Struct rsdb::Tree
[−]
[src]
pub struct Tree { /* fields omitted */ }
A flash-sympathetic persistent lock-free B+ tree
Methods
impl Tree
[src]
fn new(config: Config) -> Tree
Load existing or create a new Tree
.
fn config(&self) -> &Config
Returns a ref to the current Config
in use by the system.
fn get(&self, key: &[u8]) -> Option<Vec<u8>>
Retrieve a value from the Tree
if it exists.
fn cas(
&self,
key: Vec<u8>,
old: Option<Vec<u8>>,
new: Option<Vec<u8>>
) -> Result<(), Option<Vec<u8>>>
&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);
fn set(&self, key: Vec<u8>, value: Vec<u8>)
Set a key to a new value.
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);
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);
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);