/*
This file is part of ethereum.js.
ethereum.js is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
ethereum.js is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with ethereum.js. If not, see <http://www.gnu.org/licenses/>.
*/
/** @file abi.js
* @authors:
* Marek Kotewicz <marek@ethdev.com>
* Gav Wood <g@ethdev.com>
* @date 2014
*/
// TODO: is these line is supposed to be here?
if (process.env.NODE_ENV !== 'build') {
var BigNumber = require('bignumber.js'); // jshint ignore:line
}
var web3 = require('./web3'); // jshint ignore:line
BigNumber.config({ ROUNDING_MODE: BigNumber.ROUND_DOWN });
var ETH_PADDING = 32;
/// method signature length in bytes
var ETH_METHOD_SIGNATURE_LENGTH = 4;
/// Finds first index of array element matching pattern
/// @param array
/// @param callback pattern
/// @returns index of element
var findIndex = function (array, callback) {
var end = false;
var i = 0;
for (; i < array.length && !end; i++) {
end = callback(array[i]);
}
return end ? i - 1 : -1;
};
/// @returns a function that is used as a pattern for 'findIndex'
var findMethodIndex = function (json, methodName) {
return findIndex(json, function (method) {
return method.name === methodName;
});
};
/// @returns method with given method name
var getMethodWithName = function (json, methodName) {
var index = findMethodIndex(json, methodName);
if (index === -1) {
console.error('method ' + methodName + ' not found in the abi');
return undefined;
}
return json[index];
};
/// @param string string to be padded
/// @param number of characters that result string should have
/// @param sign, by default 0
/// @returns right aligned string
var padLeft = function (string, chars, sign) {
return new Array(chars - string.length + 1).join(sign ? sign : "0") + string;
};
/// @param expected type prefix (string)
/// @returns function which checks if type has matching prefix. if yes, returns true, otherwise false
var prefixedType = function (prefix) {
return function (type) {
return type.indexOf(prefix) === 0;
};
};
/// @param expected type name (string)
/// @returns function which checks if type is matching expected one. if yes, returns true, otherwise false
var namedType = function (name) {
return function (type) {
return name === type;
};
};
var arrayType = function (type) {
return type.slice(-2) === '[]';
};
/// Formats input value to byte representation of int
/// If value is negative, return it's two's complement
/// If the value is floating point, round it down
/// @returns right-aligned byte representation of int
var formatInputInt = function (value) {
var padding = ETH_PADDING * 2;
if (value instanceof BigNumber || typeof value === 'number') {
if (typeof value === 'number')
value = new BigNumber(value);
value = value.round();
if (value.lessThan(0))
value = new BigNumber("ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", 16).plus(value).plus(1);
value = value.toString(16);
}
else if (value.indexOf('0x') === 0)
value = value.substr(2);
else if (typeof value === 'string')
value = formatInputInt(new BigNumber(value));
else
value = (+value).toString(16);
return padLeft(value, padding);
};
/// Formats input value to byte representation of string
/// @returns left-algined byte representation of string
var formatInputString = function (value) {
return web3.fromAscii(value, ETH_PADDING).substr(2);
};
/// Formats input value to byte representation of bool
/// @returns right-aligned byte representation bool
var formatInputBool = function (value) {
return '000000000000000000000000000000000000000000000000000000000000000' + (value ? '1' : '0');
};
/// Formats input value to byte representation of real
/// Values are multiplied by 2^m and encoded as integers
/// @returns byte representation of real
var formatInputReal = function (value) {
return formatInputInt(new BigNumber(value).times(new BigNumber(2).pow(128)));
};
var dynamicTypeBytes = function (type, value) {
// TODO: decide what to do with array of strings
if (arrayType(type) || type === 'string') // only string itself that is dynamic; stringX is static length.
