146 lines
		
	
	
		
			4.9 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
			
		
		
	
	
			146 lines
		
	
	
		
			4.9 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
/*
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    This file is part of ethereum.js.
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    ethereum.js is free software: you can redistribute it and/or modify
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    it under the terms of the GNU Lesser General Public License as published by
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    the Free Software Foundation, either version 3 of the License, or
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    (at your option) any later version.
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    ethereum.js is distributed in the hope that it will be useful,
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    but WITHOUT ANY WARRANTY; without even the implied warranty of
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    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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    GNU Lesser General Public License for more details.
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    You should have received a copy of the GNU Lesser General Public License
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    along with ethereum.js.  If not, see <http://www.gnu.org/licenses/>.
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*/
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/** @file contract.js
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 * @authors:
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 *   Marek Kotewicz <marek@ethdev.com>
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 * @date 2014
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 */
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var web3 = require('./web3'); // jshint ignore:line
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var abi = require('./abi');
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/**
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 * This method should be called when we want to call / transact some solidity method from javascript
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 * it returns an object which has same methods available as solidity contract description
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 * usage example: 
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 *
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 * var abi = [{
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 *      name: 'myMethod',
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 *      inputs: [{ name: 'a', type: 'string' }],
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 *      outputs: [{name: 'd', type: 'string' }]
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 * }];  // contract abi
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 *
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 * var myContract = web3.eth.contract('0x0123123121', abi); // creation of contract object
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 *
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 * myContract.myMethod('this is test string param for call'); // myMethod call (implicit, default)
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 * myContract.call().myMethod('this is test string param for call'); // myMethod call (explicit)
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 * myContract.transact().myMethod('this is test string param for transact'); // myMethod transact
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 *
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 * @param address - address of the contract, which should be called
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 * @param desc - abi json description of the contract, which is being created
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 * @returns contract object
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 */
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var contract = function (address, desc) {
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    desc.forEach(function (method) {
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        // workaround for invalid assumption that method.name is the full anonymous prototype of the method.
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        // it's not. it's just the name. the rest of the code assumes it's actually the anonymous
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        // prototype, so we make it so as a workaround.
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        if (method.name.indexOf('(') === -1) {
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            var displayName = method.name;
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            var typeName = method.inputs.map(function(i){return i.type; }).join();
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            method.name = displayName + '(' + typeName + ')';
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        }
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    });
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    var inputParser = abi.inputParser(desc);
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    var outputParser = abi.outputParser(desc);
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    var result = {};
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    result.call = function (options) {
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        result._isTransact = false;
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        result._options = options;
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        return result;
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    };
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    result.transact = function (options) {
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        result._isTransact = true;
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        result._options = options;
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        return result;
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    };
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    result._options = {};
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    ['gas', 'gasPrice', 'value', 'from'].forEach(function(p) {
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        result[p] = function (v) {
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            result._options[p] = v;
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            return result;
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        };
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    });
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    desc.forEach(function (method) {
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        var displayName = abi.methodDisplayName(method.name);
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        var typeName = abi.methodTypeName(method.name);
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        var impl = function () {
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            var params = Array.prototype.slice.call(arguments);
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            var signature = abi.methodSignature(method.name);
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            var parsed = inputParser[displayName][typeName].apply(null, params);
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            var options = result._options || {};
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            options.to = address;
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            options.data = signature + parsed;
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            var isTransact = result._isTransact === true || (result._isTransact !== false && !method.constant);
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            var collapse = options.collapse !== false;
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            // reset
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            result._options = {};
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            result._isTransact = null;
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            if (isTransact) {
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                // it's used byt natspec.js
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                // TODO: figure out better way to solve this
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                web3._currentContractAbi = desc;
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                web3._currentContractAddress = address;
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                web3._currentContractMethodName = method.name;
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                web3._currentContractMethodParams = params;
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                // transactions do not have any output, cause we do not know, when they will be processed
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                web3.eth.transact(options);
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                return;
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            }
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            var output = web3.eth.call(options);
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            var ret = outputParser[displayName][typeName](output);
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            if (collapse)
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            {
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                if (ret.length === 1)
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                    ret = ret[0];
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                else if (ret.length === 0)
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                    ret = null;
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            }
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            return ret;
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        };
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        if (result[displayName] === undefined) {
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            result[displayName] = impl;
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        }
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        result[displayName][typeName] = impl;
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    });
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    return result;
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};
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module.exports = contract;
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