1// Copyright Joyent, Inc. and other Node contributors. 2// 3// Permission is hereby granted, free of charge, to any person obtaining a 4// copy of this software and associated documentation files (the 5// "Software"), to deal in the Software without restriction, including 6// without limitation the rights to use, copy, modify, merge, publish, 7// distribute, sublicense, and/or sell copies of the Software, and to permit 8// persons to whom the Software is furnished to do so, subject to the 9// following conditions: 10// 11// The above copyright notice and this permission notice shall be included 12// in all copies or substantial portions of the Software. 13// 14// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS 15// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 16// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN 17// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, 18// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR 19// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE 20// USE OR OTHER DEALINGS IN THE SOFTWARE. 21// A bit simpler than readable streams. 22// Implement an async ._write(chunk, encoding, cb), and it'll handle all 23// the drain event emission and buffering. 24'use strict'; 25 26module.exports = Writable; 27/* <replacement> */ 28 29function WriteReq(chunk, encoding, cb) { 30 this.chunk = chunk; 31 this.encoding = encoding; 32 this.callback = cb; 33 this.next = null; 34} // It seems a linked list but it is not 35// there will be only 2 of these for each stream 36 37 38function CorkedRequest(state) { 39 var _this = this; 40 41 this.next = null; 42 this.entry = null; 43 44 this.finish = function () { 45 onCorkedFinish(_this, state); 46 }; 47} 48/* </replacement> */ 49 50/*<replacement>*/ 51 52 53var Duplex; 54/*</replacement>*/ 55 56Writable.WritableState = WritableState; 57/*<replacement>*/ 58 59var internalUtil = { 60 deprecate: require('util-deprecate') 61}; 62/*</replacement>*/ 63 64/*<replacement>*/ 65 66var Stream = require('./internal/streams/stream'); 67/*</replacement>*/ 68 69 70var Buffer = require('buffer').Buffer; 71 72var OurUint8Array = global.Uint8Array || function () {}; 73 74function _uint8ArrayToBuffer(chunk) { 75 return Buffer.from(chunk); 76} 77 78function _isUint8Array(obj) { 79 return Buffer.isBuffer(obj) || obj instanceof OurUint8Array; 80} 81 82var destroyImpl = require('./internal/streams/destroy'); 83 84var _require = require('./internal/streams/state'), 85 getHighWaterMark = _require.getHighWaterMark; 86 87var _require$codes = require('../errors').codes, 88 ERR_INVALID_ARG_TYPE = _require$codes.ERR_INVALID_ARG_TYPE, 89 ERR_METHOD_NOT_IMPLEMENTED = _require$codes.ERR_METHOD_NOT_IMPLEMENTED, 90 ERR_MULTIPLE_CALLBACK = _require$codes.ERR_MULTIPLE_CALLBACK, 91 ERR_STREAM_CANNOT_PIPE = _require$codes.ERR_STREAM_CANNOT_PIPE, 92 ERR_STREAM_DESTROYED = _require$codes.ERR_STREAM_DESTROYED, 93 ERR_STREAM_NULL_VALUES = _require$codes.ERR_STREAM_NULL_VALUES, 94 ERR_STREAM_WRITE_AFTER_END = _require$codes.ERR_STREAM_WRITE_AFTER_END, 95 ERR_UNKNOWN_ENCODING = _require$codes.ERR_UNKNOWN_ENCODING; 96 97var errorOrDestroy = destroyImpl.errorOrDestroy; 98 99require('inherits')(Writable, Stream); 100 101function nop() {} 102 103function WritableState(options, stream, isDuplex) { 104 Duplex = Duplex || require('./_stream_duplex'); 105 options = options || {}; // Duplex streams are both readable and writable, but share 106 // the same options object. 107 // However, some cases require setting options to different 108 // values for the readable and the writable sides of the duplex stream, 109 // e.g. options.readableObjectMode vs. options.writableObjectMode, etc. 110 111 if (typeof isDuplex !