massive documentation push and code reordering in files

examples/berkeley-listener/berkeley_server.go

@@ -288,7 +288,7 @@ func handleConnNet(conn net.Conn) error {
 		}
 	}
 	method := string(hdr.Method())
-	uri := string(hdr.RequestURI())
+	uri := string(hdr.RequestTarget())
 	fmt.Printf("< %s %s\n", method, uri)
 
 	var resp httpraw.Header
@@ -370,7 +370,7 @@ func mockClient(stack *xnet.StackAsync, port uint16, subnet netip.Prefix) {
 
 	var hdr httpraw.Header
 	hdr.SetMethod("GET")
-	hdr.SetRequestURI("/")
+	hdr.SetRequestTarget("/")
 	hdr.SetProtocol("HTTP/1.1")
 	hdr.Set("Host", string(ipv4.AppendFormatAddr(nil, stack.Addr4())))
 	hdr.Set("User-Agent", "lneto-mock")

examples/http-linux/main-httplinux.go

@@ -97,8 +97,8 @@ func homepage(exch *httphi.Exchange) {
 	n += len(strconv.AppendUint(page[n:n], visits.Add(1), 10))
 	n += copy(page[n:], htmlTail)
 
-	exch.SetHeader("Content-Type", "text/html")
-	exch.SetHeaderInt("Content-Length", int64(n), 10)
+	exch.StageHeader("Content-Type", "text/html")
+	exch.StageHeaderInt("Content-Length", int64(n), 10)
 	exch.WriteHeader(int(httphi.StatusOK))
 	exch.Write(page[:n])
 }

examples/httpclient/main.go

@@ -27,7 +27,7 @@ func run() error {
 	// Prepare GET request.
 	var hdr httpraw.Header
 	hdr.SetMethod("GET")
-	hdr.SetRequestURI("/")
+	hdr.SetRequestTarget("/")
 	hdr.SetProtocol("HTTP/1.1")
 	req, err := hdr.AppendRequest(nil)
 	if err != nil {

examples/httpserver/main.go

@@ -282,7 +282,7 @@ func handleConnection(conn *tcp.Conn) error {
 	}
 
 	method := string(hdr.Method())
-	uri := string(hdr.RequestURI())
+	uri := string(hdr.RequestTarget())
 	fmt.Printf("< %s %s\n", method, uri)
 
 	// Build response body.

examples/xcurl/main.go

@@ -307,7 +307,7 @@ func run() (err error) {
 	timeHTTPCreate := timer("create HTTP GET request")
 	var hdr httpraw.Header
 	hdr.SetMethod("GET")
-	hdr.SetRequestURI("/")
+	hdr.SetRequestTarget("/")
 	hdr.SetProtocol("HTTP/1.1")
 	hdr.Set("Host", flagHostToResolve)
 	hdr.Set("User-Agent", "lneto")

http/httphi/bench_test.go

@@ -61,8 +61,8 @@ func BenchmarkHandle(b *testing.B) {
 			name:    "GETWithHeadersAndQuery",
 			request: "GET /?abc=123 HTTP/1.1\r\nHost: tinygo.org\r\nUser-Agent: bench\r\nAccept: */*\r\nConnection: close\r\n\r\n",
 			handler: func(ex *Exchange) {
-				ex.SetHeader("Content-Type", "text/plain")
-				ex.SetHeaderInt("Content-Length", int64(len(benchBody)), 10)
+				ex.StageHeader("Content-Type", "text/plain")
+				ex.StageHeaderInt("Content-Length", int64(len(benchBody)), 10)
 				data, present := ex.AppendQuery(buf[:0], "abc", true)
 				if !present || !internal.BytesEqual(data, expect) {
 					panic("invalid result")

