aboutsummaryrefslogtreecommitdiffstats
path: root/lib/abi.js
blob: a0c862593906f10b810249aa767e56eb114f2587 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
/*
    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];
};

/// 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';
    });
};

/// @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 = {};
    filterFunctions(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 = {};
    filterFunctions(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,
    filterFunctions: filterFunctions,
    filterEvents: filterEvents
};