1diff a/Documentation/git-ls-tree.txt b/Documentation/git-ls-tree.txt
2--- a/Documentation/git-ls-tree.txt
3+++ b/Documentation/git-ls-tree.txt
4@@ -4,23 +4,26 @@ v0.1, May 2005
5
6 NAME
7 ----
8-git-ls-tree - Displays a tree object in human readable form
9+git-ls-tree - Lists the contents of a tree object.
10
11
12 SYNOPSIS
13 --------
14-'git-ls-tree' [-r] [-z] <tree-ish> [paths...]
15+'git-ls-tree' [-d] [-r] [-z] <tree-ish> [paths...]
16
17 DESCRIPTION
18 -----------
19-Converts the tree object to a human readable (and script processable)
20-form.
21+Lists the contents of a tree object, like what "/bin/ls -a" does
22+in the current working directory.
23
24 OPTIONS
25 -------
26 <tree-ish>::
27 	Id of a tree.
28
29+-d::
30+	show only the named tree entry itself, not its children
31+
32 -r::
33 	recurse into sub-trees
34
35@@ -28,18 +31,19 @@ OPTIONS
36 	\0 line termination on output
37
38 paths::
39-	Optionally, restrict the output of git-ls-tree to specific
40-	paths. Directories will only list their tree blob ids.
41-	Implies -r.
42+	When paths are given, shows them.  Otherwise implicitly
43+	uses the root level of the tree as the sole path argument.
44+
45
46 Output Format
47 -------------
48-        <mode>\t	<type>\t	<object>\t	<file>
49+        <mode> SP <type> SP <object> TAB <file>
50
51
52 Author
53 ------
54 Written by Linus Torvalds <torvalds@osdl.org>
55+Completely rewritten from scratch by Junio C Hamano <junkio@cox.net>
56
57 Documentation
58 --------------
59diff a/ls-tree.c b/ls-tree.c
60--- a/ls-tree.c
61+++ b/ls-tree.c
62@@ -4,188 +4,217 @@
63  * Copyright (C) Linus Torvalds, 2005
64  */
65 #include "cache.h"
66+#include "blob.h"
67+#include "tree.h"
68
69 static int line_termination = '\n';
70-static int recursive = 0;
71+#define LS_RECURSIVE 1
72+#define LS_TREE_ONLY 2
73+static int ls_options = 0;
74
75-struct path_prefix {
76-	struct path_prefix *prev;
77-	const char *name;
78-};
79-
80-#define DEBUG(fmt, ...)
81-
82-static int string_path_prefix(char *buff, size_t blen, struct path_prefix *prefix)
83-{
84-	int len = 0;
85-	if (prefix) {
86-		if (prefix->prev) {
87-			len = string_path_prefix(buff,blen,prefix->prev);
88-			buff += len;
89-			blen -= len;
90-			if (blen > 0) {
91-				*buff = '/';
92-				len++;
93-				buff++;
94-				blen--;
95-			}
96-		}
97-		strncpy(buff,prefix->name,blen);
98-		return len + strlen(prefix->name);
99-	}
100+static struct tree_entry_list root_entry;
101
102-	return 0;
103+static void prepare_root(unsigned char *sha1)
104+{
105+	unsigned char rsha[20];
106+	unsigned long size;
107+	void *buf;
108+	struct tree *root_tree;
109+
110+	buf = read_object_with_reference(sha1, "tree", &size, rsha);
111+	free(buf);
112+	if (!buf)
113+		die("Could not read %s", sha1_to_hex(sha1));
114+
115+	root_tree = lookup_tree(rsha);
116+	if (!root_tree)
117+		die("Could not read %s", sha1_to_hex(sha1));
