diff-tree --cc: squelch header generation on empty patch.

Earlier round showed the commit log header and "diff --combined"
header even for paths that had no interesting hunk under --cc
flag.  Move the header display logic around to squelch them.
With this, a merge that does not have any interesting merges
will not be shown with --cc option, unless -m is used at the
same time.

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

diff --git a/combine-diff.c b/combine-diff.c
index a91cafb..3b219a0 100644 (file)
--- a/combine-diff.c
+++ b/combine-diff.c
@@ -323,12 +323,13 @@ static unsigned long line_all_diff(struct sline *sline, unsigned long all_mask)
        return different;
 }
 
-static void make_hunks(struct sline *sline, unsigned long cnt,
+static int make_hunks(struct sline *sline, unsigned long cnt,
                       int num_parent, int dense)
 {
        unsigned long all_mask = (1UL<<num_parent) - 1;
        unsigned long mark = (1UL<<num_parent);
        unsigned long i;
+       int has_interesting = 0;
 
        i = 0;
        while (i < cnt) {
@@ -344,21 +345,23 @@ static void make_hunks(struct sline *sline, unsigned long cnt,
                        j = (i + context < cnt) ? i + context : cnt;
                        while (i < j)
                                sline[i++].flag |= mark;
+                       has_interesting = 1;
                        continue;
                }
                i++;
        }
        if (!dense)
-               return;
+               return has_interesting;
 
        /* Look at each hunk, and if we have changes from only one
         * parent, or the changes are the same from all but one
         * parent, mark that uninteresting.
         */
+       has_interesting = 0;
        i = 0;
        while (i < cnt) {
                int j, hunk_end, same, diff;
-               unsigned long same_diff, all_diff, this_diff;
+               unsigned long same_diff, all_diff;
                while (i < cnt && !(sline[i].flag & mark))
                        i++;
                if (cnt <= i)
@@ -387,8 +390,11 @@ static void make_hunks(struct sline *sline, unsigned long cnt,
                        for (j = i; j < hunk_end; j++)
                                sline[j].flag &= ~mark;
                }
+               else
+                       has_interesting = 1;
                i = hunk_end;
        }
+       return has_interesting;
 }
 
 static void dump_sline(struct sline *sline, int cnt, int num_parent)
@@ -437,13 +443,13 @@ static void dump_sline(struct sline *sline, int cnt, int num_parent)
        }
 }
 
-static void show_combined_diff(struct path_list *elem, int num_parent,
-                              int dense)
+static int show_combined_diff(struct path_list *elem, int num_parent,
+                             int dense, const char *header, int show_empty)
 {
        unsigned long size, cnt, lno;
        char *result, *cp, *ep;
        struct sline *sline; /* survived lines */
-       int i;
+       int i, show_hunks, shown_header = 0;
        char ourtmp[TMPPATHLEN];
 
        /* Read the result of merge first */
@@ -479,9 +485,21 @@ static void show_combined_diff(struct path_list *elem, int num_parent,
        for (i = 0; i < num_parent; i++)
                combine_diff(elem->parent_sha1[i], ourtmp, sline, cnt, i);
 
-       make_hunks(sline, cnt, num_parent, dense);
+       show_hunks = make_hunks(sline, cnt, num_parent, dense);
 
-       dump_sline(sline, cnt, num_parent);
+       if (header && (show_hunks || show_empty)) {
+               shown_header++;
+               puts(header);
+       }
+       if (show_hunks) {
+               printf("diff --%s ", dense ? "cc" : "combined");
+               if (quote_c_style(elem->path, NULL, NULL, 0))
+                       quote_c_style(elem->path, NULL, stdout, 0);
+               else
+                       printf("%s", elem->path);
+               putchar('\n');
+               dump_sline(sline, cnt, num_parent);
+       }
        unlink(ourtmp);
        free(result);
 
@@ -496,6 +514,7 @@ static void show_combined_diff(struct path_list *elem, int num_parent,
                }
        }
        free(sline);
+       return shown_header;
 }
 
 int diff_tree_combined_merge(const unsigned char *sha1,
@@ -535,17 +554,12 @@ int diff_tree_combined_merge(const unsigned char *sha1,
                        num_paths++;
        }
        if (num_paths || show_empty_merge) {
-               puts(header);
                for (p = paths; p; p = p->next) {
                        if (!p->len)
                                continue;
-                       printf("diff --%s ", dense ? "cc" : "combined");
-                       if (quote_c_style(p->path, NULL, NULL, 0))
-                               quote_c_style(p->path, NULL, stdout, 0);
-                       else
-                               printf("%s", p->path);
-                       putchar('\n');
-                       show_combined_diff(p, num_parent, dense);
+                       if (show_combined_diff(p, num_parent, dense, header,
+                                              show_empty_merge))
+                               header = NULL;
                }
        }