Current File : //home2/vacivi36/vittasync.vacivitta.com.br/vittasync/node/lib/internal/streams/readable.js
// 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.
'use strict';
const {
ArrayPrototypeIndexOf,
NumberIsInteger,
NumberIsNaN,
NumberParseInt,
ObjectDefineProperties,
ObjectKeys,
ObjectSetPrototypeOf,
Promise,
SafeSet,
Symbol,
SymbolAsyncDispose,
SymbolAsyncIterator,
SymbolSpecies,
TypedArrayPrototypeSet,
} = primordials;
module.exports = Readable;
Readable.ReadableState = ReadableState;
const EE = require('events');
const { Stream, prependListener } = require('internal/streams/legacy');
const { Buffer } = require('buffer');
const {
addAbortSignal,
} = require('internal/streams/add-abort-signal');
const eos = require('internal/streams/end-of-stream');
let debug = require('internal/util/debuglog').debuglog('stream', (fn) => {
debug = fn;
});
const destroyImpl = require('internal/streams/destroy');
const {
getHighWaterMark,
getDefaultHighWaterMark,
} = require('internal/streams/state');
const {
kState,
// bitfields
kObjectMode,
kErrorEmitted,
kAutoDestroy,
kEmitClose,
kDestroyed,
kClosed,
kCloseEmitted,
kErrored,
kConstructed,
kOnConstructed,
} = require('internal/streams/utils');
const {
aggregateTwoErrors,
codes: {
ERR_INVALID_ARG_TYPE,
ERR_METHOD_NOT_IMPLEMENTED,
ERR_OUT_OF_RANGE,
ERR_STREAM_PUSH_AFTER_EOF,
ERR_STREAM_UNSHIFT_AFTER_END_EVENT,
ERR_UNKNOWN_ENCODING,
},
AbortError,
} = require('internal/errors');
const { validateObject } = require('internal/validators');
const FastBuffer = Buffer[SymbolSpecies];
const { StringDecoder } = require('string_decoder');
const from = require('internal/streams/from');
ObjectSetPrototypeOf(Readable.prototype, Stream.prototype);
ObjectSetPrototypeOf(Readable, Stream);
const nop = () => {};
const { errorOrDestroy } = destroyImpl;
const kErroredValue = Symbol('kErroredValue');
const kDefaultEncodingValue = Symbol('kDefaultEncodingValue');
const kDecoderValue = Symbol('kDecoderValue');
const kEncodingValue = Symbol('kEncodingValue');
const kEnded = 1 << 9;
const kEndEmitted = 1 << 10;
const kReading = 1 << 11;
const kSync = 1 << 12;
const kNeedReadable = 1 << 13;
const kEmittedReadable = 1 << 14;
const kReadableListening = 1 << 15;
const kResumeScheduled = 1 << 16;
const kMultiAwaitDrain = 1 << 17;
const kReadingMore = 1 << 18;
const kDataEmitted = 1 << 19;
const kDefaultUTF8Encoding = 1 << 20;
const kDecoder = 1 << 21;
const kEncoding = 1 << 22;
const kHasFlowing = 1 << 23;
const kFlowing = 1 << 24;
const kHasPaused = 1 << 25;
const kPaused = 1 << 26;
const kDataListening = 1 << 27;
// TODO(benjamingr) it is likely slower to do it this way than with free functions
function makeBitMapDescriptor(bit) {
return {
enumerable: false,
get() { return (this[kState] & bit) !== 0; },
set(value) {
if (value) this[kState] |= bit;
else this[kState] &= ~bit;
},
};
}
ObjectDefineProperties(ReadableState.prototype, {
objectMode: makeBitMapDescriptor(kObjectMode),
ended: makeBitMapDescriptor(kEnded),
endEmitted: makeBitMapDescriptor(kEndEmitted),
reading: makeBitMapDescriptor(kReading),
// Stream is still being constructed and cannot be
// destroyed until construction finished or failed.
// Async construction is opt in, therefore we start as
// constructed.
constructed: makeBitMapDescriptor(kConstructed),
// A flag to be able to tell if the event 'readable'/'data' is emitted
// 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 read call.
sync: makeBitMapDescriptor(kSync),
// Whenever we return null, then we set a flag to say
// that we're awaiting a 'readable' event emission.
needReadable: makeBitMapDescriptor(kNeedReadable),
emittedReadable: makeBitMapDescriptor(kEmittedReadable),
readableListening: makeBitMapDescriptor(kReadableListening),
resumeScheduled: makeBitMapDescriptor(kResumeScheduled),
// True if the error was already emitted and should not be thrown again.
errorEmitted: makeBitMapDescriptor(kErrorEmitted),
emitClose: makeBitMapDescriptor(kEmitClose),
autoDestroy: makeBitMapDescriptor(kAutoDestroy),
// Has it been destroyed.
destroyed: makeBitMapDescriptor(kDestroyed),
// Indicates whether the stream has finished destroying.
closed: makeBitMapDescriptor(kClosed),
// True if close has been emitted or would have been emitted
// depending on emitClose.
closeEmitted: makeBitMapDescriptor(kCloseEmitted),
multiAwaitDrain: makeBitMapDescriptor(kMultiAwaitDrain),
// If true, a maybeReadMore has been scheduled.
readingMore: makeBitMapDescriptor(kReadingMore),
dataEmitted: makeBitMapDescriptor(kDataEmitted),
// Indicates whether the stream has errored. When true no further
// _read calls, 'data' or 'readable' events should occur. This is needed
// since when autoDestroy is disabled we need a way to tell whether the
// stream has failed.
