git/tmp-objdir.h
Jeff King 2564d994c9 tmp-objdir: introduce API for temporary object directories
Once objects are added to the object database by a process,
they cannot easily be deleted, as we don't know what other
processes may have started referencing them. We have to
clean them up with git-gc, which will apply the usual
reachability and grace-period checks.

This patch provides an alternative: it helps callers create
a temporary directory inside the object directory, and a
temporary environment which can be passed to sub-programs to
ask them to write there (the original object directory
remains accessible as an alternate of the temporary one).

See tmp-objdir.h for details on the API.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-10-10 13:54:02 -07:00

55 lines
1.5 KiB
C

#ifndef TMP_OBJDIR_H
#define TMP_OBJDIR_H
/*
* This API allows you to create a temporary object directory, advertise it to
* sub-processes via GIT_OBJECT_DIRECTORY and GIT_ALTERNATE_OBJECT_DIRECTORIES,
* and then either migrate its object into the main object directory, or remove
* it. The library handles unexpected signal/exit death by cleaning up the
* temporary directory.
*
* Example:
*
* struct tmp_objdir *t = tmp_objdir_create();
* if (!run_command_v_opt_cd_env(cmd, 0, NULL, tmp_objdir_env(t)) &&
* !tmp_objdir_migrate(t))
* printf("success!\n");
* else
* die("failed...tmp_objdir will clean up for us");
*
*/
struct tmp_objdir;
/*
* Create a new temporary object directory; returns NULL on failure.
*/
struct tmp_objdir *tmp_objdir_create(void);
/*
* Return a list of environment strings, suitable for use with
* child_process.env, that can be passed to child programs to make use of the
* temporary object directory.
*/
const char **tmp_objdir_env(const struct tmp_objdir *);
/*
* Finalize a temporary object directory by migrating its objects into the main
* object database, removing the temporary directory, and freeing any
* associated resources.
*/
int tmp_objdir_migrate(struct tmp_objdir *);
/*
* Destroy a temporary object directory, discarding any objects it contains.
*/
int tmp_objdir_destroy(struct tmp_objdir *);
/*
* Add the temporary object directory as an alternate object store in the
* current process.
*/
void tmp_objdir_add_as_alternate(const struct tmp_objdir *);
#endif /* TMP_OBJDIR_H */