plugeth/lib/abi.js
2015-01-31 19:07:59 +01:00

211 lines
6.4 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
*/
var web3 = require('./web3');
var utils = require('./utils');
var types = require('./types');
var c = require('./const');
var f = require('./formatters');
var displayTypeError = function (type) {
console.error('parser does not support type: ' + type);
};
/// 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 inputs
/// @param array of params that will be formatted to bytes
/// @returns bytes representation of input params
var formatInput = function (inputs, params) {
var bytes = "";
var padding = c.ETH_PADDING * 2;
/// first we iterate in search for dynamic
inputs.forEach(function (input, index) {
bytes += dynamicTypeBytes(input.type, params[index]);
});
inputs.forEach(function (input, i) {
var typeMatch = false;
for (var j = 0; j < inputTypes.length && !typeMatch; j++) {
typeMatch = inputTypes[j].type(inputs[i].type, params[i]);
}
if (!typeMatch) {
displayTypeError(inputs[i].type);
}
var formatter = inputTypes[j - 1].format;
var toAppend = "";
if (arrayType(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 c.ETH_PADDING * 2;
return 0;
};
var outputTypes = types.outputTypes();
/// Formats output bytes back to param list
/// @param contract abi method outputs
/// @param bytes representtion of output
/// @returns array of output params
var formatOutput = function (outs, output) {
output = output.slice(2);
var result = [];
var padding = c.ETH_PADDING * 2;
var dynamicPartLength = outs.reduce(function (acc, curr) {
return acc + dynamicBytesLength(curr.type);
}, 0);
var dynamicPart = output.slice(0, dynamicPartLength);
output = output.slice(dynamicPartLength);
outs.forEach(function (out, i) {
var typeMatch = false;
for (var j = 0; j < outputTypes.length && !typeMatch; j++) {
typeMatch = outputTypes[j].type(outs[i].type);
}
if (!typeMatch) {
displayTypeError(outs[i].type);
}
var formatter = outputTypes[j - 1].format;
if (arrayType(outs[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')(outs[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;
};
/// @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 = utils.extractDisplayName(method.name);
var typeName = utils.extractTypeName(method.name);
var impl = function () {
var params = Array.prototype.slice.call(arguments);
return formatInput(method.inputs, 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 = utils.extractDisplayName(method.name);
var typeName = utils.extractTypeName(method.name);
var impl = function (output) {
return formatOutput(method.outputs, output);
};
if (parser[displayName] === undefined) {
parser[displayName] = impl;
}
parser[displayName][typeName] = impl;
});
return parser;
};
/// @param function/event name for which we want to get signature
/// @returns signature of function/event with given name
var signatureFromAscii = function (name) {
return web3.sha3(web3.fromAscii(name)).slice(0, 2 + c.ETH_SIGNATURE_LENGTH * 2);
};
var eventSignatureFromAscii = function (name) {
return web3.sha3(web3.fromAscii(name));
};
module.exports = {
inputParser: inputParser,
outputParser: outputParser,
formatInput: formatInput,
formatOutput: formatOutput,
signatureFromAscii: signatureFromAscii,
eventSignatureFromAscii: eventSignatureFromAscii
};