1 files changed, 123 insertions, 12 deletions
diff --git a/src/pkg/net/http/header.go b/src/pkg/net/http/header.go
index b107c312d..f479b7b4e 100644
--- a/src/pkg/net/http/header.go
+++ b/src/pkg/net/http/header.go
@@ -5,11 +5,11 @@
 package http
 
 import (
-	"fmt"
 	"io"
 	"net/textproto"
 	"sort"
 	"strings"
+	"time"
 )
 
 // A Header represents the key-value pairs in an HTTP header.
@@ -36,6 +36,14 @@ func (h Header) Get(key string) string {
 	return textproto.MIMEHeader(h).Get(key)
 }
 
+// get is like Get, but key must already be in CanonicalHeaderKey form.
+func (h Header) get(key string) string {
+	if v := h[key]; len(v) > 0 {
+		return v[0]
+	}
+	return ""
+}
+
 // Del deletes the values associated with key.
 func (h Header) Del(key string) {
 	textproto.MIMEHeader(h).Del(key)
@@ -46,24 +54,87 @@ func (h Header) Write(w io.Writer) error {
 	return h.WriteSubset(w, nil)
 }
 
+func (h Header) clone() Header {
+	h2 := make(Header, len(h))
+	for k, vv := range h {
+		vv2 := make([]string, len(vv))
+		copy(vv2, vv)
+		h2[k] = vv2
+	}
+	return h2
+}
+
+var timeFormats = []string{
+	TimeFormat,
+	time.RFC850,
+	time.ANSIC,
+}
+
+// ParseTime parses a time header (such as the Date: header),
+// trying each of the three formats allowed by HTTP/1.1:
+// TimeFormat, time.RFC850, and time.ANSIC.
+func ParseTime(text string) (t time.Time, err error) {
+	for _, layout := range timeFormats {
+		t, err = time.Parse(layout, text)
+		if err == nil {
+			return
+		}
+	}
+	return
+}
+
 var headerNewlineToSpace = strings.NewReplacer("\n", " ", "\r", " ")
 
+type writeStringer interface {
+	WriteString(string) (int, error)
+}
+
+// stringWriter implements WriteString on a Writer.
+type stringWriter struct {
+	w io.Writer
+}
+
+func (w stringWriter) WriteString(s string) (n int, err error) {
+	return w.w.Write([]byte(s))
+}
+
+type keyValues struct {
+	key    string
+	values []string
+}
+
+type byKey []keyValues
+
+func (s byKey) Len() int           { return len(s) }
+func (s byKey) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
+func (s byKey) Less(i, j int) bool { return s[i].key < s[j].key }
+
+func (h Header) sortedKeyValues(exclude map[string]bool) []keyValues {
+	kvs := make([]keyValues, 0, len(h))
+	for k, vv := range h {
+		if !exclude[k] {
+			kvs = append(kvs, keyValues{k, vv})
+		}
+	}
+	sort.Sort(byKey(kvs))
+	return kvs
+}
+
 // WriteSubset writes a header in wire format.
 // If exclude is not nil, keys where exclude[key] == true are not written.
 func (h Header) WriteSubset(w io.Writer, exclude map[string]bool) error {
-	keys := make([]string, 0, len(h))
-	for k := range h {
-		if exclude == nil || !exclude[k] {
-			keys = append(keys, k)
-		}
+	ws, ok := w.(writeStringer)
+	if !ok {
+		ws = stringWriter{w}
 	}
-	sort.Strings(keys)
-	for _, k := range keys {
-		for _, v := range h[k] {
+	for _, kv := range h.sortedKeyValues(exclude) {
+		for _, v := range kv.values {
 			v = headerNewlineToSpace.Replace(v)
-			v = strings.TrimSpace(v)
-			if _, err := fmt.Fprintf(w, "%s: %s\r\n", k, v); err != nil {
-				return err
+			v = textproto.TrimString(v)
+			for _, s := range []string{kv.key, ": ", v, "\r\n"} {
+				if _, err := ws.WriteString(s); err != nil {
+					return err
+				}
 			}
 		}
 	}
@@ -76,3 +147,43 @@ func (h Header) WriteSubset(w io.Writer, exclude map[string]bool) error {
 // the rest are converted to lowercase.  For example, the
 // canonical key for "accept-encoding" is "Accept-Encoding".
 func CanonicalHeaderKey(s string) string { return textproto.CanonicalMIMEHeaderKey(s) }
+
+// hasToken returns whether token appears with v, ASCII
+// case-insensitive, with space or comma boundaries.
+// token must be all lowercase.
+// v may contain mixed cased.
+func hasToken(v, token string) bool {
+	if len(token) > len(v) || token == "" {
+		return false
+	}
+	if v == token {
+		return true
+	}
+	for sp := 0; sp <= len(v)-len(token); sp++ {
+		// Check that first character is good.
+		// The token is ASCII, so checking only a single byte
+		// is sufficient.  We skip this potential starting
+		// position if both the first byte and its potential
+		// ASCII uppercase equivalent (b|0x20) don't match.
+		// False positives ('^' => '~') are caught by EqualFold.
+		if b := v[sp]; b != token[0] && b|0x20 != token[0] {
+			continue
+		}
+		// Check that start pos is on a valid token boundary.
+		if sp > 0 && !isTokenBoundary(v[sp-1]) {
+			continue
+		}
+		// Check that end pos is on a valid token boundary.
+		if endPos := sp + len(token); endPos != len(v) && !isTokenBoundary(v[endPos]) {
+			continue
+		}
+		if strings.EqualFold(v[sp:sp+len(token)], token) {
+			return true
+		}
+	}
+	return false
+}
+
+func isTokenBoundary(b byte) bool {
+	return b == ' ' || b == ',' || b == '\t'
+}