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9518864816
This patch implements a new "filter_skip" function in C in "bisect.c" that will later replace the existing implementation in shell in "git-bisect.sh". An array is used to store the skipped commits. But the array is not yet fed anything. Signed-off-by: Christian Couder <chriscool@tuxfamily.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
452 lines
9.8 KiB
C
452 lines
9.8 KiB
C
#include "cache.h"
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#include "commit.h"
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#include "diff.h"
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#include "revision.h"
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#include "bisect.h"
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static unsigned char (*skipped_sha1)[20];
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static int skipped_sha1_nr;
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/* bits #0-15 in revision.h */
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#define COUNTED (1u<<16)
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/*
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* This is a truly stupid algorithm, but it's only
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* used for bisection, and we just don't care enough.
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*
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* We care just barely enough to avoid recursing for
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* non-merge entries.
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*/
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static int count_distance(struct commit_list *entry)
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{
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int nr = 0;
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while (entry) {
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struct commit *commit = entry->item;
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struct commit_list *p;
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if (commit->object.flags & (UNINTERESTING | COUNTED))
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break;
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if (!(commit->object.flags & TREESAME))
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nr++;
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commit->object.flags |= COUNTED;
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p = commit->parents;
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entry = p;
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if (p) {
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p = p->next;
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while (p) {
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nr += count_distance(p);
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p = p->next;
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}
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}
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}
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return nr;
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}
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static void clear_distance(struct commit_list *list)
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{
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while (list) {
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struct commit *commit = list->item;
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commit->object.flags &= ~COUNTED;
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list = list->next;
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}
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}
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#define DEBUG_BISECT 0
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static inline int weight(struct commit_list *elem)
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{
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return *((int*)(elem->item->util));
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}
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static inline void weight_set(struct commit_list *elem, int weight)
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{
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*((int*)(elem->item->util)) = weight;
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}
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static int count_interesting_parents(struct commit *commit)
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{
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struct commit_list *p;
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int count;
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for (count = 0, p = commit->parents; p; p = p->next) {
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if (p->item->object.flags & UNINTERESTING)
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continue;
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count++;
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}
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return count;
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}
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static inline int halfway(struct commit_list *p, int nr)
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{
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/*
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* Don't short-cut something we are not going to return!
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*/
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if (p->item->object.flags & TREESAME)
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return 0;
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if (DEBUG_BISECT)
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return 0;
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/*
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* 2 and 3 are halfway of 5.
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* 3 is halfway of 6 but 2 and 4 are not.
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*/
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switch (2 * weight(p) - nr) {
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case -1: case 0: case 1:
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return 1;
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default:
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return 0;
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}
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}
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#if !DEBUG_BISECT
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#define show_list(a,b,c,d) do { ; } while (0)
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#else
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static void show_list(const char *debug, int counted, int nr,
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struct commit_list *list)
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{
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struct commit_list *p;
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fprintf(stderr, "%s (%d/%d)\n", debug, counted, nr);
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for (p = list; p; p = p->next) {
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struct commit_list *pp;
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struct commit *commit = p->item;
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unsigned flags = commit->object.flags;
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enum object_type type;
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unsigned long size;
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char *buf = read_sha1_file(commit->object.sha1, &type, &size);
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char *ep, *sp;
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fprintf(stderr, "%c%c%c ",
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(flags & TREESAME) ? ' ' : 'T',
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(flags & UNINTERESTING) ? 'U' : ' ',
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(flags & COUNTED) ? 'C' : ' ');
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if (commit->util)
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fprintf(stderr, "%3d", weight(p));
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else
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fprintf(stderr, "---");
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fprintf(stderr, " %.*s", 8, sha1_to_hex(commit->object.sha1));
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for (pp = commit->parents; pp; pp = pp->next)
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fprintf(stderr, " %.*s", 8,
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sha1_to_hex(pp->item->object.sha1));
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sp = strstr(buf, "\n\n");
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if (sp) {
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sp += 2;
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for (ep = sp; *ep && *ep != '\n'; ep++)
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;
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fprintf(stderr, " %.*s", (int)(ep - sp), sp);
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}
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fprintf(stderr, "\n");
