Fix ABI encoding/decoding functions

[xianny]

Description

While trying to address #2111, I noticed that the method signatures for getABIDecodedTransactionData and getABIDecodedReturnData looked fishy. The return signature for both methods was for the output type of the Solidity function. getABIDecodedTransactionData should return the input type, and getABIDecodedReturnData should return the output type.

Tests passed because the ABI encoder/decoder was also passed the wrong types.

This PR fixes the decoding issue, and adds doc comments for all three methods. You can see the effect of these changes in abi_gen_dummy.ts (generated file). Resolves #2111

getABIDecodedTransactionData(
    callData: string,
): { input: { foo: BigNumber; bar: string; car: string }; lorem: string; ipsum: string; dolor: string } {
    const self = (this as any) as AbiGenDummyContract;
    const abiEncoder = self._lookupAbiEncoder('complexInputComplexOutput((uint256,bytes,string))');
    // tslint:disable boolean-naming
    const abiDecodedCallData = abiEncoder.strictDecode<{
        input: { foo: BigNumber; bar: string; car: string };
        lorem: string;
        ipsum: string;
        dolor: string;
    }>(callData);
    return abiDecodedCallData;
},
getABIDecodedReturnData(
    returnData: string,
): { input: { foo: BigNumber; bar: string; car: string }; lorem: string; ipsum: string; dolor: string } {
    const self = (this as any) as AbiGenDummyContract;
    const abiEncoder = self._lookupAbiEncoder('complexInputComplexOutput((uint256,bytes,string))');
    // tslint:disable boolean-naming
    const abiDecodedReturnData = abiEncoder.strictDecodeReturnValue<{
        input: { foo: BigNumber; bar: string; car: string };
        lorem: string;
        ipsum: string;
        dolor: string;
    }>(returnData);
    return abiDecodedReturnData;
},

struct ComplexInput {
        uint256 foo;
        bytes bar;
        string car;
    }

/// @dev complex input is dynamic and more difficult to decode than simple input.
struct ComplexOutput {
    ComplexInput input;
    bytes lorem;
    bytes ipsum;
    string dolor;
}

function complexInputComplexOutput(ComplexInput memory complexInput)
        public
        pure
        returns (ComplexOutput memory)
    {
        return ComplexOutput({
            input: complexInput,
            lorem: hex'12345678',
            ipsum: hex'87654321',
            dolor: "amet"
        });
    }

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.

[buildsize]

File name	Previous Size	New Size	Change
init.py	7.04 KB	[deleted]
abi_gen_dummy.ts	141.86 KB	[deleted]
lib_dummy.ts	4.84 KB	[deleted]
test_lib_dummy.ts	11.88 KB	[deleted]
environment.pickle	1.56 MB	1.56 MB	0 bytes (0%)
index.doctree	190.98 KB	190.98 KB	0 bytes (0%)
.buildinfo	230 bytes	230 bytes	0 bytes (0%)
genindex.html	5.6 KB	5.6 KB	0 bytes (0%)
index.html	2.52 KB	2.52 KB	0 bytes (0%)
objects.inv	375 bytes	375 bytes	0 bytes (0%)
py-modindex.html	3.07 KB	3.07 KB	0 bytes (0%)
search.html	2.84 KB	2.84 KB	0 bytes (0%)
searchindex.js	5.82 KB	5.82 KB	0 bytes (0%)
index.rst.txt	415 bytes	415 bytes	0 bytes (0%)
alabaster.css	10.92 KB	10.92 KB	0 bytes (0%)
basic.css	11.89 KB	11.89 KB	0 bytes (0%)
custom.css	42 bytes	42 bytes	0 bytes (0%)
doctools.js	9.05 KB	9.05 KB	0 bytes (0%)
documentation_options.js	303 bytes	303 bytes	0 bytes (0%)
file.png	286 bytes	286 bytes	0 bytes (0%)
jquery-[version].js	273.79 KB	273.79 KB	0 bytes (0%)
jquery.js	86.08 KB	86.08 KB	0 bytes (0%)
language_data.js	10.59 KB	10.59 KB	0 bytes (0%)
minus.png	90 bytes	90 bytes	0 bytes (0%)
plus.png	90 bytes	90 bytes	0 bytes (0%)
pygments.css	4.69 KB	4.69 KB	0 bytes (0%)
searchtools.js	15.61 KB	15.61 KB	0 bytes (0%)
underscore-[version].js	34.34 KB	34.34 KB	0 bytes (0%)
underscore.js	11.86 KB	11.86 KB	0 bytes (0%)
contract_addresses.html	17.89 KB	17.89 KB	0 bytes (0%)
contract_artifacts.html	8.24 KB	8.24 KB	0 bytes (0%)
_bootstrap.html	142.73 KB	142.73 KB	0 bytes (0%)
json_schemas.html	12.43 KB	12.43 KB	0 bytes (0%)
order_utils.html	44.83 KB	44.83 KB	0 bytes (0%)
erc20_token.html	88.14 KB	88.14 KB	0 bytes (0%)
exchange.html	506.16 KB	506.16 KB	0 bytes (0%)
tx_params.html	8.83 KB	8.83 KB	0 bytes (0%)
local_message_signer.html	15.07 KB	15.07 KB	0 bytes (0%)
asset_data_utils.html	22.65 KB	22.65 KB	0 bytes (0%)
default_api.html	118.48 KB	118.48 KB	0 bytes (0%)
asset_proxy_owner.html	341.77 KB	341.77 KB	0 bytes (0%)
coordinator.html	127.47 KB	127.47 KB	0 bytes (0%)
coordinator_registry.html	36.15 KB	36.15 KB	0 bytes (0%)
dutch_auction.html	54.84 KB	54.84 KB	0 bytes (0%)
erc20_proxy.html	105.63 KB	105.63 KB	0 bytes (0%)
erc721_proxy.html	105.72 KB	105.72 KB	0 bytes (0%)
erc721_token.html	141.96 KB	141.96 KB	0 bytes (0%)
eth_balance_checker.html	21.03 KB	21.03 KB	0 bytes (0%)
forwarder.html	107.42 KB	107.42 KB	0 bytes (0%)
i_asset_proxy.html	89.89 KB	89.89 KB	0 bytes (0%)
i_validator.html	26.24 KB	26.24 KB	0 bytes (0%)
i_wallet.html	23.61 KB	23.61 KB	0 bytes (0%)
multi_asset_proxy.html	141.39 KB	141.39 KB	0 bytes (0%)
order_validator.html	115.34 KB	115.34 KB	0 bytes (0%)
weth9.html	129.04 KB	129.04 KB	0 bytes (0%)
zrx_token.html	107.34 KB	107.34 KB	0 bytes (0%)
dev_utils.html	339.53 KB	339.53 KB	0 bytes (0%)

[coveralls]

Coverage remained the same at 77.532% when pulling 35d8065 on fix/ABI-encoding-functions into b3f71af on development.

[hysz]

Lgtm! (~‾▿‾)~