forked from lix-project/lix
371 lines
13 KiB
C++
371 lines
13 KiB
C++
#pragma once
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#include "hash.hh"
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#include "serialise.hh"
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#include <string>
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#include <map>
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#include <memory>
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namespace nix {
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typedef std::map<Path, Path> Roots;
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struct GCOptions
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{
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/* Garbage collector operation:
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- `gcReturnLive': return the set of paths reachable from
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(i.e. in the closure of) the roots.
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- `gcReturnDead': return the set of paths not reachable from
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the roots.
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- `gcDeleteDead': actually delete the latter set.
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- `gcDeleteSpecific': delete the paths listed in
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`pathsToDelete', insofar as they are not reachable.
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*/
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typedef enum {
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gcReturnLive,
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gcReturnDead,
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gcDeleteDead,
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gcDeleteSpecific,
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} GCAction;
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GCAction action;
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/* If `ignoreLiveness' is set, then reachability from the roots is
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ignored (dangerous!). However, the paths must still be
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unreferenced *within* the store (i.e., there can be no other
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store paths that depend on them). */
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bool ignoreLiveness;
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/* For `gcDeleteSpecific', the paths to delete. */
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PathSet pathsToDelete;
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/* Stop after at least `maxFreed' bytes have been freed. */
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unsigned long long maxFreed;
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GCOptions();
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};
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struct GCResults
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{
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/* Depending on the action, the GC roots, or the paths that would
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be or have been deleted. */
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PathSet paths;
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/* For `gcReturnDead', `gcDeleteDead' and `gcDeleteSpecific', the
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number of bytes that would be or was freed. */
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unsigned long long bytesFreed;
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GCResults()
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{
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bytesFreed = 0;
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}
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};
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struct SubstitutablePathInfo
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{
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Path deriver;
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PathSet references;
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unsigned long long downloadSize; /* 0 = unknown or inapplicable */
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unsigned long long narSize; /* 0 = unknown */
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};
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typedef std::map<Path, SubstitutablePathInfo> SubstitutablePathInfos;
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struct ValidPathInfo
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{
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Path path;
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Path deriver;
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Hash hash;
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PathSet references;
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time_t registrationTime;
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unsigned long long narSize; // 0 = unknown
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unsigned long long id; // internal use only
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ValidPathInfo() : registrationTime(0), narSize(0) { }
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};
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typedef list<ValidPathInfo> ValidPathInfos;
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enum BuildMode { bmNormal, bmRepair, bmCheck };
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class StoreAPI
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{
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public:
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virtual ~StoreAPI() { }
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/* Check whether a path is valid. */
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virtual bool isValidPath(const Path & path) = 0;
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/* Query which of the given paths is valid. */
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virtual PathSet queryValidPaths(const PathSet & paths) = 0;
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/* Query the set of all valid paths. */
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virtual PathSet queryAllValidPaths() = 0;
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/* Query information about a valid path. */
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virtual ValidPathInfo queryPathInfo(const Path & path) = 0;
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/* Query the hash of a valid path. */
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virtual Hash queryPathHash(const Path & path) = 0;
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/* Query the set of outgoing FS references for a store path. The
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result is not cleared. */
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virtual void queryReferences(const Path & path,
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PathSet & references) = 0;
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/* Queries the set of incoming FS references for a store path.
