lix/src/libstore/profiles.hh
John Ericson 0746951be1
Finish converting existing comments for internal API docs (#8146)
* Finish converting existing comments for internal API docs

99% of this was just reformatting existing comments. Only two exceptions:

- Expanded upon `BuildResult::status` compat note

- Split up file-level `symbol-table.hh` doc comments to get
  per-definition docs

Also fixed a few whitespace goofs, turning leading tabs to spaces and
removing trailing spaces.

Picking up from #8133

* Fix two things from comments

* Use triple-backtick not indent for `dumpPath`

* Convert GNU-style `\`..'` quotes to markdown style in API docs

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2023-04-07 13:55:28 +00:00

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#pragma once
///@file
#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);
/**
* Create and return the path to a directory suitable for storing the users
* profiles.
*/
Path profilesDir();
/**
* Return the path to the profile directory for root (but don't try creating it)
*/
Path rootProfilesDir();
/**
* Create and return the path to the file used for storing the users's channels
*/
Path defaultChannelsDir();
/**
* Return the path to the channel directory for root (but don'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();
}