builtin-fsck: move common object checking code to fsck.c

Signed-off-by: Martin Koegler <mkoegler@auto.tuwien.ac.at>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 215 insertions, 0 deletions

diff --git a/fsck.c b/fsck.c
index 98fb41af68..0680862151 100644
--- a/fsck.c
+++ b/fsck.c
@@ -89,3 +89,218 @@ int fsck_walk(struct object *obj, fsck_walk_func walk, void *data)
 		return -1;
 	}
 }
+
+/*
+ * The entries in a tree are ordered in the _path_ order,
+ * which means that a directory entry is ordered by adding
+ * a slash to the end of it.
+ *
+ * So a directory called "a" is ordered _after_ a file
+ * called "a.c", because "a/" sorts after "a.c".
+ */
+#define TREE_UNORDERED (-1)
+#define TREE_HAS_DUPS  (-2)
+
+static int verify_ordered(unsigned mode1, const char *name1, unsigned mode2, const char *name2)
+{
+	int len1 = strlen(name1);
+	int len2 = strlen(name2);
+	int len = len1 < len2 ? len1 : len2;
+	unsigned char c1, c2;
+	int cmp;
+
+	cmp = memcmp(name1, name2, len);
+	if (cmp < 0)
+		return 0;
+	if (cmp > 0)
+		return TREE_UNORDERED;
+
+	/*
+	 * Ok, the first <len> characters are the same.
+	 * Now we need to order the next one, but turn
+	 * a '\0' into a '/' for a directory entry.
+	 */
+	c1 = name1[len];
+	c2 = name2[len];
+	if (!c1 && !c2)
+		/*
+		 * git-write-tree used to write out a nonsense tree that has
+		 * entries with the same name, one blob and one tree.  Make
+		 * sure we do not have duplicate entries.
+		 */
+		return TREE_HAS_DUPS;
+	if (!c1 && S_ISDIR(mode1))
+		c1 = '/';
+	if (!c2 && S_ISDIR(mode2))
+		c2 = '/';
+	return c1 < c2 ? 0 : TREE_UNORDERED;
+}
+
+static int fsck_tree(struct tree *item, int strict, fsck_error error_func)
+{
+	int retval;
+	int has_full_path = 0;
+	int has_empty_name = 0;
+	int has_zero_pad = 0;
+	int has_bad_modes = 0;
+	int has_dup_entries = 0;
+	int not_properly_sorted = 0;
+	struct tree_desc desc;
+	unsigned o_mode;
+	const char *o_name;
+	const unsigned char *o_sha1;
+
+	init_tree_desc(&desc, item->buffer, item->size);
+
+	o_mode = 0;
+	o_name = NULL;
+	o_sha1 = NULL;
+	if (!desc.size)
+		return error_func(&item->object, FSCK_ERROR, "empty tree");
+
+	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;
+		if (!*name)
+			has_empty_name = 1;
+		has_zero_pad |= *(char *)desc.buffer == '0';
+		update_tree_entry(&desc);
+
+		switch (mode) {
+		/*
+		 * Standard modes..
+		 */
+		case S_IFREG | 0755:
+		case S_IFREG | 0644:
+		case S_IFLNK:
+		case S_IFDIR:
+		case S_IFGITLINK:
+			break;
+		/*
+		 * This is nonstandard, but we had a few of these
+		 * early on when we honored the full set of mode
+		 * bits..
