ref: 173187e2633f3fc037c83e1e3de2902ae3c93b92
dir: /hugofs/walk.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 (
"fmt"
"os"
"path/filepath"
"sort"
"strings"
"github.com/gohugoio/hugo/common/loggers"
"github.com/pkg/errors"
"github.com/spf13/afero"
)
type (
WalkFunc func(path string, info FileMetaInfo, err error) error
WalkHook func(dir FileMetaInfo, path string, readdir []FileMetaInfo) ([]FileMetaInfo, error)
)
type Walkway struct {
fs afero.Fs
root string
basePath string
logger loggers.Logger
// May be pre-set
fi FileMetaInfo
dirEntries []FileMetaInfo
walkFn WalkFunc
walked bool
// We may traverse symbolic links and bite ourself.
seen map[string]bool
// Optional hooks
hookPre WalkHook
hookPost WalkHook
}
type WalkwayConfig struct {
Fs afero.Fs
Root string
BasePath string
Logger loggers.Logger
// One or both of these may be pre-set.
Info FileMetaInfo
DirEntries []FileMetaInfo
WalkFn WalkFunc
HookPre WalkHook
HookPost WalkHook
}
func NewWalkway(cfg WalkwayConfig) *Walkway {
var fs afero.Fs
if cfg.Info != nil {
fs = cfg.Info.Meta().Fs()
} else {
fs = cfg.Fs
}
basePath := cfg.BasePath
if basePath != "" && !strings.HasSuffix(basePath, filepathSeparator) {
basePath += filepathSeparator
}
logger := cfg.Logger
if logger == nil {
logger = loggers.NewWarningLogger()
}
return &Walkway{
fs: fs,
root: cfg.Root,
basePath: basePath,
fi: cfg.Info,
dirEntries: cfg.DirEntries,
walkFn: cfg.WalkFn,
hookPre: cfg.HookPre,
hookPost: cfg.HookPost,
logger: logger,
seen: make(map[string]bool)}
}
func (w *Walkway) Walk() error {
if w.walked {
panic("this walkway is already walked")
}
w.walked = true
if w.fs == NoOpFs {
return nil
}
var fi FileMetaInfo
if w.fi != nil {
fi = w.fi
} else {
info, _, err := lstatIfPossible(w.fs, w.root)
if err != nil {
if os.IsNotExist(err) {
return nil
}
if w.checkErr(w.root, err) {
return nil
}
return w.walkFn(w.root, nil, errors.Wrapf(err, "walk: %q", w.root))
}
fi = info.(FileMetaInfo)
}
if !fi.IsDir() {
return w.walkFn(w.root, nil, errors.New("file to walk must be a directory"))
}
return w.walk(w.root, fi, w.dirEntries, w.walkFn)
}
// if the filesystem supports it, use Lstat, else use fs.Stat
func lstatIfPossible(fs afero.Fs, path string) (os.FileInfo, bool, error) {
if lfs, ok := fs.(afero.Lstater); ok {
fi, b, err := lfs.LstatIfPossible(path)
return fi, b, err
}
fi, err := fs.Stat(path)
return fi, false, err
}
// checkErr returns true if the error is handled.
func (w *Walkway) checkErr(filename string, err error) bool {
if err == ErrPermissionSymlink {
logUnsupportedSymlink(filename, w.logger)
return true
}
if os.IsNotExist(err) {
// The file may be removed in process.
// This may be a ERROR situation, but it is not possible
// to determine as a general case.
w.logger.Warnf("File %q not found, skipping.", filename)
return true
}
return false
}
func logUnsupportedSymlink(filename string, logger loggers.Logger) {
logger.Warnf("Unsupported symlink found in %q, skipping.", filename)
}
// walk recursively descends path, calling walkFn.
// It follow symlinks if supported by the filesystem, but only the same path once.
func (w *Walkway) walk(path string, info FileMetaInfo, dirEntries []FileMetaInfo, walkFn WalkFunc) error {
err := walkFn(path, info, nil)
if err != nil {
if info.IsDir() && err == filepath.SkipDir {
return nil
}
return err
}
if !info.IsDir() {
return nil
}
meta := info.Meta()
filename := meta.Filename()
if dirEntries == nil {
f, err := w.fs.Open(path)
if err != nil {
if w.checkErr(path, err) {
return nil
}
return walkFn(path, info, errors.Wrapf(err, "walk: open %q (%q)", path, w.root))
}
fis, err := f.Readdir(-1)
f.Close()
if err != nil {
if w.checkErr(filename, err) {
return nil
}
return walkFn(path, info, errors.Wrap(err, "walk: Readdir"))
}
dirEntries = fileInfosToFileMetaInfos(fis)
if !meta.IsOrdered() {
sort.Slice(dirEntries, func(i, j int) bool {
fii := dirEntries[i]
fij := dirEntries[j]
fim, fjm := fii.Meta(), fij.Meta()
// Pull bundle headers to the top.
ficlass, fjclass := fim.Classifier(), fjm.Classifier()
if ficlass != fjclass {
return ficlass < fjclass
}
// With multiple content dirs with different languages,
// there can be duplicate files, and a weight will be added
// to the closest one.
fiw, fjw := fim.Weight(), fjm.Weight()
if fiw != fjw {
return fiw > fjw
}
// Explicit order set.
fio, fjo := fim.Ordinal(), fjm.Ordinal()
if fio != fjo {
return fio < fjo
}
// When we walk into a symlink, we keep the reference to
// the original name.
fin, fjn := fim.Name(), fjm.Name()
if fin != "" && fjn != "" {
return fin < fjn
}
return fii.Name() < fij.Name()
})
}
}
// First add some metadata to the dir entries
for _, fi := range dirEntries {
fim := fi.(FileMetaInfo)
meta := fim.Meta()
// Note that we use the original Name even if it's a symlink.
name := meta.Name()
if name == "" {
name = fim.Name()
}
if name == "" {
panic(fmt.Sprintf("[%s] no name set in %v", path, meta))
}
pathn := filepath.Join(path, name)
pathMeta := pathn
if w.basePath != "" {
pathMeta = strings.TrimPrefix(pathn, w.basePath)
}
meta[metaKeyPath] = normalizeFilename(pathMeta)
meta[metaKeyPathWalk] = pathn
if fim.IsDir() && w.isSeen(meta.Filename()) {
// Prevent infinite recursion
// Possible cyclic reference
meta[metaKeySkipDir] = true
}
}
if w.hookPre != nil {
dirEntries, err = w.hookPre(info, path, dirEntries)
if err != nil {
if err == filepath.SkipDir {
return nil
}
return err
}
}
for _, fi := range dirEntries {
fim := fi.(FileMetaInfo)
meta := fim.Meta()
if meta.SkipDir() {
continue
}
err := w.walk(meta.GetString(metaKeyPathWalk), fim, nil, walkFn)
if err != nil {
if !fi.IsDir() || err != filepath.SkipDir {
return err
}
}
}
if w.hookPost != nil {
dirEntries, err = w.hookPost(info, path, dirEntries)
if err != nil {
if err == filepath.SkipDir {
return nil
}
return err
}
}
return nil
}
func (w *Walkway) isSeen(filename string) bool {
if filename == "" {
return false
}
if w.seen[filename] {
return true
}
w.seen[filename] = true
return false
}