mid refactor of KVBuffer into Header

http/httphi/exchange.go

@@ -434,7 +434,7 @@ func (exch *Exchange) RequestParseForm(dst *httpraw.Form, buf []byte) error {
 
 	length, present, err := exch.RequestContentLength()
 	if !present {
-		dst.Reset(nil)
+		dst.Reset(nil, 0)
 		return nil // No length is no body, RFC 9112 6.3.
 	} else if err != nil {
 		return err
@@ -454,7 +454,7 @@ func (exch *Exchange) RequestParseForm(dst *httpraw.Form, buf []byte) error {
 			return err
 		}
 	}
-	dst.Reset(buf)
+	dst.Reset(buf, 0)
 	return dst.Parse()
 }
 

http/httpraw/cookie.go

@@ -77,8 +77,17 @@ func (c *Cookie) Get(key string) []byte { return c.kv.Get(key) }
 
 // 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".
+// It cannot defer to [KVBuffer.Present]: parseCookie stores a valueless
+// attribute with an empty key and the text as the value, so a key-only lookup
+// would never match one.
 func (c *Cookie) HasKeyOrSingleValue(keyOrSingleValue string) bool {
-	return c.kv.Present(keyOrSingleValue)
+	for i, nc := 0, c.kv.Len(); i < nc; i++ {
+		k, v := c.kv.At(i)
+		if (len(k) == 0 && b2s(v) == keyOrSingleValue) || b2s(k) == keyOrSingleValue {
+			return true
+		}
+	}
+	return false
 }
 
 // parseCookie parses a cookie inside cookie buffer and adds it to cookie buffer..

http/httpraw/form.go

@@ -8,39 +8,35 @@ package httpraw
 // undecoded, until [Form.Decode] rewrites them in place. The caller bounds the
 // data: Form parses the buffer it is handed and reads nothing more.
 type Form struct {
-	buf []byte
-	kvs []argsKV
+	kv KVBuffer
 }
 
+func (f *Form) EnableBufferGrowth(enableGrowth bool) { f.kv.EnableBufferGrowth(enableGrowth) }
+
 // Reset discards parsed pairs and sets the buffer to parse in place.
 // If buf is nil the current buffer is reused.
-func (f *Form) Reset(buf []byte) {
-	if buf == nil {
-		buf = f.buf[:0]
-	}
-	*f = Form{
-		buf: buf,
-		kvs: f.kvs[:0],
-	}
+func (f *Form) Reset(buf []byte, capKV int) {
+	f.kv.Reset(buf, capKV)
 }
 
 // ParseBytes copies the argument bytes to the Form's underlying buffer and parses them.
 func (f *Form) ParseBytes(b []byte) error {
-	f.Reset(nil)
-	f.buf = append(f.buf[:0], b...)
+	f.Reset(nil, 0)
+	err := f.kv.ReadFromBytes(b)
+	if err != nil {
+		return err
+	}
 	return f.Parse()
 }
 
 // Parse parses the form's buffer in place.
 func (f *Form) Parse() error {
-	f.kvs = f.kvs[:0]
-	key, value, rest := NextQueryPair(f.buf)
+	f.kv.discardKVs()
+	key, value, rest := NextQueryPair(f.kv.buf)
 	for key != nil {
-		kv := argsKV{key: bytes2tok(f.buf, key)}
-		if value != nil {
-			kv.value = bytes2tok(f.buf, value)
+		if !f.kv.setInternal(key, value) {
+			return errOOM
 		}
-		f.kvs = append(f.kvs, kv)
 		key, value, rest = NextQueryPair(rest)
 	}
 	return nil
@@ -50,66 +46,51 @@ func (f *Form) Parse() error {
 // '+' with the bytes they encode. Decoding only shrinks, so no memory is added.
 func (f *Form) Decode() error {
 	const plusAsSpace = true // Form encoded data, unlike a path.
-	for i := range f.kvs {
-		kv := &f.kvs[i]
-		n, err := CopyDecodedPercentURL(tok2bytes(f.buf, kv.key), tok2bytes(f.buf, kv.key), plusAsSpace)
+	nkvs := f.kv.Len()
+	for i := range nkvs {
+		k, v := f.kv.At(i)
+		nk, err := CopyDecodedPercentURL(k, k, plusAsSpace)
 		if err != nil {
 			return err
-		}
-		kv.key.len = tokint(n)
-		if !kv.HasValue() {
+		} else if len(v) == 0 {
+			if nk != len(k) {
+				f.kv.setAt(i, k, v)
+			}
 			continue
 		}
-		n, err = CopyDecodedPercentURL(tok2bytes(f.buf, kv.value), tok2bytes(f.buf, kv.value), plusAsSpace)
+		nv, err := CopyDecodedPercentURL(v, v, plusAsSpace)
 		if err != nil {
 			return err
 		}
-		kv.value.len = tokint(n)
+		if nk != len(k) || nv != len(v) {
+			f.kv.setAt(i, k[:nk], v[:nv])
+		}
 	}
 	return nil
 }
 
 // Len returns the amount of key-value pairs parsed.
-func (f *Form) Len() int { return len(f.kvs) }
+func (f *Form) Len() int { return f.kv.Len() }
 
 // Pair returns the i'th key-value pair in wire order. The value is nil for a
 // pair with no '=', i.e: "ok" in "ok&q=go", which distinguishes it from "ok="
 // where the value is present and empty.
 func (f *Form) Pair(i int) (key, value []byte) {
-	kv := f.kvs[i]
-	key = tok2bytes(f.buf, kv.key)
-	if kv.HasValue() {
-		value = tok2bytes(f.buf, kv.value)
-	}
-	return key, value
+	return f.kv.At(i)
 }
 
 // Get returns the value of the first pair matching key, nil if absent or if the
 // pair has no value. Bytes are compared as stored, so call [Form.Decode] first
 // when keys may be encoded.
-func (f *Form) Get(key string) []byte {
-	for i := range f.kvs {
-		gotKey, value := f.Pair(i)
-		if b2s(gotKey) == key {
-			return value
-		}
-	}
-	return nil
-}
+func (f *Form) Get(key string) []byte { return f.kv.Get(key) }
 
 // Has returns true if key is present, with or without a value.
-func (f *Form) Has(key string) bool {
-	for i := range f.kvs {
-		if b2s(tok2bytes(f.buf, f.kvs[i].key)) == key {
-			return true
-		}
-	}
-	return false
-}
+func (f *Form) Has(key string) bool { return f.kv.Present(key) }
 
