forked from lix-project/lix
c10c61449f
Also, move a few free-standing functions into StoreAPI and Derivation. Also, introduce a non-nullable smart pointer, ref<T>, which is just a wrapper around std::shared_ptr ensuring that the pointer is never null. (For reference-counted values, this is better than passing a "T&", because the latter doesn't maintain the refcount. Usually, the caller will have a shared_ptr keeping the value alive, but that's not always the case, e.g., when passing a reference to a std::thread via std::bind.)
66 lines
1.8 KiB
C++
66 lines
1.8 KiB
C++
#pragma once
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#include "types.hh"
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#include "pathlocks.hh"
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#include <time.h>
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namespace nix {
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struct Generation
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{
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int number;
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Path path;
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time_t creationTime;
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Generation()
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{
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number = -1;
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}
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operator bool() const
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{
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return number != -1;
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}
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};
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typedef list<Generation> Generations;
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/* Returns the list of currently present generations for the specified
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profile, sorted by generation number. */
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Generations findGenerations(Path profile, int & curGen);
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class StoreAPI;
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Path createGeneration(ref<StoreAPI> store, Path profile, Path outPath);
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void deleteGeneration(const Path & profile, unsigned int gen);
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void deleteGenerations(const Path & profile, const std::set<unsigned int> & gensToDelete, bool dryRun);
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void deleteOldGenerations(const Path & profile, bool dryRun);
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void deleteGenerationsOlderThan(const Path & profile, time_t t, bool dryRun);
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void deleteGenerationsOlderThan(const Path & profile, const string & timeSpec, bool dryRun);
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void switchLink(Path link, Path target);
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/* Ensure exclusive access to a profile. Any command that modifies
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the profile first acquires this lock. */
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void lockProfile(PathLocks & lock, const Path & profile);
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/* Optimistic locking is used by long-running operations like `nix-env
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-i'. Instead of acquiring the exclusive lock for the entire
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duration of the operation, we just perform the operation
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optimistically (without an exclusive lock), and check at the end
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whether the profile changed while we were busy (i.e., the symlink
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target changed). If so, the operation is restarted. Restarting is
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generally cheap, since the build results are still in the Nix
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store. Most of the time, only the user environment has to be
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rebuilt. */
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string optimisticLockProfile(const Path & profile);
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}
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