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eb233e728f
unreachable paths that haven't been used for N hours. For instance, `nix-collect-garbage --min-age 168' only deletes paths that haven't been accessed in the last week. This is useful for instance in the build farm where many derivations can be shared between consecutive builds, and we wouldn't want a garbage collect to throw them all away. We could of course register them as roots, but then we'd to unregister them at some point, which would be a pain to manage. The `--min-age' flag gives us a sort of MRU caching scheme. BUG: this really shouldn't be in gc.cc since that violates mechanism/policy separation.
27 lines
1.1 KiB
C++
27 lines
1.1 KiB
C++
#ifndef __GC_H
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#define __GC_H
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#include "storeexpr.hh"
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/* Determine the set of "live" store paths, given a set of root store
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expressions. The live store paths are those that are reachable
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from the roots. The roots are reachable by definition. Any path
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mentioned in a reachable store expression is also reachable. If a
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derivation store expression is reachable, then its successor (if it
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exists) if also reachable. It is not an error for store
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expressions not to exist (since this can happen on derivation store
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expressions, for instance, due to the substitute mechanism), but
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successor links are followed even for non-existant derivations. */
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PathSet findLivePaths(const Paths & roots);
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/* Given a set of "live" store paths, determine the set of "dead"
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store paths (which are simply all store paths that are not in the
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live set). The value `minAge' specifies the minimum age in seconds
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for an unreachable file to be considered dead (0 meaning that any
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unreachable file is dead). */
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PathSet findDeadPaths(const PathSet & live, time_t minAge);
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#endif /* !__GC_H */
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