errored: {
__proto__: null,
enumerable: false,
get() {
return (this[kState] & kErrored) !== 0 ? this[kErroredValue] : null;
},
set(value) {
if (value) {
this[kErroredValue] = value;
this[kState] |= kErrored;
} else {
this[kState] &= ~kErrored;
}
},
},
defaultEncoding: {
__proto__: null,
enumerable: false,
get() { return (this[kState] & kDefaultUTF8Encoding) !== 0 ? 'utf8' : this[kDefaultEncodingValue]; },
set(value) {
if (value === 'utf8' || value === 'utf-8') {
this[kState] |= kDefaultUTF8Encoding;
} else {
this[kState] &= ~kDefaultUTF8Encoding;
this[kDefaultEncodingValue] = value;
}
},
},
decoder: {
__proto__: null,
enumerable: false,
get() {
return (this[kState] & kDecoder) !== 0 ? this[kDecoderValue] : null;
},
set(value) {
if (value) {
this[kDecoderValue] = value;
this[kState] |= kDecoder;
} else {
this[kState] &= ~kDecoder;
}
},
},
encoding: {
__proto__: null,
enumerable: false,
get() {
return (this[kState] & kEncoding) !== 0 ? this[kEncodingValue] : null;
},
set(value) {
if (value) {
this[kEncodingValue] = value;
this[kState] |= kEncoding;
} else {
this[kState] &= ~kEncoding;
}
},
},
flowing: {
__proto__: null,
enumerable: false,
get() {
return (this[kState] & kHasFlowing) !== 0 ? (this[kState] & kFlowing) !== 0 : null;
},
set(value) {
if (value == null) {
this[kState] &= ~(kHasFlowing | kFlowing);
} else if (value) {
this[kState] |= (kHasFlowing | kFlowing);
} else {
this[kState] |= kHasFlowing;
this[kState] &= ~kFlowing;
}
},
},
});
function ReadableState(options, stream, isDuplex) {
// Bit map field to store ReadableState more effciently with 1 bit per field
// instead of a V8 slot per field.
this[kState] = kEmitClose | kAutoDestroy | kConstructed | kSync;
// Object stream flag. Used to make read(n) ignore n and to
// make all the buffer merging and length checks go away.
if (options && options.objectMode)
this[kState] |= kObjectMode;
if (isDuplex && options && options.readableObjectMode)
this[kState] |= kObjectMode;
// The point at which it stops calling _read() to fill the buffer
// Note: 0 is a valid value, means "don't call _read preemptively ever"
this.highWaterMark = options ?
getHighWaterMark(this, options, 'readableHighWaterMark', isDuplex) :
getDefaultHighWaterMark(false);
this.buffer = [];
this.bufferIndex = 0;
this.length = 0;
this.pipes = [];
// Should close be emitted on destroy. Defaults to true.
if (options && options.emitClose === false) this[kState] &= ~kEmitClose;
// Should .destroy() be called after 'end' (and potentially 'finish').
if (options && options.autoDestroy === false) this[kState] &= ~kAutoDestroy;
// 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.
const defaultEncoding = options?.defaultEncoding;
if (defaultEncoding == null || defaultEncoding === 'utf8' || defaultEncoding === 'utf-8') {
this[kState] |= kDefaultUTF8Encoding;
} else if (Buffer.isEncoding(defaultEncoding)) {
this.defaultEncoding = defaultEncoding;
} else {
throw new ERR_UNKNOWN_ENCODING(defaultEncoding);
}
// Ref the piped dest which we need a drain event on it
// type: null | Writable | Set<Writable>.
this.awaitDrainWriters = null;
if (options && options.encoding) {
this.decoder = new StringDecoder(options.encoding);
this.encoding = options.encoding;
}
}
ReadableState.prototype[kOnConstructed] = function onConstructed(stream) {
if ((this[kState] & kNeedReadable) !== 0) {
maybeReadMore(stream, this);
}
};
function Readable(options) {
if (!(this instanceof Readable))
return new Readable(options);
this._events ??= {
close: undefined,
error: undefined,
data: undefined,
end: undefined,
readable: undefined,
// Skip uncommon events...
// pause: undefined,
// resume: undefined,
// pipe: undefined,
// unpipe: undefined,
// [destroyImpl.kConstruct]: undefined,
// [destroyImpl.kDestroy]: undefined,
};
this._readableState = new ReadableState(options, this, false);
if (options) {
if (typeof options.read === 'function')
this._read = options.read;
if (typeof options.destroy === 'function')
this._destroy = options.destroy;
if (typeof options.construct === 'function')
this._construct = options.construct;
if (options.signal)
addAbortSignal(options.signal, this);
}
Stream.call(this, options);
if (this._construct != null) {
destroyImpl.construct(this, () => {
this._readableState[kOnConstructed](this);
});
}
}
Readable.prototype.destroy = destroyImpl.destroy;
Readable.prototype._undestroy = destroyImpl.undestroy;
Readable.prototype._destroy = function(err, cb) {
cb(err);
};
Readable.prototype[EE.captureRejectionSymbol] = function(err) {
this.destroy(err);
};
Readable.prototype[SymbolAsyncDispose] = function() {
let error;
if (!this.destroyed) {
error = this.readableEnded ? null : new AbortError();
this.destroy(error);
}
return new Promise((resolve, reject) => eos(this, (err) => (err && err !== error ? reject(err) : resolve(null))));
};
// Manually shove something into the read() buffer.
// This returns true if the highWaterMark has not been hit yet,
// similar to how Writable.write() returns true if you should
// write() some more.
Readable.prototype.push = function(chunk, encoding) {
debug('push', chunk);
const state = this._readableState;
return (state[kState] & kObjectMode) === 0 ?
readableAddChunkPushByteMode(this, state, chunk, encoding) :
readableAddChunkPushObjectMode(this, state, chunk, encoding);
};
// Unshift should *always* be something directly out of read().
