nix-super/src/libstore/profiles.hh
Théophane Hufschmitt fb67c1a1fb Factor out the generation of the profile/channel directory
Make sure that all the code paths use the same one, and that the
backwards-compatibility measures are probably in place when needed
2023-03-23 10:22:42 +01:00

89 lines
2.8 KiB
C++
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

#pragma once
#include "types.hh"
#include "pathlocks.hh"
#include <time.h>
namespace nix {
class StorePath;
typedef uint64_t GenerationNumber;
struct Generation
{
GenerationNumber number;
Path path;
time_t creationTime;
};
typedef std::list<Generation> Generations;
/* Returns the list of currently present generations for the specified
profile, sorted by generation number. Also returns the number of
the current generation. */
std::pair<Generations, std::optional<GenerationNumber>> findGenerations(Path profile);
class LocalFSStore;
Path createGeneration(ref<LocalFSStore> store, Path profile, StorePath outPath);
void deleteGeneration(const Path & profile, GenerationNumber gen);
void deleteGenerations(const Path & profile, const std::set<GenerationNumber> & gensToDelete, bool dryRun);
void deleteGenerationsGreaterThan(const Path & profile, GenerationNumber max, bool dryRun);
void deleteOldGenerations(const Path & profile, bool dryRun);
void deleteGenerationsOlderThan(const Path & profile, time_t t, bool dryRun);
void deleteGenerationsOlderThan(const Path & profile, std::string_view timeSpec, bool dryRun);
void switchLink(Path link, Path target);
/* Roll back a profile to the specified generation, or to the most
recent one older than the current. */
void switchGeneration(
const Path & profile,
std::optional<GenerationNumber> dstGen,
bool dryRun);
/* Ensure exclusive access to a profile. Any command that modifies
the profile first acquires this lock. */
void lockProfile(PathLocks & lock, const Path & profile);
/* Optimistic locking is used by long-running operations like `nix-env
-i'. Instead of acquiring the exclusive lock for the entire
duration of the operation, we just perform the operation
optimistically (without an exclusive lock), and check at the end
whether the profile changed while we were busy (i.e., the symlink
target changed). If so, the operation is restarted. Restarting is
generally cheap, since the build results are still in the Nix
store. Most of the time, only the user environment has to be
rebuilt. */
std::string optimisticLockProfile(const Path & profile);
/* Creates and returns the path to a directory suitable for storing the users
profiles. */
Path profilesDir();
/* Returns the path to the profile directory for root (but doesn't try creating it) */
Path rootProfilesDir();
/* Creates and returns the path to the file used for storing the users's channels */
Path defaultChannelsDir();
/* Returns the path to the channel directory for root (but doesn't try creating it) */
Path rootChannelsDir();
/* Resolve the default profile (~/.nix-profile by default, $XDG_STATE_HOME/
nix/profile if XDG Base Directory Support is enabled), and create if doesn't
exist */
Path getDefaultProfile();
}