ref: 6b59b64f02341c67a3606d2bbb3b9934d6276a74
dir: /hugofs/rootmapping_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 (
"fmt"
"os"
"path/filepath"
"strings"
"github.com/gohugoio/hugo/hugofs/files"
"github.com/pkg/errors"
radix "github.com/armon/go-radix"
"github.com/spf13/afero"
)
var filepathSeparator = string(filepath.Separator)
// NewRootMappingFs creates a new RootMappingFs on top of the provided with
// of root mappings with some optional metadata about the root.
// Note that From represents a virtual root that maps to the actual filename in To.
func NewRootMappingFs(fs afero.Fs, rms ...RootMapping) (*RootMappingFs, error) {
rootMapToReal := radix.New()
for _, rm := range rms {
(&rm).clean()
fromBase := files.ResolveComponentFolder(rm.From)
if fromBase == "" {
panic("unrecognised component folder in" + rm.From)
}
if len(rm.To) < 2 {
panic(fmt.Sprintf("invalid root mapping; from/to: %s/%s", rm.From, rm.To))
}
_, err := fs.Stat(rm.To)
if err != nil {
if os.IsNotExist(err) {
continue
}
return nil, err
}
// Extract "blog" from "content/blog"
rm.path = strings.TrimPrefix(strings.TrimPrefix(rm.From, fromBase), filepathSeparator)
key := rm.rootKey()
var mappings []RootMapping
v, found := rootMapToReal.Get(key)
if found {
// There may be more than one language pointing to the same root.
mappings = v.([]RootMapping)
}
mappings = append(mappings, rm)
rootMapToReal.Insert(key, mappings)
}
rfs := &RootMappingFs{Fs: fs,
virtualRoots: rms,
rootMapToReal: rootMapToReal}
return rfs, nil
}
// NewRootMappingFsFromFromTo is a convenicence variant of NewRootMappingFs taking
// From and To as string pairs.
func NewRootMappingFsFromFromTo(fs afero.Fs, fromTo ...string) (*RootMappingFs, error) {
rms := make([]RootMapping, len(fromTo)/2)
for i, j := 0, 0; j < len(fromTo); i, j = i+1, j+2 {
rms[i] = RootMapping{
From: fromTo[j],
To: fromTo[j+1],
}
}
return NewRootMappingFs(fs, rms...)
}
type RootMapping struct {
From string
To string
path string // The virtual mount point, e.g. "blog".
Meta FileMeta // File metadata (lang etc.)
}
func (rm *RootMapping) clean() {
rm.From = strings.Trim(filepath.Clean(rm.From), filepathSeparator)
rm.To = filepath.Clean(rm.To)
}
func (r RootMapping) filename(name string) string {
if name == "" {
return r.To
}
return filepath.Join(r.To, strings.TrimPrefix(name, r.From))
}
func (r RootMapping) rootKey() string {
return r.From
}
// A RootMappingFs maps several roots into one. Note that the root of this filesystem
// is directories only, and they will be returned in Readdir and Readdirnames
// in the order given.
type RootMappingFs struct {
afero.Fs
rootMapToReal *radix.Tree
virtualRoots []RootMapping
filter func(r RootMapping) bool
}
func (fs *RootMappingFs) Dirs(base string) ([]FileMetaInfo, error) {
roots := fs.getRootsWithPrefix(base)
if roots == nil {
return nil, nil
}
fss := make([]FileMetaInfo, len(roots))
for i, r := range roots {
bfs := afero.NewBasePathFs(fs.Fs, r.To)
bfs = decoratePath(bfs, func(name string) string {
p := strings.TrimPrefix(name, r.To)
if r.path != "" {
// Make sure it's mounted to a any sub path, e.g. blog
p = filepath.Join(r.path, p)
}
p = strings.TrimLeft(p, filepathSeparator)
return p
})
fs := decorateDirs(bfs, r.Meta)
fi, err := fs.Stat("")
if err != nil {
return nil, errors.Wrap(err, "RootMappingFs.Dirs")
}
fss[i] = fi.(FileMetaInfo)
}
return fss, nil
}
// LstatIfPossible returns the os.FileInfo structure describing a given file.