Readable.prototype.unshift = function(chunk, encoding) {
debug('unshift', chunk);
const state = this._readableState;
return (state[kState] & kObjectMode) === 0 ?
readableAddChunkUnshiftByteMode(this, state, chunk, encoding) :
readableAddChunkUnshiftObjectMode(this, state, chunk);
};
function readableAddChunkUnshiftByteMode(stream, state, chunk, encoding) {
if (chunk === null) {
state[kState] &= ~kReading;
onEofChunk(stream, state);
return false;
}
if (typeof chunk === 'string') {
encoding = encoding || state.defaultEncoding;
if (state.encoding !== encoding) {
if (state.encoding) {
// When unshifting, if state.encoding is set, we have to save
// the string in the BufferList with the state encoding.
chunk = Buffer.from(chunk, encoding).toString(state.encoding);
} else {
chunk = Buffer.from(chunk, encoding);
}
}
} else if (Stream._isUint8Array(chunk)) {
chunk = Stream._uint8ArrayToBuffer(chunk);
} else if (chunk !== undefined && !(chunk instanceof Buffer)) {
errorOrDestroy(stream, new ERR_INVALID_ARG_TYPE(
'chunk', ['string', 'Buffer', 'Uint8Array'], chunk));
return false;
}
if (!(chunk && chunk.length > 0)) {
return canPushMore(state);
}
return readableAddChunkUnshiftValue(stream, state, chunk);
}
function readableAddChunkUnshiftObjectMode(stream, state, chunk) {
if (chunk === null) {
state[kState] &= ~kReading;
onEofChunk(stream, state);
return false;
}
return readableAddChunkUnshiftValue(stream, state, chunk);
}
function readableAddChunkUnshiftValue(stream, state, chunk) {
if ((state[kState] & kEndEmitted) !== 0)
errorOrDestroy(stream, new ERR_STREAM_UNSHIFT_AFTER_END_EVENT());
else if ((state[kState] & (kDestroyed | kErrored)) !== 0)
return false;
else
addChunk(stream, state, chunk, true);
return canPushMore(state);
}
function readableAddChunkPushByteMode(stream, state, chunk, encoding) {
if (chunk === null) {
state[kState] &= ~kReading;
onEofChunk(stream, state);
return false;
}
if (typeof chunk === 'string') {
encoding = encoding || state.defaultEncoding;
if (state.encoding !== encoding) {
chunk = Buffer.from(chunk, encoding);
encoding = '';
}
} else if (chunk instanceof Buffer) {
encoding = '';
} else if (Stream._isUint8Array(chunk)) {
chunk = Stream._uint8ArrayToBuffer(chunk);
encoding = '';
} else if (chunk !== undefined) {
errorOrDestroy(stream, new ERR_INVALID_ARG_TYPE(
'chunk', ['string', 'Buffer', 'Uint8Array'], chunk));
return false;
}
if (!chunk || chunk.length <= 0) {
state[kState] &= ~kReading;
maybeReadMore(stream, state);
return canPushMore(state);
}
if ((state[kState] & kEnded) !== 0) {
errorOrDestroy(stream, new ERR_STREAM_PUSH_AFTER_EOF());
return false;
}
if ((state[kState] & (kDestroyed | kErrored)) !== 0) {
return false;
}
state[kState] &= ~kReading;
if ((state[kState] & kDecoder) !== 0 && !encoding) {
chunk = state[kDecoderValue].write(chunk);
if (chunk.length === 0) {
maybeReadMore(stream, state);
return canPushMore(state);
}
}
addChunk(stream, state, chunk, false);
return canPushMore(state);
}
function readableAddChunkPushObjectMode(stream, state, chunk, encoding) {
if (chunk === null) {
state[kState] &= ~kReading;
onEofChunk(stream, state);
return false;
}
if ((state[kState] & kEnded) !== 0) {
errorOrDestroy(stream, new ERR_STREAM_PUSH_AFTER_EOF());
return false;
}
if ((state[kState] & (kDestroyed | kErrored)) !== 0) {
return false;
}
state[kState] &= ~kReading;
if ((state[kState] & kDecoder) !== 0 && !encoding) {
chunk = state[kDecoderValue].write(chunk);
}
addChunk(stream, state, chunk, false);
return canPushMore(state);
}
function canPushMore(state) {
// We can push more data if we are below the highWaterMark.
// Also, if we have no data yet, we can stand some more bytes.
// This is to work around cases where hwm=0, such as the repl.
return (state[kState] & kEnded) === 0 &&
(state.length < state.highWaterMark || state.length === 0);
}
function addChunk(stream, state, chunk, addToFront) {
if ((state[kState] & (kFlowing | kSync | kDataListening)) === (kFlowing | kDataListening) && state.length === 0) {
// Use the guard to avoid creating `Set()` repeatedly
// when we have multiple pipes.
if ((state[kState] & kMultiAwaitDrain) !== 0) {
state.awaitDrainWriters.clear();
} else {
state.awaitDrainWriters = null;
}
state[kState] |= kDataEmitted;
stream.emit('data', chunk);
} else {
// Update the buffer info.
state.length += (state[kState] & kObjectMode) !== 0 ? 1 : chunk.length;
if (addToFront) {
if (state.bufferIndex > 0) {
state.buffer[--state.bufferIndex] = chunk;
} else {
state.buffer.unshift(chunk); // Slow path
}
} else {
state.buffer.push(chunk);
}
if ((state[kState] & kNeedReadable) !== 0)
emitReadable(stream);
}
maybeReadMore(stream, state);
}
Readable.prototype.isPaused = function() {
const state = this._readableState;
return (state[kState] & kPaused) !== 0 || (state[kState] & (kHasFlowing | kFlowing)) === kHasFlowing;
};
// Backwards compatibility.
