Struct exar::Log

pub struct Log {
    // some fields omitted
}

Exar DB's log file abstraction.

It offers helper methods to manage a log file and its index. It also allows to open readers and writers for the log file.

Examples

extern crate exar;

use exar::*;

let log = Log::new("/path/to/logs", "test", 100);

let exists = log.ensure_exists().unwrap();
let writer = log.open_writer().unwrap();
let reader = log.open_reader().unwrap();
let index = log.compute_index().unwrap();
log.remove().unwrap();

Methods

impl Log

fn new(path: &str, name: &str, index_granularity: u64) -> Log

Returns a new Log pointing to the given path/name and using the given index granularity.

fn ensure_exists(&self) -> Result<(), DatabaseError>

Ensure the underlying log file exists and creates it if it does not exist, it returns a DatabaseError if a failure occurs while creating the log file.

fn open_reader(&self) -> Result<BufReader<File>, DatabaseError>

Returns a buffered reader for the underlying log file or a DatabaseError if a failure occurs.

fn open_line_reader(&self) -> Result<IndexedLineReader<BufReader<File>>, DatabaseError>

Returns an indexed line reader for the underlying log file or a DatabaseError if a failure occurs.

fn open_line_reader_with_index(&self, index: LinesIndex) -> Result<IndexedLineReader<BufReader<File>>, DatabaseError>

Returns an indexed line reader for the underlying log file and restores the index using the given LinesIndex or a DatabaseError if a failure occurs.

fn open_writer(&self) -> Result<BufWriter<File>, DatabaseError>

Returns a buffered writer for the underlying log file or a DatabaseError if a failure occurs.

fn remove(&self) -> Result<(), DatabaseError>

Removes the underlying log file and its index or a DatabaseError if a failure occurs.

fn compute_index(&self) -> Result<LinesIndex, DatabaseError>

Computes and returns the LinesIndex for the underlying log file or a DatabaseError if a failure occurs.

fn open_index_reader(&self) -> Result<BufReader<File>, DatabaseError>

Returns a buffered reader for the log index file or a DatabaseError if a failure occurs.

fn open_index_writer(&self) -> Result<BufWriter<File>, DatabaseError>

Returns a buffered writer for the log index file or a DatabaseError if a failure occurs.

fn restore_index(&self) -> Result<LinesIndex, DatabaseError>

Restores and returns the log LinesIndex from the log index file or a DatabaseError if a failure occurs.

If the log index file does not exist it will be computed and persisted.

fn persist_index(&self, index: &LinesIndex) -> Result<(), DatabaseError>

Persists the given LinesIndex to a log index file or returns a DatabaseError if a failure occurs.

fn get_path(&self) -> String

Returns the path to the log file.

fn get_index_path(&self) -> String

Returns the path to the log index file.

fn get_index_granularity(&self) -> u64

Returns the lines index granularity for the log file.

Trait Implementations

impl Eq for Log

impl PartialEq for Log

fn eq(&self, __arg_0: &Log) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, __arg_0: &Log) -> bool

This method tests for !=.

impl Debug for Log

fn fmt(&self, __arg_0: &mut Formatter) -> Result

Formats the value using the given formatter.

impl Clone for Log

fn clone(&self) -> Log

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.