hugo/resources/page/weighted.go

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// Copyright 2019 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 page
import (
"fmt"
"sort"
"github.com/gohugoio/hugo/common/collections"
)
var (
_ collections.Slicer = WeightedPage{}
)
// WeightedPages is a list of Pages with their corresponding (and relative) weight
// [{Weight: 30, Page: *1}, {Weight: 40, Page: *2}]
type WeightedPages []WeightedPage
// Page will return the Page (of Kind taxonomyList) that represents this set
// of pages. This method will panic if p is empty, as that should never happen.
func (p WeightedPages) Page() Page {
if len(p) == 0 {
panic("WeightedPages is empty")
}
first := p[0]
// TODO(bep) fix tests
if first.owner == nil {
return nil
}
return first.owner
}
// A WeightedPage is a Page with a weight.
type WeightedPage struct {
Weight int
Page
// Reference to the owning Page. This avoids having to do
// manual .Site.GetPage lookups. It is implemented in this roundabout way
// because we cannot add additional state to the WeightedPages slice
// without breaking lots of templates in the wild.
owner Page
}
func NewWeightedPage(weight int, p Page, owner Page) WeightedPage {
return WeightedPage{Weight: weight, Page: p, owner: owner}
}
func (w WeightedPage) String() string {
return fmt.Sprintf("WeightedPage(%d,%q)", w.Weight, w.Page.Title())
}
// 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)
}
}
// Pages returns the Pages in this weighted page set.
func (wp WeightedPages) Pages() Pages {
pages := make(Pages, len(wp))
for i := range wp {
pages[i] = wp[i].Page
}
return pages
}
// Prev returns the previous Page relative to the given Page in
// this weighted page set.
func (wp WeightedPages) Prev(cur Page) Page {
for x, c := range wp {
if c.Page == cur {
if x == 0 {
return wp[len(wp)-1].Page
}
return wp[x-1].Page
}
}
return nil
}
// Next returns the next Page relative to the given Page in
// this weighted page set.
func (wp WeightedPages) Next(cur Page) Page {
for x, c := range wp {
if c.Page == cur {
if x < len(wp)-1 {
return wp[x+1].Page
}
return wp[0].Page
}
}
return nil
}
func (wp WeightedPages) Len() int { return len(wp) }
func (wp WeightedPages) Swap(i, j int) { wp[i], wp[j] = wp[j], wp[i] }
// Sort stable sorts this weighted page set.
func (wp WeightedPages) Sort() { sort.Stable(wp) }
// Count returns the number of pages in this weighted page set.
func (wp WeightedPages) Count() int { return len(wp) }
func (wp WeightedPages) Less(i, j int) bool {
if wp[i].Weight == wp[j].Weight {
return DefaultPageSort(wp[i].Page, wp[j].Page)
}
return wp[i].Weight < wp[j].Weight
}