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}
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}
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#endif /* DEBUG_BISECT */
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static struct commit_list *best_bisection(struct commit_list *list, int nr)
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{
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struct commit_list *p, *best;
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int best_distance = -1;
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best = list;
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for (p = list; p; p = p->next) {
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int distance;
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unsigned flags = p->item->object.flags;
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if (flags & TREESAME)
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continue;
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distance = weight(p);
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if (nr - distance < distance)
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distance = nr - distance;
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if (distance > best_distance) {
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best = p;
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best_distance = distance;
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}
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}
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return best;
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}
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struct commit_dist {
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struct commit *commit;
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int distance;
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};
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static int compare_commit_dist(const void *a_, const void *b_)
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{
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struct commit_dist *a, *b;
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a = (struct commit_dist *)a_;
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b = (struct commit_dist *)b_;
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if (a->distance != b->distance)
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return b->distance - a->distance; /* desc sort */
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return hashcmp(a->commit->object.sha1, b->commit->object.sha1);
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}
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static struct commit_list *best_bisection_sorted(struct commit_list *list, int nr)
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{
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struct commit_list *p;
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struct commit_dist *array = xcalloc(nr, sizeof(*array));
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int cnt, i;
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for (p = list, cnt = 0; p; p = p->next) {
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int distance;
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unsigned flags = p->item->object.flags;
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if (flags & TREESAME)
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continue;
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distance = weight(p);
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if (nr - distance < distance)
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distance = nr - distance;
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array[cnt].commit = p->item;
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array[cnt].distance = distance;
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cnt++;
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}
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qsort(array, cnt, sizeof(*array), compare_commit_dist);
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for (p = list, i = 0; i < cnt; i++) {
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struct name_decoration *r = xmalloc(sizeof(*r) + 100);
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struct object *obj = &(array[i].commit->object);
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sprintf(r->name, "dist=%d", array[i].distance);
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r->next = add_decoration(&name_decoration, obj, r);
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p->item = array[i].commit;
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p = p->next;
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}
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if (p)
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p->next = NULL;
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free(array);
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return list;
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}
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/*
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* zero or positive weight is the number of interesting commits it can
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* reach, including itself. Especially, weight = 0 means it does not
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* reach any tree-changing commits (e.g. just above uninteresting one
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* but traversal is with pathspec).
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*
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* weight = -1 means it has one parent and its distance is yet to
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* be computed.
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*
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* weight = -2 means it has more than one parent and its distance is
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* unknown. After running count_distance() first, they will get zero
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* or positive distance.
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*/
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static struct commit_list *do_find_bisection(struct commit_list *list,
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int nr, int *weights,
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int find_all)
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{
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int n, counted;
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struct commit_list *p;
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counted = 0;
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for (n = 0, p = list; p; p = p->next) {
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struct commit *commit = p->item;
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unsigned flags = commit->object.flags;
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p->item->util = &weights[n++];
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switch (count_interesting_parents(commit)) {
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case 0:
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if (!(flags & TREESAME)) {
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weight_set(p, 1);
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counted++;
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show_list("bisection 2 count one",
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counted, nr, list);
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}
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/*
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* otherwise, it is known not to reach any
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* tree-changing commit and gets weight 0.
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*/
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break;
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case 1:
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weight_set(p, -1);
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break;
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default:
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weight_set(p, -2);
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break;
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}
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}
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show_list("bisection 2 initialize", counted, nr, list);
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/*
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* If you have only one parent in the resulting set
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* then you can reach one commit more than that parent
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* can reach. So we do not have to run the expensive
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* count_distance() for single strand of pearls.
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*
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* However, if you have more than one parents, you cannot
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* just add their distance and one for yourself, since
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* they usually reach the same ancestor and you would
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* end up counting them twice that way.
