// 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 = Readable;

/*<replacement>*/ var isArray = require(‘isarray’); /*</replacement>*/

/*<replacement>*/ var Buffer = require(‘buffer’).Buffer; /*</replacement>*/

Readable.ReadableState = ReadableState;

var EE = require(‘events’).EventEmitter;

/*<replacement>*/ if (!EE.listenerCount) EE.listenerCount = function(emitter, type) {

return emitter.listeners(type).length;

}; /*</replacement>*/

var Stream = require(‘stream’);

/*<replacement>*/ var util = require(‘core-util-is’); util.inherits = require(‘inherits’); /*</replacement>*/

var StringDecoder;

util.inherits(Readable, Stream);

function ReadableState(options, stream) {

options = options || {};

// the point at which it stops calling _read() to fill the buffer
// Note: 0 is a valid value, means "don't call _read preemptively ever"
var hwm = options.highWaterMark;
this.highWaterMark = (hwm || hwm === 0) ? hwm : 16 * 1024;

// cast to ints.
this.highWaterMark = ~~this.highWaterMark;

this.buffer = [];
this.length = 0;
this.pipes = null;
this.pipesCount = 0;
this.flowing = false;
this.ended = false;
this.endEmitted = false;
this.reading = false;

// In streams that never have any data, and do push(null) right away,
// the consumer can miss the 'end' event if they do some I/O before
// consuming the stream.  So, we don't emit('end') until some reading
// happens.
this.calledRead = false;

// a flag to be able to tell if the onwrite cb is called immediately,
// or on a later tick.  We set this to true at first, becuase any
// actions that shouldn't happen until "later" should generally also
// not happen before the first write call.
this.sync = true;

// whenever we return null, then we set a flag to say
// that we're awaiting a 'readable' event emission.
this.needReadable = false;
this.emittedReadable = false;
this.readableListening = false;

// object stream flag. Used to make read(n) ignore n and to
// make all the buffer merging and length checks go away
this.objectMode = !!options.objectMode;

// Crypto is kind of old and crusty.  Historically, its default string
// encoding is 'binary' so we have to make this configurable.
// Everything else in the universe uses 'utf8', though.
this.defaultEncoding = options.defaultEncoding || 'utf8';

// when piping, we only care about 'readable' events that happen
// after read()ing all the bytes and not getting any pushback.
this.ranOut = false;

// the number of writers that are awaiting a drain event in .pipe()s
this.awaitDrain = 0;

// if true, a maybeReadMore has been scheduled
this.readingMore = false;

this.decoder = null;
this.encoding = null;
if (options.encoding) {
  if (!StringDecoder)
    StringDecoder = require('string_decoder/').StringDecoder;
  this.decoder = new StringDecoder(options.encoding);
  this.encoding = options.encoding;
}

}

function Readable(options) {

if (!(this instanceof Readable))
  return new Readable(options);

this._readableState = new ReadableState(options, this);

// legacy
this.readable = true;

Stream.call(this);

}

// Manually shove something into the read() buffer. // This returns true if the highWaterMark has not been hit yet, // similar to how Writable.write() returns true if you should // write() some more. Readable.prototype.push = function(chunk, encoding) {

var state = this._readableState;

if (typeof chunk === 'string' && !state.objectMode) {
  encoding = encoding || state.defaultEncoding;
  if (encoding !== state.encoding) {
    chunk = new Buffer(chunk, encoding);
    encoding = '';
  }
}

return readableAddChunk(this, state, chunk, encoding, false);

};

// Unshift should always be something directly out of read() Readable.prototype.unshift = function(chunk) {

var state = this._readableState;
return readableAddChunk(this, state, chunk, '', true);

};

function readableAddChunk(stream, state, chunk, encoding, addToFront) {

var er = chunkInvalid(state, chunk);
if (er) {
  stream.emit('error', er);
} else if (chunk === null || chunk === undefined) {
  state.reading = false;
  if (!state.ended)
    onEofChunk(stream, state);
} else if (state.objectMode || chunk && chunk.length > 0) {
  if (state.ended && !addToFront) {
    var e = new Error('stream.push() after EOF');
    stream.emit('error', e);
  } else if (state.endEmitted && addToFront) {
    var e = new Error('stream.unshift() after end event');
    stream.emit('error', e);
  } else {
    if (state.decoder && !addToFront && !encoding)
      chunk = state.decoder.write(chunk);

