Upgrade to 0.12

1 files changed, 15 insertions, 5 deletions

diff --git a/vendor/golang.org/x/net/http2/headermap.go b/vendor/golang.org/x/net/http2/headermap.go
index c2805f6..c3ff3fa 100644
--- a/vendor/golang.org/x/net/http2/headermap.go
+++ b/vendor/golang.org/x/net/http2/headermap.go
@@ -7,15 +7,21 @@ package http2
 import (
         "net/http"
         "strings"
+        "sync"
 )
 
 var (
-        commonLowerHeader = map[string]string{} // Go-Canonical-Case -> lower-case
-        commonCanonHeader = map[string]string{} // lower-case -> Go-Canonical-Case
+        commonBuildOnce   sync.Once
+        commonLowerHeader map[string]string // Go-Canonical-Case -> lower-case
+        commonCanonHeader map[string]string // lower-case -> Go-Canonical-Case
 )
 
-func init() {
-        for _, v := range []string{
+func buildCommonHeaderMapsOnce() {
+        commonBuildOnce.Do(buildCommonHeaderMaps)
+}
+
+func buildCommonHeaderMaps() {
+        common := []string{
                 "accept",
                 "accept-charset",
                 "accept-encoding",
@@ -63,7 +69,10 @@ func init() {
                 "vary",
                 "via",
                 "www-authenticate",
-        } {
+        }
+        commonLowerHeader = make(map[string]string, len(common))
+        commonCanonHeader = make(map[string]string, len(common))
+        for _, v := range common {
                 chk := http.CanonicalHeaderKey(v)
                 commonLowerHeader[chk] = v
                 commonCanonHeader[v] = chk
@@ -71,6 +80,7 @@ func init() {
 }
 
 func lowerHeader(v string) string {
+        buildCommonHeaderMapsOnce()
         if s, ok := commonLowerHeader[v]; ok {
                 return s
         }