#include "cache.h"
-#include "refs.h"
-#include "tag.h"
#include "commit.h"
-#include "tree.h"
-#include "blob.h"
-#include "tree-walk.h"
#include "diff.h"
#include "revision.h"
#include "list-objects.h"
#include "builtin.h"
#include "log-tree.h"
#include "graph.h"
-
-/* bits #0-15 in revision.h */
-
-#define COUNTED (1u<<16)
+#include "bisect.h"
static const char rev_list_usage[] =
"git rev-list [OPTION] <commit-id>... [ -- paths... ]\n"
static struct rev_info revs;
-static int bisect_list;
static int show_timestamp;
static int hdr_termination;
static const char *header_prefix;
printf("-%s\n", sha1_to_hex(commit->object.sha1));
}
-/*
- * This is a truly stupid algorithm, but it's only
- * used for bisection, and we just don't care enough.
- *
- * We care just barely enough to avoid recursing for
- * non-merge entries.
- */
-static int count_distance(struct commit_list *entry)
-{
- int nr = 0;
-
- while (entry) {
- struct commit *commit = entry->item;
- struct commit_list *p;
-
- if (commit->object.flags & (UNINTERESTING | COUNTED))
- break;
- if (!(commit->object.flags & TREESAME))
- nr++;
- commit->object.flags |= COUNTED;
- p = commit->parents;
- entry = p;
- if (p) {
- p = p->next;
- while (p) {
- nr += count_distance(p);
- p = p->next;
- }
- }
- }
-
- return nr;
-}
-
-static void clear_distance(struct commit_list *list)
+static inline int log2i(int n)
{
- while (list) {
- struct commit *commit = list->item;
- commit->object.flags &= ~COUNTED;
- list = list->next;
- }
-}
-
-#define DEBUG_BISECT 0
+ int log2 = 0;
-static inline int weight(struct commit_list *elem)
-{
- return *((int*)(elem->item->util));
-}
+ for (; n > 1; n >>= 1)
+ log2++;
-static inline void weight_set(struct commit_list *elem, int weight)
-{
- *((int*)(elem->item->util)) = weight;
+ return log2;
}
-static int count_interesting_parents(struct commit *commit)
+static inline int exp2i(int n)
{
- struct commit_list *p;
- int count;
-
- for (count = 0, p = commit->parents; p; p = p->next) {
- if (p->item->object.flags & UNINTERESTING)
- continue;
- count++;
- }
- return count;
-}
-
-static inline int halfway(struct commit_list *p, int nr)
-{
- /*
- * Don't short-cut something we are not going to return!
- */
- if (p->item->object.flags & TREESAME)
- return 0;
- if (DEBUG_BISECT)
- return 0;
- /*
- * 2 and 3 are halfway of 5.
- * 3 is halfway of 6 but 2 and 4 are not.
- */
- switch (2 * weight(p) - nr) {
- case -1: case 0: case 1:
- return 1;
- default:
- return 0;
- }
-}
-
-#if !DEBUG_BISECT
-#define show_list(a,b,c,d) do { ; } while (0)
-#else
-static void show_list(const char *debug, int counted, int nr,
- struct commit_list *list)
-{
- struct commit_list *p;
-
- fprintf(stderr, "%s (%d/%d)\n", debug, counted, nr);
-
- for (p = list; p; p = p->next) {
- struct commit_list *pp;
- struct commit *commit = p->item;
- unsigned flags = commit->object.flags;
- enum object_type type;
- unsigned long size;
- char *buf = read_sha1_file(commit->object.sha1, &type, &size);
- char *ep, *sp;
-
- fprintf(stderr, "%c%c%c ",
- (flags & TREESAME) ? ' ' : 'T',
- (flags & UNINTERESTING) ? 'U' : ' ',
- (flags & COUNTED) ? 'C' : ' ');
- if (commit->util)
- fprintf(stderr, "%3d", weight(p));
- else
- fprintf(stderr, "---");
- fprintf(stderr, " %.*s", 8, sha1_to_hex(commit->object.sha1));
- for (pp = commit->parents; pp; pp = pp->next)
- fprintf(stderr, " %.*s", 8,
- sha1_to_hex(pp->item->object.sha1));
-
- sp = strstr(buf, "\n\n");
- if (sp) {
- sp += 2;
- for (ep = sp; *ep && *ep != '\n'; ep++)
- ;
- fprintf(stderr, " %.*s", (int)(ep - sp), sp);
- }
- fprintf(stderr, "\n");
- }
-}
-#endif /* DEBUG_BISECT */
-
-static struct commit_list *best_bisection(struct commit_list *list, int nr)
-{
- struct commit_list *p, *best;
- int best_distance = -1;
-
- best = list;
- for (p = list; p; p = p->next) {
- int distance;
- unsigned flags = p->item->object.flags;
-
- if (flags & TREESAME)
- continue;
- distance = weight(p);
- if (nr - distance < distance)
- distance = nr - distance;
- if (distance > best_distance) {
- best = p;
- best_distance = distance;
- }
- }
-
- return best;
-}
-
-struct commit_dist {
- struct commit *commit;
