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authorVincent Ambo <mail@tazj.in>2022-05-18T15·39+0200
committerclbot <clbot@tvl.fyi>2022-05-19T14·08+0000
commitd127f9bd0e7b9b2e0df2de8a2227f77c0907468d (patch)
tree68455040d88b8e0c2817601db88ede450873ff8e /third_party/nix/src/libstore/store-api.hh
parentc85291c602ac666421627d6934ebc6d5be1b93e1 (diff)
chore(3p/nix): unvendor tvix 0.1 r/4098
Nothing is using this now, and we'll likely never pick this up again,
but we learned a lot in the process.

Every now and then this breaks in some bizarre way on channel bumps
and it's just a waste of time to maintain that.

Change-Id: Idcf2f5acd4ca7070ce18d7149cbfc0d967dc0a44
Reviewed-on: https://cl.tvl.fyi/c/depot/+/5632
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
Reviewed-by: lukegb <lukegb@tvl.fyi>
Autosubmit: tazjin <tazjin@tvl.su>
Diffstat (limited to 'third_party/nix/src/libstore/store-api.hh')
-rw-r--r--third_party/nix/src/libstore/store-api.hh816
1 files changed, 0 insertions, 816 deletions
diff --git a/third_party/nix/src/libstore/store-api.hh b/third_party/nix/src/libstore/store-api.hh
deleted file mode 100644
index eb18511e60df..000000000000
--- a/third_party/nix/src/libstore/store-api.hh
+++ /dev/null
@@ -1,816 +0,0 @@
-#pragma once
-
-#include <atomic>
-#include <limits>
-#include <map>
-#include <memory>
-#include <string>
-#include <unordered_map>
-#include <unordered_set>
-
-#include "libproto/worker.pb.h"
-#include "libstore/crypto.hh"
-#include "libstore/globals.hh"
-#include "libutil/config.hh"
-#include "libutil/hash.hh"
-#include "libutil/lru-cache.hh"
-#include "libutil/serialise.hh"
-#include "libutil/sync.hh"
-
-namespace nix {
-
-// Create a no-op stream buffer used to discard build output in cases
-// where we don't have a build log sink to thread through.
-//
-// TODO(tazjin): Get rid of this and do *something* with those logs.
-std::ostream DiscardLogsSink();
-
-MakeError(SubstError, Error);
-MakeError(BuildError, Error); /* denotes a permanent build failure */
-MakeError(InvalidPath, Error);
-MakeError(Unsupported, Error);
-MakeError(SubstituteGone, Error);
-MakeError(SubstituterDisabled, Error);
-
-struct BasicDerivation;
-struct Derivation;
-class FSAccessor;
-class NarInfoDiskCache;
-class Store;
-class JSONPlaceholder;
-
-enum RepairFlag : bool { NoRepair = false, Repair = true };
-enum CheckSigsFlag : bool { NoCheckSigs = false, CheckSigs = true };
-enum SubstituteFlag : bool { NoSubstitute = false, Substitute = true };
-enum AllowInvalidFlag : bool { DisallowInvalid = false, AllowInvalid = true };
-
-/* Size of the hash part of store paths, in base-32 characters. */
-const size_t storePathHashLen = 32;  // i.e. 160 bits
-
-/* Magic header of exportPath() output (obsolete). */
-const uint32_t exportMagic = 0x4558494e;
-
-using Roots = std::unordered_map<Path, std::unordered_set<std::string>>;
-
-struct GCOptions {
-  /* Garbage collector operation:
-
-     - `gcReturnLive': return the set of paths reachable from
-       (i.e. in the closure of) the roots.
-
-     - `gcReturnDead': return the set of paths not reachable from
-       the roots.
-
-     - `gcDeleteDead': actually delete the latter set.
-
-     - `gcDeleteSpecific': delete the paths listed in
-        `pathsToDelete', insofar as they are not reachable.