 // AppendKeyValues appends the form's wire representation to dst and returns it.
 func (f *Form) AppendKeyValues(dst []byte) []byte {
-	for i := range f.kvs {
+	nkv := f.kv.Len()
+	for i := range nkv {
 		key, value := f.Pair(i)
 		if i > 0 {
 			dst = append(dst, '&')

http/httpraw/form_test.go

@@ -125,7 +125,7 @@ func TestFormParseReuseNoAlloc(t *testing.T) {
 		t.Fatal(err)
 	}
 	allocs := testing.AllocsPerRun(100, func() {
-		f.Reset(body)
+		f.Reset(body, 0)
 		f.Parse()
 	})
 	if allocs != 0 {

http/httpraw/header.go

@@ -3,7 +3,6 @@ package httpraw
 import (
 	"bytes"
 	"io"
-	"slices"
 	"strconv"
 )
 
@@ -29,6 +28,7 @@ const (
 	flagConnClose
 	flagNoHTTP11
 	flagMangledBuffer // set when header fields appended to buffer via Add,Set calls
+	flagKVAppended    // set after KV appended to buffer outside Read methods.
 	flagReaderEOF
 	// set if [Header.SetStatus] or [Header.SetStatusInt] has been called.
 	FlagStatusSet
@@ -57,30 +57,27 @@ type Header struct {
 	// Response fields.
 	statusCode headerSlice
 	statusText headerSlice
-
-	flags Flags
-	_     noCopy
+	_          noCopy
 }
 
 // Flags returns [Flags] to signal status code has been set, Connection:Close or other useful signals provided by flags.
-func (h *Header) Flags() Flags { return h.flags }
+func (h *Header) Flags() Flags { return h.hbuf.kv.flags }
 
 // ConfigBufferGrowth configures the memory the header may use. Setting
 // outlives [Header.Reset]. Call before parsing/reading.
 //
 // enableBufferGrowth enables growing both the header buffer and the header key/value pair slice.
 func (h *Header) ConfigBufferGrowth(enableBufferGrowth bool) {
-	if !enableBufferGrowth {
-		h.flags |= flagNoBufferGrow
-	} else {
-		h.flags &^= flagNoBufferGrow
-	}
+	h.hbuf.kv.EnableBufferGrowth(enableBufferGrowth)
 }
 
 // ParseBytes copies the bytes into buffer and parses the HTTP header. It fails if HTTP header data is incomplete.
 func (h *Header) ParseBytes(asResponse bool, b []byte) error {
 	h.Reset(nil, 0)
-	h.hbuf.readFromBytes(b)
+	err := h.hbuf.kv.ReadFromBytes(b)
+	if err != nil {
+		return err
+	}
 	return h.parse(asResponse)
 }
 
@@ -88,7 +85,7 @@ func (h *Header) ParseBytes(asResponse bool, b []byte) error {
 // It fails if HTTP data is incomplete.
 func (h *Header) Parse(asResponse bool) error {
 	debuglog("http:parse:reset")
-	h.Reset(h.hbuf.buf, 0)
+	h.Reset(h.hbuf.kv.buf, 0)
 	debuglog("http:parse:start")
 	return h.parse(asResponse)
 }
@@ -110,9 +107,10 @@ func (h *Header) Parse(asResponse bool) error {
 //		return err
 //	}
 func (h *Header) TryParse(asResponse bool) (needMoreData bool, err error) {
-	if h.flags.HasAny(flagDoneParsingHeader) {
+	flags := h.Flags()
+	if flags.HasAny(flagDoneParsingHeader) {
 		return false, errAlreadyParsed
-	} else if h.flags.HasAny(flagMangledBuffer) {
+	} else if flags.HasAny(flagMangledBuffer) {
 		return false, errMangledBuffer
 	}
 	if asResponse && h.statusCode.len == 0 || !asResponse && h.requestTarget.start == 0 {
@@ -121,80 +119,42 @@ func (h *Header) TryParse(asResponse bool) (needMoreData bool, err error) {
 			return err == ErrNeedMoreData, err
 		}
 	}
-	err = h.parseNextHeaders(h.flags)
+	err = h.parseNextHeaders(flags)
 	return err == ErrNeedMoreData, err
 }
 
 // ParsingSuccess returns true if TryParse was successful, that is to say it returned needMoreData==false and err==nil.
 func (h *Header) ParsingSuccess() bool {
-	return h.flags.HasAny(flagDoneParsingHeader)
+	return h.Flags().HasAny(flagDoneParsingHeader)
 }
 
 // ReadFromLimited reads at most maxBytesToRead from reader and appends them to underlying buffer.
 // Used to accumulate HTTP header for later parsing with [Header.TryParse].
 // If read is successful (read length>0) and reader returns [io.EOF] then ReadFromLimited will return a nil error.
 func (h *Header) ReadFromLimited(r io.Reader, maxBytesToRead int) (int, error) {
-	if maxBytesToRead <= 0 {
-		return 0, ErrSmallHeaderBuffer
-	} else if h.flags.HasAny(flagMangledBuffer) {
-		return 0, errMangledBuffer
-	} else if h.flags.HasAny(flagReaderEOF) {
-		return 0, io.EOF // Now we do return EOF.
-	}
-	free := h.BufferFree()
-	if free < maxBytesToRead {
-		if h.flags.HasAny(flagNoBufferGrow) {
-			return 0, ErrSmallHeaderBuffer
-		}
-		h.hbuf.buf = slices.Grow(h.hbuf.buf, maxBytesToRead)
-	}
-	blen := len(h.hbuf.buf)
-	b := h.hbuf.buf[blen:min(blen+maxBytesToRead, cap(h.hbuf.buf))]
-	if len(b) == 0 {
-		return 0, ErrSmallHeaderBuffer
-	}
-	n, err := r.Read(b)
-	if err != nil && err == io.EOF {
-		h.flags |= flagReaderEOF
-		if n > 0 {
-			err = nil // Nil-out error if read was succesful so as to not spook readers.
-		}
-	}
-	h.hbuf.buf = h.hbuf.buf[:blen+n]
-	return n, err
+	return h.hbuf.kv.ReadLimited(r, maxBytesToRead)
 }
 
