1 files changed, 137 insertions, 0 deletions
diff --git a/builtin-diff-tree.c b/builtin-diff-tree.c
new file mode 100644
index 0000000000..24cb2d7f84
--- /dev/null
+++ b/builtin-diff-tree.c
@@ -0,0 +1,137 @@
+#include "cache.h"
+#include "diff.h"
+#include "commit.h"
+#include "log-tree.h"
+#include "builtin.h"
+
+static struct rev_info log_tree_opt;
+
+static int diff_tree_commit_sha1(const unsigned char *sha1)
+{
+	struct commit *commit = lookup_commit_reference(sha1);
+	if (!commit)
+		return -1;
+	return log_tree_commit(&log_tree_opt, commit);
+}
+
+static int diff_tree_stdin(char *line)
+{
+	int len = strlen(line);
+	unsigned char sha1[20];
+	struct commit *commit;
+
+	if (!len || line[len-1] != '\n')
+		return -1;
+	line[len-1] = 0;
+	if (get_sha1_hex(line, sha1))
+		return -1;
+	commit = lookup_commit(sha1);
+	if (!commit || parse_commit(commit))
+		return -1;
+	if (isspace(line[40]) && !get_sha1_hex(line+41, sha1)) {
+		/* Graft the fake parents locally to the commit */
+		int pos = 41;
+		struct commit_list **pptr, *parents;
+
+		/* Free the real parent list */
+		for (parents = commit->parents; parents; ) {
+			struct commit_list *tmp = parents->next;
+			free(parents);
+			parents = tmp;
+		}
+		commit->parents = NULL;
+		pptr = &(commit->parents);
+		while (line[pos] && !get_sha1_hex(line + pos, sha1)) {
+			struct commit *parent = lookup_commit(sha1);
+			if (parent) {
+				pptr = &commit_list_insert(parent, pptr)->next;
+			}
+			pos += 41;
+		}
+	}
+	return log_tree_commit(&log_tree_opt, commit);
+}
+
+static const char diff_tree_usage[] =
+"git-diff-tree [--stdin] [-m] [-c] [--cc] [-s] [-v] [--pretty] [-t] [-r] [--root] "
+"[<common diff options>] <tree-ish> [<tree-ish>] [<path>...]\n"
+"  -r            diff recursively\n"
+"  --root        include the initial commit as diff against /dev/null\n"
+COMMON_DIFF_OPTIONS_HELP;
+
+int cmd_diff_tree(int argc, const char **argv, const char *prefix)
+{
+	int nr_sha1;
+	char line[1000];
+	struct object *tree1, *tree2;
+	static struct rev_info *opt = &log_tree_opt;
+	int read_stdin = 0;
+
+	init_revisions(opt, prefix);
+	git_config(git_default_config); /* no "diff" UI options */
+	nr_sha1 = 0;
+	opt->abbrev = 0;
+	opt->diff = 1;
+	argc = setup_revisions(argc, argv, opt, NULL);
+
+	while (--argc > 0) {
+		const char *arg = *++argv;
+
+		if (!strcmp(arg, "--stdin")) {
+			read_stdin = 1;
+			continue;
+		}
+		usage(diff_tree_usage);
+	}
+
+	if (!opt->diffopt.output_format)
+		opt->diffopt.output_format = DIFF_FORMAT_RAW;
+
+	/*
+	 * NOTE! We expect "a ^b" to be equal to "a..b", so we
+	 * reverse the order of the objects if the second one
+	 * is marked UNINTERESTING.
+	 */
+	nr_sha1 = opt->pending.nr;
+	switch (nr_sha1) {
+	case 0:
+		if (!read_stdin)
+			usage(diff_tree_usage);
+		break;
+	case 1:
+		tree1 = opt->pending.objects[0].item;
+		diff_tree_commit_sha1(tree1->sha1);
+		break;
+	case 2:
+		tree1 = opt->pending.objects[0].item;
+		tree2 = opt->pending.objects[1].item;
+		if (tree2->flags & UNINTERESTING) {
+			struct object *tmp = tree2;
+			tree2 = tree1;
+			tree1 = tmp;
+		}
+		diff_tree_sha1(tree1->sha1,
+			       tree2->sha1,
+			       "", &opt->diffopt);
+		log_tree_diff_flush(opt);
+		break;
+	}
+
+	if (!read_stdin)
+		return 0;
+
+	if (opt->diffopt.detect_rename)
+		opt->diffopt.setup |= (DIFF_SETUP_USE_SIZE_CACHE |
+				       DIFF_SETUP_USE_CACHE);
+	while (fgets(line, sizeof(line), stdin)) {
+		unsigned char sha1[20];
+
+		if (get_sha1_hex(line, sha1)) {
+			fputs(line, stdout);
+			fflush(stdout);
+		}
+		else
+			diff_tree_stdin(line);
+	}
+	return 0;
+}