http/httphi/exchange.go

@@ -0,0 +1,380 @@
+package httphi
+
+import (
+	"slices"
+	"strconv"
+	"sync/atomic"
+
+	"github.com/soypat/lneto/http/httpraw"
+	"github.com/soypat/lneto/internal"
+)
+
+// maxStatusLine bounds the response status line: "HTTP/1.1 " + 3 digit code +
+// " " + longest [StatusText] + CRLF.
+const maxStatusLine = len("HTTP/1.1 ") + 3 + 1 + len("Network Authentication Required") + 2
+
+// Exchange is a single request-response cycle over a connection, playing the
+// part of both http.Request and http.ResponseWriter: Request* methods read the
+// request, [Exchange.StageHeader] and [Exchange.Write] produce the response.
+// A [Router] owns a fixed pool of them, which is what bounds its memory.
+//
+// Request and response share one buffer, the response header being written over
+// the bytes that follow the parsed request header. Read the request body with
+// [Exchange.ReadBody] before setting response headers.
+type Exchange struct {
+	used           atomic.Bool
+	respTopBuf     [maxStatusLine]byte
+	respTopWritten uint8
+
+	rawbuf        []byte
+	respHeaderOff uint16
+	respHeaderLen uint16
+	reqHdr        httpraw.Header
+
+	hijacked bool
+	rw       conn
+
+	respRemains   int
+	respErr       error // Sticky: response is unrecoverable once a write fails.
+	headerWritten bool
+	normalizeKeys bool
+	nextFree      *Exchange
+	readErr       error
+}
+
+// HijackRaw is a low-level implementation of http.Hijacker interface.
+// A Hijack method is not exposed due to heap allocation implications and correctness concerns.
+// Below is what an actual implementation may look like:
+//
+//	func (exch *Exchange) Hijack() (net.Conn, *bufio.ReadWriter, error) {
+//		conn, ok := exch.rw.(net.Conn)
+//		if !ok {
+//			return nil, nil, errors.New("net.Conn not implemented")
+//		}
+//		_, data, err := exch.HijackRaw(nil)
+//		if err != nil {
+//			return nil, nil, err
+//		}
+//		var rd *bufio.ReadWriter
+//		if len(data) > 0 {
+//			rd = &bufio.ReadWriter{Reader: bufio.NewReader(bytes.NewReader(data))}
+//		}
+//		return conn, rd, nil
+//	}
+func (exch *Exchange) HijackRaw(dstBody []byte) (conn, []byte, error) {
+	data, err := exch.remainingSurplusBody()
+	if err != nil {
+		return nil, nil, err
+	}
+	exch.hijacked = true
+	dstBody = append(dstBody, data...)
+	return exch.rw, dstBody, nil
+}
+
+// Configure sets the memory the exchange works with for the rest of its life:
+// rawbuf holds the request header, the response header and any surplus body,
+// of which the first requestLim bytes are reserved for the request header.
+// Panics if requestLim exceeds the buffer. Set normalizeKeys to normalize
+// outgoing header keys, i.e: "content-type" to "Content-Type".
+func (exch *Exchange) Configure(rawbuf []byte, requestLim int, normalizeKeys bool) {
+	respSize := len(rawbuf) - requestLim
+	if respSize < 0 {
+		panic("request lim larger than buffer")
+	}
+	exch.rawbuf = rawbuf
+	exch.reqHdr.Reset(rawbuf[:0:requestLim])
+	exch.normalizeKeys = normalizeKeys
+}
+
+// Acquire claims the exchange for conn and resets it to serve a new request,
+// reusing the buffer set by [Exchange.Configure]. Returns false if the exchange
+// is already serving, in which case conn is untouched.
+func (exch *Exchange) Acquire(conn conn) bool {
+	if !exch.used.CompareAndSwap(false, true) {
+		return false
+	}
+	exch.readErr = nil
+	exch.respErr = nil
+	exch.hijacked = false
+	exch.respTopWritten = 0
+	exch.respHeaderOff = 0
+	exch.respHeaderLen = 0
+	exch.respRemains = 0
+	exch.rw = conn
+	exch.headerWritten = false
+	exch.nextFree = nil
+	exch.reqHdr.Reset(nil)
+	return true
+}
+
+// Release closes the exchange's connection and frees the exchange for a future
+// [Exchange.Acquire]. The connection is left open if the handler took ownership
+// of it with [Exchange.HijackRaw].
+func (exch *Exchange) Release() {
+	if !exch.hijacked {
+		exch.rw.Close()
+	}
+	exch.rw = nil
+	exch.used.Store(false)
+}
+
+// StageHeader stages a response header field, written on the first
+// [Exchange.FlushHeader], [Exchange.WriteHeader] or [Exchange.Write].
+// Returns false and drops the field if the response buffer cannot fit it.
+// Has no effect once the header has been written.
+func (exch *Exchange) StageHeader(key, value string) (enoughMemory bool) {
+	if exch.headerWritten {
+		return false
+	}
+	off := int(exch.respHeaderOff) + int(exch.respHeaderLen)
+	free := len(exch.rawbuf) - off
+	// Field costs key+':'+value+CRLF, plus the CRLF [Exchange.FlushHeader]
+	// appends past the last field to close the header block.
+	if len(key)+len(value)+len(":\r\n")+len("\r\n") > free {
+		return false
+	}
+	n := copy(exch.rawbuf[off:], key)
+	if exch.normalizeKeys {
+		httpraw.NormalizeHeaderKey(exch.rawbuf[off : off+n])
+	}
+	exch.rawbuf[off+n] = ':'
+	n++
+	n += copy(exch.rawbuf[off+n:], value)
+	exch.rawbuf[off+n] = '\r'
+	exch.rawbuf[off+n+1] = '\n'
+	n += 2
+	exch.respHeaderLen += uint16(n)
+	return true
+}
+
+// StageHeaderInt is [Exchange.StageHeader] with an integer value, i.e: Content-Length.
+// It formats the value directly into the response buffer without allocating.
+// base must be in the range 10..36; lower bases are dropped, no HTTP header
+// field value is written below base 10.
+func (exch *Exchange) StageHeaderInt(key string, value int64, base int) (enoughMemory bool) {
+	if exch.headerWritten || base < 10 || base > 36 {
+		return false
+	}
+	off := int(exch.respHeaderOff) + int(exch.respHeaderLen)
+	free := len(exch.rawbuf) - off
+	if len(key)+internal.IntLen(value, base)+len(":\r\n")+len("\r\n") > free {
+		return false
+	}
+	n := copy(exch.rawbuf[off:], key)
+	if exch.normalizeKeys {
+		httpraw.NormalizeHeaderKey(exch.rawbuf[off : off+n])
+	}
+	exch.rawbuf[off+n] = ':'
+	n++
+	n += len(strconv.AppendInt(exch.rawbuf[off+n:off+n], value, base))
+	exch.rawbuf[off+n] = '\r'
+	exch.rawbuf[off+n+1] = '\n'
+	n += 2
+	exch.respHeaderLen += uint16(n)
+	return true
+}
+
+// StageWriteStatus prepares the status line for the given code without writing
+// it, i.e: "HTTP/1.1 404 Not Found". Codes with no [StatusText] get an empty
+// reason phrase. Has no effect once the header has been written.
+func (exch *Exchange) StageWriteStatus(code int) {
+	if code >= 1000 || exch.headerWritten {
+		return
+	} else if code == 200 {
+		// Common case.
+		exch.respTopWritten = uint8(copy(exch.respTopBuf[:], "HTTP/1.1 200 OK\r\n"))
+		return
+	}
+	n := copy(exch.respTopBuf[:], "HTTP/1.1 ")
+	n += len(strconv.AppendInt(exch.respTopBuf[n:n], int64(code), 10))
+	text := StatusText(code)
+	exch.respTopBuf[n] = ' '
+	n++
+	n += copy(exch.respTopBuf[n:], text)
+	exch.respTopBuf[n] = '\r'
+	exch.respTopBuf[n+1] = '\n'
+	exch.respTopWritten = uint8(n + 2)
+}
+
+// WriteHeader sends the status line for code along with the staged header
+// fields. Only the first call reaches the wire, as in http.ResponseWriter.
+func (exch *Exchange) WriteHeader(code int) {
+	if !exch.headerWritten {
+		exch.StageWriteStatus(code)
+		exch.FlushHeader()
+	}
+}
+
+// FlushHeader writes the status line and staged header fields to the connection
+// and returns the bytes written, defaulting to a 200 status if none was staged.
+// Does nothing if the header was already written.
+func (exch *Exchange) FlushHeader() (int, error) {
+	if exch.respErr != nil {
+		return 0, exch.respErr
+	} else if exch.headerWritten {
+		return 0, nil
+	}
+	if exch.respTopWritten == 0 {
+		exch.StageWriteStatus(200)
+	}
+	exch.headerWritten = true
+	ng, err := exch.rw.Write(exch.respTopBuf[:exch.respTopWritten])
+	if err != nil {
+		exch.respErr = err
+		return ng, err
+	}
+	off := int(exch.respHeaderOff)
+	headers := exch.rawbuf[off : off+int(exch.respHeaderLen)+2]
+	headers[len(headers)-1] = '\n'
+	headers[len(headers)-2] = '\r'
+	ng2, err := exch.rw.Write(headers)
+	exch.respErr = err
+	return ng + ng2, err
+}
+
+// Write writes response body bytes, flushing the header first if the handler
+// has not written it yet. Once a write to the connection fails the response is
+// unrecoverable and every later write returns that same error, so a body never
+// reaches the wire without its header.
+func (exch *Exchange) Write(buf []byte) (int, error) {
+	if exch.respErr != nil {
+		return 0, exch.respErr
+	} else if !exch.headerWritten {
+		_, err := exch.FlushHeader()
+		if err != nil {
+			return 0, err // Body must not reach the wire without its header.
+		}
+	}
+	if len(buf) == 0 {
+		return 0, nil
+	}
+	n, err := exch.rw.Write(buf)
+	exch.respErr = err
+	return n, err
+}
+
+// ReadBody reads the request body into dst, starting with the bytes that
+// arrived in the same read as the header and continuing from the connection.
+// The exchange does not know the body's length: use Content-Length or the
+// transfer encoding to know when to stop reading.
+func (exch *Exchange) ReadBody(dst []byte) (n int, _ error) {
+	if exch.respRemains > 0 {
+		toRead, err := exch.remainingSurplusBody()
+		if err != nil {
+			return 0, err
+		}
+		n = copy(dst, toRead)
+		exch.respRemains -= n
+		if len(dst) == n {
+			return n, nil
+		}
+		dst = dst[n:]
+	}
+	nr, err := exch.rw.Read(dst)
+	return nr + n, err
+}
+
+func (exch *Exchange) remainingSurplusBody() ([]byte, error) {
+	_, err := exch.reqHdr.Body()
+	if err != nil {
+		return nil, err // Returns mangled buffer error if request header has been misused.
+	}
+	surplus := exch.rawbuf[exch.reqHdr.BufferParsed():exch.reqHdr.BufferReceived()]
+	toRead := surplus[len(surplus)-exch.respRemains:]
+	return toRead, nil
+}
+
+// RequestHeaderRaw returns the parsed request header for access beyond the
+// Request* methods, such as [httpraw.Header.ForEach]. Valid until the exchange
+// is released, and writing to it corrupts the response.
+func (exch *Exchange) RequestHeaderRaw() *httpraw.Header {
+	return &exch.reqHdr
+}
+
+// RequestParseCookie parses the request's key header field into dst, i.e:
+// "Cookie". The caller owns dst and its buffer, so it may be reused between
+// requests.
+func (exch *Exchange) RequestParseCookie(dst *httpraw.Cookie, key string) error {
+	value := exch.RequestHeader(key)
+	return dst.ParseBytes(value)
+}
+
+// RequestHeader returns the value of the first request header field matching
+// key, or nil if absent. Key matching is case sensitive.
+func (exch *Exchange) RequestHeader(key string) []byte {
+	header := exch.RequestHeaderRaw()
+	return header.Get(key)
+}
+
+// RequestTarget returns the request-target (URI) of the request line, i.e:
+// "/search?q=go". See [httpraw.Header.RequestTarget].
+func (exch *Exchange) RequestTarget() []byte {
+	return exch.RequestHeaderRaw().RequestTarget()
+}
+
+// RequestPath returns the request-target (URI) up to the query string. This is
+// what the [Mux] matches on, i.e: "/search" for a request to "/search?q=go".
+func (exch *Exchange) RequestPath() []byte {
+	return exch.RequestHeaderRaw().RequestPath()
+}
+
+// RequestQuery returns the request's query string as it appears on the wire.
+// Iterate it with [httpraw.NextQueryPair]. See [httpraw.Header.RequestQuery].
+func (exch *Exchange) RequestQuery() []byte {
+	return exch.RequestHeaderRaw().RequestQuery()
+}
+
+// AppendQuery appends the value of the first query parameter matching key to
+// dst and reports whether the parameter was present. A parameter with no value
+// ("?debug") and one with an empty value ("?debug=") are both present with
+// nothing appended.
+//
+// Keys are matched decoded, so key "a b" finds "a%20b" and "a+b". Values are
+// appended raw unless decoded is set, in which case percent escapes and '+' are
+// decoded. A parameter whose value fails to decode is reported absent, and a
+// parameter whose key fails to decode is skipped.
+//
+// dst doubles as scratch space for decoding candidate keys, so AppendQuery only
+// allocates when dst lacks the capacity to hold the longest key it inspects.
+func (exch *Exchange) AppendQuery(dst []byte, key string, decoded bool) (valueAppended []byte, present bool) {
+	const plusAsSpace = true // Query strings are form encoded, unlike paths.
+	base := len(dst)
+	rawkey, rawval, rest := httpraw.NextQueryPair(exch.RequestQuery())
+	for ; rawkey != nil; rawkey, rawval, rest = httpraw.NextQueryPair(rest) {
+		if b2s(rawkey) != key {
+			// Key may be encoded: decode it over dst's free space and compare.
+			// A decoded key cannot appear raw, so this cannot alias a real key.
+			dst = slices.Grow(dst, len(rawkey))
+			scratch := dst[base : base+len(rawkey)]
+			n, err := httpraw.CopyDecodedPercentURL(scratch, rawkey, plusAsSpace)
+			if err != nil || b2s(scratch[:n]) != key {
+				continue // Malformed or different key, keep looking.
+			}
+		}
+		if len(rawval) == 0 {
+			return dst[:base], true // Flag or empty value, nothing to append.
+		}
+		dst = slices.Grow(dst, len(rawval))
+		if !decoded {
+			return append(dst[:base], rawval...), true
+		}
+		n, err := httpraw.CopyDecodedPercentURL(dst[base:base+len(rawval)], rawval, plusAsSpace)
+		if err != nil {
+			return dst[:base], false // Do not hand back half a decode.
+		}
+		return dst[:base+n], true
+	}
+	return dst[:base], false
+}
+
+// RequestMethod returns the request line's method, i.e: "GET". See
+// [MethodFromBytes] to compare it against a [Method].
+func (exch *Exchange) RequestMethod() []byte {
+	return exch.RequestHeaderRaw().Method()
+}
+
+// RequestConnectionClose returns true if the client asked for the connection to
+// be closed after this exchange with a "Connection: close" header field.
+func (exch *Exchange) RequestConnectionClose() bool {
+	return exch.RequestHeaderRaw().ConnectionClose()
+}

http/httphi/exchange_test.go

@@ -5,10 +5,11 @@ import (
 	"errors"
 	"strings"
 
