52 lines
1.3 KiB
Go
52 lines
1.3 KiB
Go
// Copyright 2019 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package lazytemplate is a thin wrapper over text/template, allowing the use
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// of global template variables without forcing them to be parsed at init.
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package lazytemplate
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import (
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"io"
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"os"
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"strings"
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"sync"
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"text/template"
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)
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// Template is a wrapper around text/template.Template, where the underlying
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// template will be parsed the first time it is needed.
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type Template struct {
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name, text string
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once sync.Once
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tmpl *template.Template
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}
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func (r *Template) tp() *template.Template {
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r.once.Do(r.build)
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return r.tmpl
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}
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func (r *Template) build() {
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r.tmpl = template.Must(template.New(r.name).Parse(r.text))
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r.name, r.text = "", ""
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}
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func (r *Template) Execute(w io.Writer, data any) error {
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return r.tp().Execute(w, data)
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}
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var inTest = len(os.Args) > 0 && strings.HasSuffix(strings.TrimSuffix(os.Args[0], ".exe"), ".test")
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// New creates a new lazy template, delaying the parsing work until it is first
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// needed. If the code is being run as part of tests, the template parsing will
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// happen immediately.
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func New(name, text string) *Template {
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lt := &Template{name: name, text: text}
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if inTest {
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// In tests, always parse the templates early.
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lt.tp()
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}
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return lt
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}
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