thodg/libgit2

diff --git a/src/diff_output.c b/src/diff_output.c
index 8873a4d..dbef7dd 100644
--- a/src/diff_output.c
+++ b/src/diff_output.c
@@ -292,6 +292,7 @@ static int get_blob_content(
 	git_blob **blob)
 {
 	int error;
+	git_odb_object *odb_obj = NULL;
 
 	if (git_oid_iszero(&file->oid))
 		return 0;
@@ -303,7 +304,8 @@ static int get_blob_content(
 
 		/* peek at object header to avoid loading if too large */
 		if ((error = git_repository_odb__weakptr(&odb, ctxt->repo)) < 0 ||
-			(error = git_odb_read_header(&len, &type, odb, &file->oid)) < 0)
+			(error = git_odb__read_header_or_object(
+				&odb_obj, &len, &type, odb, &file->oid)) < 0)
 			return error;
 
 		assert(type == GIT_OBJ_BLOB);
@@ -317,7 +319,14 @@ static int get_blob_content(
 	if (ctxt->delta->binary == 1)
 		return 0;
 
-	if ((error = git_blob_lookup(blob, ctxt->repo, &file->oid)) < 0)
+	if (odb_obj != NULL) {
+		error = git_object__from_odb_object(
+			(git_object **)blob, ctxt->repo, odb_obj, GIT_OBJ_BLOB);
+		git_odb_object_free(odb_obj);
+	} else
+		error = git_blob_lookup(blob, ctxt->repo, &file->oid);
+
+	if (error)
 		return error;
 
 	map->data = (void *)git_blob_rawcontent(*blob);
diff --git a/src/object.c b/src/object.c
index 5130d97..2e45eb8 100644
--- a/src/object.c
+++ b/src/object.c
@@ -77,6 +77,58 @@ static int create_object(git_object **object_out, git_otype type)
 	return 0;
 }
 
+int git_object__from_odb_object(
+	git_object **object_out,
+	git_repository *repo,
+	git_odb_object *odb_obj,
+	git_otype type)
+{
+	int error;
+	git_object *object = NULL;
+
+	if (type != GIT_OBJ_ANY && type != odb_obj->raw.type) {
+		giterr_set(GITERR_ODB, "The requested type does not match the type in the ODB");
+		return GIT_ENOTFOUND;
+	}
+
+	type = odb_obj->raw.type;
+
+	if ((error = create_object(&object, type)) < 0)
+		return error;
+
+	/* Initialize parent object */
+	git_oid_cpy(&object->cached.oid, &odb_obj->cached.oid);
+	object->repo = repo;
+
+	switch (type) {
+	case GIT_OBJ_COMMIT:
+		error = git_commit__parse((git_commit *)object, odb_obj);
+		break;
+
+	case GIT_OBJ_TREE:
+		error = git_tree__parse((git_tree *)object, odb_obj);
+		break;
+
+	case GIT_OBJ_TAG:
+		error = git_tag__parse((git_tag *)object, odb_obj);
+		break;
+
+	case GIT_OBJ_BLOB:
+		error = git_blob__parse((git_blob *)object, odb_obj);
+		break;
+
+	default:
+		break;
+	}
+
+	if (error < 0)
+		git_object__free(object);
+	else
+		*object_out = git_cache_try_store(&repo->objects, object);
+
+	return error;
+}
+
 int git_object_lookup_prefix(
 	git_object **object_out,
 	git_repository *repo,
@@ -148,53 +200,11 @@ int git_object_lookup_prefix(
 	if (error < 0)
 		return error;
 
-	if (type != GIT_OBJ_ANY && type != odb_obj->raw.type) {
-		git_odb_object_free(odb_obj);
-		giterr_set(GITERR_ODB, "The given type does not match the type on the ODB");
-		return GIT_ENOTFOUND;
-	}
-
-	type = odb_obj->raw.type;
-
-	if (create_object(&object, type) < 0) {
-		git_odb_object_free(odb_obj);
-		return -1;
-	}
-
-	/* Initialize parent object */
-	git_oid_cpy(&object->cached.oid, &odb_obj->cached.oid);
-	object->repo = repo;
-
-	switch (type) {
-	case GIT_OBJ_COMMIT:
-		error = git_commit__parse((git_commit *)object, odb_obj);
-		break;
-
-	case GIT_OBJ_TREE:
-		error = git_tree__parse((git_tree *)object, odb_obj);
-		break;
-
-	case GIT_OBJ_TAG:
-		error = git_tag__parse((git_tag *)object, odb_obj);
-		break;
-
-	case GIT_OBJ_BLOB:
-		error = git_blob__parse((git_blob *)object, odb_obj);
-		break;
-
-	default:
-		break;
-	}
+	error = git_object__from_odb_object(object_out, repo, odb_obj, type);
 
 	git_odb_object_free(odb_obj);
 
