ERC20BridgeSampler: batchCall()

[dorothy-zbornak]

Description

We kept adding wrapper functions upon wrapper functions to ERC20BridgeSampler as our needs evolved while keeping the RPC calls to the bare minimum, which resulted in a bloated mess.

This PR stems tech debt by removing all the wrapper functions, leaving only atomic ones, and introducing a batchCall() function that:

• Allows you to call 1 or more public functions on the sampler contract in a single transaction.
• Takes an array of ABI encoded call data for each function call.
• Returns an array of ABI encoded call results for each function call.
• Can even call batchCall() again to recurse.

The upshot is this allows us to compose function calls off-chain instead of adding higher order wrapper functions to and redeploying the sampler contract. This is going to be relevant to fees/gas accounting because we will probably need to sample pairs and quantities that aren't involved in a swap to establish a baseline. Otherwise, we'd be adding some stupid sounding function like getEthPriceAndFillableAmountsAndSampleMarketSell() to the contract 😫.

DexOrderSampler

The DexOrderSampler class has been rewritten to be a convenient wrapper for neatly performing an arbitrary number of batch operations. So instead of doing this:

const [fillableAmounts, dexQuotes] = await
    sampler.getFillableAmountsAndSampleMarketSellAsync(
        orders,
        sampleAmounts,
        sources,
    );

We now do this:

const [fillableAmounts, dexQuotes] = await sampler.executeAsync(
    DexOrderSampler.ops.getOrderFillableTakerAmounts(orders),
    DexOrderSampler.ops.getSellQuotes(
        sources,
        makerToken,
        takerToken,
        sampleAmounts,
    ),
);

Which is much clearer and scalable, imo.

Testing instructions

Types of changes

Checklist:

• Prefix PR title with [WIP] if necessary.
• Add tests to cover changes as needed.
• Update documentation as needed.
• Add new entries to the relevant CHANGELOG.jsons.

[coveralls]

Coverage decreased (-0.2%) to 79.437% when pulling a36ff9e on feat/batched-sampler into 1b83ebd on development.

[dekz]

Looks good, happy to get away from using the addresses as id's. Seems clear the changes for PLP and other sources. Much easier to add a */WETH sample than having to perform 2 calls simultaneously.

[dekz]

😢

[moodlezoup]

okie dokie to me 👍

[moodlezoup]

nit: you've got const [outputToken, inputToken] = getOrderTokens(nativeOrders[0]); later in this function

[moodlezoup]

why no randomAddress ?

[moodlezoup]

ditto