-	"github.com/soypat/lneto/http/httpraw"
 	"testing"
 	"time"
 
+	"github.com/soypat/lneto/http/httpraw"
+
 	"github.com/soypat/lneto"
 )
 
@@ -122,7 +123,7 @@ func TestExchangeSetHeader(t *testing.T) {
 			conn := newConn("")
 			exch := newExchange(t, conn, 128, test.normalize)
 			for _, kv := range test.set {
-				if !exch.SetHeader(kv[0], kv[1]) {
+				if !exch.StageHeader(kv[0], kv[1]) {
 					t.Fatalf("SetHeader(%q,%q) reported insufficient memory", kv[0], kv[1])
 				}
 			}
@@ -144,7 +145,7 @@ func TestExchangeSetHeaderOOM(t *testing.T) {
 	const bufferSize = 32
 	conn := newConn("")
 	exch := newExchange(t, conn, bufferSize, false)
-	if exch.SetHeader("X-Big", strings.Repeat("v", 4*bufferSize)) {
+	if exch.StageHeader("X-Big", strings.Repeat("v", 4*bufferSize)) {
 		t.Fatal("want insufficient memory reported for oversized header value")
 	}
 	exch.WriteHeader(200)
@@ -195,7 +196,7 @@ func TestHandleRequestFields(t *testing.T) {
 			route, _, _ := strings.Cut(test.wantURI, "?") // Mux matches on path.
 			sm.Handle(route, func(ex *Exchange) {
 				gotMethod = string(ex.RequestMethod())
-				gotURI = string(ex.RequestURI())
+				gotURI = string(ex.RequestTarget())
 				gotHost = string(ex.RequestHeader("Host"))
 				ex.WriteHeader(200)
 			})
@@ -299,7 +300,7 @@ func TestExchangeSetHeaderExactFit(t *testing.T) {
 		if !exch.Acquire(conn) {
 			t.Fatal("fresh exchange failed to acquire connection")
 		}
-		set := exch.SetHeader(key, value)
+		set := exch.StageHeader(key, value)
 		exch.WriteHeader(200)
 
 		want := "HTTP/1.1 200 OK\r\n"
@@ -437,7 +438,7 @@ func TestExchangeSetHeaderInt(t *testing.T) {
 	} {
 		conn := newConn("")
 		exch := newExchange(t, conn, 256, false)
-		exch.SetHeaderInt("N", test.value, test.base)
+		exch.StageHeaderInt("N", test.value, test.base)
 		exch.WriteHeader(200)
 		got, _ := strings.CutPrefix(conn.ViewWritten(), "HTTP/1.1 200 OK\r\n")
 		if got != test.want {
@@ -450,7 +451,7 @@ func TestExchangeSetHeaderInt(t *testing.T) {
 func TestExchangeSetHeaderIntNoAlloc(t *testing.T) {
 	exch := newExchange(t, newConn(""), 256, false)
 	allocs := testing.AllocsPerRun(100, func() {
-		exch.SetHeaderInt("Content-Length", 1234567890, 10)
+		exch.StageHeaderInt("Content-Length", 1234567890, 10)
 	})
 	if allocs != 0 {
 		t.Errorf("SetHeaderInt allocated %v times, want 0", allocs)

