1 files changed, 184 insertions, 0 deletions
diff --git a/src/tree-cache.c b/src/tree-cache.c
new file mode 100644
index 000000000..ebc2c6807
--- /dev/null
+++ b/src/tree-cache.c
@@ -0,0 +1,184 @@
+/*
+ * Copyright (C) 2009-2012 the libgit2 contributors
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+
+#include "tree-cache.h"
+
+static git_tree_cache *find_child(const git_tree_cache *tree, const char *path)
+{
+	size_t i, dirlen;
+	const char *end;
+
+	end = strchr(path, '/');
+	if (end == NULL) {
+		end = strrchr(path, '\0');
+	}
+
+	dirlen = end - path;
+
+	for (i = 0; i < tree->children_count; ++i) {
+		const char *childname = tree->children[i]->name;
+
+		if (strlen(childname) == dirlen && !memcmp(path, childname, dirlen))
+			return tree->children[i];
+	}
+
+	return NULL;
+}
+
+void git_tree_cache_invalidate_path(git_tree_cache *tree, const char *path)
+{
+	const char *ptr = path, *end;
+
+	if (tree == NULL)
+		return;
+
+	tree->entries = -1;
+
+	while (ptr != NULL) {
+		end = strchr(ptr, '/');
+
+		if (end == NULL) /* End of path */
+			break;
+
+		tree = find_child(tree, ptr);
+		if (tree == NULL) /* We don't have that tree */
+			return;
+
+		tree->entries = -1;
+		ptr = end + 1;
+	}
+}
+
+const git_tree_cache *git_tree_cache_get(const git_tree_cache *tree, const char *path)
+{
+	const char *ptr = path, *end;
+
+	if (tree == NULL) {
+		return NULL;
+	}
+
+	while (1) {
+		end = strchr(ptr, '/');
+
+		tree = find_child(tree, ptr);
+		if (tree == NULL) { /* Can't find it */
+			return NULL;
+		}
+
+		if (end == NULL || end + 1 == '\0')
+			return tree;
+
+		ptr = end + 1;
+	}
+}
+
+static int read_tree_internal(git_tree_cache **out,
+		const char **buffer_in, const char *buffer_end, git_tree_cache *parent)
+{
+	git_tree_cache *tree = NULL;
+	const char *name_start, *buffer;
+	int count;
+	size_t name_len;
+
+	buffer = name_start = *buffer_in;
+
+	if ((buffer = memchr(buffer, '\0', buffer_end - buffer)) == NULL)
+		goto corrupted;
+
+	if (++buffer >= buffer_end)
+		goto corrupted;
+
+	name_len = strlen(name_start);
+	tree = git__malloc(sizeof(git_tree_cache) + name_len + 1);
+	GITERR_CHECK_ALLOC(tree);
+
+	memset(tree, 0x0, sizeof(git_tree_cache));
+	tree->parent = parent;
+
+	/* NUL-terminated tree name */
+	memcpy(tree->name, name_start, name_len);
+	tree->name[name_len] = '\0';
+
+	/* Blank-terminated ASCII decimal number of entries in this tree */
+	if (git__strtol32(&count, buffer, &buffer, 10) < 0 || count < -1)
+		goto corrupted;
+
+	tree->entries = count;
+
+	if (*buffer != ' ' || ++buffer >= buffer_end)
+		goto corrupted;
+
+	 /* Number of children of the tree, newline-terminated */
+	if (git__strtol32(&count, buffer, &buffer, 10) < 0 || count < 0)
+		goto corrupted;
+
+	tree->children_count = count;
+
+	if (*buffer != '\n' || ++buffer > buffer_end)
+		goto corrupted;
+
+	/* The SHA1 is only there if it's not invalidated */
+	if (tree->entries >= 0) {
+		/* 160-bit SHA-1 for this tree and it's children */
+		if (buffer + GIT_OID_RAWSZ > buffer_end)
+			goto corrupted;
+
+		git_oid_fromraw(&tree->oid, (const unsigned char *)buffer);
+		buffer += GIT_OID_RAWSZ;
+	}
+
+	/* Parse children: */
+	if (tree->children_count > 0) {
+		unsigned int i;
+
+		tree->children = git__malloc(tree->children_count * sizeof(git_tree_cache *));
+		GITERR_CHECK_ALLOC(tree->children);
+
+		for (i = 0; i < tree->children_count; ++i) {
+			if (read_tree_internal(&tree->children[i], &buffer, buffer_end, tree) < 0)
+				return -1;
+		}
+	}
+
+	*buffer_in = buffer;
+	*out = tree;
+	return 0;
+
+ corrupted:
+	git_tree_cache_free(tree);
+	giterr_set(GITERR_INDEX, "Corruped TREE extension in index");
+	return -1;
+}
+
+int git_tree_cache_read(git_tree_cache **tree, const char *buffer, size_t buffer_size)
+{
+	const char *buffer_end = buffer + buffer_size;
+
+	if (read_tree_internal(tree, &buffer, buffer_end, NULL) < 0)
+		return -1;
+
+	if (buffer < buffer_end) {
+		giterr_set(GITERR_INDEX, "Corruped TREE extension in index (unexpected trailing data)");
+		return -1;
+	}
+
+	return 0;
+}
+
+void git_tree_cache_free(git_tree_cache *tree)
+{
+	unsigned int i;
+
+	if (tree == NULL)
+		return;
+
+	for (i = 0; i < tree->children_count; ++i)
+		git_tree_cache_free(tree->children[i]);
+
+	git__free(tree->children);
+	git__free(tree);
+}