// Copyright Joyent, Inc. and other Node contributors.
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//
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// Permission is hereby granted, free of charge, to any person obtaining a
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// copy of this software and associated documentation files (the
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// "Software"), to deal in the Software without restriction, including
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// without limitation the rights to use, copy, modify, merge, publish,
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// distribute, sublicense, and/or sell copies of the Software, and to permit
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// persons to whom the Software is furnished to do so, subject to the
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// following conditions:
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//
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// The above copyright notice and this permission notice shall be included
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// in all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
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// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
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// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
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// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
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// USE OR OTHER DEALINGS IN THE SOFTWARE.
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// A bit simpler than readable streams.
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// Implement an async ._write(chunk, encoding, cb), and it'll handle all
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// the drain event emission and buffering.
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'use strict';
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module.exports = Writable;
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/* <replacement> */
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function WriteReq(chunk, encoding, cb) {
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this.chunk = chunk;
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this.encoding = encoding;
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this.callback = cb;
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this.next = null;
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} // It seems a linked list but it is not
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// there will be only 2 of these for each stream
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function CorkedRequest(state) {
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var _this = this;
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this.next = null;
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this.entry = null;
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this.finish = function () {
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onCorkedFinish(_this, state);
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};
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}
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/* </replacement> */
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/*<replacement>*/
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var Duplex;
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/*</replacement>*/
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Writable.WritableState = WritableState;
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/*<replacement>*/
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var internalUtil = {
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deprecate: require('util-deprecate')
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};
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/*</replacement>*/
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/*<replacement>*/
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var Stream = require('./internal/streams/stream');
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/*</replacement>*/
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var Buffer = require('buffer').Buffer;
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var OurUint8Array = global.Uint8Array || function () {};
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function _uint8ArrayToBuffer(chunk) {
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return Buffer.from(chunk);
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}
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function _isUint8Array(obj) {
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return Buffer.isBuffer(obj) || obj instanceof OurUint8Array;
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}
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var destroyImpl = require('./internal/streams/destroy');
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var _require = require('./internal/streams/state'),
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getHighWaterMark = _require.getHighWaterMark;
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var _require$codes = require('../errors').codes,
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ERR_INVALID_ARG_TYPE = _require$codes.ERR_INVALID_ARG_TYPE,
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ERR_METHOD_NOT_IMPLEMENTED = _require$codes.ERR_METHOD_NOT_IMPLEMENTED,
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ERR_MULTIPLE_CALLBACK = _require$codes.ERR_MULTIPLE_CALLBACK,
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ERR_STREAM_CANNOT_PIPE = _require$codes.ERR_STREAM_CANNOT_PIPE,
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ERR_STREAM_DESTROYED = _require$codes.ERR_STREAM_DESTROYED,
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ERR_STREAM_NULL_VALUES = _require$codes.ERR_STREAM_NULL_VALUES,
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ERR_STREAM_WRITE_AFTER_END = _require$codes.ERR_STREAM_WRITE_AFTER_END,
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ERR_UNKNOWN_ENCODING = _require$codes.ERR_UNKNOWN_ENCODING;
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var errorOrDestroy = destroyImpl.errorOrDestroy;
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require('inherits')(Writable, Stream);
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function nop() {}
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function WritableState(options, stream, isDuplex) {
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Duplex = Duplex || require('./_stream_duplex');
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options = options || {}; // Duplex streams are both readable and writable, but share
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// the same options object.
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// However, some cases require setting options to different
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// values for the readable and the writable sides of the duplex stream,
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// e.g. options.readableObjectMode vs. options.writableObjectMode, etc.
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if (typeof isDuplex !== 'boolean') isDuplex = stream instanceof Duplex; // object stream flag to indicate whether or not this stream
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// contains buffers or objects.
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this.objectMode = !!options.objectMode;
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if (isDuplex) this.objectMode = this.objectMode || !!options.writableObjectMode; // the point at which write() starts returning false
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// Note: 0 is a valid value, means that we always return false if
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// the entire buffer is not flushed immediately on write()
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this.highWaterMark = getHighWaterMark(this, options, 'writableHighWaterMark', isDuplex); // if _final has been called
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this.finalCalled = false; // drain event flag.
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this.needDrain = false; // at the start of calling end()
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this.ending = false; // when end() has been called, and returned
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this.ended = false; // when 'finish' is emitted
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this.finished = false; // has it been destroyed
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this.destroyed = false; // should we decode strings into buffers before passing to _write?
