/
compile.go
156 lines (130 loc) · 3.76 KB
/
compile.go
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package tmpl
import (
"fmt"
"html/template"
"reflect"
"sync"
)
// CompilerOptions holds options that control the template compiler
type CompilerOptions struct {
// analyzers is a list of analyzers that are run before compilation
analyzers []Analyzer
// parseOpts are the options passed to the template parser
parseOpts ParseOptions
}
// CompilerOption is a function that can be used to modify the CompilerOptions
type CompilerOption func(opts *CompilerOptions)
func UseFuncs(funcs FuncMap) CompilerOption {
return func(opts *CompilerOptions) {
if opts.parseOpts.Funcs == nil {
opts.parseOpts.Funcs = funcs
} else {
for k, v := range funcs {
opts.parseOpts.Funcs[k] = v
}
}
}
}
func UseAnalyzers(analyzers ...Analyzer) CompilerOption {
return func(opts *CompilerOptions) {
opts.analyzers = append(opts.analyzers, analyzers...)
}
}
// UseParseOptions sets the ParseOptions for the template CompilerOptions. These
// options are used internally with the html/template package.
func UseParseOptions(parseOpts ParseOptions) CompilerOption {
return func(opts *CompilerOptions) {
opts.parseOpts = parseOpts
}
}
func compile(tp TemplateProvider, opts ParseOptions, analyzers ...Analyzer) (*template.Template, error) {
var (
err error
t *template.Template
)
helper, err := Analyze(tp, opts, analyzers)
if err != nil {
return nil, err
}
// recursively parse all templates into a single template instance
// this block is responsible for constructing the template that
// will be rendered by the user
err = recurseFieldsImplementing[TemplateProvider](tp, func(tp TemplateProvider, field reflect.StructField) error {
var templateText string
templateName, ok := field.Tag.Lookup("tmpl")
if !ok {
templateName = field.Name
}
if t == nil {
// if t is nil, that means this is the recursive entrypoint
// and some construction needs to happen
t = template.New(templateName)
templateText = tp.TemplateText()
t = t.Delims(opts.LeftDelim, opts.RightDelim)
// Analyzers can provide functions to be used in templates
t = t.Funcs(helper.FuncMap())
} else {
// if this is a nested template wrap its text in a {{ define }}
// statement, so it may be referenced by the "parent" template
// ex: {{define %q -}}\n%s{{end}}
templateText = fmt.Sprintf("%[1]sdefine %[3]q -%[2]s\n%[4]s%[1]send%[2]s\n", opts.LeftDelim, opts.RightDelim, templateName, tp.TemplateText())
}
t, err = t.Parse(templateText)
if err != nil {
return err
}
return nil
})
if err != nil {
return nil, fmt.Errorf("failed to compile template: %+v", err)
}
return t, nil
}
// Compile takes the given TemplateProvider, parses the templateProvider text and then
// recursively compiles all nested templates into one managed Template instance.
//
// Compile also spawns a watcher routine. If the given TemplateProvider or any
// nested templates within implement TemplateWatcher, they can send signals over
// the given channel when it is time for the templateProvider to be recompiled.
func Compile[T TemplateProvider](tp T, opts ...CompilerOption) (Template[T], error) {
var (
c = &CompilerOptions{
analyzers: builtinAnalyzers,
parseOpts: ParseOptions{
LeftDelim: "{{",
RightDelim: "}}",
},
}
)
for _, opt := range opts {
opt(c)
}
m := &managedTemplate[T]{
mu: &sync.RWMutex{},
}
doCompile := func() (err error) {
var (
t *template.Template
)
t, err = compile(tp, c.parseOpts, c.analyzers...)
if err != nil {
return
}
m.mu.Lock()
m.template = t
m.mu.Unlock()
return
}
err := doCompile()
if err != nil {
return nil, err
}
return m, nil
}
func MustCompile[T TemplateProvider](p T, opts ...CompilerOption) Template[T] {
tmpl, err := Compile(p, opts...)
if err != nil {
panic(err)
}
return tmpl
}