 // ReadFromBytes appends argument buffer to underlying buffer.
 // Used to accumulate HTTP header for later parsing with [Header.TryParse].
-func (h *Header) ReadFromBytes(b []byte) (int, error) {
-	if len(b) == 0 {
-		return 0, ErrSmallHeaderBuffer
-	}
-	free := h.BufferFree()
-	if free < len(b) {
-		if h.flags.HasAny(flagNoBufferGrow) {
-			return 0, ErrSmallHeaderBuffer
-		}
-		h.hbuf.buf = slices.Grow(h.hbuf.buf, len(b))
-	}
-	h.hbuf.readFromBytes(b)
-	return len(b), nil
+func (h *Header) ReadFromBytes(b []byte) error {
+	return h.hbuf.kv.ReadFromBytes(b)
 }
 
 // BufferReceived returns the amoung of bytes read during calls to Read* methods.
 // Returns 0 if buffer is invalid/mangled.
 func (h *Header) BufferReceived() int {
-	if h.flags.HasAny(flagMangledBuffer | flagOOMReached) {
+	if h.Flags().HasAny(flagMangledBuffer | flagOOMReached) {
 		return 0
 	}
-	return len(h.hbuf.buf)
+	return len(h.hbuf.kv.BufferRaw())
 }
 
 // BufferParsed returns the amount of bytes parsed during a call to Parse* methods.
 // If the Parse* method completed without error then BufferParsed returns the header's length including the final "\r\n\r\n" text.
 // BufferParsed returns 0 if the buffer is invalid/mangled or if no header data has been parsed succesfully.
 func (h *Header) BufferParsed() int {
-	if h.flags.HasAny(flagMangledBuffer | flagOOMReached) {
+	if h.Flags().HasAny(flagMangledBuffer | flagOOMReached) {
 		return 0
 	}
 	return h.hbuf.off
@@ -202,13 +162,13 @@ func (h *Header) BufferParsed() int {
 
 // BufferRaw returns the undeerlying buffer as stored currently in memory.
 // The length of the returned buffer is the used portion. Capacity of returned slice is [Header.BufferCapacity].
-func (h *Header) BufferRaw() []byte { return h.hbuf.buf }
+func (h *Header) BufferRaw() []byte { return h.hbuf.kv.BufferRaw() }
 
 // BufferUsed returns the raw memory used.
 //
 //	BufferUsed + BufferFree == BufferCapacity
 func (h *Header) BufferUsed() int {
-	return len(h.hbuf.buf)
+	return len(h.hbuf.kv.BufferRaw())
 }
 
 // BufferFree returns amount of bytes free in underlying buffer.
@@ -222,29 +182,12 @@ func (h *Header) BufferFree() int {
 //
 //	BufferUsed + BufferFree == BufferCapacity
 func (h *Header) BufferCapacity() int {
-	return cap(h.hbuf.buf)
+	return cap(h.hbuf.kv.BufferRaw())
 }
 
 // ForEach iterates over header key-value field tuples.
-func (h *Header) ForEach(cb func(key, value []byte) error) error {
-	return h.hbuf.forEach(cb)
-}
-
-func (hb *headerBuf) forEach(cb func(key, value []byte) error) error {
-	nh := len(hb.headers)
-	for i := range nh {
-		kv := hb.headers[i]
-		if !kv.isValid() {
-			continue
-		}
-		key := hb.musttoken(kv.key)
-		value := hb.musttoken(kv.value)
-		err := cb(key, value)
-		if err != nil {
-			return err
-		}
-	}
-	return nil
+func (h *Header) ForEach(cb func(key, value []byte) bool) {
+	h.hbuf.kv.ForEach(cb)
 }
 
 // Reset discards all parsed data and sets the buffer data to buf. This method
@@ -259,23 +202,21 @@ func (h *Header) Reset(buf []byte, numHeaderCapacity int) {
 	const persistentFlags = flagNoBufferGrow
 	debuglog("http:reset:hbuf")
 	h.hbuf.reset(buf, numHeaderCapacity)
-	if h.flags.HasAny(flagNoBufferGrow) && cap(h.hbuf.buf) < 32 {
+	if h.Flags().HasAny(flagNoBufferGrow) && h.BufferCapacity() < 32 {
 		panic("small buffer and flagNoBufferGrow set")
 	}
-	*h = Header{
-		hbuf:  h.hbuf,
-		flags: h.flags & persistentFlags,
-	}
+	*h = Header{hbuf: h.hbuf}
 	debuglog("http:reset:done")
 }
 
 // Body returns the surplus data following headers. It is only valid as long as Parse* or Reset methods are not called.
 func (h *Header) Body() ([]byte, error) {
 	debuglog("http:body")
-	if h.flags.HasAny(flagMangledBuffer) {
+	flags := h.Flags()
+	if flags.HasAny(flagMangledBuffer) {
 		return nil, errMangledBuffer
-	} else if h.flags.HasAny(flagDoneParsingHeader) {
-		return h.hbuf.buf[h.hbuf.off:], nil
+	} else if flags.HasAny(flagDoneParsingHeader) {
+		return h.BufferRaw()[h.hbuf.off:], nil
 	}
 	return nil, errUnparsed
 }
@@ -303,48 +244,51 @@ func (h *Header) SetInt(key string, value int64, base int) {
 
 // Set sets a key-value pair in the HTTP header.
 // Calling Set mangles the buffer.
-func (h *Header) Set(key, value string) {
-	useKv := h.takeReusableSlot(key)
-	if useKv == nil {
-		h.appendHeader(key, value)
-	} else {
-		useKv.value = h.reuseOrAppend(useKv.value, value)
-	}
+func (h *Header) Set(key, value string) (enoughSpace bool) {
+	return h.hbuf.kv.Set(key, value)
+
+	// useKv := h.takeReusableSlot(key)
+	// if useKv == nil {
+	// 	h.appendHeader(key, value)
+	// } else {
+	// 	useKv.value = h.reuseOrAppend(useKv.value, value)
+	// }
 }
 