-  */
-  using GCAction = enum {
-    gcReturnLive,
-    gcReturnDead,
-    gcDeleteDead,
-    gcDeleteSpecific,
-  };
-
-  GCAction action{gcDeleteDead};
-
-  /* If `ignoreLiveness' is set, then reachability from the roots is
-     ignored (dangerous!).  However, the paths must still be
-     unreferenced *within* the store (i.e., there can be no other
-     store paths that depend on them). */
-  bool ignoreLiveness{false};
-
-  /* For `gcDeleteSpecific', the paths to delete. */
-  PathSet pathsToDelete;
-
-  /* Stop after at least `maxFreed' bytes have been freed. */
-  unsigned long long maxFreed{std::numeric_limits<unsigned long long>::max()};
-
-  [[nodiscard]] const proto::GCAction ActionToProto() const;
-};
-
-std::optional<GCOptions::GCAction> GCActionFromProto(
-    nix::proto::GCAction gc_action);
-
-struct GCResults {
-  /* Depending on the action, the GC roots, or the paths that would
-     be or have been deleted. */
-  PathSet paths;
-
-  /* For `gcReturnDead', `gcDeleteDead' and `gcDeleteSpecific', the
-     number of bytes that would be or was freed. */
-  unsigned long long bytesFreed = 0;
-};
-
-struct SubstitutablePathInfo {
-  Path deriver;
-  PathSet references;
-  unsigned long long downloadSize; /* 0 = unknown or inapplicable */
-  unsigned long long narSize;      /* 0 = unknown */
-};
-
-using SubstitutablePathInfos = std::map<Path, SubstitutablePathInfo>;
-
-struct ValidPathInfo {
-  Path path;
-  Path deriver;
-  Hash narHash;
-  PathSet references;
-  time_t registrationTime = 0;
-  uint64_t narSize = 0;  // 0 = unknown
-  uint64_t id;           // internal use only
-
-  /* Whether the path is ultimately trusted, that is, it's a
-     derivation output that was built locally. */
-  bool ultimate = false;
-
-  StringSet sigs;  // note: not necessarily verified
-
-  /* If non-empty, an assertion that the path is content-addressed,
-     i.e., that the store path is computed from a cryptographic hash
-     of the contents of the path, plus some other bits of data like
-     the "name" part of the path. Such a path doesn't need
-     signatures, since we don't have to trust anybody's claim that
-     the path is the output of a particular derivation. (In the
-     extensional store model, we have to trust that the *contents*
-     of an output path of a derivation were actually produced by
-     that derivation. In the intensional model, we have to trust
-     that a particular output path was produced by a derivation; the
-     path then implies the contents.)
-
-     Ideally, the content-addressability assertion would just be a
-     Boolean, and the store path would be computed from
-     ‘storePathToName(path)’, ‘narHash’ and ‘references’. However,
-     1) we've accumulated several types of content-addressed paths
-     over the years; and 2) fixed-output derivations support
-     multiple hash algorithms and serialisation methods (flat file
-     vs NAR). Thus, ‘ca’ has one of the following forms:
-
-     * ‘text:sha256:<sha256 hash of file contents>’: For paths
-       computed by makeTextPath() / addTextToStore().
-
-     * ‘fixed:<r?>:<ht>:<h>’: For paths computed by
-       makeFixedOutputPath() / addToStore().
-  */
-  std::string ca;
-
-  bool operator==(const ValidPathInfo& i) const {
-    return path == i.path && narHash == i.narHash && references == i.references;
-  }
-
-  /* Return a fingerprint of the store path to be used in binary
-     cache signatures. It contains the store path, the base-32
-     SHA-256 hash of the NAR serialisation of the path, the size of
-     the NAR, and the sorted references. The size field is strictly
-     speaking superfluous, but might prevent endless/excessive data
-     attacks. */
-  std::string fingerprint() const;
-
-  void sign(const SecretKey& secretKey);
-
-  /* Return true iff the path is verifiably content-addressed. */
-  bool isContentAddressed(const Store& store) const;
-
-  static const size_t maxSigs = std::numeric_limits<size_t>::max();
-
-  /* Return the number of signatures on this .narinfo that were
-     produced by one of the specified keys, or maxSigs if the path
-     is content-addressed. */
-  size_t checkSignatures(const Store& store,
-                         const PublicKeys& publicKeys) const;
-
-  /* Verify a single signature. */
-  bool checkSignature(const PublicKeys& publicKeys,
-                      const std::string& sig) const;
-
-  Strings shortRefs() const;
-
-  virtual ~ValidPathInfo() {}
-};
-
-using ValidPathInfos = std::list<ValidPathInfo>;
-