== 'boolean') isDuplex = stream instanceof Duplex; // object stream flag to indicate whether or not this stream 112 // contains buffers or objects. 113 114 this.objectMode = !!options.objectMode; 115 if (isDuplex) this.objectMode = this.objectMode || !!options.writableObjectMode; // the point at which write() starts returning false 116 // Note: 0 is a valid value, means that we always return false if 117 // the entire buffer is not flushed immediately on write() 118 119 this.highWaterMark = getHighWaterMark(this, options, 'writableHighWaterMark', isDuplex); // if _final has been called 120 121 this.finalCalled = false; // drain event flag. 122 123 this.needDrain = false; // at the start of calling end() 124 125 this.ending = false; // when end() has been called, and returned 126 127 this.ended = false; // when 'finish' is emitted 128 129 this.finished = false; // has it been destroyed 130 131 this.destroyed = false; // should we decode strings into buffers before passing to _write? 132 // this is here so that some node-core streams can optimize string 133 // handling at a lower level. 134 135 var noDecode = options.decodeStrings === false; 136 this.decodeStrings = !noDecode; // Crypto is kind of old and crusty. Historically, its default string 137 // encoding is 'binary' so we have to make this configurable. 138 // Everything else in the universe uses 'utf8', though. 139 140 this.defaultEncoding = options.defaultEncoding || 'utf8'; // not an actual buffer we keep track of, but a measurement 141 // of how much we're waiting to get pushed to some underlying 142 // socket or file. 143 144 this.length = 0; // a flag to see when we're in the middle of a write. 145 146 this.writing = false; // when true all writes will be buffered until .uncork() call 147 148 this.corked = 0; // a flag to be able to tell if the onwrite cb is called immediately, 149 // or on a later tick. We set this to true at first, because any 150 // actions that shouldn't happen until "later" should generally also 151 // not happen before the first write call. 152 153 this.sync = true; // a flag to know if we're processing previously buffered items, which 154 // may call the _write() callback in the same tick, so that we don't 155 // end up in an overlapped onwrite situation. 156 157 this.bufferProcessing = false; // the callback that's passed to _write(chunk,cb) 158 159 this.onwrite = function (er) { 160 onwrite(stream, er); 161 }; // the callback that the user supplies to write(chunk,encoding,cb) 162 163 164 this.writecb = null; // the amount that is being written when _write is called. 165 166 this.writelen = 0; 167 this.bufferedRequest = null; 168 this.lastBufferedRequest = null; // number of pending user-supplied write callbacks 169 // this must be 0 before 'finish' can be emitted 170 171 this.pendingcb = 0; // emit prefinish if the only thing we're waiting for is _write cbs 172 // This is relevant for synchronous Transform streams 173 174 this.prefinished = false; // True if the error was already emitted and should not be thrown again 175 176 this.errorEmitted = false; // Should close be emitted on destroy. Defaults to true. 177 178 this.emitClose = options.emitClose !== false; // Should .destroy() be called after 'finish' (and potentially 'end') 179 180 this.autoDestroy = !!options.autoDestroy; // count buffered requests 181 182 this.bufferedRequestCount = 0; // allocate the first CorkedRequest, there is always 183 // one allocated and free to use, and we maintain at most two 184 185 this.corkedRequestsFree = new CorkedRequest(this); 186} 187 188WritableState.prototype.getBuffer = function getBuffer() { 189 var current = this.bufferedRequest; 190 var out = []; 191 192 while (current) { 193 out.push(current); 194 current = current.next; 195 } 196 197 return out; 198}; 199 200(function () { 201 try { 202 Object.defineProperty(WritableState.prototype, 'buffer', { 203 get: internalUtil.deprecate(function writableStateBufferGetter() { 204 return this.getBuffer(); 205 }, '_writableState.buffer is deprecated. Use _writableState.getBuffer ' + 'instead.', 'DEP0003') 206 }); 207 } catch (_) {} 208})(); // Test _writableState for inheritance to account for Duplex streams, 209// whose prototype chain only points to Readable. 