Nix/src/libfetchers/cache.hh
Eelco Dolstra 462421d345 Backport libfetchers from the flakes branch
This provides a pluggable mechanism for defining new fetchers. It adds
a builtin function 'fetchTree' that generalizes existing fetchers like
'fetchGit', 'fetchMercurial' and 'fetchTarball'. 'fetchTree' takes a
set of attributes, e.g.

  fetchTree {
    type = "git";
    url = "https://example.org/repo.git";
    ref = "some-branch";
    rev = "abcdef...";
  }

The existing fetchers are just wrappers around this. Note that the
input attributes to fetchTree are the same as flake input
specifications and flake lock file entries.

All fetchers share a common cache stored in
~/.cache/nix/fetcher-cache-v1.sqlite. This replaces the ad hoc caching
mechanisms in fetchGit and download.cc (e.g. ~/.cache/nix/{tarballs,git-revs*}).

This also adds support for Git worktrees (c169ea5904).
2020-04-07 09:03:14 +02:00

35 lines
642 B
C++

#pragma once
#include "fetchers.hh"
namespace nix::fetchers {
struct Cache
{
virtual void add(
ref<Store> store,
const Attrs & inAttrs,
const Attrs & infoAttrs,
const StorePath & storePath,
bool immutable) = 0;
virtual std::optional<std::pair<Attrs, StorePath>> lookup(
ref<Store> store,
const Attrs & inAttrs) = 0;
struct Result
{
bool expired = false;
Attrs infoAttrs;
StorePath storePath;
};
virtual std::optional<Result> lookupExpired(
ref<Store> store,
const Attrs & inAttrs) = 0;
};
ref<Cache> getCache();
}