#ifndef __STOREAPI_H
#define __STOREAPI_H
#include <string>
#include <map>
#include <boost/shared_ptr.hpp>
#include "hash.hh"
#include "serialise.hh"
namespace nix {
typedef std::map<Path, Path> Roots;
struct GCOptions
{
/* Garbage collector operation:
- `gcReturnRoots': find and return the set of roots for the
garbage collector. These are the store paths symlinked to in
the `gcroots' directory.
- `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.
*/
typedef enum {
gcReturnRoots,
gcReturnLive,
gcReturnDead,
gcDeleteDead,
gcDeleteSpecific,
} GCAction;
GCAction action;
/* 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;
/* For `gcDeleteSpecific', the paths to delete. */
PathSet pathsToDelete;
/* Stop after at least `maxFreed' bytes have been freed. */
unsigned long long maxFreed;
/* Stop after the number of hard links to the Nix store directory
has dropped to at least `maxLinks'. */
unsigned int maxLinks;
GCOptions()
{
action = gcDeleteDead;
ignoreLiveness = false;
maxFreed = ULLONG_MAX;
maxLinks = UINT_MAX;
}
};
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;
/* The number of file system blocks that would be or was freed. */
unsigned long long blocksFreed;
GCResults()
{
bytesFreed = 0;
blocksFreed = 0;
}
};
class StoreAPI
{
public:
virtual ~StoreAPI() { }
/* Checks whether a path is valid. */
virtual bool isValidPath(const Path & path) = 0;
/* Query the set of valid paths. */
virtual PathSet queryValidPaths() = 0;
/* Queries the hash of a valid path. */
virtual Hash queryPathHash(const Path & path) = 0;
/* Queries the set of outgoing FS references for a store path.
The result is not cleared. */
virtual void queryReferences(const Path & path,
PathSet & references) = 0;
/* Queries the set of incoming FS references for a store path.
The result is not cleared. */
virtual void queryReferrers(const Path & path,
PathSet & referrers) = 0;
/* Query the deriver of a store path. Return the empty string if
no deriver has been set. */
virtual Path queryDeriver(const Path & path) = 0;
/* Query the set of substitutable paths. */
virtual PathSet querySubstitutablePaths() = 0;
/* More efficient variant if we just want to know if a path has
substitutes. */
virtual bool hasSubstitutes(const Path & path);
/* Copy the contents of a path to the store and register the
validity the resulting path. The resulting path is returned.
If `fixed' is true, then the output of a fixed-output
derivation is pre-loaded into the Nix store. The function
object `filter' can be used to exclude files (see
libutil/archive.hh). */
virtual Path addToStore(const Path & srcPath, bool fixed = false,
bool recursive = false, string hashAlgo = "",
PathFilter & filter = defaultPathFilter) = 0;
/* Like addToStore, but the contents written to the output path is
a regular file containing the given string. */
virtual Path addTextToStore(const string & suffix, const string & s,
const PathSet & references) = 0;
/* Export a store path, that is, create a NAR dump of the store
path and append its references and its deriver. Optionally, a
cryptographic signature (created by OpenSSL) of the preceding
data is attached. */
virtual void exportPath(const Path & path, bool sign,
Sink & sink) = 0;
/* Import a NAR dump created by exportPath() into the Nix
store. */
virtual Path importPath(bool requireSignature, Source & source) = 0;
/* Ensure that the output paths of the derivation 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. */
virtual void buildDerivations(const PathSet & drvPaths) = 0;
/* 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) = 0;
/* 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) = 0;
/* 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() = 0;
/* 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'. */
virtual Roots findRoots() = 0;
/* Perform a garbage collection. */
virtual void collectGarbage(const GCOptions & options, GCResults & results) = 0;
};
/* !!! These should be part of the store API, I guess. */
/* Throw an exception if `path' is not directly in the Nix store. */
void assertStorePath(const Path & path);
bool isInStore(const Path & path);
bool isStorePath(const Path & path);
void checkStoreName(const string & name);
/* 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);
/* Follow symlinks until we end up with a path in the Nix store. */
Path followLinksToStore(const Path & path);
/* Same as followLinksToStore(), but apply toStorePath() to the
result. */
Path followLinksToStorePath(const Path & path);
/* Constructs a unique store path name. */
Path makeStorePath(const string & type,
const Hash & hash, const string & suffix);
Path makeFixedOutputPath(bool recursive,
string hashAlgo, Hash hash, string name);
/* This is the preparatory part of addToStore() and addToStoreFixed();
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 Path & srcPath,
bool fixed = false, bool recursive = false, string hashAlgo = "",
PathFilter & filter = defaultPathFilter);
/* 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 string & suffix, const string & s,
const PathSet & references);
/* 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();
/* Register a permanent GC root. */
Path addPermRoot(const Path & storePath, const Path & gcRoot,
bool indirect, bool allowOutsideRootsDir = false);
/* Sort a set of paths topologically under the references relation.
If p refers to q, then p follows q in this list. */
Paths topoSortPaths(const PathSet & paths);
/* For now, there is a single global store API object, but we'll
purify that in the future. */
extern boost::shared_ptr<StoreAPI> store;
/* Factory method: open the Nix database, either through the local or
remote implementation. */
boost::shared_ptr<StoreAPI> openStore();
/* Display a set of paths in human-readable form (i.e., between quotes
and separated by commas). */
string showPaths(const PathSet & paths);
string makeValidityRegistration(const PathSet & paths,
bool showDerivers, bool showHash);
struct ValidPathInfo
{
Path path;
Path deriver;
Hash hash;
PathSet references;
time_t registrationTime;
ValidPathInfo() : registrationTime(0) { }
};
typedef list<ValidPathInfo> ValidPathInfos;
ValidPathInfo decodeValidPathInfo(std::istream & str,
bool hashGiven = false);
}
#endif /* !__STOREAPI_H */