118+
119+	/* Prepare a fake entry */
120+	root_entry.directory = 1;
121+	root_entry.executable = root_entry.symlink = 0;
122+	root_entry.mode = S_IFDIR;
123+	root_entry.name = "";
124+	root_entry.item.tree = root_tree;
125+	root_entry.parent = NULL;
126 }
127
128-static void print_path_prefix(struct path_prefix *prefix)
129+static int prepare_children(struct tree_entry_list *elem)
130 {
131-	if (prefix) {
132-		if (prefix->prev) {
133-			print_path_prefix(prefix->prev);
134-			putchar('/');
135-		}
136-		fputs(prefix->name, stdout);
137+	if (!elem->directory)
138+		return -1;
139+	if (!elem->item.tree->object.parsed) {
140+		struct tree_entry_list *e;
141+		if (parse_tree(elem->item.tree))
142+			return -1;
143+		/* Set up the parent link */
144+		for (e = elem->item.tree->entries; e; e = e->next)
145+			e->parent = elem;
146 	}
147+	return 0;
148 }
149
150-/*
151- * return:
152- * 	-1 if prefix is *not* a subset of path
153- * 	 0 if prefix == path
154- * 	 1 if prefix is a subset of path
155- */
156-static int pathcmp(const char *path, struct path_prefix *prefix)
157-{
158-	char buff[PATH_MAX];
159-	int len,slen;
160+static struct tree_entry_list *find_entry_0(struct tree_entry_list *elem,
161+					    const char *path,
162+					    const char *path_end)
163+{
164+	const char *ep;
165+	int len;
166+
167+	while (path < path_end) {
168+		if (prepare_children(elem))
169+			return NULL;
170
171-	if (prefix == NULL)
172-		return 1;
173+		/* In elem->tree->entries, find the one that has name
174+		 * that matches what is between path and ep.
175+		 */
176+		elem = elem->item.tree->entries;
177
178-	len = string_path_prefix(buff, sizeof buff, prefix);
179-	slen = strlen(path);
180+		ep = strchr(path, '/');
181+		if (!ep || path_end <= ep)
182+			ep = path_end;
183+		len = ep - path;
184+
185+		while (elem) {
186+			if ((strlen(elem->name) == len) &&
187+			    !strncmp(elem->name, path, len))
188+				break;
189+			elem = elem->next;
190+		}
191+		if (path_end <= ep || !elem)
192+			return elem;
193+		while (*ep == '/' && ep < path_end)
194+			ep++;
195+		path = ep;
196+	}
197+	return NULL;
198+}
199
200-	if (slen < len)
201-		return -1;
202+static struct tree_entry_list *find_entry(const char *path,
203+					  const char *path_end)
204+{
205+	/* Find tree element, descending from root, that
206+	 * corresponds to the named path, lazily expanding
207+	 * the tree if possible.
208+	 */
209+	if (path == path_end) {
210+		/* Special.  This is the root level */
211+		return &root_entry;
212+	}
213+	return find_entry_0(&root_entry, path, path_end);
214+}
215
216-	if (strncmp(path,buff,len) == 0) {
217-		if (slen == len)
218-			return 0;
219-		else
220-			return 1;
221+static void show_entry_name(struct tree_entry_list *e)
222+{
223+	/* This is yucky.  The root level is there for
224+	 * our convenience but we really want to do a
225+	 * forest.