-enum BuildMode { bmNormal, bmRepair, bmCheck };
-
-// Convert the proto version of a `nix::proto::BuildMode` to its corresponding
-// nix `BuildMode`
-std::optional<BuildMode> BuildModeFrom(nix::proto::BuildMode mode);
-
-// Convert a `nix::BuildMode` to its corresponding proto representation
-nix::proto::BuildMode BuildModeToProto(BuildMode mode);
-
-struct BuildResult {
-  /* Note: don't remove status codes, and only add new status codes
-     at the end of the list, to prevent client/server
-     incompatibilities in the nix-store --serve protocol. */
-  enum Status {
-    Built = 0,
-    Substituted,
-    AlreadyValid,
-    PermanentFailure,
-    InputRejected,
-    OutputRejected,
-    TransientFailure,  // possibly transient
-    CachedFailure,     // no longer used
-    TimedOut,
-    MiscFailure,
-    DependencyFailed,
-    LogLimitExceeded,
-    NotDeterministic,
-  } status = MiscFailure;
-  std::string errorMsg;
-
-  /* How many times this build was performed. */
-  unsigned int timesBuilt = 0;
-
-  /* If timesBuilt > 1, whether some builds did not produce the same
-     result. (Note that 'isNonDeterministic = false' does not mean
-     the build is deterministic, just that we don't have evidence of
-     non-determinism.) */
-  bool isNonDeterministic = false;
-
-  /* The start/stop times of the build (or one of the rounds, if it
-     was repeated). */
-  time_t startTime = 0, stopTime = 0;
-
-  bool success() {
-    return status == Built || status == Substituted || status == AlreadyValid;
-  }
-
-  // Convert the status of this `BuildResult` to its corresponding
-  // `nix::proto::BuildStatus`
-  nix::proto::BuildStatus status_to_proto();
-
-  static std::optional<BuildResult> FromProto(
-      const nix::proto::BuildResult& resp);
-};
-
-class Store : public std::enable_shared_from_this<Store>, public Config {
- public:
-  using Params = std::map<std::string, std::string>;
-
-  const PathSetting storeDir_{this, false, settings.nixStore, "store",
-                              "path to the Nix store"};
-  const Path storeDir = storeDir_;
-
-  const Setting<int> pathInfoCacheSize{
-      this, 65536, "path-info-cache-size",
-      "size of the in-memory store path information cache"};
-
-  const Setting<bool> isTrusted{
-      this, false, "trusted",
-      "whether paths from this store can be used as substitutes even when they "
-      "lack trusted signatures"};
-
- protected:
-  struct State {
-    LRUCache<std::string, std::shared_ptr<ValidPathInfo>> pathInfoCache;
-  };
-
-  Sync<State> state;
-
-  std::shared_ptr<NarInfoDiskCache> diskCache;
-
-  Store(const Params& params);
-
- public:
-  virtual ~Store() {}
-
-  virtual std::string getUri() = 0;
-
-  /* Return true if ‘path’ is in the Nix store (but not the Nix
-     store itself). */
-  bool isInStore(const Path& path) const;
-
-  /* Return true if ‘path’ is a store path, i.e. a direct child of
-     the Nix store. */
-  bool isStorePath(const Path& path) const;
-
-  /* Throw an exception if ‘path’ is not a store path. */
-  void assertStorePath(const Path& path) const;
-
-  /* Chop off the parts after the top-level store name, e.g.,
-     /nix/store/abcd-foo/bar => /nix/store/abcd-foo. */
-  Path toStorePath(const Path& path) const;
-
-  /* Follow symlinks until we end up with a path in the Nix store. */
-  Path followLinksToStore(const Path& path) const;
-
-  /* Same as followLinksToStore(), but apply toStorePath() to the
-     result. */
-  Path followLinksToStorePath(const Path& path) const;
-
-  /* Constructs a unique store path name. */
-  Path makeStorePath(const std::string& type, const Hash& hash,
-                     const std::string& name) const;
-
-  Path makeOutputPath(const std::string& id, const Hash& hash,
-                      const std::string& name) const;
-
-  Path makeFixedOutputPath(bool recursive, const Hash& hash,
-                           const std::string& name) const;
-
-  Path makeTextPath(const std::string& name, const Hash& hash,
-                    const PathSet& references) const;
-
-  /* This is the preparatory part of addToStore(); it computes the
-     store path to which srcPath is to be copied.  Returns the store
-     path and the cryptographic hash of the contents of srcPath. */
-  std::pair<Path, Hash> computeStorePathForPath(
-      const std::string& name, const Path& srcPath, bool recursive = true,
-      HashType hashAlgo = htSHA256,
-      PathFilter& filter = defaultPathFilter) const;
-
-  /* Preparatory part of addTextToStore().