Readable.prototype.setEncoding = function(enc) {
const state = this._readableState;
const decoder = new StringDecoder(enc);
state.decoder = decoder;
// If setEncoding(null), decoder.encoding equals utf8.
state.encoding = state.decoder.encoding;
// Iterate over current buffer to convert already stored Buffers:
let content = '';
for (const data of state.buffer.slice(state.bufferIndex)) {
content += decoder.write(data);
}
state.buffer.length = 0;
state.bufferIndex = 0;
if (content !== '')
state.buffer.push(content);
state.length = content.length;
return this;
};
// Don't raise the hwm > 1GB.
const MAX_HWM = 0x40000000;
function computeNewHighWaterMark(n) {
if (n > MAX_HWM) {
throw new ERR_OUT_OF_RANGE('size', '<= 1GiB', n);
} else {
// Get the next highest power of 2 to prevent increasing hwm excessively in
// tiny amounts.
n--;
n |= n >>> 1;
n |= n >>> 2;
n |= n >>> 4;
n |= n >>> 8;
n |= n >>> 16;
n++;
}
return n;
}
// This function is designed to be inlinable, so please take care when making
// changes to the function body.
function howMuchToRead(n, state) {
if (n <= 0 || (state.length === 0 && (state[kState] & kEnded) !== 0))
return 0;
if ((state[kState] & kObjectMode) !== 0)
return 1;
if (NumberIsNaN(n)) {
// Only flow one buffer at a time.
if ((state[kState] & kFlowing) !== 0 && state.length)
return state.buffer[state.bufferIndex].length;
return state.length;
}
if (n <= state.length)
return n;
return (state[kState] & kEnded) !== 0 ? state.length : 0;
}
// You can override either this method, or the async _read(n) below.
Readable.prototype.read = function(n) {
debug('read', n);
// Same as parseInt(undefined, 10), however V8 7.3 performance regressed
// in this scenario, so we are doing it manually.
if (n === undefined) {
n = NaN;
} else if (!NumberIsInteger(n)) {
n = NumberParseInt(n, 10);
}
const state = this._readableState;
const nOrig = n;
// If we're asking for more than the current hwm, then raise the hwm.
if (n > state.highWaterMark)
state.highWaterMark = computeNewHighWaterMark(n);
if (n !== 0)
state[kState] &= ~kEmittedReadable;
// If we're doing read(0) to trigger a readable event, but we
// already have a bunch of data in the buffer, then just trigger
// the 'readable' event and move on.
if (n === 0 &&
(state[kState] & kNeedReadable) !== 0 &&
((state.highWaterMark !== 0 ?
state.length >= state.highWaterMark :
state.length > 0) ||
(state[kState] & kEnded) !== 0)) {
debug('read: emitReadable');
if (state.length === 0 && (state[kState] & kEnded) !== 0)
endReadable(this);
else
emitReadable(this);
return null;
}
n = howMuchToRead(n, state);
// If we've ended, and we're now clear, then finish it up.
if (n === 0 && (state[kState] & kEnded) !== 0) {
if (state.length === 0)
endReadable(this);
return null;
}
// All the actual chunk generation logic needs to be
// *below* the call to _read. The reason is that in certain
// synthetic stream cases, such as passthrough streams, _read
// may be a completely synchronous operation which may change
// the state of the read buffer, providing enough data when
// before there was *not* enough.
//
// So, the steps are:
// 1. Figure out what the state of things will be after we do
// a read from the buffer.
//
// 2. If that resulting state will trigger a _read, then call _read.
// Note that this may be asynchronous, or synchronous. Yes, it is
// deeply ugly to write APIs this way, but that still doesn't mean
// that the Readable class should behave improperly, as streams are
// designed to be sync/async agnostic.
// Take note if the _read call is sync or async (ie, if the read call
// has returned yet), so that we know whether or not it's safe to emit
// 'readable' etc.
//
// 3. Actually pull the requested chunks out of the buffer and return.
// if we need a readable event, then we need to do some reading.
let doRead = (state[kState] & kNeedReadable) !== 0;
debug('need readable', doRead);
// If we currently have less than the highWaterMark, then also read some.
if (state.length === 0 || state.length - n < state.highWaterMark) {
doRead = true;
debug('length less than watermark', doRead);
}
// However, if we've ended, then there's no point, if we're already
// reading, then it's unnecessary, if we're constructing we have to wait,
// and if we're destroyed or errored, then it's not allowed,
if ((state[kState] & (kReading | kEnded | kDestroyed | kErrored | kConstructed)) !== kConstructed) {
doRead = false;
debug('reading, ended or constructing', doRead);
} else if (doRead) {
debug('do read');
state[kState] |= kReading | kSync;
// If the length is currently zero, then we *need* a readable event.
if (state.length === 0)
state[kState] |= kNeedReadable;
// Call internal read method
try {
this._read(state.highWaterMark);
} catch (err) {
errorOrDestroy(this, err);
}
state[kState] &= ~kSync;
// If _read pushed data synchronously, then `reading` will be false,
// and we need to re-evaluate how much data we can return to the user.
if ((state[kState] & kReading) === 0)
n = howMuchToRead(nOrig, state);
}
let ret;
if (n > 0)
ret = fromList(n, state);
else
ret = null;
if (ret === null) {
state[kState] |= state.length <= state.highWaterMark ? kNeedReadable : 0;
n = 0;
} else {
state.length -= n;
if ((state[kState] & kMultiAwaitDrain) !== 0) {
state.awaitDrainWriters.clear();
} else {
state.awaitDrainWriters = null;
}
}
if (state.length === 0) {
// If we have nothing in the buffer, then we want to know
// as soon as we *do* get something into the buffer.
if ((state[kState] & kEnded) === 0)
state[kState] |= kNeedReadable;
// If we tried to read() past the EOF, then emit end on the next tick.
if (nOrig !== n && (state[kState] & kEnded) !== 0)
endReadable(this);
}
if (ret !== null && (state[kState] & (kErrorEmitted | kCloseEmitted)) === 0) {
state[kState] |= kDataEmitted;
this.emit('data', ret);
}
return ret;
};
function onEofChunk(stream, state) {
debug('onEofChunk');
if ((state[kState] & kEnded) !== 0) return;
const decoder = (state[kState] & kDecoder) !== 0 ? state[kDecoderValue] : null;
if (decoder) {
const chunk = decoder.end();
if (chunk && chunk.length) {
state.buffer.push(chunk);
state.length += (state[kState] & kObjectMode) !== 0 ? 1 : chunk.length;
}
}
state[kState] |= kEnded;
if ((state[kState] & kSync) !== 0) {
// If we are sync, wait until next tick to emit the data.