- int distance;
-};
-
-static int compare_commit_dist(const void *a_, const void *b_)
-{
- struct commit_dist *a, *b;
-
- a = (struct commit_dist *)a_;
- b = (struct commit_dist *)b_;
- if (a->distance != b->distance)
- return b->distance - a->distance; /* desc sort */
- return hashcmp(a->commit->object.sha1, b->commit->object.sha1);
-}
-
-static struct commit_list *best_bisection_sorted(struct commit_list *list, int nr)
-{
- struct commit_list *p;
- struct commit_dist *array = xcalloc(nr, sizeof(*array));
- int cnt, i;
-
- for (p = list, cnt = 0; p; p = p->next) {
- int distance;
- unsigned flags = p->item->object.flags;
-
- if (flags & TREESAME)
- continue;
- distance = weight(p);
- if (nr - distance < distance)
- distance = nr - distance;
- array[cnt].commit = p->item;
- array[cnt].distance = distance;
- cnt++;
- }
- qsort(array, cnt, sizeof(*array), compare_commit_dist);
- for (p = list, i = 0; i < cnt; i++) {
- struct name_decoration *r = xmalloc(sizeof(*r) + 100);
- struct object *obj = &(array[i].commit->object);
-
- sprintf(r->name, "dist=%d", array[i].distance);
- r->next = add_decoration(&name_decoration, obj, r);
- p->item = array[i].commit;
- p = p->next;
- }
- if (p)
- p->next = NULL;
- free(array);
- return list;
+ return 1 << n;
}
/*
- * zero or positive weight is the number of interesting commits it can
- * reach, including itself. Especially, weight = 0 means it does not
- * reach any tree-changing commits (e.g. just above uninteresting one
- * but traversal is with pathspec).
+ * Estimate the number of bisect steps left (after the current step)
+ *
+ * For any x between 0 included and 2^n excluded, the probability for
+ * n - 1 steps left looks like:
*
- * weight = -1 means it has one parent and its distance is yet to
- * be computed.
+ * P(2^n + x) == (2^n - x) / (2^n + x)
*
- * weight = -2 means it has more than one parent and its distance is
- * unknown. After running count_distance() first, they will get zero
- * or positive distance.
+ * and P(2^n + x) < 0.5 means 2^n < 3x
*/
-static struct commit_list *do_find_bisection(struct commit_list *list,
- int nr, int *weights,
- int find_all)
+static int estimate_bisect_steps(int all)
{
- int n, counted;
- struct commit_list *p;
-
- counted = 0;
-
- for (n = 0, p = list; p; p = p->next) {
- struct commit *commit = p->item;
- unsigned flags = commit->object.flags;
-
- p->item->util = &weights[n++];
- switch (count_interesting_parents(commit)) {
- case 0:
- if (!(flags & TREESAME)) {
- weight_set(p, 1);
- counted++;
- show_list("bisection 2 count one",
- counted, nr, list);
- }
- /*
- * otherwise, it is known not to reach any
- * tree-changing commit and gets weight 0.
- */
- break;
- case 1:
- weight_set(p, -1);
- break;
- default:
- weight_set(p, -2);
- break;
- }
- }
-
- show_list("bisection 2 initialize", counted, nr, list);
-
- /*
- * If you have only one parent in the resulting set
- * then you can reach one commit more than that parent
- * can reach. So we do not have to run the expensive
- * count_distance() for single strand of pearls.
- *
- * However, if you have more than one parents, you cannot
- * just add their distance and one for yourself, since
- * they usually reach the same ancestor and you would
- * end up counting them twice that way.
- *
- * So we will first count distance of merges the usual
- * way, and then fill the blanks using cheaper algorithm.
- */
- for (p = list; p; p = p->next) {
- if (p->item->object.flags & UNINTERESTING)
- continue;
- if (weight(p) != -2)
- continue;
- weight_set(p, count_distance(p));
- clear_distance(list);
-
- /* Does it happen to be at exactly half-way? */
- if (!find_all && halfway(p, nr))
- return p;
- counted++;
- }
-
- show_list("bisection 2 count_distance", counted, nr, list);
-
- while (counted < nr) {
- for (p = list; p; p = p->next) {
- struct commit_list *q;
- unsigned flags = p->item->object.flags;
-
- if (0 <= weight(p))
- continue;
- for (q = p->item->parents; q; q = q->next) {
- if (q->item->object.flags & UNINTERESTING)
- continue;
- if (0 <= weight(q))
- break;
- }
- if (!q)
- continue;
-
- /*
- * weight for p is unknown but q is known.
