1 files changed, 46 insertions, 47 deletions

diff --git a/builtin/diff-tree.c b/builtin/diff-tree.c
index 806dd7a885..31d2cb4107 100644
--- a/builtin/diff-tree.c
+++ b/builtin/diff-tree.c
@@ -1,4 +1,5 @@
 #include "cache.h"
+#include "config.h"
 #include "diff.h"
 #include "commit.h"
 #include "log-tree.h"
@@ -7,52 +8,50 @@
 
 static struct rev_info log_tree_opt;
 
-static int diff_tree_commit_sha1(const unsigned char *sha1)
+static int diff_tree_commit_oid(const struct object_id *oid)
 {
-	struct commit *commit = lookup_commit_reference(sha1);
+	struct commit *commit = lookup_commit_reference(oid);
 	if (!commit)
 		return -1;
 	return log_tree_commit(&log_tree_opt, commit);
 }
 
 /* Diff one or more commits. */
-static int stdin_diff_commit(struct commit *commit, char *line, int len)
+static int stdin_diff_commit(struct commit *commit, const char *p)
 {
-	unsigned char sha1[20];
-	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;
-
-		/* Free the real parent list */
-		free_commit_list(commit->parents);
-		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;
+	struct object_id oid;
+	struct commit_list **pptr = NULL;
+
+	/* Graft the fake parents locally to the commit */
+	while (isspace(*p++) && !parse_oid_hex(p, &oid, &p)) {
+		struct commit *parent = lookup_commit(&oid);
+		if (!pptr) {
+			/* Free the real parent list */
+			free_commit_list(commit->parents);
+			commit->parents = NULL;
+			pptr = &(commit->parents);
+		}
+		if (parent) {
+			pptr = &commit_list_insert(parent, pptr)->next;
 		}
 	}
 	return log_tree_commit(&log_tree_opt, commit);
 }
 
 /* Diff two trees. */
-static int stdin_diff_trees(struct tree *tree1, char *line, int len)
+static int stdin_diff_trees(struct tree *tree1, const char *p)
 {
-	unsigned char sha1[20];
+	struct object_id oid;
 	struct tree *tree2;
-	if (len != 82 || !isspace(line[40]) || get_sha1_hex(line + 41, sha1))
+	if (!isspace(*p++) || parse_oid_hex(p, &oid, &p) || *p)
 		return error("Need exactly two trees, separated by a space");
-	tree2 = lookup_tree(sha1);
+	tree2 = lookup_tree(&oid);
 	if (!tree2 || parse_tree(tree2))
 		return -1;
 	printf("%s %s\n", oid_to_hex(&tree1->object.oid),
 			  oid_to_hex(&tree2->object.oid));
-	diff_tree_sha1(tree1->object.oid.hash, tree2->object.oid.hash,
-		       "", &log_tree_opt.diffopt);
+	diff_tree_oid(&tree1->object.oid, &tree2->object.oid,
+		      "", &log_tree_opt.diffopt);
 	log_tree_diff_flush(&log_tree_opt);
 	return 0;
 }
@@ -60,23 +59,24 @@ static int stdin_diff_trees(struct tree *tree1, char *line, int len)
 static int diff_tree_stdin(char *line)
 {
 	int len = strlen(line);
-	unsigned char sha1[20];
+	struct object_id oid;
 	struct object *obj;
+	const char *p;
 
 	if (!len || line[len-1] != '\n')
 		return -1;
 	line[len-1] = 0;
-	if (get_sha1_hex(line, sha1))
+	if (parse_oid_hex(line, &oid, &p))
 		return -1;
-	obj = parse_object(sha1);
+	obj = parse_object(&oid);
 	if (!obj)
 		return -1;
 	if (obj->type == OBJ_COMMIT)
-		return stdin_diff_commit((struct commit *)obj, line, len);
+		return stdin_diff_commit((struct commit *)obj, p);
 	if (obj->type == OBJ_TREE)
-		return stdin_diff_trees((struct tree *)obj, line, len);
+		return stdin_diff_trees((struct tree *)obj, p);
 	error("Object %s is a %s, not a commit or tree",
-	      sha1_to_hex(sha1), typename(obj->type));
+	      oid_to_hex(&oid), typename(obj->type));
 	return -1;
 }
 
@@ -99,16 +99,18 @@ static void diff_tree_tweak_rev(struct rev_info *rev, struct setup_revision_opt
 
 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;
 	struct setup_revision_opt s_r_opt;
 	int read_stdin = 0;
 
+	if (argc == 2 && !strcmp(argv[1], "-h"))
+		usage(diff_tree_usage);
+
+	git_config(git_diff_basic_config, NULL); /* no "diff" UI options */
 	init_revisions(opt, prefix);
 	gitmodules_config();
-	git_config(git_diff_basic_config, NULL); /* no "diff" UI options */
 	opt->abbrev = 0;
 	opt->diff = 1;
 	opt->disable_stdin = 1;
@@ -129,31 +131,28 @@ int cmd_diff_tree(int argc, const char **argv, const char *prefix)
 	}
 
 	/*
-	 * 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.
+	 * NOTE!  We expect "a..b" to expand to "^a b" but it is
+	 * perfectly valid for revision range parser to yield "b ^a",
+	 * which means the same thing. If we get the latter, i.e. the
+	 * second one is marked UNINTERESTING, we recover the original
+	 * order the user gave, i.e. "a..b", by swapping the trees.
 	 */
-	nr_sha1 = opt->pending.nr;
-	switch (nr_sha1) {
+	switch (opt->pending.nr) {
 	case 0:
 		if (!read_stdin)
 			usage(diff_tree_usage);
 		break;
 	case 1:
 		tree1 = opt->pending.objects[0].item;
-		diff_tree_commit_sha1(tree1->oid.hash);
+		diff_tree_commit_oid(&tree1->oid);
 		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;
+			SWAP(tree2, tree1);
 		}
-		diff_tree_sha1(tree1->oid.hash,
-			       tree2->oid.hash,
-			       "", &opt->diffopt);
+		diff_tree_oid(&tree1->oid, &tree2->oid, "", &opt->diffopt);
 		log_tree_diff_flush(opt);
 		break;
 	}
@@ -166,9 +165,9 @@ int cmd_diff_tree(int argc, const char **argv, const char *prefix)
 			opt->diffopt.setup |= (DIFF_SETUP_USE_SIZE_CACHE |
 					       DIFF_SETUP_USE_CACHE);
 		while (fgets(line, sizeof(line), stdin)) {
-			unsigned char sha1[20];
+			struct object_id oid;
 
-			if (get_sha1_hex(line, sha1)) {
+			if (get_oid_hex(line, &oid)) {
 				fputs(line, stdout);
 				fflush(stdout);
 			}