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"
"path"
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"github.com/spf13/afero"
)
var (
_ afero.Fs = (*languageCompositeFs)(nil)
_ afero.Lstater = (*languageCompositeFs)(nil)
)
type languageCompositeFs struct {
*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{afero.NewCopyOnWriteFs(base, overlay).(*afero.CopyOnWriteFs)}
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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) {
m := make(map[string]FileMetaInfo)
getKey := func(fim FileMetaInfo) string {
return path.Join(fim.Meta().Lang(), fim.Name())
}
for _, fi := range lofi {
fim := fi.(FileMetaInfo)
m[getKey(fim)] = fim
}
for _, fi := range bofi {
fim := fi.(FileMetaInfo)
key := getKey(fim)
_, found := m[key]
if !found {
m[key] = fim
}
}
merged := make([]os.FileInfo, len(m))
i := 0
for _, v := range m {
merged[i] = v
i++
}
return merged, nil
}