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// Copyright 2016 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 tplimpl
import (
"errors"
"fmt"
"strings"
htmltemplate "github.com/gohugoio/hugo/tpl/internal/go_templates/htmltemplate"
texttemplate "github.com/gohugoio/hugo/tpl/internal/go_templates/texttemplate"
"github.com/gohugoio/hugo/tpl/internal/go_templates/texttemplate/parse"
"github.com/gohugoio/hugo/common/hashing"
"github.com/gohugoio/hugo/common/maps"
"github.com/gohugoio/hugo/tpl"
"github.com/mitchellh/mapstructure"
)
type templateType int
const (
templateUndefined templateType = iota
templateShortcode
templatePartial
)
type templateContext struct {
visited map[string]bool
templateNotFound map[string]bool
deferNodes map[string]*parse.ListNode
lookupFn func(name string) *templateState
// The last error encountered.
err error
// Set when we're done checking for config header.
configChecked bool
t *templateState
// Store away the return node in partials.
returnNode *parse.CommandNode
}
func (c templateContext) getIfNotVisited(name string) *templateState {
if c.visited[name] {
return nil
}
c.visited[name] = true
templ := c.lookupFn(name)
if templ == nil {
// This may be a inline template defined outside of this file
// and not yet parsed. Unusual, but it happens.
// Store the name to try again later.
c.templateNotFound[name] = true
}
return templ
}
func newTemplateContext(
t *templateState,
lookupFn func(name string) *templateState,
) *templateContext {
return &templateContext{
t: t,
lookupFn: lookupFn,
visited: make(map[string]bool),
templateNotFound: make(map[string]bool),
deferNodes: make(map[string]*parse.ListNode),
}
}
func applyTemplateTransformers(
t *templateState,
lookupFn func(name string) *templateState,
) (*templateContext, error) {
if t == nil {
return nil, errors.New("expected template, but none provided")
}
c := newTemplateContext(t, lookupFn)
tree := getParseTree(t.Template)
_, err := c.applyTransformations(tree.Root)
if err == nil && c.returnNode != nil {
// This is a partial with a return statement.
c.t.parseInfo.HasReturn = true
tree.Root = c.wrapInPartialReturnWrapper(tree.Root)
}
return c, err
}
func getParseTree(templ tpl.Template) *parse.Tree {
templ = unwrap(templ)
if text, ok := templ.(*texttemplate.Template); ok {
return text.Tree
}
return templ.(*htmltemplate.Template).Tree
}
const (
// We parse this template and modify the nodes in order to assign
// the return value of a partial to a contextWrapper via Set. We use
// "range" over a one-element slice so we can shift dot to the
// partial's argument, Arg, while allowing Arg to be falsy.
partialReturnWrapperTempl = `{{ $_hugo_dot := $ }}{{ $ := .Arg }}{{ range (slice .Arg) }}{{ $_hugo_dot.Set ("PLACEHOLDER") }}{{ end }}`
doDeferTempl = `{{ doDefer ("PLACEHOLDER1") ("PLACEHOLDER2") }}`
)
var (
partialReturnWrapper *parse.ListNode
doDefer *parse.ListNode
)
func init() {
templ, err := texttemplate.New("").Parse(partialReturnWrapperTempl)
if err != nil {
panic(err)
}
partialReturnWrapper = templ.Tree.Root
templ, err = texttemplate.New("").Funcs(texttemplate.FuncMap{"doDefer": func(string, string) string { return "" }}).Parse(doDeferTempl)
if err != nil {
panic(err)
}
doDefer = templ.Tree.Root
}
// wrapInPartialReturnWrapper copies and modifies the parsed nodes of a
// predefined partial return wrapper to insert those of a user-defined partial.
func (c *templateContext) wrapInPartialReturnWrapper(n *parse.ListNode) *parse.ListNode {
wrapper := partialReturnWrapper.CopyList()
rangeNode := wrapper.Nodes[2].(*parse.RangeNode)
retn := rangeNode.List.Nodes[0]
setCmd := retn.(*parse.ActionNode).Pipe.Cmds[0]
setPipe := setCmd.Args[1].(*parse.PipeNode)
// Replace PLACEHOLDER with the real return value.
// Note that this is a PipeNode, so it will be wrapped in parens.
setPipe.Cmds = []*parse.CommandNode{c.returnNode}
rangeNode.List.Nodes = append(n.Nodes, retn)
return wrapper
}
// applyTransformations do 2 things:
// 1) Parses partial return statement.
// 2) Tracks template (partial) dependencies and some other info.
func (c *templateContext) applyTransformations(n parse.Node) (bool, error) {
switch x := n.(type) {
case *parse.ListNode:
if x != nil {
c.applyTransformationsToNodes(x.Nodes...)
}
case *parse.ActionNode:
c.applyTransformationsToNodes(x.Pipe)
case *parse.IfNode:
c.applyTransformationsToNodes(x.Pipe, x.List, x.ElseList)
case *parse.WithNode:
c.handleDefer(x)
c.applyTransformationsToNodes(x.Pipe, x.List, x.ElseList)
case *parse.RangeNode:
c.applyTransformationsToNodes(x.Pipe, x.List, x.ElseList)
case *parse.TemplateNode:
subTempl := c.getIfNotVisited(x.Name)
if subTempl != nil {
c.applyTransformationsToNodes(getParseTree(subTempl.Template).Root)
}
case *parse.PipeNode:
c.collectConfig(x)
for i, cmd := range x.Cmds {
keep, _ := c.applyTransformations(cmd)
if !keep {
x.Cmds = append(x.Cmds[:i], x.Cmds[i+1:]...)
}
}
case *parse.CommandNode:
c.collectInner(x)
keep := c.collectReturnNode(x)
for _, elem := range x.Args {
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