Struct Tree

pub struct Tree { /* private fields */ }

atomic lock-free tree A flash-sympathetic persistent lock-free B+ tree

Implementations

impl Tree

pub fn new(config: Config) -> Tree

Load existing or create a new Tree.

pub fn config(&self) -> &Config

Returns a ref to the current Config in use by the system.

pub fn get(&self, key: &[u8]) -> Option<Vec<u8>>

Retrieve a value from the Tree if it exists.

pub fn cas( &self, key: Vec<u8>, old: Option<Vec<u8>>, new: Option<Vec<u8>>, ) -> Result<(), Option<Vec<u8>>>

Compare and swap. Capable of unique creation, conditional modification, or deletion. If old is None, this will only set the value if it doesn’t exist yet. If new is None, will delete the value if old is correct. If both old and new are Some, will modify the value if old is correct.

Examples

use rsdb::Config;
let t = Config::default().tree();

// unique creation
assert_eq!(t.cas(vec![1], None, Some(vec![1])), Ok(()));
assert_eq!(t.cas(vec![1], None, Some(vec![1])), Err(Some(vec![1])));

// conditional modification
assert_eq!(t.cas(vec![1], Some(vec![1]), Some(vec![2])), Ok(()));
assert_eq!(t.cas(vec![1], Some(vec![1]), Some(vec![2])), Err(Some(vec![2])));

// conditional deletion
assert_eq!(t.cas(vec![1], Some(vec![2]), None), Ok(()));
assert_eq!(t.get(&*vec![1]), None);

pub fn set(&self, key: Vec<u8>, value: Vec<u8>)

Set a key to a new value.

pub fn del(&self, key: &[u8]) -> Option<Vec<u8>>

Delete a value, returning the last result if it existed.

Examples

use rsdb::Config;
let t = Config::default().tree();
t.set(vec![1], vec![1]);
assert_eq!(t.del(&*vec![1]), Some(vec![1]));
assert_eq!(t.del(&*vec![1]), None);

pub fn scan(&self, key: &[u8]) -> TreeIter<'_>

Iterate over tuples of keys and values, starting at the provided key.

Examples

use rsdb::Config;
let t = Config::default().tree();
t.set(vec![1], vec![10]);
t.set(vec![2], vec![20]);
t.set(vec![3], vec![30]);
let mut iter = t.scan(&*vec![2]);
assert_eq!(iter.next(), Some((vec![2], vec![20])));
assert_eq!(iter.next(), Some((vec![3], vec![30])));
assert_eq!(iter.next(), None);

pub fn iter(&self) -> TreeIter<'_>

Iterate over the tuples of keys and values in this tree.

Examples

use rsdb::Config;
let t = Config::default().tree();
t.set(vec![1], vec![10]);
t.set(vec![2], vec![20]);
t.set(vec![3], vec![30]);
let mut iter = t.iter();
assert_eq!(iter.next(), Some((vec![1], vec![10])));
assert_eq!(iter.next(), Some((vec![2], vec![20])));
assert_eq!(iter.next(), Some((vec![3], vec![30])));
assert_eq!(iter.next(), None);

Trait Implementations

impl Debug for Tree

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl<'a> IntoIterator for &'a Tree

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

The type of the elements being iterated over.

type IntoIter = TreeIter<'a>

Which kind of iterator are we turning this into?

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

Creates an iterator from a value.

impl Send for Tree

impl Sync for Tree