-
-     !!! Computation of the path should take the references given to
-     addTextToStore() into account, otherwise we have a (relatively
-     minor) security hole: a caller can register a source file with
-     bogus references.  If there are too many references, the path may
-     not be garbage collected when it has to be (not really a problem,
-     the caller could create a root anyway), or it may be garbage
-     collected when it shouldn't be (more serious).
-
-     Hashing the references would solve this (bogus references would
-     simply yield a different store path, so other users wouldn't be
-     affected), but it has some backwards compatibility issues (the
-     hashing scheme changes), so I'm not doing that for now. */
-  Path computeStorePathForText(const std::string& name, const std::string& s,
-                               const PathSet& references) const;
-
-  /* Check whether a path is valid. */
-  bool isValidPath(const Path& path);
-
- protected:
-  virtual bool isValidPathUncached(const Path& path);
-
- public:
-  /* Query which of the given paths is valid. Optionally, try to
-     substitute missing paths. */
-  virtual PathSet queryValidPaths(const PathSet& paths,
-                                  SubstituteFlag maybeSubstitute);
-
-  PathSet queryValidPaths(const PathSet& paths) {
-    return queryValidPaths(paths, NoSubstitute);
-  }
-
-  /* Query the set of all valid paths. Note that for some store
-     backends, the name part of store paths may be omitted
-     (i.e. you'll get /nix/store/<hash> rather than
-     /nix/store/<hash>-<name>). Use queryPathInfo() to obtain the
-     full store path. */
-  virtual PathSet queryAllValidPaths() { unsupported("queryAllValidPaths"); }
-
-  /* Query information about a valid path. It is permitted to omit
-     the name part of the store path. */
-  ref<const ValidPathInfo> queryPathInfo(const Path& path);
-
-  /* Asynchronous version of queryPathInfo(). */
-  void queryPathInfo(const Path& path,
-                     Callback<ref<ValidPathInfo>> callback) noexcept;
-
- protected:
-  virtual void queryPathInfoUncached(
-      const Path& path,
-      Callback<std::shared_ptr<ValidPathInfo>> callback) noexcept = 0;
-
- public:
-  /* Queries the set of incoming FS references for a store path.
-     The result is not cleared. */
-  virtual void queryReferrers(const Path& path, PathSet& referrers) {
-    unsupported("queryReferrers");
-  }
-
-  /* Return all currently valid derivations that have `path' as an
-     output.  (Note that the result of `queryDeriver()' is the
-     derivation that was actually used to produce `path', which may
-     not exist anymore.) */
-  virtual PathSet queryValidDerivers(const Path& path) { return {}; };
-
-  /* Query the outputs of the derivation denoted by `path'. */
-  virtual PathSet queryDerivationOutputs(const Path& path) {
-    unsupported("queryDerivationOutputs");
-  }
-
-  /* Query the output names of the derivation denoted by `path'. */
-  virtual StringSet queryDerivationOutputNames(const Path& path) {
-    unsupported("queryDerivationOutputNames");
-  }
-
-  /* Query the full store path given the hash part of a valid store
-     path, or "" if the path doesn't exist. */
-  virtual Path queryPathFromHashPart(const std::string& hashPart) = 0;
-
-  /* Query which of the given paths have substitutes. */
-  virtual PathSet querySubstitutablePaths(const PathSet& paths) { return {}; };
-
-  /* Query substitute info (i.e. references, derivers and download
-     sizes) of a set of paths.  If a path does not have substitute
-     info, it's omitted from the resulting ‘infos’ map. */
-  virtual void querySubstitutablePathInfos(const PathSet& paths,
-                                           SubstitutablePathInfos& infos) {
-    return;
-  };
-
-  virtual bool wantMassQuery() { return false; }
-
-  /* Import a path into the store. */
-  virtual void addToStore(const ValidPathInfo& info, Source& narSource,
-                          RepairFlag repair = NoRepair,
-                          CheckSigsFlag checkSigs = CheckSigs,
-                          std::shared_ptr<FSAccessor> accessor = 0);
-
-  // FIXME: remove
-  virtual void addToStore(const ValidPathInfo& info,
-                          const ref<std::string>& nar,
-                          RepairFlag repair = NoRepair,
-                          CheckSigsFlag checkSigs = CheckSigs,
-                          std::shared_ptr<FSAccessor> accessor = 0);
-
-  /* Copy the contents of a path to the store and register the
-     validity of the resulting path.  The resulting path is returned.
