perf: improve perf of parseRawHeaders (nodejs#2781)

benchmarks/parseRawHeaders.mjs

@@ -0,0 +1,24 @@
+import { bench, group, run } from 'mitata'
+import { parseRawHeaders } from '../lib/core/util.js'
+
+const rawHeadersMixed = ['key', 'value', Buffer.from('key'), Buffer.from('value')]
+const rawHeadersOnlyStrings = ['key', 'value', 'key', 'value']
+const rawHeadersOnlyBuffers = [Buffer.from('key'), Buffer.from('value'), Buffer.from('key'), Buffer.from('value')]
+const rawHeadersContent = ['content-length', 'value', 'content-disposition', 'form-data; name="fieldName"']
+
+group('parseRawHeaders', () => {
+  bench('only strings', () => {
+    parseRawHeaders(rawHeadersOnlyStrings)
+  })
+  bench('only buffers', () => {
+    parseRawHeaders(rawHeadersOnlyBuffers)
+  })
+  bench('mixed', () => {
+    parseRawHeaders(rawHeadersMixed)
+  })
+  bench('content-disposition special case', () => {
+    parseRawHeaders(rawHeadersContent)
+  })
+})
+
+await run()

lib/core/util.js

@@ -279,22 +279,30 @@ function parseHeaders (headers, obj) {
 }
 
 function parseRawHeaders (headers) {
-  const ret = []
+  const len = headers.length
+  const ret = new Array(len)
+
   let hasContentLength = false
   let contentDispositionIdx = -1
+  let key
+  let val
+  let kLen = 0
 
   for (let n = 0; n < headers.length; n += 2) {
-    const key = headers[n + 0].toString()
-    const val = headers[n + 1].toString('utf8')
+    key = headers[n]
+    val = headers[n + 1]
+
+    typeof key !== 'string' && (key = key.toString())
+    typeof val !== 'string' && (val = val.toString('utf8'))
 
-    if (key.length === 14 && (key === 'content-length' || key.toLowerCase() === 'content-length')) {
-      ret.push(key, val)
+    kLen = key.length
+    if (kLen === 14 && key[7] === '-' && (key === 'content-length' || key.toLowerCase() === 'content-length')) {
       hasContentLength = true
-    } else if (key.length === 19 && (key === 'content-disposition' || key.toLowerCase() === 'content-disposition')) {
-      contentDispositionIdx = ret.push(key, val) - 1
-    } else {
-      ret.push(key, val)
+    } else if (kLen === 19 && key[7] === '-' && (key === 'content-disposition' || key.toLowerCase() === 'content-disposition')) {
+      contentDispositionIdx = n + 1
     }
+    ret[n] = key
+    ret[n + 1] = val
   }
 
   // See https://github.com/nodejs/node/pull/46528

test/node-test/util.js

@@ -89,6 +89,7 @@ test('parseHeaders', () => {
 
 test('parseRawHeaders', () => {
   assert.deepEqual(util.parseRawHeaders(['key', 'value', Buffer.from('key'), Buffer.from('value')]), ['key', 'value', 'key', 'value'])
+  assert.deepEqual(util.parseRawHeaders(['content-length', 'value', 'content-disposition', 'form-data; name="fieldName"']), ['content-length', 'value', 'content-disposition', 'form-data; name="fieldName"'])
 })
 
 test('buildURL', () => {