further reduce heap allocations

soypat · Dec 31, 2023 · d7a45d2 · d7a45d2
1 parent 6a26e9d
commit d7a45d2
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Showing 4 changed files with 38 additions and 24 deletions.
diff --git a/httpx/header.go b/httpx/header.go
@@ -8,23 +8,27 @@ import (
 	"strings"
 )
 
+type ResponseHeader struct {
+	hdr header
+}
+
 type RequestHeader struct {
 	header
 }
 
 type header struct {
-	statusCode           int
-	contentLength        int
-	host                 []byte
-	contentLengthBytes   []byte
-	contentType          []byte
-	userAgent            []byte
-	method               []byte
-	proto                []byte
-	requestURI           []byte
-	rawHeaders           []byte
-	mulHeader            []byte
-	cookies              []argsKV
+	statusCode         int
+	contentLength      int
+	host               []byte
+	contentLengthBytes []byte
+	contentType        []byte
+	userAgent          []byte
+	method             []byte
+	proto              []byte
+	requestURI         []byte
+	rawHeaders         []byte
+	mulHeader          []byte
+
 	disableNormalizing   bool
 	disableSpecialHeader bool
 	noDefaultContentType bool
@@ -34,7 +38,9 @@ type header struct {
 	// Reusable buffer for building strings.
 	bufKV   argsKV
 	h       []argsKV
+	cookies []argsKV
 	trailer []argsKV
+	scanner headerScanner
 }
 
 func (h *header) SetContentRange(startPos, endPos, contentLength int) {

diff --git a/httpx/header_parse.go b/httpx/header_parse.go
@@ -130,8 +130,8 @@ func readRawHeaders(dst, buf []byte) ([]byte, int, error) {
 
 func (h *header) parseHeaders(buf []byte) (int, error) {
 	h.contentLength = -2
-
-	var s headerScanner
+	h.scanner = headerScanner{}
+	s := &h.scanner
 	s.b = buf
 	s.disableNormalizing = h.disableNormalizing
 	var err error

diff --git a/httpx/header_test.go b/httpx/header_test.go
@@ -15,7 +15,7 @@ func TestRequestHeaderEmptyValueFromString(t *testing.T) {
 		"Host: foobar\r\n" +
 		"EmptyValue2: \r\n" +
 		"\r\n"
-	var h header
+	var h RequestHeader
 	br := bufio.NewReader(bytes.NewBufferString(s))
 	if err := h.Read(br); err != nil {
 		t.Fatalf("unexpected error: %v", err)
@@ -42,7 +42,7 @@ func TestRequestRawHeaders(t *testing.T) {
 	t.Run("normalized", func(t *testing.T) {
 		s := "GET / HTTP/1.1\r\n" + kvs
 		exp := kvs
-		var h header
+		var h RequestHeader
 		br := bufio.NewReader(bytes.NewBufferString(s))
 		if err := h.Read(br); err != nil {
 			t.Fatalf("unexpected error: %v", err)
@@ -88,7 +88,7 @@ func TestRequestRawHeaders(t *testing.T) {
 	t.Run("http10", func(t *testing.T) {
 		s := "GET / HTTP/1.0\r\n" + kvs
 		exp := kvs
-		var h header
+		var h RequestHeader
 		br := bufio.NewReader(bytes.NewBufferString(s))
 		if err := h.Read(br); err != nil {
 			t.Fatalf("unexpected error: %v", err)
@@ -107,7 +107,7 @@ func TestRequestRawHeaders(t *testing.T) {
 	t.Run("no-kvs", func(t *testing.T) {
 		s := "GET / HTTP/1.1\r\n\r\n"
 		exp := ""
-		var h header
+		var h RequestHeader
 		h.DisableNormalizing()
 		br := bufio.NewReader(bytes.NewBufferString(s))
 		if err := h.Read(br); err != nil {
@@ -134,7 +134,7 @@ func TestRequestDisableSpecialHeaders(t *testing.T) {
 		"Non-Special: val\r\n" +
 		"\r\n"
 
-	var h header
+	var h RequestHeader
 	h.DisableSpecialHeader()
 
 	s := "GET / HTTP/1.0\r\n" + kvs

diff --git a/stacks/dhcp_client.go b/stacks/dhcp_client.go
@@ -34,7 +34,8 @@ type DHCPClient struct {
 	svip        [4]byte
 	requestedIP [4]byte
 	optionbuf   [4]dhcp.Option
-	msgbug      [1]byte
+	// This field is for avoiding heap allocations.
+	msgbug [2]byte
 }
 
 // State transition table:
@@ -214,13 +215,18 @@ func (d *DHCPClient) recv(pkt *UDPPacket) (err error) {
 	}
 
 	// Parse DHCP options looking for message type field.
-	var msgType dhcp.MessageType
-	debugEnabled := d.stack.isLogEnabled(slog.LevelDebug)
+	// var mt dhcp.MessageType
+	mt := &d.msgbug[0]
+	db := &d.msgbug[1]
+	*db = 0
+	if d.stack.isLogEnabled(slog.LevelDebug) {
+		*db = 1
+	}
 	err = dhcp.ForEachOption(incpayload, func(opt dhcp.Option) error {
 		switch opt.Num {
 		case dhcp.OptMessageType:
 			if len(opt.Data) == 1 {
-				msgType = dhcp.MessageType(opt.Data[0])
+				*mt = opt.Data[0]
 			}
 		// The DHCP server information does not have to be in the header, but can
 		// be in the options. Copy into the decoded header for simplicity.
@@ -229,11 +235,13 @@ func (d *DHCPClient) recv(pkt *UDPPacket) (err error) {
 				copy(rcvHdr.SIAddr[:], opt.Data)
 			}
 		}
-		if debugEnabled && !internal.HeapAllocDebugging {
+		if *db != 0 && !internal.HeapAllocDebugging {
 			d.stack.debug("DHCP:rx", slog.String("opt", opt.Num.String()), slog.String("data", stringNumList(opt.Data)))
 		}
 		return nil
 	})
+
+	msgType := dhcp.MessageType(*mt)
 	if d.stack.isLogEnabled(slog.LevelInfo) {
 		d.stack.info("DHCP:rx", slog.String("msg", msgType.String()))
 	}