From 6076c17c517e1926b35330105e04c23ccc5900c9 Mon Sep 17 00:00:00 2001
From: Catherine <whitequark@whitequark.org>
Date: Fri, 5 Dec 2025 16:37:49 +0000
Subject: [PATCH] Rename HTTP negotiation items. NFC

---
 src/http.go  | 30 +++++++++++++++---------------
 src/pages.go | 14 ++++++++------
 2 files changed, 23 insertions(+), 21 deletions(-)

diff --git a/src/http.go b/src/http.go
index d6da818..4e6d1ef 100644
--- a/src/http.go
+++ b/src/http.go
@@ -8,7 +8,7 @@ import (
 	"strings"
 )
 
-var httpAcceptEncodingRegexp = regexp.MustCompile(`` +
+var httpAcceptRegexp = regexp.MustCompile(`` +
 	// token optionally prefixed by whitespace
 	`^[ \t]*([a-zA-Z0-9$!#$%&'*+.^_\x60|~-]+)` +
 	// quality value prefixed by a semicolon optionally surrounded by whitespace
@@ -17,22 +17,22 @@ var httpAcceptEncodingRegexp = regexp.MustCompile(`` +
 	`[ \t]*(?:,|$)`,
 )
 
-type httpEncoding struct {
+type httpAcceptOffer struct {
 	code string
 	qval float64
 }
 
-type httpEncodings struct {
-	encodings []httpEncoding
+type HTTPEncodings struct {
+	encodings []httpAcceptOffer
 }
 
-func parseHTTPEncodings(headerValue string) (result httpEncodings) {
+func ParseHTTPAcceptEncoding(headerValue string) (result HTTPEncodings) {
 	for headerValue != "" {
-		matches := httpAcceptEncodingRegexp.FindStringSubmatch(headerValue)
+		matches := httpAcceptRegexp.FindStringSubmatch(headerValue)
 		if matches == nil {
-			return httpEncodings{}
+			return HTTPEncodings{}
 		}
-		enc := httpEncoding{strings.ToLower(matches[1]), 1.0}
+		enc := httpAcceptOffer{strings.ToLower(matches[1]), 1.0}
 		if matches[2] != "" {
 			enc.qval, _ = strconv.ParseFloat(matches[2], 64)
 		}
@@ -51,9 +51,9 @@ func parseHTTPEncodings(headerValue string) (result httpEncodings) {
 
 // Negotiate returns the most preferred encoding that is acceptable by the
 // client, or an empty string if no encodings are acceptable.
-func (e *httpEncodings) Negotiate(codes ...string) string {
-	prefs := make(map[string]float64, len(codes))
-	for _, code := range codes {
+func (e *HTTPEncodings) Negotiate(offers ...string) string {
+	prefs := make(map[string]float64, len(offers))
+	for _, code := range offers {
 		prefs[code] = 0
 	}
 	implicitIdentity := true
@@ -73,11 +73,11 @@ func (e *httpEncodings) Negotiate(codes ...string) string {
 	if _, ok := prefs["identity"]; ok && implicitIdentity {
 		prefs["identity"] = -1 // sort last
 	}
-	encs := make([]httpEncoding, len(codes))
-	for idx, code := range codes {
-		encs[idx] = httpEncoding{code, prefs[code]}
+	encs := make([]httpAcceptOffer, len(offers))
+	for idx, code := range offers {
+		encs[idx] = httpAcceptOffer{code, prefs[code]}
 	}
-	slices.SortStableFunc(encs, func(a, b httpEncoding) int {
+	slices.SortStableFunc(encs, func(a, b httpAcceptOffer) int {
 		return -cmp.Compare(a.qval, b.qval)
 	})
 	for _, enc := range encs {
diff --git a/src/pages.go b/src/pages.go
index 85ad62b..6f43a03 100644
--- a/src/pages.go
+++ b/src/pages.go
@@ -214,7 +214,7 @@ func getPage(w http.ResponseWriter, r *http.Request) error {
 
 			// we only offer `/.git-pages/archive.tar` and not the `.tar.gz`/`.tar.zst` variants
 			// because HTTP can already request compression using the `Content-Encoding` mechanism
-			acceptedEncodings := parseHTTPEncodings(r.Header.Get("Accept-Encoding"))
+			acceptedEncodings := ParseHTTPAcceptEncoding(r.Header.Get("Accept-Encoding"))
 			negotiated := acceptedEncodings.Negotiate("zstd", "gzip", "identity")
 			if negotiated != "" {
 				w.Header().Set("Content-Encoding", negotiated)
@@ -322,11 +322,13 @@ func getPage(w http.ResponseWriter, r *http.Request) error {
 		defer closer.Close()
 	}
 
-	acceptedEncodings := parseHTTPEncodings(r.Header.Get("Accept-Encoding"))
+	offeredEncodings := []string{}
+	acceptedEncodings := ParseHTTPAcceptEncoding(r.Header.Get("Accept-Encoding"))
 	negotiatedEncoding := true
 	switch entry.GetTransform() {
 	case Transform_Identity:
-		switch acceptedEncodings.Negotiate("identity") {
+		offeredEncodings = []string{"identity"}
+		switch acceptedEncodings.Negotiate(offeredEncodings...) {
 		case "identity":
 			serveEncodingCount.
 				With(prometheus.Labels{"transform": "identity", "negotiated": "identity"}).
@@ -338,13 +340,13 @@ func getPage(w http.ResponseWriter, r *http.Request) error {
 				Inc()
 		}
 	case Transform_Zstd:
-		supported := []string{"zstd", "identity"}
+		offeredEncodings = []string{"zstd", "identity"}
 		if entry.ContentType == nil {
 			// If Content-Type is unset, `http.ServeContent` will try to sniff
 			// the file contents. That won't work if it's compressed.
-			supported = []string{"identity"}
+			offeredEncodings = []string{"identity"}
 		}
-		switch acceptedEncodings.Negotiate(supported...) {
+		switch acceptedEncodings.Negotiate(offeredEncodings...) {
 		case "zstd":
 			// Set Content-Length ourselves since `http.ServeContent` only sets
 			// it if Content-Encoding is unset or if it's a range request.