return formatInputInt(value.length);
return "";
};
/// Setups input formatters for solidity types
/// @returns an array of input formatters
var setupInputTypes = function () {
return [
{ type: prefixedType('uint'), format: formatInputInt },
{ type: prefixedType('int'), format: formatInputInt },
{ type: prefixedType('hash'), format: formatInputInt },
{ type: prefixedType('string'), format: formatInputString },
{ type: prefixedType('real'), format: formatInputReal },
{ type: prefixedType('ureal'), format: formatInputReal },
{ type: namedType('address'), format: formatInputInt },
{ type: namedType('bool'), format: formatInputBool }
];
};
var inputTypes = setupInputTypes();
/// Formats input params to bytes
/// @param contract json abi
/// @param name of the method that we want to use
/// @param array of params that will be formatted to bytes
/// @returns bytes representation of input params
var toAbiInput = function (json, methodName, params) {
var bytes = "";
var method = getMethodWithName(json, methodName);
var padding = ETH_PADDING * 2;
/// first we iterate in search for dynamic
method.inputs.forEach(function (input, index) {
bytes += dynamicTypeBytes(input.type, params[index]);
});
method.inputs.forEach(function (input, i) {
var typeMatch = false;
for (var j = 0; j < inputTypes.length && !typeMatch; j++) {
typeMatch = inputTypes[j].type(method.inputs[i].type, params[i]);
}
if (!typeMatch) {
console.error('input parser does not support type: ' + method.inputs[i].type);
}
var formatter = inputTypes[j - 1].format;
var toAppend = "";
if (arrayType(method.inputs[i].type))
toAppend = params[i].reduce(function (acc, curr) {
return acc + formatter(curr);
}, "");
else
toAppend = formatter(params[i]);
bytes += toAppend;
});
return bytes;
};
/// Check if input value is negative
/// @param value is hex format
/// @returns true if it is negative, otherwise false
var signedIsNegative = function (value) {
return (new BigNumber(value.substr(0, 1), 16).toString(2).substr(0, 1)) === '1';
};
/// Formats input right-aligned input bytes to int
/// @returns right-aligned input bytes formatted to int
var formatOutputInt = function (value) {
value = value || "0";
// check if it's negative number
// it it is, return two's complement
if (signedIsNegative(value)) {
return new BigNumber(value, 16).minus(new BigNumber('ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff', 16)).minus(1);
}
return new BigNumber(value, 16);
};
/// Formats big right-aligned input bytes to uint
/// @returns right-aligned input bytes formatted to uint
var formatOutputUInt = function (value) {
value = value || "0";
return new BigNumber(value, 16);
};
/// @returns input bytes formatted to real
var formatOutputReal = function (value) {
return formatOutputInt(value).dividedBy(new BigNumber(2).pow(128));
};
/// @returns input bytes formatted to ureal
var formatOutputUReal = function (value) {
return formatOutputUInt(value).dividedBy(new BigNumber(2).pow(128));
};
/// @returns right-aligned input bytes formatted to hex
var formatOutputHash = function (value) {
return "0x" + value;
};
/// @returns right-aligned input bytes formatted to bool
var formatOutputBool = function (value) {
return value === '0000000000000000000000000000000000000000000000000000000000000001' ? true : false;
};
/// @returns left-aligned input bytes formatted to ascii string
var formatOutputString = function (value) {
return web3.toAscii(value);
};
/// @returns right-aligned input bytes formatted to address
var formatOutputAddress = function (value) {
return "0x" + value.slice(value.length - 40, value.length);
};
var dynamicBytesLength = function (type) {
if (arrayType(type) || type === 'string') // only string itself that is dynamic; stringX is static length.