-     The function object `filter' can be used to exclude files (see
-     libutil/archive.hh). If recursive is set to true, the path will be treated
-     as a directory (eg cp -r vs cp) */
-  virtual Path addToStore(const std::string& name, const Path& srcPath,
-                          bool recursive = true, HashType hashAlgo = htSHA256,
-                          PathFilter& filter = defaultPathFilter,
-                          RepairFlag repair = NoRepair) = 0;
-
-  /* Like addToStore, but the contents written to the output path is
-     a regular file containing the given string. */
-  virtual Path addTextToStore(const std::string& name, const std::string& s,
-                              const PathSet& references,
-                              RepairFlag repair = NoRepair) = 0;
-
-  /* Write a NAR dump of a store path. */
-  virtual void narFromPath(const Path& path, Sink& sink) = 0;
-
-  /* For each path, if it's a derivation, build it.  Building a
-     derivation means ensuring that the output paths are valid.  If
-     they are already valid, this is a no-op.  Otherwise, validity
-     can be reached in two ways.  First, if the output paths is
-     substitutable, then build the path that way.  Second, the
-     output paths can be created by running the builder, after
-     recursively building any sub-derivations. For inputs that are
-     not derivations, substitute them. */
-  [[nodiscard]] virtual absl::Status buildPaths(std::ostream& log_sink,
-                                                const PathSet& paths,
-                                                BuildMode build_mode);
-
-  [[nodiscard]] absl::Status buildPaths(std::ostream& log_sink,
-                                        const PathSet& paths) {
-    return buildPaths(log_sink, paths, bmNormal);
-  }
-
-  /* Build a single non-materialized derivation (i.e. not from an
-     on-disk .drv file). Note that ‘drvPath’ is only used for
-     informational purposes. */
-  // TODO(tazjin): Thread std::ostream through here, too.
-  virtual BuildResult buildDerivation(std::ostream& log_sink,
-                                      const Path& drvPath,
-                                      const BasicDerivation& drv,
-                                      BuildMode buildMode) = 0;
-
-  BuildResult buildDerivation(std::ostream& log_sink, const Path& drvPath,
-                              const BasicDerivation& drv) {
-    return buildDerivation(log_sink, drvPath, drv, bmNormal);
-  }
-
-  /* Ensure that a path is valid.  If it is not currently valid, it
-     may be made valid by running a substitute (if defined for the
-     path). */
-  virtual void ensurePath(const Path& path) = 0;
-
-  /* Add a store path as a temporary root of the garbage collector.
-     The root disappears as soon as we exit. */
-  virtual void addTempRoot(const Path& path) { unsupported("addTempRoot"); }
-
-  /* Add an indirect root, which is merely a symlink to `path' from
-     /nix/var/nix/gcroots/auto/<hash of `path'>.  `path' is supposed
-     to be a symlink to a store path.  The garbage collector will
-     automatically remove the indirect root when it finds that
-     `path' has disappeared. */
-  virtual void addIndirectRoot(const Path& path) {
-    unsupported("addIndirectRoot");
-  }
-
-  /* Acquire the global GC lock, then immediately release it.  This
-     function must be called after registering a new permanent root,
-     but before exiting.  Otherwise, it is possible that a running
-     garbage collector doesn't see the new root and deletes the
-     stuff we've just built.  By acquiring the lock briefly, we
-     ensure that either:
-
-     - The collector is already running, and so we block until the
-       collector is finished.  The collector will know about our
-       *temporary* locks, which should include whatever it is we
-       want to register as a permanent lock.