- * add one for p itself if p is to be counted,
- * otherwise inherit it from q directly.
- */
- if (!(flags & TREESAME)) {
- weight_set(p, weight(q)+1);
- counted++;
- show_list("bisection 2 count one",
- counted, nr, list);
- }
- else
- weight_set(p, weight(q));
+ int n, x, e;
- /* Does it happen to be at exactly half-way? */
- if (!find_all && halfway(p, nr))
- return p;
- }
- }
+ if (all < 3)
+ return 0;
- show_list("bisection 2 counted all", counted, nr, list);
+ n = log2i(all);
+ e = exp2i(n);
+ x = all - e;
- if (!find_all)
- return best_bisection(list, nr);
- else
- return best_bisection_sorted(list, nr);
+ return (e < 3 * x) ? n : n - 1;
}
-static struct commit_list *find_bisection(struct commit_list *list,
- int *reaches, int *all,
- int find_all)
+int show_bisect_vars(struct rev_info *revs, int reaches, int all, int show_all)
{
- int nr, on_list;
- struct commit_list *p, *best, *next, *last;
- int *weights;
+ int cnt;
+ char hex[41];
- show_list("bisection 2 entry", 0, 0, list);
+ if (!revs->commits)
+ return 1;
/*
- * Count the number of total and tree-changing items on the
- * list, while reversing the list.
+ * revs->commits can reach "reaches" commits among
+ * "all" commits. If it is good, then there are
+ * (all-reaches) commits left to be bisected.
+ * On the other hand, if it is bad, then the set
+ * to bisect is "reaches".
+ * A bisect set of size N has (N-1) commits further
+ * to test, as we already know one bad one.
*/
- for (nr = on_list = 0, last = NULL, p = list;
- p;
- p = next) {
- unsigned flags = p->item->object.flags;
+ cnt = all - reaches;
+ if (cnt < reaches)
+ cnt = reaches;
- next = p->next;
- if (flags & UNINTERESTING)
- continue;
- p->next = last;
- last = p;
- if (!(flags & TREESAME))
- nr++;
- on_list++;
- }
- list = last;
- show_list("bisection 2 sorted", 0, nr, list);
-
- *all = nr;
- weights = xcalloc(on_list, sizeof(*weights));
-
- /* Do the real work of finding bisection commit. */
- best = do_find_bisection(list, nr, weights, find_all);
- if (best) {
- if (!find_all)
- best->next = NULL;
- *reaches = weight(best);
+ strcpy(hex, sha1_to_hex(revs->commits->item->object.sha1));
+
+ if (show_all) {
+ traverse_commit_list(revs, show_commit, show_object);
+ printf("------\n");
}
- free(weights);
- return best;
+
+ printf("bisect_rev=%s\n"
+ "bisect_nr=%d\n"
+ "bisect_good=%d\n"
+ "bisect_bad=%d\n"
+ "bisect_all=%d\n"
+ "bisect_steps=%d\n",
+ hex,
+ cnt - 1,
+ all - reaches - 1,
+ reaches - 1,
+ all,
+ estimate_bisect_steps(all));
+
+ return 0;
}
int cmd_rev_list(int argc, const char **argv, const char *prefix)
struct commit_list *list;
int i;
int read_from_stdin = 0;
+ int bisect_list = 0;
int bisect_show_vars = 0;
int bisect_find_all = 0;
int quiet = 0;
revs.commits = find_bisection(revs.commits, &reaches, &all,
bisect_find_all);
- if (bisect_show_vars) {
- int cnt;
- char hex[41];
- if (!revs.commits)
- return 1;
- /*
- * revs.commits can reach "reaches" commits among
- * "all" commits. If it is good, then there are
- * (all-reaches) commits left to be bisected.
- * On the other hand, if it is bad, then the set
- * to bisect is "reaches".
- * A bisect set of size N has (N-1) commits further
- * to test, as we already know one bad one.
- */
- cnt = all - reaches;
- if (cnt < reaches)
- cnt = reaches;
- strcpy(hex, sha1_to_hex(revs.commits->item->object.sha1));
-
- if (bisect_find_all) {
- traverse_commit_list(&revs, show_commit, show_object);
- printf("------\n");
- }
-
- printf("bisect_rev=%s\n"
- "bisect_nr=%d\n"
- "bisect_good=%d\n"
- "bisect_bad=%d\n"
- "bisect_all=%d\n",
- hex,
- cnt - 1,
- all - reaches - 1,
- reaches - 1,
- all);
- return 0;
- }
+ if (bisect_show_vars)
+ return show_bisect_vars(&revs, reaches, all,
+ bisect_find_all);
}
traverse_commit_list(&revs,