1 files changed, 260 insertions, 0 deletions
diff --git a/tree-walk.c b/tree-walk.c
new file mode 100644
index 000000000..02e2aed77
--- /dev/null
+++ b/tree-walk.c
@@ -0,0 +1,260 @@
+#include "cache.h"
+#include "tree-walk.h"
+#include "tree.h"
+
+static const char *get_mode(const char *str, unsigned int *modep)
+{
+	unsigned char c;
+	unsigned int mode = 0;
+
+	if (*str == ' ')
+		return NULL;
+
+	while ((c = *str++) != ' ') {
+		if (c < '0' || c > '7')
+			return NULL;
+		mode = (mode << 3) + (c - '0');
+	}
+	*modep = mode;
+	return str;
+}
+
+static void decode_tree_entry(struct tree_desc *desc, const char *buf, unsigned long size)
+{
+	const char *path;
+	unsigned int mode, len;
+
+	if (size < 24 || buf[size - 21])
+		die("corrupt tree file");
+
+	path = get_mode(buf, &mode);
+	if (!path || !*path)
+		die("corrupt tree file");
+	len = strlen(path) + 1;
+
+	/* Initialize the descriptor entry */
+	desc->entry.path = path;
+	desc->entry.mode = mode;
+	desc->entry.sha1 = (const unsigned char *)(path + len);
+}
+
+void init_tree_desc(struct tree_desc *desc, const void *buffer, unsigned long size)
+{
+	desc->buffer = buffer;
+	desc->size = size;
+	if (size)
+		decode_tree_entry(desc, buffer, size);
+}
+
+void *fill_tree_descriptor(struct tree_desc *desc, const unsigned char *sha1)
+{
+	unsigned long size = 0;
+	void *buf = NULL;
+
+	if (sha1) {
+		buf = read_object_with_reference(sha1, tree_type, &size, NULL);
+		if (!buf)
+			die("unable to read tree %s", sha1_to_hex(sha1));
+	}
+	init_tree_desc(desc, buf, size);
+	return buf;
+}
+
+static int entry_compare(struct name_entry *a, struct name_entry *b)
+{
+	return df_name_compare(
+			a->path, tree_entry_len(a->path, a->sha1), a->mode,
+			b->path, tree_entry_len(b->path, b->sha1), b->mode);
+}
+
+static void entry_clear(struct name_entry *a)
+{
+	memset(a, 0, sizeof(*a));
+}
+
+static void entry_extract(struct tree_desc *t, struct name_entry *a)
+{
+	*a = t->entry;
+}
+
+void update_tree_entry(struct tree_desc *desc)
+{
+	const void *buf = desc->buffer;
+	const unsigned char *end = desc->entry.sha1 + 20;
+	unsigned long size = desc->size;
+	unsigned long len = end - (const unsigned char *)buf;
+
+	if (size < len)
+		die("corrupt tree file");
+	buf = end;
+	size -= len;
+	desc->buffer = buf;
+	desc->size = size;
+	if (size)
+		decode_tree_entry(desc, buf, size);
+}
+
+int tree_entry(struct tree_desc *desc, struct name_entry *entry)
+{
+	if (!desc->size)
+		return 0;
+
+	*entry = desc->entry;
+	update_tree_entry(desc);
+	return 1;
+}
+
+void setup_traverse_info(struct traverse_info *info, const char *base)
+{
+	int pathlen = strlen(base);
+	static struct traverse_info dummy;
+
+	memset(info, 0, sizeof(*info));
+	if (pathlen && base[pathlen-1] == '/')
+		pathlen--;
+	info->pathlen = pathlen ? pathlen + 1 : 0;
+	info->name.path = base;
+	info->name.sha1 = (void *)(base + pathlen + 1);
+	if (pathlen)
+		info->prev = &dummy;
+}
+
+char *make_traverse_path(char *path, const struct traverse_info *info, const struct name_entry *n)
+{
+	int len = tree_entry_len(n->path, n->sha1);
+	int pathlen = info->pathlen;
+
+	path[pathlen + len] = 0;
+	for (;;) {
+		memcpy(path + pathlen, n->path, len);
+		if (!pathlen)
+			break;
+		path[--pathlen] = '/';
+		n = &info->name;
+		len = tree_entry_len(n->path, n->sha1);
+		info = info->prev;
+		pathlen -= len;
+	}
+	return path;
+}
+
+int traverse_trees(int n, struct tree_desc *t, struct traverse_info *info)
+{
+	int ret = 0;
+	struct name_entry *entry = xmalloc(n*sizeof(*entry));
+
+	for (;;) {
+		unsigned long mask = 0;
+		unsigned long dirmask = 0;
+		int i, last;
+
+		last = -1;
+		for (i = 0; i < n; i++) {
+			if (!t[i].size)
+				continue;
+			entry_extract(t+i, entry+i);
+			if (last >= 0) {
+				int cmp = entry_compare(entry+i, entry+last);
+
+				/*
+				 * Is the new name bigger than the old one?