-
-     - The collector isn't running, or it's just started but hasn't
-       acquired the GC lock yet.  In that case we get and release
-       the lock right away, then exit.  The collector scans the
-       permanent root and sees our's.
-
-     In either case the permanent root is seen by the collector. */
-  virtual void syncWithGC(){};
-
-  /* Find the roots of the garbage collector.  Each root is a pair
-     (link, storepath) where `link' is the path of the symlink
-     outside of the Nix store that point to `storePath'. If
-     'censor' is true, privacy-sensitive information about roots
-     found in /proc is censored. */
-  virtual Roots findRoots(bool censor) { unsupported("findRoots"); }
-
-  /* Perform a garbage collection. */
-  virtual void collectGarbage(const GCOptions& options, GCResults& results) {
-    unsupported("collectGarbage");
-  }
-
-  /* Return a string representing information about the path that
-     can be loaded into the database using `nix-store --load-db' or
-     `nix-store --register-validity'. */
-  std::string makeValidityRegistration(const PathSet& paths, bool showDerivers,
-                                       bool showHash);
-
-  /* Write a JSON representation of store path metadata, such as the
-     hash and the references. If ‘includeImpureInfo’ is true,
-     variable elements such as the registration time are
-     included. If ‘showClosureSize’ is true, the closure size of
-     each path is included. */
-  void pathInfoToJSON(JSONPlaceholder& jsonOut, const PathSet& storePaths,
-                      bool includeImpureInfo, bool showClosureSize,
-                      AllowInvalidFlag allowInvalid = DisallowInvalid);
-
-  /* Return the size of the closure of the specified path, that is,
-     the sum of the size of the NAR serialisation of each path in
-     the closure. */
-  std::pair<uint64_t, uint64_t> getClosureSize(const Path& storePath);
-
-  /* Optimise the disk space usage of the Nix store by hard-linking files
-     with the same contents. */
-  virtual void optimiseStore(){};
-
-  /* Check the integrity of the Nix store.  Returns true if errors
-     remain. */
-  virtual bool verifyStore(bool checkContents, RepairFlag repair = NoRepair) {
-    return false;
-  };
-
-  /* Return an object to access files in the Nix store. */
-  virtual ref<FSAccessor> getFSAccessor() { unsupported("getFSAccessor"); }
-
-  /* Add signatures to the specified store path. The signatures are
-     not verified. */
-  virtual void addSignatures(const Path& storePath, const StringSet& sigs) {
-    unsupported("addSignatures");
-  }
-
-  /* Utility functions. */
-
-  /* Read a derivation, after ensuring its existence through
-     ensurePath(). */
-  Derivation derivationFromPath(const Path& drvPath);
-
-  /* Place in `out' the set of all store paths in the file system
-     closure of `storePath'; that is, all paths than can be directly
-     or indirectly reached from it.  `out' is not cleared.  If
-     `flipDirection' is true, the set of paths that can reach
-     `storePath' is returned; that is, the closures under the
-     `referrers' relation instead of the `references' relation is
-     returned. */
-  virtual void computeFSClosure(const PathSet& paths, PathSet& paths_,
-                                bool flipDirection = false,
-                                bool includeOutputs = false,
-                                bool includeDerivers = false);
-
-  void computeFSClosure(const Path& path, PathSet& paths_,
-                        bool flipDirection = false, bool includeOutputs = false,
-                        bool includeDerivers = false);
-
-  /* Given a set of paths that are to be built, return the set of
-     derivations that will be built, and the set of output paths
-     that will be substituted. */
-  virtual void queryMissing(const PathSet& targets, PathSet& willBuild,
-                            PathSet& willSubstitute, PathSet& unknown,
-                            unsigned long long& downloadSize,
-                            unsigned long long& narSize);
-
-  /* Sort a set of paths topologically under the references
-     relation.  If p refers to q, then p precedes q in this list. */
