stream: improve writable.write() performance

mscdex · MylesBorins · commit 1e05ddf406e6 · 2020-03-10T13:21:47.000-04:00
Backport-PR-URL: #32169 PR-URL: #31624 Reviewed-By: Matteo Collina <matteo.collina@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
diff --git a/lib/_stream_writable.js b/lib/_stream_writable.js
@@ -268,35 +268,8 @@ Writable.prototype.pipe = function() {
 };
 
 
-function writeAfterEnd(stream, cb) {
-  const er = new ERR_STREAM_WRITE_AFTER_END();
-  // TODO: defer error events consistently everywhere, not just the cb
-  errorOrDestroy(stream, er);
-  process.nextTick(cb, er);
-}
-
-// Checks that a user-supplied chunk is valid, especially for the particular
-// mode the stream is in. Currently this means that `null` is never accepted
-// and undefined/non-string values are only allowed in object mode.
-function validChunk(stream, state, chunk, cb) {
-  var er;
-
-  if (chunk === null) {
-    er = new ERR_STREAM_NULL_VALUES();
-  } else if (typeof chunk !== 'string' && !state.objectMode) {
-    er = new ERR_INVALID_ARG_TYPE('chunk', ['string', 'Buffer'], chunk);
-  }
-  if (er) {
-    errorOrDestroy(stream, er);
-    process.nextTick(cb, er);
-    return false;
-  }
-  return true;
-}
-
 Writable.prototype.write = function(chunk, encoding, cb) {
   const state = this._writableState;
-  var ret = false;
   const isBuf = !state.objectMode && Stream._isUint8Array(chunk);
 
   // Do not use Object.getPrototypeOf as it is slower since V8 7.3.
@@ -306,29 +279,42 @@ Writable.prototype.write = function(chunk, encoding, cb) {
 
   if (typeof encoding === 'function') {
     cb = encoding;
-    encoding = null;
+    encoding = state.defaultEncoding;
+  } else {
+    if (!encoding)
+      encoding = state.defaultEncoding;
+    if (typeof cb !== 'function')
+      cb = nop;
   }
 
   if (isBuf)
     encoding = 'buffer';
-  else if (!encoding)
-    encoding = state.defaultEncoding;
-
-  if (typeof cb !== 'function')
-    cb = nop;
 
+  let err;
   if (state.ending) {
-    writeAfterEnd(this, cb);
+    err = new ERR_STREAM_WRITE_AFTER_END();
   } else if (state.destroyed) {
-    const err = new ERR_STREAM_DESTROYED('write');
-    process.nextTick(cb, err);
-    errorOrDestroy(this, err);
-  } else if (isBuf || validChunk(this, state, chunk, cb)) {
-    state.pendingcb++;
-    ret = writeOrBuffer(this, state, chunk, encoding, cb);
+    err = new ERR_STREAM_DESTROYED('write');
+  } else if (chunk === null) {
+    err = new ERR_STREAM_NULL_VALUES();
+  } else {
+    if (!isBuf && !state.objectMode) {
+      if (typeof chunk !== 'string') {
+        err = new ERR_INVALID_ARG_TYPE('chunk', ['string', 'Buffer'], chunk);
+      } else if (encoding !== 'buffer' && state.decodeStrings !== false) {
+        chunk = Buffer.from(chunk, encoding);
+        encoding = 'buffer';
+      }
+    }
+    if (err === undefined) {
+      state.pendingcb++;
+      return writeOrBuffer(this, state, chunk, encoding, cb);
+    }
   }
 
-  return ret;
+  process.nextTick(cb, err);
+  errorOrDestroy(this, err, true);
+  return false;
 };
 
 Writable.prototype.cork = function() {
@@ -363,13 +349,6 @@ Writable.prototype.setDefaultEncoding = function setDefaultEncoding(encoding) {
 // in the queue, and wait our turn.  Otherwise, call _write
 // If we return false, then we need a drain event, so set that flag.
 function writeOrBuffer(stream, state, chunk, encoding, cb) {
-  if (!state.objectMode &&
-      state.decodeStrings !== false &&
-      encoding !== 'buffer' &&
-      typeof chunk === 'string') {
-    chunk = Buffer.from(chunk, encoding);
-    encoding = 'buffer';
-  }
   const len = state.objectMode ? 1 : chunk.length;
 
   state.length += len;
