diff-tree: add "--root" flag to show a root commit as a big creation event.

"Let there be light"

diff --git a/diff-tree.c b/diff-tree.c
index d3d83bd..9d94e0c 100644 (file)
--- a/diff-tree.c
+++ b/diff-tree.c
@@ -3,6 +3,7 @@
 #include "diff.h"
 
 static int silent = 0;
+static int show_root_diff = 0;
 static int verbose_header = 0;
 static int ignore_merges = 1;
 static int recursive = 0;
@@ -294,6 +295,24 @@ static int diff_tree_sha1_top(const unsigned char *old,
        return ret;
 }
 
+static int diff_root_tree(const unsigned char *new, const char *base)
+{
+       int retval;
+       void *tree;
+       unsigned long size;
+
+       if (generate_patch)
+               diff_setup(detect_rename, 0, 0, 0, 0);
+       tree = read_object_with_reference(new, "tree", &size, 0);
+       if (!tree)
+               die("unable to read root tree (%s)", sha1_to_hex(new));
+       retval = diff_tree("", 0, tree, size, base);
+       free(tree);
+       if (generate_patch)
+               diff_flush();
+       return retval;
+}
+
 static int get_one_line(const char *msg, unsigned long len)
 {
        int ret = 0;
@@ -372,18 +391,24 @@ static int diff_tree_commit(const unsigned char *commit, const char *name)
        if (!buf)
                return -1;
 
-       /* More than one parent? */
-       if (ignore_merges) {
-               if (!memcmp(buf + 46 + 48, "parent ", 7))
-                       return 0;
-       }
-
        if (!name) {
                static char commit_name[60];
                strcpy(commit_name, sha1_to_hex(commit));
                name = commit_name;
        }
 
+       /* Root commit? */
+       if (show_root_diff && memcmp(buf + 46, "parent ", 7)) {
+               header = generate_header(name, "root", buf, size);
+               diff_root_tree(commit, "");
+       }
+
+       /* More than one parent? */
+       if (ignore_merges) {
+               if (!memcmp(buf + 46 + 48, "parent ", 7))
+                       return 0;
+       }
+
        offset = 46;
        while (offset + 48 < size && !memcmp(buf + offset, "parent ", 7)) {
                unsigned char parent[20];
@@ -485,6 +510,10 @@ int main(int argc, char **argv)
                        read_stdin = 1;
                        continue;
                }
+               if (!strcmp(arg, "--root")) {
+                       show_root_diff = 1;
+                       continue;
+               }
                usage(diff_tree_usage);
        }