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streams2: The new stream base classes

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commit 60b0c332f5cc6efee8fb2e9e7f04848d31de96fa 1 parent 4de274c
@isaacs isaacs authored
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81 lib/_stream_duplex.js
@@ -0,0 +1,81 @@
+// 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.
+
+// a duplex stream is just a stream that is both readable and writable.
+// Since JS doesn't have multiple prototypal inheritance, this class
+// prototypally inherits from Readable, and then parasitically from
+// Writable.
+
+module.exports = Duplex;
+var util = require('util');
+var Readable = require('_stream_readable');
+var Writable = require('_stream_writable');
+
+util.inherits(Duplex, Readable);
+
+Object.keys(Writable.prototype).forEach(function(method) {
+ if (!Duplex.prototype[method])
+ Duplex.prototype[method] = Writable.prototype[method];
+});
+
+function Duplex(options) {
+ Readable.call(this, options);
+ Writable.call(this, options);
+
+ this.allowHalfOpen = true;
+ if (options && options.allowHalfOpen === false)
+ this.allowHalfOpen = false;
+
+ this.once('finish', onfinish);
+ this.once('end', onend);
+}
+
+// the no-half-open enforcers.
+function onfinish() {
+ // if we allow half-open state, or if the readable side ended,
+ // then we're ok.
+ if (this.allowHalfOpen || this._readableState.ended)
+ return;
+
+ // mark that we're done.
+ this._readableState.ended = true;
+
+ // tell the user
+ if (this._readableState.length === 0)
+ this.emit('end');
+ else
+ this.emit('readable');
+}
+
+function onend() {
+ // if we allow half-open state, or if the writable side ended,
+ // then we're ok.
+ if (this.allowHalfOpen || this._writableState.ended)
+ return;
+
+ // just in case the user is about to call write() again.
+ this.write = function() {
+ return false;
+ };
+
+ // no more data can be written.
+ this.end();
+}
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39 lib/_stream_passthrough.js
@@ -0,0 +1,39 @@
+// 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.
+
+// a passthrough stream.
+// basically just the most minimal sort of Transform stream.
+// Every written chunk gets output as-is.
+
+module.exports = PassThrough;
+
+var Transform = require('_stream_transform');
+var util = require('util');
+util.inherits(PassThrough, Transform);
+
+function PassThrough(options) {
+ Transform.call(this, options);
+}
+
+PassThrough.prototype._transform = function(chunk, output, cb) {
+ output(chunk);
+ cb();
+};
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429 lib/_stream_readable.js
@@ -0,0 +1,429 @@
+// 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;
+
+var Stream = require('stream');
+var util = require('util');
+var assert = require('assert');
+
+util.inherits(Readable, Stream);
+
+function ReadableState(options, stream) {
+ options = options || {};
+
+ this.bufferSize = options.bufferSize || 16 * 1024;
+ assert(typeof this.bufferSize === 'number');
+ // cast to an int
+ this.bufferSize = ~~this.bufferSize;
+
+ this.lowWaterMark = options.lowWaterMark || 1024;
+ this.buffer = [];
+ this.length = 0;
+ this.pipes = [];
+ this.flowing = false;
+ this.ended = false;
+ this.stream = stream;
+ this.reading = false;
+
+ // whenever we return null, then we set a flag to say
+ // that we're awaiting a 'readable' event emission.
+ this.needReadable = false;
+}
+
+function Readable(options) {
+ this._readableState = new ReadableState(options, this);
+ Stream.apply(this);
+}
+
+// you can override either this method, or _read(n, cb) below.
+Readable.prototype.read = function(n) {
+ var state = this._readableState;
+
+ if (state.length === 0 && state.ended) {
+ process.nextTick(this.emit.bind(this, 'end'));
+ return null;
+ }
+
+ if (isNaN(n) || n <= 0)
+ n = state.length
+
+ // XXX: controversial.
+ // don't have that much. return null, unless we've ended.
+ // However, if the low water mark is lower than the number of bytes,
+ // then we still need to return what we have, or else it won't kick
+ // off another _read() call. For example,
+ // lwm=5
+ // len=9
+ // read(10)
+ // We don't have that many bytes, so it'd be tempting to return null,
+ // but then it won't ever cause _read to be called, so in that case,
+ // we just return what we have, and let the programmer deal with it.