-  Paths topoSortPaths(const PathSet& paths);
-
-  /* Export multiple paths in the format expected by ‘nix-store
-     --import’. */
-  void exportPaths(const Paths& paths, Sink& sink);
-
-  void exportPath(const Path& path, Sink& sink);
-
-  /* Import a sequence of NAR dumps created by exportPaths() into
-     the Nix store. Optionally, the contents of the NARs are
-     preloaded into the specified FS accessor to speed up subsequent
-     access. */
-  Paths importPaths(Source& source, const std::shared_ptr<FSAccessor>& accessor,
-                    CheckSigsFlag checkSigs = CheckSigs);
-
-  struct Stats {
-    std::atomic<uint64_t> narInfoRead{0};
-    std::atomic<uint64_t> narInfoReadAverted{0};
-    std::atomic<uint64_t> narInfoMissing{0};
-    std::atomic<uint64_t> narInfoWrite{0};
-    std::atomic<uint64_t> pathInfoCacheSize{0};
-    std::atomic<uint64_t> narRead{0};
-    std::atomic<uint64_t> narReadBytes{0};
-    std::atomic<uint64_t> narReadCompressedBytes{0};
-    std::atomic<uint64_t> narWrite{0};
-    std::atomic<uint64_t> narWriteAverted{0};
-    std::atomic<uint64_t> narWriteBytes{0};
-    std::atomic<uint64_t> narWriteCompressedBytes{0};
-    std::atomic<uint64_t> narWriteCompressionTimeMs{0};
-  };
-
-  const Stats& getStats();
-
-  /* Return the build log of the specified store path, if available,
-     or null otherwise. */
-  virtual std::shared_ptr<std::string> getBuildLog(const Path& path) {
-    return nullptr;
-  }
-
-  /* Hack to allow long-running processes like hydra-queue-runner to
-     occasionally flush their path info cache. */
-  void clearPathInfoCache() { state.lock()->pathInfoCache.clear(); }
-
-  /* Establish a connection to the store, for store types that have
-     a notion of connection. Otherwise this is a no-op. */
-  virtual void connect(){};
-
-  /* Get the protocol version of this store or it's connection. */
-  virtual unsigned int getProtocol() { return 0; };
-
-  /* Get the priority of the store, used to order substituters. In
-     particular, binary caches can specify a priority field in their
-     "nix-cache-info" file. Lower value means higher priority. */
-  virtual int getPriority() { return 0; }
-
-  virtual Path toRealPath(const Path& storePath) { return storePath; }
-
-  virtual void createUser(const std::string& userName, uid_t userId) {}
-
- protected:
-  Stats stats;
-
-  /* Unsupported methods. */
-  [[noreturn]] void unsupported(const std::string& op) {
-    throw Unsupported("operation '%s' is not supported by store '%s'", op,
-                      getUri());
-  }
-};
-
-class LocalFSStore : public virtual Store {
- public:
-  // FIXME: the (Store*) cast works around a bug in gcc that causes
-  // it to emit the call to the Option constructor. Clang works fine
-  // either way.
-  const PathSetting rootDir{(Store*)this, true, "", "root",
-                            "directory prefixed to all other paths"};
-  const PathSetting stateDir{
-      (Store*)this, false,
-      rootDir != "" ? rootDir + "/nix/var/nix" : settings.nixStateDir, "state",
-      "directory where Nix will store state"};
-  const PathSetting logDir{
-      (Store*)this, false,
-      rootDir != "" ? rootDir + "/nix/var/log/nix" : settings.nixLogDir, "log",
-      "directory where Nix will store state"};
-
-  const static std::string drvsLogDir;
-
-  LocalFSStore(const Params& params);
-
-  void narFromPath(const Path& path, Sink& sink) override;
-  ref<FSAccessor> getFSAccessor() override;
-
-  /* Register a permanent GC root. */
-  Path addPermRoot(const Path& storePath, const Path& gcRoot, bool indirect,
-                   bool allowOutsideRootsDir = false);
-
-  virtual Path getRealStoreDir() { return storeDir; }
-
-  Path toRealPath(const Path& storePath) override {
-    assert(isInStore(storePath));
-    return getRealStoreDir() + "/" +
-           std::string(storePath, storeDir.size() + 1);
-  }
-
-  std::shared_ptr<std::string> getBuildLog(const Path& path) override;
-};
-
-/* Extract the name part of the given store path. */
-std::string storePathToName(const Path& path);
-
-/* Extract the hash part of the given store path. */
-std::string storePathToHash(const Path& path);