http/httphi/httphi.go

@@ -1,709 +0,0 @@
-package httphi
-
-import (
-	"errors"
-	"io"
-	"log/slog"
-	"slices"
-	"strconv"
-	"sync"
-	"sync/atomic"
-	"time"
-	"unsafe"
-
-	"github.com/soypat/lneto"
-	"github.com/soypat/lneto/http/httpraw"
-	"github.com/soypat/lneto/internal"
-)
-
-//go:generate stringer -type Method,status -linecomment -output stringers.go
-
-// reconfigureWait bounds how long [Router.Configure] waits for the previous
-// generation to stop serving before reusing its exchange buffers.
-const reconfigureWait = 10 * time.Millisecond
-
-var (
-	errNoRequestProto = errors.New("httphi: request line with no HTTP version")
-	errBusyExchanges  = errors.New("httphi: exchanges still serving, cannot reuse their buffers")
-)
-
-type conn = io.ReadWriteCloser
-
-// Router hosts concurrent safe data.
-type Router struct {
-	mu            sync.Mutex
-	gen           atomic.Uint32
-	numGoro       int
-	reqBuf        int
-	respBuf       int
-	normalizeKeys bool
-	pendingConns  chan job
-	mux           Mux
-
-	globbuf  []byte
-	exchs    []Exchange
-	freeList *Exchange
-
-	backoff lneto.BackoffStrategy
-	log     *slog.Logger
-}
-
-type job struct {
-	exch *Exchange
-}
-
-type RouterConfig struct {
-	// FixedNumGoroutines must be set to either -1 (freely allocate new goroutines) or to the number of goroutines
-	// to spawn on [Router.Configure] being called.
-	FixedNumGoroutines int
-	// RequestBufferSize determines the buffer allocated
-	// for processing requests.
-	RequestBufferSize int
-	// ResponseMinBufferSize determines buffer allocated for processing responses.
-	// Response buffer will reuse unused request memory so this is not a strict limit.
-	ResponseMinBufferSize int
-
-	NormalizeOutgoingKeys bool
-	MaxAwaitingConns      int
-
-	Backoff lneto.BackoffStrategy
-	Mux     Mux
-	Logger  *slog.Logger
-}
-
-func (cfg RouterConfig) Validate() error {
-	workerMode := cfg.workerMode()
-	if workerMode && cfg.MaxAwaitingConns == 0 ||
-		cfg.Mux == nil ||
-		!workerMode && cfg.FixedNumGoroutines != -1 {
-		return lneto.ErrInvalidConfig
-	} else if cfg.Backoff == nil {
-		return lneto.ErrMissingHALConfig
-	}
-	return nil
-}
-
-func (cfg RouterConfig) workerMode() bool {
-	return cfg.FixedNumGoroutines > 0
-}
-
-// Teardown stops fixed goroutines.
-func (r *Router) TeardownGoroutines() {
-	r.mu.Lock()
-	defer r.mu.Unlock()
-	r.teardownGoroutinesLocked()
-}
-
-// teardownGoroutinesLocked closes the job queue fixed goroutines feed from.
-// Requires r.mu held so that a concurrent [Router.Handle] cannot be enqueueing
-// on the channel being closed.
-func (r *Router) teardownGoroutinesLocked() {
-	r.gen.Add(1)
-	if r.pendingConns != nil {
-		close(r.pendingConns)
-		r.pendingConns = nil
-	}
-}
-
-func (r *Router) Configure(cfg RouterConfig) error {
-	if err := cfg.Validate(); err != nil {
-		return err
-	}
-	r.mu.Lock()
-	defer r.mu.Unlock()
-	r.teardownGoroutinesLocked()
-	gen := r.gen.Load()
-	numgoro := cfg.FixedNumGoroutines
-	workerMode := cfg.workerMode()
-	r.reqBuf = cfg.RequestBufferSize
-	r.respBuf = cfg.ResponseMinBufferSize
-	r.mux = cfg.Mux
-	r.log = cfg.Logger
-	r.normalizeKeys = cfg.NormalizeOutgoingKeys
-	if !workerMode {
-		r.backoff = cfg.Backoff
-		r.numGoro = 0
-		r.pendingConns = nil
-		return nil
-	}
-	if workerMode {
-		jobqueue := make(chan job, cfg.MaxAwaitingConns)
-		if gen > 1 {
-			// Exchange buffers below are reused: the previous generation must be
-			// done serving before they may be handed to the new one.
-			err := r.awaitIdleExchangesLocked(reconfigureWait)
-			if err != nil {
-				return err
-			}
-		}
-		r.freeList = nil // Freelist entries point into the buffers reused below.
-		internal.SliceReuse(&r.exchs, numgoro)
-		r.exchs = r.exchs[:numgoro]
-		rawBuflen := cfg.RequestBufferSize + cfg.ResponseMinBufferSize
-		internal.SliceReuse(&r.globbuf, numgoro*rawBuflen)
-		for i := range numgoro {
-			// TODO exchange buffer alloc
-			goff := i * rawBuflen
-			r.exchs[i].Configure(r.globbuf[goff:goff+rawBuflen], cfg.RequestBufferSize, cfg.NormalizeOutgoingKeys)
-			go r.goroWorker(gen, jobqueue, cfg.Backoff, cfg.Mux)
-		}
-		r.pendingConns = jobqueue
-		r.numGoro = numgoro
-	}
-	return nil
-}
-
-// awaitIdleExchangesLocked waits up to maxWait for exchanges of the previous
-// generation to finish serving so their buffers may be reused. Requires r.mu
-// held; the lock is released while waiting since [Router.freeExch] needs it to
-// free the exchanges being waited on.
-func (r *Router) awaitIdleExchangesLocked(maxWait time.Duration) error {
-	const pollInterval = time.Millisecond
-	for waited := time.Duration(0); ; waited += pollInterval {
-		busy := false
-		for i := range r.exchs {
-			if r.exchs[i].used.Load() {
-				busy = true
-				break
-			}
-		}
-		if !busy {
-			return nil
-		} else if waited >= maxWait {
-			return errBusyExchanges
-		}
-		r.mu.Unlock()
-		time.Sleep(pollInterval)
-		r.mu.Lock()
-	}
-}
-
-// Handle is a extremely low-level HTTP handling method used internally in [Router].
-// Requires exchange to be acquired and configured. Will panic if any argument is nil.
-// Handle does not close the connection on any outcome: the caller owns it.
-func Handle(exch *Exchange, mux Mux, backoff lneto.BackoffStrategy) error {
-	reqhdr := &exch.reqHdr
-	reqhdr.Reset(nil)
-	var consecutiveBackoffs uint
-	for {
-		n, err := reqhdr.ReadFromLimited(exch.rw, reqhdr.BufferFree())
-		if err != nil {
-			exch.readErr = err
-			return err
-		} else if n == 0 {
-			backoff.Do(consecutiveBackoffs)
-			consecutiveBackoffs++
-			continue
-		}
-		consecutiveBackoffs = 0
-		const asRequest = false
-		needMore, err := reqhdr.TryParse(asRequest)
-		if needMore {
-			continue // Request header split across reads, accumulate the rest.
-		} else if err != nil {
-			return err
-		}
-		break // Done!
-	}
-	// Setup Exchange fields necessary for correct functioning.
-	parsed := reqhdr.BufferParsed()
-	exch.respRemains = reqhdr.BufferReceived() - parsed
-	exch.respHeaderOff = uint16(parsed)
-	exch.respHeaderLen = 0
-	if len(reqhdr.Protocol()) == 0 {
-		// Request line with no HTTP version is a HTTP/0.9 simple-request, which
-		// httpraw tolerates. It is not a valid HTTP/1.1 request-line, RFC 9112 3.
-		exch.WriteHeader(int(StatusBadRequest))
-		return errNoRequestProto
-	}
-	// Mux on the request path: the query string is the handler's business.
-	path := reqhdr.RequestPath()
-	meth := reqhdr.Method()
-	handler := mux.LookupHandler(MethodFromBytes(meth), path)
-	if handler != nil {
-		handler(exch)
-		exch.FlushHeader()
-	} else {
-		exch.WriteHeader(404)
-	}
-	// TODO write response from exchange here.
-	return nil
-}
-
-func (r *Router) Handle(conn conn) error {
-	// Exchange acquisition and the configuration it is served with must be read
-	// under the same lock: [Router.Configure] may run concurrently.
-	r.mu.Lock()
-	exch := r.getExchLocked(conn)
-	numGoro, backoff, mux := r.numGoro, r.backoff, r.mux
-	if exch == nil {
-		r.mu.Unlock()
-		return lneto.ErrExhausted
-	} else if numGoro == 0 {
-		r.mu.Unlock()
-		go r.goroHandle(exch, backoff, mux)
-		return nil
-	}
-	// Enqueue under the lock: [Router.Configure] closes pendingConns while
-	// holding it, so an unlocked send could land on a closed channel. The send
-	// never blocks, so holding the lock cannot stall a worker.
-	var enqueued bool
-	select {
-	case r.pendingConns <- job{exch: exch}:
-		enqueued = true
-	default:
-		// pendingConns cannot store another Conn, we drop and return error.
-		exch.used.Store(false) // release.
-	}
-	r.mu.Unlock()
-	if enqueued {
-		return nil
-	}
-	return lneto.ErrPacketDrop
-}
-
-func (r *Router) goroWorker(gen uint32, queue chan job, backoff lneto.BackoffStrategy, mux Mux) {
-	for job := range queue {
-		exch := job.exch
-		if gen != r.gen.Load() {
-			return
-		} else if exch == nil {
-			panic("httplo: unreachable nil job")
-		}
-		r.goroHandle(exch, backoff, mux)
-	}
-}
-
-func (r *Router) goroHandle(exch *Exchange, backoff lneto.BackoffStrategy, mux Mux) {
-	defer r.freeExch(exch)
-	err := Handle(exch, mux, backoff)
-	if err != nil {
-		if exch.readErr != nil {
-			r.error("goroHandle:ReadFromLimited", slog.String("err", err.Error()))
-		} else {
-			r.error("goroHandle:TryParse?", slog.String("err", err.Error()))
-		}
-	}
-}
-
-func (r *Router) freeExch(exch *Exchange) {
-	const freelistMaxDepth = 5
-	r.mu.Lock()
-	depth := 0
-	for node := r.freeList; node != nil && depth < freelistMaxDepth; node = node.nextFree {
-		depth++
-	}
-	if depth < freelistMaxDepth {
-		// Push at head: appending at the tail would drop every node past the
-		// depth limit instead of dropping the exchange we cannot store.
-		exch.nextFree = r.freeList
-		r.freeList = exch
-	} else {
-		exch.nextFree = nil // Freelist full, exchange is dropped.
-	}
-	exch.Release()
-	r.mu.Unlock()
-}
-
-// getExchLocked returns an exchange acquired on conn. Requires r.mu held.
-func (r *Router) getExchLocked(conn conn) (exch *Exchange) {
-	if r.freeList != nil {
-		// Successor must be read before Acquire: Acquire clears nextFree, so
-		// popping afterwards would truncate the freelist to the popped node.
-		next := r.freeList.nextFree
-		if r.freeList.Acquire(conn) {
-			exch = r.freeList
-			r.freeList = next
-			return exch
-		}
-	}
-	for i := range r.exchs {
-		if r.exchs[i].Acquire(conn) {
-			return &r.exchs[i]
-		}
-	}
-
-	if r.numGoro == 0 {
-		exch := new(Exchange)
-		exch.Configure(make([]byte, r.respBuf+r.reqBuf), r.reqBuf, r.normalizeKeys)
-		exch.Acquire(conn) // Fresh exchange, CAS cannot fail.
-		return exch
-	}
-	return nil
-}
-
-func (r *Router) error(msg string, attrs ...slog.Attr) {
-	internal.LogAttrs(r.log, slog.LevelError, msg, attrs...)
-}
-
-func (r *Router) info(msg string, attrs ...slog.Attr) {
-	internal.LogAttrs(r.log, slog.LevelInfo, msg, attrs...)
-}
-
-// maxStatusLine bounds the response status line: "HTTP/1.1 " + 3 digit code +
-// " " + longest [StatusText] + CRLF.
-const maxStatusLine = len("HTTP/1.1 ") + 3 + 1 + len("Network Authentication Required") + 2
-
-type Exchange struct {
-	used           atomic.Bool
-	respTopBuf     [maxStatusLine]byte
-	respTopWritten uint8
-
-	rawbuf        []byte
-	respHeaderOff uint16
-	respHeaderLen uint16
-	reqHdr        httpraw.Header
-
-	hijacked bool
-	rw       conn
-
