142 lines
2.9 KiB
JavaScript
142 lines
2.9 KiB
JavaScript
/*
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* buffered-stream.js: A simple(r) Stream which is partially buffered into memory.
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*
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* (C) 2010, Mikeal Rogers
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*
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* Adapted for Flatiron
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* (C) 2011, Charlie Robbins & the Contributors
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* MIT LICENSE
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*
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*/
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var events = require('events'),
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fs = require('fs'),
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stream = require('stream'),
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util = require('util');
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//
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// ### function BufferedStream (limit)
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// #### @limit {number} **Optional** Size of the buffer to limit
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// Constructor function for the BufferedStream object responsible for
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// maintaining a stream interface which can also persist to memory
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// temporarily.
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//
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var BufferedStream = module.exports = function (limit) {
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events.EventEmitter.call(this);
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if (typeof limit === 'undefined') {
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limit = Infinity;
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}
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this.limit = limit;
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this.size = 0;
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this.chunks = [];
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this.writable = true;
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this.readable = true;
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this._buffer = true;
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};
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util.inherits(BufferedStream, stream.Stream);
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Object.defineProperty(BufferedStream.prototype, 'buffer', {
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get: function () {
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return this._buffer;
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},
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set: function (value) {
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if (!value && this.chunks) {
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var self = this;
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this.chunks.forEach(function (c) { self.emit('data', c) });
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if (this.ended) this.emit('end');
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this.size = 0;
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delete this.chunks;
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}
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this._buffer = value;
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}
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});
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BufferedStream.prototype.pipe = function () {
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var self = this,
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dest;
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if (self.resume) {
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self.resume();
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}
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dest = stream.Stream.prototype.pipe.apply(self, arguments);
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//
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// just incase you are piping to two streams, do not emit data twice.
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// note: you can pipe twice, but you need to pipe both streams in the same tick.
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// (this is normal for streams)
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//
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if (this.piped) {
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return dest;
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}
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process.nextTick(function () {
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if (self.chunks) {
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self.chunks.forEach(function (c) { self.emit('data', c) });
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self.size = 0;
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delete self.chunks;
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}
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if (!self.readable) {
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if (self.ended) {
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self.emit('end');
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}
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else if (self.closed) {
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self.emit('close');
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}
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}
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});
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this.piped = true;
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return dest;
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};
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BufferedStream.prototype.write = function (chunk) {
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if (!this.chunks || this.piped) {
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this.emit('data', chunk);
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return;
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}
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this.chunks.push(chunk);
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this.size += chunk.length;
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if (this.limit < this.size) {
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this.pause();
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}
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};
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BufferedStream.prototype.end = function () {
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this.readable = false;
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this.ended = true;
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this.emit('end');
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};
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BufferedStream.prototype.destroy = function () {
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this.readable = false;
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this.writable = false;
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delete this.chunks;
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};
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BufferedStream.prototype.close = function () {
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this.readable = false;
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this.closed = true;
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};
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if (!stream.Stream.prototype.pause) {
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BufferedStream.prototype.pause = function () {
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this.emit('pause');
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};
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}
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if (!stream.Stream.prototype.resume) {
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BufferedStream.prototype.resume = function () {
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this.emit('resume');
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};
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}
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