Struct exonum_merkledb::indexes::KeySetIndex

pub struct KeySetIndex<T: RawAccess, K: ?Sized> { /* fields omitted */ }

A set of key items.

KeySetIndex implements a set that stores the elements as keys with empty values. KeySetIndex requires that elements should implement the BinaryKey trait.

Methods

impl<T, K: ?Sized> KeySetIndex<T, K> where
    T: RawAccess,
    K: BinaryKey, 

pub fn contains(&self, item: &K) -> bool

Returns true if the set contains the indicated value.

Examples

use exonum_merkledb::{access::CopyAccessExt, TemporaryDB, Database, KeySetIndex};

let db = TemporaryDB::new();
let fork = db.fork();
let mut index = fork.get_key_set("name");
assert!(!index.contains(&1));

index.insert(&1);
assert!(index.contains(&1));

pub fn iter(&self) -> Keys<K>

Returns an iterator over set elements.

Examples

use exonum_merkledb::{access::CopyAccessExt, TemporaryDB, Database, KeySetIndex};

let db = TemporaryDB::new();
let fork = db.fork();
let index = fork.get_key_set::<_, u8>("name");

for val in index.iter() {
    println!("{}", val);
}

pub fn iter_from(&self, from: &K) -> Keys<K>

Returns an iterator over set elements starting from the specified value.

Examples

use exonum_merkledb::{access::CopyAccessExt, TemporaryDB, Database, KeySetIndex};

let db = TemporaryDB::new();
let fork = db.fork();
let index = fork.get_key_set::<_, u8>("name");

for val in index.iter_from(&2) {
    println!("{}", val);
}

impl<T, K: ?Sized> KeySetIndex<T, K> where
    T: RawAccessMut,
    K: BinaryKey, 

pub fn insert(&mut self, item: &K)

Adds a key to the set.

Examples

use exonum_merkledb::{access::CopyAccessExt, TemporaryDB, Database, KeySetIndex};

let db = TemporaryDB::new();
let fork = db.fork();
let mut index = fork.get_key_set("name");

index.insert(&1);
assert!(index.contains(&1));

pub fn remove(&mut self, item: &K)

Removes a key from the set.

Examples

use exonum_merkledb::{access::CopyAccessExt, TemporaryDB, Database, KeySetIndex};

let db = TemporaryDB::new();
let fork = db.fork();
let mut index = fork.get_key_set("name");

index.insert(&1);
assert!(index.contains(&1));

index.remove(&1);
assert!(!index.contains(&1));

pub fn clear(&mut self)

Clears the set, removing all values.

Notes

Currently, this method is not optimized to delete a large set of data. During the execution of this method, the amount of allocated memory is linearly dependent on the number of elements in the index.

Examples

use exonum_merkledb::{access::CopyAccessExt, TemporaryDB, Database, KeySetIndex};

let db = TemporaryDB::new();
let fork = db.fork();
let mut index = fork.get_key_set("name");

index.insert(&1);
assert!(index.contains(&1));

index.clear();
assert!(!index.contains(&1));

Trait Implementations

impl<T: Debug + RawAccess, K: Debug + ?Sized> Debug for KeySetIndex<T, K>

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.

impl<T, K: ?Sized> FromAccess<T> for KeySetIndex<T::Base, K> where
    T: Access,
    K: BinaryKey, 

fn from_access(access: T, addr: IndexAddress) -> Result<Self, AccessError>

Constructs the object at the given address.

fn from_root(access: T) -> Result<Self, AccessError>

Constructs the object from the root of the access.

impl<T, K: ?Sized> IndexIterator for KeySetIndex<T, K> where
    T: RawAccess,
    K: BinaryKey, 

type Key = K

Type encompassing index keys.

type Value = ()

Type encompassing index values.

fn index_iter(&self, from: Option<&K>) -> Entries<K, ()>

Continues iteration from the specified position. If from is None, starts the iteration from scratch.

impl<'a, T, K: ?Sized> IntoIterator for &'a KeySetIndex<T, K> where
    T: RawAccess,
    K: BinaryKey, 

type Item = K::Owned

The type of the elements being iterated over.

type IntoIter = Keys<'a, K>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.