github.com/graemephi/kahugo@v0.62.3-0.20211121071557-d78c0423784d/hugolib/page_unwrap.go (about)

     1  // Copyright 2019 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  	"github.com/pkg/errors"
    18  
    19  	"github.com/gohugoio/hugo/resources/page"
    20  )
    21  
    22  // Wraps a Page.
    23  type pageWrapper interface {
    24  	page() page.Page
    25  }
    26  
    27  // unwrapPage is used in equality checks and similar.
    28  func unwrapPage(in interface{}) (page.Page, error) {
    29  	switch v := in.(type) {
    30  	case *pageState:
    31  		return v, nil
    32  	case pageWrapper:
    33  		return v.page(), nil
    34  	case page.Page:
    35  		return v, nil
    36  	case nil:
    37  		return nil, nil
    38  	default:
    39  		return nil, errors.Errorf("unwrapPage: %T not supported", in)
    40  	}
    41  }
    42  
    43  func mustUnwrapPage(in interface{}) page.Page {
    44  	p, err := unwrapPage(in)
    45  	if err != nil {
    46  		panic(err)
    47  	}
    48  
    49  	return p
    50  }