ethers.js/lib/contract.js
2016-07-15 23:47:35 -04:00

128 lines
4.6 KiB
JavaScript

// "coder" is not MIT... We need to find/make an MIT compatible implementation
var coder = require('../node_modules/web3/lib/solidity/coder.js');
var utils = require('./utils.js');
function defineFrozen(object, name, value) {
var frozen = JSON.stringify(value);
Object.defineProperty(object, name, {
enumerable: true,
get: function() { return JSON.parse(frozen); }
});
}
function getKeys(params, key) {
if (!Array.isArray(params)) { throw new Error('invalid params'); }
var result = [];
for (var i = 0; i < params.length; i++) {
if (typeof(params[i][key]) !== 'string') { throw new Error('invalid abi'); }
// @TODO: Check type are valid?
result.push(params[i][key]);
}
return result;
}
function Contract(abi) {
if (!(this instanceof Contract)) { throw new Error('missing new'); }
//defineProperty(this, 'address', address);
// Wrap this up as JSON so we can return a "copy" and avoid mutation
defineFrozen(this, 'abi', abi);
var methods = [], events = [];
abi.forEach(function(method) {
switch (method.type) {
case 'function':
methods.push(method.name);
func = (function() {
var inputTypes = getKeys(method.inputs, 'type');
var outputTypes = getKeys(method.outputs, 'type');
var func = function() {
var signature = method.name + '(' + getKeys(method.inputs, 'type').join(',') + ')';
var result = {
name: method.name,
signature: signature,
};
var params = Array.prototype.slice.call(arguments, 0);
if (params.length < inputTypes.length) {
throw new Error('missing parameter');
} else if (params.length > inputTypes.length) {
throw new Error('too many parameters');
}
signature = '0x' + utils.sha3(signature).slice(0, 4).toString('hex');
result.data = signature + coder.encodeParams(inputTypes, params);
if (method.constant) {
result.type = 'call';
result.parse = function(data) {
return coder.decodeParams(
outputTypes,
utils.hexOrBuffer(data).toString('hex')
)
};
} else {
result.type = 'transaction';
}
return result;
}
defineFrozen(func, 'inputs', getKeys(method.inputs, 'name'));
defineFrozen(func, 'outputs', getKeys(method.outputs, 'name'));
return func;
})();
break;
case 'event':
events.push(method.name);
func = (function() {
var inputTypes = getKeys(method.inputs, 'type');
var func = function() {
var signature = method.name + '(' + getKeys(method.inputs, 'type').join(',') + ')';
var result = {
inputs: method.inputs,
name: method.name,
type: 'filter',
signature: signature,
topics: ['0x' + utils.sha3(signature).toString('hex')],
};
result.parse = function(data) {
return coder.decodeParams(
inputTypes,
utils.hexOrBuffer(data).toString('hex')
);
};
return result;
}
defineFrozen(func, 'inputs', getKeys(method.inputs, 'name'));
return func;
})();
break;
default:
func = (function() {
return function() {
return {type: 'unknown'}
}
})();
break;
}
utils.defineProperty(this, method.name, func);
}, this);
defineFrozen(this, 'methods', methods);
defineFrozen(this, 'events', events);
}
module.exports = Contract;