godoc: implement http.FileSystem for zip files

R=rsc, adg, bradfitz
CC=golang-dev
https://golang.org/cl/4750047

7 files changed, 252 insertions, 35 deletions

diff --git a/lib/godoc/dirlist.html b/lib/godoc/dirlist.html
index 3c1e3aae01..29b4b24357 100644
--- a/lib/godoc/dirlist.html
+++ b/lib/godoc/dirlist.html
@@ -18,11 +18,11 @@
 </tr>
 {.repeated section @}
 <tr>
-	<td align="left"><a href="{Name|html-esc}{@|dir/}">{Name|html-esc}{@|dir/}</a></td>
+	<td align="left"><a href="{@|fileInfoName}">{@|fileInfoName}</a></td>
 	<td></td>
-	<td align="right">{Size|html-esc}</td>
+	<td align="right">{@|fileInfoSize}</td>
 	<td></td>
-	<td align="left">{Mtime_ns|time}</td>
+	<td align="left">{@|fileInfoTime}</td>
 </tr>
 {.end}
 </table>
diff --git a/src/cmd/godoc/Makefile b/src/cmd/godoc/Makefile
index 69341fa4e6..f40d717030 100644
--- a/src/cmd/godoc/Makefile
+++ b/src/cmd/godoc/Makefile
@@ -11,6 +11,7 @@ GOFILES=\
 	filesystem.go\
 	format.go\
 	godoc.go\
+	httpzip.go\
 	index.go\
 	main.go\
 	mapping.go\
diff --git a/src/cmd/godoc/filesystem.go b/src/cmd/godoc/filesystem.go
index e9b5fe3c82..a68c085927 100644
--- a/src/cmd/godoc/filesystem.go
+++ b/src/cmd/godoc/filesystem.go
@@ -19,6 +19,7 @@ import (
 type FileInfo interface {
 	Name() string
 	Size() int64
+	Mtime_ns() int64
 	IsRegular() bool
 	IsDirectory() bool
 }
@@ -54,6 +55,10 @@ func (fi osFI) Size() int64 {
 	return fi.FileInfo.Size
 }
 
+func (fi osFI) Mtime_ns() int64 {
+	return fi.FileInfo.Mtime_ns
+}
+
 // osFS is the OS-specific implementation of FileSystem
 type osFS struct{}
 
diff --git a/src/cmd/godoc/godoc.go b/src/cmd/godoc/godoc.go
index 67441f304f..03ac1b98b7 100644
--- a/src/cmd/godoc/godoc.go
+++ b/src/cmd/godoc/godoc.go
@@ -67,11 +67,12 @@ var (
 	maxResults   = flag.Int("maxresults", 10000, "maximum number of full text search results shown")
 
 	// file system mapping
-	fs         FileSystem // the underlying file system
-	fsMap      Mapping    // user-defined mapping
-	fsTree     RWValue    // *Directory tree of packages, updated with each sync
-	pathFilter RWValue    // filter used when building fsMap directory trees
-	fsModified RWValue    // timestamp of last call to invalidateIndex
+	fs         FileSystem      // the underlying file system for godoc
+	fsHttp     http.FileSystem // the underlying file system for http
+	fsMap      Mapping         // user-defined mapping
+	fsTree     RWValue         // *Directory tree of packages, updated with each sync
+	pathFilter RWValue         // filter used when building fsMap directory trees
+	fsModified RWValue         // timestamp of last call to invalidateIndex
 
 	// http handlers
 	fileServer http.Handler // default file server
@@ -89,7 +90,7 @@ func initHandlers() {
 	}
 	fsMap.Init(paths)
 
-	fileServer = http.FileServer(http.Dir(*goroot))
+	fileServer = http.FileServer(fsHttp)
 	cmdHandler = httpHandler{"/cmd/", filepath.Join(*goroot, "src", "cmd"), false}
 	pkgHandler = httpHandler{"/pkg/", filepath.Join(*goroot, "src", "pkg"), true}
 }
@@ -565,22 +566,32 @@ func paddingFmt(w io.Writer, format string, x ...interface{}) {
 	}
 }
 