+		 */
+		case S_IFREG | 0664:
+			if (!strict)
+				break;
+		default:
+			has_bad_modes = 1;
+		}
+
+		if (o_name) {
+			switch (verify_ordered(o_mode, o_name, mode, name)) {
+			case TREE_UNORDERED:
+				not_properly_sorted = 1;
+				break;
+			case TREE_HAS_DUPS:
+				has_dup_entries = 1;
+				break;
+			default:
+				break;
+			}
+		}
+
+		o_mode = mode;
+		o_name = name;
+		o_sha1 = sha1;
+	}
+
+	retval = 0;
+	if (has_full_path)
+		retval += error_func(&item->object, FSCK_WARN, "contains full pathnames");
+	if (has_empty_name)
+		retval += error_func(&item->object, FSCK_WARN, "contains empty pathname");
+	if (has_zero_pad)
+		retval += error_func(&item->object, FSCK_WARN, "contains zero-padded file modes");
+	if (has_bad_modes)
+		retval += error_func(&item->object, FSCK_WARN, "contains bad file modes");
+	if (has_dup_entries)
+		retval += error_func(&item->object, FSCK_ERROR, "contains duplicate file entries");
+	if (not_properly_sorted)
+		retval += error_func(&item->object, FSCK_ERROR, "not properly sorted");
+	return retval;
+}
+
+static int fsck_commit(struct commit *commit, fsck_error error_func)
+{
+	char *buffer = commit->buffer;
+	unsigned char tree_sha1[20], sha1[20];
+	struct commit_graft *graft;
+	int parents = 0;
+
+	if (!commit->date)
+		return error_func(&commit->object, FSCK_ERROR, "invalid author/committer line");
+
+	if (memcmp(buffer, "tree ", 5))
+		return error_func(&commit->object, FSCK_ERROR, "invalid format - expected 'tree' line");
+	if (get_sha1_hex(buffer+5, tree_sha1) || buffer[45] != '\n')
+		return error_func(&commit->object, FSCK_ERROR, "invalid 'tree' line format - bad sha1");
+	buffer += 46;
+	while (!memcmp(buffer, "parent ", 7)) {
+		if (get_sha1_hex(buffer+7, sha1) || buffer[47] != '\n')
+			return error_func(&commit->object, FSCK_ERROR, "invalid 'parent' line format - bad sha1");
+		buffer += 48;
+		parents++;
+	}
+	graft = lookup_commit_graft(commit->object.sha1);
+	if (graft) {
+		struct commit_list *p = commit->parents;
+		parents = 0;
+		while (p) {
+			p = p->next;
+			parents++;
+		}
+		if (graft->nr_parent == -1 && !parents)
+			; /* shallow commit */
+		else if (graft->nr_parent != parents)
+			return error_func(&commit->object, FSCK_ERROR, "graft objects missing");
+	} else {
+		struct commit_list *p = commit->parents;
+		while (p && parents) {
+			p = p->next;
+			parents--;
+		}
+		if (p || parents)
+			return error_func(&commit->object, FSCK_ERROR, "parent objects missing");
+	}
+	if (memcmp(buffer, "author ", 7))
+		return error_func(&commit->object, FSCK_ERROR, "invalid format - expected 'author' line");
+	if (!commit->tree)
+		return error_func(&commit->object, FSCK_ERROR, "could not load commit's tree %s", sha1_to_hex(tree_sha1));
+
+	return 0;
+}
+
+static int fsck_tag(struct tag *tag, fsck_error error_func)
+{
+	struct object *tagged = tag->tagged;
+
+	if (!tagged)
+		return error_func(&tag->object, FSCK_ERROR, "could not load tagged object");
+	return 0;
+}
+
+int fsck_object(struct object *obj, int strict, fsck_error error_func)
+{
+	if (!obj)
+		return error_func(obj, FSCK_ERROR, "no valid object to fsck");
+
+	if (obj->type == OBJ_BLOB)
+		return 0;
+	if (obj->type == OBJ_TREE)
+		return fsck_tree((struct tree *) obj, strict, error_func);
+	if (obj->type == OBJ_COMMIT)
+		return fsck_commit((struct commit *) obj, error_func);
+	if (obj->type == OBJ_TAG)
+		return fsck_tag((struct tag *) obj, error_func);
+
+	return error_func(obj, FSCK_ERROR, "unknown type '%d' (internal fsck error)",
+			  obj->type);
+}