Abi-generate specific event filters based on its topics

[ArtificialPB]

Module

ABI

📝 Description

Currently, each abi-generated event class has an EventFactory, which provides a filter function that returns a subclass of EventFilterBase. For each Event we know which fields are indexed and what type they are.

We should generate a specific subclass of EventFilterBase for each event, where each subclass contains its topics' type-specific filter methods that encode the specific type (e.g. BigInteger for uint256) into Hash and sets it on the internal LogFilter.

For example, we have the following event:

event Transfer(address indexed from, address indexed to, uint256 value)

Abigen would generate something like this:

class TransferEventFilter(
    provider: Middleware,
    factory: EventFactory<Transfer>,
) : EventFilterBase<Transfer, TransferEventFilter>(provider, factory) {
    override val self: TransferEventFilter
        get() = this

    init {
        filter.topic0(factory.abi.topicId)
    }
    
    fun from(address: Address): TransferEventFilter {
        filter.topic1(address)
        return this
    }

    fun from(vararg addresses: Address): TransferEventFilter {
        filter.topic1(addresses)
        return this
    }

    fun to(address: Address): TransferEventFilter {
        filter.topic2(address)
        return this
    }

    fun to(vararg addresses: Address): TransferEventFilter {
        filter.topic2(addresses)
        return this
    }
}