// Otherwise we risk emitting data in the flow()
// the readable code triggers during a read() call.
emitReadable(stream);
} else {
// Emit 'readable' now to make sure it gets picked up.
state[kState] &= ~kNeedReadable;
state[kState] |= kEmittedReadable;
// We have to emit readable now that we are EOF. Modules
// in the ecosystem (e.g. dicer) rely on this event being sync.
emitReadable_(stream);
}
}
// Don't emit readable right away in sync mode, because this can trigger
// another read() call => stack overflow. This way, it might trigger
// a nextTick recursion warning, but that's not so bad.
function emitReadable(stream) {
const state = stream._readableState;
debug('emitReadable');
state[kState] &= ~kNeedReadable;
if ((state[kState] & kEmittedReadable) === 0) {
debug('emitReadable', (state[kState] & kFlowing) !== 0);
state[kState] |= kEmittedReadable;
process.nextTick(emitReadable_, stream);
}
}
function emitReadable_(stream) {
const state = stream._readableState;
debug('emitReadable_');
if ((state[kState] & (kDestroyed | kErrored)) === 0 && (state.length || (state[kState] & kEnded) !== 0)) {
stream.emit('readable');
state[kState] &= ~kEmittedReadable;
}
// The stream needs another readable event if:
// 1. It is not flowing, as the flow mechanism will take
// care of it.
// 2. It is not ended.
// 3. It is below the highWaterMark, so we can schedule
// another readable later.
state[kState] |=
(state[kState] & (kFlowing | kEnded)) === 0 &&
state.length <= state.highWaterMark ? kNeedReadable : 0;
flow(stream);
}
// At this point, the user has presumably seen the 'readable' event,
// and called read() to consume some data. that may have triggered
// in turn another _read(n) call, in which case reading = true if
// it's in progress.
// However, if we're not ended, or reading, and the length < hwm,
// then go ahead and try to read some more preemptively.
function maybeReadMore(stream, state) {
if ((state[kState] & (kReadingMore | kConstructed)) === kConstructed) {
state[kState] |= kReadingMore;
process.nextTick(maybeReadMore_, stream, state);
}
}
function maybeReadMore_(stream, state) {
// Attempt to read more data if we should.
//
// The conditions for reading more data are (one of):
// - Not enough data buffered (state.length < state.highWaterMark). The loop
// is responsible for filling the buffer with enough data if such data
// is available. If highWaterMark is 0 and we are not in the flowing mode
// we should _not_ attempt to buffer any extra data. We'll get more data
// when the stream consumer calls read() instead.
// - No data in the buffer, and the stream is in flowing mode. In this mode
// the loop below is responsible for ensuring read() is called. Failing to
// call read here would abort the flow and there's no other mechanism for
// continuing the flow if the stream consumer has just subscribed to the
// 'data' event.
//
// In addition to the above conditions to keep reading data, the following
// conditions prevent the data from being read:
// - The stream has ended (state.ended).
// - There is already a pending 'read' operation (state.reading). This is a
// case where the stream has called the implementation defined _read()
// method, but they are processing the call asynchronously and have _not_
// called push() with new data. In this case we skip performing more
// read()s. The execution ends in this method again after the _read() ends
// up calling push() with more data.
while ((state[kState] & (kReading | kEnded)) === 0 &&
(state.length < state.highWaterMark ||
((state[kState] & kFlowing) !== 0 && state.length === 0))) {
const len = state.length;
debug('maybeReadMore read 0');
stream.read(0);
if (len === state.length)
// Didn't get any data, stop spinning.
break;
}
state[kState] &= ~kReadingMore;
}
// 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) {
throw new ERR_METHOD_NOT_IMPLEMENTED('_read()');
};
Readable.prototype.pipe = function(dest, pipeOpts) {
const src = this;
const state = this._readableState;
if (state.pipes.length === 1) {
if ((state[kState] & kMultiAwaitDrain) === 0) {
state[kState] |= kMultiAwaitDrain;
state.awaitDrainWriters = new SafeSet(
state.awaitDrainWriters ? [state.awaitDrainWriters] : [],
);
}
}
state.pipes.push(dest);
debug('pipe count=%d opts=%j', state.pipes.length, pipeOpts);
const doEnd = (!pipeOpts || pipeOpts.end !== false) &&
dest !== process.stdout &&
dest !== process.stderr;
const endFn = doEnd ? onend : unpipe;
if ((state[kState] & kEndEmitted) !== 0)
process.nextTick(endFn);
else
src.once('end', endFn);
dest.on('unpipe', onunpipe);
function onunpipe(readable, unpipeInfo) {
debug('onunpipe');
if (readable === src) {
if (unpipeInfo && unpipeInfo.hasUnpiped === false) {
unpipeInfo.hasUnpiped = true;
cleanup();
}
}
}
function onend() {
debug('onend');
dest.end();
}
let ondrain;
let cleanedUp = false;
function cleanup() {
debug('cleanup');
// Cleanup event handlers once the pipe is broken.
dest.removeListener('close', onclose);
dest.removeListener('finish', onfinish);
if (ondrain) {
dest.removeListener('drain', ondrain);
}
dest.removeListener('error', onerror);
dest.removeListener('unpipe', onunpipe);
src.removeListener('end', onend);
src.removeListener('end', unpipe);
src.removeListener('data', ondata);
cleanedUp = true;
// If the reader is waiting for a drain event from this
// specific writer, then it would cause it to never start
// flowing again.
// So, if this is awaiting a drain, then we just call it now.
// If we don't know, then assume that we are waiting for one.
if (ondrain && state.awaitDrainWriters &&
(!dest._writableState || dest._writableState.needDrain))
ondrain();
}
function pause() {
// If the user unpiped during `dest.write()`, it is possible
// to get stuck in a permanently paused state if that write
// also returned false.
