Teach core object handling functions about gitlinks
[gitweb.git] / builtin-rev-list.c
index 7075548e6b4d5e1c3c899e033339202d46726358..09774f9559b81050d89bd6663b8b672438da4342 100644 (file)
@@ -35,6 +35,7 @@ static const char rev_list_usage[] =
 "    --header | --pretty\n"
 "    --abbrev=nr | --no-abbrev\n"
 "    --abbrev-commit\n"
+"    --left-right\n"
 "  special purpose:\n"
 "    --bisect\n"
 "    --bisect-vars"
@@ -169,51 +170,7 @@ static void clear_distance(struct commit_list *list)
        }
 }
 
-static struct commit_list *find_bisection(struct commit_list *list,
-                                         int *reaches, int *all)
-{
-       int nr, closest;
-       struct commit_list *p, *best;
-
-       nr = 0;
-       p = list;
-       while (p) {
-               if (!revs.prune_fn || (p->item->object.flags & TREECHANGE))
-                       nr++;
-               p = p->next;
-       }
-       closest = -1;
-       best = list;
-       *all = nr;
-
-       for (p = list; p; p = p->next) {
-               int distance, reach;
-
-               if (revs.prune_fn && !(p->item->object.flags & TREECHANGE))
-                       continue;
-
-               distance = reach = count_distance(p);
-               clear_distance(list);
-               if (nr - distance < distance)
-                       distance = nr - distance;
-               if (distance > closest) {
-                       best = p;
-                       *reaches = reach;
-                       closest = distance;
-               }
-       }
-       if (best)
-               best->next = NULL;
-       return best;
-}
-
-static inline int commit_interesting(struct commit_list *elem)
-{
-       unsigned flags = elem->item->object.flags;
-       if (flags & UNINTERESTING)
-               return 0;
-       return (!revs.prune_fn || (flags & TREECHANGE));
-}
+#define DEBUG_BISECT 0
 
 static inline int weight(struct commit_list *elem)
 {
@@ -225,16 +182,17 @@ static inline void weight_set(struct commit_list *elem, int weight)
        *((int*)(elem->item->util)) = weight;
 }
 
-static int count_interesting_parents(struct commit_list *elem)
+static int count_interesting_parents(struct commit *commit)
 {
-       int cnt = 0;
-       if (!elem->item->parents)
-               return cnt;
-       for (elem = elem->item->parents; elem; elem = elem->next) {
-               if (commit_interesting(elem))
-                       cnt++;
+       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 cnt;
+       return count;
 }
 
 static inline int halfway(struct commit_list *p, int distance, int nr)
@@ -244,7 +202,8 @@ static inline int halfway(struct commit_list *p, int distance, int nr)
         */
        if (revs.prune_fn && !(p->item->object.flags & TREECHANGE))
                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.
@@ -258,49 +217,127 @@ static inline int halfway(struct commit_list *p, int distance, int nr)
        }
 }
 
-static struct commit_list *find_bisection_2(struct commit_list *list,
-                                           int *reaches, int *all)
+#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)
 {
-       int n, nr, counted, distance;
-       struct commit_list *p, *best;
+       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 & TREECHANGE) ? '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 */
+
+/*
+ * 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).
+ *
+ * weight = -1 means it has one parent and its distance is yet to
+ * be computed.
+ *
+ * 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.
+ */
+
+static struct commit_list *find_bisection(struct commit_list *list,
+                                         int *reaches, int *all)
+{
+       int n, nr, on_list, counted, distance;
+       struct commit_list *p, *best, *next, *last;
        int *weights;
 
