Merge branch 'lt/tree-2'

* lt/tree-2:
  fetch.c: do not call process_tree() from process_tree().
  tree_entry(): new tree-walking helper function
  adjust to the rebased series by Linus.
  Remove "tree->entries" tree-entry list from tree parser
  Switch "read_tree_recursive()" over to tree-walk functionality
  Make "tree_entry" have a SHA1 instead of a union of object pointers
  Add raw tree buffer info to "struct tree"
  Remove last vestiges of generic tree_entry_list
  Convert fetch.c: process_tree() to raw tree walker
  Convert "mark_tree_uninteresting()" to raw tree walker
  Remove unused "zeropad" entry from tree_list_entry
  fsck-objects: avoid unnecessary tree_entry_list usage
  Remove "tree->entries" tree-entry list from tree parser
  builtin-read-tree.c: avoid tree_entry_list in prime_cache_tree_rec()
  Switch "read_tree_recursive()" over to tree-walk functionality
  Make "tree_entry" have a SHA1 instead of a union of object pointers
  Make "struct tree" contain the pointer to the tree buffer

16 files changed, 293 insertions, 216 deletions

diff --git a/blame.c b/blame.c
index 99ceea81d..88bfec262 100644
--- a/blame.c
+++ b/blame.c
@@ -149,7 +149,7 @@ static void free_patch(struct patch *p)
 	free(p);
 }
 
-static int get_blob_sha1_internal(unsigned char *sha1, const char *base,
+static int get_blob_sha1_internal(const unsigned char *sha1, const char *base,
 				  int baselen, const char *pathname,
 				  unsigned mode, int stage);
 
@@ -178,7 +178,7 @@ static int get_blob_sha1(struct tree *t, const char *pathname,
 	return 0;
 }
 
-static int get_blob_sha1_internal(unsigned char *sha1, const char *base,
+static int get_blob_sha1_internal(const unsigned char *sha1, const char *base,
 				  int baselen, const char *pathname,
 				  unsigned mode, int stage)
 {
diff --git a/builtin-grep.c b/builtin-grep.c
index 53de8a883..acc4eea36 100644
--- a/builtin-grep.c
+++ b/builtin-grep.c
@@ -578,11 +578,9 @@ static int grep_tree(struct grep_opt *opt, const char **paths,
 		     struct tree_desc *tree,
 		     const char *tree_name, const char *base)
 {
-	unsigned mode;
 	int len;
 	int hit = 0;
-	const char *path;
-	const unsigned char *sha1;
+	struct name_entry entry;
 	char *down;
 	char *path_buf = xmalloc(PATH_MAX + strlen(tree_name) + 100);
 
@@ -597,36 +595,32 @@ static int grep_tree(struct grep_opt *opt, const char **paths,
 	}
 	len = strlen(path_buf);
 
-	while (tree->size) {
-		int pathlen;
-		sha1 = tree_entry_extract(tree, &path, &mode);
-		pathlen = strlen(path);
-		strcpy(path_buf + len, path);
+	while (tree_entry(tree, &entry)) {
+		strcpy(path_buf + len, entry.path);
 
-		if (S_ISDIR(mode))
+		if (S_ISDIR(entry.mode))
 			/* Match "abc/" against pathspec to
 			 * decide if we want to descend into "abc"
 			 * directory.
 			 */
-			strcpy(path_buf + len + pathlen, "/");
+			strcpy(path_buf + len + entry.pathlen, "/");
 
 		if (!pathspec_matches(paths, down))
 			;
-		else if (S_ISREG(mode))
-			hit |= grep_sha1(opt, sha1, path_buf);
-		else if (S_ISDIR(mode)) {
+		else if (S_ISREG(entry.mode))
+			hit |= grep_sha1(opt, entry.sha1, path_buf);
+		else if (S_ISDIR(entry.mode)) {
 			char type[20];
 			struct tree_desc sub;
 			void *data;
-			data = read_sha1_file(sha1, type, &sub.size);
+			data = read_sha1_file(entry.sha1, type, &sub.size);
 			if (!data)
 				die("unable to read tree (%s)",
-				    sha1_to_hex(sha1));
+				    sha1_to_hex(entry.sha1));
 			sub.buf = data;
 			hit |= grep_tree(opt, paths, &sub, tree_name, down);
 			free(data);
 		}
-		update_tree_entry(tree);
 	}
 	return hit;
 }
diff --git a/builtin-ls-tree.c b/builtin-ls-tree.c
index 48385d59f..b8d0d88ba 100644
--- a/builtin-ls-tree.c
+++ b/builtin-ls-tree.c
@@ -53,7 +53,7 @@ static int show_recursive(const char *base, int baselen, const char *pathname)
 	}
 }
 