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// this is here so that some node-core streams can optimize string
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// handling at a lower level.
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var noDecode = options.decodeStrings === false;
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this.decodeStrings = !noDecode; // Crypto is kind of old and crusty. Historically, its default string
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// encoding is 'binary' so we have to make this configurable.
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// Everything else in the universe uses 'utf8', though.
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this.defaultEncoding = options.defaultEncoding || 'utf8'; // not an actual buffer we keep track of, but a measurement
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// of how much we're waiting to get pushed to some underlying
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// socket or file.
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this.length = 0; // a flag to see when we're in the middle of a write.
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this.writing = false; // when true all writes will be buffered until .uncork() call
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this.corked = 0; // a flag to be able to tell if the onwrite cb is called immediately,
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// or on a later tick. We set this to true at first, because any
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// actions that shouldn't happen until "later" should generally also
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// not happen before the first write call.
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this.sync = true; // a flag to know if we're processing previously buffered items, which
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// may call the _write() callback in the same tick, so that we don't
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// end up in an overlapped onwrite situation.
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this.bufferProcessing = false; // the callback that's passed to _write(chunk,cb)
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this.onwrite = function (er) {
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onwrite(stream, er);
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}; // the callback that the user supplies to write(chunk,encoding,cb)
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this.writecb = null; // the amount that is being written when _write is called.
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this.writelen = 0;
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this.bufferedRequest = null;
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this.lastBufferedRequest = null; // number of pending user-supplied write callbacks
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// this must be 0 before 'finish' can be emitted
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this.pendingcb = 0; // emit prefinish if the only thing we're waiting for is _write cbs
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// This is relevant for synchronous Transform streams
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this.prefinished = false; // True if the error was already emitted and should not be thrown again
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this.errorEmitted = false; // Should close be emitted on destroy. Defaults to true.
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this.emitClose = options.emitClose !== false; // Should .destroy() be called after 'finish' (and potentially 'end')
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this.autoDestroy = !!options.autoDestroy; // count buffered requests
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this.bufferedRequestCount = 0; // allocate the first CorkedRequest, there is always
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// one allocated and free to use, and we maintain at most two
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this.corkedRequestsFree = new CorkedRequest(this);
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}
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WritableState.prototype.getBuffer = function getBuffer() {
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var current = this.bufferedRequest;
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var out = [];
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while (current) {
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out.push(current);
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current = current.next;
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}
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return out;
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};
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(function () {
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try {
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Object.defineProperty(WritableState.prototype, 'buffer', {
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get: internalUtil.deprecate(function writableStateBufferGetter() {
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return this.getBuffer();
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}, '_writableState.buffer is deprecated. Use _writableState.getBuffer ' + 'instead.', 'DEP0003')
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});
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} catch (_) {}
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})(); // Test _writableState for inheritance to account for Duplex streams,
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// whose prototype chain only points to Readable.
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var realHasInstance;
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if (typeof Symbol === 'function' && Symbol.hasInstance && typeof Function.prototype[Symbol.hasInstance] === 'function') {
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realHasInstance = Function.prototype[Symbol.hasInstance];
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Object.defineProperty(Writable, Symbol.hasInstance, {
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value: function value(object) {
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if (realHasInstance.call(this, object)) return true;
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if (this !== Writable) return false;
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return object && object._writableState instanceof WritableState;
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}
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});
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} else {
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realHasInstance = function realHasInstance(object) {
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return object instanceof this;
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};
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}
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function Writable(options) {
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Duplex = Duplex || require('./_stream_duplex'); // Writable ctor is applied to Duplexes, too.
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// `realHasInstance` is necessary because using plain `instanceof`
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// would return false, as no `_writableState` property is attached.
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// Trying to use the custom `instanceof` for Writable here will also break the
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// Node.js LazyTransform implementation, which has a non-trivial getter for
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// `_writableState` that would lead to infinite recursion.
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// Checking for a Stream.Duplex instance is faster here instead of inside
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// the WritableState constructor, at least with V8 6.5
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var isDuplex = this instanceof Duplex;
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if (!isDuplex && !realHasInstance.call(Writable, this)) return new Writable(options);
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this._writableState = new WritableState(options, this, isDuplex); // legacy.
