stream: readable use bitmap accessors

PR-URL: nodejs#50350
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Raz Luvaton <rluvaton@gmail.com>

Author: ronag

lib/internal/streams/readable.js

@@ -431,7 +431,7 @@ function readableAddChunkUnshiftObjectMode(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.destroyed || state.errored)
+  else if ((state[kState] & (kDestroyed | kErrored)) !== 0)
     return false;
   else
     addChunk(stream, state, chunk, true);
@@ -608,7 +608,7 @@ function computeNewHighWaterMark(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.ended))
+  if (n <= 0 || (state.length === 0 && (state[kState] & kEnded) !== 0))
     return 0;
   if ((state[kState] & kObjectMode) !== 0)
     return 1;
@@ -652,7 +652,7 @@ Readable.prototype.read = function(n) {
         state.length >= state.highWaterMark :
         state.length > 0) ||
        (state[kState] & kEnded) !== 0)) {
-    debug('read: emitReadable', state.length, (state[kState] & kEnded) !== 0);
+    debug('read: emitReadable');
     if (state.length === 0 && (state[kState] & kEnded) !== 0)
       endReadable(this);
     else
@@ -810,7 +810,7 @@ function emitReadable(stream) {
 function emitReadable_(stream) {
   const state = stream._readableState;
   debug('emitReadable_');
-  if ((state[kState] & (kDestroyed | kErrored)) === 0 && (state.length || state.ended)) {
+  if ((state[kState] & (kDestroyed | kErrored)) === 0 && (state.length || (state[kState] & kEnded) !== 0)) {
     stream.emit('readable');
     state[kState] &= ~kEmittedReadable;
   }
@@ -891,7 +891,7 @@ Readable.prototype.pipe = function(dest, pipeOpts) {
   const state = this._readableState;
 
   if (state.pipes.length === 1) {
-    if (!state.multiAwaitDrain) {
+    if ((state[kState] & kMultiAwaitDrain) === 0) {
       state[kState] |= kMultiAwaitDrain;
       state.awaitDrainWriters = new SafeSet(
         state.awaitDrainWriters ? [state.awaitDrainWriters] : [],
@@ -907,7 +907,7 @@ Readable.prototype.pipe = function(dest, pipeOpts) {
               dest !== process.stderr;
 
   const endFn = doEnd ? onend : unpipe;
-  if (state.endEmitted)
+  if ((state[kState] & kEndEmitted) !== 0)
     process.nextTick(endFn);
   else
     src.once('end', endFn);
@@ -966,7 +966,7 @@ Readable.prototype.pipe = function(dest, pipeOpts) {
       if (state.pipes.length === 1 && state.pipes[0] === dest) {
         debug('false write response, pause', 0);
         state.awaitDrainWriters = dest;
-        state.multiAwaitDrain = false;
+        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);
@@ -1038,7 +1038,7 @@ Readable.prototype.pipe = function(dest, pipeOpts) {
 
   if (dest.writableNeedDrain === true) {
     pause();
-  } else if (!state.flowing) {
+  } else if ((state[kState] & kFlowing) === 0) {
     debug('pipe resume');
     src.resume();
   }
@@ -1056,7 +1056,7 @@ function pipeOnDrain(src, dest) {
     if (state.awaitDrainWriters === dest) {
       debug('pipeOnDrain', 1);
       state.awaitDrainWriters = null;
-    } else if (state.multiAwaitDrain) {
+    } else if ((state[kState] & kMultiAwaitDrain) !== 0) {
       debug('pipeOnDrain', state.awaitDrainWriters.size);
       state.awaitDrainWriters.delete(dest);
     }
@@ -1111,20 +1111,20 @@ Readable.prototype.on = function(ev, fn) {
   if (ev === 'data') {
     // Update readableListening so that resume() may be a no-op
     // a few lines down. This is needed to support once('readable').
-    state.readableListening = this.listenerCount('readable') > 0;
+    state[kState] |= this.listenerCount('readable') > 0 ? kReadableListening : 0;
 
     // Try start flowing on next tick if stream isn't explicitly paused.
-    if (state.flowing !== false)
+    if ((state[kState] & (kHasFlowing | kFlowing)) !== kHasFlowing) {
       this.resume();
+    }
   } else if (ev === 'readable') {
-    if (!state.endEmitted && !state.readableListening) {
-      state.readableListening = state.needReadable = true;
-      state.flowing = false;
-      state.emittedReadable = false;
-      debug('on readable', state.length, state.reading);
+    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.reading) {
+      } else if ((state[kState] & kReading) === 0) {
         process.nextTick(nReadingNextTick, this);
       }
     }
@@ -1171,7 +1171,12 @@ Readable.prototype.removeAllListeners = function(ev) {
 
 function updateReadableListening(self) {
   const state = self._readableState;
-  state.readableListening = self.listenerCount('readable') > 0;
+
+  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
@@ -1201,7 +1206,7 @@ Readable.prototype.resume = function() {
     // for readable, but we still have to call
     // resume().
     state[kState] |= kHasFlowing;
-    if (!state.readableListening) {
+    if ((state[kState] & kReadableListening) === 0) {
       state[kState] |= kFlowing;
     } else {
       state[kState] &= ~kFlowing;
@@ -1214,8 +1219,8 @@ Readable.prototype.resume = function() {
 };
 
 function resume(stream, state) {
-  if (!state.resumeScheduled) {
-    state.resumeScheduled = true;
+  if ((state[kState] & kResumeScheduled) === 0) {
+    state[kState] |= kResumeScheduled;
     process.nextTick(resume_, stream, state);
   }
 }
@@ -1236,7 +1241,7 @@ function resume_(stream, state) {
 Readable.prototype.pause = function() {
   const state = this._readableState;
   debug('call pause');
-  if (state.flowing !== false) {
+  if ((state[kState] & (kHasFlowing | kFlowing)) !== kHasFlowing) {
     debug('pause');
     state[kState] |= kHasFlowing;
     state[kState] &= ~kFlowing;
@@ -1651,20 +1656,19 @@ function fromList(n, state) {
 function endReadable(stream) {
   const state = stream._readableState;
 
-  debug('endReadable', (state[kState] & kEndEmitted) !== 0);
+  debug('endReadable');
   if ((state[kState] & kEndEmitted) === 0) {
     state[kState] |= kEnded;
     process.nextTick(endReadableNT, state, stream);
   }
 }
 
 function endReadableNT(state, stream) {
-  debug('endReadableNT', state.endEmitted, state.length);
+  debug('endReadableNT');
 
   // Check that we didn't get one last unshift.
-  if (!state.errored && !state.closeEmitted &&
-      !state.endEmitted && state.length === 0) {
-    state.endEmitted = true;
+  if ((state[kState] & (kErrored | kCloseEmitted | kEndEmitted)) === 0 && state.length === 0) {
+    state[kState] |= kEndEmitted;
     stream.emit('end');
 
     if (stream.writable && stream.allowHalfOpen === false) {