nix-super/src/libstore/gc-store.hh

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#pragma once
#include "store-api.hh"
namespace nix {
typedef std::unordered_map<StorePath, std::unordered_set<std::string>> Roots;
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.
*/
typedef enum {
gcReturnLive,
gcReturnDead,
gcDeleteDead,
gcDeleteSpecific,
} GCAction;
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. */
StorePathSet pathsToDelete;
/* Stop after at least `maxFreed' bytes have been freed. */
uint64_t maxFreed{std::numeric_limits<uint64_t>::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. */
uint64_t bytesFreed = 0;
};
struct GcStore : public virtual Store
{
inline static std::string operationName = "Garbage collection";
/* 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;
/* 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) = 0;
/* Perform a garbage collection. */
virtual void collectGarbage(const GCOptions & options, GCResults & results) = 0;
};
}