github.com/fighterlyt/hugo@v0.47.1/hugofs/language_composite_fs.go (about)

     1  // Copyright 2018 The Hugo Authors. All rights reserved.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  // http://www.apache.org/licenses/LICENSE-2.0
     7  //
     8  // Unless required by applicable law or agreed to in writing, software
     9  // distributed under the License is distributed on an "AS IS" BASIS,
    10  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    11  // See the License for the specific language governing permissions and
    12  // limitations under the License.
    13  
    14  package hugofs
    15  
    16  import (
    17  	"github.com/spf13/afero"
    18  )
    19  
    20  var (
    21  	_ afero.Fs      = (*languageCompositeFs)(nil)
    22  	_ afero.Lstater = (*languageCompositeFs)(nil)
    23  )
    24  
    25  type languageCompositeFs struct {
    26  	*afero.CopyOnWriteFs
    27  }
    28  
    29  // NewLanguageCompositeFs creates a composite and language aware filesystem.
    30  // This is a hybrid filesystem. To get a specific file in Open, Stat etc., use the full filename
    31  // to the target filesystem. This information is available in Readdir, Stat etc. via the
    32  // special LanguageFileInfo FileInfo implementation.
    33  func NewLanguageCompositeFs(base afero.Fs, overlay *LanguageFs) afero.Fs {
    34  	return afero.NewReadOnlyFs(&languageCompositeFs{afero.NewCopyOnWriteFs(base, overlay).(*afero.CopyOnWriteFs)})
    35  }
    36  
    37  // Open takes the full path to the file in the target filesystem. If it is a directory, it gets merged
    38  // using the language as a weight.
    39  func (fs *languageCompositeFs) Open(name string) (afero.File, error) {
    40  	f, err := fs.CopyOnWriteFs.Open(name)
    41  	if err != nil {
    42  		return nil, err
    43  	}
    44  
    45  	fu, ok := f.(*afero.UnionFile)
    46  	if ok {
    47  		// This is a directory: Merge it.
    48  		fu.Merger = LanguageDirsMerger
    49  	}
    50  	return f, nil
    51  }