Struct rdms::robt::Snapshot

pub struct Snapshot<K, V> where
    K: Clone + Ord + Serialize,
    V: Clone + Diff + Serialize,  { /* fields omitted */ }

A read only snapshot of BTree built using robt index.

Methods

impl<K, V> Snapshot<K, V> where
    K: Clone + Ord + Serialize,
    V: Clone + Diff + Serialize, 

pub fn open(dir: &str, name: &str) -> Result<Snapshot<K, V>>

Open BTree snapshot from file that can be constructed from dir and name.

impl<K, V> Snapshot<K, V> where
    K: Clone + Ord + Serialize,
    V: Clone + Diff + Serialize, 

pub fn len(&self) -> usize

Return number of entries in the snapshot.

pub fn to_seqno(&self) -> u64

Return the last seqno found in this snapshot.

pub fn to_app_meta(&self) -> Result<Vec<u8>>

Return the application metadata.

pub fn to_stats(&self) -> Result<Stats>

Return Btree statistics.

pub fn to_root(&self) -> Result<u64>

Return the file-position for Btree's root node.

Trait Implementations

impl<K, V> Footprint for Snapshot<K, V> where
    K: Clone + Ord + Serialize,
    V: Clone + Diff + Serialize, 

fn footprint(&self) -> isize

impl<K, V> Index<K, V> for Snapshot<K, V> where
    K: Clone + Ord + Serialize + Footprint,
    V: Clone + Diff + Serialize + Footprint,
    <V as Diff>::D: Serialize, 

type W = Snapshot<K, V>

A writer type, that can ingest key-value pairs, associated with this index.

type R = Snapshot<K, V>

A writer type, that can ingest key-value pairs, associated with this index.

fn make_new(&self) -> Result<Box<Self>>

Make a new empty index of this type, with same configuration.

fn to_reader(&mut self) -> Result<Self::R>

Create a new read handle, for multi-threading.

fn to_writer(&mut self) -> Result<Self::W>

writes not allowed !!

impl<K, V> Reader<K, V> for Snapshot<K, V> where
    K: Clone + Ord + Serialize,
    V: Clone + Diff + Serialize,
    <V as Diff>::D: Clone + Serialize, 

fn get<Q: ?Sized>(&self, key: &Q) -> Result<Entry<K, V>> where
    K: Borrow<Q>,
    Q: Ord, 

Get key from index. Returned entry may not have all its previous versions, if it is costly to fetch from disk.

fn iter(&self) -> Result<IndexIter<K, V>>

Iterate over all entries in this index. Returned entry may not have all its previous versions, if it is costly to fetch from disk.

fn range<'a, R, Q: ?Sized>(&'a self, range: R) -> Result<IndexIter<K, V>> where
    K: Borrow<Q>,
    R: 'a + RangeBounds<Q>,
    Q: 'a + Ord, 

Iterate from lower bound to upper bound. Returned entry may not have all its previous versions, if it is costly to fetch from disk.

fn reverse<'a, R, Q: ?Sized>(&'a self, range: R) -> Result<IndexIter<K, V>> where
    K: Borrow<Q>,
    R: 'a + RangeBounds<Q>,
    Q: 'a + Ord, 

Iterate from upper bound to lower bound. Returned entry may not have all its previous versions, if it is costly to fetch from disk.

fn get_with_versions<Q: ?Sized>(&self, key: &Q) -> Result<Entry<K, V>> where
    K: Borrow<Q>,
    Q: Ord, 

Get key from index. Returned entry shall have all its previous versions, can be a costly call.

fn iter_with_versions(&self) -> Result<IndexIter<K, V>>

Iterate over all entries in this index. Returned entry shall have all its previous versions, can be a costly call.

fn range_with_versions<'a, R, Q: ?Sized>(
    &'a self,
    range: R
) -> Result<IndexIter<K, V>> where
    K: Borrow<Q>,
    R: 'a + RangeBounds<Q>,
    Q: 'a + Ord, 

Iterate from lower bound to upper bound. Returned entry shall have all its previous versions, can be a costly call.

fn reverse_with_versions<'a, R, Q: ?Sized>(
    &'a self,
    range: R
) -> Result<IndexIter<K, V>> where
    K: Borrow<Q>,
    R: 'a + RangeBounds<Q>,
    Q: 'a + Ord, 

Iterate from upper bound to lower bound. Returned entry shall have all its previous versions, can be a costly call.

impl<K, V> Writer<K, V> for Snapshot<K, V> where
    K: Clone + Ord + Serialize + Footprint,
    V: Clone + Diff + Serialize + Footprint, 

fn set(&mut self, _key: K, _value: V) -> Result<Option<Entry<K, V>>>

Set {key, value} in index. Return older entry if present. Return the older entry if present. If operation was invalid or NOOP, returned seqno shall be ZERO.

fn set_cas(&mut self, _: K, _: V, _: u64) -> Result<Option<Entry<K, V>>>

Set {key, value} in index if an older entry exists with the same cas value. To create a fresh entry, pass cas as ZERO. Return the older entry if present. If operation was invalid or NOOP, returned seqno shall be ZERO.

fn delete<Q: ?Sized>(&mut self, _key: &Q) -> Result<Option<Entry<K, V>>> where
    K: Borrow<Q>,
    Q: ToOwned<Owned = K> + Ord, 

Delete key from index. Return the mutation and entry if present. If operation was invalid or NOOP, returned seqno shall be ZERO.