-	if (error < 0) {
-		git_object__free(object);
-		return -1;
-	}
-
-	*object_out = git_cache_try_store(&repo->objects, object);
-	return 0;
+	return error;
 }
 
 int git_object_lookup(git_object **object_out, git_repository *repo, const git_oid *id, git_otype type) {
diff --git a/src/object.h b/src/object.h
new file mode 100644
index 0000000..bc12aad
--- /dev/null
+++ b/src/object.h
@@ -0,0 +1,39 @@
+/*
+ * 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.
+ */
+#ifndef INCLUDE_object_h__
+#define INCLUDE_object_h__
+
+/** Base git object for inheritance */
+struct git_object {
+	git_cached_obj cached;
+	git_repository *repo;
+	git_otype type;
+};
+
+/* fully free the object; internal method, DO NOT EXPORT */
+void git_object__free(void *object);
+
+GIT_INLINE(int) git_object__dup(git_object **dest, git_object *source)
+{
+	git_cached_obj_incref(source);
+	*dest = source;
+	return 0;
+}
+
+int git_object__from_odb_object(
+	git_object **object_out,
+	git_repository *repo,
+	git_odb_object *odb_obj,
+	git_otype type);
+
+int git_object__resolve_to_type(git_object **obj, git_otype type);
+
+int git_oid__parse(git_oid *oid, const char **buffer_out, const char *buffer_end, const char *header);
+
+void git_oid__writebuf(git_buf *buf, const char *header, const git_oid *oid);
+
+#endif
diff --git a/src/odb.c b/src/odb.c
index 83c7a80..0e03e40 100644
--- a/src/odb.c
+++ b/src/odb.c
@@ -514,19 +514,36 @@ int git_odb_exists(git_odb *db, const git_oid *id)
 
 int git_odb_read_header(size_t *len_p, git_otype *type_p, git_odb *db, const git_oid *id)
 {
+	int error;
+	git_odb_object *object;
+
+	error = git_odb__read_header_or_object(&object, len_p, type_p, db, id);
+
+	if (object)
+		git_odb_object_free(object);
+
+	return error;
+}
+
+int git_odb__read_header_or_object(
+	git_odb_object **out, size_t *len_p, git_otype *type_p,
+	git_odb *db, const git_oid *id)
+{
 	unsigned int i;
 	int error = GIT_ENOTFOUND;
 	git_odb_object *object;
 
-	assert(db && id);
+	assert(db && id && out && len_p && type_p);
 
 	if ((object = git_cache_get(&db->cache, id)) != NULL) {
 		*len_p = object->raw.len;
 		*type_p = object->raw.type;
-		git_odb_object_free(object);
+		*out = object;
 		return 0;
 	}
 
+	*out = NULL;
+
 	for (i = 0; i < db->backends.length && error < 0; ++i) {
 		backend_internal *internal = git_vector_get(&db->backends, i);
 		git_odb_backend *b = internal->backend;
@@ -547,7 +564,8 @@ int git_odb_read_header(size_t *len_p, git_otype *type_p, git_odb *db, const git
 
 	*len_p = object->raw.len;
 	*type_p = object->raw.type;
-	git_odb_object_free(object);
+	*out = object;
+
 	return 0;
 }
 
diff --git a/src/odb.h b/src/odb.h
index 696e129..e9e33dd 100644
--- a/src/odb.h
+++ b/src/odb.h
@@ -84,4 +84,12 @@ int git_odb__error_notfound(const char *message, const git_oid *oid);
  */
 int git_odb__error_ambiguous(const char *message);
 
+/*
+ * Attempt to read object header or just return whole object if it could
+ * not be read.
+ */
+int git_odb__read_header_or_object(
+	git_odb_object **out, size_t *len_p, git_otype *type_p,
+	git_odb *db, const git_oid *id);
+
 #endif
diff --git a/src/repository.h b/src/repository.h
index 4695edf..82988ba 100644
--- a/src/repository.h
+++ b/src/repository.h
@@ -18,6 +18,7 @@
 #include "refs.h"
 #include "buffer.h"
 #include "odb.h"
+#include "object.h"
 #include "attr.h"
 #include "strmap.h"
 
@@ -75,13 +76,6 @@ enum {
 	GIT_REPOSITORY_INIT__IS_REINIT  = (1u << 18),
 };
 
-/** Base git object for inheritance */
-struct git_object {
-	git_cached_obj cached;
-	git_repository *repo;
-	git_otype type;
-};
-
 /** Internal structure for repository object */
 struct git_repository {
 	git_odb *_odb;
@@ -102,21 +96,6 @@ struct git_repository {
 	git_cvar_value cvar_cache[GIT_CVAR_CACHE_MAX];
 };
 
-/* fully free the object; internal method, DO NOT EXPORT */
-void git_object__free(void *object);
-
-GIT_INLINE(int) git_object__dup(git_object **dest, git_object *source)
-{
-	git_cached_obj_incref(source);
-	*dest = source;
-	return 0;
-}
-
-int git_object__resolve_to_type(git_object **obj, git_otype type);
-
-int git_oid__parse(git_oid *oid, const char **buffer_out, const char *buffer_end, const char *header);
-void git_oid__writebuf(git_buf *buf, const char *header, const git_oid *oid);
-
 GIT_INLINE(git_attr_cache *) git_repository_attr_cache(git_repository *repo)
 {
 	return &repo->attrcache;
@@ -136,7 +115,7 @@ int git_repository_odb__weakptr(git_odb **out, git_repository *repo);
 int git_repository_index__weakptr(git_index **out, git_repository *repo);
 
 /*
- * CVAR cache 
+ * CVAR cache
  *
  * Efficient access to the most used config variables of a repository.
  * The cache is cleared everytime the config backend is replaced.