git/object.h
Jeff King 75a9549047 avoid segfaults on parse_object failure
Many call-sites of parse_object assume that they will get a
non-NULL return value; this is not the case if we encounter
an error while parsing the object.

This patch adds a wrapper function around parse_object that
handles dying automatically, and uses it anywhere we
immediately try to access the return value as a non-NULL
pointer (i.e., anywhere that we would currently segfault).

This wrapper may also be useful in other places. The most
obvious one is code like:

  o = parse_object(sha1);
  if (!o)
	  die(...);

However, these should not be mechanically converted to
parse_object_or_die, as the die message is sometimes
customized. Later patches can address these sites on a
case-by-case basis.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-03-17 12:49:03 -07:00

93 lines
2.8 KiB
C

#ifndef OBJECT_H
#define OBJECT_H
struct object_list {
struct object *item;
struct object_list *next;
};
struct object_array {
unsigned int nr;
unsigned int alloc;
struct object_array_entry {
struct object *item;
const char *name;
unsigned mode;
} *objects;
};
#define OBJECT_ARRAY_INIT { 0, 0, NULL }
#define TYPE_BITS 3
#define FLAG_BITS 27
/*
* The object type is stored in 3 bits.
*/
struct object {
unsigned parsed : 1;
unsigned used : 1;
unsigned type : TYPE_BITS;
unsigned flags : FLAG_BITS;
unsigned char sha1[20];
};
extern const char *typename(unsigned int type);
extern int type_from_string(const char *str);
extern unsigned int get_max_object_index(void);
extern struct object *get_indexed_object(unsigned int);
/*
* This can be used to see if we have heard of the object before, but
* it can return "yes we have, and here is a half-initialised object"
* for an object that we haven't loaded/parsed yet.
*
* When parsing a commit to create an in-core commit object, its
* parents list holds commit objects that represent its parents, but
* they are expected to be lazily initialized and do not know what
* their trees or parents are yet. When this function returns such a
* half-initialised objects, the caller is expected to initialize them
* by calling parse_object() on them.
*/
struct object *lookup_object(const unsigned char *sha1);
extern void *create_object(const unsigned char *sha1, int type, void *obj);
/*
* Returns the object, having parsed it to find out what it is.
*
* Returns NULL if the object is missing or corrupt.
*/
struct object *parse_object(const unsigned char *sha1);
/*
* Like parse_object, but will die() instead of returning NULL. If the
* "name" parameter is not NULL, it is included in the error message
* (otherwise, the sha1 hex is given).
*/
struct object *parse_object_or_die(const unsigned char *sha1, const char *name);
/* Given the result of read_sha1_file(), returns the object after
* parsing it. eaten_p indicates if the object has a borrowed copy
* of buffer and the caller should not free() it.
*/
struct object *parse_object_buffer(const unsigned char *sha1, enum object_type type, unsigned long size, void *buffer, int *eaten_p);
/** Returns the object, with potentially excess memory allocated. **/
struct object *lookup_unknown_object(const unsigned char *sha1);
struct object_list *object_list_insert(struct object *item,
struct object_list **list_p);
int object_list_contains(struct object_list *list, struct object *obj);
/* Object array handling .. */
void add_object_array(struct object *obj, const char *name, struct object_array *array);
void add_object_array_with_mode(struct object *obj, const char *name, struct object_array *array, unsigned mode);
void object_array_remove_duplicates(struct object_array *);
void clear_object_flags(unsigned flags);
#endif /* OBJECT_H */