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Diffstat (limited to 'packages/contract-wrappers/src/utils/filter_utils.ts')
-rw-r--r-- | packages/contract-wrappers/src/utils/filter_utils.ts | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/packages/contract-wrappers/src/utils/filter_utils.ts b/packages/contract-wrappers/src/utils/filter_utils.ts new file mode 100644 index 000000000..c5df7321e --- /dev/null +++ b/packages/contract-wrappers/src/utils/filter_utils.ts @@ -0,0 +1,95 @@ +import { + ConstructorAbi, + ContractAbi, + EventAbi, + FallbackAbi, + FilterObject, + LogEntry, + MethodAbi, +} from '@0xproject/types'; +import * as ethUtil from 'ethereumjs-util'; +import * as jsSHA3 from 'js-sha3'; +import * as _ from 'lodash'; +import * as uuid from 'uuid/v4'; + +import { BlockRange, ContractEvents, IndexedFilterValues } from '../types'; + +const TOPIC_LENGTH = 32; + +export const filterUtils = { + generateUUID(): string { + return uuid(); + }, + getFilter( + address: string, + eventName: ContractEvents, + indexFilterValues: IndexedFilterValues, + abi: ContractAbi, + blockRange?: BlockRange, + ): FilterObject { + const eventAbi = _.find(abi, { name: eventName }) as EventAbi; + const eventSignature = filterUtils.getEventSignatureFromAbiByName(eventAbi, eventName); + const topicForEventSignature = ethUtil.addHexPrefix(jsSHA3.keccak256(eventSignature)); + const topicsForIndexedArgs = filterUtils.getTopicsForIndexedArgs(eventAbi, indexFilterValues); + const topics = [topicForEventSignature, ...topicsForIndexedArgs]; + let filter: FilterObject = { + address, + topics, + }; + if (!_.isUndefined(blockRange)) { + filter = { + ...blockRange, + ...filter, + }; + } + return filter; + }, + getEventSignatureFromAbiByName(eventAbi: EventAbi, eventName: ContractEvents): string { + const types = _.map(eventAbi.inputs, 'type'); + const signature = `${eventAbi.name}(${types.join(',')})`; + return signature; + }, + getTopicsForIndexedArgs(abi: EventAbi, indexFilterValues: IndexedFilterValues): Array<string | null> { + const topics: Array<string | null> = []; + for (const eventInput of abi.inputs) { + if (!eventInput.indexed) { + continue; + } + if (_.isUndefined(indexFilterValues[eventInput.name])) { + // Null is a wildcard topic in a JSON-RPC call + topics.push(null); + } else { + const value = indexFilterValues[eventInput.name] as string; + const buffer = ethUtil.toBuffer(value); + const paddedBuffer = ethUtil.setLengthLeft(buffer, TOPIC_LENGTH); + const topic = ethUtil.bufferToHex(paddedBuffer); + topics.push(topic); + } + } + return topics; + }, + matchesFilter(log: LogEntry, filter: FilterObject): boolean { + if (!_.isUndefined(filter.address) && log.address !== filter.address) { + return false; + } + if (!_.isUndefined(filter.topics)) { + return filterUtils.matchesTopics(log.topics, filter.topics); + } + return true; + }, + matchesTopics(logTopics: string[], filterTopics: Array<string[] | string | null>): boolean { + const matchesTopic = _.zipWith(logTopics, filterTopics, filterUtils.matchesTopic.bind(filterUtils)); + const matchesTopics = _.every(matchesTopic); + return matchesTopics; + }, + matchesTopic(logTopic: string, filterTopic: string[] | string | null): boolean { + if (_.isArray(filterTopic)) { + return _.includes(filterTopic, logTopic); + } + if (_.isString(filterTopic)) { + return filterTopic === logTopic; + } + // null topic is a wildcard + return true; + }, +}; |