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this.writable = true;
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if (options) {
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if (typeof options.write === 'function') this._write = options.write;
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if (typeof options.writev === 'function') this._writev = options.writev;
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if (typeof options.destroy === 'function') this._destroy = options.destroy;
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if (typeof options.final === 'function') this._final = options.final;
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}
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Stream.call(this);
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} // Otherwise people can pipe Writable streams, which is just wrong.
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Writable.prototype.pipe = function () {
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errorOrDestroy(this, new ERR_STREAM_CANNOT_PIPE());
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};
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function writeAfterEnd(stream, cb) {
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var er = new ERR_STREAM_WRITE_AFTER_END(); // TODO: defer error events consistently everywhere, not just the cb
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errorOrDestroy(stream, er);
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process.nextTick(cb, er);
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} // Checks that a user-supplied chunk is valid, especially for the particular
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// mode the stream is in. Currently this means that `null` is never accepted
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// and undefined/non-string values are only allowed in object mode.
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function validChunk(stream, state, chunk, cb) {
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var er;
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if (chunk === null) {
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er = new ERR_STREAM_NULL_VALUES();
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} else if (typeof chunk !== 'string' && !state.objectMode) {
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er = new ERR_INVALID_ARG_TYPE('chunk', ['string', 'Buffer'], chunk);
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}
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if (er) {
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errorOrDestroy(stream, er);
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process.nextTick(cb, er);
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return false;
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}
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return true;
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}
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Writable.prototype.write = function (chunk, encoding, cb) {
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var state = this._writableState;
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var ret = false;
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var isBuf = !state.objectMode && _isUint8Array(chunk);
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if (isBuf && !Buffer.isBuffer(chunk)) {
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chunk = _uint8ArrayToBuffer(chunk);
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}
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if (typeof encoding === 'function') {
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cb = encoding;
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encoding = null;
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}
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if (isBuf) encoding = 'buffer';else if (!encoding) encoding = state.defaultEncoding;
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if (typeof cb !== 'function') cb = nop;
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if (state.ending) writeAfterEnd(this, cb);else if (isBuf || validChunk(this, state, chunk, cb)) {
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state.pendingcb++;
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ret = writeOrBuffer(this, state, isBuf, chunk, encoding, cb);
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}
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return ret;
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};
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Writable.prototype.cork = function () {
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this._writableState.corked++;
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};
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Writable.prototype.uncork = function () {
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var state = this._writableState;
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if (state.corked) {
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state.corked--;
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if (!state.writing && !state.corked && !state.bufferProcessing && state.bufferedRequest) clearBuffer(this, state);
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}
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};
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Writable.prototype.setDefaultEncoding = function setDefaultEncoding(encoding) {
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// node::ParseEncoding() requires lower case.
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if (typeof encoding === 'string') encoding = encoding.toLowerCase();
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if (!(['hex', 'utf8', 'utf-8', 'ascii', 'binary', 'base64', 'ucs2', 'ucs-2', 'utf16le', 'utf-16le', 'raw'].indexOf((encoding + '').toLowerCase()) > -1)) throw new ERR_UNKNOWN_ENCODING(encoding);
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this._writableState.defaultEncoding = encoding;
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return this;
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};
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Object.defineProperty(Writable.prototype, 'writableBuffer', {
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// making it explicit this property is not enumerable
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// because otherwise some prototype manipulation in
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// userland will fail
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enumerable: false,
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get: function get() {
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return this._writableState && this._writableState.getBuffer();
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}
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});
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function decodeChunk(state, chunk, encoding) {
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if (!state.objectMode && state.decodeStrings !== false && typeof chunk === 'string') {
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chunk = Buffer.from(chunk, encoding);
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}
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return chunk;
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}
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Object.defineProperty(Writable.prototype, 'writableHighWaterMark', {
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// making it explicit this property is not enumerable
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// because otherwise some prototype manipulation in
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// userland will fail
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enumerable: false,
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get: function get() {
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return this._writableState.highWaterMark;
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}
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}); // if we're already writing something, then just put this
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// in the queue, and wait our turn. Otherwise, call _write
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// If we return false, then we need a drain event, so set that flag.
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function writeOrBuffer(stream, state, isBuf, chunk, encoding, cb) {
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if (!isBuf) {
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var newChunk = decodeChunk(state, chunk, encoding);
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if (chunk !== newChunk) {
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isBuf = true;
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encoding = 'buffer';
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chunk = newChunk;
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}
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}
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var len = state.objectMode ? 1 : chunk.length;
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state.length += len;
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var ret = state.length < state.highWaterMark; // we must ensure that previous needDrain will not be reset to false.