210 211 212var realHasInstance; 213 214if (typeof Symbol === 'function' && Symbol.hasInstance && typeof Function.prototype[Symbol.hasInstance] === 'function') { 215 realHasInstance = Function.prototype[Symbol.hasInstance]; 216 Object.defineProperty(Writable, Symbol.hasInstance, { 217 value: function value(object) { 218 if (realHasInstance.call(this, object)) return true; 219 if (this !== Writable) return false; 220 return object && object._writableState instanceof WritableState; 221 } 222 }); 223} else { 224 realHasInstance = function realHasInstance(object) { 225 return object instanceof this; 226 }; 227} 228 229function Writable(options) { 230 Duplex = Duplex || require('./_stream_duplex'); // Writable ctor is applied to Duplexes, too. 231 // `realHasInstance` is necessary because using plain `instanceof` 232 // would return false, as no `_writableState` property is attached. 233 // Trying to use the custom `instanceof` for Writable here will also break the 234 // Node.js LazyTransform implementation, which has a non-trivial getter for 235 // `_writableState` that would lead to infinite recursion. 236 // Checking for a Stream.Duplex instance is faster here instead of inside 237 // the WritableState constructor, at least with V8 6.5 238 239 var isDuplex = this instanceof Duplex; 240 if (!isDuplex && !realHasInstance.call(Writable, this)) return new Writable(options); 241 this._writableState = new WritableState(options, this, isDuplex); // legacy. 242 243 this.writable = true; 244 245 if (options) { 246 if (typeof options.write === 'function') this._write = options.write; 247 if (typeof options.writev === 'function') this._writev = options.writev; 248 if (typeof options.destroy === 'function') this._destroy = options.destroy; 249 if (typeof options.final === 'function') this._final = options.final; 250 } 251 252 Stream.call(this); 253} // Otherwise people can pipe Writable streams, which is just wrong. 254 255 256Writable.prototype.pipe = function () { 257 errorOrDestroy(this, new ERR_STREAM_CANNOT_PIPE()); 258}; 259 260function writeAfterEnd(stream, cb) { 261 var er = new ERR_STREAM_WRITE_AFTER_END(); // TODO: defer error events consistently everywhere, not just the cb 262 263 errorOrDestroy(stream, er); 264 process.nextTick(cb, er); 265} // Checks that a user-supplied chunk is valid, especially for the particular 266// mode the stream is in. Currently this means that `null` is never accepted 267// and undefined/non-string values are only allowed in object mode. 268 269 270function validChunk(stream, state, chunk, cb) { 271 var er; 272 273 if (chunk === null) { 274 er = new ERR_STREAM_NULL_VALUES(); 275 } else if (typeof chunk !== 'string' && !state.objectMode) { 276 er = new ERR_INVALID_ARG_TYPE('chunk', ['string', 'Buffer'], chunk); 277 } 278 279 if (er) { 280 errorOrDestroy(stream, er); 281 process.nextTick(cb, er); 282 return false; 283 } 284 285 return true; 286} 287 288Writable.prototype.write = function (chunk, encoding, cb) { 289 var state = this._writableState; 290 var ret = false; 291 292 var isBuf = !state.objectMode && _isUint8Array(chunk); 293 294 if (isBuf && !Buffer.isBuffer(chunk)) { 295 chunk = _uint8ArrayToBuffer(chunk); 296 } 297 298 if (typeof encoding === 'function') { 299 cb = encoding; 300 encoding = null; 301 } 302 303 if (isBuf) encoding = 'buffer';else if (!encoding) encoding = state.defaultEncoding; 304 if (typeof cb !