1 | var Stream = require('stream').Stream;
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2 | var util = require('util');
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3 |
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4 | module.exports = DelayedStream;
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5 | function DelayedStream() {
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6 | this.source = null;
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7 | this.dataSize = 0;
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8 | this.maxDataSize = 1024 * 1024;
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9 | this.pauseStream = true;
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10 |
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11 | this._maxDataSizeExceeded = false;
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12 | this._released = false;
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13 | this._bufferedEvents = [];
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14 | }
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15 | util.inherits(DelayedStream, Stream);
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16 |
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17 | DelayedStream.create = function(source, options) {
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18 | var delayedStream = new this();
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19 |
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20 | options = options || {};
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21 | for (var option in options) {
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22 | delayedStream[option] = options[option];
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23 | }
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24 |
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25 | delayedStream.source = source;
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26 |
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27 | var realEmit = source.emit;
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28 | source.emit = function() {
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29 | delayedStream._handleEmit(arguments);
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30 | return realEmit.apply(source, arguments);
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31 | };
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32 |
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33 | source.on('error', function() {});
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34 | if (delayedStream.pauseStream) {
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35 | source.pause();
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36 | }
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37 |
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38 | return delayedStream;
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39 | };
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40 |
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41 | Object.defineProperty(DelayedStream.prototype, 'readable', {
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42 | configurable: true,
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43 | enumerable: true,
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44 | get: function() {
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45 | return this.source.readable;
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46 | }
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47 | });
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48 |
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49 | DelayedStream.prototype.setEncoding = function() {
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50 | return this.source.setEncoding.apply(this.source, arguments);
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51 | };
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52 |
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53 | DelayedStream.prototype.resume = function() {
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54 | if (!this._released) {
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55 | this.release();
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56 | }
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57 |
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58 | this.source.resume();
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59 | };
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60 |
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61 | DelayedStream.prototype.pause = function() {
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62 | this.source.pause();
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63 | };
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64 |
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65 | DelayedStream.prototype.release = function() {
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66 | this._released = true;
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67 |
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68 | this._bufferedEvents.forEach(function(args) {
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69 | this.emit.apply(this, args);
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70 | }.bind(this));
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71 | this._bufferedEvents = [];
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72 | };
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73 |
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74 | DelayedStream.prototype.pipe = function() {
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75 | var r = Stream.prototype.pipe.apply(this, arguments);
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76 | this.resume();
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77 | return r;
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78 | };
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79 |
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80 | DelayedStream.prototype._handleEmit = function(args) {
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81 | if (this._released) {
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82 | this.emit.apply(this, args);
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83 | return;
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84 | }
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85 |
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86 | if (args[0] === 'data') {
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87 | this.dataSize += args[1].length;
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88 | this._checkIfMaxDataSizeExceeded();
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89 | }
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90 |
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91 | this._bufferedEvents.push(args);
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92 | };
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93 |
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94 | DelayedStream.prototype._checkIfMaxDataSizeExceeded = function() {
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95 | if (this._maxDataSizeExceeded) {
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96 | return;
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97 | }
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98 |
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99 | if (this.dataSize <= this.maxDataSize) {
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100 | return;
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101 | }
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102 |
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103 | this._maxDataSizeExceeded = true;
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104 | var message =
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105 | 'DelayedStream#maxDataSize of ' + this.maxDataSize + ' bytes exceeded.'
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106 | this.emit('error', new Error(message));
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107 | };
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