-static int show_tree(unsigned char *sha1, const char *base, int baselen,
+static int show_tree(const unsigned char *sha1, const char *base, int baselen,
 		     const char *pathname, unsigned mode, int stage)
 {
 	int retval = 0;
diff --git a/builtin-read-tree.c b/builtin-read-tree.c
index 21361dff4..085e11e7c 100644
--- a/builtin-read-tree.c
+++ b/builtin-read-tree.c
@@ -9,6 +9,7 @@
 
 #include "object.h"
 #include "tree.h"
+#include "tree-walk.h"
 #include "cache-tree.h"
 #include <sys/time.h>
 #include <signal.h>
@@ -29,7 +30,17 @@ static int merge_size = 0;
 
 static struct object_list *trees = NULL;
 
-static struct cache_entry df_conflict_entry = { 
+static struct cache_entry df_conflict_entry = {
+};
+
+struct tree_entry_list {
+	struct tree_entry_list *next;
+	unsigned directory : 1;
+	unsigned executable : 1;
+	unsigned symlink : 1;
+	unsigned int mode;
+	const char *name;
+	const unsigned char *sha1;
 };
 
 static struct tree_entry_list df_conflict_list = {
@@ -39,7 +50,35 @@ static struct tree_entry_list df_conflict_list = {
 
 typedef int (*merge_fn_t)(struct cache_entry **src);
 
-static int entcmp(char *name1, int dir1, char *name2, int dir2)
+static struct tree_entry_list *create_tree_entry_list(struct tree *tree)
+{
+	struct tree_desc desc;
+	struct name_entry one;
+	struct tree_entry_list *ret = NULL;
+	struct tree_entry_list **list_p = &ret;
+
+	desc.buf = tree->buffer;
+	desc.size = tree->size;
+
+	while (tree_entry(&desc, &one)) {
+		struct tree_entry_list *entry;
+
+		entry = xmalloc(sizeof(struct tree_entry_list));
+		entry->name = one.path;
+		entry->sha1 = one.sha1;
+		entry->mode = one.mode;
+		entry->directory = S_ISDIR(one.mode) != 0;
+		entry->executable = (one.mode & S_IXUSR) != 0;
+		entry->symlink = S_ISLNK(one.mode) != 0;
+		entry->next = NULL;
+
+		*list_p = entry;
+		list_p = &entry->next;
+	}
+	return ret;
+}
+
+static int entcmp(const char *name1, int dir1, const char *name2, int dir2)
 {
 	int len1 = strlen(name1);
 	int len2 = strlen(name2);
@@ -67,7 +106,7 @@ static int unpack_trees_rec(struct tree_entry_list **posns, int len,
 	int src_size = len + 1;
 	do {
 		int i;
-		char *first;
+		const char *first;
 		int firstdir = 0;
 		int pathlen;
 		unsigned ce_size;
@@ -161,9 +200,10 @@ static int unpack_trees_rec(struct tree_entry_list **posns, int len,
 			}
 
 			if (posns[i]->directory) {
+				struct tree *tree = lookup_tree(posns[i]->sha1);
 				any_dirs = 1;
-				parse_tree(posns[i]->item.tree);
-				subposns[i] = posns[i]->item.tree->entries;
+				parse_tree(tree);
+				subposns[i] = create_tree_entry_list(tree);
 				posns[i] = posns[i]->next;
 				src[i + merge] = &df_conflict_entry;
 				continue;
@@ -187,7 +227,7 @@ static int unpack_trees_rec(struct tree_entry_list **posns, int len,
 
 			any_files = 1;
 
-			memcpy(ce->sha1, posns[i]->item.any->sha1, 20);
+			memcpy(ce->sha1, posns[i]->sha1, 20);
 			src[i + merge] = ce;
 			subposns[i] = &df_conflict_list;
 			posns[i] = posns[i]->next;
@@ -368,7 +408,7 @@ static int unpack_trees(merge_fn_t fn)
 	if (len) {
 		posns = xmalloc(len * sizeof(struct tree_entry_list *));
 		for (i = 0; i < len; i++) {
-			posns[i] = ((struct tree *) posn->item)->entries;
+			posns[i] = create_tree_entry_list((struct tree *) posn->item);
 			posn = posn->next;
 		}
 		if (unpack_trees_rec(posns, len, "", fn, &indpos))
@@ -775,19 +815,23 @@ static int read_cache_unmerged(void)
 
 static void prime_cache_tree_rec(struct cache_tree *it, struct tree *tree)
 {
-	struct tree_entry_list *ent;
+	struct tree_desc desc;
+	struct name_entry entry;
 	int cnt;
 