== 'function') cb = nop; 305 if (state.ending) writeAfterEnd(this, cb);else if (isBuf || validChunk(this, state, chunk, cb)) { 306 state.pendingcb++; 307 ret = writeOrBuffer(this, state, isBuf, chunk, encoding, cb); 308 } 309 return ret; 310}; 311 312Writable.prototype.cork = function () { 313 this._writableState.corked++; 314}; 315 316Writable.prototype.uncork = function () { 317 var state = this._writableState; 318 319 if (state.corked) { 320 state.corked--; 321 if (!state.writing && !state.corked && !state.bufferProcessing && state.bufferedRequest) clearBuffer(this, state); 322 } 323}; 324 325Writable.prototype.setDefaultEncoding = function setDefaultEncoding(encoding) { 326 // node::ParseEncoding() requires lower case. 327 if (typeof encoding === 'string') encoding = encoding.toLowerCase(); 328 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); 329 this._writableState.defaultEncoding = encoding; 330 return this; 331}; 332 333Object.defineProperty(Writable.prototype, 'writableBuffer', { 334 // making it explicit this property is not enumerable 335 // because otherwise some prototype manipulation in 336 // userland will fail 337 enumerable: false, 338 get: function get() { 339 return this._writableState && this._writableState.getBuffer(); 340 } 341}); 342 343function decodeChunk(state, chunk, encoding) { 344 if (!state.objectMode && state.decodeStrings !== false && typeof chunk === 'string') { 345 chunk = Buffer.from(chunk, encoding); 346 } 347 348 return chunk; 349} 350 351Object.defineProperty(Writable.prototype, 'writableHighWaterMark', { 352 // making it explicit this property is not enumerable 353 // because otherwise some prototype manipulation in 354 // userland will fail 355 enumerable: false, 356 get: function get() { 357 return this._writableState.highWaterMark; 358 } 359}); // if we're already writing something, then just put this 360// in the queue, and wait our turn. Otherwise, call _write 361// If we return false, then we need a drain event, so set that flag. 362 363function writeOrBuffer(stream, state, isBuf, chunk, encoding, cb) { 364 if (!isBuf) { 365 var newChunk = decodeChunk(state, chunk, encoding); 366 367 if (chunk !== newChunk) { 368 isBuf = true; 369 encoding = 'buffer'; 370 chunk = newChunk; 371 } 372 } 373 374 var len = state.objectMode ? 1 : chunk.length; 375 state.length += len; 376 var ret = state.length < state.highWaterMark; // we must ensure that previous needDrain will not be reset to false. 377 378 if (!ret) state.needDrain = true; 379 380 if (state.writing || state.corked) { 381 var last = state.lastBufferedRequest; 382 state.lastBufferedRequest = { 383 chunk: chunk, 384 encoding: encoding, 385 isBuf: isBuf, 386 callback: cb, 387 next: null 388 }; 389 390 if (last) { 391 last.next = state.lastBufferedRequest; 392 } else { 393 state.bufferedRequest = state.lastBufferedRequest; 394 } 395 396 state.bufferedRequestCount += 1; 397 } else { 398 doWrite(stream, state, false, len, chunk, encoding, cb); 399 } 400 401 return ret; 402} 403 404function doWrite(stream, state, writev, len, chunk, encoding, cb) { 405 state.writelen = len; 406 state.writecb = cb; 407 state.writing = true; 408 state.sync = true; 409 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); 410 state.sync = false; 411} 412 413function onwriteError(stream, state, sync, er, cb) { 414 --state.pendingcb; 415 416 if (sync) { 417 // defer the callback if we are being called synchronously 418 // to avoid piling up things on the stack 419 process.nextTick(cb, er); // this can emit finish, and it will always happen 420 // after error 421 422 process.nextTick(finishMaybe, stream, state); 