Meta

The Meta record carries information about the stone itself or other binary packages, hence the name “meta”. It is composed of a 8 bytes long header-like section, plus a value of variable length. The information it carries is strongly typed.

Some of its fields can only be found in Repository stones, since they are information about packages to download.

Field	Type	Size (bytes)	Description
length	uint	4	Length, in bytes, of the value that follows the header-like section.
tag	uint	2	What information this record carries about the stone.
kind	uint	1	The base type of the information, for proper encoding and decoding.
padding	blob	1	Unused.
value	blob	length	Value of the information. The encoding depends on the value of kind.

tag

tag is an enum.

Value	Name	Description
1	Name	Name of the stone, which is typically the name of a package to install or remove.
2	Architecture	Target hardware architecture of the package.
3	Version	Version of the package.
4	Summary	Succinct description of a package.
5	Description	Full length description of the package.
6	Homepage	Web homepage of the project being packaged.
7	SourceID	ID of the source package, used for grouping.
8	Depends	One dependency of the package.
9	Provides	One capability, or the name, of the package. See further paragraphs for details.
10	Conflicts	One capability, or name of another package, that conflicts with this package.
11	Release	Release number of the package. It differs from Version in that Version identifies a state of the upstream project. Release is an increasing number that relates to the package.
12	License	One license under which the upstream project is released, in SPDX format.
13	BuildRelease	Uniquely identifies a rebuild of a stone. It is an increasing number.
14	PackageURI	URL relative to the base repository URL, where to download a package from. It is specific to a Repository stone.
15	PackageHash	SHA-256 hash of a whole package stone. It is specific to a Repository stone.
16	PackageSize	Size, in bytes, of a package when installed on disk (assumed when the CAS is empty, thus without de-duplication). It is specific to a Repository stone.
17	BuildDepends	Build-time dependency of a package.
18	SourceURI	Upstream URL for the source archive of a package.
19	SourcePath	Relative path for the source within the upstream URL.
20	SourceRef	Git commit or ref of the upstream source.

kind

kind is an enum.

Value	Name	Description
1	Int8	int, 1 byte long.
2	Uint8	uint, 1 byte long.
3	Int16	int, 2 bytes long.
4	Uint16	uint, 2 bytes long.
5	Int32	int, 4 bytes long.
6	Uint32	uint, 4 bytes long.
7	Int64	int, 8 bytes long.
8	Uint64	uint, 8 bytes long.
9	String	String.
10	Dependency	PackageReference structure.
11	Provider	PackageReference structure.

PackageReference

As explained before, the encoding format of value is explicated by the kind enum. Most of the kinds are a characterization of a base format, but there is one outstanding kind: PackageReference. Below is the format of PackageReference.

Field	Type	Size (bytes)	Description
kind	uint	1	Kind of package one depends on, or provides.
name	str	length - 1	Value of the reference.

kind

PackageReference’s kind field is an enum.

Value	Name	Description
0	PackageName	A package depends on, or provides, a package name.
1	SharedLibrary	A package depends on, or provides, a shared library (*.so file).
2	PkgConfig	A package depends on, or provides, a pkg-config target.
3	Interpreter	A package depends on, or provides, a program interpreter (i.e. an ELF binary with PT_INTERP set).
4	CMake	A package depends on, or provides, a CMake target.
5	Python	A package depends on, or provides, a Python module.
6	BinaryDep	A package depends on, or provides, a binary file in /usr/bin.
7	SystemBinary	A package depends on, or provides, a binary file in /usr/sbin.
8	PkgConfig32	Like PkgConfig, but emul32-compatible.