fix: Status Line parsing and writing (#1135)

* Adding zero-allocation uint64 to byte slice conversion and fixing the ResponseHeader.SetStatusLine function call signature

* Removing unnecessary i2b function

* Fixing various bugs

* Adding test cases

* Commenting AppendStatusLine

* Update status.go

Co-authored-by: Erik Dubbelboer <erik@dubbelboer.com>

* Update header.go

Co-authored-by: Erik Dubbelboer <erik@dubbelboer.com>

* Cleaning up references to strHTTP11, using formatStatusLine for invalidStatusLine, and making `appendStatusLine` an unexported function

Issue: https://github.com/valyala/fasthttp/issues/1132

* Fixing merge conflicts

Issue: https://github.com/valyala/fasthttp/issues/1132

* Replacing []byte{} with nil in some test cases

Issue: https://github.com/valyala/fasthttp/issues/1132

* Cleaning up parsing first line, and improving StatusMessage function

Issue: https://github.com/valyala/fasthttp/issues/1132

* Fixing as per PR

* Update header.go

Co-authored-by: Erik Dubbelboer <erik@dubbelboer.com>

* Update header.go

Co-authored-by: Erik Dubbelboer <erik@dubbelboer.com>

* Fixing as per requested changes

* Update header_test.go

Co-authored-by: Erik Dubbelboer <erik@dubbelboer.com>

Co-authored-by: Erik Dubbelboer <erik@dubbelboer.com>

1 files changed, 15 insertions, 31 deletions

diff --git a/status.go b/status.go
index 28d1286..c88ba11 100644
--- a/status.go
+++ b/status.go
@@ -1,7 +1,6 @@
 package fasthttp
 
 import (
-	"fmt"
 	"strconv"
 )
 
@@ -81,7 +80,7 @@ const (
 )
 
 var (
-	statusLines = make([][]byte, statusMessageMax+1)
+	unknownStatusCode = "Unknown Status Code"
 
 	statusMessages = []string{
 		StatusContinue:           "Continue",
@@ -155,39 +154,24 @@ var (
 // StatusMessage returns HTTP status message for the given status code.
 func StatusMessage(statusCode int) string {
 	if statusCode < statusMessageMin || statusCode > statusMessageMax {
-		return "Unknown Status Code"
+		return unknownStatusCode
 	}
 
-	s := statusMessages[statusCode]
-	if s == "" {
-		s = "Unknown Status Code"
+	if s := statusMessages[statusCode]; s != "" {
+		return s
 	}
-	return s
+	return unknownStatusCode
 }
 
-func init() {
-	// Fill all valid status lines
-	for i := 0; i < len(statusLines); i++ {
-		statusLines[i] = []byte(fmt.Sprintf("HTTP/1.1 %d %s\r\n", i, StatusMessage(i)))
+func formatStatusLine(dst []byte, protocol []byte, statusCode int, statusText []byte) []byte {
+	dst = append(dst, protocol...)
+	dst = append(dst, ' ')
+	dst = strconv.AppendInt(dst, int64(statusCode), 10)
+	dst = append(dst, ' ')
+	if len(statusText) == 0 {
+		dst = append(dst, s2b(StatusMessage(statusCode))...)
+	} else {
+		dst = append(dst, statusText...)
 	}
-}
-
-func statusLine(statusCode int) []byte {
-	if statusCode < 0 || statusCode > statusMessageMax {
-		return invalidStatusLine(statusCode)
-	}
-
-	return statusLines[statusCode]
-}
-
-func invalidStatusLine(statusCode int) []byte {
-	statusText := StatusMessage(statusCode)
-	// xxx placeholder of status code
-	var line = make([]byte, 0, len("HTTP/1.1 xxx \r\n")+len(statusText))
-	line = append(line, "HTTP/1.1 "...)
-	line = strconv.AppendInt(line, int64(statusCode), 10)
-	line = append(line, ' ')
-	line = append(line, statusText...)
-	line = append(line, "\r\n"...)
-	return line
+	return append(dst, strCRLF...)
 }