1 files changed, 181 insertions, 0 deletions
diff --git a/src/cmd/godoc/httpzip.go b/src/cmd/godoc/httpzip.go
new file mode 100644
index 000000000..cb8322ee4
--- /dev/null
+++ b/src/cmd/godoc/httpzip.go
@@ -0,0 +1,181 @@
+// 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 are considered relative to
+//   the root specified with NewHttpZipFS (even if the paths start with a '/').
+
+// 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 {
+	path          string // absolute path within zip FS without leading '/'
+	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) {
+	var list []os.FileInfo
+	dirname := f.path + "/"
+	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) 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(name string) (http.File, os.Error) {
+	// fs.root does not start with '/'.
+	path := path.Join(fs.root, name) // path is clean
+	index, exact := fs.list.lookup(path)
+	if index < 0 || !strings.HasPrefix(path, fs.root) {
+		// file not found or not under root
+		return nil, fmt.Errorf("file not found: %s", name)
+	}
+
+	if exact {
+		// exact match found - must be a file
+		f := fs.list[index]
+		rc, err := f.Open()
+		if err != nil {
+			return nil, err
+		}
+		return &httpZipFile{
+			path,
+			os.FileInfo{
+				Name:     name,
+				Mode:     S_IFREG,
+				Size:     int64(f.UncompressedSize),
+				Mtime_ns: f.Mtime_ns(),
+			},
+			rc,
+			nil,
+		}, nil
+	}
+
+	// not an exact match - must be a directory
+	return &httpZipFile{
+		path,
+		os.FileInfo{
+			Name: name,
+			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()
+}
+
+// NewHttpZipFS creates a new http.FileSystem based on the contents of
+// the zip file rc restricted to the directory tree specified by root;
+// root must be an absolute path.
+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)}
+}