+ if (n > state.length) {
+ if (!state.ended && state.length < state.lowWaterMark) {
+ state.needReadable = true;
+ n = 0;
+ } else
+ n = state.length;
+ }
+
+ var ret = n > 0 ? fromList(n, state.buffer, state.length) : null;
+
+ if (ret === null || ret.length === 0)
+ state.needReadable = true;
+
+ state.length -= n;
+
+ if (!state.ended &&
+ state.length < state.lowWaterMark &&
+ !state.reading) {
+ state.reading = true;
+ // call internal read method
+ this._read(state.bufferSize, function onread(er, chunk) {
+ state.reading = false;
+ if (er)
+ return this.emit('error', er);
+
+ if (!chunk || !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)
+ this.emit('readable');
+ return;
+ }
+
+ state.length += chunk.length;
+ state.buffer.push(chunk);
+ if (state.length < state.lowWaterMark)
+ this._read(state.bufferSize, onread.bind(this));
+
+ // now we have something to call this.read() to get.
+ if (state.needReadable) {
+ state.needReadable = false;
+ this.emit('readable');
+ }
+ }.bind(this));
+ }
+
+ return ret;
+};
+
+// 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, cb) {
+ process.nextTick(cb.bind(this, new Error('not implemented')));
+};
+
+Readable.prototype.pipe = function(dest, pipeOpts) {
+ var src = this;
+ var state = this._readableState;
+ if (!pipeOpts)
+ pipeOpts = {};
+ state.pipes.push(dest);
+
+ if ((!pipeOpts || pipeOpts.end !== false) &&
+ dest !== process.stdout &&
+ dest !== process.stderr) {
+ src.once('end', onend);
+ dest.on('unpipe', function(readable) {
+ if (readable === src)
+ src.removeListener('end', onend);
+ });
+ }
+
+ function onend() {
+ dest.end();
+ }
+
+ dest.emit('pipe', src);
+
+ // start the flow.
+ if (!state.flowing)
+ process.nextTick(flow.bind(null, src, pipeOpts));
+
+ return dest;
+};
+
+function flow(src, pipeOpts) {
+ var state = src._readableState;
+ var chunk;
+ var dest;
+ var needDrain = 0;
+
+ function ondrain() {
+ needDrain--;
+ if (needDrain === 0)
+ flow(src, pipeOpts);
+ }
+
+ while (state.pipes.length &&
+ null !== (chunk = src.read(pipeOpts.chunkSize))) {
+ state.pipes.forEach(function(dest, i, list) {
+ var written = dest.write(chunk);
+ if (false === written) {
+ needDrain++;
+ dest.once('drain', ondrain);
+ }
+ });
+ src.emit('data', chunk);
+
+ // if anyone needs a drain, then we have to wait for that.
+ if (needDrain > 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.pipes.length === 0) {
+ state.flowing = false;
+
+ // if there were data event listeners added, then switch to old mode.
+ if (this.listeners('data').length)
+ emitDataEvents(this);
+ 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.
+ src.once('readable', flow.bind(null, src, pipeOpts));
+}
+
+Readable.prototype.unpipe = function(dest) {
+ var state = this._readableState;
+ if (!dest) {
+ // remove all of them.
+ state.pipes.forEach(function(dest, i, list) {
+ dest.emit('unpipe', this);
+ }, this);
+ state.pipes.length = 0;
+ } else {
+ var i = state.pipes.indexOf(dest);
+ if (i !== -1) {
+ dest.emit('unpipe', this);
+ state.pipes.splice(i, 1);
+ }
+ }
+ return this;
+};
+
+// kludge for on('data', fn) consumers. Sad.
+// This is *not* part of the new readable stream interface.
+// It is an ugly unfortunate mess of history.
+Readable.prototype.on = function(ev, fn) {
+ // https://github.com/isaacs/readable-stream/issues/16
+ // if we're already flowing, then no need to set up data events.
+ if (ev === 'data' && !this._readableState.flowing)
+ emitDataEvents(this);
+
+ return Stream.prototype.on.call(this, ev, fn);
+};
+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);
+ return this.resume();
+};
+
+Readable.prototype.pause = function() {
+ emitDataEvents(this);
+ return this.pause();
+};
+
+function emitDataEvents(stream) {
+ 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 = false;
+ var readable = false;
+
+ // convert to an old-style stream.
+ stream.readable = true;
+ stream.pipe = Stream.prototype.pipe;
+ stream.on = stream.addEventListener = 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;
+ };
+
+ stream.resume = function() {
+ paused = false;
+ if (readable)
+ stream.emit('readable');
+ };
+
+ // now make it start, just in case it hadn't already.
+ process.nextTick(function() {
+ 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;
+
+ stream.on('end', function() {
+ state.ended = true;
+ if (state.length === 0)
+ this.emit('end');
+ }.bind(this));
+
+ stream.on('data', function(chunk) {
+ state.buffer.push(chunk);
+ state.length += chunk.length;
+ this.emit('readable');
+
+ // if not consumed, then pause the stream.
