Add zipfs, an archive/zip-based read-only filesystem

README.md

@@ -380,7 +380,6 @@ The following is a short list of possible backends we hope someone will
 implement:
 
 * SSH
-* ZIP
 * TAR
 * S3
 

zipfs/file.go

@@ -0,0 +1,157 @@
+package zipfs
+
+import (
+	"archive/zip"
+	"io"
+	"os"
+	"path/filepath"
+	"syscall"
+
+	"github.com/spf13/afero"
+)
+
+type File struct {
+	fs            *Fs
+	zipfile       *zip.File
+	reader        io.ReadCloser
+	offset        int64
+	isdir, closed bool
+	buf           []byte
+}
+
+func (f *File) fillBuffer(offset int64) (err error) {
+	if f.reader == nil {
+		if f.reader, err = f.zipfile.Open(); err != nil {
+			return
+		}
+	}
+	if offset > int64(f.zipfile.UncompressedSize64) {
+		offset = int64(f.zipfile.UncompressedSize64)
+		err = io.EOF
+	}
+	if len(f.buf) >= int(offset) {
+		return
+	}
+	buf := make([]byte, int(offset)-len(f.buf))
+	n, _ := io.ReadFull(f.reader, buf)
+	if n > 0 {
+		f.buf = append(f.buf, buf[:n]...)
+	}
+	return
+}
+
+func (f *File) Close() (err error) {
+	f.zipfile = nil
+	f.closed = true
+	f.buf = nil
+	if f.reader != nil {
+		err = f.reader.Close()
+		f.reader = nil
+	}
+	return
+}
+
+func (f *File) Read(p []byte) (n int, err error) {
+	if f.isdir {
+		return 0, syscall.EISDIR
+	}
+	if f.closed {
+		return 0, afero.ErrFileClosed
+	}
+	err = f.fillBuffer(f.offset + int64(len(p)))
+	n = copy(p, f.buf[f.offset:])
+	f.offset += int64(len(p))
+	return
+}
+
+func (f *File) ReadAt(p []byte, off int64) (n int, err error) {
+	if f.isdir {
+		return 0, syscall.EISDIR
+	}
+	if f.closed {
+		return 0, afero.ErrFileClosed
+	}
+	err = f.fillBuffer(off + int64(len(p)))
+	n = copy(p, f.buf[int(off):])
+	return
+}
+
+func (f *File) Seek(offset int64, whence int) (int64, error) {
+	if f.isdir {
+		return 0, syscall.EISDIR
+	}
+	if f.closed {
+		return 0, afero.ErrFileClosed
+	}
+	switch whence {
+	case os.SEEK_SET:
+	case os.SEEK_CUR:
+		offset += f.offset
+	case os.SEEK_END:
+		offset += int64(f.zipfile.UncompressedSize64)
+	default:
+		return 0, syscall.EINVAL
+	}
+	if offset < 0 || offset > int64(f.zipfile.UncompressedSize64) {
+		return 0, afero.ErrOutOfRange
+	}
+	f.offset = offset
+	return offset, nil
+}
+
+func (f *File) Write(p []byte) (n int, err error) { return 0, syscall.EPERM }
+
+func (f *File) WriteAt(p []byte, off int64) (n int, err error) { return 0, syscall.EPERM }
+
+func (f *File) Name() string { return f.zipfile.Name }
+
+func (f *File) getDirEntries() (map[string]*zip.File, error) {
+	if !f.isdir {
+		return nil, syscall.ENOTDIR
+	}
+	name := string(filepath.Separator)
+	if f.zipfile != nil {
+		name = filepath.Join(splitpath(f.zipfile.Name))
+	}
+	entries, ok := f.fs.files[name]
+	if !ok {
+		return nil, &os.PathError{Op: "readdir", Path: name, Err: syscall.ENOENT}
+	}
+	return entries, nil
+}
+
+func (f *File) Readdir(count int) (fi []os.FileInfo, err error) {
+	zipfiles, err := f.getDirEntries()
+	if err != nil {
+		return nil, err
+	}
+	for _, zipfile := range zipfiles {
+		fi = append(fi, zipfile.FileInfo())
+		if count >= 0 && len(fi) >= count {
+			break
+		}
+	}
+	return
+}
+
+func (f *File) Readdirnames(count int) (names []string, err error) {
+	zipfiles, err := f.getDirEntries()
+	if err != nil {
+		return nil, err
+	}
+	for filename, _ := range zipfiles {
+		names = append(names, filename)
+		if count >= 0 && len(names) >= count {
+			break
+		}
+	}
+	return
+}
+
+func (f *File) Stat() (os.FileInfo, error) { return f.zipfile.FileInfo(), nil }
+
+func (f *File) Sync() error { return nil }
+
+func (f *File) Truncate(size int64) error { return syscall.EPERM }
+
+func (f *File) WriteString(s string) (ret int, err error) { return 0, syscall.EPERM }

