63 lines
1.7 KiB
JavaScript
63 lines
1.7 KiB
JavaScript
'use strict';
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var inherits = require('inherits');
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var Provider = require('./provider.js');
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var utils = (function() {
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return {
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defineProperty: require('../utils/properties.js').defineProperty,
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};
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})();
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function FallbackProvider(providers) {
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if (providers.length === 0) { throw new Error('no providers'); }
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var network = {};
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['chainId', 'ensAddress', 'name', 'testnet'].forEach(function(key) {
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for (var i = 1; i < providers.length; i++) {
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if (providers[0][key] !== providers[i][key]) {
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throw new Error('incompatible providers - ' + key + ' mismatch');
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}
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}
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network[key] = providers[0][key];
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});
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if (!(this instanceof FallbackProvider)) { throw new Error('missing new'); }
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Provider.call(this, network);
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providers = providers.slice(0);
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Object.defineProperty(this, 'providers', {
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get: function() {
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return providers.slice(0);
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}
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});
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}
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inherits(FallbackProvider, Provider);
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utils.defineProperty(FallbackProvider.prototype, 'perform', function(method, params) {
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var providers = this.providers;
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return new Promise(function(resolve, reject) {
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var firstError = null;
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function next() {
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if (!providers.length) {
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reject(firstError);
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return;
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}
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var provider = providers.shift();
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provider.perform(method, params).then(function(result) {
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return resolve(result);
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}, function (error) {
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if (!firstError) { firstError = error; }
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next();
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}).catch(function(error) { });
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}
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next();
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});
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});
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module.exports = FallbackProvider;
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