 // takeReusableSlot returns the valid key-value entry for key with the largest
 // value buffer (best candidate for in-place reuse) and invalidates any other
 // entries sharing the key. Returns nil if the key is not present.
 func (h *Header) takeReusableSlot(key string) *argsKV {
-	hb := &h.hbuf
+	// hb := &h.hbuf
 	var useKv *argsKV
-	for i := 0; i < len(hb.headers); i++ {
-		// Search for key-value with largest buffer for value to store value reusing buffer.
-		gotkv := &hb.headers[i]
-		if gotkv.isValid() && b2s(hb.musttoken(gotkv.key)) == key {
-			if useKv == nil {
-				useKv = gotkv
-			} else if gotkv.value.len > useKv.value.len {
-				useKv.invalidate()
-				useKv = gotkv
-			} else {
-				gotkv.invalidate()
-			}
-		}
-	}
+	// for i := 0; i < len(hb.headers); i++ {
+	// 	// Search for key-value with largest buffer for value to store value reusing buffer.
+	// 	gotkv := &hb.headers[i]
+	// 	if gotkv.isValidHeader() && b2s(hb.musttoken(gotkv.key)) == key {
+	// 		if useKv == nil {
+	// 			useKv = gotkv
+	// 		} else if gotkv.value.len > useKv.value.len {
+	// 			useKv.invalidate()
+	// 			useKv = gotkv
+	// 		} else {
+	// 			gotkv.invalidate()
+	// 		}
+	// 	}
+	// }
 	return useKv
 }
 
 // Get gets the first exact-match value of a key found in the headers. Use [Header.ForEach] to find multiple values corresponding to same key.
 func (h *Header) Get(key string) []byte {
-	debuglog("http:get:start")
-	kv := h.peekHeader(key)
-	if kv.isValid() {
-		debuglog("http:get:found")
-		return h.hbuf.musttoken(kv.value)
-	}
-	debuglog("http:get:notfound")
-	return nil
+	return h.hbuf.kv.Get(key)
+	// debuglog("http:get:start")
+	// kv := h.peekHeader(key)
+	// if kv.isValidHeader() {
+	// 	debuglog("http:get:found")
+	// 	return h.hbuf.musttoken(kv.value)
+	// }
+	// debuglog("http:get:notfound")
+	// return nil
 }
 
 // GetFold gets the first value whose key matches key under ASCII case-insensitive
@@ -352,11 +296,10 @@ func (h *Header) Get(key string) []byte {
 // Use [Header.Get] for exact match and [Header.ForEach] to find multiple values
 // corresponding to same key.
 func (h *Header) GetFold(key string) []byte {
-	hb := &h.hbuf
-	for i := 0; i < len(hb.headers); i++ {
-		kv := hb.headers[i]
-		if kv.isValid() && asciiEqualFold(b2s(hb.musttoken(kv.key)), key) {
-			return hb.musttoken(kv.value)
+	nh := h.hbuf.kv.Len()
+	for i := range nh {
+		if asciiEqualFold(key, b2s(h.hbuf.kv.AtKey(i))) {
+			return h.hbuf.kv.AtValue(i)
 		}
 	}
 	return nil
@@ -387,9 +330,9 @@ func asciiEqualFold(a, b string) bool {
 
 // NormalizeKeys normalizes all header keys. i.e: CONTENT-type -> Content-Type
 func (h *Header) NormalizeKeys() {
-	for _, kv := range h.hbuf.headers {
-		if kv.isValid() {
-			NormalizeHeaderKey(h.hbuf.musttoken(kv.key))
+	for i, kv := range h.hbuf.kv.kvs {
+		if kv.isValidHeader() {
+			NormalizeHeaderKey(h.hbuf.kv.AtKey(i))
 		}
 	}
 }
@@ -507,19 +450,19 @@ func (h *Header) Status() (code, statusText []byte) {
 	if h.statusCode.len == 0 {
 		return nil, nil
 	}
-	return h.hbuf.musttoken(h.statusCode), h.hbuf.musttoken(h.statusText)
+	return h.hbuf.kv.musttoken(h.statusCode), h.hbuf.kv.musttoken(h.statusText)
 }
 
 // SetStatus sets the response header's status code and status text. i.e: "200" "OK".
 func (h *Header) SetStatus(code, statusText string) {
-	h.flags |= FlagStatusSet
+	h.hbuf.kv.flags |= FlagStatusSet
 	h.statusCode = h.reuseOrAppend(h.statusCode, code)
 	h.statusText = h.reuseOrAppend(h.statusText, statusText)
 }
 
 // SetStatusInt is identical to [Header.SetStatus] but performs integer to text conversion for status code.
 func (h *Header) SetStatusInt(code int64, statusText string) {
-	h.flags |= FlagStatusSet
+	h.hbuf.kv.flags |= FlagStatusSet
 	h.statusCode = h.reuseOrAppendInt(h.statusCode, code, 10)
 	h.statusText = h.reuseOrAppend(h.statusText, statusText)
 }
@@ -528,13 +471,13 @@ func (h *Header) getNonEmptyValue(s headerSlice) []byte {
 	if s.len == 0 {
 		return nil // If empty then value is invalid, return nil.
 	}
-	return h.hbuf.musttoken(s)
+	return h.hbuf.kv.musttoken(s)
 }
 
 // AppendRequest appends the request header representation to the buffer and returns the result.
 func (h *Header) AppendRequest(dst []byte) ([]byte, error) {
 	proto := h.Protocol()
-	if h.flags.HasAny(flagOOMReached) {
+	if h.hbuf.kv.flags.HasAny(flagOOMReached) {
 		return dst, errOOM
 	} else if h.requestTarget.len == 0 || h.method.len == 0 {
 		return dst, errNeedMethodURI
@@ -574,7 +517,7 @@ func (h *Header) AppendResponse(dst []byte) ([]byte, error) {
 // AppendResponseNoHeaders appends the first line of the response containing protocol and status code/text: i.e: "HTTP/1.1 200 OK\r\n"
 func (h *Header) AppendResponseNoHeaders(dst []byte) ([]byte, error) {
 	proto := h.Protocol()
-	if h.flags.HasAny(flagOOMReached) {
+	if h.hbuf.kv.flags.HasAny(flagOOMReached) {
 		return dst, errOOM
 	} else if h.statusCode.len == 0 || h.statusText.len == 0 {
 		return dst, errBadStatusCodeTxt
@@ -595,12 +538,10 @@ func (h *Header) AppendResponseNoHeaders(dst []byte) ([]byte, error) {
 // AppendHeaders appends headers to buffer. Use AppendRequest and AppendResponse over this.
 // Does not append extra \r\n to end. Appends nothing if contains no headers.
 func (h *Header) AppendHeaders(dst []byte) []byte {
-	for i, n := 0, len(h.hbuf.headers); i < n; i++ {
-		kv := &h.hbuf.headers[i]
-		if kv.isValid() {
-			key := h.hbuf.musttoken(kv.key)
-			value := h.hbuf.musttoken(kv.value)
-			dst = appendHeaderLine(dst, b2s(key), b2s(value))
+	for i, kv := range h.hbuf.kv.kvs {
+		if kv.isValidHeader() {
+			k, v := h.hbuf.kv.At(i)
+			dst = appendHeaderLine(dst, b2s(k), b2s(v))
 		}
 	}
 	return dst

http/httpraw/kvbuffer.go

@@ -1,7 +1,9 @@
 package httpraw
 
 import (
+	"io"
 	"slices"
+	"strconv"
 