// => Check whether `dest` is still a piping destination.
if (!cleanedUp) {
if (state.pipes.length === 1 && state.pipes[0] === dest) {
debug('false write response, pause', 0);
state.awaitDrainWriters = dest;
state[kState] &= ~kMultiAwaitDrain;
} else if (state.pipes.length > 1 && state.pipes.includes(dest)) {
debug('false write response, pause', state.awaitDrainWriters.size);
state.awaitDrainWriters.add(dest);
}
src.pause();
}
if (!ondrain) {
// When the dest drains, it reduces the awaitDrain counter
// on the source. This would be more elegant with a .once()
// handler in flow(), but adding and removing repeatedly is
// too slow.
ondrain = pipeOnDrain(src, dest);
dest.on('drain', ondrain);
}
}
src.on('data', ondata);
function ondata(chunk) {
debug('ondata');
const ret = dest.write(chunk);
debug('dest.write', ret);
if (ret === false) {
pause();
}
}
// If the dest has an error, then stop piping into it.
// However, don't suppress the throwing behavior for this.
function onerror(er) {
debug('onerror', er);
unpipe();
dest.removeListener('error', onerror);
if (dest.listenerCount('error') === 0) {
const s = dest._writableState || dest._readableState;
if (s && !s.errorEmitted) {
// User incorrectly emitted 'error' directly on the stream.
errorOrDestroy(dest, er);
} else {
dest.emit('error', er);
}
}
}
// Make sure our error handler is attached before userland ones.
prependListener(dest, 'error', onerror);
// Both close and finish should trigger unpipe, but only once.
function onclose() {
dest.removeListener('finish', onfinish);
unpipe();
}
dest.once('close', onclose);
function onfinish() {
debug('onfinish');
dest.removeListener('close', onclose);
unpipe();
}
dest.once('finish', onfinish);
function unpipe() {
debug('unpipe');
src.unpipe(dest);
}
// Tell the dest that it's being piped to.
dest.emit('pipe', src);
// Start the flow if it hasn't been started already.
if (dest.writableNeedDrain === true) {
pause();
} else if ((state[kState] & kFlowing) === 0) {
debug('pipe resume');
src.resume();
}
return dest;
};
function pipeOnDrain(src, dest) {
return function pipeOnDrainFunctionResult() {
const state = src._readableState;
// `ondrain` will call directly,
// `this` maybe not a reference to dest,
// so we use the real dest here.
if (state.awaitDrainWriters === dest) {
debug('pipeOnDrain', 1);
state.awaitDrainWriters = null;
} else if ((state[kState] & kMultiAwaitDrain) !== 0) {
debug('pipeOnDrain', state.awaitDrainWriters.size);
state.awaitDrainWriters.delete(dest);
}
if ((!state.awaitDrainWriters || state.awaitDrainWriters.size === 0) &&
(state[kState] & kDataListening) !== 0) {
src.resume();
}
};
}
Readable.prototype.unpipe = function(dest) {
const state = this._readableState;
const unpipeInfo = { hasUnpiped: false };
// If we're not piping anywhere, then do nothing.
if (state.pipes.length === 0)
return this;
if (!dest) {
// remove all.
const dests = state.pipes;
state.pipes = [];
this.pause();
for (let i = 0; i < dests.length; i++)
dests[i].emit('unpipe', this, { hasUnpiped: false });
return this;
}
// Try to find the right one.
const index = ArrayPrototypeIndexOf(state.pipes, dest);
if (index === -1)
return this;
state.pipes.splice(index, 1);
if (state.pipes.length === 0)
this.pause();
dest.emit('unpipe', this, unpipeInfo);
return this;
};
// Set up data events if they are asked for
// Ensure readable listeners eventually get something.
Readable.prototype.on = function(ev, fn) {
const res = Stream.prototype.on.call(this, ev, fn);
const state = this._readableState;
if (ev === 'data') {
state[kState] |= kDataListening;
// Update readableListening so that resume() may be a no-op
// a few lines down. This is needed to support once('readable').
state[kState] |= this.listenerCount('readable') > 0 ? kReadableListening : 0;
// Try start flowing on next tick if stream isn't explicitly paused.
if ((state[kState] & (kHasFlowing | kFlowing)) !== kHasFlowing) {
this.resume();
}
} else if (ev === 'readable') {
if ((state[kState] & (kEndEmitted | kReadableListening)) === 0) {
state[kState] |= kReadableListening | kNeedReadable | kHasFlowing;
state[kState] &= ~(kFlowing | kEmittedReadable);
debug('on readable');
if (state.length) {
emitReadable(this);
} else if ((state[kState] & kReading) === 0) {
process.nextTick(nReadingNextTick, this);
}
}
}
return res;
};
Readable.prototype.addListener = Readable.prototype.on;
Readable.prototype.removeListener = function(ev, fn) {
const state = this._readableState;
const res = Stream.prototype.removeListener.call(this,
ev, fn);
if (ev === 'readable') {
// We need to check if there is someone still listening to
// readable and reset the state. However this needs to happen
// after readable has been emitted but before I/O (nextTick) to
// support once('readable', fn) cycles. This means that calling
// resume within the same tick will have no
// effect.
process.nextTick(updateReadableListening, this);
} else if (ev === 'data' && this.listenerCount('data') === 0) {
state[kState] &= ~kDataListening;
}
return res;
};
Readable.prototype.off = Readable.prototype.removeListener;
Readable.prototype.removeAllListeners = function(ev) {
const res = Stream.prototype.removeAllListeners.apply(this,
arguments);
if (ev === 'readable' || ev === undefined) {
// We need to check if there is someone still listening to
// readable and reset the state. However this needs to happen
// after readable has been emitted but before I/O (nextTick) to
// support once('readable', fn) cycles. This means that calling
// resume within the same tick will have no
// effect.
process.nextTick(updateReadableListening, this);
}
return res;
};
function updateReadableListening(self) {
const state = self._readableState;
if (self.listenerCount('readable') > 0) {
state[kState] |= kReadableListening;
} else {
state[kState] &= ~kReadableListening;
}
if ((state[kState] & (kHasPaused | kPaused | kResumeScheduled)) === (kHasPaused | kResumeScheduled)) {
// Flowing needs to be set to true now, otherwise
// the upcoming resume will not flow.
state[kState] |= kHasFlowing | kFlowing;
// Crude way to check if we should resume.
