ref: d6ed17c60fd13c933347110c720afa09e04df1c8
dir: /hugofs/slice_fs.go/
// Copyright 2019 The Hugo Authors. All rights reserved.
//
// 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 hugofs
import (
"os"
"syscall"
"time"
"github.com/pkg/errors"
"github.com/spf13/afero"
)
var (
_ afero.Fs = (*SliceFs)(nil)
_ afero.Lstater = (*SliceFs)(nil)
_ afero.File = (*sliceDir)(nil)
)
func NewSliceFs(dirs ...FileMetaInfo) (afero.Fs, error) {
if len(dirs) == 0 {
return NoOpFs, nil
}
for _, dir := range dirs {
if !dir.IsDir() {
return nil, errors.New("this fs supports directories only")
}
}
fs := &SliceFs{
dirs: dirs,
}
return fs, nil
}
// SliceFs is an ordered composite filesystem.
type SliceFs struct {
dirs []FileMetaInfo
}
func (fs *SliceFs) Chmod(n string, m os.FileMode) error {
return syscall.EPERM
}
func (fs *SliceFs) Chtimes(n string, a, m time.Time) error {
return syscall.EPERM
}
func (fs *SliceFs) LstatIfPossible(name string) (os.FileInfo, bool, error) {
fi, _, err := fs.pickFirst(name)
if err != nil {
return nil, false, err
}
if fi.IsDir() {
return decorateFileInfo(fi, fs, fs.getOpener(name), "", "", nil), false, nil
}
return nil, false, errors.Errorf("lstat: files not supported: %q", name)
}
func (fs *SliceFs) Mkdir(n string, p os.FileMode) error {
return syscall.EPERM
}
func (fs *SliceFs) MkdirAll(n string, p os.FileMode) error {
return syscall.EPERM
}
func (fs *SliceFs) Name() string {
return "SliceFs"
}
func (fs *SliceFs) Open(name string) (afero.File, error) {
fi, idx, err := fs.pickFirst(name)
if err != nil {
return nil, err
}
if !fi.IsDir() {
panic("currently only dirs in here")
}
return &sliceDir{
lfs: fs,
idx: idx,
dirname: name,
}, nil
}
func (fs *SliceFs) OpenFile(name string, flag int, perm os.FileMode) (afero.File, error) {
panic("not implemented")
}
func (fs *SliceFs) ReadDir(name string) ([]os.FileInfo, error) {
panic("not implemented")
}
func (fs *SliceFs) Remove(n string) error {
return syscall.EPERM
}
func (fs *SliceFs) RemoveAll(p string) error {
return syscall.EPERM
}
func (fs *SliceFs) Rename(o, n string) error {
return syscall.EPERM
}
func (fs *SliceFs) Stat(name string) (os.FileInfo, error) {
fi, _, err := fs.LstatIfPossible(name)
return fi, err
}
func (fs *SliceFs) Create(n string) (afero.File, error) {
return nil, syscall.EPERM
}
func (fs *SliceFs) getOpener(name string) func() (afero.File, error) {
return func() (afero.File, error) {
return fs.Open(name)
}
}
func (fs *SliceFs) pickFirst(name string) (os.FileInfo, int, error) {
for i, mfs := range fs.dirs {
meta := mfs.Meta()
fs := meta.Fs()
fi, _, err := lstatIfPossible(fs, name)
if err == nil {
// Gotta match!
return fi, i, nil
}
if !os.IsNotExist(err) {
// Real error
return nil, -1, err
}
}
// Not found
return nil, -1, os.ErrNotExist
}
func (fs *SliceFs) readDirs(name string, startIdx, count int) ([]os.FileInfo, error) {
collect := func(lfs FileMeta) ([]os.FileInfo, error) {
d, err := lfs.Fs().Open(name)
if err != nil {
if !os.IsNotExist(err) {
return nil, err
}
return nil, nil
} else {
defer d.Close()
dirs, err := d.Readdir(-1)
if err != nil {
return nil, err
}
return dirs, nil
}
}
var dirs []os.FileInfo
for i := startIdx; i < len(fs.dirs); i++ {
mfs := fs.dirs[i]
fis, err := collect(mfs.Meta())
if err != nil {
return nil, err
}
dirs = append(dirs, fis...)
}
seen := make(map[string]bool)
var duplicates []int
for i, fi := range dirs {
if !fi.IsDir() {
continue
}
if seen[fi.Name()] {
duplicates = append(duplicates, i)
} else {
// Make sure it's opened by this filesystem.
dirs[i] = decorateFileInfo(fi, fs, fs.getOpener(fi.(FileMetaInfo).Meta().Filename()), "", "", nil)
seen[fi.Name()] = true
}
}
// Remove duplicate directories, keep first.
if len(duplicates) > 0 {
for i := len(duplicates) - 1; i >= 0; i-- {
idx := duplicates[i]
dirs = append(dirs[:idx], dirs[idx+1:]...)
}
}
if count > 0 && len(dirs) >= count {
return dirs[:count], nil
}
return dirs, nil
}
type sliceDir struct {
lfs *SliceFs
idx int
dirname string
}
func (f *sliceDir) Close() error {
return nil
}
func (f *sliceDir) Name() string {
return f.dirname
}
func (f *sliceDir) Read(p []byte) (n int, err error) {
panic("not implemented")
}
func (f *sliceDir) ReadAt(p []byte, off int64) (n int, err error) {
panic("not implemented")
}
func (f *sliceDir) Readdir(count int) ([]os.FileInfo, error) {
return f.lfs.readDirs(f.dirname, f.idx, count)
}
func (f *sliceDir) Readdirnames(count int) ([]string, error) {
dirsi, err := f.Readdir(count)
if err != nil {
return nil, err
}
dirs := make([]string, len(dirsi))
for i, d := range dirsi {
dirs[i] = d.Name()
}
return dirs, nil
}
func (f *sliceDir) Seek(offset int64, whence int) (int64, error) {
panic("not implemented")
}
func (f *sliceDir) Stat() (os.FileInfo, error) {
panic("not implemented")
}
func (f *sliceDir) Sync() error {
panic("not implemented")
}
func (f *sliceDir) Truncate(size int64) error {
panic("not implemented")
}
func (f *sliceDir) Write(p []byte) (n int, err error) {
panic("not implemented")
}
func (f *sliceDir) WriteAt(p []byte, off int64) (n int, err error) {
panic("not implemented")
}
func (f *sliceDir) WriteString(s string) (ret int, err error) {
panic("not implemented")
}