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#pragma once
///@file
#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;
};
}
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