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if (!ret) state.needDrain = true;
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if (state.writing || state.corked) {
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var last = state.lastBufferedRequest;
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state.lastBufferedRequest = {
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chunk: chunk,
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encoding: encoding,
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isBuf: isBuf,
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callback: cb,
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next: null
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};
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if (last) {
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last.next = state.lastBufferedRequest;
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} else {
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state.bufferedRequest = state.lastBufferedRequest;
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}
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state.bufferedRequestCount += 1;
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} else {
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doWrite(stream, state, false, len, chunk, encoding, cb);
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}
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return ret;
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}
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function doWrite(stream, state, writev, len, chunk, encoding, cb) {
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state.writelen = len;
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state.writecb = cb;
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state.writing = true;
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state.sync = true;
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if (state.destroyed) state.onwrite(new ERR_STREAM_DESTROYED('write'));else if (writev) stream._writev(chunk, state.onwrite);else stream._write(chunk, encoding, state.onwrite);
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state.sync = false;
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}
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function onwriteError(stream, state, sync, er, cb) {
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--state.pendingcb;
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if (sync) {
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// defer the callback if we are being called synchronously
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// to avoid piling up things on the stack
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process.nextTick(cb, er); // this can emit finish, and it will always happen
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// after error
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process.nextTick(finishMaybe, stream, state);
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stream._writableState.errorEmitted = true;
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errorOrDestroy(stream, er);
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} else {
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// the caller expect this to happen before if
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// it is async
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cb(er);
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stream._writableState.errorEmitted = true;
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errorOrDestroy(stream, er); // this can emit finish, but finish must
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// always follow error
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finishMaybe(stream, state);
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}
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}
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function onwriteStateUpdate(state) {
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state.writing = false;
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state.writecb = null;
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state.length -= state.writelen;
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state.writelen = 0;
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}
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function onwrite(stream, er) {
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var state = stream._writableState;
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var sync = state.sync;
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var cb = state.writecb;
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if (typeof cb !== 'function') throw new ERR_MULTIPLE_CALLBACK();
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onwriteStateUpdate(state);
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if (er) onwriteError(stream, state, sync, er, cb);else {
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// Check if we're actually ready to finish, but don't emit yet
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var finished = needFinish(state) || stream.destroyed;
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if (!finished && !state.corked && !state.bufferProcessing && state.bufferedRequest) {
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clearBuffer(stream, state);
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}
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if (sync) {
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process.nextTick(afterWrite, stream, state, finished, cb);
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} else {
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afterWrite(stream, state, finished, cb);
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}
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}
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}
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function afterWrite(stream, state, finished, cb) {
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if (!finished) onwriteDrain(stream, state);
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state.pendingcb--;
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cb();
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finishMaybe(stream, state);
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} // Must force callback to be called on nextTick, so that we don't
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// emit 'drain' before the write() consumer gets the 'false' return
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// value, and has a chance to attach a 'drain' listener.
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function onwriteDrain(stream, state) {
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if (state.length === 0 && state.needDrain) {
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state.needDrain = false;
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stream.emit('drain');
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}
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} // if there's something in the buffer waiting, then process it
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function clearBuffer(stream, state) {
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state.bufferProcessing = true;
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var entry = state.bufferedRequest;
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if (stream._writev && entry && entry.next) {
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// Fast case, write everything using _writev()
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var l = state.bufferedRequestCount;
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var buffer = new Array(l);
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var holder = state.corkedRequestsFree;
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holder.entry = entry;
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var count = 0;
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var allBuffers = true;
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while (entry) {
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buffer[count] = entry;
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if (!entry.isBuf) allBuffers = false;
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entry = entry.next;
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count += 1;
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}
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buffer.allBuffers = allBuffers;
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doWrite(stream, state, true, state.length, buffer, '', holder.finish); // doWrite is almost always async, defer these to save a bit of time
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// as the hot path ends with doWrite
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state.pendingcb++;
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state.lastBufferedRequest = null;
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if (holder.next) {
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state.corkedRequestsFree = holder.next;
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holder.next = null;
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} else {
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state.corkedRequestsFree = new CorkedRequest(state);
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}
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state.bufferedRequestCount = 0;
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} else {
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// Slow case, write chunks one-by-one
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while (entry) {
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var chunk = entry.chunk;
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var encoding = entry.encoding;
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var cb = entry.callback;
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var len = state.objectMode ? 1 : chunk.length;
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doWrite(stream, state, false, len, chunk, encoding, cb);
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entry = entry.next;
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state.bufferedRequestCount--; // if we didn't call the onwrite immediately, then
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// it means that we need to wait until it does.
