submodule config cache API
==========================

The submodule config cache API allows to read submodule
configurations/information from specified revisions. Internally
information is lazily read into a cache that is used to avoid
unnecessary parsing of the same .gitmodule files. Lookups can be done by
submodule path or name.

Usage
-----

The caller can look up information about submodules by using the
`submodule_from_path()` or `submodule_from_name()` functions. They return
a `struct submodule` which contains the values. The API automatically
initializes and allocates the needed infrastructure on-demand.

If the internal cache might grow too big or when the caller is done with
the API, all internally cached values can be freed with submodule_free().

Data Structures
---------------

`struct submodule`::

	This structure is used to return the information about one
	submodule for a certain revision. It is returned by the lookup
	functions.

Functions
---------

`void submodule_free()`::

	Use these to free the internally cached values.

`const struct submodule *submodule_from_path(const unsigned char *commit_sha1, const char *path)`::

	Lookup values for one submodule by its commit_sha1 and path.

`const struct submodule *submodule_from_name(const unsigned char *commit_sha1, const char *name)`::

	The same as above but lookup by name.

For an example usage see test-submodule-config.c.