-	respRemains   int
-	respErr       error // Sticky: response is unrecoverable once a write fails.
-	headerWritten bool
-	normalizeKeys bool
-	nextFree      *Exchange
-	readErr       error
-}
-
-// HijackRaw is a low-level implementation of http.Hijacker interface.
-// A Hijack method is not exposed due to heap allocation implications and correctness concerns.
-// Below is what an actual implementation may look like:
-//
-//	func (exch *Exchange) Hijack() (net.Conn, *bufio.ReadWriter, error) {
-//		conn, ok := exch.rw.(net.Conn)
-//		if !ok {
-//			return nil, nil, errors.New("net.Conn not implemented")
-//		}
-//		_, data, err := exch.HijackRaw(nil)
-//		if err != nil {
-//			return nil, nil, err
-//		}
-//		var rd *bufio.ReadWriter
-//		if len(data) > 0 {
-//			rd = &bufio.ReadWriter{Reader: bufio.NewReader(bytes.NewReader(data))}
-//		}
-//		return conn, rd, nil
-//	}
-func (exch *Exchange) HijackRaw(dstBody []byte) (conn, []byte, error) {
-	data, err := exch.remainingSurplusBody()
-	if err != nil {
-		return nil, nil, err
-	}
-	exch.hijacked = true
-	dstBody = append(dstBody, data...)
-	return exch.rw, dstBody, nil
-}
-
-func (exch *Exchange) Configure(rawbuf []byte, requestLim int, normalizeKeys bool) {
-	respSize := len(rawbuf) - requestLim
-	if respSize < 0 {
-		panic("request lim larger than buffer")
-	}
-	exch.rawbuf = rawbuf
-	exch.reqHdr.Reset(rawbuf[:0:requestLim])
-	exch.normalizeKeys = normalizeKeys
-}
-
-func (exch *Exchange) Acquire(conn conn) bool {
-	if !exch.used.CompareAndSwap(false, true) {
-		return false
-	}
-	exch.readErr = nil
-	exch.respErr = nil
-	exch.hijacked = false
-	exch.respTopWritten = 0
-	exch.respHeaderOff = 0
-	exch.respHeaderLen = 0
-	exch.respRemains = 0
-	exch.rw = conn
-	exch.headerWritten = false
-	exch.nextFree = nil
-	exch.reqHdr.Reset(nil)
-	return true
-}
-
-func (exch *Exchange) Release() {
-	if !exch.hijacked {
-		exch.rw.Close()
-	}
-	exch.rw = nil
-	exch.used.Store(false)
-}
-
-func (exch *Exchange) SetHeader(key, value string) (enoughMemory bool) {
-	off := int(exch.respHeaderOff) + int(exch.respHeaderLen)
-	free := len(exch.rawbuf) - off
-	// Field costs key+':'+value+CRLF, plus the CRLF [Exchange.FlushHeader]
-	// appends past the last field to close the header block.
-	if len(key)+len(value)+len(":\r\n")+len("\r\n") > free {
-		return false
-	}
-	n := copy(exch.rawbuf[off:], key)
-	if exch.normalizeKeys {
-		httpraw.NormalizeHeaderKey(exch.rawbuf[off : off+n])
-	}
-	exch.rawbuf[off+n] = ':'
-	n++
-	n += copy(exch.rawbuf[off+n:], value)
-	exch.rawbuf[off+n] = '\r'
-	exch.rawbuf[off+n+1] = '\n'
-	n += 2
-	exch.respHeaderLen += uint16(n)
-	return true
-}
-
-// SetHeaderInt is [Exchange.SetHeader] with an integer value, i.e: Content-Length.
-// It formats the value directly into the response buffer without allocating.
-// base must be in the range 10..36; lower bases are dropped, no HTTP header
-// field value is written below base 10.
-func (exch *Exchange) SetHeaderInt(key string, value int64, base int) (enoughMemory bool) {
-	if base < 10 || base > 36 {
-		return false
-	}
-	off := int(exch.respHeaderOff) + int(exch.respHeaderLen)
-	free := len(exch.rawbuf) - off
-	if len(key)+internal.IntLen(value, base)+len(":\r\n")+len("\r\n") > free {
-		return false
-	}
-	n := copy(exch.rawbuf[off:], key)
-	if exch.normalizeKeys {
-		httpraw.NormalizeHeaderKey(exch.rawbuf[off : off+n])
-	}
-	exch.rawbuf[off+n] = ':'
-	n++
-	n += len(strconv.AppendInt(exch.rawbuf[off+n:off+n], value, base))
-	exch.rawbuf[off+n] = '\r'
-	exch.rawbuf[off+n+1] = '\n'
-	n += 2
-	exch.respHeaderLen += uint16(n)
-	return true
-}
-
-func (exch *Exchange) StageWriteStatus(code int) {
-	if code >= 1000 || exch.headerWritten {
-		return
-	} else if code == 200 {
-		// Common case.
-		exch.respTopWritten = uint8(copy(exch.respTopBuf[:], "HTTP/1.1 200 OK\r\n"))
-		return
-	}
-	n := copy(exch.respTopBuf[:], "HTTP/1.1 ")
-	n += len(strconv.AppendInt(exch.respTopBuf[n:n], int64(code), 10))
-	text := StatusText(code)
-	exch.respTopBuf[n] = ' '
-	n++
-	n += copy(exch.respTopBuf[n:], text)
-	exch.respTopBuf[n] = '\r'
-	exch.respTopBuf[n+1] = '\n'
-	exch.respTopWritten = uint8(n + 2)
-}
-
-func (exch *Exchange) WriteHeader(code int) {
-	if !exch.headerWritten {
-		exch.StageWriteStatus(code)
-		exch.FlushHeader()
-	}
-}
-func (exch *Exchange) FlushHeader() (int, error) {
-	if exch.respErr != nil {
-		return 0, exch.respErr
-	} else if exch.headerWritten {
-		return 0, nil
-	}
-	if exch.respTopWritten == 0 {
-		exch.StageWriteStatus(200)
-	}
-	exch.headerWritten = true
-	ng, err := exch.rw.Write(exch.respTopBuf[:exch.respTopWritten])
-	if err != nil {
-		exch.respErr = err
-		return ng, err
-	}
-	off := int(exch.respHeaderOff)
-	headers := exch.rawbuf[off : off+int(exch.respHeaderLen)+2]
-	headers[len(headers)-1] = '\n'
-	headers[len(headers)-2] = '\r'
-	ng2, err := exch.rw.Write(headers)
-	exch.respErr = err
-	return ng + ng2, err
-}
-
-func (exch *Exchange) Write(buf []byte) (int, error) {
-	if exch.respErr != nil {
-		return 0, exch.respErr
-	} else if !exch.headerWritten {
-		_, err := exch.FlushHeader()
-		if err != nil {
-			return 0, err // Body must not reach the wire without its header.
-		}
-	}
-	if len(buf) == 0 {
-		return 0, nil
-	}
-	n, err := exch.rw.Write(buf)
-	exch.respErr = err
-	return n, err
-}
-
-func (exch *Exchange) ReadBody(dst []byte) (n int, _ error) {
-	if exch.respRemains > 0 {
-		toRead, err := exch.remainingSurplusBody()
-		if err != nil {
-			return 0, err
-		}
-		n = copy(dst, toRead)
-		exch.respRemains -= n
-		if len(dst) == n {
-			return n, nil
-		}
-		dst = dst[n:]
-	}
-	nr, err := exch.rw.Read(dst)
-	return nr + n, err
-}
-
-func (exch *Exchange) remainingSurplusBody() ([]byte, error) {
-	_, err := exch.reqHdr.Body()
-	if err != nil {
-		return nil, err // Returns mangled buffer error if request header has been misused.
-	}
-	surplus := exch.rawbuf[exch.reqHdr.BufferParsed():exch.reqHdr.BufferReceived()]
-	toRead := surplus[len(surplus)-exch.respRemains:]
-	return toRead, nil
-}
-
-func (exch *Exchange) RequestHeaderRaw() *httpraw.Header {
-	return &exch.reqHdr
-}
-
-func (exch *Exchange) RequestParseCookie(dst *httpraw.Cookie, key string) error {
-	value := exch.RequestHeader(key)
-	return dst.ParseBytes(value)
-}
-
-func (exch *Exchange) RequestHeader(key string) []byte {
-	header := exch.RequestHeaderRaw()
-	return header.Get(key)
-}
-
-func (exch *Exchange) RequestURI() []byte {
-	return exch.RequestHeaderRaw().RequestURI()
-}
-
-// RequestPath returns the request URI up to the query string. This is what the
-// [Mux] matches on, i.e: "/search" for a request to "/search?q=go".
-func (exch *Exchange) RequestPath() []byte {
-	return exch.RequestHeaderRaw().RequestPath()
-}
-
-// RequestQuery returns the request's query string as it appears on the wire.
-// Iterate it with [httpraw.NextQueryPair]. See [httpraw.Header.RequestQuery].
-func (exch *Exchange) RequestQuery() []byte {
-	return exch.RequestHeaderRaw().RequestQuery()
-}
-
-// AppendQuery appends the value of the first query parameter matching key to
-// dst and reports whether the parameter was present. A parameter with no value
-// ("?debug") and one with an empty value ("?debug=") are both present with
-// nothing appended.
-//
-// Keys are matched decoded, so key "a b" finds "a%20b" and "a+b". Values are
-// appended raw unless decoded is set, in which case percent escapes and '+' are
-// decoded. A parameter whose value fails to decode is reported absent, and a
-// parameter whose key fails to decode is skipped.
-//
-// dst doubles as scratch space for decoding candidate keys, so AppendQuery only
-// allocates when dst lacks the capacity to hold the longest key it inspects.
-func (exch *Exchange) AppendQuery(dst []byte, key string, decoded bool) (valueAppended []byte, present bool) {
-	const plusAsSpace = true // Query strings are form encoded, unlike paths.
-	base := len(dst)
-	rawkey, rawval, rest := httpraw.NextQueryPair(exch.RequestQuery())
-	for ; rawkey != nil; rawkey, rawval, rest = httpraw.NextQueryPair(rest) {
-		if b2s(rawkey) != key {
-			// Key may be encoded: decode it over dst's free space and compare.
-			// A decoded key cannot appear raw, so this cannot alias a real key.
-			dst = slices.Grow(dst, len(rawkey))
-			scratch := dst[base : base+len(rawkey)]
-			n, err := httpraw.CopyDecodedPercentURL(scratch, rawkey, plusAsSpace)
-			if err != nil || b2s(scratch[:n]) != key {
-				continue // Malformed or different key, keep looking.
-			}
-		}
-		if len(rawval) == 0 {
-			return dst[:base], true // Flag or empty value, nothing to append.
-		}
-		dst = slices.Grow(dst, len(rawval))
-		if !decoded {
-			return append(dst[:base], rawval...), true
-		}
-		n, err := httpraw.CopyDecodedPercentURL(dst[base:base+len(rawval)], rawval, plusAsSpace)
-		if err != nil {
-			return dst[:base], false // Do not hand back half a decode.
-		}
-		return dst[:base+n], true
-	}
-	return dst[:base], false
-}
-
-func (exch *Exchange) RequestMethod() []byte {
-	return exch.RequestHeaderRaw().Method()
-}
-
-func (exch *Exchange) RequestConnectionClose() bool {
-	return exch.RequestHeaderRaw().ConnectionClose()
-}
-
-type HandlerFunc func(ex *Exchange)
-
-type Method uint8
-
-const (
-	MethUndefined Method = iota // undefined
-	MethGet                     // GET
-	// lol.
-	MethHead // HEAD
-	MethPost // POST
-	MethPut  // PUT
-	// RFC 5789
-	MethPatch   // PATCH
-	MethDelete  // DELETE
-	MethConnect // CONNECT
-	MethOptions // OPTIONS
-	MethTrace   // TRACE
-	MethUnknown // unknown
-)
-
-func MethodFromBytes(meth []byte) (res Method) {
-	if len(meth) == 0 {
-		return MethUndefined
-	}
-	switch unsafe.String(&meth[0], len(meth)) {
-	case "GET":
-		res = MethGet
-	case "HEAD":
-		res = MethHead
-	case "POST":
-		res = MethPost
-	case "PUT":
-		res = MethPut
-	case "PATCH":
-		res = MethPatch
-	case "DELETE":
-		res = MethDelete
-	case "CONNECT":
-		res = MethConnect
-	case "OPTIONS":
-		res = MethOptions
-	case "TRACE":
-		res = MethTrace
-	default:
-		res = MethUnknown
-	}
-	return res
-}
-
-// b2s converts byte slice to a string without memory allocation.
-// See https://groups.google.com/forum/#!msg/Golang-Nuts/ENgbUzYvCuU/90yGx7GUAgAJ .
-func b2s(b []byte) string {
-	return unsafe.String(unsafe.SliceData(b), len(b))
-}

