MyCrypto/common/libs/contract.js
William O'Beirne bf4171dfbd Transaction confirmation modal (#108)
* Add a little arrow icon.

* Replaced toEther function with toUnit to reduce the number of conversion functions wed need. Add tests for conversion functions.

* First pass at a styled confirm transaction modal.

* More data about data

* Hook up generated transaction with modal

* Fix modal position

* Add from address. Restyle a bit.

* Only show textareas and button if transaction has been generated.

* Remove need for param.

* Copy.

* Use non-relative path.

* Initial crack at transaction token support.

* Fix flow type

* Unit tests for contracts and erc20

* Convert contract class to ethereumjs-abi, caught a bug

* Add decodeArgs for contracts, decodeTransfer for erc20

* Show token value in modal

* Show value from transaction data in confirmation.

* Show address of receiver, not token contract

* Flow type

* Only accept bigs

* Unlog

* Use ethereumjs-abis method ID function

* Get transaction stuff out of state. Leave todo notes.

* Intuit token from transaction to address.

* Move generate transaction out of node and into libs/transaction.

* timeout -> interval

* Promise.reject -> throw

* Get default currency from network.

* Add more unit tests for decoding. Adopt the $ prefix for decoding calls.

* Use signed transaction in confirmation modal.
2017-08-23 08:57:18 +02:00

103 lines
2.5 KiB
JavaScript

// @flow
// TODO support events, constructors, fallbacks, array slots, types
import abi from 'ethereumjs-abi';
// There are too many to enumerate since they're somewhat dynamic, list here
// https://github.com/ethereum/wiki/wiki/Ethereum-Contract-ABI#types
type ABIType = string;
type ABITypedSlot = {
name: string,
type: ABIType
};
type ABIMethod = {
name: string,
type: 'function',
constant: boolean,
inputs: ABITypedSlot[],
outputs: ABITypedSlot[],
// default - false
payable?: boolean
};
export type ABI = ABIMethod[];
export type DecodedCall = {
method: ABIMethod,
// TODO: Type this to be an array of BNs when we switch
args: Array<any>
};
// Contract helper, returns data for given call
export default class Contract {
abi: ABI;
constructor(abi: ABI) {
// TODO: Check ABI, throw if it's malformed
this.abi = abi;
}
getMethodAbi(name: string): ABIMethod {
const method = this.abi.find(x => x.name === name);
if (!method) {
throw new Error('Unknown method');
}
if (method.type !== 'function') {
throw new Error('Not a function');
}
return method;
}
getMethodTypes(method: ABIMethod): string[] {
return method.inputs.map(i => i.type);
}
getMethodSelector(method: ABIMethod): string {
return abi
.methodID(method.name, this.getMethodTypes(method))
.toString('hex');
}
call(name: string, args: any[]): string {
const method = this.getMethodAbi(name);
return (
'0x' + this.getMethodSelector(method) + this.encodeArgs(method, args)
);
}
$call(data: string): DecodedCall {
const method = this.abi.find(
mth => data.indexOf(this.getMethodSelector(mth)) !== -1
);
if (!method) {
throw new Error('Unknown method');
}
return {
method,
args: this.decodeArgs(method, data)
};
}
encodeArgs(method: ABIMethod, args: any[]): string {
if (method.inputs.length !== args.length) {
throw new Error('Invalid number of arguments');
}
const inputTypes = method.inputs.map(input => input.type);
return abi.rawEncode(inputTypes, args).toString('hex');
}
// TODO: Type this return to be an array of BNs when we switch
decodeArgs(method: ABIMethod, argData: string): Array<any> {
// Remove method selector from data, if present
argData = argData.replace(`0x${this.getMethodSelector(method)}`, '');
// Convert argdata to a hex buffer for ethereumjs-abi
const argBuffer = new Buffer(argData, 'hex');
// Decode!
return abi.rawDecode(this.getMethodTypes(method), argBuffer);
}
}