git/replace-object.h

#ifndef REPLACE_OBJECT_H
#define REPLACE_OBJECT_H

#include "oidmap.h"
#include "repository.h"
#include "object-store.h"

/*
 * Do replace refs need to be checked this run?  This variable is
 * initialized to true unless --no-replace-object is used or
 * $GIT_NO_REPLACE_OBJECTS is set, but is set to false by some
 * commands that do not want replace references to be active.
 */
extern int read_replace_refs;

struct replace_object {
	struct oidmap_entry original;
	struct object_id replacement;
};

void prepare_replace_object(struct repository *r);

/*
 * This internal function is only declared here for the benefit of
 * lookup_replace_object().  Please do not call it directly.
 */
const struct object_id *do_lookup_replace_object(struct repository *r,
						 const struct object_id *oid);

/*
 * If object sha1 should be replaced, return the replacement object's
 * name (replaced recursively, if necessary).  The return value is
 * either sha1 or a pointer to a permanently-allocated value.  When
 * object replacement is suppressed, always return sha1.
 *
 * Note: some thread debuggers might point a data race on the
 * replace_map_initialized reading in this function. However, we know there's no
 * problem in the value being updated by one thread right after another one read
 * it here (and it should be written to only once, anyway).
 */
static inline const struct object_id *lookup_replace_object(struct repository *r,
							    const struct object_id *oid)
{
	if (!read_replace_refs ||
	    (r->objects->replace_map_initialized &&
	     r->objects->replace_map->map.tablesize == 0))
		return oid;
	return do_lookup_replace_object(r, oid);
}

#endif /* REPLACE_OBJECT_H */