improve depth heuristic for maximum delta size

diff --git a/show-branch.c b/show-branch.c
index 452e63f78682c44d52f1391a74077036b786f3b5..268c57b180627f7d8ba3a3a754210a37d420fb0d 100644 (file)
--- a/show-branch.c
+++ b/show-branch.c
@@ -5,7 +5,7 @@
 #include "refs.h"
 
 static const char show_branch_usage[] =
-"git-show-branch [--current] [--all] [--heads] [--tags] [--topo-order] [--more=count | --list | --independent | --merge-base ] [--topics] [<refs>...]";
+"git-show-branch [--dense] [--current] [--all] [--heads] [--tags] [--topo-order] [--more=count | --list | --independent | --merge-base ] [--topics] [<refs>...]";
 
 static int default_num = 0;
 static int default_alloc = 0;
@@ -527,6 +527,27 @@ static int git_show_branch_config(const char *var, const char *value)
        return git_default_config(var, value);
 }
 
+static int omit_in_dense(struct commit *commit, struct commit **rev, int n)
+{
+       /* If the commit is tip of the named branches, do not
+        * omit it.
+        * Otherwise, if it is a merge that is reachable from only one
+        * tip, it is not that interesting.
+        */
+       int i, flag, count;
+       for (i = 0; i < n; i++)
+               if (rev[i] == commit)
+                       return 0;
+       flag = commit->object.flags;
+       for (i = count = 0; i < n; i++) {
+               if (flag & (1u << (i + REV_SHIFT)))
+                       count++;
+       }
+       if (count == 1)
+               return 1;
+       return 0;
+}
+
 int main(int ac, char **av)
 {
        struct commit *rev[MAX_REVS], *commit;
@@ -548,6 +569,7 @@ int main(int ac, char **av)
        int with_current_branch = 0;
        int head_at = -1;
        int topics = 0;
+       int dense = 1;
 
        setup_git_directory();
        git_config(git_show_branch_config);
@@ -590,6 +612,8 @@ int main(int ac, char **av)
                        lifo = 1;
                else if (!strcmp(arg, "--topics"))
                        topics = 1;
+               else if (!strcmp(arg, "--sparse"))
+                       dense = 0;
                else if (!strcmp(arg, "--date-order"))
                        lifo = 0;
                else
@@ -727,25 +751,20 @@ int main(int ac, char **av)
        while (seen) {
                struct commit *commit = pop_one_commit(&seen);
                int this_flag = commit->object.flags;
+               int is_merge_point = ((this_flag & all_revs) == all_revs);
 
-               shown_merge_point |= ((this_flag & all_revs) == all_revs);
+               shown_merge_point |= is_merge_point;
 
                if (1 < num_rev) {
-                       int is_merge = !!(commit->parents && commit->parents->next);
-                       if (topics) {
-                               int interesting = 0;
-                               for (i = 1; i < num_rev; i++) {
-                                       if ((this_flag &
-                                            (1u << (i + REV_SHIFT)))) {
-                                               interesting = 1;
-                                               break;
-                                       }
-                               }
-                               if (!interesting)
-                                       continue;
-                       }
-
-
+                       int is_merge = !!(commit->parents &&
+                                         commit->parents->next);
+                       if (topics &&
+                           !is_merge_point &&
+                           (this_flag & (1u << REV_SHIFT)))
+                               continue;
+                       if (dense && is_merge &&
+                           omit_in_dense(commit, rev, num_rev))
+                               continue;
                        for (i = 0; i < num_rev; i++) {
                                int mark;
                                if (!(this_flag & (1u << (i + REV_SHIFT))))