github.com/SDLMoe/hugo@v0.47.1/hugolib/pages_language_merge.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 hugolib
    15  
    16  import (
    17  	"fmt"
    18  )
    19  
    20  var (
    21  	_ pagesLanguageMerger = (*Pages)(nil)
    22  )
    23  
    24  type pagesLanguageMerger interface {
    25  	MergeByLanguage(other Pages) Pages
    26  	// Needed for integration with the tpl package.
    27  	MergeByLanguageInterface(other interface{}) (interface{}, error)
    28  }
    29  
    30  // MergeByLanguage supplies missing translations in p1 with values from p2.
    31  // The result is sorted by the default sort order for pages.
    32  func (p1 Pages) MergeByLanguage(p2 Pages) Pages {
    33  	merge := func(pages *Pages) {
    34  		m := make(map[string]bool)
    35  		for _, p := range *pages {
    36  			m[p.TranslationKey()] = true
    37  		}
    38  
    39  		for _, p := range p2 {
    40  			if _, found := m[p.TranslationKey()]; !found {
    41  				*pages = append(*pages, p)
    42  			}
    43  		}
    44  
    45  		pages.Sort()
    46  	}
    47  
    48  	out, _ := spc.getP("pages.MergeByLanguage", merge, p1, p2)
    49  
    50  	return out
    51  }
    52  
    53  // MergeByLanguageInterface is the generic version of MergeByLanguage. It
    54  // is here just so it can be called from the tpl package.
    55  func (p1 Pages) MergeByLanguageInterface(in interface{}) (interface{}, error) {
    56  	if in == nil {
    57  		return p1, nil
    58  	}
    59  	p2, ok := in.(Pages)
    60  	if !ok {
    61  		return nil, fmt.Errorf("%T cannot be merged by language", in)
    62  	}
    63  	return p1.MergeByLanguage(p2), nil
    64  }