http/httphi/mux.go

@@ -2,50 +2,179 @@ package httphi
 
 import (
 	"strings"
+	"unsafe"
 
+	"github.com/soypat/lneto"
 	"github.com/soypat/lneto/internal"
 )
 
+// Handle is a extremely low-level HTTP handling method used internally in [Router].
+// Requires exchange to be acquired and configured. Will panic if any argument is nil.
+// Handle does not close the connection on any outcome: the caller owns it.
+func Handle(exch *Exchange, mux Mux, backoff lneto.BackoffStrategy) error {
+	reqhdr := &exch.reqHdr
+	reqhdr.Reset(nil)
+	var consecutiveBackoffs uint
+	for {
+		n, err := reqhdr.ReadFromLimited(exch.rw, reqhdr.BufferFree())
+		if err != nil {
+			exch.readErr = err
+			return err
+		} else if n == 0 {
+			backoff.Do(consecutiveBackoffs)
+			consecutiveBackoffs++
+			continue
+		}
+		consecutiveBackoffs = 0
+		const asRequest = false
+		needMore, err := reqhdr.TryParse(asRequest)
+		if needMore {
+			continue // Request header split across reads, accumulate the rest.
+		} else if err != nil {
+			return err
+		}
+		break // Done!
+	}
+	// Setup Exchange fields necessary for correct functioning.
+	parsed := reqhdr.BufferParsed()
+	exch.respRemains = reqhdr.BufferReceived() - parsed
+	exch.respHeaderOff = uint16(parsed)
+	exch.respHeaderLen = 0
+	if len(reqhdr.Protocol()) == 0 {
+		// Request line with no HTTP version is a HTTP/0.9 simple-request, which
+		// httpraw tolerates. It is not a valid HTTP/1.1 request-line, RFC 9112 3.
+		exch.WriteHeader(int(StatusBadRequest))
+		return errNoRequestProto
+	}
+	// Mux on the request path: the query string is the handler's business.
+	path := reqhdr.RequestPath()
+	meth := reqhdr.Method()
+	handler := mux.LookupHandler(MethodFromBytes(meth), path)
+	if handler != nil {
+		handler(exch)
+		exch.FlushHeader()
+	} else {
+		exch.WriteHeader(404)
+	}
+	// TODO write response from exchange here.
+	return nil
+}
+
+// HandlerFunc serves a single request, playing the part of http.Handler.
+// The exchange is only valid for the duration of the call: it is released to
+// the router's pool on return, so a handler must not retain it nor any slice it
+// handed out.
+type HandlerFunc func(ex *Exchange)
+
+// Mux resolves a request to the handler that serves it. [Handle] calls
+// LookupHandler with the request-target's path, not the whole target, and
+// replies 404 when it returns nil.
 type Mux interface {
 	LookupHandler(get Method, uri []byte) HandlerFunc
 }
 
+// MuxSlice is a [Mux] backed by a slice of registered endpoints, matched by
+// exact path. Lookup is linear in the number of registrations.
 type MuxSlice struct {
 	// TODO: binary search worth it?
 	_handlers []struct {
 		method  Method
-		uri     string
+		path    string
 		handler HandlerFunc
 	}
 }
 
+// Reset discards all registered handlers, reusing the backing array and growing
+// it to fit capacity registrations.
 func (sm *MuxSlice) Reset(capacity int) {
 	internal.SliceReuse(&sm._handlers, capacity)
 }
 
-func (sm *MuxSlice) LookupHandler(method Method, uri []byte) HandlerFunc {
+// LookupHandler returns the handler registered for request path, or nil if none matches.
+// The first registration matching both method and uri wins.
+func (sm *MuxSlice) LookupHandler(method Method, path []byte) HandlerFunc {
 	for _, endpoint := range sm._handlers {
 		if endpoint.method != MethUndefined && endpoint.method != method {
 			continue
 		}
 		// Method matches.
-		if b2s(uri) == endpoint.uri {
+		if b2s(path) == endpoint.path {
 			return endpoint.handler
 		}
 	}
 	return nil
 }
 
-func (sm *MuxSlice) Handle(reg string, handler HandlerFunc) {
+// Handle registers handler for reg, either a bare path matching any method or a
+// method and path separated by a space, i.e: "/health" or "GET /health".
+// Handle does not check for duplicate registrations: the first one added wins.
+func (sm *MuxSlice) Handle(optMethodAndPath string, handler HandlerFunc) {
 	v := internal.SliceReclaim(&sm._handlers)
 	method := MethUndefined
-	methodOrURL, url, methodFound := strings.Cut(reg, " ")
+	methodOrURL, url, methodFound := strings.Cut(optMethodAndPath, " ")
 	if methodFound {
 		method = MethodFromBytes([]byte(methodOrURL))
 	} else {
 		url = methodOrURL
 	}
 	v.method = method
-	v.uri = url
+	v.path = url
 	v.handler = handler
 }
+
+// Method is a HTTP request method, parsed by [MethodFromBytes].
+type Method uint8
+
+const (
+	MethUndefined Method = iota // undefined
+	MethGet                     // GET
+	// lol.
+	MethHead // HEAD
+	MethPost // POST
+	MethPut  // PUT
+	// RFC 5789
+	MethPatch   // PATCH
+	MethDelete  // DELETE
+	MethConnect // CONNECT
+	MethOptions // OPTIONS
+	MethTrace   // TRACE
+	MethUnknown // unknown
+)
+
+// MethodFromBytes returns the [Method] matching meth, [MethUndefined] if meth is
+// empty and [MethUnknown] if it names a method this package does not know.
+// Comparison is case sensitive: methods are uppercase, RFC 9110 9.1.
+func MethodFromBytes(meth []byte) (res Method) {
+	if len(meth) == 0 {
+		return MethUndefined
+	}
+	switch unsafe.String(&meth[0], len(meth)) {
+	case "GET":
+		res = MethGet
+	case "HEAD":
+		res = MethHead
+	case "POST":
+		res = MethPost
+	case "PUT":
+		res = MethPut
+	case "PATCH":
+		res = MethPatch
+	case "DELETE":
+		res = MethDelete
+	case "CONNECT":
+		res = MethConnect
+	case "OPTIONS":
+		res = MethOptions
+	case "TRACE":
+		res = MethTrace
+	default:
+		res = MethUnknown
+	}
+	return res
+}
+
+// b2s converts byte slice to a string without memory allocation.
+// See https://groups.google.com/forum/#!msg/Golang-Nuts/ENgbUzYvCuU/90yGx7GUAgAJ .
+func b2s(b []byte) string {
+	return unsafe.String(unsafe.SliceData(b), len(b))
+}

