Add module for parsing .BUILDINFO files

This adds a module for parsing .BUILDINFO files.

Fixes #52 (closed)

docs/packages/contents.rst

@@ -40,6 +40,66 @@ MTreeEntryV1
 .. literalinclude:: schema/MTreeEntryV1.json
    :language: json
 
+.. _buildinfo:
+
+.BUILDINFO
+----------
+
+The ``.BUILDINFO`` files contained in packages are |BUILDINFO| files, which
+describe aspects of the build environment present during the creation of a
+package.
+
+Formats for the file are specified by |makepkg|. Its |write_buildinfo()|
+function implements only the latest version of the available formats.
+
+.. _buildinfo json schema:
+
+BuildInfo
+^^^^^^^^^
+
+The entries in a ``.BUILDINFO`` file are parsed and can subsequently be
+described by a JSON schema.
+
+Below is a list of currently understood versions of the schema.
+
+.. _buildinfov1:
+
+BuildInfoV1
+"""""""""""
+
+.. literalinclude:: schema/BuildInfoV1.json
+   :language: json
+
+.. _buildinfov2:
+
+BuildInfoV2
+"""""""""""
+
+.. note::
+
+  If |devtools| has been used as ``buildtool``, the ``buildtoolver`` has to be
+  of the form ``<optional_epoch><pkgver>-<pkgrel>-<arch>`` (e.g.
+  ``20220207-1-any``)!
+
+.. literalinclude:: schema/BuildInfoV2.json
+   :language: json
+
 .. |mtree| raw:: html
 
   <a target="blank" href="https://man.archlinux.org/man/mtree.5">mtree</a>
+
+.. |BUILDINFO| raw:: html
+
+  <a target="blank" href="https://man.archlinux.org/man/BUILDINFO.5">BUILDINFO</a>
+
+.. |makepkg| raw:: html
+
+  <a target="blank" href="https://man.archlinux.org/man/makepkg.8">makepkg</a>
+
+.. |write_buildinfo()| raw:: html
+
+  <a target="blank" href="https://gitlab.archlinux.org/pacman/pacman/-/blob/bddfcc3f40ce1a19d4c9552cddbf2cab07c94d4b/scripts/makepkg.sh.in#L519-550">write_buildinfo()</a>
+
+.. |devtools| raw:: html
+
+  <a target="blank" href="https://gitlab.archlinux.org/archlinux/devtools">devtools</a>