func (fs *RootMappingFs) LstatIfPossible(name string) (os.FileInfo, bool, error) {
fis, _, b, err := fs.doLstat(name, false)
if err != nil {
return nil, b, err
}
return fis[0], b, nil
}
func (fs *RootMappingFs) virtualDirOpener(name string, isRoot bool) func() (afero.File, error) {
return func() (afero.File, error) { return &rootMappingFile{name: name, isRoot: isRoot, fs: fs}, nil }
}
func (fs *RootMappingFs) doLstat(name string, allowMultiple bool) ([]FileMetaInfo, []FileMetaInfo, bool, error) {
if fs.isRoot(name) {
return []FileMetaInfo{newDirNameOnlyFileInfo(name, true, fs.virtualDirOpener(name, true))}, nil, false, nil
}
roots := fs.getRoots(name)
rootsWithPrefix := fs.getRootsWithPrefix(name)
hasRootMappingsBelow := len(rootsWithPrefix) != 0
if len(roots) == 0 {
if hasRootMappingsBelow {
// No exact matches, but we have root mappings below name,
// let's make it look like a directory.
return []FileMetaInfo{newDirNameOnlyFileInfo(name, true, fs.virtualDirOpener(name, false))}, nil, false, nil
}
return nil, nil, false, os.ErrNotExist
}
// We may have a mapping for both static and static/subdir.
// These will not show in any Readdir so append them
// manually.
rootsInDir := fs.filterRootsBelow(rootsWithPrefix, name)
var (
fis []FileMetaInfo
dirs []FileMetaInfo
b bool
root RootMapping
err error
)
for _, root = range roots {
var fi os.FileInfo
fi, b, err = fs.statRoot(root, name)
if err != nil {
if os.IsNotExist(err) {
continue
}
return nil, nil, false, err
}
fim := fi.(FileMetaInfo)
fis = append(fis, fim)
}
for _, root = range rootsInDir {
fi, _, err := fs.statRoot(root, "")
if err != nil {
if os.IsNotExist(err) {
continue
}
return nil, nil, false, err
}
fim := fi.(FileMetaInfo)
dirs = append(dirs, fim)
}
if len(fis) == 0 && len(dirs) == 0 {
return nil, nil, false, os.ErrNotExist
}
if allowMultiple || len(fis) == 1 {
return fis, dirs, b, nil
}
if len(fis) == 0 {
return nil, nil, false, os.ErrNotExist
}
// Open it in this composite filesystem.
opener := func() (afero.File, error) {
return fs.Open(name)
}
return []FileMetaInfo{decorateFileInfo(fis[0], fs, opener, "", "", root.Meta)}, nil, b, nil
}
// Open opens the namedrootMappingFile file for reading.
func (fs *RootMappingFs) Open(name string) (afero.File, error) {
if fs.isRoot(name) {
return &rootMappingFile{name: name, fs: fs, isRoot: true}, nil
}
fis, dirs, _, err := fs.doLstat(name, true)
if err != nil {
return nil, err
}
if len(fis) == 1 {
fi := fis[0]
meta := fi.(FileMetaInfo).Meta()
f, err := meta.Open()
if err != nil {
return nil, err
}
f = &rootMappingFile{File: f, fs: fs, name: name, meta: meta}
if len(dirs) > 0 {
return &readDirDirsAppender{File: f, dirs: dirs}, nil
}
return f, nil
}
f, err := fs.newUnionFile(fis...)
if err != nil {
return nil, err
}
if len(dirs) > 0 {
return &readDirDirsAppender{File: f, dirs: dirs}, nil
}
return f, nil
}
// Stat returns the os.FileInfo structure describing a given file. If there is
// an error, it will be of type *os.PathError.
func (fs *RootMappingFs) Stat(name string) (os.FileInfo, error) {
fi, _, err := fs.LstatIfPossible(name)
return fi, err
}
// Filter creates a copy of this filesystem with the applied filter.
func (fs RootMappingFs) Filter(f func(m RootMapping) bool) *RootMappingFs {
fs.filter = f
return &fs
}
func (fs *RootMappingFs) isRoot(name string) bool {
return name == "" || name == filepathSeparator
}
func (fs *RootMappingFs) getRoots(name string) []RootMapping {
name = filepath.Clean(name)
_, v, found := fs.rootMapToReal.LongestPrefix(name)
if !found {
return nil
}
rm := v.([]RootMapping)
return fs.applyFilterToRoots(rm)
}
func (fs *RootMappingFs) applyFilterToRoots(rm []RootMapping) []RootMapping {
if fs.filter == nil {
return rm
}
var filtered []RootMapping
for _, m := range rm {
if fs.filter(m) {
filtered = append(filtered, m)
}
}
return filtered
}
func (fs *RootMappingFs) getRootsWithPrefix(prefix string) []RootMapping {
if fs.isRoot(prefix) {
return fs.virtualRoots
}
prefix = filepath.Clean(prefix)
var roots []RootMapping
fs.rootMapToReal.WalkPrefix(prefix, func(b string, v interface{}) bool {
roots = append(roots, v.([]RootMapping)...)
