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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);
};