    // update the buffer info.
    state.length += state.objectMode ? 1 : chunk.length;
    if (addToFront) {
      state.buffer.unshift(chunk);
    } else {
      state.reading = false;
      state.buffer.push(chunk);
    }

    if (state.needReadable)
      emitReadable(stream);

    maybeReadMore(stream, state);
  }
} else if (!addToFront) {
  state.reading = false;
}

return needMoreData(state);

}

// if it’s past the high water mark, we can push in some more. // Also, if we have no data yet, we can stand some // more bytes. This is to work around cases where hwm=0, // such as the repl. Also, if the push() triggered a // readable event, and the user called read(largeNumber) such that // needReadable was set, then we ought to push more, so that another // ‘readable’ event will be triggered. function needMoreData(state) {

return !state.ended &&
       (state.needReadable ||
        state.length < state.highWaterMark ||
        state.length === 0);

}

// backwards compatibility. Readable.prototype.setEncoding = function(enc) {

if (!StringDecoder)
  StringDecoder = require('string_decoder/').StringDecoder;
this._readableState.decoder = new StringDecoder(enc);
this._readableState.encoding = enc;

};

// Don’t raise the hwm > 128MB var MAX_HWM = 0x800000; function roundUpToNextPowerOf2(n) {

if (n >= MAX_HWM) {
  n = MAX_HWM;
} else {
  // Get the next highest power of 2
  n--;
  for (var p = 1; p < 32; p <<= 1) n |= n >> p;
  n++;
}
return n;

}

function howMuchToRead(n, state) {

if (state.length === 0 && state.ended)
  return 0;

if (state.objectMode)
  return n === 0 ? 0 : 1;

if (n === null || isNaN(n)) {
  // only flow one buffer at a time
  if (state.flowing && state.buffer.length)
    return state.buffer[0].length;
  else
    return state.length;
}

if (n <= 0)
  return 0;

// If we're asking for more than the target buffer level,
// then raise the water mark.  Bump up to the next highest
// power of 2, to prevent increasing it excessively in tiny
// amounts.
if (n > state.highWaterMark)
  state.highWaterMark = roundUpToNextPowerOf2(n);

// don't have that much.  return null, unless we've ended.
if (n > state.length) {
  if (!state.ended) {
    state.needReadable = true;
    return 0;
  } else
    return state.length;
}

return n;

}

// you can override either this method, or the async _read(n) below. Readable.prototype.read = function(n) {

var state = this._readableState;
state.calledRead = true;
var nOrig = n;
var ret;

if (typeof n !== 'number' || n > 0)
  state.emittedReadable = false;

// if we're doing read(0) to trigger a readable event, but we
// already have a bunch of data in the buffer, then just trigger
// the 'readable' event and move on.
if (n === 0 &&
    state.needReadable &&
    (state.length >= state.highWaterMark || state.ended)) {
  emitReadable(this);
  return null;
}

n = howMuchToRead(n, state);

// if we've ended, and we're now clear, then finish it up.
if (n === 0 && state.ended) {
  ret = null;

  // In cases where the decoder did not receive enough data
  // to produce a full chunk, then immediately received an
  // EOF, state.buffer will contain [<Buffer >, <Buffer 00 ...>].
  // howMuchToRead will see this and coerce the amount to
  // read to zero (because it's looking at the length of the
  // first <Buffer > in state.buffer), and we'll end up here.
  //
  // This can only happen via state.decoder -- no other venue
  // exists for pushing a zero-length chunk into state.buffer
  // and triggering this behavior. In this case, we return our
  // remaining data and end the stream, if appropriate.
  if (state.length > 0 && state.decoder) {
    ret = fromList(n, state);
    state.length -= ret.length;
  }

  if (state.length === 0)
    endReadable(this);