 	memcpy(it->sha1, tree->object.sha1, 20);
-	for (cnt = 0, ent = tree->entries; ent; ent = ent->next) {
-		if (!ent->directory)
+	desc.buf = tree->buffer;
+	desc.size = tree->size;
+	cnt = 0;
+	while (tree_entry(&desc, &entry)) {
+		if (!S_ISDIR(entry.mode))
 			cnt++;
 		else {
 			struct cache_tree_sub *sub;
-			struct tree *subtree = (struct tree *)ent->item.tree;
+			struct tree *subtree = lookup_tree(entry.sha1);
 			if (!subtree->object.parsed)
 				parse_tree(subtree);
-			sub = cache_tree_sub(it, ent->name);
+			sub = cache_tree_sub(it, entry.path);
 			sub->cache_tree = cache_tree();
 			prime_cache_tree_rec(sub->cache_tree, subtree);
 			cnt += sub->cache_tree->entry_count;
diff --git a/builtin-rev-list.c b/builtin-rev-list.c
index 5277d3cf1..17c04b962 100644
--- a/builtin-rev-list.c
+++ b/builtin-rev-list.c
@@ -113,7 +113,8 @@ static struct object_list **process_tree(struct tree *tree,
 					 const char *name)
 {
 	struct object *obj = &tree->object;
-	struct tree_entry_list *entry;
+	struct tree_desc desc;
+	struct name_entry entry;
 	struct name_path me;
 
 	if (!revs.tree_objects)
@@ -128,18 +129,18 @@ static struct object_list **process_tree(struct tree *tree,
 	me.up = path;
 	me.elem = name;
 	me.elem_len = strlen(name);
-	entry = tree->entries;
-	tree->entries = NULL;
-	while (entry) {
-		struct tree_entry_list *next = entry->next;
-		if (entry->directory)
-			p = process_tree(entry->item.tree, p, &me, entry->name);
+
+	desc.buf = tree->buffer;
+	desc.size = tree->size;
+
+	while (tree_entry(&desc, &entry)) {
+		if (S_ISDIR(entry.mode))
+			p = process_tree(lookup_tree(entry.sha1), p, &me, name);
 		else
-			p = process_blob(entry->item.blob, p, &me, entry->name);
-		free(entry->name);
-		free(entry);
-		entry = next;
+			p = process_blob(lookup_blob(entry.sha1), p, &me, name);
 	}
+	free(tree->buffer);
+	tree->buffer = NULL;
 	return p;
 }
 
diff --git a/builtin-tar-tree.c b/builtin-tar-tree.c
index 2d5e06fb6..5f740cf70 100644
--- a/builtin-tar-tree.c
+++ b/builtin-tar-tree.c
@@ -271,30 +271,25 @@ static void write_global_extended_header(const unsigned char *sha1)
 static void traverse_tree(struct tree_desc *tree, struct strbuf *path)
 {
 	int pathlen = path->len;
+	struct name_entry entry;
 
-	while (tree->size) {
-		const char *name;
-		const unsigned char *sha1;
-		unsigned mode;
+	while (tree_entry(tree, &entry)) {
 		void *eltbuf;
 		char elttype[20];
 		unsigned long eltsize;
 
-		sha1 = tree_entry_extract(tree, &name, &mode);
-		update_tree_entry(tree);
-
-		eltbuf = read_sha1_file(sha1, elttype, &eltsize);
+		eltbuf = read_sha1_file(entry.sha1, elttype, &eltsize);
 		if (!eltbuf)
-			die("cannot read %s", sha1_to_hex(sha1));
+			die("cannot read %s", sha1_to_hex(entry.sha1));
 
 		path->len = pathlen;
-		strbuf_append_string(path, name);
-		if (S_ISDIR(mode))
+		strbuf_append_string(path, entry.path);
+		if (S_ISDIR(entry.mode))
 			strbuf_append_string(path, "/");
 
-		write_entry(sha1, path, mode, eltbuf, eltsize);
+		write_entry(entry.sha1, path, entry.mode, eltbuf, eltsize);
 
-		if (S_ISDIR(mode)) {
+		if (S_ISDIR(entry.mode)) {
 			struct tree_desc subtree;
 			subtree.buf = eltbuf;
 			subtree.size = eltsize;
diff --git a/fetch.c b/fetch.c
index cc6013e7a..e040ef97b 100644
--- a/fetch.c
+++ b/fetch.c
@@ -3,6 +3,7 @@
 #include "cache.h"
 #include "commit.h"
 #include "tree.h"
+#include "tree-walk.h"
 #include "tag.h"
 #include "blob.h"
 #include "refs.h"
@@ -37,21 +38,33 @@ static int process(struct object *obj);
 
 static int process_tree(struct tree *tree)
 {
-	struct tree_entry_list *entry;
+	struct tree_desc desc;
+	struct name_entry entry;
 
 	if (parse_tree(tree))
 		return -1;
 
