diff options
Diffstat (limited to 'node_modules/readable-stream/lib/_stream_writable.js')
-rw-r--r-- | node_modules/readable-stream/lib/_stream_writable.js | 477 |
1 files changed, 477 insertions, 0 deletions
diff --git a/node_modules/readable-stream/lib/_stream_writable.js b/node_modules/readable-stream/lib/_stream_writable.js new file mode 100644 index 000000000..db8539cd5 --- /dev/null +++ b/node_modules/readable-stream/lib/_stream_writable.js @@ -0,0 +1,477 @@ +// 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; + +/*<replacement>*/ +var Buffer = require('buffer').Buffer; +/*</replacement>*/ + +Writable.WritableState = WritableState; + + +/*<replacement>*/ +var util = require('core-util-is'); +util.inherits = require('inherits'); +/*</replacement>*/ + +var Stream = require('stream'); + +util.inherits(Writable, Stream); + +function WriteReq(chunk, encoding, cb) { + this.chunk = chunk; + this.encoding = encoding; + this.callback = cb; +} + +function WritableState(options, stream) { + var Duplex = require('./_stream_duplex'); + + options = options || {}; + + // the point at which write() starts returning false + // Note: 0 is a valid value, means that we always return false if + // the entire buffer is not flushed immediately on write() + var hwm = options.highWaterMark; + var defaultHwm = options.objectMode ? 16 : 16 * 1024; + this.highWaterMark = (hwm || hwm === 0) ? hwm : defaultHwm; + + // object stream flag to indicate whether or not this stream + // contains buffers or objects. + this.objectMode = !!options.objectMode; + + if (stream instanceof Duplex) + this.objectMode = this.objectMode || !!options.writableObjectMode; + + // cast to ints. + this.highWaterMark = ~~this.highWaterMark; + + this.needDrain = false; + // at the start of calling end() + this.ending = false; + // when end() has been called, and returned + this.ended = false; + // when 'finish' is emitted + this.finished = false; + + // should we decode strings into buffers before passing to _write? + // this is here so that some node-core streams can optimize string + // handling at a lower level. + var noDecode = options.decodeStrings === false; + this.decodeStrings = !noDecode; + + // 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'; + + // 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; + + // a flag to see when we're in the middle of a write. + this.writing = false; + + // when true all writes will be buffered until .uncork() call + this.corked = 0; + + // 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, because any + // actions that shouldn't happen until "later" should generally also + // not happen before the first write call. + this.sync = true; + + // a flag to know if we're processing previously buffered items, which + // may call the _write() callback in the same tick, so that we don't + // end up in an overlapped onwrite situation. + this.bufferProcessing = false; + + // the callback that's passed to _write(chunk,cb) + this.onwrite = function(er) { + onwrite(stream, er); + }; + + // the callback that the user supplies to write(chunk,encoding,cb) + this.writecb = null; + + // the amount that is being written when _write is called. + this.writelen = 0; + + this.buffer = []; + + // number of pending user-supplied write callbacks + // this must be 0 before 'finish' can be emitted + this.pendingcb = 0; + + // emit prefinish if the only thing we're waiting for is _write cbs + // This is relevant for synchronous Transform streams + this.prefinished = false; + + // True if the error was already emitted and should not be thrown again + this.errorEmitted = false; +} + +function Writable(options) { + var Duplex = require('./_stream_duplex'); + + // Writable ctor is applied to Duplexes, though they're not + // instanceof Writable, they're instanceof Readable. + if (!(this instanceof Writable) && !(this instanceof Duplex)) + return new Writable(options); + + this._writableState = new WritableState(options, this); + + // legacy. + this.writable = true; + + Stream.call(this); +} + +// Otherwise people can pipe Writable streams, which is just wrong. +Writable.prototype.pipe = function() { + this.emit('error', new Error('Cannot pipe. Not readable.')); +}; + + +function writeAfterEnd(stream, state, cb) { + var er = new Error('write after end'); + // TODO: defer error events consistently everywhere, not just the cb + stream.emit('error', er); + process.nextTick(function() { + cb(er); + }); +} + +// If we get something that is not a buffer, string, null, or undefined, +// and we're not in objectMode, then that's an error. +// Otherwise stream chunks are all considered to be of length=1, and the +// watermarks determine how many objects to keep in the buffer, rather than +// how many bytes or characters. +function validChunk(stream, state, chunk, cb) { + var valid = true; + if (!util.isBuffer(chunk) && + !util.isString(chunk) && + !util.isNullOrUndefined(chunk) && + !state.objectMode) { + var er = new TypeError('Invalid non-string/buffer chunk'); + stream.emit('error', er); + process.nextTick(function() { + cb(er); + }); + valid = false; + } + return valid; +} + +Writable.prototype.write = function(chunk, encoding, cb) { + var state = this._writableState; + var ret = false; + + if (util.isFunction(encoding)) { + cb = encoding; + encoding = null; + } + + if (util.isBuffer(chunk)) + encoding = 'buffer'; + else if (!encoding) + encoding = state.defaultEncoding; + + if (!util.isFunction(cb)) + cb = function() {}; + + if (state.ended) + writeAfterEnd(this, state, cb); + else if (validChunk(this, state, chunk, cb)) { + state.pendingcb++; + ret = writeOrBuffer(this, state, chunk, encoding, cb); + } + + return ret; +}; + +Writable.prototype.cork = function() { + var state = this._writableState; + + state.corked++; +}; + +Writable.prototype.uncork = function() { + var state = this._writableState; + + if (state.corked) { + state.corked--; + + if (!state.writing && + !state.corked && + !state.finished && + !state.bufferProcessing && + state.buffer.length) + clearBuffer(this, state); + } +}; + +function decodeChunk(state, chunk, encoding) { + if (!state.objectMode && + state.decodeStrings !