zipfs/fs.go

@@ -0,0 +1,111 @@
+package zipfs
+
+import (
+	"archive/zip"
+	"os"
+	"path/filepath"
+	"syscall"
+	"time"
+
+	"github.com/spf13/afero"
+)
+
+type Fs struct {
+	r     *zip.Reader
+	files map[string]map[string]*zip.File
+}
+
+func splitpath(name string) (dir, file string) {
+	name = filepath.ToSlash(name)
+	if len(name) == 0 || name[0] != '/' {
+		name = "/" + name
+	}
+	name = filepath.Clean(name)
+	dir, file = filepath.Split(name)
+	dir = filepath.Clean(dir)
+	return
+}
+
+func New(r *zip.Reader) afero.Fs {
+	fs := &Fs{r: r, files: make(map[string]map[string]*zip.File)}
+	for _, file := range r.File {
+		d, f := splitpath(file.Name)
+		if _, ok := fs.files[d]; !ok {
+			fs.files[d] = make(map[string]*zip.File)
+		}
+		if _, ok := fs.files[d][f]; !ok {
+			fs.files[d][f] = file
+		}
+		if file.FileInfo().IsDir() {
+			dirname := filepath.Join(d, f)
+			if _, ok := fs.files[dirname]; !ok {
+				fs.files[dirname] = make(map[string]*zip.File)
+			}
+		}
+	}
+	return fs
+}
+
+func (fs *Fs) Create(name string) (afero.File, error) { return nil, syscall.EPERM }
+
+func (fs *Fs) Mkdir(name string, perm os.FileMode) error { return syscall.EPERM }
+
+func (fs *Fs) MkdirAll(path string, perm os.FileMode) error { return syscall.EPERM }
+
+func (fs *Fs) Open(name string) (afero.File, error) {
+	d, f := splitpath(name)
+	if f == "" {
+		return &File{fs: fs, isdir: true}, nil
+	}
+	if _, ok := fs.files[d]; !ok {
+		return nil, &os.PathError{Op: "stat", Path: name, Err: syscall.ENOENT}
+	}
+	file, ok := fs.files[d][f]
+	if !ok {
+		return nil, &os.PathError{Op: "stat", Path: name, Err: syscall.ENOENT}
+	}
+	return &File{fs: fs, zipfile: file, isdir: file.FileInfo().IsDir()}, nil
+}
+
+func (fs *Fs) OpenFile(name string, flag int, perm os.FileMode) (afero.File, error) {
+	if flag != os.O_RDONLY {
+		return nil, syscall.EPERM
+	}
+	return fs.Open(name)
+}
+
+func (fs *Fs) Remove(name string) error { return syscall.EPERM }
+
+func (fs *Fs) RemoveAll(path string) error { return syscall.EPERM }
+
+func (fs *Fs) Rename(oldname, newname string) error { return syscall.EPERM }
+
+type pseudoRoot struct{}
+
+func (p *pseudoRoot) Name() string       { return string(filepath.Separator) }
+func (p *pseudoRoot) Size() int64        { return 0 }
+func (p *pseudoRoot) Mode() os.FileMode  { return os.ModeDir | os.ModePerm }
+func (p *pseudoRoot) ModTime() time.Time { return time.Now() }
+func (p *pseudoRoot) IsDir() bool        { return true }
+func (p *pseudoRoot) Sys() interface{}   { return nil }
+
+func (fs *Fs) Stat(name string) (os.FileInfo, error) {
+	d, f := splitpath(name)
+	if f == "" {
+		return &pseudoRoot{}, nil
+	}
+	if _, ok := fs.files[d]; !ok {
+		return nil, &os.PathError{Op: "stat", Path: name, Err: syscall.ENOENT}
+	}
+	file, ok := fs.files[d][f]
+	if !ok {
+		return nil, &os.PathError{Op: "stat", Path: name, Err: syscall.ENOENT}
+	}
+	return file.FileInfo(), nil
+}
+
+func (fs *Fs) Name() string { return "zipfs" }
+
+func (fs *Fs) Chmod(name string, mode os.FileMode) error { return syscall.EPERM }
+
+func (fs *Fs) Chtimes(name string, atime time.Time, mtime time.Time) error { return syscall.EPERM }