  return ret;
}

// All the actual chunk generation logic needs to be
// *below* the call to _read.  The reason is that in certain
// synthetic stream cases, such as passthrough streams, _read
// may be a completely synchronous operation which may change
// the state of the read buffer, providing enough data when
// before there was *not* enough.
//
// So, the steps are:
// 1. Figure out what the state of things will be after we do
// a read from the buffer.
//
// 2. If that resulting state will trigger a _read, then call _read.
// Note that this may be asynchronous, or synchronous.  Yes, it is
// deeply ugly to write APIs this way, but that still doesn't mean
// that the Readable class should behave improperly, as streams are
// designed to be sync/async agnostic.
// Take note if the _read call is sync or async (ie, if the read call
// has returned yet), so that we know whether or not it's safe to emit
// 'readable' etc.
//
// 3. Actually pull the requested chunks out of the buffer and return.

// if we need a readable event, then we need to do some reading.
var doRead = state.needReadable;

// if we currently have less than the highWaterMark, then also read some
if (state.length - n <= state.highWaterMark)
  doRead = true;

// however, if we've ended, then there's no point, and if we're already
// reading, then it's unnecessary.
if (state.ended || state.reading)
  doRead = false;

if (doRead) {
  state.reading = true;
  state.sync = true;
  // if the length is currently zero, then we *need* a readable event.
  if (state.length === 0)
    state.needReadable = true;
  // call internal read method
  this._read(state.highWaterMark);
  state.sync = false;
}

// If _read called its callback synchronously, then `reading`
// will be false, and we need to re-evaluate how much data we
// can return to the user.
if (doRead && !state.reading)
  n = howMuchToRead(nOrig, state);

if (n > 0)
  ret = fromList(n, state);
else
  ret = null;

if (ret === null) {
  state.needReadable = true;
  n = 0;
}

state.length -= n;

// If we have nothing in the buffer, then we want to know
// as soon as we *do* get something into the buffer.
if (state.length === 0 && !state.ended)
  state.needReadable = true;

// If we happened to read() exactly the remaining amount in the
// buffer, and the EOF has been seen at this point, then make sure
// that we emit 'end' on the very next tick.
if (state.ended && !state.endEmitted && state.length === 0)
  endReadable(this);

return ret;

};

function chunkInvalid(state, chunk) {

var er = null;
if (!Buffer.isBuffer(chunk) &&
    'string' !== typeof chunk &&
    chunk !== null &&
    chunk !== undefined &&
    !state.objectMode) {
  er = new TypeError('Invalid non-string/buffer chunk');
}
return er;

}

function onEofChunk(stream, state) {

if (state.decoder && !state.ended) {
  var chunk = state.decoder.end();
  if (chunk && chunk.length) {
    state.buffer.push(chunk);
    state.length += state.objectMode ? 1 : chunk.length;
  }
}
state.ended = true;

// if we've ended and we have some data left, then emit
// 'readable' now to make sure it gets picked up.
if (state.length > 0)
  emitReadable(stream);
else
  endReadable(stream);

}

// Don’t emit readable right away in sync mode, because this can trigger // another read() call => stack overflow. This way, it might trigger // a nextTick recursion warning, but that’s not so bad. function emitReadable(stream) {

var state = stream._readableState;
state.needReadable = false;
if (state.emittedReadable)
  return;

state.emittedReadable = true;
if (state.sync)
  process.nextTick(function() {
    emitReadable_(stream);
  });
else
  emitReadable_(stream);

}

function emitReadable_(stream) {

stream.emit('readable');

}

// at this point, the user has presumably seen the ‘readable’ event, // and called read() to consume some data. that may have triggered // in turn another _read(n) call, in which case reading = true if // it’s in progress. // However, if we’re not ended, or reading, and the length < hwm, // then go ahead and try to read some more preemptively. function maybeReadMore(stream, state) {

if (!state.readingMore) {
  state.readingMore = true;
  process.nextTick(function() {
    maybeReadMore_(stream, state);
  });
}