http/httphi/router.go

@@ -0,0 +1,304 @@
+package httphi
+
+import (
+	"errors"
+	"io"
+	"log/slog"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"github.com/soypat/lneto"
+	"github.com/soypat/lneto/internal"
+)
+
+//go:generate stringer -type Method,status -linecomment -output stringers.go
+
+// reconfigureWait bounds how long [Router.Configure] waits for the previous
+// generation to stop serving before reusing its exchange buffers.
+const reconfigureWait = 10 * time.Millisecond
+
+var (
+	errNoRequestProto = errors.New("httphi: request line with no HTTP version")
+	errBusyExchanges  = errors.New("httphi: exchanges still serving, cannot reuse their buffers")
+)
+
+type conn = io.ReadWriteCloser
+
+// Router hosts concurrent safe data.
+type Router struct {
+	mu            sync.Mutex
+	gen           atomic.Uint32
+	numGoro       int
+	reqBuf        int
+	respBuf       int
+	normalizeKeys bool
+	pendingConns  chan job
+	mux           Mux
+
+	globbuf  []byte
+	exchs    []Exchange
+	freeList *Exchange
+
+	backoff lneto.BackoffStrategy
+	log     *slog.Logger
+}
+
+type job struct {
+	exch *Exchange
+}
+
+// RouterConfig configures a [Router]. See [Router.Configure].
+type RouterConfig struct {
+	// FixedNumGoroutines must be set to either -1 (freely allocate new goroutines) or to the number of goroutines
+	// to spawn on [Router.Configure] being called.
+	FixedNumGoroutines int
+	// RequestBufferSize determines the buffer allocated
+	// for processing requests.
+	RequestBufferSize int
+	// ResponseMinBufferSize determines buffer allocated for processing responses.
+	// Response buffer will reuse unused request memory so this is not a strict limit.
+	ResponseMinBufferSize int
+
+	NormalizeOutgoingKeys bool
+	MaxAwaitingConns      int
+
+	Backoff lneto.BackoffStrategy
+	Mux     Mux
+	Logger  *slog.Logger
+}
+
+// Validate returns a non-nil error if the configuration cannot be used to
+// configure a [Router].
+func (cfg RouterConfig) Validate() error {
+	workerMode := cfg.workerMode()
+	if workerMode && cfg.MaxAwaitingConns == 0 ||
+		cfg.Mux == nil ||
+		!workerMode && cfg.FixedNumGoroutines != -1 {
+		return lneto.ErrInvalidConfig
+	} else if cfg.Backoff == nil {
+		return lneto.ErrMissingHALConfig
+	}
+	return nil
+}
+
+func (cfg RouterConfig) workerMode() bool {
+	return cfg.FixedNumGoroutines > 0
+}
+
+// Teardown stops fixed goroutines.
+func (r *Router) TeardownGoroutines() {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	r.teardownGoroutinesLocked()
+}
+
+// teardownGoroutinesLocked closes the job queue fixed goroutines feed from.
+// Requires r.mu held so that a concurrent [Router.Handle] cannot be enqueueing
+// on the channel being closed.
+func (r *Router) teardownGoroutinesLocked() {
+	r.gen.Add(1)
+	if r.pendingConns != nil {
+		close(r.pendingConns)
+		r.pendingConns = nil
+	}
+}
+
+// Configure prepares the router to serve connections, tearing down the previous
+// generation of goroutines and exchanges first. In worker mode it spawns
+// [RouterConfig.FixedNumGoroutines] goroutines and allocates their exchange
+// buffers up front, so the router's memory use does not grow with load.
+//
+// Configure may be called on a serving router, but since the exchange buffers
+// are reused it waits for connections in flight to finish and fails with a
+// non-nil error rather than reconfigure buffers still being served from.
+func (r *Router) Configure(cfg RouterConfig) error {
+	if err := cfg.Validate(); err != nil {
+		return err
+	}
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	r.teardownGoroutinesLocked()
+	gen := r.gen.Load()
+	numgoro := cfg.FixedNumGoroutines
+	workerMode := cfg.workerMode()
+	r.reqBuf = cfg.RequestBufferSize
+	r.respBuf = cfg.ResponseMinBufferSize
+	r.mux = cfg.Mux
+	r.log = cfg.Logger
+	r.normalizeKeys = cfg.NormalizeOutgoingKeys
+	if !workerMode {
+		r.backoff = cfg.Backoff
+		r.numGoro = 0
+		r.pendingConns = nil
+		return nil
+	}
+	if workerMode {
+		jobqueue := make(chan job, cfg.MaxAwaitingConns)
+		if gen > 1 {
+			// Exchange buffers below are reused: the previous generation must be
+			// done serving before they may be handed to the new one.
+			err := r.awaitIdleExchangesLocked(reconfigureWait)
+			if err != nil {
+				return err
+			}
+		}
+		r.freeList = nil // Freelist entries point into the buffers reused below.
+		internal.SliceReuse(&r.exchs, numgoro)
+		r.exchs = r.exchs[:numgoro]
+		rawBuflen := cfg.RequestBufferSize + cfg.ResponseMinBufferSize
+		internal.SliceReuse(&r.globbuf, numgoro*rawBuflen)
+		for i := range numgoro {
+			// TODO exchange buffer alloc
+			goff := i * rawBuflen
+			r.exchs[i].Configure(r.globbuf[goff:goff+rawBuflen], cfg.RequestBufferSize, cfg.NormalizeOutgoingKeys)
+			go r.goroWorker(gen, jobqueue, cfg.Backoff, cfg.Mux)
+		}
+		r.pendingConns = jobqueue
+		r.numGoro = numgoro
+	}
+	return nil
+}
+
+// awaitIdleExchangesLocked waits up to maxWait for exchanges of the previous
+// generation to finish serving so their buffers may be reused. Requires r.mu
+// held; the lock is released while waiting since [Router.freeExch] needs it to
+// free the exchanges being waited on.
+func (r *Router) awaitIdleExchangesLocked(maxWait time.Duration) error {
+	const pollInterval = time.Millisecond
+	for waited := time.Duration(0); ; waited += pollInterval {
+		busy := false
+		for i := range r.exchs {
+			if r.exchs[i].used.Load() {
+				busy = true
+				break
+			}
+		}
+		if !busy {
+			return nil
+		} else if waited >= maxWait {
+			return errBusyExchanges
+		}
+		r.mu.Unlock()
+		time.Sleep(pollInterval)
+		r.mu.Lock()
+	}
+}
+
+// Handle takes ownership of conn and serves one exchange on it, closing it when
+// done. It does not block on the exchange: the connection is handed to a
+// goroutine and Handle returns immediately.
+//
+// Handle returns [lneto.ErrExhausted] when no exchange is free and
+// [lneto.ErrPacketDrop] when the job queue is full. Both leave conn untouched
+// and unclosed for the caller to dispose of: dropping is how a router with
+// fixed memory applies backpressure.
+func (r *Router) Handle(conn conn) error {
+	// Exchange acquisition and the configuration it is served with must be read
+	// under the same lock: [Router.Configure] may run concurrently.
+	r.mu.Lock()
+	exch := r.getExchLocked(conn)
+	numGoro, backoff, mux := r.numGoro, r.backoff, r.mux
+	if exch == nil {
+		r.mu.Unlock()
+		return lneto.ErrExhausted
+	} else if numGoro == 0 {
+		r.mu.Unlock()
+		go r.goroHandle(exch, backoff, mux)
+		return nil
+	}
+	// Enqueue under the lock: [Router.Configure] closes pendingConns while
+	// holding it, so an unlocked send could land on a closed channel. The send
+	// never blocks, so holding the lock cannot stall a worker.
+	var enqueued bool
+	select {
+	case r.pendingConns <- job{exch: exch}:
+		enqueued = true
+	default:
+		// pendingConns cannot store another Conn, we drop and return error.
+		exch.used.Store(false) // release.
+	}
+	r.mu.Unlock()
+	if enqueued {
+		return nil
+	}
+	return lneto.ErrPacketDrop
+}
+
+func (r *Router) goroWorker(gen uint32, queue chan job, backoff lneto.BackoffStrategy, mux Mux) {
+	for job := range queue {
+		exch := job.exch
+		if gen != r.gen.Load() {
+			return
+		} else if exch == nil {
+			panic("httplo: unreachable nil job")
+		}
+		r.goroHandle(exch, backoff, mux)
+	}
+}
+
+func (r *Router) goroHandle(exch *Exchange, backoff lneto.BackoffStrategy, mux Mux) {
+	defer r.freeExch(exch)
+	err := Handle(exch, mux, backoff)
+	if err != nil {
+		if exch.readErr != nil {
+			r.error("goroHandle:ReadFromLimited", slog.String("err", err.Error()))
+		} else {
+			r.error("goroHandle:TryParse?", slog.String("err", err.Error()))
+		}
+	}
+}
+
+func (r *Router) freeExch(exch *Exchange) {
+	const freelistMaxDepth = 5
+	r.mu.Lock()
+	depth := 0
+	for node := r.freeList; node != nil && depth < freelistMaxDepth; node = node.nextFree {
+		depth++
+	}
+	if depth < freelistMaxDepth {
+		// Push at head: appending at the tail would drop every node past the
+		// depth limit instead of dropping the exchange we cannot store.
+		exch.nextFree = r.freeList
+		r.freeList = exch
+	} else {
+		exch.nextFree = nil // Freelist full, exchange is dropped.
+	}
+	exch.Release()
+	r.mu.Unlock()
+}
+
+// getExchLocked returns an exchange acquired on conn. Requires r.mu held.
+func (r *Router) getExchLocked(conn conn) (exch *Exchange) {
+	if r.freeList != nil {
+		// Successor must be read before Acquire: Acquire clears nextFree, so
+		// popping afterwards would truncate the freelist to the popped node.
+		next := r.freeList.nextFree
+		if r.freeList.Acquire(conn) {
+			exch = r.freeList
+			r.freeList = next
+			return exch
+		}
+	}
+	for i := range r.exchs {
+		if r.exchs[i].Acquire(conn) {
+			return &r.exchs[i]
+		}
+	}
+
+	if r.numGoro == 0 {
+		exch := new(Exchange)
+		exch.Configure(make([]byte, r.respBuf+r.reqBuf), r.reqBuf, r.normalizeKeys)
+		exch.Acquire(conn) // Fresh exchange, CAS cannot fail.
+		return exch
+	}
+	return nil
+}
+
+func (r *Router) error(msg string, attrs ...slog.Attr) {
+	internal.LogAttrs(r.log, slog.LevelError, msg, attrs...)
+}
+
+func (r *Router) info(msg string, attrs ...slog.Attr) {
+	internal.LogAttrs(r.log, slog.LevelInfo, msg, attrs...)
+}

http/httphi/router_test.go

@@ -202,7 +202,7 @@ func TestRouterRequestVisibleToHandler(t *testing.T) {
 	var gotMethod, gotURI, gotHost string
 	sm.Handle("GET /index.html", func(ex *Exchange) {
 		gotMethod = string(ex.RequestMethod())
-		gotURI = string(ex.RequestURI())
+		gotURI = string(ex.RequestTarget())
 		gotHost = string(ex.RequestHeader("Host"))
 		ex.WriteHeader(200)
 	})

http/httpraw/cookie.go

@@ -74,6 +74,8 @@ func (c *Cookie) Parse() error {
 	return nil
 }
 
+// ForEach iterates over the cookie's key-value pairs, stopping on the first
+// error returned by cb and returning it.
 func (c *Cookie) ForEach(cb func(key, value []byte) error) error {
 	nc := len(c.kvs)
 	for i := range nc {
@@ -100,6 +102,8 @@ func (c *Cookie) Get(key string) []byte {
 	return nil
 }
 
+// HasKeyOrSingleValue returns true if the cookie contains a pair with the given
+// key or a valueless attribute with the given text, i.e: "Secure" or "HttpOnly".
 func (c *Cookie) HasKeyOrSingleValue(keyOrSingleValue string) bool {
 	nc := len(c.kvs)
 	for i := range nc {

http/httpraw/header.go

@@ -15,6 +15,9 @@ const (
 	strClose         = "close"
 )
 
+// Flags is a bitset of signals gathered while parsing or building a header,
+// such as a status code having been set or the peer requesting connection
+// close. See [Header.Flags].
 type Flags uint16
 
 const (
@@ -27,9 +30,9 @@ const (
 	flagReaderEOF
 	// set if [Header.SetStatus] or [Header.SetStatusInt] has been called.
 	FlagStatusSet
-	FlagReaderError
 )
 
+// HasAny returns true if any of the argument flags are set.
 func (f Flags) HasAny(checkThese Flags) bool {
 	return f&checkThese != 0
 }
@@ -45,9 +48,9 @@ type Header struct {
 	hbuf headerBuf
 