-// Template formatter for "time" format.
-func timeFmt(w io.Writer, format string, x ...interface{}) {
-	template.HTMLEscape(w, []byte(time.SecondsToLocalTime(x[0].(int64)/1e9).String()))
+// Template formatter for "localname" format.
+func localnameFmt(w io.Writer, format string, x ...interface{}) {
+	_, localname := filepath.Split(x[0].(string))
+	template.HTMLEscape(w, []byte(localname))
 }
 
-// Template formatter for "dir/" format.
-func dirslashFmt(w io.Writer, format string, x ...interface{}) {
-	if x[0].(FileInfo).IsDirectory() {
+// Template formatter for "fileInfoName" format.
+func fileInfoNameFmt(w io.Writer, format string, x ...interface{}) {
+	fi := x[0].(FileInfo)
+	template.HTMLEscape(w, []byte(fi.Name()))
+	if fi.IsDirectory() {
 		w.Write([]byte{'/'})
 	}
 }
 
-// Template formatter for "localname" format.
-func localnameFmt(w io.Writer, format string, x ...interface{}) {
-	_, localname := filepath.Split(x[0].(string))
-	template.HTMLEscape(w, []byte(localname))
+// Template formatter for "fileInfoSize" format.
+func fileInfoSizeFmt(w io.Writer, format string, x ...interface{}) {
+	fmt.Fprintf(w, "%d", x[0].(FileInfo).Size())
+}
+
+// Template formatter for "fileInfoTime" format.
+func fileInfoTimeFmt(w io.Writer, format string, x ...interface{}) {
+	if t := x[0].(FileInfo).Mtime_ns(); t != 0 {
+		template.HTMLEscape(w, []byte(time.SecondsToLocalTime(t/1e9).String()))
+	}
+	// don't print epoch if time is obviously not set
 }
 
