plugeth/lib/abi.js
2015-01-31 13:54:39 +01:00

243 lines
7.5 KiB
JavaScript

/*
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
*/
if (process.env.NODE_ENV !== 'build') {
var BigNumber = require('bignumber.js'); // jshint ignore:line
}
var web3 = require('./web3');
var utils = require('./utils');
var types = require('./types');
var f = require('./formatters');
BigNumber.config({ ROUNDING_MODE: BigNumber.ROUND_DOWN });
var ETH_PADDING = 32;
/// method signature length in bytes
var ETH_METHOD_SIGNATURE_LENGTH = 4;
/// Filters all function from input abi
/// @returns abi array with filtered objects of type 'function'
var filterFunctions = function (json) {
return json.filter(function (current) {
return current.type === 'function';
});
};
/// Filters all events form input abi
/// @returns abi array with filtered objects of type 'event'
var filterEvents = function (json) {
return json.filter(function (current) {
return current.type === 'event';
});
};
/// This method should be called if we want to check if givent type is an array type
/// @returns true if it is, otherwise false
var arrayType = function (type) {
return type.slice(-2) === '[]';
};
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 f.formatInputInt(value.length);
return "";
};
var inputTypes = types.inputTypes();
/// Formats input params to bytes
/// @param abi contract method
/// @param array of params that will be formatted to bytes
/// @returns bytes representation of input params
var toAbiInput = function (method, params) {
var bytes = "";
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;
};
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;
};
var outputTypes = types.outputTypes();
/// Formats output bytes back to param list
/// @param contract abi method
/// @param bytes representtion of output
/// @returns array of output params
var fromAbiOutput = function (method, output) {
output = output.slice(2);
var result = [];
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 = f.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 (types.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 invulnerable
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
/// TODO: refactor creating the parser, do not double logic from contract
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(method, 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(method, 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,
filterFunctions: filterFunctions,
filterEvents: filterEvents
};