return false
})
return fs.applyFilterToRoots(roots)
}
// Filter out the mappings inside the name directory.
func (fs *RootMappingFs) filterRootsBelow(roots []RootMapping, name string) []RootMapping {
if len(roots) == 0 {
return nil
}
sepCount := strings.Count(name, filepathSeparator)
var filtered []RootMapping
for _, x := range roots {
if name == x.From {
continue
}
if strings.Count(x.From, filepathSeparator)-sepCount != 1 {
continue
}
filtered = append(filtered, x)
}
return filtered
}
func (fs *RootMappingFs) newUnionFile(fis ...FileMetaInfo) (afero.File, error) {
meta := fis[0].Meta()
f, err := meta.Open()
if err != nil {
return nil, err
}
rf := &rootMappingFile{File: f, fs: fs, name: meta.Name(), meta: meta}
if len(fis) == 1 {
return rf, err
}
next, err := fs.newUnionFile(fis[1:]...)
if err != nil {
return nil, err
}
uf := &afero.UnionFile{Base: rf, Layer: next}
uf.Merger = func(lofi, bofi []os.FileInfo) ([]os.FileInfo, error) {
// Ignore duplicate directory entries
seen := make(map[string]bool)
var result []os.FileInfo
for _, fis := range [][]os.FileInfo{bofi, lofi} {
for _, fi := range fis {
if fi.IsDir() && seen[fi.Name()] {
continue
}
if fi.IsDir() {
seen[fi.Name()] = true
}
result = append(result, fi)
}
}
return result, nil
}
return uf, nil
}
func (fs *RootMappingFs) statRoot(root RootMapping, name string) (os.FileInfo, bool, error) {
filename := root.filename(name)
var b bool
var fi os.FileInfo
var err error
if ls, ok := fs.Fs.(afero.Lstater); ok {
fi, b, err = ls.LstatIfPossible(filename)
if err != nil {
return nil, b, err
}
} else {
fi, err = fs.Fs.Stat(filename)
if err != nil {
return nil, b, err
}
}
// Opens the real directory/file.
opener := func() (afero.File, error) {
return fs.Fs.Open(filename)
}
if fi.IsDir() {
if name == "" {
name = root.From
}
_, name = filepath.Split(name)
fi = newDirNameOnlyFileInfo(name, false, opener)
}
return decorateFileInfo(fi, fs.Fs, opener, "", "", root.Meta), b, nil
}
type rootMappingFile struct {
afero.File
fs *RootMappingFs
name string
meta FileMeta
isRoot bool
}
type readDirDirsAppender struct {
afero.File
dirs []FileMetaInfo
}
func (f *readDirDirsAppender) Readdir(count int) ([]os.FileInfo, error) {
fis, err := f.File.Readdir(count)
if err != nil {
return nil, err
}
for _, dir := range f.dirs {
fis = append(fis, dir)
}
return fis, nil
}
func (f *readDirDirsAppender) Readdirnames(count int) ([]string, error) {
fis, err := f.Readdir(count)
if err != nil {
return nil, err
}
return fileInfosToNames(fis), nil
}
func (f *rootMappingFile) Close() error {
if f.File == nil {
return nil
}
return f.File.Close()
}
func (f *rootMappingFile) Name() string {
return f.name
}
func (f *rootMappingFile) Readdir(count int) ([]os.FileInfo, error) {
if f.File == nil {
dirsn := make([]os.FileInfo, 0)
roots := f.fs.getRootsWithPrefix(f.name)
seen := make(map[string]bool)
j := 0
for _, rm := range roots {
if count != -1 && j >= count {
break
}
opener := func() (afero.File, error) {
return f.fs.Open(rm.From)
}
name := rm.From
if !f.isRoot {
_, name = filepath.Split(rm.From)
}
if seen[name] {
continue
}
seen[name] = true
j++
fi := newDirNameOnlyFileInfo(name, false, opener)
if rm.Meta != nil {
mergeFileMeta(rm.Meta, fi.Meta())
}
dirsn = append(dirsn, fi)
}
return dirsn, nil
}
if f.File == nil {
panic(fmt.Sprintf("no File for %q", f.name))
}
fis, err := f.File.Readdir(count)
if err != nil {
return nil, err
}
for i, fi := range fis {
fis[i] = decorateFileInfo(fi, f.fs, nil, "", "", f.meta)
}
return fis, nil
}
func (f *rootMappingFile) Readdirnames(count int) ([]string, error) {
dirs, err := f.Readdir(count)
if err != nil {
return nil, err
}
return fileInfosToNames(dirs), nil
}