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The result is not cleared. */
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virtual void queryReferrers(const Path & path,
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PathSet & referrers) = 0;
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/* Query the deriver of a store path. Return the empty string if
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no deriver has been set. */
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virtual Path queryDeriver(const Path & path) = 0;
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/* Return all currently valid derivations that have `path' as an
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output. (Note that the result of `queryDeriver()' is the
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derivation that was actually used to produce `path', which may
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not exist anymore.) */
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virtual PathSet queryValidDerivers(const Path & path) = 0;
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/* Query the outputs of the derivation denoted by `path'. */
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virtual PathSet queryDerivationOutputs(const Path & path) = 0;
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/* Query the output names of the derivation denoted by `path'. */
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virtual StringSet queryDerivationOutputNames(const Path & path) = 0;
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/* Query the full store path given the hash part of a valid store
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path, or "" if the path doesn't exist. */
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virtual Path queryPathFromHashPart(const string & hashPart) = 0;
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/* Query which of the given paths have substitutes. */
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virtual PathSet querySubstitutablePaths(const PathSet & paths) = 0;
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/* Query substitute info (i.e. references, derivers and download
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sizes) of a set of paths. If a path does not have substitute
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info, it's omitted from the resulting ‘infos’ map. */
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virtual void querySubstitutablePathInfos(const PathSet & paths,
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SubstitutablePathInfos & infos) = 0;
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/* Copy the contents of a path to the store and register the
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validity the resulting path. The resulting path is returned.
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The function object `filter' can be used to exclude files (see
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libutil/archive.hh). */
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virtual Path addToStore(const string & name, const Path & srcPath,
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bool recursive = true, HashType hashAlgo = htSHA256,
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PathFilter & filter = defaultPathFilter, bool repair = false) = 0;
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/* Like addToStore, but the contents written to the output path is
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a regular file containing the given string. */
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virtual Path addTextToStore(const string & name, const string & s,
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const PathSet & references, bool repair = false) = 0;
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/* Export a store path, that is, create a NAR dump of the store
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path and append its references and its deriver. Optionally, a
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cryptographic signature (created by OpenSSL) of the preceding
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data is attached. */
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virtual void exportPath(const Path & path, bool sign,
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Sink & sink) = 0;
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/* Import a sequence of NAR dumps created by exportPaths() into
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the Nix store. */
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virtual Paths importPaths(bool requireSignature, Source & source) = 0;
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/* For each path, if it's a derivation, build it. Building a
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derivation means ensuring that the output paths are valid. If
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they are already valid, this is a no-op. Otherwise, validity
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can be reached in two ways. First, if the output paths is
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substitutable, then build the path that way. Second, the
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output paths can be created by running the builder, after
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recursively building any sub-derivations. For inputs that are
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not derivations, substitute them. */
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virtual void buildPaths(const PathSet & paths, BuildMode buildMode = bmNormal) = 0;
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/* Ensure that a path is valid. If it is not currently valid, it
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may be made valid by running a substitute (if defined for the
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path). */
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virtual void ensurePath(const Path & path) = 0;
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/* Add a store path as a temporary root of the garbage collector.
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The root disappears as soon as we exit. */
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virtual void addTempRoot(const Path & path) = 0;
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/* Add an indirect root, which is merely a symlink to `path' from
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/nix/var/nix/gcroots/auto/<hash of `path'>. `path' is supposed
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to be a symlink to a store path. The garbage collector will
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automatically remove the indirect root when it finds that
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`path' has disappeared. */
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virtual void addIndirectRoot(const Path & path) = 0;
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/* Acquire the global GC lock, then immediately release it. This
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function must be called after registering a new permanent root,
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but before exiting. Otherwise, it is possible that a running
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garbage collector doesn't see the new root and deletes the
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stuff we've just built. By acquiring the lock briefly, we
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ensure that either:
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- The collector is already running, and so we block until the
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collector is finished. The collector will know about our
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*temporary* locks, which should include whatever it is we
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want to register as a permanent lock.
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- The collector isn't running, or it's just started but hasn't
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acquired the GC lock yet. In that case we get and release
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the lock right away, then exit. The collector scans the
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permanent root and sees our's.
