support for io/fs

Author: mandelsoft

README.md

@@ -77,8 +77,13 @@ for example a `cwdfs.WorkingDirectoryFileSystem` or a
 The package `osfs` supports creating a temporary os filesystem based
 virtual filesystem residing in a temporary operating system directory.
 
-Additional the interface `VFS` includes the standard filesystem operations
+Additionally, the interface `VFS` includes the standard filesystem operations
 and some implementation independent utility functions based on a virtual
 filesystem known from the `os`, `ìoutil` and `filepath` packages.
 The function `vfs.New(fs)` can be used to create such a wrapper for
-any virtual filesystem.
+any virtual filesystem.
+
+A virtual filesystem can be used as `io/fs.FS` or `io/fs.ReadDirFS`.
+Because of the Go typesystem and the stripped interface `io/fs.File`,
+this is not directly possible. But any virtual filesystem can be converted
+by a type converting wrapper function `vfs.AsIoFS(fs)`.

go.sum

@@ -26,7 +26,6 @@ github.com/onsi/gomega v1.10.1 h1:o0+MgICZLuZ7xjH7Vx6zS/zcu93/BEp1VwkIW1mEXCE=
 github.com/onsi/gomega v1.10.1/go.mod h1:iN09h71vgCQne3DLsj+A5owkum+a2tYe+TOCB1ybHNo=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/net v0.0.0-20180906233101-161cd47e91fd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
-golang.org/x/net v0.0.0-20200520004742-59133d7f0dd7 h1:AeiKBIuRw3UomYXSbLy0Mc2dDLfdtbT/IVn4keq83P0=
 golang.org/x/net v0.0.0-20200520004742-59133d7f0dd7/go.mod h1:qpuaurCH72eLCgpAm/N6yyVIVM9cpaDIP3A8BGJEC5A=
 golang.org/x/net v0.11.0 h1:Gi2tvZIJyBtO9SDr1q9h5hEQCp/4L2RQ+ar0qjx2oNU=
 golang.org/x/net v0.11.0/go.mod h1:2L/ixqYpgIVXmeoSA/4Lu7BzTG4KIyPIryS4IsOd1oQ=
@@ -37,17 +36,14 @@ golang.org/x/sys v0.0.0-20190904154756-749cb33beabd/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20191005200804-aed5e4c7ecf9/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20191120155948-bd437916bb0e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20200519105757-fe76b779f299 h1:DYfZAGf2WMFjMxbgTjaC+2HC7NkNAQs+6Q8b9WEB/F4=
 golang.org/x/sys v0.0.0-20200519105757-fe76b779f299/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.9.0 h1:KS/R3tvhPqvJvwcKfnBHJwwthS11LRhmM5D59eEXa0s=
 golang.org/x/sys v0.9.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
-golang.org/x/text v0.3.2 h1:tW2bmiBqwgJj/UpqtC8EpXEZVYOwU0yG4iWbprSVAcs=
 golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
 golang.org/x/text v0.10.0 h1:UpjohKhiEgNc0CSauXmwYftY1+LlaC75SJwh0SgCX58=
 golang.org/x/text v0.10.0/go.mod h1:TvPlkZtksWOMsz7fbANvkp4WM8x/WCo/om8BMLbz+aE=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
-golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20220907171357-04be3eba64a2 h1:H2TDz8ibqkAF6YGhCdN3jS9O0/s90v0rJh3X/OLHEUk=
 golang.org/x/xerrors v0.0.0-20220907171357-04be3eba64a2/go.mod h1:K8+ghG5WaK9qNqU5K3HdILfMLy1f3aNYFI/wnl100a8=

pkg/utils/file.go

@@ -22,6 +22,7 @@ import (
 	"bytes"
 	"errors"
 	"io"
+	"io/fs"
 	"os"
 	"sort"
 	"time"
@@ -86,6 +87,19 @@ func (f *File) Sync() error {
 	return nil
 }
 