-	entry = tree->entries;
-	tree->entries = NULL;
-	while (entry) {
-		struct tree_entry_list *next = entry->next;
-		if (process(entry->item.any))
+	desc.buf = tree->buffer;
+	desc.size = tree->size;
+	while (tree_entry(&desc, &entry)) {
+		struct object *obj = NULL;
+
+		if (S_ISDIR(entry.mode)) {
+			struct tree *tree = lookup_tree(entry.sha1);
+			if (tree)
+				obj = &tree->object;
+		}
+		else {
+			struct blob *blob = lookup_blob(entry.sha1);
+			if (blob)
+				obj = &blob->object;
+		}
+		if (!obj || process(obj))
 			return -1;
-		free(entry->name);
-		free(entry);
-		entry = next;
 	}
+	free(tree->buffer);
+	tree->buffer = NULL;
+	tree->size = 0;
 	return 0;
 }
 
diff --git a/fsck-objects.c b/fsck-objects.c
index 1922b6d84..33ce366e9 100644
--- a/fsck-objects.c
+++ b/fsck-objects.c
@@ -9,8 +9,10 @@
 #include "refs.h"
 #include "pack.h"
 #include "cache-tree.h"
+#include "tree-walk.h"
 
 #define REACHABLE 0x0001
+#define SEEN      0x0002
 
 static int show_root = 0;
 static int show_tags = 0;
@@ -115,15 +117,15 @@ static void check_connectivity(void)
 #define TREE_UNORDERED (-1)
 #define TREE_HAS_DUPS  (-2)
 
-static int verify_ordered(struct tree_entry_list *a, struct tree_entry_list *b)
+static int verify_ordered(unsigned mode1, const char *name1, unsigned mode2, const char *name2)
 {
-	int len1 = strlen(a->name);
-	int len2 = strlen(b->name);
+	int len1 = strlen(name1);
+	int len2 = strlen(name2);
 	int len = len1 < len2 ? len1 : len2;
 	unsigned char c1, c2;
 	int cmp;
 
-	cmp = memcmp(a->name, b->name, len);
+	cmp = memcmp(name1, name2, len);
 	if (cmp < 0)
 		return 0;
 	if (cmp > 0)
@@ -134,8 +136,8 @@ static int verify_ordered(struct tree_entry_list *a, struct tree_entry_list *b)
 	 * Now we need to order the next one, but turn
 	 * a '\0' into a '/' for a directory entry.
 	 */
-	c1 = a->name[len];
-	c2 = b->name[len];
+	c1 = name1[len];
+	c2 = name2[len];
 	if (!c1 && !c2)
 		/*
 		 * git-write-tree used to write out a nonsense tree that has
@@ -143,9 +145,9 @@ static int verify_ordered(struct tree_entry_list *a, struct tree_entry_list *b)
 		 * sure we do not have duplicate entries.
 		 */
 		return TREE_HAS_DUPS;
-	if (!c1 && a->directory)
+	if (!c1 && S_ISDIR(mode1))
 		c1 = '/';
-	if (!c2 && b->directory)
+	if (!c2 && S_ISDIR(mode2))
 		c2 = '/';
 	return c1 < c2 ? 0 : TREE_UNORDERED;
 }
@@ -158,17 +160,32 @@ static int fsck_tree(struct tree *item)
 	int has_bad_modes = 0;
 	int has_dup_entries = 0;
 	int not_properly_sorted = 0;
-	struct tree_entry_list *entry, *last;
+	struct tree_desc desc;
+	unsigned o_mode;
+	const char *o_name;
+	const unsigned char *o_sha1;
 
-	last = NULL;
-	for (entry = item->entries; entry; entry = entry->next) {
-		if (strchr(entry->name, '/'))
+	desc.buf = item->buffer;
+	desc.size = item->size;
+
+	o_mode = 0;
+	o_name = NULL;
+	o_sha1 = NULL;
+	while (desc.size) {
+		unsigned mode;
+		const char *name;
+		const unsigned char *sha1;
+
+		sha1 = tree_entry_extract(&desc, &name, &mode);
+
+		if (strchr(name, '/'))
 			has_full_path = 1;
-		has_zero_pad |= entry->zeropad;
+		has_zero_pad |= *(char *)desc.buf == '0';
+		update_tree_entry(&desc);
 
-		switch (entry->mode) {
+		switch (mode) {
 		/*
-		 * Standard modes.. 
+		 * Standard modes..
 		 */
 		case S_IFREG | 0755:
 		case S_IFREG | 0644:
@@ -187,8 +204,8 @@ static int fsck_tree(struct tree *item)
 			has_bad_modes = 1;
 		}
 