 	// Request fields.
-	method     headerSlice
-	requestURI headerSlice
-	proto      headerSlice
+	method        headerSlice
+	requestTarget headerSlice
+	proto         headerSlice
 
 	// Response fields.
 	statusCode headerSlice
@@ -108,7 +111,7 @@ func (h *Header) TryParse(asResponse bool) (needMoreData bool, err error) {
 	} else if h.flags.HasAny(flagMangledBuffer) {
 		return false, errMangledBuffer
 	}
-	if asResponse && h.statusCode.len == 0 || !asResponse && h.requestURI.start == 0 {
+	if asResponse && h.statusCode.len == 0 || !asResponse && h.requestTarget.start == 0 {
 		err = h.parseFirstLine(asResponse)
 		if err != nil {
 			return err == errNeedMore, err
@@ -351,37 +354,38 @@ func (h *Header) SetMethod(method string) {
 	h.method = h.reuseOrAppend(h.method, method)
 }
 
-// SetRequestURI sets RequestURI for the first HTTP request line.
-func (h *Header) SetRequestURI(requestURI string) {
-	h.requestURI = h.reuseOrAppend(h.requestURI, requestURI)
+// SetRequestTarget sets request-target (URI) for the first HTTP request line.
+func (h *Header) SetRequestTarget(requestTarget string) {
+	h.requestTarget = h.reuseOrAppend(h.requestTarget, requestTarget)
 }
 
-// RequestURI returns RequestURI from the first HTTP request line.
-func (h *Header) RequestURI() []byte {
-	return h.getNonEmptyValue(h.requestURI)
+// RequestTarget returns a view of the request-target (URI) of the first HTTP request line.
+// Called Request-URI in the obsolete RFC 2616, renamed request-target by RFC 9112.
+func (h *Header) RequestTarget() []byte {
+	return h.getNonEmptyValue(h.requestTarget)
 }
 
-// RequestPath returns the request URI up to the query string, i.e: "/search"
-// for "/search?q=go". Returns the whole URI if it contains no query string.
+// RequestPath returns the request-target (URI) up to the query string, i.e: "/search"
+// for "/search?q=go". Returns the whole target if it contains no query string.
 func (h *Header) RequestPath() []byte {
-	uri := h.RequestURI()
-	query := bytes.IndexByte(uri, '?')
+	target := h.RequestTarget()
+	query := bytes.IndexByte(target, '?')
 	if query < 0 {
-		return uri
+		return target
 	}
-	return uri[:query]
+	return target[:query]
 }
 
-// RequestQuery returns the request URI's query string as it appears on the
+// RequestQuery returns the request-target (URI) query string as it appears on the
 // wire, percent-encoded and with '+' undecoded, i.e: "q=go" for "/search?q=go".
-// Returns nil if the URI has no query string. Iterate it with [NextQueryPair].
+// Returns nil if the target has no query string. Iterate it with [NextQueryPair].
 func (h *Header) RequestQuery() []byte {
-	uri := h.RequestURI()
-	start := bytes.IndexByte(uri, '?')
+	target := h.RequestTarget()
+	start := bytes.IndexByte(target, '?')
 	if start < 0 {
 		return nil
 	}
-	return uri[start+1:]
+	return target[start+1:]
 }
 
 // NextQueryPair splits the leading key-value pair off a query string and returns
@@ -461,7 +465,7 @@ func (h *Header) AppendRequest(dst []byte) ([]byte, error) {
 	proto := h.Protocol()
 	if h.flags.HasAny(flagOOMReached) {
 		return dst, errOOM
-	} else if h.requestURI.len == 0 || h.method.len == 0 {
+	} else if h.requestTarget.len == 0 || h.method.len == 0 {
 		return dst, errNeedMethodURI
 	} else if len(proto) == 0 {
 		return dst, errNoProto
@@ -473,7 +477,7 @@ func (h *Header) AppendRequest(dst []byte) ([]byte, error) {
 	} else {
 		dst = append(dst, method...)
 	}
-	uri := h.RequestURI()
+	uri := h.RequestTarget()
 
 	dst = append(dst, ' ')
 	dst = append(dst, uri...)
@@ -531,6 +535,9 @@ func (h *Header) AppendHeaders(dst []byte) []byte {
 	return dst
 }
 
+// String returns the header's wire representation, as a request if it has a
+// request line and as a response otherwise. Returns the error text if neither
+// can be built. Allocates, so it is meant for debugging and logging only.
 func (h *Header) String() string {
 	buf, err := h.AppendRequest(nil)
 	if err != nil {

http/httpraw/header_test.go

@@ -50,8 +50,8 @@ func TestHeaderParseRequest(t *testing.T) {
 	if string(hdr.Method()) != wantMethod {
 		t.Errorf("want method %s, got %q", wantMethod, hdr.Method())
 	}
-	if !bytes.Equal(hdr.RequestURI(), []byte(wantURI)) {
-		t.Errorf("want request URI %q, got %q", wantURI, hdr.RequestURI())
+	if !bytes.Equal(hdr.RequestTarget(), []byte(wantURI)) {
+		t.Errorf("want request URI %q, got %q", wantURI, hdr.RequestTarget())
 	}
 	contentLength, _ := strconv.Atoi(string(hdr.Get("Content-Length")))
 	if contentLength != len(wantMessage) {
@@ -356,7 +356,7 @@ func TestHeaderSetOverwrite(t *testing.T) {
 	var h Header
 	h.Reset(nil)
 	h.SetMethod("GET")
-	h.SetRequestURI("/")
+	h.SetRequestTarget("/")
 	h.SetProtocol("HTTP/1.1")
 
 	h.Set("Host", "first.example.com")
@@ -485,7 +485,7 @@ func TestHeader_AddFullBufferNoPanic(t *testing.T) {
 	h.Reset(buf)
 	h.EnableBufferGrowth(false)
 	h.SetMethod("GET")
-	h.SetRequestURI("/")
+	h.SetRequestTarget("/")
 	h.SetProtocol("HTTP/1.1")
 
 	defer func() {
@@ -531,7 +531,7 @@ func TestHeader_SetIntOverwrite(t *testing.T) {
 	var h Header
 	h.Reset(nil)
 	h.SetMethod("GET")
-	h.SetRequestURI("/")
+	h.SetRequestTarget("/")
 	h.SetProtocol("HTTP/1.1")
 
 	h.SetInt("Content-Length", 100, 10)

http/httpraw/parse.go

@@ -106,7 +106,7 @@ func (h *Header) parseFirstLine(asResponse bool) (err error) {
 	if asResponse {
 		h.statusCode, h.statusText, h.flags, err = h.hbuf.parseFirstLineResponse(h.flags)
 	} else {
-		h.method, h.requestURI, h.proto, h.flags, err = h.hbuf.parseFirstLineRequest(h.flags)
+		h.method, h.requestTarget, h.proto, h.flags, err = h.hbuf.parseFirstLineRequest(h.flags)
 	}
 	return err
 }

http/httpraw/parse_test.go

@@ -52,8 +52,8 @@ func TestTryParse_IncrementalRequest(t *testing.T) {
 	if string(hdr.Method()) != "GET" {
 		t.Errorf("method = %q; want GET", hdr.Method())
 	}
-	if string(hdr.RequestURI()) != "/index.html" {
-		t.Errorf("URI = %q; want /index.html", hdr.RequestURI())
+	if string(hdr.RequestTarget()) != "/index.html" {
+		t.Errorf("URI = %q; want /index.html", hdr.RequestTarget())
 	}
 
 	// Verify headers via ForEach.
@@ -432,7 +432,7 @@ func TestHeader_RequestRoundTrip(t *testing.T) {
 	hdr.Reset(make([]byte, 0, 256))
 	hdr.SetProtocol("HTTP/1.1")
 	hdr.SetMethod("POST")
-	hdr.SetRequestURI("/api/data")
+	hdr.SetRequestTarget("/api/data")
 	hdr.Add("Host", "example.com")
 	hdr.Add("Content-Type", "application/json")
 
@@ -454,8 +454,8 @@ func TestHeader_RequestRoundTrip(t *testing.T) {
 	if string(hdr2.Method()) != "POST" {
 		t.Errorf("re-parsed method = %q; want POST", hdr2.Method())
 	}
-	if string(hdr2.RequestURI()) != "/api/data" {
-		t.Errorf("re-parsed URI = %q; want /api/data", hdr2.RequestURI())
+	if string(hdr2.RequestTarget()) != "/api/data" {
+		t.Errorf("re-parsed URI = %q; want /api/data", hdr2.RequestTarget())
 	}
 	if string(hdr2.Get("Host")) != "example.com" {
 		t.Errorf("re-parsed Host = %q; want example.com", hdr2.Get("Host"))
@@ -504,8 +504,8 @@ func TestParseRequest_NoProtocol(t *testing.T) {
 	if string(hdr.Method()) != "GET" {
 		t.Errorf("method = %q; want GET", hdr.Method())
 	}
-	if string(hdr.RequestURI()) != "/simple" {
-		t.Errorf("URI = %q; want /simple", hdr.RequestURI())
+	if string(hdr.RequestTarget()) != "/simple" {
+		t.Errorf("URI = %q; want /simple", hdr.RequestTarget())
 	}
 	if hdr.Protocol() != nil {
 		t.Errorf("protocol should be nil for version-less request, got %q", hdr.Protocol())

x/xnet/xnet_fuzz_test.go

@@ -32,7 +32,7 @@ func FuzzStackPacketHTTP(f *testing.F) {
 	}
 	hdr.SetMethod("GET")
 	hdr.SetProtocol("HTTP/1.1")
-	hdr.SetRequestURI("/")
+	hdr.SetRequestTarget("/")
 	data := hdr.AppendHeaders(nil)
 
 	pktnum := 0