+func (f *File) ReadDir(count int) (files []fs.DirEntry, err error) {
+	o, err := f.Readdir(count)
+
+	if err != nil {
+		return nil, err
+	}
+	r := make([]fs.DirEntry, len(o), len(o))
+	for i, v := range o {
+		r[i] = fs.FileInfoToDirEntry(v)
+	}
+	return r, nil
+}
+
 func (f *File) Readdir(count int) (files []os.FileInfo, err error) {
 	if !f.fileData.IsDir() {
 		return nil, &os.PathError{Op: "readdir", Path: f.name, Err: ErrNotDir}

pkg/vfs/interface.go

@@ -20,6 +20,7 @@ package vfs
 
 import (
 	"io"
+	"io/fs"
 	"os"
 	"time"
 )
@@ -29,6 +30,7 @@ const PathSeparatorString = "/"
 
 type FileMode = os.FileMode
 type FileInfo = os.FileInfo
+type DirEntry = fs.DirEntry
 
 const ModePerm = os.ModePerm
 
@@ -77,17 +79,17 @@ type FileSystem interface {
 
 	// Mkdir creates a directory in the filesystem, return an error if any
 	// happens.
-	Mkdir(name string, perm os.FileMode) error
+	Mkdir(name string, perm FileMode) error
 
 	// MkdirAll creates a directory path and all parents that does not exist
 	// yet.
-	MkdirAll(path string, perm os.FileMode) error
+	MkdirAll(path string, perm FileMode) error
 
 	// Open opens a file, returning it or an error, if any happens.
 	Open(name string) (File, error)
 
 	// OpenFile opens a file using the given flags and the given mode.
-	OpenFile(name string, flags int, perm os.FileMode) (File, error)
+	OpenFile(name string, flags int, perm FileMode) (File, error)
 
 	// Remove removes a file identified by name, returning an error, if any
 	// happens.
@@ -102,13 +104,13 @@ type FileSystem interface {
 
 	// Stat returns a FileInfo describing the named file, or an error, if any
 	// happens.
-	Stat(name string) (os.FileInfo, error)
+	Stat(name string) (FileInfo, error)
 
 	// Lstat returns a FileInfo describing the named file, or an error, if any
 	// happens.
 	// If the file is a symbolic link, the returned FileInfo
 	// describes the symbolic link. Lstat makes no attempt to follow the link.
-	Lstat(name string) (os.FileInfo, error)
+	Lstat(name string) (FileInfo, error)
 
 	// Create a symlink if supported
 	Symlink(oldname, newname string) error
@@ -120,7 +122,7 @@ type FileSystem interface {
 	Name() string
 
 	// Chmod changes the mode of the named file to mode.
-	Chmod(name string, mode os.FileMode) error
+	Chmod(name string, mode FileMode) error
 
 	// Chtimes changes the access and modification times of the named file
 	Chtimes(name string, atime time.Time, mtime time.Time) error
@@ -152,9 +154,10 @@ type File interface {
 	io.WriterAt
 
 	Name() string
-	Readdir(count int) ([]os.FileInfo, error)
+	ReadDir(count int) ([]DirEntry, error)
+	Readdir(count int) ([]FileInfo, error)
 	Readdirnames(n int) ([]string, error)
-	Stat() (os.FileInfo, error)
+	Stat() (FileInfo, error)
 	Sync() error
 	Truncate(size int64) error
 	WriteString(s string) (ret int, err error)
@@ -189,9 +192,9 @@ type VFS interface {
 	IsDir(path string) (bool, error)
 	IsFile(path string) (bool, error)
 
-	ReadDir(path string) ([]os.FileInfo, error)
+	ReadDir(path string) ([]FileInfo, error)
 	ReadFile(path string) ([]byte, error)
-	WriteFile(path string, data []byte, mode os.FileMode) error
+	WriteFile(path string, data []byte, mode FileMode) error
 	TempFile(dir, prefix string) (File, error)
 	TempDir(dir, prefix string) (string, error)
 }

pkg/vfs/iofs.go

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2023 Mandelsoft. All rights reserved.
+ *  This file is licensed under the Apache Software License, v. 2 except as noted
+ *  otherwise in the LICENSE file
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+package vfs
+
+import (
+	"io/fs"
+	"sort"
+)
+
+type iofs struct {
+	FileSystem
+}
+
+var (
+	_ fs.File        = File(nil)
+	_ fs.ReadDirFile = File(nil)
+)
+
+func (i *iofs) Open(name string) (fs.File, error) {
+	return i.FileSystem.Open(name)
+}
+
+func (i *iofs) ReadDir(name string) ([]fs.DirEntry, error) {
+	f, err := i.FileSystem.Open(name)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	dirs, err := f.ReadDir(-1)
+	sort.Slice(dirs, func(i, j int) bool { return dirs[i].Name() < dirs[j].Name() })
+	return dirs, err
+}
+
+// AsIoFS maps a virtual filesystem
+func AsIoFS(fs FileSystem) fs.ReadDirFS {
+	return &iofs{fs}
+}