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5758c370ea
Partials with returns values are parsed, then inserted into a partial return wrapper via wrapInPartialReturnWrapper in order to assign the return value via *contextWrapper.Set. The predefined wrapper template for partials inserts a partial's nodes into a "with" template action in order to set dot to a *contextWrapper within the partial. However, because "with" is skipped if its argument is falsy, partials with falsy arguments were not being evaluated. This replaces the "with" action in the partial wrapper with a "range" action that isn't skipped if .Arg is falsy. Fixes #7528
232 lines
5.7 KiB
Go
232 lines
5.7 KiB
Go
// Copyright 2017 The Hugo Authors. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// Package partials provides template functions for working with reusable
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// templates.
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package partials
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import (
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"errors"
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"fmt"
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"html/template"
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"io"
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"io/ioutil"
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"reflect"
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"strings"
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"sync"
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texttemplate "github.com/gohugoio/hugo/tpl/internal/go_templates/texttemplate"
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"github.com/gohugoio/hugo/helpers"
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"github.com/gohugoio/hugo/tpl"
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bp "github.com/gohugoio/hugo/bufferpool"
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"github.com/gohugoio/hugo/deps"
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)
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// TestTemplateProvider is global deps.ResourceProvider.
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// NOTE: It's currently unused.
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var TestTemplateProvider deps.ResourceProvider
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type partialCacheKey struct {
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name string
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variant interface{}
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}
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// partialCache represents a cache of partials protected by a mutex.
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type partialCache struct {
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sync.RWMutex
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p map[partialCacheKey]interface{}
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}
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func (p *partialCache) clear() {
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p.Lock()
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defer p.Unlock()
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p.p = make(map[partialCacheKey]interface{})
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}
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// New returns a new instance of the templates-namespaced template functions.
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func New(deps *deps.Deps) *Namespace {
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cache := &partialCache{p: make(map[partialCacheKey]interface{})}
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deps.BuildStartListeners.Add(
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func() {
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cache.clear()
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})
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return &Namespace{
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deps: deps,
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cachedPartials: cache,
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}
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}
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// Namespace provides template functions for the "templates" namespace.
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type Namespace struct {
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deps *deps.Deps
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cachedPartials *partialCache
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}
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// contextWrapper makes room for a return value in a partial invocation.
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type contextWrapper struct {
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Arg interface{}
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Result interface{}
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}
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// Set sets the return value and returns an empty string.
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func (c *contextWrapper) Set(in interface{}) string {
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c.Result = in
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return ""
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}
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// Include executes the named partial.
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// If the partial contains a return statement, that value will be returned.
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// Else, the rendered output will be returned:
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// A string if the partial is a text/template, or template.HTML when html/template.
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func (ns *Namespace) Include(name string, contextList ...interface{}) (interface{}, error) {
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name = strings.TrimPrefix(name, "partials/")
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var context interface{}
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if len(contextList) > 0 {
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context = contextList[0]
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}
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n := "partials/" + name
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templ, found := ns.deps.Tmpl().Lookup(n)
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if !found {
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// For legacy reasons.
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templ, found = ns.deps.Tmpl().Lookup(n + ".html")
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}
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if !found {
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return "", fmt.Errorf("partial %q not found", name)
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}
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var info tpl.ParseInfo
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if ip, ok := templ.(tpl.Info); ok {
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info = ip.ParseInfo()
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}
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var w io.Writer
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if info.HasReturn {
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// Wrap the context sent to the template to capture the return value.
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// Note that the template is rewritten to make sure that the dot (".")
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// and the $ variable points to Arg.
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context = &contextWrapper{
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Arg: context,
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}
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// We don't care about any template output.
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w = ioutil.Discard
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} else {
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b := bp.GetBuffer()
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defer bp.PutBuffer(b)
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w = b
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}
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if err := ns.deps.Tmpl().Execute(templ, w, context); err != nil {
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return "", err
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}
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var result interface{}
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if ctx, ok := context.(*contextWrapper); ok {
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result = ctx.Result
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} else if _, ok := templ.(*texttemplate.Template); ok {
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result = w.(fmt.Stringer).String()
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} else {
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result = template.HTML(w.(fmt.Stringer).String())
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}
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if ns.deps.Metrics != nil {
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ns.deps.Metrics.TrackValue(templ.Name(), result)
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}
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return result, nil
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}
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// IncludeCached executes and caches partial templates. The cache is created with name+variants as the key.
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func (ns *Namespace) IncludeCached(name string, context interface{}, variants ...interface{}) (interface{}, error) {
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key, err := createKey(name, variants...)
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if err != nil {
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return nil, err
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}
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result, err := ns.getOrCreate(key, context)
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if err == errUnHashable {
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// Try one more
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key.variant = helpers.HashString(key.variant)
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result, err = ns.getOrCreate(key, context)
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}
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return result, err
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}
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func createKey(name string, variants ...interface{}) (partialCacheKey, error) {
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var variant interface{}
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if len(variants) > 1 {
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variant = helpers.HashString(variants...)
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} else if len(variants) == 1 {
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variant = variants[0]
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t := reflect.TypeOf(variant)
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switch t.Kind() {
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// This isn't an exhaustive list of unhashable types.
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// There may be structs with slices,
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// but that should be very rare. We do recover from that situation
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// below.
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case reflect.Slice, reflect.Array, reflect.Map:
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variant = helpers.HashString(variant)
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}
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}
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return partialCacheKey{name: name, variant: variant}, nil
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}
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var errUnHashable = errors.New("unhashable")
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func (ns *Namespace) getOrCreate(key partialCacheKey, context interface{}) (result interface{}, err error) {
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defer func() {
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if r := recover(); r != nil {
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err = r.(error)
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if strings.Contains(err.Error(), "unhashable type") {
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ns.cachedPartials.RUnlock()
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err = errUnHashable
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}
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}
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}()
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ns.cachedPartials.RLock()
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p, ok := ns.cachedPartials.p[key]
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ns.cachedPartials.RUnlock()
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if ok {
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return p, nil
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}
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p, err = ns.Include(key.name, context)
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if err != nil {
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return nil, err
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}
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ns.cachedPartials.Lock()
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defer ns.cachedPartials.Unlock()
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// Double-check.
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if p2, ok := ns.cachedPartials.p[key]; ok {
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return p2, nil
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}
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ns.cachedPartials.p[key] = p
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return p, nil
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}
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