} else if ((state[kState] & kDataListening) !== 0) {
self.resume();
} else if ((state[kState] & kReadableListening) === 0) {
state[kState] &= ~(kHasFlowing | kFlowing);
}
}
function nReadingNextTick(self) {
debug('readable nexttick read 0');
self.read(0);
}
// 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() {
const state = this._readableState;
if ((state[kState] & kFlowing) === 0) {
debug('resume');
// We flow only if there is no one listening
// for readable, but we still have to call
// resume().
state[kState] |= kHasFlowing;
if ((state[kState] & kReadableListening) === 0) {
state[kState] |= kFlowing;
} else {
state[kState] &= ~kFlowing;
}
resume(this, state);
}
state[kState] |= kHasPaused;
state[kState] &= ~kPaused;
return this;
};
function resume(stream, state) {
if ((state[kState] & kResumeScheduled) === 0) {
state[kState] |= kResumeScheduled;
process.nextTick(resume_, stream, state);
}
}
function resume_(stream, state) {
debug('resume', (state[kState] & kReading) !== 0);
if ((state[kState] & kReading) === 0) {
stream.read(0);
}
state[kState] &= ~kResumeScheduled;
stream.emit('resume');
flow(stream);
if ((state[kState] & (kFlowing | kReading)) === kFlowing)
stream.read(0);
}
Readable.prototype.pause = function() {
const state = this._readableState;
debug('call pause');
if ((state[kState] & (kHasFlowing | kFlowing)) !== kHasFlowing) {
debug('pause');
state[kState] |= kHasFlowing;
state[kState] &= ~kFlowing;
this.emit('pause');
}
state[kState] |= kHasPaused | kPaused;
return this;
};
function flow(stream) {
const state = stream._readableState;
debug('flow');
while ((state[kState] & kFlowing) !== 0 && stream.read() !== null);
}
// 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) {
let paused = false;
// TODO (ronag): Should this.destroy(err) emit
// 'error' on the wrapped stream? Would require
// a static factory method, e.g. Readable.wrap(stream).
stream.on('data', (chunk) => {
if (!this.push(chunk) && stream.pause) {
paused = true;
stream.pause();
}
});
stream.on('end', () => {
this.push(null);
});
stream.on('error', (err) => {
errorOrDestroy(this, err);
});
stream.on('close', () => {
this.destroy();
});
stream.on('destroy', () => {
this.destroy();
});
this._read = () => {
if (paused && stream.resume) {
paused = false;
stream.resume();
}
};
// Proxy all the other methods. Important when wrapping filters and duplexes.
const streamKeys = ObjectKeys(stream);
for (let j = 1; j < streamKeys.length; j++) {
const i = streamKeys[j];
if (this[i] === undefined && typeof stream[i] === 'function') {
this[i] = stream[i].bind(stream);
}
}
return this;
};
Readable.prototype[SymbolAsyncIterator] = function() {
return streamToAsyncIterator(this);
};
Readable.prototype.iterator = function(options) {
if (options !== undefined) {
validateObject(options, 'options');
}
return streamToAsyncIterator(this, options);
};
function streamToAsyncIterator(stream, options) {
if (typeof stream.read !== 'function') {
stream = Readable.wrap(stream, { objectMode: true });
}
const iter = createAsyncIterator(stream, options);
iter.stream = stream;
return iter;
}
async function* createAsyncIterator(stream, options) {
let callback = nop;
function next(resolve) {
if (this === stream) {
callback();
callback = nop;
} else {
callback = resolve;
}
}
stream.on('readable', next);
let error;
const cleanup = eos(stream, { writable: false }, (err) => {
error = err ? aggregateTwoErrors(error, err) : null;
callback();
callback = nop;
});
try {
while (true) {
const chunk = stream.destroyed ? null : stream.read();
if (chunk !== null) {
yield chunk;
} else if (error) {
throw error;
} else if (error === null) {
return;
} else {
await new Promise(next);
}
}
} catch (err) {
error = aggregateTwoErrors(error, err);
throw error;
} finally {
if (
(error || options?.destroyOnReturn !== false) &&
(error === undefined || stream._readableState.autoDestroy)
) {
destroyImpl.destroyer(stream, null);
} else {
stream.off('readable', next);
cleanup();
}
}
}
// Making it explicit these properties are not enumerable
// because otherwise some prototype manipulation in
// userland will fail.
ObjectDefineProperties(Readable.prototype, {
readable: {
__proto__: null,
get() {
const r = this._readableState;
// r.readable === false means that this is part of a Duplex stream
// where the readable side was disabled upon construction.
// Compat. The user might manually disable readable side through
// deprecated setter.
return !!r && r.readable !== false && !r.destroyed && !r.errorEmitted &&
!r.endEmitted;
},
set(val) {
// Backwards compat.
if (this._readableState) {
this._readableState.readable = !!val;
}
},
},
readableDidRead: {
__proto__: null,
enumerable: false,
get: function() {
return this._readableState.dataEmitted;
},
},
readableAborted: {
__proto__: null,
enumerable: false,
get: function() {
return !!(
this._readableState.readable !== false &&
(this._readableState.destroyed || this._readableState.errored) &&
!this._readableState.endEmitted
);
},
},
readableHighWaterMark: {
__proto__: null,
enumerable: false,
get: function() {
return this._readableState.highWaterMark;
},
},
readableBuffer: {
__proto__: null,
enumerable: false,
get: function() {
return this._readableState && this._readableState.buffer;
},
},
readableFlowing: {
__proto__: null,
enumerable: false,
get: function() {
return this._readableState.flowing;
},
set: function(state) {
if (this._readableState) {
this._readableState.flowing = state;
}
},
},
readableLength: {
__proto__: null,
enumerable: false,
get() {
return this._readableState.length;
},
},
readableObjectMode: {
__proto__: null,
enumerable: false,
get() {
return this._readableState ? this._readableState.objectMode : false;
},
},
readableEncoding: {
__proto__: null,
enumerable: false,
get() {
return this._readableState ? this._readableState.encoding : null;
},
},
errored: {
__proto__: null,
enumerable: false,
get() {
return this._readableState ? this._readableState.errored : null;
},
},
closed: {
__proto__: null,
get() {
return this._readableState ? this._readableState.closed : false;
},
},
destroyed: {
__proto__: null,
enumerable: false,
get() {
return this._readableState ? this._readableState.destroyed : false;
},
set(value) {
// We ignore the value if the stream
// has not been initialized yet.