}

function maybeReadMore_(stream, state) {

var len = state.length;
while (!state.reading && !state.flowing && !state.ended &&
       state.length < state.highWaterMark) {
  stream.read(0);
  if (len === state.length)
    // didn't get any data, stop spinning.
    break;
  else
    len = state.length;
}
state.readingMore = false;

}

// abstract method. to be overridden in specific implementation classes. // call cb(er, data) where data is <= n in length. // for virtual (non-string, non-buffer) streams, “length” is somewhat // arbitrary, and perhaps not very meaningful. Readable.prototype._read = function(n) {

this.emit('error', new Error('not implemented'));

};

Readable.prototype.pipe = function(dest, pipeOpts) {

var src = this;
var state = this._readableState;

switch (state.pipesCount) {
  case 0:
    state.pipes = dest;
    break;
  case 1:
    state.pipes = [state.pipes, dest];
    break;
  default:
    state.pipes.push(dest);
    break;
}
state.pipesCount += 1;

var doEnd = (!pipeOpts || pipeOpts.end !== false) &&
            dest !== process.stdout &&
            dest !== process.stderr;

var endFn = doEnd ? onend : cleanup;
if (state.endEmitted)
  process.nextTick(endFn);
else
  src.once('end', endFn);

dest.on('unpipe', onunpipe);
function onunpipe(readable) {
  if (readable !== src) return;
  cleanup();
}

function onend() {
  dest.end();
}

// when the dest drains, it reduces the awaitDrain counter
// on the source.  This would be more elegant with a .once()
// handler in flow(), but adding and removing repeatedly is
// too slow.
var ondrain = pipeOnDrain(src);
dest.on('drain', ondrain);

function cleanup() {
  // cleanup event handlers once the pipe is broken
  dest.removeListener('close', onclose);
  dest.removeListener('finish', onfinish);
  dest.removeListener('drain', ondrain);
  dest.removeListener('error', onerror);
  dest.removeListener('unpipe', onunpipe);
  src.removeListener('end', onend);
  src.removeListener('end', cleanup);

  // if the reader is waiting for a drain event from this
  // specific writer, then it would cause it to never start
  // flowing again.
  // So, if this is awaiting a drain, then we just call it now.
  // If we don't know, then assume that we are waiting for one.
  if (!dest._writableState || dest._writableState.needDrain)
    ondrain();
}

// if the dest has an error, then stop piping into it.
// however, don't suppress the throwing behavior for this.
function onerror(er) {
  unpipe();
  dest.removeListener('error', onerror);
  if (EE.listenerCount(dest, 'error') === 0)
    dest.emit('error', er);
}
// This is a brutally ugly hack to make sure that our error handler
// is attached before any userland ones.  NEVER DO THIS.
if (!dest._events || !dest._events.error)
  dest.on('error', onerror);
else if (isArray(dest._events.error))
  dest._events.error.unshift(onerror);
else
  dest._events.error = [onerror, dest._events.error];

// Both close and finish should trigger unpipe, but only once.
function onclose() {
  dest.removeListener('finish', onfinish);
  unpipe();
}
dest.once('close', onclose);
function onfinish() {
  dest.removeListener('close', onclose);
  unpipe();
}
dest.once('finish', onfinish);

function unpipe() {
  src.unpipe(dest);
}

// tell the dest that it's being piped to
dest.emit('pipe', src);

// start the flow if it hasn't been started already.
if (!state.flowing) {
  // the handler that waits for readable events after all
  // the data gets sucked out in flow.
  // This would be easier to follow with a .once() handler
  // in flow(), but that is too slow.
  this.on('readable', pipeOnReadable);

  state.flowing = true;
  process.nextTick(function() {
    flow(src);
  });
}

return dest;

};

function pipeOnDrain(src) {

return function() {
  var dest = this;
  var state = src._readableState;
  state.awaitDrain--;
  if (state.awaitDrain === 0)
    flow(src);
};

}

function flow(src) {

var state = src._readableState;
var chunk;
state.awaitDrain = 0;

function write(dest, i, list) {
  var written = dest.write(chunk);
  if (false === written) {
    state.awaitDrain++;
  }
}

while (state.pipesCount && null !== (chunk = src.read())) {

  if (state.pipesCount === 1)
    write(state.pipes, 0, null);
  else
    forEach(state.pipes, write);

  src.emit('data', chunk);

