Create a new FrameHeader for each comparison

This saves some initialization time.

Signed-off-by: Oleg Zaytsev <[email protected]>

Author: colega

Diff for: http2/frame.go

@@ -225,15 +225,10 @@ var fhBytes = sync.Pool{
 	},
 }
 
-var invalidHTTP1LookingFrameHeader = func() FrameHeader {
-	fh, err := readFrameHeader(make([]byte, frameHeaderLen), strings.NewReader("HTTP/1.1 "))
-	if err != nil {
-		panic(err)
-	}
+func invalidHTTP1LookingFrameHeader() FrameHeader {
+	fh, _ := readFrameHeader(make([]byte, frameHeaderLen), strings.NewReader("HTTP/1.1 "))
 	return fh
-}()
-
-func (h FrameHeader) looksLikeHTTP1Header() bool { return h == invalidHTTP1LookingFrameHeader }
+}
 
 // ReadFrameHeader reads 9 bytes from r and returns a FrameHeader.
 // Most users should use Framer.ReadFrame instead.
@@ -513,14 +508,14 @@ func (fr *Framer) ReadFrame() (Frame, error) {
 		return nil, err
 	}
 	if fh.Length > fr.maxReadSize {
-		if fh.looksLikeHTTP1Header() {
+		if fh == invalidHTTP1LookingFrameHeader() {
 			return nil, fmt.Errorf("http2: failed reading the frame payload: %w, note that the frame header looked like an HTTP/1.1 header", err)
 		}
 		return nil, ErrFrameTooLarge
 	}
 	payload := fr.getReadBuf(fh.Length)
 	if _, err := io.ReadFull(fr.r, payload); err != nil {
-		if fh.looksLikeHTTP1Header() {
+		if fh == invalidHTTP1LookingFrameHeader() {
 			return nil, fmt.Errorf("http2: failed reading the frame payload: %w, note that the frame header looked like an HTTP/1.1 header", err)
 		}
 		return nil, err

Diff for: http2/frame_test.go

@@ -626,27 +626,6 @@ func TestReadFrameHeader(t *testing.T) {
 	}
 }
 
-func TestReadFrameHeader_FromHTTP1Header(t *testing.T) {
-	tests := []struct {
-		in             string
-		looksLikeHTTP1 bool
-	}{
-		// Ignore high bit:
-		{in: "\xff\xff\xff" + "\xff" + "\xff" + "\xff\xff\xff\xff", looksLikeHTTP1: false},
-		{in: "HTTP/1.1 400 Bad Request\r\n", looksLikeHTTP1: true},
-	}
-	for i, tt := range tests {
-		got, err := readFrameHeader(make([]byte, 9), strings.NewReader(tt.in))
-		if err != nil {
-			t.Errorf("%d. readFrameHeader(%q) = %v", i, tt.in, err)
-			continue
-		}
-		if got.looksLikeHTTP1Header() != tt.looksLikeHTTP1 {
-			t.Errorf("%d. readFrameHeader(%q).looksLikeHTTP1Header = %v; want %v", i, tt.in, got.looksLikeHTTP1Header(), tt.looksLikeHTTP1)
-		}
-	}
-}
-
 func TestReadWriteFrameHeader(t *testing.T) {
 	tests := []struct {
 		len      uint32