Struct exonum_merkledb::indexes::ValueSetIndex

pub struct ValueSetIndex<T: RawAccess, V> { /* fields omitted */ }

A set of value items.

ValueSetIndex implements a set, storing an element as a value and using its hash as a key. ValueSetIndex requires that elements should implement the BinaryValue trait.

Methods

impl<T, V> ValueSetIndex<T, V> where
    T: RawAccess,
    V: BinaryValue + ObjectHash, 

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

Returns true if the set contains the indicated value.

Examples

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

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

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

pub fn contains_by_hash(&self, hash: &Hash) -> bool

Returns true if the set contains a value with the specified hash.

Examples

use exonum_merkledb::{access::CopyAccessExt, TemporaryDB, Database, ValueSetIndex};
use exonum_crypto;

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

let data = vec![1, 2, 3];
let data_hash = exonum_crypto::hash(&data);
assert!(!index.contains_by_hash(&data_hash));

index.insert(data);
assert!(index.contains_by_hash(&data_hash));

pub fn iter(&self) -> Entries<Hash, V>

Returns an iterator over set elements and their hashes. The elements are ordered as per lexicographic ordering of their hashes (i.e., effectively randomly).

Examples

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

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

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

pub fn hashes(&self) -> Keys<Hash>

Returns an iterator over hashes of set elements in ascending order.

Examples

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

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

for val in index.hashes() {
    println!("{:?}", val);
}

pub fn iter_from(&self, from: &Hash) -> Entries<Hash, V>

Returns an iterator visiting all elements in arbitrary order starting from the specified hash of a value. Elements are yielded together with their hashes.

Examples

use exonum_merkledb::{access::CopyAccessExt, TemporaryDB, Database, ValueSetIndex};
use exonum_crypto::Hash;

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

let hash = Hash::default();

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

pub fn hashes_from(&self, from: &Hash) -> Keys<Hash>

Returns an iterator visiting hashes of all elements in ascending order starting from the specified hash.

Examples

use exonum_merkledb::{access::CopyAccessExt, TemporaryDB, Database, ValueSetIndex};
use exonum_crypto::Hash;

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

let hash = Hash::default();

for val in index.hashes_from(&hash) {
    println!("{:?}", val);
}

impl<T, V> ValueSetIndex<T, V> where
    T: RawAccessMut,
    V: BinaryValue + ObjectHash, 

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

Adds a value to the set.

Examples

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

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

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

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

Removes a value from the set.

Examples

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

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

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

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

pub fn remove_by_hash(&mut self, hash: &Hash)

Removes a value corresponding to the specified hash from the set.

Examples

use exonum_merkledb::{access::CopyAccessExt, TemporaryDB, Database, ValueSetIndex};
use exonum_crypto;

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

let data = vec![1, 2, 3];
let data_hash = exonum_crypto::hash(&data);
index.insert(data);
assert!(index.contains_by_hash(&data_hash));

index.remove_by_hash(&data_hash);
assert!(!index.contains_by_hash(&data_hash));

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, ValueSetIndex};

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

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

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

Trait Implementations

impl<T: Debug + RawAccess, V: Debug> Debug for ValueSetIndex<T, V>

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

Formats the value using the given formatter.

impl<T, V> FromAccess<T> for ValueSetIndex<T::Base, V> where
    T: Access,
    V: BinaryValue + ObjectHash, 

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, V> IndexIterator for ValueSetIndex<T, V> where
    T: RawAccess,
    V: BinaryValue + ObjectHash, 

type Key = Hash

Type encompassing index keys.

type Value = V

Type encompassing index values.

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

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

impl<'a, T, V> IntoIterator for &'a ValueSetIndex<T, V> where
    T: RawAccess,
    V: BinaryValue + ObjectHash, 

type Item = (Hash, V)

The type of the elements being iterated over.

type IntoIter = Entries<'a, Hash, V>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.