  // if anyone needs a drain, then we have to wait for that.
  if (state.awaitDrain > 0)
    return;
}

// if every destination was unpiped, either before entering this
// function, or in the while loop, then stop flowing.
//
// NB: This is a pretty rare edge case.
if (state.pipesCount === 0) {
  state.flowing = false;

  // if there were data event listeners added, then switch to old mode.
  if (EE.listenerCount(src, 'data') > 0)
    emitDataEvents(src);
  return;
}

// at this point, no one needed a drain, so we just ran out of data
// on the next readable event, start it over again.
state.ranOut = true;

}

function pipeOnReadable() {

if (this._readableState.ranOut) {
  this._readableState.ranOut = false;
  flow(this);
}

}

Readable.prototype.unpipe = function(dest) {

var state = this._readableState;

// if we're not piping anywhere, then do nothing.
if (state.pipesCount === 0)
  return this;

// just one destination.  most common case.
if (state.pipesCount === 1) {
  // passed in one, but it's not the right one.
  if (dest && dest !== state.pipes)
    return this;

  if (!dest)
    dest = state.pipes;

  // got a match.
  state.pipes = null;
  state.pipesCount = 0;
  this.removeListener('readable', pipeOnReadable);
  state.flowing = false;
  if (dest)
    dest.emit('unpipe', this);
  return this;
}

// slow case. multiple pipe destinations.

if (!dest) {
  // remove all.
  var dests = state.pipes;
  var len = state.pipesCount;
  state.pipes = null;
  state.pipesCount = 0;
  this.removeListener('readable', pipeOnReadable);
  state.flowing = false;

  for (var i = 0; i < len; i++)
    dests[i].emit('unpipe', this);
  return this;
}

// try to find the right one.
var i = indexOf(state.pipes, dest);
if (i === -1)
  return this;

state.pipes.splice(i, 1);
state.pipesCount -= 1;
if (state.pipesCount === 1)
  state.pipes = state.pipes[0];

dest.emit('unpipe', this);

return this;

};

// set up data events if they are asked for // Ensure readable listeners eventually get something Readable.prototype.on = function(ev, fn) {

var res = Stream.prototype.on.call(this, ev, fn);

if (ev === 'data' && !this._readableState.flowing)
  emitDataEvents(this);

if (ev === 'readable' && this.readable) {
  var state = this._readableState;
  if (!state.readableListening) {
    state.readableListening = true;
    state.emittedReadable = false;
    state.needReadable = true;
    if (!state.reading) {
      this.read(0);
    } else if (state.length) {
      emitReadable(this, state);
    }
  }
}

return res;

}; Readable.prototype.addListener = Readable.prototype.on;

// pause() and resume() are remnants of the legacy readable stream API // If the user uses them, then switch into old mode. Readable.prototype.resume = function() {

emitDataEvents(this);
this.read(0);
this.emit('resume');

};

Readable.prototype.pause = function() {

emitDataEvents(this, true);
this.emit('pause');

};

function emitDataEvents(stream, startPaused) {

var state = stream._readableState;

if (state.flowing) {
  // https://github.com/isaacs/readable-stream/issues/16
  throw new Error('Cannot switch to old mode now.');
}

var paused = startPaused || false;
var readable = false;

// convert to an old-style stream.
stream.readable = true;
stream.pipe = Stream.prototype.pipe;
stream.on = stream.addListener = Stream.prototype.on;

stream.on('readable', function() {
  readable = true;

  var c;
  while (!paused && (null !== (c = stream.read())))
    stream.emit('data', c);

  if (c === null) {
    readable = false;
    stream._readableState.needReadable = true;
  }
});

stream.pause = function() {
  paused = true;
  this.emit('pause');
};

stream.resume = function() {
  paused = false;
  if (readable)
    process.nextTick(function() {
      stream.emit('readable');
    });
  else
    this.read(0);
  this.emit('resume');
};

