1 files changed, 211 insertions, 0 deletions
diff --git a/src/net/http/header.go b/src/net/http/header.go
new file mode 100644
index 000000000..153b94370
--- /dev/null
+++ b/src/net/http/header.go
@@ -0,0 +1,211 @@
+// Copyright 2010 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package http
+
+import (
+	"io"
+	"net/textproto"
+	"sort"
+	"strings"
+	"sync"
+	"time"
+)
+
+var raceEnabled = false // set by race.go
+
+// A Header represents the key-value pairs in an HTTP header.
+type Header map[string][]string
+
+// Add adds the key, value pair to the header.
+// It appends to any existing values associated with key.
+func (h Header) Add(key, value string) {
+	textproto.MIMEHeader(h).Add(key, value)
+}
+
+// Set sets the header entries associated with key to
+// the single element value.  It replaces any existing
+// values associated with key.
+func (h Header) Set(key, value string) {
+	textproto.MIMEHeader(h).Set(key, value)
+}
+
+// Get gets the first value associated with the given key.
+// If there are no values associated with the key, Get returns "".
+// To access multiple values of a key, access the map directly
+// with CanonicalHeaderKey.
+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)
+}
+
+// Write writes a header in wire format.
+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
+}
+
+// A headerSorter implements sort.Interface by sorting a []keyValues
+// by key. It's used as a pointer, so it can fit in a sort.Interface
+// interface value without allocation.
+type headerSorter struct {
+	kvs []keyValues
+}
+
+func (s *headerSorter) Len() int           { return len(s.kvs) }
+func (s *headerSorter) Swap(i, j int)      { s.kvs[i], s.kvs[j] = s.kvs[j], s.kvs[i] }
+func (s *headerSorter) Less(i, j int) bool { return s.kvs[i].key < s.kvs[j].key }
+
+var headerSorterPool = sync.Pool{
+	New: func() interface{} { return new(headerSorter) },
+}
+
+// sortedKeyValues returns h's keys sorted in the returned kvs
+// slice. The headerSorter used to sort is also returned, for possible
+// return to headerSorterCache.
+func (h Header) sortedKeyValues(exclude map[string]bool) (kvs []keyValues, hs *headerSorter) {
+	hs = headerSorterPool.Get().(*headerSorter)
+	if cap(hs.kvs) < len(h) {
+		hs.kvs = make([]keyValues, 0, len(h))
+	}
+	kvs = hs.kvs[:0]
+	for k, vv := range h {
+		if !exclude[k] {
+			kvs = append(kvs, keyValues{k, vv})
+		}
+	}
+	hs.kvs = kvs
+	sort.Sort(hs)
+	return kvs, hs
+}
+
+// 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 {
+	ws, ok := w.(writeStringer)
+	if !ok {
+		ws = stringWriter{w}
+	}
+	kvs, sorter := h.sortedKeyValues(exclude)
+	for _, kv := range kvs {
+		for _, v := range kv.values {
+			v = headerNewlineToSpace.Replace(v)
+			v = textproto.TrimString(v)
+			for _, s := range []string{kv.key, ": ", v, "\r\n"} {
+				if _, err := ws.WriteString(s); err != nil {
+					return err
+				}
+			}
+		}
+	}
+	headerSorterPool.Put(sorter)
+	return nil
+}
+
+// CanonicalHeaderKey returns the canonical format of the
+// header key s.  The canonicalization converts the first
+// letter and any letter following a hyphen to upper case;
+// 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 reports 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'
+}