diff options
Diffstat (limited to 'packages/utils/src/abi_encoder/evm_data_types/static_bytes.ts')
-rw-r--r-- | packages/utils/src/abi_encoder/evm_data_types/static_bytes.ts | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/packages/utils/src/abi_encoder/evm_data_types/static_bytes.ts b/packages/utils/src/abi_encoder/evm_data_types/static_bytes.ts new file mode 100644 index 000000000..2e371c505 --- /dev/null +++ b/packages/utils/src/abi_encoder/evm_data_types/static_bytes.ts @@ -0,0 +1,78 @@ +import { DataItem, SolidityTypes } from 'ethereum-types'; +import * as ethUtil from 'ethereumjs-util'; +import * as _ from 'lodash'; + +import { DataTypeFactory } from '../abstract_data_types/interfaces'; +import { AbstractBlobDataType } from '../abstract_data_types/types/blob'; +import { RawCalldata } from '../calldata/raw_calldata'; +import { constants } from '../utils/constants'; + +export class StaticBytesDataType extends AbstractBlobDataType { + private static readonly _SIZE_KNOWN_AT_COMPILE_TIME: boolean = true; + private static readonly _MATCHER = RegExp( + '^(byte|bytes(1|2|3|4|5|6|7|8|9|10|11|12|13|14|15|16|17|18|19|20|21|22|23|24|25|26|27|28|29|30|31|32))$', + ); + private static readonly _DEFAULT_WIDTH = 1; + private readonly _width: number; + + public static matchType(type: string): boolean { + return StaticBytesDataType._MATCHER.test(type); + } + + private static _decodeWidthFromType(type: string): number { + const matches = StaticBytesDataType._MATCHER.exec(type); + const width = + !_.isNull(matches) && matches.length === 3 && !_.isUndefined(matches[2]) + ? parseInt(matches[2], constants.DEC_BASE) + : StaticBytesDataType._DEFAULT_WIDTH; + return width; + } + + public constructor(dataItem: DataItem, dataTypeFactory: DataTypeFactory) { + super(dataItem, dataTypeFactory, StaticBytesDataType._SIZE_KNOWN_AT_COMPILE_TIME); + if (!StaticBytesDataType.matchType(dataItem.type)) { + throw new Error(`Tried to instantiate Static Bytes with bad input: ${dataItem}`); + } + this._width = StaticBytesDataType._decodeWidthFromType(dataItem.type); + } + + public getSignature(): string { + // Note that `byte` reduces to `bytes1` + return `${SolidityTypes.Bytes}${this._width}`; + } + + public encodeValue(value: string | Buffer): Buffer { + // 1/2 Convert value into a buffer and do bounds checking + this._sanityCheckValue(value); + const valueBuf = ethUtil.toBuffer(value); + // 2/2 Store value as hex + const valuePadded = ethUtil.setLengthRight(valueBuf, constants.EVM_WORD_WIDTH_IN_BYTES); + return valuePadded; + } + + public decodeValue(calldata: RawCalldata): string { + const valueBufPadded = calldata.popWord(); + const valueBuf = valueBufPadded.slice(0, this._width); + const value = ethUtil.bufferToHex(valueBuf); + this._sanityCheckValue(value); + return value; + } + + private _sanityCheckValue(value: string | Buffer): void { + if (typeof value === 'string') { + if (!_.startsWith(value, '0x')) { + throw new Error(`Tried to encode non-hex value. Value must inlcude '0x' prefix.`); + } else if (value.length % 2 !== 0) { + throw new Error(`Tried to assign ${value}, which is contains a half-byte. Use full bytes only.`); + } + } + const valueBuf = ethUtil.toBuffer(value); + if (valueBuf.byteLength > this._width) { + throw new Error( + `Tried to assign ${value} (${ + valueBuf.byteLength + } bytes), which exceeds max bytes that can be stored in a ${this.getSignature()}`, + ); + } + } +} |