// now make it start, just in case it hadn't already.
stream.emit('readable');

}

// wrap an old-style stream as the async data source. // This is not part of the readable stream interface. // It is an ugly unfortunate mess of history. Readable.prototype.wrap = function(stream) {

var state = this._readableState;
var paused = false;

var self = this;
stream.on('end', function() {
  if (state.decoder && !state.ended) {
    var chunk = state.decoder.end();
    if (chunk && chunk.length)
      self.push(chunk);
  }

  self.push(null);
});

stream.on('data', function(chunk) {
  if (state.decoder)
    chunk = state.decoder.write(chunk);

  // don't skip over falsy values in objectMode
  //if (state.objectMode && util.isNullOrUndefined(chunk))
  if (state.objectMode && (chunk === null || chunk === undefined))
    return;
  else if (!state.objectMode && (!chunk || !chunk.length))
    return;

  var ret = self.push(chunk);
  if (!ret) {
    paused = true;
    stream.pause();
  }
});

// proxy all the other methods.
// important when wrapping filters and duplexes.
for (var i in stream) {
  if (typeof stream[i] === 'function' &&
      typeof this[i] === 'undefined') {
    this[i] = function(method) { return function() {
      return stream[method].apply(stream, arguments);
    }}(i);
  }
}

// proxy certain important events.
var events = ['error', 'close', 'destroy', 'pause', 'resume'];
forEach(events, function(ev) {
  stream.on(ev, self.emit.bind(self, ev));
});

// when we try to consume some more bytes, simply unpause the
// underlying stream.
self._read = function(n) {
  if (paused) {
    paused = false;
    stream.resume();
  }
};

return self;

};

// exposed for testing purposes only. Readable._fromList = fromList;

// Pluck off n bytes from an array of buffers. // Length is the combined lengths of all the buffers in the list. function fromList(n, state) {

var list = state.buffer;
var length = state.length;
var stringMode = !!state.decoder;
var objectMode = !!state.objectMode;
var ret;

// nothing in the list, definitely empty.
if (list.length === 0)
  return null;

if (length === 0)
  ret = null;
else if (objectMode)
  ret = list.shift();
else if (!n || n >= length) {
  // read it all, truncate the array.
  if (stringMode)
    ret = list.join('');
  else
    ret = Buffer.concat(list, length);
  list.length = 0;
} else {
  // read just some of it.
  if (n < list[0].length) {
    // just take a part of the first list item.
    // slice is the same for buffers and strings.
    var buf = list[0];
    ret = buf.slice(0, n);
    list[0] = buf.slice(n);
  } else if (n === list[0].length) {
    // first list is a perfect match
    ret = list.shift();
  } else {
    // complex case.
    // we have enough to cover it, but it spans past the first buffer.
    if (stringMode)
      ret = '';
    else
      ret = new Buffer(n);

    var c = 0;
    for (var i = 0, l = list.length; i < l && c < n; i++) {
      var buf = list[0];
      var cpy = Math.min(n - c, buf.length);

      if (stringMode)
        ret += buf.slice(0, cpy);
      else
        buf.copy(ret, c, 0, cpy);

      if (cpy < buf.length)
        list[0] = buf.slice(cpy);
      else
        list.shift();

      c += cpy;
    }
  }
}

return ret;

}

function endReadable(stream) {

var state = stream._readableState;

// If we get here before consuming all the bytes, then that is a
// bug in node.  Should never happen.
if (state.length > 0)
  throw new Error('endReadable called on non-empty stream');

if (!state.endEmitted && state.calledRead) {
  state.ended = true;
  process.nextTick(function() {
    // Check that we didn't get one last unshift.
    if (!state.endEmitted && state.length === 0) {
      state.endEmitted = true;
      stream.readable = false;
      stream.emit('end');
    }
  });
}

}

function forEach (xs, f) {

for (var i = 0, l = xs.length; i < l; i++) {
  f(xs[i], i);
}

}

function indexOf (xs, x) {

for (var i = 0, l = xs.length; i < l; i++) {
  if (xs[i] === x) return i;
}
return -1;

}