Add .PKGINFO parser

Add a parser for .PKGINFO files.

Fixes #53 (closed)

Fixes #24 (closed)

docs/packages/contents.rst

@@ -84,6 +84,44 @@ BuildInfoV2
 .. literalinclude:: schema/BuildInfoV2.json
    :language: json
 
+.. _pkginfo:
+
+.PKGINFO
+--------
+
+The ``.PKGINFO`` files contained in packages describe their metadata.
+
+Formats for the file are specified by |makepkg|. Its |write_pkginfo()|
+function implements only the latest version of the available formats.
+
+.. _pkginfo json schema:
+
+PkgInfo
+^^^^^^^
+
+The entries in a ``.PKGINFO`` file are parsed and can subsequently be described
+by a JSON schema.
+
+Below is a list of currently understood versions of the schema.
+
+.. _pkginfov1:
+
+PkgInfoV1
+"""""""""
+
+.. literalinclude:: schema/PkgInfoV1.json
+   :language: json
+
+.. _pkginfov2:
+
+PkgInfoV2
+"""""""""
+
+In this version the ``pkgtype`` field has been added.
+
+.. literalinclude:: schema/PkgInfoV2.json
+   :language: json
+
 .. |mtree| raw:: html
 
   <a target="blank" href="https://man.archlinux.org/man/mtree.5">mtree</a>
@@ -100,6 +138,10 @@ BuildInfoV2
 
   <a target="blank" href="https://gitlab.archlinux.org/pacman/pacman/-/blob/bddfcc3f40ce1a19d4c9552cddbf2cab07c94d4b/scripts/makepkg.sh.in#L519-550">write_buildinfo()</a>
 
+.. |write_pkginfo()| raw:: html
+
+  <a target="blank" href="https://gitlab.archlinux.org/pacman/pacman/-/blob/bddfcc3f40ce1a19d4c9552cddbf2cab07c94d4b/scripts/makepkg.sh.in#L479-517">write_pkginfo()</a>
+
 .. |devtools| raw:: html
 
   <a target="blank" href="https://gitlab.archlinux.org/archlinux/devtools">devtools</a>