ethereumjs-monorepo

@ethereumjs/mpt

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@ethereumjs/mpt / WalkController

Class: WalkController

Defined in: packages/mpt/src/util/walkController.ts:14

Interface to control how the trie is being traversed. Schedules node visits via a prioritized task queue and invokes the provided callback for each node.

Used by MerklePatriciaTrie.findPath, MerklePatriciaTrie.walkTrie, etc.

Properties

onNode

readonly onNode: FoundNodeFunction

Defined in: packages/mpt/src/util/walkController.ts:16

The FoundNodeFunction to call when a node is found.

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taskExecutor

readonly taskExecutor: PrioritizedTaskExecutor

Defined in: packages/mpt/src/util/walkController.ts:19

Task executor that prioritizes node visits (shorter paths first).

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trie

readonly trie: MerklePatriciaTrie

Defined in: packages/mpt/src/util/walkController.ts:22

The trie being walked.

Methods

allChildren()

allChildren(node, currentKeyNibbles): void

Defined in: packages/mpt/src/util/walkController.ts:84

Runs all children of a node. Priority of these nodes is the key length of the children. Used when walking an Extension or when exploring all branches of a Branch node.

Parameters

node

MPTNode

Node to get all children of and call onNode on.

currentKeyNibbles

Nibbles = []

The current key (nibbles) which would yield the node when trying to get this node with a get operation. Defaults to [].

Returns

void

void

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onlyBranchIndex()

onlyBranchIndex(node, currentKeyNibbles, childIndex, priority?): void

Defined in: packages/mpt/src/util/walkController.ts:144

Pushes a branch of a certain BranchMPTNode to the event queue. Used by findPath when following a specific key (only one child index is traversed).

Parameters

node

BranchMPTNode

The BranchMPTNode to select a branch on.

currentKeyNibbles

Nibbles = []

The current key which leads to the corresponding node. Defaults to [].

childIndex

number

The child index (0–15) to add to the event queue.

priority?

number

Optional priority of the event. Defaults to the total key length.

Returns

void

void

Throws

If node is not a BranchMPTNode or if the branch at childIndex is empty.

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pushNodeToQueue()

pushNodeToQueue(nodeRef, currentKeyNibbles, priority?): void

Defined in: packages/mpt/src/util/walkController.ts:114

Pushes a node to the queue. If the queue has capacity, the node is executed immediately, otherwise it is queued for later execution.

Parameters

nodeRef

NodeReferenceOrRawMPTNode

A node reference (32-byte keccak hash or raw encoding) to enqueue.

currentKeyNibbles

Nibbles = []

The current key (nibbles) corresponding to this node. Defaults to [].

priority?

number

Optional priority. Defaults to key length.

Returns

void

void

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newWalk()

static newWalk(onNode, trie, rootHash, poolSize?): Promise<void>

Defined in: packages/mpt/src/util/walkController.ts:50

Creates and starts an async walk over a trie from the given root. Resolves when all reachable nodes have been visited and no new tasks were scheduled.

Parameters

onNode

FoundNodeFunction

The FoundNodeFunction to call when a node is found.

trie

MerklePatriciaTrie

The trie to walk on.

rootHash

Uint8Array

The root hash (32-byte keccak) to start walking from.

poolSize?

number

Task execution pool size to prevent OOM errors. Defaults to 500.

Returns

Promise<void>

A Promise that resolves when the walk is finished.