226+	 */
227+	if (e->parent && e->parent != &root_entry) {
228+		show_entry_name(e->parent);
229+		putchar('/');
230 	}
231+	printf("%s", e->name);
232+}
233
234-	return -1;
235-}
236+static const char *entry_type(struct tree_entry_list *e)
237+{
238+	return (e->directory ? "tree" : "blob");
239+}
240
241-/*
242- * match may be NULL, or a *sorted* list of paths
243- */
244-static void list_recursive(void *buffer,
245-			   const char *type,
246-			   unsigned long size,
247-			   struct path_prefix *prefix,
248-			   char **match, int matches)
249-{
250-	struct path_prefix this_prefix;
251-	this_prefix.prev = prefix;
252-
253-	if (strcmp(type, "tree"))
254-		die("expected a 'tree' node");
255-
256-	if (matches)
257-		recursive = 1;
258-
259-	while (size) {
260-		int namelen = strlen(buffer)+1;
261-		void *eltbuf = NULL;
262-		char elttype[20];
263-		unsigned long eltsize;
264-		unsigned char *sha1 = buffer + namelen;
265-		char *path = strchr(buffer, ' ') + 1;
266-		unsigned int mode;
267-		const char *matched = NULL;
268-		int mtype = -1;
269-		int mindex;
270-
271-		if (size < namelen + 20 || sscanf(buffer, "%o", &mode) != 1)
272-			die("corrupt 'tree' file");
273-		buffer = sha1 + 20;
274-		size -= namelen + 20;
275-
276-		this_prefix.name = path;
277-		for ( mindex = 0; mindex < matches; mindex++) {
278-			mtype = pathcmp(match[mindex],&this_prefix);
279-			if (mtype >= 0) {
280-				matched = match[mindex];
281-				break;
282-			}
283-		}
284+static const char *entry_hex(struct tree_entry_list *e)
285+{
286+	return sha1_to_hex(e->directory
287+			   ? e->item.tree->object.sha1
288+			   : e->item.blob->object.sha1);
289+}
290
291-		/*
292-		 * If we're not matching, or if this is an exact match,
293-		 * print out the info
294-		 */
295-		if (!matches || (matched != NULL && mtype == 0)) {
296-			printf("%06o %s %s\t", mode,
297-			       S_ISDIR(mode) ? "tree" : "blob",
298-			       sha1_to_hex(sha1));
299-			print_path_prefix(&this_prefix);
300-			putchar(line_termination);
301-		}
302+/* forward declaration for mutually recursive routines */
303+static int show_entry(struct tree_entry_list *, int);
304
305-		if (! recursive || ! S_ISDIR(mode))
306-			continue;
307+static int show_children(struct tree_entry_list *e, int level)
308+{
309+	if (prepare_children(e))
310+		die("internal error: ls-tree show_children called with non tree");
311+	e = e->item.tree->entries;
312+	while (e) {
313+		show_entry(e, level);
314+		e = e->next;
315+	}
316+	return 0;
317+}
318
319-		if (matches && ! matched)
320-			continue;
321+static int show_entry(struct tree_entry_list *e, int level)
322+{
323+	int err = 0;
324
325-		if (! (eltbuf = read_sha1_file(sha1, elttype, &eltsize)) ) {
326-			error("cannot read %s", sha1_to_hex(sha1));
327-			continue;
328-		}
329+	if (e != &root_entry) {
330+		printf("%06o %s %s	", e->mode, entry_type(e),
331+		       entry_hex(e));
332+		show_entry_name(e);
333+		putchar(line_termination);
334+	}
335
336-		/* If this is an exact directory match, we may have
337-		 * directory files following this path. Match on them.
338-		 * Otherwise, we're at a patch subcomponent, and we need
339-		 * to try to match again.
340+	if (e->directory) {
341+		/* If this is a directory, we have the following cases:
342+		 * (1) This is the top-level request (explicit path from the
343+		 *     command line, or "root" if there is no command line).
344+		 *  a. Without any flag.  We show direct children.  We do not
345+		 *     recurse into them.
346+		 *  b. With -r.  We do recurse into children.
347+		 *  c. With -d.  We do not recurse into children.
348+		 * (2) We came here because our caller is either (1-a) or
349+		 *     (1-b).
350+		 *  a. Without any flag.  We do not show our children (which
351+		 *     are grandchildren for the original request).
352+		 *  b. With -r.  We continue to recurse into our children.
353+		 *  c. With -d.  We should not have come here to begin with.
354 		 */
355-		if (mtype == 0)
356-			mindex++;
357-
358-		list_recursive(eltbuf, elttype, eltsize, &this_prefix, &match[mindex], matches-mindex);
359-		free(eltbuf);
360+		if (level == 0 && !(ls_options & LS_TREE_ONLY))
361+			/* case (1)-a and (1)-b */
362+			err = err | show_children(e, level+1);
363+		else if (level && ls_options & LS_RECURSIVE)
364+			/* case (2)-b */
365+			err = err | show_children(e, level+1);
366 	}
367+	return err;
368 }
369
370-static int qcmp(const void *a, const void *b)
371+static int list_one(const char *path, const char *path_end)
372 {
373-	return strcmp(*(char **)a, *(char **)b);
374+	int err = 0;
375+	struct tree_entry_list *e = find_entry(path, path_end);
376+	if (!e) {
377+		/* traditionally ls-tree does not complain about
378+		 * missing path.  We may change this later to match
379+		 * what "/bin/ls -a" does, which is to complain.
