Struct ethcore_util::trie::triedbmut::TrieDBMut [] [src]

pub struct TrieDBMut<'a> {
    pub hash_count: usize,
    // some fields omitted
}

A Trie implementation using a generic HashDB backing database.

Use it as a TrieMut trait object. You can use db() to get the backing database object. Note that changes are not committed to the database until commit is called. Querying the root or dropping the trie will commit automatically.

Example

extern crate ethcore_util as util;

use util::trie::*;
use util::hashdb::*;
use util::memorydb::*;
use util::hash::*;

fn main() {
  let mut memdb = MemoryDB::new();
  let mut root = H256::new();
  let mut t = TrieDBMut::new(&mut memdb, &mut root);
  assert!(t.is_empty());
  assert_eq!(*t.root(), ::util::sha3::SHA3_NULL_RLP);
  t.insert(b"foo", b"bar").unwrap();
  assert!(t.contains(b"foo").unwrap());
  assert_eq!(t.get(b"foo").unwrap().unwrap(), DBValue::from_slice(b"bar"));
  t.remove(b"foo").unwrap();
  assert!(!t.contains(b"foo").unwrap());
}

Fields

The number of hash operations this trie has performed. Note that none are performed until changes are committed.

Methods

impl<'a> TrieDBMut<'a>
[src]

Create a new trie with backing database db and empty root.

Create a new trie with the backing database db and root. Returns an error ifroot` does not exist.

Get the backing database.

Get the backing database mutably.

Commit the in-memory changes to disk, freeing their storage and updating the state root.

Trait Implementations

impl<'a> TrieMut for TrieDBMut<'a>
[src]

Return the root of the trie.

Is the trie empty?

What is the value of the given key in this trie?

Insert a key/value pair into the trie. An empty value is equivalent to removing key from the trie. Returns the old value associated with this key, if it existed. Read more

Remove a key from the trie. Equivalent to making it equal to the empty value. Returns the old value associated with this key, if it existed. Read more

Does the trie contain a given key?

impl<'a> Drop for TrieDBMut<'a>
[src]

A method called when the value goes out of scope. Read more