diff-tree: fix and extend argument parsing

We use "--" to mark end of command line switches, not "-". Also,
allow more flexibility in the passed-in sha1 names, in that a
single sha1 uses the "commit-diff" logic that compares against
its parent(s).

diff --git a/diff-tree.c b/diff-tree.c
index 24b24dc..8cfe990 100644 (file)
--- a/diff-tree.c
+++ b/diff-tree.c
@@ -397,19 +397,29 @@ static char *diff_tree_usage =
 
 int main(int argc, char **argv)
 {
+       int nr_sha1;
        char line[1000];
-       unsigned char old[20], new[20];
+       unsigned char sha1[2][20];
 
+       nr_sha1 = 0;
        for (;;) {
                char *arg;
 
                argv++;
                argc--;
                arg = *argv;
-               if (!arg || *arg != '-')
+               if (!arg)
                        break;
 
-               if (!strcmp(arg, "-")) {
+               if (*arg != '-') {
+                       if (nr_sha1 < 2 && !get_sha1(arg, sha1[nr_sha1])) {
+                               nr_sha1++;
+                               continue;
+                       }
+                       break;
+               }
+
+               if (!strcmp(arg, "--")) {
                        argv++;
                        argc--;
                        break;
@@ -446,13 +456,6 @@ int main(int argc, char **argv)
                usage(diff_tree_usage);
        }
 
-       if (!read_stdin) {
-               if (argc < 2 || get_sha1(argv[0], old) || get_sha1(argv[1], new))
-                       usage(diff_tree_usage);
-               argv += 2;
-               argc -= 2;
-       }
-
        if (argc > 0) {
                int i;
 
@@ -463,8 +466,21 @@ int main(int argc, char **argv)
                        pathlens[i] = strlen(paths[i]);
        }
 
+       switch (nr_sha1) {
+       case 0:
+               if (!read_stdin)
+                       usage(diff_tree_usage);
+               break;
+       case 1:
+               diff_tree_commit(sha1[0], sha1_to_hex(sha1[0]));
+               break;
+       case 2:
+               diff_tree_sha1(sha1[0], sha1[1], "");
+               break;
+       }
+
        if (!read_stdin)
-               return diff_tree_sha1(old, new, "");
+               return 0;
 
        while (fgets(line, sizeof(line), stdin))
                diff_tree_stdin(line);