zipfs/zipfs_test.go

@@ -0,0 +1,88 @@
+package zipfs
+
+import (
+	"github.com/spf13/afero"
+
+	"archive/zip"
+	"path/filepath"
+	"reflect"
+	"testing"
+)
+
+func TestZipFS(t *testing.T) {
+	zrc, err := zip.OpenReader("testdata/t.zip")
+	if err != nil {
+		t.Fatal(err)
+	}
+	zfs := New(&zrc.Reader)
+	a := &afero.Afero{Fs: zfs}
+
+	buf, err := a.ReadFile("testFile")
+	if err != nil {
+		t.Error(err)
+	}
+	if len(buf) != 8192 {
+		t.Errorf("short read: %d != 8192", len(buf))
+	}
+
+	buf = make([]byte, 8)
+	f, err := a.Open("testFile")
+	if err != nil {
+		t.Error(err)
+	}
+	if n, err := f.ReadAt(buf, 4092); err != nil {
+		t.Error(err)
+	} else if n != 8 {
+		t.Errorf("expected to read 8 bytes, got %d", n)
+	} else if string(buf) != "aaaabbbb" {
+		t.Errorf("expected to get <aaaabbbb>, got <%s>", string(buf))
+	}
+
+	buf = make([]byte, 8192)
+	if n, err := f.Read(buf); err != nil {
+		t.Error(err)
+	} else if n != 8192 {
+		t.Errorf("expected to read 8192 bytes, got %d", n)
+	} else if buf[4095] != 'a' || buf[4096] != 'b' {
+		t.Error("got wrong contents")
+	}
+
+	for _, s := range []struct {
+		path string
+		dir  bool
+	}{
+		{"testDir1", true},
+		{"testDir1/testFile", false},
+		{"testFile", false},
+		{"sub", true},
+		{"sub/testDir2", true},
+		{"sub/testDir2/testFile", false},
+	} {
+		if dir, _ := a.IsDir(s.path); dir == s.dir {
+			t.Logf("%s: directory check ok", s.path)
+		} else {
+			t.Errorf("%s: directory check NOT ok: %t, expected %t", s.path, dir, s.dir)
+		}
+	}
+
+	for _, s := range []struct {
+		glob    string
+		entries []string
+	}{
+		{filepath.FromSlash("/*"), []string{filepath.FromSlash("/sub"), filepath.FromSlash("/testDir1"), filepath.FromSlash("/testFile")}},
+		{filepath.FromSlash("*"), []string{filepath.FromSlash("sub"), filepath.FromSlash("testDir1"), filepath.FromSlash("testFile")}},
+		{filepath.FromSlash("sub/*"), []string{filepath.FromSlash("sub/testDir2")}},
+		{filepath.FromSlash("sub/testDir2/*"), []string{filepath.FromSlash("sub/testDir2/testFile")}},
+		{filepath.FromSlash("testDir1/*"), []string{filepath.FromSlash("testDir1/testFile")}},
+	} {
+		entries, err := afero.Glob(zfs, s.glob)
+		if err != nil {
+			t.Error(err)
+		}
+		if reflect.DeepEqual(entries, s.entries) {
+			t.Logf("glob: %s: glob ok", s.glob)
+		} else {
+			t.Errorf("glob: %s: got %#v, expected %#v", s.glob, entries, s.entries)
+		}
+	}
+}