-
-/* Check whether ‘name’ is a valid store path name part, i.e. contains
-   only the characters [a-zA-Z0-9\+\-\.\_\?\=] and doesn't start with
-   a dot. */
-void checkStoreName(const std::string& name);
-
-/* Copy a path from one store to another. */
-void copyStorePath(ref<Store> srcStore, const ref<Store>& dstStore,
-                   const Path& storePath, RepairFlag repair = NoRepair,
-                   CheckSigsFlag checkSigs = CheckSigs);
-
-/* Copy store paths from one store to another. The paths may be copied
-   in parallel. They are copied in a topologically sorted order
-   (i.e. if A is a reference of B, then A is copied before B), but
-   the set of store paths is not automatically closed; use
-   copyClosure() for that. */
-void copyPaths(ref<Store> srcStore, ref<Store> dstStore,
-               const PathSet& storePaths, RepairFlag repair = NoRepair,
-               CheckSigsFlag checkSigs = CheckSigs,
-               SubstituteFlag substitute = NoSubstitute);
-
-/* Copy the closure of the specified paths from one store to another. */
-void copyClosure(const ref<Store>& srcStore, const ref<Store>& dstStore,
-                 const PathSet& storePaths, RepairFlag repair = NoRepair,
-                 CheckSigsFlag checkSigs = CheckSigs,
-                 SubstituteFlag substitute = NoSubstitute);
-
-/* Remove the temporary roots file for this process.  Any temporary
-   root becomes garbage after this point unless it has been registered
-   as a (permanent) root. */
-void removeTempRoots();
-
-/* Return a Store object to access the Nix store denoted by
-   ‘uri’ (slight misnomer...). Supported values are:
-
-   * ‘local’: The Nix store in /nix/store and database in
-     /nix/var/nix/db, accessed directly.
-
-   * ‘daemon’: The Nix store accessed via a Unix domain socket
-     connection to nix-daemon.
-
-   * ‘unix://<path>’: The Nix store accessed via a Unix domain socket
-     connection to nix-daemon, with the socket located at <path>.
-
-   * ‘auto’ or ‘’: Equivalent to ‘local’ or ‘daemon’ depending on
-     whether the user has write access to the local Nix
-     store/database.
-
-   * ‘file://<path>’: A binary cache stored in <path>.
-
-   * ‘https://<path>’: A binary cache accessed via HTTP.
-
-   * ‘s3://<path>’: A writable binary cache stored on Amazon's Simple
-     Storage Service.
-
-   * ‘ssh://[user@]<host>’: A remote Nix store accessed by running
-     ‘nix-store --serve’ via SSH.
-
-   You can pass parameters to the store implementation by appending
-   ‘?key=value&key=value&...’ to the URI.
-*/
-ref<Store> openStore(const std::string& uri = settings.storeUri.get(),
-                     const Store::Params& extraParams = Store::Params());
-
-enum StoreType { tDaemon, tLocal, tOther };
-
-StoreType getStoreType(const std::string& uri = settings.storeUri.get(),
-                       const std::string& stateDir = settings.nixStateDir);
-
-/* Return the default substituter stores, defined by the
-   ‘substituters’ option and various legacy options. */
-std::list<ref<Store>> getDefaultSubstituters();
-
-/* Store implementation registration. */
-using OpenStore = std::function<std::shared_ptr<Store>(const std::string&,
-                                                       const Store::Params&)>;
-
-struct RegisterStoreImplementation {
-  using Implementations = std::vector<OpenStore>;
-  static Implementations* implementations;
-
-  RegisterStoreImplementation(OpenStore fun) {
-    if (!implementations) {
-      implementations = new Implementations;
-    }
-    implementations->push_back(fun);
-  }
-};
-
-/* Display a set of paths in human-readable form (i.e., between quotes
-   and separated by commas). */
-std::string showPaths(const PathSet& paths);
-
-ValidPathInfo decodeValidPathInfo(std::istream& str, bool hashGiven = false);
-
-/* Compute the content-addressability assertion (ValidPathInfo::ca)
-   for paths created by makeFixedOutputPath() / addToStore(). */
-std::string makeFixedOutputCA(bool recursive, const Hash& hash);
-
-/* Split URI into protocol+hierarchy part and its parameter set. */
-std::pair<std::string, Store::Params> splitUriAndParams(const std::string& uri);
-
-}  // namespace nix