Enum lsm_tree::Entry

pub enum Entry {
    Vacant(VacantEntry),
    Occupied(OccupiedEntry),
}

Represents a single entry in the tree, which may or may not exist.

Variants

Vacant(VacantEntry)

Represents a missing entry in the tree

Occupied(OccupiedEntry)

Represents an existing entry in the tree

Implementations

impl Entry

pub fn key(&self) -> Arc<[u8]>

Returns a reference to this entry’s key

Examples

use lsm_tree::{Config, Tree};

let tree = Tree::open(Config::new(folder))?;

let entry = tree.entry("a")?;
assert_eq!("a".as_bytes(), &*entry.key());

pub fn and_update<V: AsRef<[u8]>, F: FnOnce(&Arc<[u8]>) -> V>( self, f: F ) -> Result<Self>

Updates the value if it exists before any potential inserts.

Examples

use lsm_tree::{Config, Tree};

let tree = Tree::open(Config::new(folder))?;

let value = tree.entry("a")?.or_insert("abc")?;
assert_eq!("abc".as_bytes(), &*value);

let value = tree.entry("a")?.and_update(|_| "def")?.or_insert("abc")?;
assert_eq!("def".as_bytes(), &*value);

Errors

Will return Err if an IO error occurs.

pub fn or_insert<V: AsRef<[u8]>>(&self, value: V) -> Result<Arc<[u8]>>

Ensures a value is in the entry by inserting the default if empty, and returns that value.

Examples

use lsm_tree::{Config, Tree};

let tree = Tree::open(Config::new(folder))?;

let value = tree.entry("a")?.or_insert("abc")?;
assert_eq!("abc".as_bytes(), &*value);

Errors

Will return Err if an IO error occurs.

pub fn or_insert_with<V: AsRef<[u8]>, F: FnOnce() -> V>( &self, f: F ) -> Result<Arc<[u8]>>

Ensures a value is in the entry by inserting the result of the default function if empty, and returns that value.

Examples

use lsm_tree::{Config, Tree};

let tree = Tree::open(Config::new(folder))?;

let value = tree.entry("a")?.or_insert_with(|| "abc")?;
assert_eq!("abc".as_bytes(), &*value);

Errors

Will return Err if an IO error occurs.

pub fn or_insert_with_key<V: AsRef<[u8]>, F: FnOnce(&Arc<[u8]>) -> V>( &self, f: F ) -> Result<Arc<[u8]>>

Ensures a value is in the entry by inserting the result of the default function if empty, and returns that value.

Examples

use lsm_tree::{Config, Tree};

let tree = Tree::open(Config::new(folder))?;

let value = tree.entry("a")?.or_insert_with_key(|k| k.clone())?;
assert_eq!("a".as_bytes(), &*value);

Errors

Will return Err if an IO error occurs.