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In either case the permanent root is seen by the collector. */
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virtual void syncWithGC() = 0;
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/* Find the roots of the garbage collector. Each root is a pair
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(link, storepath) where `link' is the path of the symlink
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outside of the Nix store that point to `storePath'. */
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virtual Roots findRoots() = 0;
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/* Perform a garbage collection. */
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virtual void collectGarbage(const GCOptions & options, GCResults & results) = 0;
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/* Return the set of paths that have failed to build.*/
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virtual PathSet queryFailedPaths() = 0;
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/* Clear the "failed" status of the given paths. The special
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value `*' causes all failed paths to be cleared. */
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virtual void clearFailedPaths(const PathSet & paths) = 0;
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/* Return a string representing information about the path that
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can be loaded into the database using `nix-store --load-db' or
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`nix-store --register-validity'. */
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string makeValidityRegistration(const PathSet & paths,
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bool showDerivers, bool showHash);
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/* Optimise the disk space usage of the Nix store by hard-linking files
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with the same contents. */
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virtual void optimiseStore() = 0;
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};
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/* !!! These should be part of the store API, I guess. */
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/* Throw an exception if `path' is not directly in the Nix store. */
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void assertStorePath(const Path & path);
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bool isInStore(const Path & path);
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bool isStorePath(const Path & path);
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/* Extract the name part of the given store path. */
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string storePathToName(const Path & path);
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void checkStoreName(const string & name);
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/* Chop off the parts after the top-level store name, e.g.,
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/nix/store/abcd-foo/bar => /nix/store/abcd-foo. */
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Path toStorePath(const Path & path);
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/* Follow symlinks until we end up with a path in the Nix store. */
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Path followLinksToStore(const Path & path);
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/* Same as followLinksToStore(), but apply toStorePath() to the
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result. */
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Path followLinksToStorePath(const Path & path);
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/* Constructs a unique store path name. */
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Path makeStorePath(const string & type,
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const Hash & hash, const string & name);
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Path makeOutputPath(const string & id,
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const Hash & hash, const string & name);
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Path makeFixedOutputPath(bool recursive,
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HashType hashAlgo, Hash hash, string name);
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/* This is the preparatory part of addToStore() and addToStoreFixed();
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it computes the store path to which srcPath is to be copied.
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Returns the store path and the cryptographic hash of the
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contents of srcPath. */
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std::pair<Path, Hash> computeStorePathForPath(const Path & srcPath,
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bool recursive = true, HashType hashAlgo = htSHA256,
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PathFilter & filter = defaultPathFilter);
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/* Preparatory part of addTextToStore().
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!!! Computation of the path should take the references given to
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addTextToStore() into account, otherwise we have a (relatively
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minor) security hole: a caller can register a source file with
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bogus references. If there are too many references, the path may
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not be garbage collected when it has to be (not really a problem,
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the caller could create a root anyway), or it may be garbage
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collected when it shouldn't be (more serious).
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Hashing the references would solve this (bogus references would
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simply yield a different store path, so other users wouldn't be
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affected), but it has some backwards compatibility issues (the
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hashing scheme changes), so I'm not doing that for now. */
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Path computeStorePathForText(const string & name, const string & s,
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const PathSet & references);
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/* Remove the temporary roots file for this process. Any temporary
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root becomes garbage after this point unless it has been registered
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as a (permanent) root. */
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void removeTempRoots();
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/* Register a permanent GC root. */
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Path addPermRoot(StoreAPI & store, const Path & storePath,
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const Path & gcRoot, bool indirect, bool allowOutsideRootsDir = false);
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/* Sort a set of paths topologically under the references relation.
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If p refers to q, then p preceeds q in this list. */
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Paths topoSortPaths(StoreAPI & store, const PathSet & paths);
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/* For now, there is a single global store API object, but we'll
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purify that in the future. */
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extern std::shared_ptr<StoreAPI> store;
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/* Factory method: open the Nix database, either through the local or
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remote implementation. */
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std::shared_ptr<StoreAPI> openStore(bool reserveSpace = true);
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/* Display a set of paths in human-readable form (i.e., between quotes
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and separated by commas). */
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string showPaths(const PathSet & paths);
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ValidPathInfo decodeValidPathInfo(std::istream & str,
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bool hashGiven = false);
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/* Export multiple paths in the format expected by ‘nix-store
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--import’. */
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void exportPaths(StoreAPI & store, const Paths & paths,
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bool sign, Sink & sink);
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MakeError(SubstError, Error)
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MakeError(BuildError, Error) /* denotes a permanent build failure */
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}
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