 // Template formatter for "numlines" format.
@@ -601,8 +612,9 @@ var fmap = template.FormatterMap{
 	"infoLine":     infoLineFmt,
 	"infoSnippet":  infoSnippetFmt,
 	"padding":      paddingFmt,
-	"time":         timeFmt,
-	"dir/":         dirslashFmt,
+	"fileInfoName": fileInfoNameFmt,
+	"fileInfoSize": fileInfoSizeFmt,
+	"fileInfoTime": fileInfoTimeFmt,
 	"localname":    localnameFmt,
 	"numlines":     numlinesFmt,
 }
diff --git a/src/cmd/godoc/httpzip.go b/src/cmd/godoc/httpzip.go
new file mode 100644
index 0000000000..97d8569430
--- /dev/null
+++ b/src/cmd/godoc/httpzip.go
@@ -0,0 +1,184 @@
+// Copyright 2011 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.
+
+// This file provides an implementation of the http.FileSystem
+// interface based on the contents of a .zip file.
+//
+// Assumptions:
+//
+// - The file paths stored in the zip file must use a slash ('/') as path
+//   separator; and they must be relative (i.e., they must not start with
+//   a '/' - this is usually the case if the file was created w/o special
+//   options).
+// - The zip file system treats the file paths found in the zip internally
+//   like absolute paths w/o a leading '/'; i.e., the paths are considered
+//   relative to the root of the file system.
+// - All path arguments to file system methods must be absolute paths.
+
+// TODO(gri) Should define a commonly used FileSystem API that is the same
+//           for http and godoc. Then we only need one zip-file based file
+//           system implementation.
+
+package main
+
+import (
+	"archive/zip"
+	"fmt"
+	"http"
+	"io"
+	"os"
+	"path"
+	"sort"
+	"strings"
+)
+
+// We cannot import syscall on app engine.
+// TODO(gri) Once we have a truly abstract FileInfo implementation
+//           this won't be needed anymore.
+const (
+	S_IFDIR = 0x4000 // == syscall.S_IFDIR
+	S_IFREG = 0x8000 // == syscall.S_IFREG
+)
+
+// httpZipFile is the zip-file based implementation of http.File
+type httpZipFile struct {
+	info          os.FileInfo
+	io.ReadCloser // nil for directory
+	list          zipList
+}
+
+func (f *httpZipFile) Close() os.Error {
+	if f.info.IsRegular() {
+		return f.ReadCloser.Close()
+	}
+	f.list = nil
+	return nil
+}
+
+func (f *httpZipFile) Stat() (*os.FileInfo, os.Error) {
+	return &f.info, nil
+}
+
+func (f *httpZipFile) Readdir(count int) ([]os.FileInfo, os.Error) {
+	println("Readdir", f.info.Name)
+	if f.info.IsRegular() {
+		return nil, fmt.Errorf("Readdir called for regular file: %s", f.info.Name)
+	}
+
+	var list []os.FileInfo
+	dirname := zipPath(f.info.Name) + "/"
+	prevname := ""
+	for i, e := range f.list {
+		if count == 0 {
+			f.list = f.list[i:]
+			break
+		}
+		if !strings.HasPrefix(e.Name, dirname) {
+			f.list = nil
+			break // not in the same directory anymore
+		}
+		name := e.Name[len(dirname):] // local name
+		var mode uint32
+		var size, mtime_ns int64
+		if i := strings.IndexRune(name, '/'); i >= 0 {
+			// We infer directories from files in subdirectories.
+			// If we have x/y, return a directory entry for x.
+			name = name[0:i] // keep local directory name only
+			mode = S_IFDIR
+			// no size or mtime_ns for directories
+		} else {
+			mode = S_IFREG
+			size = int64(e.UncompressedSize)
+			mtime_ns = e.Mtime_ns()
+		}
+		// If we have x/y and x/z, don't return two directory entries for x.
+		// TODO(gri): It should be possible to do this more efficiently
+		// by determining the (fs.list) range of local directory entries
+		// (via two binary searches).
+		if name != prevname {
+			list = append(list, os.FileInfo{
+				Name:     name,
+				Mode:     mode,
+				Size:     size,
+				Mtime_ns: mtime_ns,
+			})
+			prevname = name
+			count--
+		}
+	}
+
+	if count >= 0 && len(list) == 0 {
+		return nil, os.EOF
+	}
+
+	return list, nil
+}
+
+func (f *httpZipFile) Read(buf []byte) (int, os.Error) {
+	if f.info.IsRegular() {
+		return f.ReadCloser.Read(buf)
+	}
+	return 0, fmt.Errorf("Read called for directory: %s", f.info.Name)
+}
+
+func (f *httpZipFile) Seek(offset int64, whence int) (int64, os.Error) {
+	return 0, fmt.Errorf("Seek not implemented for zip file entry: %s", f.info.Name)
+}
+
+// httpZipFS is the zip-file based implementation of http.FileSystem
+type httpZipFS struct {
+	*zip.ReadCloser
+	list zipList
+	root string
+}
+
+func (fs *httpZipFS) Open(abspath string) (http.File, os.Error) {
+	name := path.Join(fs.root, abspath)
+	index := fs.list.lookup(name)
+	if index < 0 {
+		return nil, fmt.Errorf("file not found: %s", abspath)
+	}
+
+	if f := fs.list[index]; f.Name == name {
+		// exact match found - must be a file
+		rc, err := f.Open()
+		if err != nil {
+			return nil, err
+		}
+		return &httpZipFile{
+			os.FileInfo{
+				Name:     abspath,
+				Mode:     S_IFREG,
+				Size:     int64(f.UncompressedSize),
+				Mtime_ns: f.Mtime_ns(),
+			},
+			rc,
+			nil,
+		}, nil
+	}
+
+	// not an exact match - must be a directory
+	println("opened directory", abspath, len(fs.list[index:]))
+	return &httpZipFile{
+		os.FileInfo{
+			Name: abspath,
+			Mode: S_IFDIR,
+			// no size or mtime_ns for directories
+		},
+		nil,
+		fs.list[index:],
+	}, nil
+}
+
+func (fs *httpZipFS) Close() os.Error {
+	fs.list = nil
+	return fs.ReadCloser.Close()
+}
+
+func NewHttpZipFS(rc *zip.ReadCloser, root string) http.FileSystem {
+	list := make(zipList, len(rc.File))
+	copy(list, rc.File) // sort a copy of rc.File
+	sort.Sort(list)
+	return &httpZipFS{rc, list, zipPath(root)}
+}
diff --git a/src/cmd/godoc/main.go b/src/cmd/godoc/main.go
index f984719659..6f7d9d78dc 100644
--- a/src/cmd/godoc/main.go
+++ b/src/cmd/godoc/main.go
@@ -49,7 +49,7 @@ const defaultAddr = ":6060" // default webserver address
 