== false && + util.isString(chunk)) { + chunk = new Buffer(chunk, encoding); + } + return chunk; +} + +// if we're already writing something, then just put this +// in the queue, and wait our turn. Otherwise, call _write +// If we return false, then we need a drain event, so set that flag. +function writeOrBuffer(stream, state, chunk, encoding, cb) { + chunk = decodeChunk(state, chunk, encoding); + if (util.isBuffer(chunk)) + encoding = 'buffer'; + var len = state.objectMode ? 1 : chunk.length; + + state.length += len; + + var ret = state.length < state.highWaterMark; + // we must ensure that previous needDrain will not be reset to false. + if (!ret) + state.needDrain = true; + + if (state.writing || state.corked) + state.buffer.push(new WriteReq(chunk, encoding, cb)); + else + doWrite(stream, state, false, len, chunk, encoding, cb); + + return ret; +} + +function doWrite(stream, state, writev, len, chunk, encoding, cb) { + state.writelen = len; + state.writecb = cb; + state.writing = true; + state.sync = true; + if (writev) + stream._writev(chunk, state.onwrite); + else + stream._write(chunk, encoding, state.onwrite); + state.sync = false; +} + +function onwriteError(stream, state, sync, er, cb) { + if (sync) + process.nextTick(function() { + state.pendingcb--; + cb(er); + }); + else { + state.pendingcb--; + cb(er); + } + + stream._writableState.errorEmitted = true; + stream.emit('error', er); +} + +function onwriteStateUpdate(state) { + state.writing = false; + state.writecb = null; + state.length -= state.writelen; + state.writelen = 0; +} + +function onwrite(stream, er) { + var state = stream._writableState; + var sync = state.sync; + var cb = state.writecb; + + onwriteStateUpdate(state); + + if (er) + onwriteError(stream, state, sync, er, cb); + else { + // Check if we're actually ready to finish, but don't emit yet + var finished = needFinish(stream, state); + + if (!finished && + !state.corked && + !state.bufferProcessing && + state.buffer.length) { + clearBuffer(stream, state); + } + + if (sync) { + process.nextTick(function() { + afterWrite(stream, state, finished, cb); + }); + } else { + afterWrite(stream, state, finished, cb); + } + } +} + +function afterWrite(stream, state, finished, cb) { + if (!finished) + onwriteDrain(stream, state); + state.pendingcb--; + cb(); + finishMaybe(stream, state); +} + +// 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. +function onwriteDrain(stream, state) { + if (state.length === 0 && state.needDrain) { + state.needDrain = false; + stream.emit('drain'); + } +} + + +// if there's something in the buffer waiting, then process it +function clearBuffer(stream, state) { + state.bufferProcessing = true; + + if (stream._writev && state.buffer.length > 1) { + // Fast case, write everything using _writev() + var cbs = []; + for (var c = 0; c < state.buffer.length; c++) + cbs.push(state.buffer[c].callback); + + // count the one we are adding, as well. + // TODO(isaacs) clean this up + state.pendingcb++; + doWrite(stream, state, true, state.length, state.buffer, '', function(err) { + for (var i = 0; i < cbs.length; i++) { + state.pendingcb--; + cbs[i](err); + } + }); + + // Clear buffer + state.buffer = []; + } else { + // Slow case, write chunks one-by-one + for (var c = 0; c < state.buffer.length; c++) { + var entry = state.buffer[c]; + var chunk = entry.chunk; + var encoding = entry.encoding; + var cb = entry.callback; + var len = state.objectMode ? 1 : chunk.length; + + doWrite(stream, state, false, len, chunk, encoding, cb); + + // if we didn't call the onwrite immediately, then + // it means that we need to wait until it does. + // also, that means that the chunk and cb are currently + // being processed, so move the buffer counter past them. + if (state.writing) { + c++; + break; + } + } + + if (c < state.buffer.length) + state.buffer = state.buffer.slice(c); + else + state.buffer.length = 0; + } + + state.bufferProcessing = false; +} + +Writable.prototype._write = function(chunk, encoding, cb) { + cb(new Error('not implemented')); + +}; + +Writable.prototype._writev = null; + +Writable.prototype.end = function(chunk, encoding, cb) { + var state = this._writableState; + + if (util.isFunction(chunk)) { + cb = chunk; + chunk = null; + encoding = null; + } else if (util.isFunction(encoding)) { + cb = encoding; + encoding = null; + } + + if (!util.isNullOrUndefined(chunk)) + this.write(chunk, encoding); + + // .end() fully uncorks + if (state.corked) { + state.corked = 1; + this.uncork(); + } + + // ignore unnecessary end() calls. + if (!state.ending && !state.finished) + endWritable(this, state, cb); +}; + + +function needFinish(stream, state) { + return (state.ending && + state.length === 0 && + !state.finished && + !state.writing); +} + +function prefinish(stream, state) { + if (!state.prefinished) { + state.prefinished = true; + stream.emit('prefinish'); + } +} + +function finishMaybe(stream, state) { + var need = needFinish(stream, state); + if (need) { + if (state.pendingcb === 0) { + prefinish(stream, state); + state.finished = true; + stream.emit('finish'); + } else + prefinish(stream, state); + } + return need; +} + +function endWritable(stream, state, cb) { + state.ending = true; + finishMaybe(stream, state); + if (cb) { + if (state.finished) + process.nextTick(cb); + else + stream.once('finish', cb); + } + state.ended = true; +} |