-       for (nr = 0, p = list; p; p = p->next) {
-               if (commit_interesting(p))
+       show_list("bisection 2 entry", 0, 0, list);
+
+       /*
+        * Count the number of total and tree-changing items on the
+        * list, while reversing the list.
+        */
+       for (nr = on_list = 0, last = NULL, p = list;
+            p;
+            p = next) {
+               unsigned flags = p->item->object.flags;
+
+               next = p->next;
+               if (flags & UNINTERESTING)
+                       continue;
+               p->next = last;
+               last = p;
+               if (!revs.prune_fn || (flags & TREECHANGE))
                        nr++;
+               on_list++;
        }
+       list = last;
+       show_list("bisection 2 sorted", 0, nr, list);
+
        *all = nr;
-       weights = xcalloc(nr, sizeof(int*));
+       weights = xcalloc(on_list, sizeof(int*));
        counted = 0;
 
        for (n = 0, p = list; p; p = p->next) {
-               if (!commit_interesting(p))
-                       continue;
-               if (commit_interesting(p)) {
-                       /*
-                        * positive weight is the number of interesting
-                        * commits it can reach, including itself.
-                        * weight = 0 means it has one parent and
-                        * its distance is unknown.
-                        * weight < 0 means it has more than one
-                        * parent and its distance is unknown.
-                        */
-                       p->item->util = &weights[n++];
-                       switch (count_interesting_parents(p)) {
-                       case 0:
+               struct commit *commit = p->item;
+               unsigned flags = commit->object.flags;
+
+               p->item->util = &weights[n++];
+               switch (count_interesting_parents(commit)) {
+               case 0:
+                       if (!revs.prune_fn || (flags & TREECHANGE)) {
                                weight_set(p, 1);
                                counted++;
-                               break;
-                       case 1:
-                               weight_set(p, 0);
-                               break;
-                       default:
-                               weight_set(p, -1);
-                               break;
+                               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
@@ -316,13 +353,13 @@ static struct commit_list *find_bisection_2(struct commit_list *list,
         * way, and then fill the blanks using cheaper algorithm.
         */
        for (p = list; p; p = p->next) {
-               if (!commit_interesting(p))
+               if (p->item->object.flags & UNINTERESTING)
                        continue;
                n = weight(p);
-               if (0 <= n)
+               if (n != -2)
                        continue;
                distance = count_distance(p);
-               clear_distance(p);
+               clear_distance(list);
                weight_set(p, distance);
 
                /* Does it happen to be at exactly half-way? */
@@ -335,19 +372,37 @@ static struct commit_list *find_bisection_2(struct commit_list *list,
                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 (!commit_interesting(p) || 0 < weight(p))
+                       if (0 <= weight(p))
                                continue;
-                       for (q = p->item->parents; q; q = q->next)
-                               if (commit_interesting(q) && 0 < weight(q))
+                       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_set(p, weight(q)+1);
-                       counted++;
+
+                       /*
+                        * 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 (!revs.prune_fn || (flags & TREECHANGE)) {
+                               weight_set(p, weight(q)+1);
+                               counted++;
+                               show_list("bisection 2 count one",
+                                         counted, nr, list);
+                       }
+                       else
+                               weight_set(p, weight(q));
 
                        /* Does it happen to be at exactly half-way? */
                        distance = weight(p);
@@ -360,11 +415,15 @@ static struct commit_list *find_bisection_2(struct commit_list *list,
                }
        }
 
+       show_list("bisection 2 counted all", counted, nr, list);
+
        /* Then find the best one */
-       counted = 0;
+       counted = -1;
        best = list;
        for (p = list; p; p = p->next) {
-               if (!commit_interesting(p))
+               unsigned flags = p->item->object.flags;
+
+               if (revs.prune_fn && !(flags & TREECHANGE))
                        continue;
                distance = weight(p);
                if (nr - distance < distance)
@@ -472,12 +531,7 @@ int cmd_rev_list(int argc, const char **argv, const char *prefix)
        if (bisect_list) {
                int reaches = reaches, all = all;
 
-               if (!revs.prune_fn)
-                       revs.commits = find_bisection_2(revs.commits,
-                                                       &reaches, &all);
-               else
-                       revs.commits = find_bisection(revs.commits,
-                                                     &reaches, &all);
+               revs.commits = find_bisection(revs.commits, &reaches, &all);
                if (bisect_show_vars) {
                        int cnt;
                        if (!revs.commits)