 	"github.com/soypat/lneto/internal"
 )
@@ -26,6 +28,52 @@ func (mb *KVBuffer) EnableBufferGrowth(enableGrowth bool) {
 	}
 }
 
+func (mb *KVBuffer) discardKVs() { mb.kvs = mb.kvs[:0] }
+
+func (mb *KVBuffer) BufferGrowthEnabled() bool { return !mb.flags.HasAny(flagNoBufferGrow) }
+
+func (mb *KVBuffer) ReadFromBytes(buf []byte) error {
+	if mb.flags.HasAny(flagMangledBuffer) {
+		return errMangledBuffer
+	} else if len(buf)+cap(mb.buf) > maxBufLen {
+		return errOOM
+	}
+	free := mb.free()
+	if len(buf) > free && !mb.BufferGrowthEnabled() {
+		return errOOM
+	}
+	mb.buf = append(mb.buf, buf...)
+	return nil
+}
+
+func (mb *KVBuffer) ReadLimited(r io.Reader, limit int) (int, error) {
+	if mb.flags.HasAny(flagMangledBuffer) {
+		return 0, errMangledBuffer
+	} else if mb.flags.HasAny(flagReaderEOF) {
+		return 0, io.EOF
+	} else if limit <= 0 {
+		return 0, io.ErrNoProgress
+	} else if len(mb.buf) >= maxBufLen {
+		return 0, errOOM
+	}
+	free := mb.free()
+	if limit > free {
+		if !mb.BufferGrowthEnabled() {
+			return 0, errOOM
+		}
+		mb.buf = slices.Grow(mb.buf, limit)
+	}
+	n, err := r.Read(mb.buf[len(mb.buf):min(len(mb.buf)+limit, maxBufLen)])
+	mb.buf = mb.buf[:len(mb.buf)+n]
+	if err != nil {
+		if n > 0 && err == io.EOF {
+			mb.flags |= flagReaderEOF
+			err = nil // Nil out EOF to not scare off readers.
+		}
+	}
+	return n, err
+}
+
 func (mb *KVBuffer) Reset(buf []byte, kvCap int) {
 	if buf == nil {
 		mb.buf = mb.buf[:0]
@@ -41,15 +89,19 @@ func (mb *KVBuffer) CopyFrom(src *KVBuffer) {
 	mb.kvs = append(mb.kvs[:0], src.kvs...)
 }
 
+// Get returns the value of the first pair matching key.
+// Bytes are compared as stored, so if using a Form call [Form.Decode] first when keys may be encoded.
+// Returns nil for an absent key and for a valueless pair alike, so use
+// [KVBuffer.Present] to tell the two apart.
 func (mb *KVBuffer) Get(key string) []byte {
-	v := mb.getIdx(key)
-	if v < 0 {
+	i := mb.getIdx(key)
+	if i < 0 {
 		return nil
 	}
-	return mb.musttoken(mb.kvs[v].value)
+	return mb.AtValue(i)
 }
 
-// ForEach iterates over the cookie's key-value pairs until cb returns false.
+// ForEach iterates over the cookie's key-value pairs as stored until cb returns false.
 func (c *KVBuffer) ForEach(cb func(key, value []byte) bool) {
 	nc := len(c.kvs)
 	for i := range nc {
@@ -61,18 +113,76 @@ func (c *KVBuffer) ForEach(cb func(key, value []byte) bool) {
 	}
 }
 
-func (mb *KVBuffer) Present(key string) bool {
+// Has returns true if key is present, with or without a value.
+func (mb *KVBuffer) Present(key string) bool { // TODO: rename to Has.
 	return mb.getIdx(key) >= 0
 }
-func (mb *KVBuffer) Add(key, value string) bool {
+
+// Has returns true if key is present, with or without a value.
+func (mb *KVBuffer) HasKeyValue(key, value string) bool {
+	idx := mb.getIdx(key)
+	if idx >= 0 {
+		return b2s(mb.musttoken(mb.kvs[idx].value)) == value
+	}
+	return false
+}
+func (mb *KVBuffer) Add(key, value string) (enoughSpace bool) {
 	mb.appendPair(key, value)
 	return mb.getIdx(key) >= 0
 }
 