-		if (last) {
-			switch (verify_ordered(last, entry)) {
+		if (o_name) {
+			switch (verify_ordered(o_mode, o_name, mode, name)) {
 			case TREE_UNORDERED:
 				not_properly_sorted = 1;
 				break;
@@ -198,17 +215,14 @@ static int fsck_tree(struct tree *item)
 			default:
 				break;
 			}
-			free(last->name);
-			free(last);
 		}
 
-		last = entry;
+		o_mode = mode;
+		o_name = name;
+		o_sha1 = sha1;
 	}
-	if (last) {
-		free(last->name);
-		free(last);
-	}
-	item->entries = NULL;
+	free(item->buffer);
+	item->buffer = NULL;
 
 	retval = 0;
 	if (has_full_path) {
@@ -278,6 +292,9 @@ static int fsck_sha1(unsigned char *sha1)
 	struct object *obj = parse_object(sha1);
 	if (!obj)
 		return error("%s: object not found", sha1_to_hex(sha1));
+	if (obj->flags & SEEN)
+		return 0;
+	obj->flags |= SEEN;
 	if (obj->type == blob_type)
 		return 0;
 	if (obj->type == tree_type)
@@ -465,6 +482,7 @@ int main(int argc, char **argv)
 {
 	int i, heads;
 
+	track_object_refs = 1;
 	setup_git_directory();
 
 	for (i = 1; i < argc; i++) {
diff --git a/http-push.c b/http-push.c
index b4327d924..b1c018a08 100644
--- a/http-push.c
+++ b/http-push.c
@@ -1704,6 +1704,7 @@ static struct object_list **process_blob(struct blob *blob,
 		return p;
 
 	obj->flags |= SEEN;
+	name = strdup(name);
 	return add_object(obj, p, path, name);
 }
 
@@ -1713,7 +1714,8 @@ static struct object_list **process_tree(struct tree *tree,
 					 const char *name)
 {
 	struct object *obj = &tree->object;
-	struct tree_entry_list *entry;
+	struct tree_desc desc;
+	struct name_entry entry;
 	struct name_path me;
 
 	obj->flags |= LOCAL;
@@ -1724,21 +1726,23 @@ static struct object_list **process_tree(struct tree *tree,
 		die("bad tree object %s", sha1_to_hex(obj->sha1));
 
 	obj->flags |= SEEN;
+	name = strdup(name);
 	p = add_object(obj, p, NULL, name);
 	me.up = path;
 	me.elem = name;
 	me.elem_len = strlen(name);
-	entry = tree->entries;
-	tree->entries = NULL;
-	while (entry) {
-		struct tree_entry_list *next = entry->next;
-		if (entry->directory)
-			p = process_tree(entry->item.tree, p, &me, entry->name);
+
+	desc.buf = tree->buffer;
+	desc.size = tree->size;
+
+	while (tree_entry(&desc, &entry)) {
+		if (S_ISDIR(entry.mode))
+			p = process_tree(lookup_tree(entry.sha1), p, &me, name);
 		else
-			p = process_blob(entry->item.blob, p, &me, entry->name);
-		free(entry);
-		entry = next;
+			p = process_blob(lookup_blob(entry.sha1), p, &me, name);
 	}
+	free(tree->buffer);
+	tree->buffer = NULL;
 	return p;
 }
 
diff --git a/object.c b/object.c
index 4d46e0d5e..9adc87479 100644
--- a/object.c
+++ b/object.c
@@ -9,7 +9,7 @@ struct object **objs;
 static int nr_objs;
 int obj_allocs;
 
-int track_object_refs = 1;
+int track_object_refs = 0;
 
 static int hashtable_index(const unsigned char *sha1)
 {
@@ -200,8 +200,11 @@ struct object *parse_object(const unsigned char *sha1)
 			obj = &blob->object;
 		} else if (!strcmp(type, tree_type)) {
 			struct tree *tree = lookup_tree(sha1);
-			parse_tree_buffer(tree, buffer, size);
 			obj = &tree->object;
+			if (!tree->object.parsed) {
+				parse_tree_buffer(tree, buffer, size);
+				buffer = NULL;
+			}
 		} else if (!strcmp(type, commit_type)) {
 			struct commit *commit = lookup_commit(sha1);
 			parse_commit_buffer(commit, buffer, size);
diff --git a/pack-objects.c b/pack-objects.c
index 77284cfdb..3590cd5e5 100644
--- a/pack-objects.c
+++ b/pack-objects.c
@@ -690,25 +690,20 @@ static void add_pbase_object(struct tree_desc *tree,
 			     const char *name,
 			     int cmplen)
 {
-	while (tree->size) {
-		const unsigned char *sha1;
-		const char *entry_name;
-		int entry_len;
-		unsigned mode;
+	struct name_entry entry;
+
+	while (tree_entry(tree,&entry)) {
 		unsigned long size;
 		char type[20];
 
