diff-tree: support list if input trees on stdin

This means that you can do

	git-rev-list HEAD --max-count=10 | git-diff-tree --stdin update-cache.c

to see which (if any) of the last ten commits changed update-cache.c.

Use the "-m" flag to see merges too. Normally they are suppressed.

diff --git a/diff-tree.c b/diff-tree.c
index c689c61..9e15b70 100644 (file)
--- a/diff-tree.c
+++ b/diff-tree.c
@@ -1,7 +1,10 @@
+#include <ctype.h>
 #include "cache.h"
 #include "diff.h"
 
+static int ignore_merges = 1;
 static int recursive = 0;
+static int read_stdin = 0;
 static int line_termination = '\n';
 static int generate_patch = 0;
 
@@ -250,20 +253,67 @@ static int diff_tree_sha1(const unsigned char *old, const unsigned char *new, co
        return retval;
 }
 
+static int diff_tree_stdin(char *line)
+{
+       int len = strlen(line);
+       unsigned char commit[20], parent[20];
+       unsigned long size, offset;
+       char *buf;
+
+       if (!len || line[len-1] != '\n')
+               return -1;
+       line[len-1] = 0;
+       if (get_sha1_hex(line, commit))
+               return -1;
+       if (isspace(line[40]) && !get_sha1_hex(line+41, parent)) {
+               line[40] = ' ';
+               line[81] = 0;
+               printf("%s:\n", line);
+               return diff_tree_sha1(parent, commit, "");
+       }
+       buf = read_object_with_reference(commit, "commit", &size, NULL);
+       if (!buf)
+               return -1;
+
+       /* More than one parent? */
+       if (ignore_merges) {
+               if (!memcmp(buf + 46 + 48, "parent ", 7))
+                       return 0;
+       }
+
+       line[40] = 0;
+       offset = 46;
+       while (offset + 48 < size && !memcmp(buf + offset, "parent ", 7)) {
+               if (get_sha1_hex(buf + offset + 7, parent))
+                       return -1;
+               printf("%s %s:\n", line, sha1_to_hex(parent));
+               diff_tree_sha1(parent, commit, "");
+               offset += 48;
+       }
+       return -1;
+}
+
 static char *diff_tree_usage = "diff-tree [-p] [-r] [-z] <tree sha1> <tree sha1>";
 
 int main(int argc, char **argv)
 {
+       char line[1000];
        unsigned char old[20], new[20];
 
        for (;;) {
-               char *arg = argv[1];
+               char *arg;
 
+               argv++;
+               argc--;
+               arg = *argv;
                if (!arg || *arg != '-')
                        break;
 
-               argv++;
-               argc--;
+               if (!strcmp(arg, "-")) {
+                       argv++;
+                       argc--;
+                       break;
+               }
                if (!strcmp(arg, "-r")) {
                        recursive = 1;
                        continue;
@@ -276,21 +326,39 @@ int main(int argc, char **argv)
                        line_termination = '\0';
                        continue;
                }
+               if (!strcmp(arg, "-m")) {
+                       ignore_merges = 0;
+                       continue;
+               }
+               if (!strcmp(arg, "--stdin")) {
+                       read_stdin = 1;
+                       continue;
+               }
                usage(diff_tree_usage);
        }
 
-       if (argc < 3 || get_sha1(argv[1], old) || get_sha1(argv[2], new))
-               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 > 3) {
+       if (argc > 0) {
                int i;
 
-               paths = &argv[3];
-               nr_paths = argc - 3;
+               paths = argv;
+               nr_paths = argc;
                pathlens = xmalloc(nr_paths * sizeof(int));
                for (i=0; i<nr_paths; i++)
                        pathlens[i] = strlen(paths[i]);
        }
 
-       return diff_tree_sha1(old, new, "");
+       if (!read_stdin)
+               return diff_tree_sha1(old, new, "");
+
+       while (fgets(line, sizeof(line), stdin))
+               diff_tree_stdin(line);
+
+       return 0;
 }