libgo: Update to weekly 2011-11-09.

From-SVN: r182073

1 files changed, 324 insertions, 0 deletions

diff --git a/libgo/go/net/http/fs.go b/libgo/go/net/http/fs.go
new file mode 100644
index 0000000..5f91ff5
--- /dev/null
+++ b/libgo/go/net/http/fs.go
@@ -0,0 +1,324 @@
+// Copyright 2009 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.
+
+// HTTP file system request handler
+
+package http
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"mime"
+	"os"
+	"path"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"time"
+	"unicode/utf8"
+)
+
+// A Dir implements http.FileSystem using the native file
+// system restricted to a specific directory tree.
+type Dir string
+
+func (d Dir) Open(name string) (File, error) {
+	if filepath.Separator != '/' && strings.IndexRune(name, filepath.Separator) >= 0 {
+		return nil, errors.New("http: invalid character in file path")
+	}
+	f, err := os.Open(filepath.Join(string(d), filepath.FromSlash(path.Clean("/"+name))))
+	if err != nil {
+		return nil, err
+	}
+	return f, nil
+}
+
+// A FileSystem implements access to a collection of named files.
+// The elements in a file path are separated by slash ('/', U+002F)
+// characters, regardless of host operating system convention.
+type FileSystem interface {
+	Open(name string) (File, error)
+}
+
+// A File is returned by a FileSystem's Open method and can be
+// served by the FileServer implementation.
+type File interface {
+	Close() error
+	Stat() (*os.FileInfo, error)
+	Readdir(count int) ([]os.FileInfo, error)
+	Read([]byte) (int, error)
+	Seek(offset int64, whence int) (int64, error)
+}
+
+// Heuristic: b is text if it is valid UTF-8 and doesn't
+// contain any unprintable ASCII or Unicode characters.
+func isText(b []byte) bool {
+	for len(b) > 0 && utf8.FullRune(b) {
+		rune, size := utf8.DecodeRune(b)
+		if size == 1 && rune == utf8.RuneError {
+			// decoding error
+			return false
+		}
+		if 0x7F <= rune && rune <= 0x9F {
+			return false
+		}
+		if rune < ' ' {
+			switch rune {
+			case '\n', '\r', '\t':
+				// okay
+			default:
+				// binary garbage
+				return false
+			}
+		}
+		b = b[size:]
+	}
+	return true
+}
+
+func dirList(w ResponseWriter, f File) {
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	fmt.Fprintf(w, "<pre>\n")
+	for {
+		dirs, err := f.Readdir(100)
+		if err != nil || len(dirs) == 0 {
+			break
+		}
+		for _, d := range dirs {
+			name := d.Name
+			if d.IsDirectory() {
+				name += "/"
+			}
+			// TODO htmlescape
+			fmt.Fprintf(w, "<a href=\"%s\">%s</a>\n", name, name)
+		}
+	}
+	fmt.Fprintf(w, "</pre>\n")
+}
+
+// name is '/'-separated, not filepath.Separator.
+func serveFile(w ResponseWriter, r *Request, fs FileSystem, name string, redirect bool) {
+	const indexPage = "/index.html"
+
+	// redirect .../index.html to .../
+	// can't use Redirect() because that would make the path absolute,
+	// which would be a problem running under StripPrefix
+	if strings.HasSuffix(r.URL.Path, indexPage) {
+		localRedirect(w, r, "./")
+		return
+	}
+
+	f, err := fs.Open(name)
+	if err != nil {
+		// TODO expose actual error?
+		NotFound(w, r)
+		return
+	}
+	defer f.Close()
+
+	d, err1 := f.Stat()
+	if err1 != nil {
+		// TODO expose actual error?
+		NotFound(w, r)
+		return
+	}
+
+	if redirect {
+		// redirect to canonical path: / at end of directory url
+		// r.URL.Path always begins with /
+		url := r.URL.Path
+		if d.IsDirectory() {
+			if url[len(url)-1] != '/' {
+				localRedirect(w, r, path.Base(url)+"/")
+				return
+			}
+		} else {
+			if url[len(url)-1] == '/' {
+				localRedirect(w, r, "../"+path.Base(url))
+				return
+			}
+		}
+	}
+
+	if t, _ := time.Parse(TimeFormat, r.Header.Get("If-Modified-Since")); t != nil && d.Mtime_ns/1e9 <= t.Seconds() {
+		w.WriteHeader(StatusNotModified)
+		return
+	}
+	w.Header().Set("Last-Modified", time.SecondsToUTC(d.Mtime_ns/1e9).Format(TimeFormat))
+
+	// use contents of index.html for directory, if present
+	if d.IsDirectory() {
+		index := name + indexPage
+		ff, err := fs.Open(index)
+		if err == nil {
+			defer ff.Close()
+			dd, err := ff.Stat()
+			if err == nil {
+				name = index
+				d = dd
+				f = ff
+			}
+		}
+	}
+
+	if d.IsDirectory() {
+		dirList(w, f)
+		return
