hugo/hugolib/collections.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 hugolib
import (
"fmt"
"github.com/gohugoio/hugo/resources/resource"
"github.com/gohugoio/hugo/common/collections"
)
var (
_ collections.Grouper = (*Page)(nil)
_ collections.Slicer = (*Page)(nil)
_ collections.Slicer = PageGroup{}
_ collections.Slicer = WeightedPage{}
_ resource.ResourcesConverter = Pages{}
)
// collections.Slicer implementations below. We keep these bridge implementations
// here as it makes it easier to get an idea of "type coverage". These
// implementations have no value on their own.
// Slice is not meant to be used externally. It's a bridge function
// for the template functions. See collections.Slice.
func (p *Page) Slice(items interface{}) (interface{}, error) {
return toPages(items)
}
// Slice is not meant to be used externally. It's a bridge function
// for the template functions. See collections.Slice.
func (p PageGroup) Slice(in interface{}) (interface{}, error) {
switch items := in.(type) {
case PageGroup:
return items, nil
case []interface{}:
groups := make(PagesGroup, len(items))
for i, v := range items {
g, ok := v.(PageGroup)
if !ok {
return nil, fmt.Errorf("type %T is not a PageGroup", v)
}
groups[i] = g
}
return groups, nil
default:
return nil, fmt.Errorf("invalid slice type %T", items)
}
}
// Slice is not meant to be used externally. It's a bridge function
// for the template functions. See collections.Slice.
func (p WeightedPage) Slice(in interface{}) (interface{}, error) {
switch items := in.(type) {
case WeightedPages:
return items, nil
case []interface{}:
weighted := make(WeightedPages, len(items))
for i, v := range items {
g, ok := v.(WeightedPage)
if !ok {
return nil, fmt.Errorf("type %T is not a WeightedPage", v)
}
weighted[i] = g
}
return weighted, nil
default:
return nil, fmt.Errorf("invalid slice type %T", items)
}
}
// collections.Grouper implementations below
// Group creates a PageGroup from a key and a Pages object
// This method is not meant for external use. It got its non-typed arguments to satisfy
// a very generic interface in the tpl package.
func (p *Page) Group(key interface{}, in interface{}) (interface{}, error) {
pages, err := toPages(in)
if err != nil {
return nil, err
}
return PageGroup{Key: key, Pages: pages}, nil
}
// ToResources wraps resource.ResourcesConverter
func (pages Pages) ToResources() resource.Resources {
r := make(resource.Resources, len(pages))
for i, p := range pages {
r[i] = p
}
return r
}