380+		 */
381+		return err;
382+	}
383+	err = err | show_entry(e, 0);
384+	return err;
385 }
386
387-static int list(unsigned char *sha1,char **path)
388+static int list(char **path)
389 {
390-	void *buffer;
391-	unsigned long size;
392-	int npaths;
393-
394-	for (npaths = 0; path[npaths] != NULL; npaths++)
395-		;
396-
397-	qsort(path,npaths,sizeof(char *),qcmp);
398-
399-	buffer = read_object_with_reference(sha1, "tree", &size, NULL);
400-	if (!buffer)
401-		die("unable to read sha1 file");
402-	list_recursive(buffer, "tree", size, NULL, path, npaths);
403-	free(buffer);
404-	return 0;
405+	int i;
406+	int err = 0;
407+	for (i = 0; path[i]; i++) {
408+		int len = strlen(path[i]);
409+		while (0 <= len && path[i][len] == '/')
410+			len--;
411+		err = err | list_one(path[i], path[i] + len);
412+	}
413+	return err;
414 }
415
416-static const char *ls_tree_usage = "git-ls-tree [-r] [-z] <key> [paths...]";
417+static const char *ls_tree_usage =
418+	"git-ls-tree [-d] [-r] [-z] <tree-ish> [path...]";
419
420 int main(int argc, char **argv)
421 {
422+	static char *path0[] = { "", NULL };
423+	char **path;
424 	unsigned char sha1[20];
425
426 	while (1 < argc && argv[1][0] == '-') {
427@@ -194,7 +223,10 @@ int main(int argc, char **argv)
428 			line_termination = 0;
429 			break;
430 		case 'r':
431-			recursive = 1;
432+			ls_options |= LS_RECURSIVE;
433+			break;
434+		case 'd':
435+			ls_options |= LS_TREE_ONLY;
436 			break;
437 		default:
438 			usage(ls_tree_usage);
439@@ -206,7 +238,10 @@ int main(int argc, char **argv)
440 		usage(ls_tree_usage);
441 	if (get_sha1(argv[1], sha1) < 0)
442 		usage(ls_tree_usage);
443-	if (list(sha1, &argv[2]) < 0)
444+
445+	path = (argc == 2) ? path0 : (argv + 2);
446+	prepare_root(sha1);
447+	if (list(path) < 0)
448 		die("list failed");
449 	return 0;
450 }
451diff a/t/t3100-ls-tree-restrict.sh b/t/t3100-ls-tree-restrict.sh
452--- a/t/t3100-ls-tree-restrict.sh
453+++ b/t/t3100-ls-tree-restrict.sh
454@@ -74,8 +74,8 @@ test_expect_success \
455     'ls-tree filtered' \
456     'git-ls-tree $tree path1 path0 >current &&
457      cat >expected <<\EOF &&
458-100644 blob X	path0
459 120000 blob X	path1
460+100644 blob X	path0
461 EOF
462      test_output'
463
464@@ -85,7 +85,6 @@ test_expect_success \
465      cat >expected <<\EOF &&
466 040000 tree X	path2
467 040000 tree X	path2/baz
468-100644 blob X	path2/baz/b
469 120000 blob X	path2/bazbo
470 100644 blob X	path2/foo
471 EOF
472diff a/tree.c b/tree.c
473--- a/tree.c
474+++ b/tree.c
475@@ -133,7 +133,7 @@ int parse_tree_buffer(struct tree *item,
476 		}
477 		if (obj)
478 			add_ref(&item->object, obj);
479-
480+		entry->parent = NULL; /* needs to be filled by the user */
481 		*list_p = entry;
482 		list_p = &entry->next;
483 	}
484diff a/tree.h b/tree.h
485--- a/tree.h
486+++ b/tree.h
487@@ -16,6 +16,7 @@ struct tree_entry_list {
488 		struct tree *tree;
489 		struct blob *blob;
490 	} item;
491+	struct tree_entry_list *parent;
492 };
493
494 struct tree {
495