hugo/tpl/template.go
Bjørn Erik Pedersen a03c631c42
Rework template handling for function and map lookups
This is a big commit, but it deletes lots of code and simplifies a lot.

* Resolving the template funcs at execution time means we don't have to create template clones per site
* Having a custom map resolver means that we can remove the AST lower case transformation for the special lower case Params map

Not only is the above easier to reason about, it's also faster, especially if you have more than one language, as in the benchmark below:

```
name                          old time/op    new time/op    delta
SiteNew/Deep_content_tree-16    53.7ms ± 0%    48.1ms ± 2%  -10.38%  (p=0.029 n=4+4)

name                          old alloc/op   new alloc/op   delta
SiteNew/Deep_content_tree-16    41.0MB ± 0%    36.8MB ± 0%  -10.26%  (p=0.029 n=4+4)

name                          old allocs/op  new allocs/op  delta
SiteNew/Deep_content_tree-16      481k ± 0%      410k ± 0%  -14.66%  (p=0.029 n=4+4)
```

This should be even better if you also have lots of templates.

Closes #6594
2019-12-12 10:04:35 +01:00

127 lines
3.4 KiB
Go

// 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 tpl
import (
"reflect"
"io"
"regexp"
"github.com/gohugoio/hugo/output"
texttemplate "github.com/gohugoio/hugo/tpl/internal/go_templates/texttemplate"
)
var _ TemplateInfoProvider = (*TemplateInfo)(nil)
// TemplateManager manages the collection of templates.
type TemplateManager interface {
TemplateHandler
TemplateFuncGetter
AddTemplate(name, tpl string) error
AddLateTemplate(name, tpl string) error
LoadTemplates(prefix string) error
MarkReady() error
RebuildClone()
}
// TemplateVariants describes the possible variants of a template.
// All of these may be empty.
type TemplateVariants struct {
Language string
OutputFormat output.Format
}
// TemplateFinder finds templates.
type TemplateFinder interface {
TemplateLookup
TemplateLookupVariant
}
// TemplateHandler finds and executes templates.
type TemplateHandler interface {
TemplateFinder
Execute(t Template, wr io.Writer, data interface{}) error
}
type TemplateLookup interface {
Lookup(name string) (Template, bool)
}
type TemplateLookupVariant interface {
// TODO(bep) this currently only works for shortcodes.
// We may unify and expand this variant pattern to the
// other templates, but we need this now for the shortcodes to
// quickly determine if a shortcode has a template for a given
// output format.
// It returns the template, if it was found or not and if there are
// alternative representations (output format, language).
// We are currently only interested in output formats, so we should improve
// this for speed.
LookupVariant(name string, variants TemplateVariants) (Template, bool, bool)
}
// Template is the common interface between text/template and html/template.
type Template interface {
Name() string
Prepare() (*texttemplate.Template, error)
}
// TemplateInfoProvider provides some contextual information about a template.
type TemplateInfoProvider interface {
TemplateInfo() Info
}
// TemplateParser is used to parse ad-hoc templates, e.g. in the Resource chain.
type TemplateParser interface {
Parse(name, tpl string) (Template, error)
}
// TemplateParseFinder provides both parsing and finding.
type TemplateParseFinder interface {
TemplateParser
TemplateFinder
}
// TemplateDebugger prints some debug info to stdoud.
type TemplateDebugger interface {
Debug()
}
// TemplateInfo wraps a Template with some additional information.
type TemplateInfo struct {
Template
Info Info
}
var baseOfRe = regexp.MustCompile("template: (.*?):")
func extractBaseOf(err string) string {
m := baseOfRe.FindStringSubmatch(err)
if len(m) == 2 {
return m[1]
}
return ""
}
func (t *TemplateInfo) TemplateInfo() Info {
return t.Info
}
// TemplateFuncGetter allows to find a template func by name.
type TemplateFuncGetter interface {
GetFunc(name string) (reflect.Value, bool)
}