-func (mb *KVBuffer) setInternal(key, value []byte) bool {
+// Set replaces key's value and invalidates every other pair sharing the key, so
+// a following [KVBuffer.Get] sees exactly one value.
+//
+// It rewrites in place when it can: of the pairs it would invalidate it keeps
+// the smallest whose key and value regions both still hold the new pair,
+// leaving the roomier regions for a later Set. When none fits the pair is
+// appended with [KVBuffer.Add] and the invalidated regions are stranded, since
+// nothing here compacts the buffer.
+func (mb *KVBuffer) Set(key, value string) (enoughSpace bool) {
+	reuse := -1
+	for i := range mb.kvs {
+		kv := &mb.kvs[i]
+		if !kv.isValid() || b2s(mb.musttoken(kv.key)) != key {
+			continue
+		}
+		// A valueless pair holds no value region, so reusing one would write the
+		// value over byte 0. Let it fall through to Add, which gives the pair a
+		// real region and keeps "ok" distinct from "ok=".
+		fits := kv.HasValue() && int(kv.key.len) >= len(key) && int(kv.value.len) >= len(value)
+		if fits && (reuse < 0 || kv.size() < mb.kvs[reuse].size()) {
+			if reuse >= 0 {
+				mb.kvs[reuse].invalidate() // Superseded by a tighter fit.
+			}
+			reuse = i
+			continue
+		}
+		kv.invalidate()
+	}
+	if reuse < 0 {
+		return mb.Add(key, value)
+	}
+	mb.overwriteAt(reuse, key, value)
+	return true
+}
+
+// overwriteAt writes key and value over the regions pair i already owns. The
+// caller must have checked both fit; the bytes freed by a shorter pair are
+// stranded, not reclaimed.
+func (mb *KVBuffer) overwriteAt(i int, key, value string) {
+	mb.flags |= flagMangledBuffer
+	kv := &mb.kvs[i]
+	copy(mb.buf[kv.key.start:], key)
+	kv.key.len = tokint(len(key))
+	copy(mb.buf[kv.value.start:], value)
+	kv.value.len = tokint(len(value))
+}
+
+func (mb *KVBuffer) setInternal(key, value []byte) (enoughSpace bool) {
 	if !mb.canAddOneKV() {
 		return false
 	}
+	mb.flags |= flagKVAppended
 	mb.kvs = append(mb.kvs, argsKV{
 		key:   mb.slice(key),
 		value: mb.slice(value),
@@ -83,10 +193,26 @@ func (mb *KVBuffer) setInternal(key, value []byte) bool {
 func (mb *KVBuffer) Len() int { return len(mb.kvs) }
 func (mb *KVBuffer) At(i int) (key, value []byte) {
 	kv := mb.kvs[i]
+	if !kv.HasValue() {
+		return mb.musttoken(kv.key), nil
+	}
 	return mb.musttoken(kv.key), mb.musttoken(kv.value)
 }
-func (mb *KVBuffer) AtKey(i int) (key []byte)   { return mb.musttoken(mb.kvs[i].key) }
-func (mb *KVBuffer) AtValue(i int) (key []byte) { return mb.musttoken(mb.kvs[i].value) }
+func (mb *KVBuffer) setAt(i int, k, v []byte) {
+	mb.flags |= flagMangledBuffer
+	mb.kvs[i] = argsKV{
+		key:   bytes2tok(mb.buf, k),
+		value: bytes2tok(mb.buf, v),
+	}
+}
+
+func (mb *KVBuffer) AtKey(i int) (key []byte) { return mb.musttoken(mb.kvs[i].key) }
+func (mb *KVBuffer) AtValue(i int) (key []byte) {
+	if !mb.kvs[i].HasValue() {
+		return nil
+	}
+	return mb.musttoken(mb.kvs[i].value)
+}
 
 func (mb *KVBuffer) getIdx(key string) int {
 	for i, kv := range mb.kvs {
@@ -106,12 +232,21 @@ func (mb *KVBuffer) getInvalidIdx() int {
 	return -1
 }
 
+func (mb *KVBuffer) getInvalidOrKeyIdx(key string) int {
+	for i, kv := range mb.kvs {
+		if !kv.isValid() || key == b2s(mb.musttoken(kv.key)) {
+			return i
+		}
+	}
+	return -1
+}
+
 // reserve ensures need free bytes are available in the buffer, growing it when
 // permitted. It accounts for the byte-0 reservation on an empty buffer (see
 // mustAppendSlice). It returns false and sets flagOOMReached when the space
 // cannot be guaranteed: a tokint offset overflow, or a full buffer with
 // flagNoBufferGrow set.
-func (mb *KVBuffer) reserve(need int) bool {
+func (mb *KVBuffer) reserve(need int) (enoughSpace bool) {
 	if len(mb.buf) == 0 {
 		need++ // mustAppend* reserves byte 0 on an empty buffer.
 	}
@@ -130,24 +265,31 @@ func (mb *KVBuffer) reserve(need int) bool {
 }
 
 func (mb *KVBuffer) appendPair(key, value string) bool {
-	// reserve accounts for the byte-0 reservation mustAppendSlice makes on an
-	// empty buffer, and drops (flagging OOM) rather than panicking when growth
-	// is disabled and space runs out.
-
 	if !mb.canAddOneKV() || !mb.reserve(len(key)+len(value)) {
 		return false
 	}
-	k := mb.mustAppendSlice(key)
-	v := mb.mustAppendSlice(value)
-	debuglog("http:appendhdr:grow-hdrs")
+	mb.flags |= flagKVAppended
 	mb.kvs = append(mb.kvs, argsKV{
-		key:   k,
-		value: v,
+		key:   mb.mustAppendSlice(key),
+		value: mb.mustAppendSlice(value),
 	})
 	return true
 }
 
-func (mb *KVBuffer) canAddOneKV() bool {
+func (mb *KVBuffer) appendPairInt(key string, value int64, base int) bool {
+	vlen := internal.IntLen(value, base)
+	if !mb.canAddOneKV() || !mb.reserve(len(key)+vlen) {
+		return false
+	}
+	mb.flags |= flagKVAppended
+	mb.kvs = append(mb.kvs, argsKV{
+		key:   mb.mustAppendSlice(key),
+		value: mb.mustAppendInt(value, base),
+	})
+	return true
+}
+
+func (mb *KVBuffer) canAddOneKV() (enoughSpace bool) {
 	return len(mb.kvs) < cap(mb.kvs) || mb.flags&flagNoBufferGrow == 0
 }
 
@@ -161,7 +303,20 @@ func (mb *KVBuffer) mustAppendSlice(value string) headerSlice {
 	return mb.slice(mb.buf[L : L+len(value)])
 }
 
+func (hb *KVBuffer) mustAppendInt(value int64, base int) headerSlice {
+	L := len(hb.buf)
+	if L == 0 {
+		L++ // Valid key-values start after byte 0.
+	}
+	v := strconv.AppendInt(hb.buf[L:L], value, base)
+	hb.buf = hb.buf[:L+len(v)]
+	return hb.slice(hb.buf[L : L+len(v)])
+}
+
 func (mb *KVBuffer) slice(value []byte) headerSlice {
+	if value == nil {
+		return headerSlice{}
+	}
 	return bytes2tok(mb.buf, value)
 }
 