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*
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* So we will first count distance of merges the usual
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* way, and then fill the blanks using cheaper algorithm.
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*/
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for (p = list; p; p = p->next) {
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if (p->item->object.flags & UNINTERESTING)
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continue;
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if (weight(p) != -2)
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continue;
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weight_set(p, count_distance(p));
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clear_distance(list);
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/* Does it happen to be at exactly half-way? */
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if (!find_all && halfway(p, nr))
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return p;
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counted++;
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}
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show_list("bisection 2 count_distance", counted, nr, list);
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while (counted < nr) {
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for (p = list; p; p = p->next) {
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struct commit_list *q;
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unsigned flags = p->item->object.flags;
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if (0 <= weight(p))
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continue;
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for (q = p->item->parents; q; q = q->next) {
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if (q->item->object.flags & UNINTERESTING)
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continue;
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if (0 <= weight(q))
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break;
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}
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if (!q)
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continue;
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/*
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* weight for p is unknown but q is known.
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* add one for p itself if p is to be counted,
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* otherwise inherit it from q directly.
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*/
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if (!(flags & TREESAME)) {
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weight_set(p, weight(q)+1);
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counted++;
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show_list("bisection 2 count one",
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counted, nr, list);
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}
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else
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weight_set(p, weight(q));
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/* Does it happen to be at exactly half-way? */
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if (!find_all && halfway(p, nr))
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return p;
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}
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}
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show_list("bisection 2 counted all", counted, nr, list);
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if (!find_all)
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return best_bisection(list, nr);
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else
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return best_bisection_sorted(list, nr);
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}
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struct commit_list *find_bisection(struct commit_list *list,
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int *reaches, int *all,
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int find_all)
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{
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int nr, on_list;
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struct commit_list *p, *best, *next, *last;
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int *weights;
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show_list("bisection 2 entry", 0, 0, list);
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/*
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* Count the number of total and tree-changing items on the
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* list, while reversing the list.
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*/
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for (nr = on_list = 0, last = NULL, p = list;
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p;
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p = next) {
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unsigned flags = p->item->object.flags;
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next = p->next;
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if (flags & UNINTERESTING)
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continue;
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p->next = last;
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last = p;
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if (!(flags & TREESAME))
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nr++;
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on_list++;
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}
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list = last;
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show_list("bisection 2 sorted", 0, nr, list);
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*all = nr;
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weights = xcalloc(on_list, sizeof(*weights));
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/* Do the real work of finding bisection commit. */
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best = do_find_bisection(list, nr, weights, find_all);
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if (best) {
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if (!find_all)
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best->next = NULL;
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*reaches = weight(best);
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}
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free(weights);
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return best;
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}
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static int skipcmp(const void *a, const void *b)
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{
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return hashcmp(a, b);
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}
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static void prepare_skipped(void)
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{
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qsort(skipped_sha1, skipped_sha1_nr, sizeof(*skipped_sha1), skipcmp);
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}
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static int lookup_skipped(unsigned char *sha1)
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{
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int lo, hi;
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lo = 0;
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hi = skipped_sha1_nr;
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while (lo < hi) {
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int mi = (lo + hi) / 2;
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int cmp = hashcmp(sha1, skipped_sha1[mi]);
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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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}
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return -lo - 1;
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}
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struct commit_list *filter_skipped(struct commit_list *list,
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struct commit_list **tried,
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int show_all)
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{
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struct commit_list *filtered = NULL, **f = &filtered;
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*tried = NULL;
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if (!skipped_sha1_nr)
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return list;
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prepare_skipped();
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while (list) {
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struct commit_list *next = list->next;
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list->next = NULL;
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if (0 <= lookup_skipped(list->item->object.sha1)) {
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/* Move current to tried list */
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*tried = list;
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tried = &list->next;
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} else {
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if (!show_all)
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return list;
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/* Move current to filtered list */
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*f = list;
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f = &list->next;
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}
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list = next;
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}
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return filtered;
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}
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