hugo/tpl/partials/partials.go

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// Copyright 2017 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 partials
import (
"fmt"
"html/template"
"strings"
"sync"
texttemplate "text/template"
bp "github.com/gohugoio/hugo/bufferpool"
"github.com/gohugoio/hugo/deps"
)
// TestTemplateProvider is global deps.ResourceProvider.
// NOTE: It's currently unused.
var TestTemplateProvider deps.ResourceProvider
// partialCache represents a cache of partials protected by a mutex.
type partialCache struct {
sync.RWMutex
p map[string]interface{}
}
// New returns a new instance of the templates-namespaced template functions.
func New(deps *deps.Deps) *Namespace {
return &Namespace{
deps: deps,
cachedPartials: partialCache{p: make(map[string]interface{})},
}
}
// Namespace provides template functions for the "templates" namespace.
type Namespace struct {
deps *deps.Deps
cachedPartials partialCache
}
// Include executes the named partial and returns either a string,
// when the partial is a text/template, or template.HTML when html/template.
func (ns *Namespace) Include(name string, contextList ...interface{}) (interface{}, error) {
if strings.HasPrefix("partials/", name) {
name = name[8:]
}
var context interface{}
if len(contextList) == 0 {
context = nil
} else {
context = contextList[0]
}
for _, n := range []string{"partials/" + name, "theme/partials/" + name} {
templ := ns.deps.Tmpl.Lookup(n)
if templ == nil {
// For legacy reasons.
templ = ns.deps.Tmpl.Lookup(n + ".html")
}
if templ != nil {
b := bp.GetBuffer()
defer bp.PutBuffer(b)
if err := templ.Execute(b, context); err != nil {
return "", err
}
if _, ok := templ.Template.(*texttemplate.Template); ok {
return b.String(), nil
}
return template.HTML(b.String()), nil
}
}
return "", fmt.Errorf("Partial %q not found", name)
}
// getCached executes and caches partial templates. An optional variant
// string parameter (a string slice actually, but be only use a variadic
// argument to make it optional) can be passed so that a given partial can have
// multiple uses. The cache is created with name+variant as the key.
func (ns *Namespace) getCached(name string, context interface{}, variant ...string) (interface{}, error) {
key := name
if len(variant) > 0 {
for i := 0; i < len(variant); i++ {
key += variant[i]
}
}
return ns.getOrCreate(key, name, context)
}
func (ns *Namespace) getOrCreate(key, name string, context interface{}) (p interface{}, err error) {
var ok bool
ns.cachedPartials.RLock()
p, ok = ns.cachedPartials.p[key]
ns.cachedPartials.RUnlock()
if ok {
return
}
ns.cachedPartials.Lock()
if p, ok = ns.cachedPartials.p[key]; !ok {
ns.cachedPartials.Unlock()
p, err = ns.Include(name, context)
ns.cachedPartials.Lock()
ns.cachedPartials.p[key] = p
}
ns.cachedPartials.Unlock()
return
}