-		sha1 = tree_entry_extract(tree, &entry_name, &mode);
-		update_tree_entry(tree);
-		entry_len = strlen(entry_name);
-		if (entry_len != cmplen ||
-		    memcmp(entry_name, name, cmplen) ||
-		    !has_sha1_file(sha1) ||
-		    sha1_object_info(sha1, type, &size))
+		if (entry.pathlen != cmplen ||
+		    memcmp(entry.path, name, cmplen) ||
+		    !has_sha1_file(entry.sha1) ||
+		    sha1_object_info(entry.sha1, type, &size))
 			continue;
 		if (name[cmplen] != '/') {
 			unsigned hash = name_hash(up, name);
-			add_object_entry(sha1, hash, 1);
+			add_object_entry(entry.sha1, hash, 1);
 			return;
 		}
 		if (!strcmp(type, tree_type)) {
@@ -718,15 +713,15 @@ static void add_pbase_object(struct tree_desc *tree,
 			const char *down = name+cmplen+1;
 			int downlen = name_cmp_len(down);
 
-			tree = pbase_tree_get(sha1);
+			tree = pbase_tree_get(entry.sha1);
 			if (!tree)
 				return;
 			sub.buf = tree->tree_data;
 			sub.size = tree->tree_size;
 
 			me.up = up;
-			me.elem = entry_name;
-			me.len = entry_len;
+			me.elem = entry.path;
+			me.len = entry.pathlen;
 			add_pbase_object(&sub, &me, down, downlen);
 			pbase_tree_put(tree);
 		}
diff --git a/revision.c b/revision.c
index 42c077a4c..6a6952cd5 100644
--- a/revision.c
+++ b/revision.c
@@ -53,8 +53,9 @@ static void mark_blob_uninteresting(struct blob *blob)
 
 void mark_tree_uninteresting(struct tree *tree)
 {
+	struct tree_desc desc;
+	struct name_entry entry;
 	struct object *obj = &tree->object;
-	struct tree_entry_list *entry;
 
 	if (obj->flags & UNINTERESTING)
 		return;
@@ -63,17 +64,22 @@ void mark_tree_uninteresting(struct tree *tree)
 		return;
 	if (parse_tree(tree) < 0)
 		die("bad tree %s", sha1_to_hex(obj->sha1));
-	entry = tree->entries;
-	tree->entries = NULL;
-	while (entry) {
-		struct tree_entry_list *next = entry->next;
-		if (entry->directory)
-			mark_tree_uninteresting(entry->item.tree);
+
+	desc.buf = tree->buffer;
+	desc.size = tree->size;
+	while (tree_entry(&desc, &entry)) {
+		if (S_ISDIR(entry.mode))
+			mark_tree_uninteresting(lookup_tree(entry.sha1));
 		else
-			mark_blob_uninteresting(entry->item.blob);
-		free(entry);
-		entry = next;
+			mark_blob_uninteresting(lookup_blob(entry.sha1));
 	}
+
+	/*
+	 * We don't care about the tree any more
+	 * after it has been marked uninteresting.
+	 */
+	free(tree->buffer);
+	tree->buffer = NULL;
 }
 
 void mark_parents_uninteresting(struct commit *commit)
diff --git a/tree-walk.c b/tree-walk.c
index 392205827..297c6972b 100644
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -37,7 +37,7 @@ static void entry_extract(struct tree_desc *t, struct name_entry *a)
 
 void update_tree_entry(struct tree_desc *desc)
 {
-	void *buf = desc->buf;
+	const void *buf = desc->buf;
 	unsigned long size = desc->size;
 	int len = strlen(buf) + 1 + 20;
 
@@ -63,7 +63,7 @@ static const char *get_mode(const char *str, unsigned int *modep)
 
 const unsigned char *tree_entry_extract(struct tree_desc *desc, const char **pathp, unsigned int *modep)
 {
-	void *tree = desc->buf;
+	const void *tree = desc->buf;
 	unsigned long size = desc->size;
 	int len = strlen(tree)+1;
 	const unsigned char *sha1 = tree + len;
@@ -78,6 +78,35 @@ const unsigned char *tree_entry_extract(struct tree_desc *desc, const char **pat
 	return sha1;
 }
 