423 stream._writableState.errorEmitted = true; 424 errorOrDestroy(stream, er); 425 } else { 426 // the caller expect this to happen before if 427 // it is async 428 cb(er); 429 stream._writableState.errorEmitted = true; 430 errorOrDestroy(stream, er); // this can emit finish, but finish must 431 // always follow error 432 433 finishMaybe(stream, state); 434 } 435} 436 437function onwriteStateUpdate(state) { 438 state.writing = false; 439 state.writecb = null; 440 state.length -= state.writelen; 441 state.writelen = 0; 442} 443 444function onwrite(stream, er) { 445 var state = stream._writableState; 446 var sync = state.sync; 447 var cb = state.writecb; 448 if (typeof cb !== 'function') throw new ERR_MULTIPLE_CALLBACK(); 449 onwriteStateUpdate(state); 450 if (er) onwriteError(stream, state, sync, er, cb);else { 451 // Check if we're actually ready to finish, but don't emit yet 452 var finished = needFinish(state) || stream.destroyed; 453 454 if (!finished && !state.corked && !state.bufferProcessing && state.bufferedRequest) { 455 clearBuffer(stream, state); 456 } 457 458 if (sync) { 459 process.nextTick(afterWrite, stream, state, finished, cb); 460 } else { 461 afterWrite(stream, state, finished, cb); 462 } 463 } 464} 465 466function afterWrite(stream, state, finished, cb) { 467 if (!finished) onwriteDrain(stream, state); 468 state.pendingcb--; 469 cb(); 470 finishMaybe(stream, state); 471} // Must force callback to be called on nextTick, so that we don't 472// emit 'drain' before the write() consumer gets the 'false' return 473// value, and has a chance to attach a 'drain' listener. 474 475 476function onwriteDrain(stream, state) { 477 if (state.length === 0 && state.needDrain) { 478 state.needDrain = false; 479 stream.emit('drain'); 480 } 481} // if there's something in the buffer waiting, then process it 482 483 484function clearBuffer(stream, state) { 485 state.bufferProcessing = true; 486 var entry = state.bufferedRequest; 487 488 if (stream._writev && entry && entry.next) { 489 // Fast case, write everything using _writev() 490 var l = state.bufferedRequestCount; 491 var buffer = new Array(l); 492 var holder = state.corkedRequestsFree; 493 holder.entry = entry; 494 var count = 0; 495 var allBuffers = true; 496 497 while (entry) { 498 buffer[count] = entry; 499 if (!entry.isBuf) allBuffers = false; 500 entry = entry.next; 501 count += 1; 502 } 503 504 buffer.allBuffers = allBuffers; 505 doWrite(stream, state, true, state.length, buffer, '', holder.finish); // doWrite is almost always async, defer these to save a bit of time 506 // as the hot path ends with doWrite 507 508 state.pendingcb++; 509 state.lastBufferedRequest = null; 510 511 if (holder.next) { 512 state.corkedRequestsFree = holder.next; 513 holder.next = null; 514 } else { 515 state.corkedRequestsFree = new CorkedRequest(state); 516 } 517 518 state.bufferedRequestCount = 0; 519 } else { 520 // Slow case, write chunks one-by-one 521 while (entry) { 522 var chunk = entry.chunk; 523 var encoding = entry.encoding; 524 var cb = entry.callback; 525 var len = state.objectMode ? 1 : chunk.length; 526 doWrite(stream, state, false, len, chunk, encoding, cb); 527 entry = entry.next; 528 state.bufferedRequestCount--; // if we didn't call the onwrite immediately, then 529 // it means that we need to wait until it does. 530 // also, that means that the chunk and cb are currently 531 // being processed, so move the buffer counter past them. 532 533 if (state.writing) { 534 break; 535 } 536 } 537 538 if (entry === null) state.lastBufferedRequest = null; 539 } 540 541 state.bufferedRequest = entry; 542 state.bufferProcessing = false; 543} 544 545Writable.prototype._write = function (chunk, encoding, cb) { 546 cb(new ERR_METHOD_NOT_IMPLEMENTED('_write()')); 547}; 548 549Writable.prototype._writev = null; 550 551Writable.prototype.end = function (chunk, encoding, cb) { 552 var state = this._writableState; 553 554 if (typeof chunk === 'function') { 555 cb = chunk; 556 chunk = null; 557 encoding = null; 558 } else if (typeof encoding === 'function') { 559 cb = encoding; 560 encoding = null; 561 } 562 563 if (chunk !