Struct mtbl::Merger

pub struct Merger {
    pub merge_fn: Box<Box<MergeFn>>,
    // some fields omitted
}

An MTBL reader that opens and reads from several MTBL files, merging their contents.

An MTBL can have only one value for a key, so when the inputs have a key collision (more than one source contains the same key), it uses a MergeFn to combine them.

Fields

merge_fn: Box<Box<MergeFn>>

The function used to combine values for colliding keys.

Methods

impl Merger

fn merge_choose_last_value(_key: &[u8], _val0: &[u8], val1: &[u8]) -> Vec<u8>

A default MTBL merging function that chooses the last (second) value for the colliding key.

fn merge_choose_first_value(_key: &[u8], val0: &[u8], _val1: &[u8]) -> Vec<u8>

A simple MTBL merging function that chooses the first value for the colliding key.

fn new<F>(sources: Vec<Reader>, merge_fn: F) -> Merger where
    F: Fn(&[u8], &[u8], &[u8]) -> Vec<u8> + 'static, 

Create a merger from a collection of other sources. Note that you must provide a merge_fn to combine values for colliding keys.

fn add_source<T: 'static + Read>(&mut self, source: T)

Add an additional source of data to be merged.

Trait Implementations

impl Read for Merger

fn raw_mtbl_source(&self) -> &*const mtbl_source

Get the internal mtbl_source pointer.

fn get<T>(&self, key: T) -> Option<Vec<u8>> where
    Self: Sized,
    T: AsRef<[u8]>, 

Get the value of a key, if it's present.

fn iter(&self) -> Iter

Get an iterator over all keys and values.

fn get_prefix<T>(&self, prefix: T) -> Iter where
    Self: Sized,
    T: AsRef<[u8]>, 

Get an iterator over all keys and values where the key starts with the given prefix.

fn get_range<T, U>(&self, key0: T, key1: U) -> Iter where
    Self: Sized,
    T: AsRef<[u8]>,
    U: AsRef<[u8]>, 

Get an iterator over all keys and values, where the keys are between key0 and key1 (inclusive).

impl<'a> IntoIterator for &'a Merger

type Item = (Vec<u8>, Vec<u8>)

The type of the elements being iterated over.

type IntoIter = Iter<'a>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Iter<'a>

Creates an iterator from a value.

impl Drop for Merger

fn drop(&mut self)

A method called when the value goes out of scope.

impl Send for Merger

Merger is thread-safe.

impl Sync for Merger

Merger is thread-safe.