| // 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; |
| Readable.ReadableState = ReadableState; |
| |
| var EE = require('events').EventEmitter; |
| var Stream = require('stream'); |
| var util = require('util'); |
| 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 (isNaN(n) || n === null) { |
| // 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; |
| |
| 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) { |
| if (state.length === 0) |
| endReadable(this); |
| return null; |
| } |
| |
| // 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); |
| |
| var ret; |
| 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) { |
| 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 (Array.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 |
| state.pipes.forEach(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 = state.pipes.indexOf(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); |
| if (!chunk || !state.objectMode && !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']; |
| events.forEach(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'); |
| } |
| }); |
| } |
| } |