+ if (state.length > state.lowWaterMark && !paused) {
+ paused = true;
+ stream.pause();
+ }
+ }.bind(this));
+
+ // 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, this.emit.bind(this, ev));
+ }.bind(this));
+
+ // consume some bytes. if not all is consumed, then
+ // pause the underlying stream.
+ this.read = function(n) {
+ if (state.length === 0) {
+ state.needReadable = true;
+ return null;
+ }
+
+ if (isNaN(n) || n <= 0)
+ n = state.length;
+
+ if (n > state.length) {
+ if (!state.ended) {
+ state.needReadable = true;
+ return null;
+ } else
+ n = state.length;
+ }
+
+ var ret = fromList(n, state.buffer, state.length);
+ state.length -= n;
+
+ if (state.length < state.lowWaterMark && paused) {
+ stream.resume();
+ paused = false;
+ }
+
+ if (state.length === 0 && state.ended)
+ process.nextTick(this.emit.bind(this, 'end'));
+
+ return ret;
+ };
+};
+
+
+
+// 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.
+// If there's no data, then
+function fromList(n, list, length) {
+ var ret;
+
+ // nothing in the list, definitely empty.
+ if (list.length === 0) {
+ return null;
+ }
+
+ if (length === 0) {
+ ret = null;
+ } else if (!n || n >= length) {
+ // read it all, truncate the array.
+ 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.
+ 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.
+ 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);
+ buf.copy(ret, c, 0, cpy);
+ if (cpy < buf.length) {
+ list[0] = buf.slice(cpy);
+ } else {
+ list.shift();
+ }
+ c += cpy;
+ }
+ }
+ }
+
+ return ret;
+}
View
123 lib/_stream_transform.js
@@ -0,0 +1,123 @@
+// 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.
+
+// a transform stream is a readable/writable stream where you do
+// something with the data. Sometimes it's called a "filter",
+// but that's not a great name for it, since that implies a thing where
+// some bits pass through, and others are simply ignored. (That would
+// be a valid example of a transform, of course.)
+//
+// While the output is causally related to the input, it's not a
+// necessarily symmetric or synchronous transformation. For example,
+// a zlib stream might take multiple plain-text writes(), and then
+// emit a single compressed chunk some time in the future.
+
+module.exports = Transform;
+
+var Duplex = require('_stream_duplex');
+var util = require('util');
+util.inherits(Transform, Duplex);
+
+function Transform(options) {
+ Duplex.call(this, options);
+
+ // bind output so that it can be passed around as a regular function.
+ this._output = this._output.bind(this);
+
+ // when the writable side finishes, then flush out anything remaining.
+ this.once('finish', function() {
+ if ('function' === typeof this._flush)
+ this._flush(this._output, done.bind(this));
+ else
+ done.call(this);
+ });
+}
+
+// This is the part where you do stuff!
+// override this function in implementation classes.
+// 'chunk' is an input chunk.
+//
+// Call `output(newChunk)` to pass along transformed output
+// to the readable side. You may call 'output' zero or more times.
+//
+// Call `cb(err)` when you are done with this chunk. If you pass
+// an error, then that'll put the hurt on the whole operation. If you
+// never call cb(), then you'll never get another chunk.
+Transform.prototype._transform = function(chunk, output, cb) {
+ throw new Error('not implemented');
+};
+
+
+Transform.prototype._write = function(chunk, cb) {
+ this._transform(chunk, this._output, cb);
+};
+
+Transform.prototype._read = function(n, cb) {
+ var ws = this._writableState;
+ var rs = this._readableState;
+
+ // basically a no-op, since the _transform will fill the
+ // _readableState.buffer and emit 'readable' for us, and set ended
+ // Usually, we want to just not call the cb, and set the reading
+ // flag to false, so that another _read will happen next time,
+ // but no state changes.
+ rs.reading = false;
+
+ // however, if the writable side has ended, and its buffer is clear,
+ // then that means that the input has all been consumed, and no more
+ // will ever be provide. treat this as an EOF, and pass back 0 bytes.
+ if ((ws.ended || ws.ending) && ws.length === 0)
+ cb();
+};
+
+Transform.prototype._output = function(chunk) {
+ if (!chunk || !chunk.length)
+ return;
+
+ var state = this._readableState;
+ var len = state.length;
+ state.buffer.push(chunk);
+ state.length += chunk.length;
+ if (state.needReadable) {
+ state.needReadable = false;
+ this.emit('readable');
+ }
+};
+
+function done(er) {
+ if (er)
+ return this.emit('error', er);
+
+ // if there's nothing in the write buffer, then that means
+ // that nothing more will ever be provided
+ var ws = this._writableState;
+ var rs = this._readableState;
+
+ rs.ended = true;
+ // we may have gotten a 'null' read before, and since there is
+ // no more data coming from the writable side, we need to emit
+ // now so that the consumer knows to pick up the tail bits.
