ref: 837e084bbe53e9e2e6cd471d2a3daf273a874d92
dir: /output/layout.go/
// Copyright 2017-present 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 output
import (
"strings"
"sync"
"github.com/gohugoio/hugo/helpers"
)
// These may be used as content sections with potential conflicts. Avoid that.
var reservedSections = map[string]bool{
"shortcodes": true,
"partials": true,
}
// LayoutDescriptor describes how a layout should be chosen. This is
// typically built from a Page.
type LayoutDescriptor struct {
Type string
Section string
Kind string
Lang string
Layout string
// LayoutOverride indicates what we should only look for the above layout.
LayoutOverride bool
RenderingHook bool
Baseof bool
}
func (d LayoutDescriptor) isList() bool {
return !d.RenderingHook && d.Kind != "page" && d.Kind != "404"
}
// LayoutHandler calculates the layout template to use to render a given output type.
type LayoutHandler struct {
mu sync.RWMutex
cache map[layoutCacheKey][]string
}
type layoutCacheKey struct {
d LayoutDescriptor
f string
}
// NewLayoutHandler creates a new LayoutHandler.
func NewLayoutHandler() *LayoutHandler {
return &LayoutHandler{cache: make(map[layoutCacheKey][]string)}
}
// For returns a layout for the given LayoutDescriptor and options.
// Layouts are rendered and cached internally.
func (l *LayoutHandler) For(d LayoutDescriptor, f Format) ([]string, error) {
// We will get lots of requests for the same layouts, so avoid recalculations.
key := layoutCacheKey{d, f.Name}
l.mu.RLock()
if cacheVal, found := l.cache[key]; found {
l.mu.RUnlock()
return cacheVal, nil
}
l.mu.RUnlock()
layouts := resolvePageTemplate(d, f)
layouts = helpers.UniqueStringsReuse(layouts)
l.mu.Lock()
l.cache[key] = layouts
l.mu.Unlock()
return layouts, nil
}
type layoutBuilder struct {
layoutVariations []string
typeVariations []string
d LayoutDescriptor
f Format
}
func (l *layoutBuilder) addLayoutVariations(vars ...string) {
for _, layoutVar := range vars {
if l.d.Baseof && layoutVar != "baseof" {
l.layoutVariations = append(l.layoutVariations, layoutVar+"-baseof")
continue
}
if !l.d.RenderingHook && !l.d.Baseof && l.d.LayoutOverride && layoutVar != l.d.Layout {
continue
}
l.layoutVariations = append(l.layoutVariations, layoutVar)
}
}
func (l *layoutBuilder) addTypeVariations(vars ...string) {
for _, typeVar := range vars {
if !reservedSections[typeVar] {
if l.d.RenderingHook {
typeVar = typeVar + renderingHookRoot
}
l.typeVariations = append(l.typeVariations, typeVar)
}
}
}
func (l *layoutBuilder) addSectionType() {
if l.d.Section != "" {
l.addTypeVariations(l.d.Section)
}
}
func (l *layoutBuilder) addKind() {
l.addLayoutVariations(l.d.Kind)
l.addTypeVariations(l.d.Kind)
}
const renderingHookRoot = "/_markup"
func resolvePageTemplate(d LayoutDescriptor, f Format) []string {
b := &layoutBuilder{d: d, f: f}
if !d.RenderingHook && d.Layout != "" {
b.addLayoutVariations(d.Layout)
}
if d.Type != "" {
b.addTypeVariations(d.Type)
}
if d.RenderingHook {
b.addLayoutVariations(d.Kind)
b.addSectionType()
}
switch d.Kind {
case "page":
b.addLayoutVariations("single")
b.addSectionType()
case "home":
b.addLayoutVariations("index", "home")
// Also look in the root
b.addTypeVariations("")
case "section":
if d.Section != "" {
b.addLayoutVariations(d.Section)
}
b.addSectionType()
b.addKind()
case "term":
b.addKind()
if d.Section != "" {
b.addLayoutVariations(d.Section)
}
b.addLayoutVariations("taxonomy")
b.addTypeVariations("taxonomy")
b.addSectionType()
case "taxonomy":
if d.Section != "" {
b.addLayoutVariations(d.Section + ".terms")
}
b.addSectionType()
b.addLayoutVariations("terms")
// For legacy reasons this is deliberately put last.
b.addKind()
case "404":
b.addLayoutVariations("404")
b.addTypeVariations("")
}
isRSS := f.Name == RSSFormat.Name
if !d.RenderingHook && !d.Baseof && isRSS {
// The historic and common rss.xml case
b.addLayoutVariations("")
}
if d.Baseof || d.Kind != "404" {
// Most have _default in their lookup path
b.addTypeVariations("_default")
}
if d.isList() {
// Add the common list type
b.addLayoutVariations("list")
}
if d.Baseof {
b.addLayoutVariations("baseof")
}
layouts := b.resolveVariations()
if !d.RenderingHook && !d.Baseof && isRSS {
layouts = append(layouts, "_internal/_default/rss.xml")
}
return layouts
}
func (l *layoutBuilder) resolveVariations() []string {
var layouts []string
var variations []string
name := strings.ToLower(l.f.Name)
if l.d.Lang != "" {
// We prefer the most specific type before language.
variations = append(variations, []string{l.d.Lang + "." + name, name, l.d.Lang}...)
} else {
variations = append(variations, name)
}
variations = append(variations, "")
for _, typeVar := range l.typeVariations {
for _, variation := range variations {
for _, layoutVar := range l.layoutVariations {
if variation == "" && layoutVar == "" {
continue
}
s := constructLayoutPath(typeVar, layoutVar, variation, l.f.MediaType.Suffix())
if s != "" {
layouts = append(layouts, s)
}
}
}
}
return layouts
}
// constructLayoutPath constructs a layout path given a type, layout,
// variations, and extension. The path constructed follows the pattern of
// type/layout.variations.extension. If any value is empty, it will be left out
// of the path construction.
//
// Path construction requires at least 2 of 3 out of layout, variations, and extension.
// If more than one of those is empty, an empty string is returned.
func constructLayoutPath(typ, layout, variations, extension string) string {
// we already know that layout and variations are not both empty because of
// checks in resolveVariants().
if extension == "" && (layout == "" || variations == "") {
return ""
}
// Commence valid path construction...
var (
p strings.Builder
needDot bool
)
if typ != "" {
p.WriteString(typ)
p.WriteString("/")
}
if layout != "" {
p.WriteString(layout)
needDot = true
}
if variations != "" {
if needDot {
p.WriteString(".")
}
p.WriteString(variations)
needDot = true
}
if extension != "" {
if needDot {
p.WriteString(".")
}
p.WriteString(extension)
}
return p.String()
}