[PATCH] Add function to parse an object of unspecified type (take 2)

This adds a function that parses an object from the database when we have
to look up its actual type. It also checks the hash of the file, due to
its heritage as part of fsck-cache.

Signed-Off-By: Daniel Barkalow <barkalow@iabervon.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

object.c

@@ -1,5 +1,9 @@
 #include "object.h"
+#include "blob.h"
+#include "tree.h"
+#include "commit.h"
 #include "cache.h"
+#include "tag.h"
 #include <stdlib.h>
 #include <string.h>
 
@@ -94,3 +98,39 @@ void mark_reachable(struct object *obj, unsigned int mask)
 		p = p->next;
 	}
 }
+
+struct object *parse_object(unsigned char *sha1)
+{
+	unsigned long mapsize;
+	void *map = map_sha1_file(sha1, &mapsize);
+	if (map) {
+		char type[100];
+		unsigned long size;
+		void *buffer = unpack_sha1_file(map, mapsize, type, &size);
+		if (!buffer)
+			return NULL;
+		if (check_sha1_signature(sha1, buffer, size, type) < 0)
+			printf("sha1 mismatch %s\n", sha1_to_hex(sha1));
+		munmap(map, mapsize);
+		if (!strcmp(type, "blob")) {
+			struct blob *ret = lookup_blob(sha1);
+			parse_blob(ret);
+			return &ret->object;
+		} else if (!strcmp(type, "tree")) {
+			struct tree *ret = lookup_tree(sha1);
+			parse_tree(ret);
+			return &ret->object;
+		} else if (!strcmp(type, "commit")) {
+			struct commit *ret = lookup_commit(sha1);
+			parse_commit(ret);
+			return &ret->object;
+		} else if (!strcmp(type, "tag")) {
+			struct tag *ret = lookup_tag(sha1);
+			parse_tag(ret);
+			return &ret->object;
+		} else {
+			return NULL;
+		}
+	}
+	return NULL;
+}

object.h

@@ -22,6 +22,9 @@ struct object *lookup_object(unsigned char *sha1);
 
 void created_object(unsigned char *sha1, struct object *obj);
 
+/** Returns the object, having parsed it to find out what it is. **/
+struct object *parse_object(unsigned char *sha1);
+
 void add_ref(struct object *refer, struct object *target);
 
 void mark_reachable(struct object *obj, unsigned int mask);