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node_modules/stream-browserify/index.js 3.54 KB
aaac7fed   liuqimichale   add
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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.
  
  module.exports = Stream;
  
  var EE = require('events').EventEmitter;
  var inherits = require('inherits');
  
  inherits(Stream, EE);
  Stream.Readable = require('readable-stream/readable.js');
  Stream.Writable = require('readable-stream/writable.js');
  Stream.Duplex = require('readable-stream/duplex.js');
  Stream.Transform = require('readable-stream/transform.js');
  Stream.PassThrough = require('readable-stream/passthrough.js');
  
  // Backwards-compat with node 0.4.x
  Stream.Stream = Stream;
  
  
  
  // old-style streams.  Note that the pipe method (the only relevant
  // part of this class) is overridden in the Readable class.
  
  function Stream() {
    EE.call(this);
  }
  
  Stream.prototype.pipe = function(dest, options) {
    var source = this;
  
    function ondata(chunk) {
      if (dest.writable) {
        if (false === dest.write(chunk) && source.pause) {
          source.pause();
        }
      }
    }
  
    source.on('data', ondata);
  
    function ondrain() {
      if (source.readable && source.resume) {
        source.resume();
      }
    }
  
    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.
    if (!dest._isStdio && (!options || options.end !== false)) {
      source.on('end', onend);
      source.on('close', onclose);
    }
  
    var didOnEnd = false;
    function onend() {
      if (didOnEnd) return;
      didOnEnd = true;
  
      dest.end();
    }
  
  
    function onclose() {
      if (didOnEnd) return;
      didOnEnd = true;
  
      if (typeof dest.destroy === 'function') dest.destroy();
    }
  
    // don't leave dangling pipes when there are errors.
    function onerror(er) {
      cleanup();
      if (EE.listenerCount(this, 'error') === 0) {
        throw er; // Unhandled stream error in pipe.
      }
    }
  
    source.on('error', onerror);
    dest.on('error', onerror);
  
    // 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);
  
      source.removeListener('error', onerror);
      dest.removeListener('error', onerror);
  
      source.removeListener('end', cleanup);
      source.removeListener('close', cleanup);
  
      dest.removeListener('close', cleanup);
    }
  
    source.on('end', cleanup);
    source.on('close', cleanup);
  
    dest.on('close', cleanup);
  
    dest.emit('pipe', source);
  
    // Allow for unix-like usage: A.pipe(B).pipe(C)
    return dest;
  };