nix-super/src/libstore/remote-fs-accessor.hh
regnat 7080321618 Use the fs accessor for readInvalidDerivation
Extend `FSAccessor::readFile` to allow not checking that the path is a
valid one, and rewrite `readInvalidDerivation` using this extended
`readFile`.

Several places in the code use `readInvalidDerivation`, either because
they need to read a derivation that has been written in the store but
not registered yet, or more generally to prevent a deadlock because
`readDerivation` tries to lock the state, so can't be called from a
place where the lock is already held.
However, `readInvalidDerivation` implicitely assumes that the store is a
`LocalFSStore`, which isn't always the case.

The concrete motivation for this is that it's required for `nix copy
--from someBinaryCache` to work, which is tremendously useful for the
tests.
2020-12-15 20:10:46 +01:00

40 lines
921 B
C++

#pragma once
#include "fs-accessor.hh"
#include "ref.hh"
#include "store-api.hh"
namespace nix {
class RemoteFSAccessor : public FSAccessor
{
ref<Store> store;
std::map<std::string, ref<FSAccessor>> nars;
Path cacheDir;
std::pair<ref<FSAccessor>, Path> fetch(const Path & path_, bool requireValidPath = true);
friend class BinaryCacheStore;
Path makeCacheFile(std::string_view hashPart, const std::string & ext);
void addToCache(std::string_view hashPart, const std::string & nar,
ref<FSAccessor> narAccessor);
public:
RemoteFSAccessor(ref<Store> store,
const /* FIXME: use std::optional */ Path & cacheDir = "");
Stat stat(const Path & path) override;
StringSet readDirectory(const Path & path) override;
std::string readFile(const Path & path, bool requireValidPath = true) override;
std::string readLink(const Path & path) override;
};
}