+int tree_entry(struct tree_desc *desc, struct name_entry *entry)
+{
+	const void *tree = desc->buf, *path;
+	unsigned long len, size = desc->size;
+
+	if (!size)
+		return 0;
+
+	path = get_mode(tree, &entry->mode);
+	if (!path)
+		die("corrupt tree file");
+
+	entry->path = path;
+	len = strlen(path);
+	entry->pathlen = len;
+
+	path += len + 1;
+	entry->sha1 = path;
+
+	path += 20;
+	len = path - tree;
+	if (len > size)
+		die("corrupt tree file");
+
+	desc->buf = path;
+	desc->size = size - len;
+	return 1;
+}
+
 void traverse_trees(int n, struct tree_desc *t, const char *base, traverse_callback_t callback)
 {
 	struct name_entry *entry = xmalloc(n*sizeof(*entry));
diff --git a/tree-walk.h b/tree-walk.h
index 47438fe1c..e57befa4d 100644
--- a/tree-walk.h
+++ b/tree-walk.h
@@ -2,7 +2,7 @@
 #define TREE_WALK_H
 
 struct tree_desc {
-	void *buf;
+	const void *buf;
 	unsigned long size;
 };
 
@@ -16,6 +16,9 @@ struct name_entry {
 void update_tree_entry(struct tree_desc *);
 const unsigned char *tree_entry_extract(struct tree_desc *, const char **, unsigned int *);
 
+/* Helper function that does both of the above and returns true for success */
+int tree_entry(struct tree_desc *, struct name_entry *);
+
 void *fill_tree_descriptor(struct tree_desc *desc, const unsigned char *sha1);
 
 typedef void (*traverse_callback_t)(int n, unsigned long mask, struct name_entry *entry, const char *base);
diff --git a/tree.c b/tree.c
index d599fb5e1..9bbe2da37 100644
--- a/tree.c
+++ b/tree.c
@@ -3,11 +3,12 @@
 #include "blob.h"
 #include "commit.h"
 #include "tag.h"
+#include "tree-walk.h"
 #include <stdlib.h>
 
 const char *tree_type = "tree";
 
-static int read_one_entry(unsigned char *sha1, const char *base, int baselen, const char *pathname, unsigned mode, int stage)
+static int read_one_entry(const unsigned char *sha1, const char *base, int baselen, const char *pathname, unsigned mode, int stage)
 {
 	int len;
 	unsigned int size;
@@ -77,19 +78,20 @@ int read_tree_recursive(struct tree *tree,
 			int stage, const char **match,
 			read_tree_fn_t fn)
 {
-	struct tree_entry_list *list;
+	struct tree_desc desc;
+	struct name_entry entry;
+
 	if (parse_tree(tree))
 		return -1;
-	list = tree->entries;
-	while (list) {
-		struct tree_entry_list *current = list;
-		list = list->next;
-		if (!match_tree_entry(base, baselen, current->name,
-				      current->mode, match))
+
+	desc.buf = tree->buffer;
+	desc.size = tree->size;
+
+	while (tree_entry(&desc, &entry)) {
+		if (!match_tree_entry(base, baselen, entry.path, entry.mode, match))
 			continue;
 
-		switch (fn(current->item.any->sha1, base, baselen,
-			   current->name, current->mode, stage)) {
+		switch (fn(entry.sha1, base, baselen, entry.path, entry.mode, stage)) {
 		case 0:
 			continue;
 		case READ_TREE_RECURSIVE:
@@ -97,18 +99,17 @@ int read_tree_recursive(struct tree *tree,
 		default:
 			return -1;
 		}
-		if (current->directory) {
+		if (S_ISDIR(entry.mode)) {
 			int retval;
-			int pathlen = strlen(current->name);
 			char *newbase;
 
-			newbase = xmalloc(baselen + 1 + pathlen);
+			newbase = xmalloc(baselen + 1 + entry.pathlen);
 			memcpy(newbase, base, baselen);
-			memcpy(newbase + baselen, current->name, pathlen);
-			newbase[baselen + pathlen] = '/';
-			retval = read_tree_recursive(current->item.tree,
+			memcpy(newbase + baselen, entry.path, entry.pathlen);
+			newbase[baselen + entry.pathlen] = '/';
+			retval = read_tree_recursive(lookup_tree(entry.sha1),
 						     newbase,
-						     baselen + pathlen + 1,
+						     baselen + entry.pathlen + 1,
 						     stage, match, fn);
 			free(newbase);
 			if (retval)
@@ -143,61 +144,49 @@ struct tree *lookup_tree(const unsigned char *sha1)
 	return (struct tree *) obj;
 }
 
-int parse_tree_buffer(struct tree *item, void *buffer, unsigned long size)
+static int track_tree_refs(struct tree *item)
 {
-	void *bufptr = buffer;
-	struct tree_entry_list **list_p;
-	int n_refs = 0;
+	int n_refs = 0, i;
+	struct object_refs *refs;
+	struct tree_desc desc;
+	struct name_entry entry;
+
+	/* Count how many entries there are.. */
+	desc.buf = item->buffer;
+	desc.size = item->size;
+	while (desc.size) {
+		n_refs++;
+		update_tree_entry(&desc);
+	}
 
