1 | 'use strict';
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2 |
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3 | var _types = require('../types');
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4 |
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5 |
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6 |
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7 |
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8 |
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9 |
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10 |
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11 | let file = null;
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12 | let setupArgs = [];
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13 | let initialized = false;
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14 |
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15 |
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16 |
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17 |
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18 |
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19 |
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20 |
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21 |
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22 |
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23 |
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24 |
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25 |
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26 |
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27 |
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28 | const messageListener = request => {
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29 | switch (request[0]) {
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30 | case _types.CHILD_MESSAGE_INITIALIZE:
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31 | const init = request;
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32 | file = init[2];
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33 | setupArgs = request[3];
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34 | break;
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35 |
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36 | case _types.CHILD_MESSAGE_CALL:
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37 | const call = request;
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38 | execMethod(call[2], call[3]);
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39 | break;
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40 |
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41 | case _types.CHILD_MESSAGE_END:
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42 | end();
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43 | break;
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44 |
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45 | default:
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46 | throw new TypeError(
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47 | `Unexpected request from parent process: ${request[0]}`
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48 | );
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49 | }
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50 | };
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51 |
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52 | process.on('message', messageListener);
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53 |
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54 | function reportSuccess(result) {
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55 | if (!process || !process.send) {
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56 | throw new Error('Child can only be used on a forked process');
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57 | }
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58 |
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59 | process.send([_types.PARENT_MESSAGE_OK, result]);
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60 | }
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61 |
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62 | function reportClientError(error) {
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63 | return reportError(error, _types.PARENT_MESSAGE_CLIENT_ERROR);
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64 | }
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65 |
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66 | function reportInitializeError(error) {
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67 | return reportError(error, _types.PARENT_MESSAGE_SETUP_ERROR);
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68 | }
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69 |
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70 | function reportError(error, type) {
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71 | if (!process || !process.send) {
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72 | throw new Error('Child can only be used on a forked process');
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73 | }
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74 |
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75 | if (error == null) {
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76 | error = new Error('"null" or "undefined" thrown');
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77 | }
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78 |
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79 | process.send([
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80 | type,
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81 | error.constructor && error.constructor.name,
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82 | error.message,
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83 | error.stack,
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84 | typeof error === 'object' ? {...error} : error
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85 | ]);
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86 | }
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87 |
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88 | function end() {
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89 | const main = require(file);
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90 |
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91 | if (!main.teardown) {
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92 | exitProcess();
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93 | return;
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94 | }
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95 |
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96 | execFunction(main.teardown, main, [], exitProcess, exitProcess);
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97 | }
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98 |
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99 | function exitProcess() {
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100 |
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101 | process.removeListener('message', messageListener);
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102 | }
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103 |
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104 | function execMethod(method, args) {
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105 | const main = require(file);
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106 |
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107 | let fn;
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108 |
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109 | if (method === 'default') {
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110 | fn = main.__esModule ? main['default'] : main;
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111 | } else {
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112 | fn = main[method];
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113 | }
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114 |
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115 | function execHelper() {
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116 | execFunction(fn, main, args, reportSuccess, reportClientError);
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117 | }
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118 |
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119 | if (initialized || !main.setup) {
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120 | execHelper();
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121 | return;
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122 | }
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123 |
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124 | initialized = true;
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125 | execFunction(main.setup, main, setupArgs, execHelper, reportInitializeError);
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126 | }
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127 |
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128 | const isPromise = obj =>
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129 | !!obj &&
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130 | (typeof obj === 'object' || typeof obj === 'function') &&
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131 | typeof obj.then === 'function';
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132 |
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133 | function execFunction(fn, ctx, args, onResult, onError) {
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134 | let result;
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135 |
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136 | try {
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137 | result = fn.apply(ctx, args);
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138 | } catch (err) {
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139 | onError(err);
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140 | return;
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141 | }
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142 |
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143 | if (isPromise(result)) {
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144 | result.then(onResult, onError);
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145 | } else {
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146 | onResult(result);
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147 | }
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148 | }
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