///
import { BaseTrie } from '..';
import { FoundNodeFunction } from '../baseTrie';
import { PrioritizedTaskExecutor } from '../prioritizedTaskExecutor';
import { BranchNode, Nibbles, TrieNode } from '../trieNode';
/**
* WalkController is an interface to control how the trie is being traversed.
*/
export declare class WalkController {
readonly onNode: FoundNodeFunction;
readonly taskExecutor: PrioritizedTaskExecutor;
readonly trie: BaseTrie;
private resolve;
private reject;
/**
* Creates a new WalkController
* @param onNode - The `FoundNodeFunction` to call if a node is found.
* @param trie - The `Trie` to walk on.
* @param poolSize - The size of the task queue.
*/
private constructor();
/**
* Async function to create and start a new walk over a trie.
* @param onNode - The `FoundNodeFunction to call if a node is found.
* @param trie - The trie to walk on.
* @param root - The root key to walk on.
* @param poolSize - Task execution pool size to prevent OOM errors. Defaults to 500.
*/
static newWalk(onNode: FoundNodeFunction, trie: BaseTrie, root: Buffer, poolSize?: number): Promise;
private startWalk;
/**
* Run all children of a node. Priority of these nodes are the key length of the children.
* @param node - Node to get all children of and call onNode on.
* @param key - The current `key` which would yield the `node` when trying to get this node with a `get` operation.
*/
allChildren(node: TrieNode, key?: Nibbles): void;
/**
* Push a node to the queue. If the queue has places left for tasks, the node is executed immediately, otherwise it is queued.
* @param nodeRef - Push a node reference to the event queue. This reference is a 32-byte keccak hash of the value corresponding to the `key`.
* @param key - The current key.
* @param priority - Optional priority, defaults to key length
*/
pushNodeToQueue(nodeRef: Buffer, key?: Nibbles, priority?: number): void;
/**
* Push a branch of a certain BranchNode to the event queue.
* @param node - The node to select a branch on. Should be a BranchNode.
* @param key - The current key which leads to the corresponding node.
* @param childIndex - The child index to add to the event queue.
* @param priority - Optional priority of the event, defaults to the total key length.
*/
onlyBranchIndex(node: BranchNode, key: Nibbles | undefined, childIndex: number, priority?: number): void;
private processNode;
}