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// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.
var events = require('events');
var util = require('util');
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function Stream() {
events.EventEmitter.call(this);
}
util.inherits(Stream, events.EventEmitter);
exports.Stream = Stream;
Stream.prototype.pipe = function(dest, options) {
var source = this;
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function ondata(chunk) {
if (dest.writable) {
if (false === dest.write(chunk)) source.pause();
}
}
source.on('data', ondata);
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function ondrain() {
if (source.readable) source.resume();
}
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dest.on('drain', ondrain);
// If the 'end' option is not supplied, dest.end() will be called when
// source gets the 'end' or 'close' events. Only dest.end() once, and
// only when all sources have ended.
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if (!options || options.end !== false) {
dest._pipeCount = dest._pipeCount || 0;
dest._pipeCount++;
source.on('end', onend);
source.on('close', onclose);
}
var didOnEnd = false;
function onend() {
if (didOnEnd) return;
didOnEnd = true;
dest._pipeCount--;
// remove the listeners
cleanup();
if (dest._pipeCount > 0) {
// waiting for other incoming streams to end.
return;
}
dest.end();
}
function onclose() {
if (didOnEnd) return;
didOnEnd = true;
dest._pipeCount--;
// remove the listeners
cleanup();
if (dest._pipeCount > 0) {
// waiting for other incoming streams to end.
return;
}
dest.destroy();
}
// don't leave dangling pipes when there are errors.
function onerror(er) {
cleanup();
if (this.listeners('error').length === 0) {
throw er; // Unhandled stream error in pipe.
}
}
source.on('error', onerror);
dest.on('error', onerror);
// guarantee that source streams can be paused and resumed, even
// if the only effect is to proxy the event back up the pipe chain.
if (!source.pause) {
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source.pause = function() {
source.emit('pause');
};
}
if (!source.resume) {
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source.resume = function() {
source.emit('resume');
};
}
function onpause() {
source.pause();
}
dest.on('pause', onpause);
function onresume() {
if (source.readable) source.resume();
}
dest.on('resume', onresume);
// remove all the event listeners that were added.
function cleanup() {
source.removeListener('data', ondata);
dest.removeListener('drain', ondrain);
source.removeListener('end', onend);
source.removeListener('close', onclose);
dest.removeListener('pause', onpause);
dest.removeListener('resume', onresume);
source.removeListener('error', onerror);
dest.removeListener('error', onerror);
source.removeListener('end', cleanup);
source.removeListener('close', cleanup);
dest.removeListener('end', cleanup);
dest.removeListener('close', cleanup);
}
source.on('end', cleanup);
source.on('close', cleanup);
dest.on('end', cleanup);
dest.on('close', cleanup);
dest.emit('pipe', source);
// Allow for unix-like usage: A.pipe(B).pipe(C)
return dest;
};