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#include "types.hh"
#include "hash.hh"
#include <variant>
namespace nix {
/* Flake references are a URI-like syntax to specify a flake.
Examples:
* <flake-id>(/rev-or-ref(/rev)?)?
Look up a flake by ID in the flake lock file or in the flake
registry. These must specify an actual location for the flake
using the formats listed below. Note that in pure evaluation
mode, the flake registry is empty.
Optionally, the rev or ref from the dereferenced flake can be
overriden. For example,
nixpkgs/19.09
uses the "19.09" branch of the nixpkgs' flake GitHub repository,
while
nixpkgs/98a2a5b5370c1e2092d09cb38b9dcff6d98a109f
uses the specified revision. For Git (rather than GitHub)
repositories, both the rev and ref must be given, e.g.
nixpkgs/19.09/98a2a5b5370c1e2092d09cb38b9dcff6d98a109f
* github:<owner>/<repo>(/<rev-or-ref>)?
A repository on GitHub. These differ from Git references in that
they're downloaded in a efficient way (via the tarball mechanism)
and that they support downloading a specific revision without
specifying a branch. <rev-or-ref> is either a commit hash ("rev")
or a branch or tag name ("ref"). The default is: "master" if none
is specified. Note that in pure evaluation mode, a commit hash
must be used.
Flakes fetched in this manner expose "rev" and "lastModified"
attributes, but not "revCount".
Examples:
github:edolstra/dwarffs
github:edolstra/dwarffs/unstable
github:edolstra/dwarffs/41c0c1bf292ea3ac3858ff393b49ca1123dbd553
* https://<server>/<path>.git(\?attr(&attr)*)?
ssh://<server>/<path>.git(\?attr(&attr)*)?
git://<server>/<path>.git(\?attr(&attr)*)?
file:///<path>(\?attr(&attr)*)?
where 'attr' is one of:
rev=<rev>
ref=<ref>
A Git repository fetched through https. Note that the path must
end in ".git". The default for "ref" is "master".
Examples:
https://example.org/my/repo.git
https://example.org/my/repo.git?ref=release-1.2.3
https://example.org/my/repo.git?rev=e72daba8250068216d79d2aeef40d4d95aff6666
* /path.git(\?attr(&attr)*)?
Like file://path.git, but if no "ref" or "rev" is specified, the
(possibly dirty) working tree will be used. Using a working tree
is not allowed in pure evaluation mode.
Examples:
/path/to/my/repo
/path/to/my/repo?ref=develop
/path/to/my/repo?rev=e72daba8250068216d79d2aeef40d4d95aff6666
* https://<server>/<path>.tar.xz(?hash=<sri-hash>)
file:///<path>.tar.xz(?hash=<sri-hash>)
A flake distributed as a tarball. In pure evaluation mode, an SRI
hash is mandatory. It exposes a "lastModified" attribute, being
the newest file inside the tarball.
Example:
https://releases.nixos.org/nixos/unstable/nixos-19.03pre167858.f2a1a4e93be/nixexprs.tar.xz
https://releases.nixos.org/nixos/unstable/nixos-19.03pre167858.f2a1a4e93be/nixexprs.tar.xz?hash=sha256-56bbc099995ea8581ead78f22832fee7dbcb0a0b6319293d8c2d0aef5379397c
Note: currently, there can be only one flake per Git repository, and
it must be at top-level. In the future, we may want to add a field
(e.g. "dir=<dir>") to specify a subdirectory inside the repository.
*/
typedef std::string FlakeId;
struct FlakeRef
{
struct IsFlakeId
{
FlakeId id;
std::optional<std::string> ref;
std::optional<Hash> rev;
};
struct IsGitHub
{
std::string owner, repo;
std::optional<std::string> ref;
std::optional<Hash> rev;
};
struct IsGit
{
std::string uri;
std::optional<std::string> ref;
std::optional<Hash> rev;
};
struct IsPath
{
Path path;
};
// Git, Tarball
std::variant<IsFlakeId, IsGitHub, IsGit, IsPath> data;
// Parse a flake URI.
FlakeRef(const std::string & uri);
// Default constructor
FlakeRef(const FlakeRef & flakeRef) : data(flakeRef.data) {};
/* Unify two flake references so that the resulting reference
combines the information from both. For example,
"nixpkgs/<hash>" and "github:NixOS/nixpkgs" unifies to
"nixpkgs/master". May throw an exception if the references are
incompatible (e.g. "nixpkgs/<hash1>" and "nixpkgs/<hash2>",
where hash1 != hash2). */
FlakeRef(const FlakeRef & a, const FlakeRef & b);
// FIXME: change to operator <<.
std::string to_string() const;
/* Check whether this is a "direct" flake reference, that is, not
a flake ID, which requires a lookup in the flake registry. */
bool isDirect() const
{
return !std::get_if<FlakeRef::IsFlakeId>(&data);
}
/* Check whether this is an "immutable" flake reference, that is,
one that contains a commit hash or content hash. */
bool isImmutable() const;
FlakeRef baseRef() const;
};
}
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