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// also, that means that the chunk and cb are currently
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// being processed, so move the buffer counter past them.
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if (state.writing) {
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break;
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}
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}
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if (entry === null) state.lastBufferedRequest = null;
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}
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state.bufferedRequest = entry;
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state.bufferProcessing = false;
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}
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Writable.prototype._write = function (chunk, encoding, cb) {
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cb(new ERR_METHOD_NOT_IMPLEMENTED('_write()'));
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};
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Writable.prototype._writev = null;
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Writable.prototype.end = function (chunk, encoding, cb) {
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var state = this._writableState;
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if (typeof chunk === 'function') {
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cb = chunk;
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chunk = null;
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encoding = null;
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} else if (typeof encoding === 'function') {
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cb = encoding;
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encoding = null;
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}
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if (chunk !== null && chunk !== undefined) this.write(chunk, encoding); // .end() fully uncorks
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if (state.corked) {
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state.corked = 1;
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this.uncork();
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} // ignore unnecessary end() calls.
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if (!state.ending) endWritable(this, state, cb);
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return this;
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};
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Object.defineProperty(Writable.prototype, 'writableLength', {
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// making it explicit this property is not enumerable
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// because otherwise some prototype manipulation in
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// userland will fail
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enumerable: false,
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get: function get() {
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return this._writableState.length;
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}
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});
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function needFinish(state) {
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return state.ending && state.length === 0 && state.bufferedRequest === null && !state.finished && !state.writing;
|
}
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function callFinal(stream, state) {
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stream._final(function (err) {
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state.pendingcb--;
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if (err) {
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errorOrDestroy(stream, err);
|
}
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state.prefinished = true;
|
stream.emit('prefinish');
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finishMaybe(stream, state);
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});
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}
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function prefinish(stream, state) {
|
if (!state.prefinished && !state.finalCalled) {
|
if (typeof stream._final === 'function' && !state.destroyed) {
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state.pendingcb++;
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state.finalCalled = true;
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process.nextTick(callFinal, stream, state);
|
} else {
|
state.prefinished = true;
|
stream.emit('prefinish');
|
}
|
}
|
}
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function finishMaybe(stream, state) {
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var need = needFinish(state);
|
|
if (need) {
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prefinish(stream, state);
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|
if (state.pendingcb === 0) {
|
state.finished = true;
|
stream.emit('finish');
|
|
if (state.autoDestroy) {
|
// In case of duplex streams we need a way to detect
|
// if the readable side is ready for autoDestroy as well
|
var rState = stream._readableState;
|
|
if (!rState || rState.autoDestroy && rState.endEmitted) {
|
stream.destroy();
|
}
|
}
|
}
|
}
|
|
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;
|
stream.writable = false;
|
}
|
|
function onCorkedFinish(corkReq, state, err) {
|
var entry = corkReq.entry;
|
corkReq.entry = null;
|
|
while (entry) {
|
var cb = entry.callback;
|
state.pendingcb--;
|
cb(err);
|
entry = entry.next;
|
} // reuse the free corkReq.
|
|
|
state.corkedRequestsFree.next = corkReq;
|
}
|
|
Object.defineProperty(Writable.prototype, 'destroyed', {
|
// making it explicit this property is not enumerable
|
// because otherwise some prototype manipulation in
|
// userland will fail
|
enumerable: false,
|
get: function get() {
|
if (this._writableState === undefined) {
|
return false;
|
}
|
|
return this._writableState.destroyed;
|
},
|
set: function set(value) {
|
// we ignore the value if the stream
|
// has not been initialized yet
|
if (!this._writableState) {
|
return;
|
} // backward compatibility, the user is explicitly
|
// managing destroyed
|
|
|
this._writableState.destroyed = value;
|
}
|
});
|
Writable.prototype.destroy = destroyImpl.destroy;
|
Writable.prototype._undestroy = destroyImpl.undestroy;
|
|
Writable.prototype._destroy = function (err, cb) {
|
cb(err);
|
};
|