 var (
 	// file system to serve
-	// (with e.g.: zip -r go.zip $GOROOT -i \*.go -i \*.html -i \*.css -i \*.js -i \*.txt -i \*.c -i \*.h -i \*.s -i \*.png -i \*.jpg -i \*.sh)
+	// (with e.g.: zip -r go.zip $GOROOT -i \*.go -i \*.html -i \*.css -i \*.js -i \*.txt -i \*.c -i \*.h -i \*.s -i \*.png -i \*.jpg -i \*.sh -i favicon.ico)
 	zipfile = flag.String("zip", "", "zip file providing the file system to serve; disabled if empty")
 
 	// periodic sync
@@ -219,26 +219,34 @@ func main() {
 	flag.Usage = usage
 	flag.Parse()
 
+	// Check usage: either server and no args, or command line and args
+	if (*httpAddr != "") != (flag.NArg() == 0) {
+		usage()
+	}
+
+	if *tabwidth < 0 {
+		log.Fatalf("negative tabwidth %d", *tabwidth)
+	}
+
 	// Clean goroot: normalize path separator.
 	*goroot = filepath.Clean(*goroot)
 
 	// Determine file system to use.
-	fs = OS
-	if *zipfile != "" {
+	// TODO(gri) - fs and fsHttp should really be the same. Try to unify.
+	//           - fsHttp doesn't need to be set up in command-line mode,
+	//             same is true for the http handlers in initHandlers.
+	if *zipfile == "" {
+		// use file system of underlying OS
+		fs = OS
+		fsHttp = http.Dir(*goroot)
+	} else {
+		// use file system specified via .zip file
 		rc, err := zip.OpenReader(*zipfile)
 		if err != nil {
 			log.Fatalf("%s: %s\n", *zipfile, err)
 		}
 		fs = NewZipFS(rc)
-	}
-
-	// Check usage: either server and no args, or command line and args
-	if (*httpAddr != "") != (flag.NArg() == 0) {
-		usage()
-	}
-
-	if *tabwidth < 0 {
-		log.Fatalf("negative tabwidth %d", *tabwidth)
+		fsHttp = NewHttpZipFS(rc, *goroot)
 	}
 
 	initHandlers()
diff --git a/src/cmd/godoc/zip.go b/src/cmd/godoc/zip.go
index b2257998d7..eac6992387 100644
--- a/src/cmd/godoc/zip.go
+++ b/src/cmd/godoc/zip.go
@@ -40,12 +40,19 @@ func (fi zipFI) Name() string {
 }
 
 func (fi zipFI) Size() int64 {
-	if fi.file != nil {
-		return int64(fi.file.UncompressedSize)
+	if f := fi.file; f != nil {
+		return int64(f.UncompressedSize)
 	}
 	return 0 // directory
 }
 
+func (fi zipFI) Mtime_ns() int64 {
+	if f := fi.file; f != nil {
+		return f.Mtime_ns()
+	}
+	return 0 // directory has no modified time entry
+}
+
 func (fi zipFI) IsDirectory() bool {
 	return fi.file == nil
 }