if (!this._readableState) {
return;
}
// Backward compatibility, the user is explicitly
// managing destroyed.
this._readableState.destroyed = value;
},
},
readableEnded: {
__proto__: null,
enumerable: false,
get() {
return this._readableState ? this._readableState.endEmitted : false;
},
},
});
ObjectDefineProperties(ReadableState.prototype, {
// Legacy getter for `pipesCount`.
pipesCount: {
__proto__: null,
get() {
return this.pipes.length;
},
},
// Legacy property for `paused`.
paused: {
__proto__: null,
get() {
return (this[kState] & kPaused) !== 0;
},
set(value) {
this[kState] |= kHasPaused;
if (value) {
this[kState] |= kPaused;
} else {
this[kState] &= ~kPaused;
}
},
},
});
// 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.
// This function is designed to be inlinable, so please take care when making
// changes to the function body.
function fromList(n, state) {
// nothing buffered.
if (state.length === 0)
return null;
let idx = state.bufferIndex;
let ret;
const buf = state.buffer;
const len = buf.length;
if ((state[kState] & kObjectMode) !== 0) {
ret = buf[idx];
buf[idx++] = null;
} else if (!n || n >= state.length) {
// Read it all, truncate the list.
if ((state[kState] & kDecoder) !== 0) {
ret = '';
while (idx < len) {
ret += buf[idx];
buf[idx++] = null;
}
} else if (len - idx === 0) {
ret = Buffer.alloc(0);
} else if (len - idx === 1) {
ret = buf[idx];
buf[idx++] = null;
} else {
ret = Buffer.allocUnsafe(state.length);
let i = 0;
while (idx < len) {
TypedArrayPrototypeSet(ret, buf[idx], i);
i += buf[idx].length;
buf[idx++] = null;
}
}
} else if (n < buf[idx].length) {
// `slice` is the same for buffers and strings.
ret = buf[idx].slice(0, n);
buf[idx] = buf[idx].slice(n);
} else if (n === buf[idx].length) {
// First chunk is a perfect match.
ret = buf[idx];
buf[idx++] = null;
} else if ((state[kState] & kDecoder) !== 0) {
ret = '';
while (idx < len) {
const str = buf[idx];
if (n > str.length) {
ret += str;
n -= str.length;
buf[idx++] = null;
} else {
if (n === buf.length) {
ret += str;
buf[idx++] = null;
} else {
ret += str.slice(0, n);
buf[idx] = str.slice(n);
}
break;
}
}
} else {
ret = Buffer.allocUnsafe(n);
const retLen = n;
while (idx < len) {
const data = buf[idx];
if (n > data.length) {
TypedArrayPrototypeSet(ret, data, retLen - n);
n -= data.length;
buf[idx++] = null;
} else {
if (n === data.length) {
TypedArrayPrototypeSet(ret, data, retLen - n);
buf[idx++] = null;
} else {
TypedArrayPrototypeSet(ret, new FastBuffer(data.buffer, data.byteOffset, n), retLen - n);
buf[idx] = new FastBuffer(data.buffer, data.byteOffset + n, data.length - n);
}
break;
}
}
}
if (idx === len) {
state.buffer.length = 0;
state.bufferIndex = 0;
} else if (idx > 1024) {
state.buffer.splice(0, idx);
state.bufferIndex = 0;
} else {
state.bufferIndex = idx;
}
return ret;
}
function endReadable(stream) {
const state = stream._readableState;
debug('endReadable');
if ((state[kState] & kEndEmitted) === 0) {
state[kState] |= kEnded;
process.nextTick(endReadableNT, state, stream);
}
}
function endReadableNT(state, stream) {
debug('endReadableNT');
// Check that we didn't get one last unshift.
if ((state[kState] & (kErrored | kCloseEmitted | kEndEmitted)) === 0 && state.length === 0) {
state[kState] |= kEndEmitted;
stream.emit('end');
if (stream.writable && stream.allowHalfOpen === false) {
process.nextTick(endWritableNT, stream);
} else if (state.autoDestroy) {
// In case of duplex streams we need a way to detect
// if the writable side is ready for autoDestroy as well.
const wState = stream._writableState;
const autoDestroy = !wState || (
wState.autoDestroy &&
// We don't expect the writable to ever 'finish'
// if writable is explicitly set to false.
(wState.finished || wState.writable === false)
);
if (autoDestroy) {
stream.destroy();
}
}
}
}
function endWritableNT(stream) {
const writable = stream.writable && !stream.writableEnded &&
!stream.destroyed;
if (writable) {
stream.end();
}
}
Readable.from = function(iterable, opts) {
return from(Readable, iterable, opts);
};
let webStreamsAdapters;
// Lazy to avoid circular references
function lazyWebStreams() {
if (webStreamsAdapters === undefined)
webStreamsAdapters = require('internal/webstreams/adapters');
return webStreamsAdapters;
}
Readable.fromWeb = function(readableStream, options) {
return lazyWebStreams().newStreamReadableFromReadableStream(
readableStream,
options);
};
Readable.toWeb = function(streamReadable, options) {
return lazyWebStreams().newReadableStreamFromStreamReadable(
streamReadable,
options);
};
Readable.wrap = function(src, options) {
return new Readable({
objectMode: src.readableObjectMode ?? src.objectMode ?? true,
...options,
destroy(err, callback) {
destroyImpl.destroyer(src, err);
callback(err);
},
}).wrap(src);
};
Mini Shell