+	}
+
+	// serve file
+	size := d.Size
+	code := StatusOK
+
+	// If Content-Type isn't set, use the file's extension to find it.
+	if w.Header().Get("Content-Type") == "" {
+		ctype := mime.TypeByExtension(filepath.Ext(name))
+		if ctype == "" {
+			// read a chunk to decide between utf-8 text and binary
+			var buf [1024]byte
+			n, _ := io.ReadFull(f, buf[:])
+			b := buf[:n]
+			if isText(b) {
+				ctype = "text/plain; charset=utf-8"
+			} else {
+				// generic binary
+				ctype = "application/octet-stream"
+			}
+			f.Seek(0, os.SEEK_SET) // rewind to output whole file
+		}
+		w.Header().Set("Content-Type", ctype)
+	}
+
+	// handle Content-Range header.
+	// TODO(adg): handle multiple ranges
+	ranges, err := parseRange(r.Header.Get("Range"), size)
+	if err == nil && len(ranges) > 1 {
+		err = errors.New("multiple ranges not supported")
+	}
+	if err != nil {
+		Error(w, err.Error(), StatusRequestedRangeNotSatisfiable)
+		return
+	}
+	if len(ranges) == 1 {
+		ra := ranges[0]
+		if _, err := f.Seek(ra.start, os.SEEK_SET); err != nil {
+			Error(w, err.Error(), StatusRequestedRangeNotSatisfiable)
+			return
+		}
+		size = ra.length
+		code = StatusPartialContent
+		w.Header().Set("Content-Range", fmt.Sprintf("bytes %d-%d/%d", ra.start, ra.start+ra.length-1, d.Size))
+	}
+
+	w.Header().Set("Accept-Ranges", "bytes")
+	if w.Header().Get("Content-Encoding") == "" {
+		w.Header().Set("Content-Length", strconv.Itoa64(size))
+	}
+
+	w.WriteHeader(code)
+
+	if r.Method != "HEAD" {
+		io.CopyN(w, f, size)
+	}
+}
+
+// localRedirect gives a Moved Permanently response.
+// It does not convert relative paths to absolute paths like Redirect does.
+func localRedirect(w ResponseWriter, r *Request, newPath string) {
+	if q := r.URL.RawQuery; q != "" {
+		newPath += "?" + q
+	}
+	w.Header().Set("Location", newPath)
+	w.WriteHeader(StatusMovedPermanently)
+}
+
+// ServeFile replies to the request with the contents of the named file or directory.
+func ServeFile(w ResponseWriter, r *Request, name string) {
+	dir, file := filepath.Split(name)
+	serveFile(w, r, Dir(dir), file, false)
+}
+
+type fileHandler struct {
+	root FileSystem
+}
+
+// FileServer returns a handler that serves HTTP requests
+// with the contents of the file system rooted at root.
+//
+// To use the operating system's file system implementation,
+// use http.Dir:
+//
+//     http.Handle("/", http.FileServer(http.Dir("/tmp")))
+func FileServer(root FileSystem) Handler {
+	return &fileHandler{root}
+}
+
+func (f *fileHandler) ServeHTTP(w ResponseWriter, r *Request) {
+	upath := r.URL.Path
+	if !strings.HasPrefix(upath, "/") {
+		upath = "/" + upath
+		r.URL.Path = upath
+	}
+	serveFile(w, r, f.root, path.Clean(upath), true)
+}
+
+// httpRange specifies the byte range to be sent to the client.
+type httpRange struct {
+	start, length int64
+}
+
+// parseRange parses a Range header string as per RFC 2616.
+func parseRange(s string, size int64) ([]httpRange, error) {
+	if s == "" {
+		return nil, nil // header not present
+	}
+	const b = "bytes="
+	if !strings.HasPrefix(s, b) {
+		return nil, errors.New("invalid range")
+	}
+	var ranges []httpRange
+	for _, ra := range strings.Split(s[len(b):], ",") {
+		i := strings.Index(ra, "-")
+		if i < 0 {
+			return nil, errors.New("invalid range")
+		}
+		start, end := ra[:i], ra[i+1:]
+		var r httpRange
+		if start == "" {
+			// If no start is specified, end specifies the
+			// range start relative to the end of the file.
+			i, err := strconv.Atoi64(end)
+			if err != nil {
+				return nil, errors.New("invalid range")
+			}
+			if i > size {
+				i = size
+			}
+			r.start = size - i
+			r.length = size - r.start
+		} else {
+			i, err := strconv.Atoi64(start)
+			if err != nil || i > size || i < 0 {
+				return nil, errors.New("invalid range")
+			}
+			r.start = i
+			if end == "" {
+				// If no end is specified, range extends to end of the file.
+				r.length = size - r.start
+			} else {
+				i, err := strconv.Atoi64(end)
+				if err != nil || r.start > i {
+					return nil, errors.New("invalid range")
+				}
+				if i >= size {
+					i = size - 1
+				}
+				r.length = i - r.start + 1
+			}
+		}
+		ranges = append(ranges, r)
+	}
+	return ranges, nil
+}