options);
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else
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diff_root_tree_sha1(commit->object.sha1, "", options);
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diffcore_std(options);
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return diff_flush_patch_id(options, sha1);
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}
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static uint32_t take2(const unsigned char *id)
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{
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return ((id[0] << 8) | id[1]);
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}
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/*
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* Conventional binary search loop looks like this:
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*
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* do {
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* int mi = (lo + hi) / 2;
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* int cmp = "entry pointed at by mi" minus "target";
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* if (!cmp)
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* return (mi is the wanted one)
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* if (cmp > 0)
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* hi = mi; "mi is larger than target"
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* else
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* lo = mi+1; "mi is smaller than target"
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* } while (lo < hi);
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*
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* The invariants are:
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*
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* - When entering the loop, lo points at a slot that is never
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* above the target (it could be at the target), hi points at a
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* slot that is guaranteed to be above the target (it can never
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* be at the target).
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*
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* - We find a point 'mi' between lo and hi (mi could be the same
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* as lo, but never can be the same as hi), and check if it hits
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* the target. There are three cases:
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*
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* - if it is a hit, we are happy.
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*
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* - if it is strictly higher than the target, we update hi with
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* it.
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*
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* - if it is strictly lower than the target, we update lo to be
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* one slot after it, because we allow lo to be at the target.
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*
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* When choosing 'mi', we do not have to take the "middle" but
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* anywhere in between lo and hi, as long as lo <= mi < hi is
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* satisfied. When we somehow know that the distance between the
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* target and lo is much shorter than the target and hi, we could
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* pick mi that is much closer to lo than the midway.
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*/
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static int patch_pos(struct patch_id **table, int nr, const unsigned char *id)
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{
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int hi = nr;
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int lo = 0;
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int mi = 0;
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if (!nr)
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return -1;
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if (nr != 1) {
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unsigned lov, hiv, miv, ofs;
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for (ofs = 0; ofs < 18; ofs += 2) {
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lov = take2(table[0]->patch_id + ofs);
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hiv = take2(table[nr-1]->patch_id + ofs);
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miv = take2(id + ofs);
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if (miv < lov)
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return -1;
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if (hiv < miv)
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return -1 - nr;
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if (lov != hiv) {
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/*
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* At this point miv could be equal
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* to hiv (but id could still be higher);
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* the invariant of (mi < hi) should be
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* kept.
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*/
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mi = (nr-1) * (miv - lov) / (hiv - lov);
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if (lo <= mi && mi < hi)
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break;
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die("oops");
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}
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}
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if (18 <= ofs)
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die("cannot happen -- lo and hi are identical");
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}
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do {
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int cmp;
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cmp = hashcmp(table[mi]->patch_id, id);
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if (!cmp)
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return mi;
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if (cmp > 0)
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hi = mi;
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else
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lo = mi + 1;
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mi = (hi + lo) / 2;
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} while (lo < hi);
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return -lo-1;
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}
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#define BUCKET_SIZE 190 /* 190 * 21 = 3990, with slop close enough to 4K */
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struct patch_id_bucket {
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struct patch_id_bucket *next;
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int nr;
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struct patch_id bucket[BUCKET_SIZE];
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};
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int init_patch_ids(struct patch_ids *ids)
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{
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memset(ids, 0, sizeof(*ids));
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diff_setup(&ids->diffopts);
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DIFF_OPT_SET(&ids->diffopts, RECURSIVE);
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if (diff_setup_done(&ids->diffopts) < 0)
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return error("diff_setup_done failed");
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return 0;
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}
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int free_patch_ids(struct patch_ids *ids)
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{
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struct patch_id_bucket *next, *patches;
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free(ids->table);
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for (patches = ids->patches; patches; patches = next) {
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next = patches->next;
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free(patches);
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}
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return 0;
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}
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static struct patch_id *add_commit(struct commit *commit,
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struct patch_ids *ids,
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int no_add)
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{
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struct patch_id_bucket *bucket;
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struct patch_id *ent;
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unsigned char sha1[20];
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int pos;
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if (commit_patch_id(commit, &ids->diffopts, sha1))
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return NULL;
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pos = patch_pos(ids->table, ids->nr, sha1);
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if (0 <= pos)
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return ids->table[pos];
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if (no_add)
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return NULL;
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pos = -1 - pos;
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bucket = ids->patches;
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if (!bucket || (BUCKET_SIZE <= bucket->nr)) {
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bucket = xcalloc(1, sizeof(*bucket));
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bucket->next = ids->patches;
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ids->patches = bucket;
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}
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ent = &bucket->bucket[bucket->nr++];
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hashcpy(ent->patch_id, sha1);
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if (ids->alloc <= ids->nr) {
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ids->alloc = alloc_nr(ids->nr);
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ids->table = xrealloc(ids->table, sizeof(ent) * ids->alloc);
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}
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if (pos < ids->nr)
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memmove(ids->table + pos + 1, ids->table + pos,
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sizeof(ent) * (ids->nr - pos));
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ids->nr++;
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ids->table[pos] = ent;
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return ids->table[pos];
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}
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struct patch_id *has_commit_patch_id(struct commit *commit,
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struct patch_ids *ids)
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{
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return add_commit(commit, ids, 1);
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}
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struct patch_id *add_commit_patch_id(struct commit *commit,
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struct patch_ids *ids)
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{
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return add_commit(commit, ids, 0);
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}
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