-	if (item->object.parsed)
-		return 0;
-	item->object.parsed = 1;
-	list_p = &item->entries;
-	while (size) {
+	/* Allocate object refs and walk it again.. */
+	i = 0;
+	refs = alloc_object_refs(n_refs);
+	desc.buf = item->buffer;
+	desc.size = item->size;
+	while (tree_entry(&desc, &entry)) {
 		struct object *obj;
-		struct tree_entry_list *entry;
-		int len = 1+strlen(bufptr);
-		unsigned char *file_sha1 = bufptr + len;
-		char *path = strchr(bufptr, ' ');
-		unsigned int mode;
-		if (size < len + 20 || !path || 
-		    sscanf(bufptr, "%o", &mode) != 1)
-			return -1;
 
-		entry = xmalloc(sizeof(struct tree_entry_list));
-		entry->name = strdup(path + 1);
-		entry->directory = S_ISDIR(mode) != 0;
-		entry->executable = (mode & S_IXUSR) != 0;
-		entry->symlink = S_ISLNK(mode) != 0;
-		entry->zeropad = *(char *)bufptr == '0';
-		entry->mode = mode;
-		entry->next = NULL;
-
-		bufptr += len + 20;
-		size -= len + 20;
-
-		if (entry->directory) {
-			entry->item.tree = lookup_tree(file_sha1);
-			obj = &entry->item.tree->object;
-		} else {
-			entry->item.blob = lookup_blob(file_sha1);
-			obj = &entry->item.blob->object;
-		}
-		if (obj)
-			n_refs++;
-		*list_p = entry;
-		list_p = &entry->next;
+		if (S_ISDIR(entry.mode))
+			obj = &lookup_tree(entry.sha1)->object;
+		else
+			obj = &lookup_blob(entry.sha1)->object;
+		refs->ref[i++] = obj;
 	}
+	set_object_refs(&item->object, refs);
+	return 0;
+}
 
-	if (track_object_refs) {
-		struct tree_entry_list *entry;
-		unsigned i = 0;
-		struct object_refs *refs = alloc_object_refs(n_refs);
-		for (entry = item->entries; entry; entry = entry->next)
-			refs->ref[i++] = entry->item.any;
-		set_object_refs(&item->object, refs);
-	}
+int parse_tree_buffer(struct tree *item, void *buffer, unsigned long size)
+{
+	if (item->object.parsed)
+		return 0;
+	item->object.parsed = 1;
+	item->buffer = buffer;
+	item->size = size;
 
+	if (track_object_refs)
+		track_tree_refs(item);
 	return 0;
 }
 
@@ -206,7 +195,6 @@ int parse_tree(struct tree *item)
 	 char type[20];
 	 void *buffer;
 	 unsigned long size;
-	 int ret;
 
 	if (item->object.parsed)
 		return 0;
@@ -219,9 +207,7 @@ int parse_tree(struct tree *item)
 		return error("Object %s not a tree",
 			     sha1_to_hex(item->object.sha1));
 	}
-	ret = parse_tree_buffer(item, buffer, size);
-	free(buffer);
-	return ret;
+	return parse_tree_buffer(item, buffer, size);
 }
 
 struct tree *parse_tree_indirect(const unsigned char *sha1)
diff --git a/tree.h b/tree.h
index 330ab64bb..dd25c539e 100644
--- a/tree.h
+++ b/tree.h
@@ -5,24 +5,10 @@
 
 extern const char *tree_type;
 
-struct tree_entry_list {
-	struct tree_entry_list *next;
-	unsigned directory : 1;
-	unsigned executable : 1;
-	unsigned symlink : 1;
-	unsigned zeropad : 1;
-	unsigned int mode;
-	char *name;
-	union {
-		struct object *any;
-		struct tree *tree;
-		struct blob *blob;
-	} item;
-};
-
 struct tree {
 	struct object object;
-	struct tree_entry_list *entries;
+	void *buffer;
+	unsigned long size;
 };
 
 struct tree *lookup_tree(const unsigned char *sha1);
@@ -35,7 +21,7 @@ int parse_tree(struct tree *tree);
 struct tree *parse_tree_indirect(const unsigned char *sha1);
 
 #define READ_TREE_RECURSIVE 1
-typedef int (*read_tree_fn_t)(unsigned char *, const char *, int, const char *, unsigned int, int);
+typedef int (*read_tree_fn_t)(const unsigned char *, const char *, int, const char *, unsigned int, int);
 
 extern int read_tree_recursive(struct tree *tree,
 			       const char *base, int baselen,