== null && chunk !== undefined) this.write(chunk, encoding); // .end() fully uncorks 564 565 if (state.corked) { 566 state.corked = 1; 567 this.uncork(); 568 } // ignore unnecessary end() calls. 569 570 571 if (!state.ending) endWritable(this, state, cb); 572 return this; 573}; 574 575Object.defineProperty(Writable.prototype, 'writableLength', { 576 // making it explicit this property is not enumerable 577 // because otherwise some prototype manipulation in 578 // userland will fail 579 enumerable: false, 580 get: function get() { 581 return this._writableState.length; 582 } 583}); 584 585function needFinish(state) { 586 return state.ending && state.length === 0 && state.bufferedRequest === null && !state.finished && !state.writing; 587} 588 589function callFinal(stream, state) { 590 stream._final(function (err) { 591 state.pendingcb--; 592 593 if (err) { 594 errorOrDestroy(stream, err); 595 } 596 597 state.prefinished = true; 598 stream.emit('prefinish'); 599 finishMaybe(stream, state); 600 }); 601} 602 603function prefinish(stream, state) { 604 if (!state.prefinished && !state.finalCalled) { 605 if (typeof stream._final === 'function' && !state.destroyed) { 606 state.pendingcb++; 607 state.finalCalled = true; 608 process.nextTick(callFinal, stream, state); 609 } else { 610 state.prefinished = true; 611 stream.emit('prefinish'); 612 } 613 } 614} 615 616function finishMaybe(stream, state) { 617 var need = needFinish(state); 618 619 if (need) { 620 prefinish(stream, state); 621 622 if (state.pendingcb === 0) { 623 state.finished = true; 624 stream.emit('finish'); 625 626 if (state.autoDestroy) { 627 // In case of duplex streams we need a way to detect 628 // if the readable side is ready for autoDestroy as well 629 var rState = stream._readableState; 630 631 if (!rState || rState.autoDestroy && rState.endEmitted) { 632 stream.destroy(); 633 } 634 } 635 } 636 } 637 638 return need; 639} 640 641function endWritable(stream, state, cb) { 642 state.ending = true; 643 finishMaybe(stream, state); 644 645 if (cb) { 646 if (state.finished) process.nextTick(cb);else stream.once('finish', cb); 647 } 648 649 state.ended = true; 650 stream.writable = false; 651} 652 653function onCorkedFinish(corkReq, state, err) { 654 var entry = corkReq.entry; 655 corkReq.entry = null; 656 657 while (entry) { 658 var cb = entry.callback; 659 state.pendingcb--; 660 cb(err); 661 entry = entry.next; 662 } // reuse the free corkReq. 663 664 665 state.corkedRequestsFree.next = corkReq; 666} 667 668Object.defineProperty(Writable.prototype, 'destroyed', { 669 // making it explicit this property is not enumerable 670 // because otherwise some prototype manipulation in 671 // userland will fail 672 enumerable: false, 673 get: function get() { 674 if (this._writableState === undefined) { 675 return false; 676 } 677 678 return this._writableState.destroyed; 679 }, 680 set: function set(value) { 681 // we ignore the value if the stream 682 // has not been initialized yet 683 if (!this._writableState) { 684 return; 685 } // backward compatibility, the user is explicitly 686 // managing destroyed 687 688 689 this._writableState.destroyed = value; 690 } 691}); 692Writable.prototype.destroy = destroyImpl.destroy; 693Writable.prototype._undestroy = destroyImpl.undestroy; 694 695Writable.prototype._destroy = function (err, cb) { 696 cb(err); 697};