var util = require('util'); var Stream = require('stream').Stream; var DelayedStream = require('delayed-stream'); module.exports = CombinedStream; function CombinedStream() { this.writable = false; this.readable = true; this.dataSize = 0; this.maxDataSize = 2 * 1024 * 1024; this.pauseStreams = true; this._released = false; this._streams = []; this._currentStream = null; this._insideLoop = false; this._pendingNext = false; } util.inherits(CombinedStream, Stream); CombinedStream.create = function(options) { var combinedStream = new this(); options = options || {}; for (var option in options) { combinedStream[option] = options[option]; } return combinedStream; }; CombinedStream.isStreamLike = function(stream) { return (typeof stream !== 'function') && (typeof stream !== 'string') && (typeof stream !== 'boolean') && (typeof stream !== 'number') && (!Buffer.isBuffer(stream)); }; CombinedStream.prototype.append = function(stream) { var isStreamLike = CombinedStream.isStreamLike(stream); if (isStreamLike) { if (!(stream instanceof DelayedStream)) { var newStream = DelayedStream.create(stream, { maxDataSize: Infinity, pauseStream: this.pauseStreams, }); stream.on('data', this._checkDataSize.bind(this)); stream = newStream; } this._handleErrors(stream); if (this.pauseStreams) { stream.pause(); } } this._streams.push(stream); return this; }; CombinedStream.prototype.pipe = function(dest, options) { Stream.prototype.pipe.call(this, dest, options); this.resume(); return dest; }; CombinedStream.prototype._getNext = function() { this._currentStream = null; if (this._insideLoop) { this._pendingNext = true; return; // defer call } this._insideLoop = true; try { do { this._pendingNext = false; this._realGetNext(); } while (this._pendingNext); } finally { this._insideLoop = false; } }; CombinedStream.prototype._realGetNext = function() { var stream = this._streams.shift(); if (typeof stream == 'undefined') { this.end(); return; } if (typeof stream !== 'function') { this._pipeNext(stream); return; } var getStream = stream; getStream(function(stream) { var isStreamLike = CombinedStream.isStreamLike(stream); if (isStreamLike) { stream.on('data', this._checkDataSize.bind(this)); this._handleErrors(stream); } this._pipeNext(stream); }.bind(this)); }; CombinedStream.prototype._pipeNext = function(stream) { this._currentStream = stream; var isStreamLike = CombinedStream.isStreamLike(stream); if (isStreamLike) { stream.on('end', this._getNext.bind(this)); stream.pipe(this, {end: false}); return; } var value = stream; this.write(value); this._getNext(); }; CombinedStream.prototype._handleErrors = function(stream) { var self = this; stream.on('error', function(err) { self._emitError(err); }); }; CombinedStream.prototype.write = function(data) { this.emit('data', data); }; CombinedStream.prototype.pause = function() { if (!this.pauseStreams) { return; } if(this.pauseStreams && this._currentStream && typeof(this._currentStream.pause) == 'function') this._currentStream.pause(); this.emit('pause'); }; CombinedStream.prototype.resume = function() { if (!this._released) { this._released = true; this.writable = true; this._getNext(); } if(this.pauseStreams && this._currentStream && typeof(this._currentStream.resume) == 'function') this._currentStream.resume(); this.emit('resume'); }; CombinedStream.prototype.end = function() { this._reset(); this.emit('end'); }; CombinedStream.prototype.destroy = function() { this._reset(); this.emit('close'); }; CombinedStream.prototype._reset = function() { this.writable = false; this._streams = []; this._currentStream = null; }; CombinedStream.prototype._checkDataSize = function() { this._updateDataSize(); if (this.dataSize <= this.maxDataSize) { return; } var message = 'DelayedStream#maxDataSize of ' + this.maxDataSize + ' bytes exceeded.'; this._emitError(new Error(message)); }; CombinedStream.prototype._updateDataSize = function() { this.dataSize = 0; var self = this; this._streams.forEach(function(stream) { if (!stream.dataSize) { return; } self.dataSize += stream.dataSize; }); if (this._currentStream && this._currentStream.dataSize) { this.dataSize += this._currentStream.dataSize; } }; CombinedStream.prototype._emitError = function(err) { this._reset(); this.emit('error', err); };