@@ -169,3 +324,32 @@ func (mb KVBuffer) musttoken(slice headerSlice) []byte {
 	return tok2bytes(mb.buf, slice)
 }
 func (mb *KVBuffer) noKV() argsKV { return argsKV{} }
+
+type tokint = uint16
+
+type headerSlice struct {
+	start tokint
+	len   tokint
+}
+
+type argsKV struct {
+	key   headerSlice
+	value headerSlice // value start >0 means value is present.
+}
+
+// isValid is for stores parsed in place, where offset 0 is the first key so
+// only length can signal presence. Empty keys are valid: see valueless cookies.
+func (kv argsKV) isValid() bool {
+	return kv.key.len > 0 || kv.value.len > 0
+}
+
+// isValidHeader is for the append-built [Header] store, where mustAppendSlice
+// burns byte 0 so a zero offset means absent. Drops offset-0 pairs otherwise.
+func (kv argsKV) isValidHeader() bool { return kv.key.start > 0 }
+
+func (kv *argsKV) invalidate() {
+	*kv = argsKV{}
+}
+
+// size is the buffer a pair occupies, used to pick the tightest slot to reuse.
+func (kv argsKV) size() int { return int(kv.key.len) + int(kv.value.len) }

http/httpraw/parse.go

@@ -49,42 +49,21 @@ var (
 const maxBufLen = 0xffff
 
 type headerBuf struct {
+	kv KVBuffer
 	// buf[:len] holds entire HTTP header data, which may be normalized by [flags]. buf[off:len] holds data not yet processed during parsing.
-	buf []byte
+	// buf []byte
 	// offset into buf for parsing.
 	off int
 	// args contains key-value store.
-	headers []argsKV
+	// headers []argsKV
 }
 
 // reset sets the buffer data and discards all parsed data. The field table is
 // grown to match the new buffer's capacity and never shrinks, so a header
 // reused across requests settles on its largest buffer and stops allocating.
 func (h *headerBuf) reset(buf []byte, numHeaderCapacity int) {
-	if buf == nil {
-		buf = h.buf[:0] // Reuse buffer but discard raw data on nil input.
-	}
-	if numHeaderCapacity != 0 {
-		internal.SliceReuse(&h.headers, numHeaderCapacity)
-	} else {
-		h.headers = h.headers[:0]
-	}
-	*h = headerBuf{
-		buf:     buf,
-		headers: h.headers,
-	}
-}
-
-type tokint = uint16
-
-type headerSlice struct {
-	start tokint
-	len   tokint
-}
-
-type argsKV struct {
-	key   headerSlice
-	value headerSlice // value start >0 means value is present.
+	h.kv.Reset(buf, numHeaderCapacity)
+	h.off = 0
 }
 
 type scannerState struct {
@@ -109,20 +88,22 @@ func (h *Header) parse(asResponse bool) (err error) {
 		return err
 	}
 	debuglog("http:firstline:done")
-	err = h.parseNextHeaders(h.flags)
+	err = h.parseNextHeaders(h.Flags())
 	debuglog("http:headers:done")
 	return err
 }
 
 func (h *Header) parseFirstLine(asResponse bool) (err error) {
-	if len(h.hbuf.buf) > maxBufLen {
+	if len(h.hbuf.kv.buf) > maxBufLen {
 		return errBufferTooLarge // Offsets would overflow uint16 tokint.
 	}
+	flags := h.Flags()
 	if asResponse {
-		h.statusCode, h.statusText, h.flags, err = h.hbuf.parseFirstLineResponse(h.flags)
+		h.statusCode, h.statusText, flags, err = h.hbuf.parseFirstLineResponse(flags)
 	} else {
-		h.method, h.requestTarget, h.proto, h.flags, err = h.hbuf.parseFirstLineRequest(h.flags)
+		h.method, h.requestTarget, h.proto, flags, err = h.hbuf.parseFirstLineRequest(flags)
 	}
+	h.hbuf.kv.flags = flags
 	return err
 }
 
@@ -130,39 +111,33 @@ func (h *Header) parseNextHeaders(flags Flags) error {
 	var ss scannerState
 	h.hbuf.parseNextHeaders(&ss, flags)
 	if ss.err != nil {
-		h.flags |= flagConnClose
+		h.hbuf.kv.flags |= flagConnClose
 		return ss.err
 	}
-	h.flags |= flagDoneParsingHeader
+	h.hbuf.kv.flags |= flagDoneParsingHeader
 	return nil
 }
 
-func (hb *headerBuf) readFromBytes(b []byte) {
-	hb.buf = append(hb.buf, b...)
-}
-
-func (hb *headerBuf) free() int { return cap(hb.buf) - len(hb.buf) }
+func (hb *headerBuf) free() int { return hb.kv.free() }
 
 func (hb *headerBuf) parseNextHeaders(ss *scannerState, flags Flags) {
 	debuglog("http:nexthdr:loop")
-	for kv := hb.next(ss); kv.isValid(); kv = hb.next(ss) {
-		if len(hb.headers) == cap(hb.headers) && flags.HasAny(flagNoBufferGrow) {
-			// Refuse to grow the headers slice: the caller granted this much
-			// memory and no more, see [Header.Reset].
+	for kv := hb.next(ss); kv.isValidHeader(); kv = hb.next(ss) {
+		if !hb.kv.canAddOneKV() {
 			ss.err = ErrHeaderTooMany
 			return
 		}
-		hb.headers = append(hb.headers, kv)
+		hb.kv.kvs = append(hb.kv.kvs, kv)
 	}
 	debuglog("http:nexthdr:done")
 }
 
 func (hb *headerBuf) offBuf() []byte {
-	return hb.buf[hb.off:]
+	return hb.kv.buf[hb.off:]
 }
 
 func (hb *headerBuf) skipLeadingCRLF() {
-	for hb.off < len(hb.buf) && (hb.buf[hb.off] == '\n' || hb.buf[hb.off] == '\r') {
+	for hb.off < len(hb.kv.buf) && (hb.kv.buf[hb.off] == '\n' || hb.kv.buf[hb.off] == '\r') {
 		hb.off++
 	}
 }
@@ -172,7 +147,7 @@ func (hb *headerBuf) scanLine() []byte {
 	if len(buf) > 0 && buf[len(buf)-1] == '\r' {
 		buf = buf[:len(buf)-1] // exclude carriage return.
 	}
-	if hb.off < len(hb.buf) {
+	if hb.off < len(hb.kv.buf) {
 		hb.off++ // consume newline.
 	}
 	return buf
@@ -206,8 +181,8 @@ func (hb *headerBuf) parseFirstLineRequest(initFlags Flags) (method, uri, proto
 	reqURIEnd := bytes.IndexByte(b[methodEnd+1:], ' ')
 	if reqURIEnd > 0 {
 		reqURIEnd += methodEnd + 1
-		uri = hb.slice(b[methodEnd+1 : reqURIEnd])
-		proto = hb.slice(b[reqURIEnd+1:]) // Skip space before protocol.
+		uri = hb.kv.slice(b[methodEnd+1 : reqURIEnd])
+		proto = hb.kv.slice(b[reqURIEnd+1:]) // Skip space before protocol.
 		if b2s(b[reqURIEnd+1:]) != strHTTP11 {
 			flags |= flagNoHTTP11
 		}
@@ -216,9 +191,9 @@ func (hb *headerBuf) parseFirstLineRequest(initFlags Flags) (method, uri, proto
 	} else {
 		// No version provided.
 		flags |= flagNoHTTP11
-		uri = hb.slice(b[methodEnd+1:])
+		uri = hb.kv.slice(b[methodEnd+1:])
 	}
-	method = hb.slice(b[:methodEnd])
+	method = hb.kv.slice(b[:methodEnd])
 	return method, uri, proto, flags, nil
 }
 