+				 * Ignore it
+				 */
+				if (cmp > 0)
+					continue;
+				/*
+				 * Is the new name smaller than the old one?
+				 * Ignore all old ones
+				 */
+				if (cmp < 0)
+					mask = 0;
+			}
+			mask |= 1ul << i;
+			if (S_ISDIR(entry[i].mode))
+				dirmask |= 1ul << i;
+			last = i;
+		}
+		if (!mask)
+			break;
+		dirmask &= mask;
+
+		/*
+		 * Clear all the unused name-entries.
+		 */
+		for (i = 0; i < n; i++) {
+			if (mask & (1ul << i))
+				continue;
+			entry_clear(entry + i);
+		}
+		ret = info->fn(n, mask, dirmask, entry, info);
+		if (ret < 0)
+			break;
+		if (ret)
+			mask &= ret;
+		ret = 0;
+		for (i = 0; i < n; i++) {
+			if (mask & (1ul << i))
+				update_tree_entry(t + i);
+		}
+	}
+	free(entry);
+	return ret;
+}
+
+static int find_tree_entry(struct tree_desc *t, const char *name, unsigned char *result, unsigned *mode)
+{
+	int namelen = strlen(name);
+	while (t->size) {
+		const char *entry;
+		const unsigned char *sha1;
+		int entrylen, cmp;
+
+		sha1 = tree_entry_extract(t, &entry, mode);
+		update_tree_entry(t);
+		entrylen = tree_entry_len(entry, sha1);
+		if (entrylen > namelen)
+			continue;
+		cmp = memcmp(name, entry, entrylen);
+		if (cmp > 0)
+			continue;
+		if (cmp < 0)
+			break;
+		if (entrylen == namelen) {
+			hashcpy(result, sha1);
+			return 0;
+		}
+		if (name[entrylen] != '/')
+			continue;
+		if (!S_ISDIR(*mode))
+			break;
+		if (++entrylen == namelen) {
+			hashcpy(result, sha1);
+			return 0;
+		}
+		return get_tree_entry(sha1, name + entrylen, result, mode);
+	}
+	return -1;
+}
+
+int get_tree_entry(const unsigned char *tree_sha1, const char *name, unsigned char *sha1, unsigned *mode)
+{
+	int retval;
+	void *tree;
+	unsigned long size;
+	struct tree_desc t;
+	unsigned char root[20];
+
+	tree = read_object_with_reference(tree_sha1, tree_type, &size, root);
+	if (!tree)
+		return -1;
+
+	if (name[0] == '\0') {
+		hashcpy(sha1, root);
+		return 0;
+	}
+
+	init_tree_desc(&t, tree, size);
+	retval = find_tree_entry(&t, name, sha1, mode);
+	free(tree);
+	return retval;
+}