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TokenAccountUpdateIterator

Data structure to represent a forest of account updates that is being iterated over, in the context of a token manager contract.

The iteration is done in a depth-first manner.

let forest: AccountUpdateForest = ...;
let tokenIterator = TokenAccountUpdateIterator.create(forest, tokenId);

// process the first 5 account updates in the tree
for (let i = 0; i < 5; i++) {
let { accountUpdate, usesThisToken } = tokenIterator.next();
// ... do something with the account update ...
}

Important: Since this is specifically used by token manager contracts to process their entire subtree of account updates, the iterator skips subtrees that don't inherit token permissions and can therefore definitely not use the token.

So, the assumption is that the consumer of this iterator is only interested in account updates that use the token. We still can't avoid processing some account updates that don't use the token, therefore the iterator returns a boolean usesThisToken alongside each account update.

Constructors

new TokenAccountUpdateIterator()

new TokenAccountUpdateIterator(
forest: MerkleListIterator<AccountUpdateTreeBase>,
mayUseToken: {},
selfToken: Field): TokenAccountUpdateIterator

Parameters

forest: MerkleListIterator\<AccountUpdateTreeBase>

mayUseToken

selfToken: Field

Returns

TokenAccountUpdateIterator

Source

lib/mina/token/forest-iterator.ts:56

Properties

currentLayer

currentLayer: Layer;

Source

lib/mina/token/forest-iterator.ts:52


selfToken

selfToken: Field;

Source

lib/mina/token/forest-iterator.ts:54


unfinishedParentLayers

unfinishedParentLayers: MerkleList<Layer>;

Source

lib/mina/token/forest-iterator.ts:53

Methods

assertFinished()

assertFinished(message?: string): void

Parameters

message?: string

Returns

void

Source

lib/mina/token/forest-iterator.ts:137


next()

next(): {
"accountUpdate": update;
"usesThisToken": Bool;
}

Make a single step along a tree of account updates.

This function is guaranteed to visit each account update in the tree that uses the token exactly once, when called repeatedly.

The method makes a best effort to avoid visiting account updates that are not using the token, and in particular, to avoid returning dummy updates. However, neither can be ruled out. We're returning { update, usesThisToken: Bool } and let the caller handle the irrelevant case where usesThisToken is false.

Returns

{
"accountUpdate": update;
"usesThisToken": Bool;
}
accountUpdate
accountUpdate: AccountUpdate = update;
usesThisToken
usesThisToken: Bool;

Source

lib/mina/token/forest-iterator.ts:85


create()

static create(forest: AccountUpdateForest, selfToken: Field): TokenAccountUpdateIterator

Parameters

forest: AccountUpdateForest

selfToken: Field

Returns

TokenAccountUpdateIterator

Source

lib/mina/token/forest-iterator.ts:66