@@ -260,66 +235,19 @@ func (hb *headerBuf) parseFirstLineResponse(initFlags Flags) (statusCode, status
 			return statusCode, statusText, flags, errBadStatusCode
 		}
 	}
-	statusCode = hb.slice(code)
+	statusCode = hb.kv.slice(code)
 	if codeEnd < len(b) {
-		statusText = hb.slice(b[codeEnd+1:]) // Skip space before text.
+		statusText = hb.kv.slice(b[codeEnd+1:]) // Skip space before text.
 	}
 	debuglog("http:resp:done")
 	return statusCode, statusText, flags, nil
 }
 
-func (kv argsKV) isValid() bool {
-	return kv.key.start > 0
-}
-
-func (kv *argsKV) invalidate() {
-	*kv = argsKV{}
-}
-
-func (tb headerBuf) musttoken(slice headerSlice) []byte {
-	return tok2bytes(tb.buf, slice)
-
-}
-
-func (tb headerBuf) slice(b []byte) headerSlice {
-	return bytes2tok(tb.buf, b)
-}
-
 func (kv argsKV) HasValue() bool { return kv.value.start > 0 }
 
-func (h *Header) hasHeaderValue(key, value string) bool {
-	kv := h.peekHeader(key)
-	return kv.isValid() && b2s(h.hbuf.musttoken(kv.value)) == value
-}
-
-// peekHeader returns header key-value for the given key.
-//
-// The returned value is valid until the request is released,
-// either though ReleaseRequest or your request handler returning.
-// Do not store references to returned value. Make copies instead.
-func (h *Header) peekHeader(key string) argsKV {
-	hb := &h.hbuf
-	for i := 0; i < len(h.hbuf.headers); i++ {
-		if b2s(hb.musttoken(h.hbuf.headers[i].key)) == key {
-			return h.hbuf.headers[i]
-		}
-	}
-	return hb.noKV()
-}
-
-func (hb *headerBuf) mustAppendSlice(value string) headerSlice {
-	L := len(hb.buf)
-	if L == 0 {
-		L++ // Valid key-values start after 0.
-	}
-	copy(hb.buf[L:L+len(value)], value)
-	hb.buf = hb.buf[:L+len(value)]
-	return hb.slice(hb.buf[L : L+len(value)])
-}
-
 func (h *Header) reuseOrAppend(tok headerSlice, value string) headerSlice {
 	if tok.len > tokint(len(value)) {
-		copy(h.hbuf.musttoken(tok), value)
+		copy(h.hbuf.kv.musttoken(tok), value)
 		tok.len = tokint(len(value))
 		return tok
 	}
@@ -332,7 +260,7 @@ func (h *Header) appendSlice(value string) headerSlice {
 		return headerSlice{}
 	}
 	h.flags |= flagMangledBuffer
-	return h.hbuf.mustAppendSlice(value)
+	return h.hbuf.kv.mustAppendSlice(value)
 }
 
 func (h *Header) appendHeader(key, value string) {
@@ -437,7 +365,7 @@ func (hb *headerBuf) next(ss *scannerState) argsKV {
 		ss.nextColon = -1
 		ss.nextNewLine = -1
 	}
-	buf := hb.buf[hb.off:]
+	buf := hb.kv.buf[hb.off:]
 	blen := len(buf)
 	if blen >= 2 && buf[0] == '\r' && buf[1] == '\n' {
 		hb.off += 2
@@ -484,7 +412,7 @@ func (hb *headerBuf) next(ss *scannerState) argsKV {
 
 	// Ready to store key..
 	var resultKV argsKV
-	resultKV.key = hb.slice(buf[:n])
+	resultKV.key = hb.kv.slice(buf[:n])
 	n++ // consume colon.
 	for len(buf) > n && buf[n] == ' ' {
 		n++ // Trim leading spaces.
@@ -511,18 +439,19 @@ func (hb *headerBuf) next(ss *scannerState) argsKV {
 	if valueEnd > valueStart && buf[valueEnd-1] == '\r' {
 		valueEnd-- // Trim \r character if present before value.
 	}
-	resultKV.value = hb.slice(buf[valueStart:valueEnd])
+	resultKV.value = hb.kv.slice(buf[valueStart:valueEnd])
 	hb.off += n
 	return resultKV
 }
 
 // ConnectionClose returns true if 'Connection: close' header is set or if a invalid header was found.
 func (h *Header) ConnectionClose() bool {
-	closed := h.flags.HasAny(flagConnClose) ||
-		h.hasHeaderValue(headerConnection, strClose) ||
-		(h.flags.HasAny(flagNoHTTP11) && !h.hasHeaderValue(headerConnection, "keep-alive"))
+	flags := h.Flags()
+	closed := flags.HasAny(flagConnClose) ||
+		h.hbuf.kv.HasKeyValue(headerConnection, strClose) ||
+		(flags.HasAny(flagNoHTTP11) && !h.hbuf.kv.HasKeyValue(headerConnection, "keep-alive"))
 	if closed {
-		h.flags |= flagConnClose
+		h.hbuf.kv.flags |= flagConnClose
 	}
 	return closed
 }

http/httpraw/parse_test.go

@@ -331,6 +331,14 @@ func TestCookie_ParseBytes(t *testing.T) {
 	if string(c.Get("Path")) != "/" {
 		t.Errorf("Path = %q; want /", c.Get("Path"))
 	}
+	// The first pair sits at buffer offset 0, which a presence check keyed on
+	// the offset rather than the length reads as absent.
+	if string(c.Get("session")) != "abc123" {
+		t.Errorf("Get(session) = %q; want abc123", c.Get("session"))
+	}
+	if !c.HasKeyOrSingleValue("session") {
+		t.Error("expected first pair to be present by key")
+	}
 	if !c.HasKeyOrSingleValue("Secure") {
 		t.Error("expected Secure flag")
 	}