hugo/hugofs/language_composite_fs.go

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// Copyright 2018 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"
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"github.com/spf13/afero"
)
var (
_ afero.Fs = (*languageCompositeFs)(nil)
_ afero.Lstater = (*languageCompositeFs)(nil)
_ FilesystemsUnwrapper = (*languageCompositeFs)(nil)
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)
type languageCompositeFs struct {
base afero.Fs
overlay afero.Fs
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*afero.CopyOnWriteFs
}
// NewLanguageCompositeFs creates a composite and language aware filesystem.
// This is a hybrid filesystem. To get a specific file in Open, Stat etc., use the full filename
// to the target filesystem. This information is available in Readdir, Stat etc. via the
// special LanguageFileInfo FileInfo implementation.
func NewLanguageCompositeFs(base, overlay afero.Fs) afero.Fs {
return &languageCompositeFs{base, overlay, afero.NewCopyOnWriteFs(base, overlay).(*afero.CopyOnWriteFs)}
}
func (fs *languageCompositeFs) UnwrapFilesystems() []afero.Fs {
return []afero.Fs{fs.base, fs.overlay}
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}
// Open takes the full path to the file in the target filesystem. If it is a directory, it gets merged
// using the language as a weight.
func (fs *languageCompositeFs) Open(name string) (afero.File, error) {
f, err := fs.CopyOnWriteFs.Open(name)
if err != nil {
return nil, err
}
fu, ok := f.(*afero.UnionFile)
if ok {
// This is a directory: Merge it.
fu.Merger = LanguageDirsMerger
}
return f, nil
}
// LanguageDirsMerger implements the afero.DirsMerger interface, which is used
// to merge two directories.
var LanguageDirsMerger = func(lofi, bofi []os.FileInfo) ([]os.FileInfo, error) {
for _, fi1 := range bofi {
fim1 := fi1.(FileMetaInfo)
var found bool
for _, fi2 := range lofi {
fim2 := fi2.(FileMetaInfo)
if fi1.Name() == fi2.Name() && fim1.Meta().Lang == fim2.Meta().Lang {
found = true
break
}
}
if !found {
lofi = append(lofi, fi1)
}
}
return lofi, nil
}