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author | Fabio Berger <me@fabioberger.com> | 2017-11-13 11:17:18 +0800 |
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committer | Fabio Berger <me@fabioberger.com> | 2017-11-13 11:17:18 +0800 |
commit | c4ee2d73865a1444c079b9e2836b7630a0adf03e (patch) | |
tree | b9c7794e7022fb189675d914f5fe58dcabd67dec /packages/0x.js/src/utils/abi_decoder.ts | |
parent | a74ec0effa818a86233fe64cb0dad2c61bbb4bb6 (diff) | |
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Switch over to Lerna + Yarn Workspaces setup for a mono-repo approach
Diffstat (limited to 'packages/0x.js/src/utils/abi_decoder.ts')
-rw-r--r-- | packages/0x.js/src/utils/abi_decoder.ts | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/packages/0x.js/src/utils/abi_decoder.ts b/packages/0x.js/src/utils/abi_decoder.ts new file mode 100644 index 000000000..840ad9be0 --- /dev/null +++ b/packages/0x.js/src/utils/abi_decoder.ts @@ -0,0 +1,68 @@ +import * as Web3 from 'web3'; +import * as _ from 'lodash'; +import BigNumber from 'bignumber.js'; +import {AbiType, DecodedLogArgs, LogWithDecodedArgs, RawLog, SolidityTypes, ContractEventArgs} from '../types'; +import * as SolidityCoder from 'web3/lib/solidity/coder'; + +export class AbiDecoder { + private savedABIs: Web3.AbiDefinition[] = []; + private methodIds: {[signatureHash: string]: Web3.EventAbi} = {}; + constructor(abiArrays: Web3.AbiDefinition[][]) { + _.map(abiArrays, this.addABI.bind(this)); + } + // This method can only decode logs from the 0x & ERC20 smart contracts + public tryToDecodeLogOrNoop<ArgsType extends ContractEventArgs>( + log: Web3.LogEntry): LogWithDecodedArgs<ArgsType>|RawLog { + const methodId = log.topics[0]; + const event = this.methodIds[methodId]; + if (_.isUndefined(event)) { + return log; + } + const logData = log.data; + const decodedParams: DecodedLogArgs = {}; + let dataIndex = 0; + let topicsIndex = 1; + + const nonIndexedInputs = _.filter(event.inputs, input => !input.indexed); + const dataTypes = _.map(nonIndexedInputs, input => input.type); + const decodedData = SolidityCoder.decodeParams(dataTypes, logData.slice('0x'.length)); + + _.map(event.inputs, (param: Web3.EventParameter) => { + // Indexed parameters are stored in topics. Non-indexed ones in decodedData + let value = param.indexed ? log.topics[topicsIndex++] : decodedData[dataIndex++]; + if (param.type === SolidityTypes.Address) { + value = this.padZeros(new BigNumber(value).toString(16)); + } else if (param.type === SolidityTypes.Uint256 || + param.type === SolidityTypes.Uint8 || + param.type === SolidityTypes.Uint ) { + value = new BigNumber(value); + } + decodedParams[param.name] = value; + }); + + return { + ...log, + event: event.name, + args: decodedParams, + }; + } + private addABI(abiArray: Web3.AbiDefinition[]): void { + _.map(abiArray, (abi: Web3.AbiDefinition) => { + if (abi.type === AbiType.Event) { + const signature = `${abi.name}(${_.map(abi.inputs, input => input.type).join(',')})`; + const signatureHash = new Web3().sha3(signature); + this.methodIds[signatureHash] = abi; + } + }); + this.savedABIs = this.savedABIs.concat(abiArray); + } + private padZeros(address: string) { + let formatted = address; + if (_.startsWith(formatted, '0x')) { + formatted = formatted.slice(2); + } + + formatted = _.padStart(formatted, 40, '0'); + return `0x${formatted}`; + } +} |