return ETH_PADDING * 2;
return 0;
};
/// Setups output formaters for solidity types
/// @returns an array of output formatters
var setupOutputTypes = function () {
return [
{ type: prefixedType('uint'), format: formatOutputUInt },
{ type: prefixedType('int'), format: formatOutputInt },
{ type: prefixedType('hash'), format: formatOutputHash },
{ type: prefixedType('string'), format: formatOutputString },
{ type: prefixedType('real'), format: formatOutputReal },
{ type: prefixedType('ureal'), format: formatOutputUReal },
{ type: namedType('address'), format: formatOutputAddress },
{ type: namedType('bool'), format: formatOutputBool }
];
};
var outputTypes = setupOutputTypes();
/// Formats output bytes back to param list
/// @param contract json abi
/// @param name of the method that we want to use
/// @param bytes representtion of output
/// @returns array of output params
var fromAbiOutput = function (json, methodName, output) {
output = output.slice(2);
var result = [];
var method = getMethodWithName(json, methodName);
var padding = ETH_PADDING * 2;
var dynamicPartLength = method.outputs.reduce(function (acc, curr) {
return acc + dynamicBytesLength(curr.type);
}, 0);
var dynamicPart = output.slice(0, dynamicPartLength);
output = output.slice(dynamicPartLength);
method.outputs.forEach(function (out, i) {
var typeMatch = false;
for (var j = 0; j < outputTypes.length && !typeMatch; j++) {
typeMatch = outputTypes[j].type(method.outputs[i].type);
}
if (!typeMatch) {
console.error('output parser does not support type: ' + method.outputs[i].type);
}
var formatter = outputTypes[j - 1].format;
if (arrayType(method.outputs[i].type)) {
var size = formatOutputUInt(dynamicPart.slice(0, padding));
dynamicPart = dynamicPart.slice(padding);
var array = [];
for (var k = 0; k < size; k++) {
array.push(formatter(output.slice(0, padding)));
output = output.slice(padding);
}
result.push(array);
}
else if (prefixedType('string')(method.outputs[i].type)) {
dynamicPart = dynamicPart.slice(padding);
result.push(formatter(output.slice(0, padding)));
output = output.slice(padding);
} else {
result.push(formatter(output.slice(0, padding)));
output = output.slice(padding);
}
});
return result;
};
/// @returns display name for method eg. multiply(uint256) -> multiply
var methodDisplayName = function (method) {
var length = method.indexOf('(');
return length !== -1 ? method.substr(0, length) : method;
};
/// @returns overloaded part of method's name
var methodTypeName = function (method) {
/// TODO: make it not vulnerable
var length = method.indexOf('(');
return length !== -1 ? method.substr(length + 1, method.length - 1 - (length + 1)) : "";
};
/// @param json abi for contract
/// @returns input parser object for given json abi
var inputParser = function (json) {
var parser = {};
json.forEach(function (method) {
var displayName = methodDisplayName(method.name);
var typeName = methodTypeName(method.name);
var impl = function () {
var params = Array.prototype.slice.call(arguments);
return toAbiInput(json, method.name, params);
};
if (parser[displayName] === undefined) {
parser[displayName] = impl;
}
parser[displayName][typeName] = impl;
});
return parser;
};
/// @param json abi for contract
/// @returns output parser for given json abi
var outputParser = function (json) {
var parser = {};
json.forEach(function (method) {
var displayName = methodDisplayName(method.name);
var typeName = methodTypeName(method.name);
var impl = function (output) {
return fromAbiOutput(json, method.name, output);
};
if (parser[displayName] === undefined) {
parser[displayName] = impl;
}
parser[displayName][typeName] = impl;
});
return parser;
};
/// @param method name for which we want to get method signature
/// @returns (promise) contract method signature for method with given name
var methodSignature = function (name) {
return web3.sha3(web3.fromAscii(name)).slice(0, 2 + ETH_METHOD_SIGNATURE_LENGTH * 2);
};
module.exports = {
inputParser: inputParser,
outputParser: outputParser,
methodSignature: methodSignature,
methodDisplayName: methodDisplayName,
methodTypeName: methodTypeName,
getMethodWithName: getMethodWithName
};
