show-branch: --list and --independent

The --list option is what 'git branch' without parameter should
have been; it shows the one-line commit message for each branch
name.  The --independent option is used to filter out commits
that can be reachable from other commits, to make detection of
fast forward condition in multi-head merge easier.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/Documentation/git-show-branch.txt b/Documentation/git-show-branch.txt
index cc7da30..39e0682 100644 (file)
--- a/Documentation/git-show-branch.txt
+++ b/Documentation/git-show-branch.txt
@@ -8,7 +8,7 @@ git-show-branch - Show branches and their commits.
 
 SYNOPSIS
 --------
-'git show-branch [--all] [--heads] [--tags] [--more=<n>] [--merge-base] <reference>...'
+'git show-branch [--all] [--heads] [--tags] [--more=<n> | --list | --independent | --merge-base] <reference>...'
 
 DESCRIPTION
 -----------
@@ -29,13 +29,25 @@ OPTIONS
        Usually the command stops output upon showing the commit
        that is the common ancestor of all the branches.  This
        flag tells the command to go <n> more common commits
-       beyond that.
+       beyond that.  When <n> is negative, display only the
+       <reference>s given, without showing the commit ancestry
+       tree.
+
+--list::
+       Synomym to `--more=-1`
 
 --merge-base::
        Instead of showing the commit list, just act like the
        'git-merge-base -a' command, except that it can accept
        more than two heads.
 
+--independent::
+       Among the <reference>s given, display only the ones that
+       cannot be reached from any other <reference>.
+
+Note that --more, --list, --independent and --merge-base options
+are mutually exclusive.
+
 
 OUTPUT
 ------

diff --git a/show-branch.c b/show-branch.c
index ccb0c73..c117c53 100644 (file)
--- a/show-branch.c
+++ b/show-branch.c
@@ -4,7 +4,7 @@
 #include "refs.h"
 
 static const char show_branch_usage[] =
-"git-show-branch [--all] [--heads] [--tags] [--more=count] [--merge-base] [<refs>...]";
+"git-show-branch [--all] [--heads] [--tags] [--more=count | --list | --independent | --merge-base ] [<refs>...]";
 
 #define UNINTERESTING  01
 
@@ -306,10 +306,29 @@ static int show_merge_base(struct commit_list *seen, int num_rev)
        return exit_status;
 }
 
+static int show_independent(struct commit **rev,
+                           int num_rev,
+                           char **ref_name,
+                           unsigned int *rev_mask)
+{
+       int i;
+
+       for (i = 0; i < num_rev; i++) {
+               struct commit *commit = rev[i];
+               unsigned int flag = rev_mask[i];
+
+               if (commit->object.flags == flag)
+                       puts(sha1_to_hex(commit->object.sha1));
+               commit->object.flags |= UNINTERESTING;
+       }
+       return 0;
+}
+
 int main(int ac, char **av)
 {
        struct commit *rev[MAX_REVS], *commit;
        struct commit_list *list = NULL, *seen = NULL;
+       unsigned int rev_mask[MAX_REVS];
        int num_rev, i, extra = 0;
        int all_heads = 0, all_tags = 0;
        int all_mask, all_revs, shown_merge_point;
@@ -317,6 +336,7 @@ int main(int ac, char **av)
        int head_path_len;
        unsigned char head_sha1[20];
        int merge_base = 0;
+       int independent = 0;
        char **label;
 
        setup_git_directory();
@@ -331,19 +351,24 @@ int main(int ac, char **av)
                        all_tags = 1;
                else if (!strcmp(arg, "--more"))
                        extra = 1;
-               else if (!strncmp(arg, "--more=", 7)) {
+               else if (!strcmp(arg, "--list"))
+                       extra = -1;
+               else if (!strncmp(arg, "--more=", 7))
                        extra = atoi(arg + 7);
-                       if (extra < 0)
-                               usage(show_branch_usage);
-               }
                else if (!strcmp(arg, "--merge-base"))
                        merge_base = 1;
+               else if (!strcmp(arg, "--independent"))
+                       independent = 1;
                else
                        usage(show_branch_usage);
                ac--; av++;
        }
        ac--; av++;
 
+       /* Only one of these is allowed */
+       if (1 < independent + merge_base + (extra != 0))
+               usage(show_branch_usage);
+
        if (all_heads + all_tags)
                snarf_refs(all_heads, all_tags);
 
@@ -361,6 +386,7 @@ int main(int ac, char **av)
 
        for (num_rev = 0; ref_name[num_rev]; num_rev++) {
                unsigned char revkey[20];
+               unsigned int flag = 1u << (num_rev + REV_SHIFT);
 
                if (MAX_REVS <= num_rev)
                        die("cannot handle more than %d revs.", MAX_REVS);
@@ -377,11 +403,16 @@ int main(int ac, char **av)
                 * and so on.  REV_SHIFT bits from bit 0 are used for
                 * internal bookkeeping.
                 */
-               commit->object.flags |= 1u << (num_rev + REV_SHIFT);
-               insert_by_date(commit, &list);
+               commit->object.flags |= flag;
+               if (commit->object.flags == flag)
+                       insert_by_date(commit, &list);
                rev[num_rev] = commit;
        }
-       join_revs(&list, &seen, num_rev, extra);
+       for (i = 0; i < num_rev; i++)
+               rev_mask[i] = rev[i]->object.flags;
+
+       if (0 <= extra)
+               join_revs(&list, &seen, num_rev, extra);
 
        head_path_len = readlink(".git/HEAD", head_path, sizeof(head_path)-1);
        if ((head_path_len < 0) || get_sha1("HEAD", head_sha1))
@@ -392,7 +423,10 @@ int main(int ac, char **av)
        if (merge_base)
                return show_merge_base(seen, num_rev);
 
-       /* Show list */
+       if (independent)
+               return show_independent(rev, num_rev, ref_name, rev_mask);
+
+       /* Show list; --more=-1 means list-only */
        if (1 < num_rev) {
                for (i = 0; i < num_rev; i++) {
                        int j;
@@ -401,15 +435,25 @@ int main(int ac, char **av)
                                                  ref_name[i],
                                                  head_sha1,
                                                  rev[i]->object.sha1);
-                       for (j = 0; j < i; j++)
-                               putchar(' ');
-                       printf("%c [%s] ", is_head ? '*' : '!', ref_name[i]);
+                       if (extra < 0)
+                               printf("%c [%s] ",
+                                      is_head ? '*' : ' ', ref_name[i]);
+                       else {
+                               for (j = 0; j < i; j++)
+                                       putchar(' ');
+                               printf("%c [%s] ",
+                                      is_head ? '*' : '!', ref_name[i]);
+                       }
                        show_one_commit(rev[i]);
                }
-               for (i = 0; i < num_rev; i++)
-                       putchar('-');
-               putchar('\n');
+               if (0 <= extra) {
+                       for (i = 0; i < num_rev; i++)
+                               putchar('-');
+                       putchar('\n');
+               }
        }
+       if (extra < 0)
+               exit(0);
 
        /* Sort topologically */
        sort_in_topological_order(&seen);