+ if (rs.length && rs.needReadable)
+ this.emit('readable');
+ else if (rs.length === 0) {
+ this.emit('end');
+ }
+}
View
135 lib/_stream_writable.js
@@ -0,0 +1,135 @@
+// 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.
+
+// A bit simpler than readable streams.
+// Implement an async ._write(chunk, cb), and it'll handle all
+// the drain event emission and buffering.
+
+module.exports = Writable
+
+var util = require('util');
+var Stream = require('stream');
+
+util.inherits(Writable, Stream);
+
+function WritableState(options) {
+ options = options || {};
+ this.highWaterMark = options.highWaterMark || 16 * 1024;
+ this.lowWaterMark = options.lowWaterMark || 1024;
+ this.needDrain = false;
+ this.ended = false;
+ this.ending = false;
+
+ // not an actual buffer we keep track of, but a measurement
+ // of how much we're waiting to get pushed to some underlying
+ // socket or file.
+ this.length = 0;
+
+ this.writing = false;
+ this.buffer = [];
+}
+
+function Writable(options) {
+ this._writableState = new WritableState(options);
+
+ // legacy.
+ this.writable = true;
+
+ Stream.call(this);
+}
+
+// Override this method for sync streams
+// override the _write(chunk, cb) method for async streams
+Writable.prototype.write = function(chunk, encoding) {
+ var state = this._writableState;
+ if (state.ended) {
+ this.emit('error', new Error('write after end'));
+ return;
+ }
+
+ if (typeof chunk === 'string' && encoding)
+ chunk = new Buffer(chunk, encoding);
+
+ var ret = state.length >= state.highWaterMark;
+ if (ret === false)
+ state.needDrain = true;
+
+ var l = chunk.length;
+ state.length += l;
+
+ if (state.writing) {
+ state.buffer.push(chunk);
+ return ret;
+ }
+
+ state.writing = true;
+ this._write(chunk, function writecb(er) {
+ state.writing = false;
+ if (er) {
+ this.emit('error', er);
+ return;
+ }
+ state.length -= l;
+
+ if (state.length === 0 && (state.ended || state.ending)) {
+ // emit 'finish' at the very end.
+ this.emit('finish');
+ return;
+ }
+
+ // if there's something in the buffer waiting, then do that, too.
+ if (state.buffer.length) {
+ chunk = state.buffer.shift();
+ l = chunk.length;
+ state.writing = true;
+ this._write(chunk, writecb.bind(this));
+ }
+
+ if (state.length < state.lowWaterMark && state.needDrain) {
+ // Must force callback to be called on nextTick, so that we don't
+ // emit 'drain' before the write() consumer gets the 'false' return
+ // value, and has a chance to attach a 'drain' listener.
+ process.nextTick(function() {
+ if (!state.needDrain)
+ return;
+ state.needDrain = false;
+ this.emit('drain');
+ }.bind(this));
+ }
+
+ }.bind(this));
+
+ return ret;
+};
+
+Writable.prototype._write = function(chunk, cb) {
+ process.nextTick(cb.bind(this, new Error('not implemented')));
+};
+
+Writable.prototype.end = function(chunk, encoding) {
+ var state = this._writableState;
+ state.ending = true;
+ if (chunk)
+ this.write(chunk, encoding);
+ else if (state.length === 0)
+ this.emit('finish');
+ state.ended = true;
+};
View
21 lib/stream.js
@@ -19,17 +19,30 @@
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.
+module.exports = Stream;
+
var events = require('events');
var util = require('util');
-function Stream() {
- events.EventEmitter.call(this);
-}
util.inherits(Stream, events.EventEmitter);
-module.exports = Stream;
+Stream.Readable = require('_stream_readable');
+Stream.Writable = require('_stream_writable');
+Stream.Duplex = require('_stream_duplex');
+Stream.Transform = require('_stream_transform');
+Stream.PassThrough = require('_stream_passthrough');
+
// 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() {
+ events.EventEmitter.call(this);
+}
+
Stream.prototype.pipe = function(dest, options) {
var source = this;
View
5 node.gyp
@@ -44,6 +44,11 @@
'lib/readline.js',
'lib/repl.js',
'lib/stream.js',
+ 'lib/_stream_readable.js',
+ 'lib/_stream_writable.js',
+ 'lib/_stream_duplex.js',
+ 'lib/_stream_transform.js',
+ 'lib/_stream_passthrough.js',
'lib/string_decoder.js',
'lib/sys.js',
'lib/timers.js',

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