Factor code template into a file.

This allows code regeneration without rebuilding the generator binary.

cmd/goupnpdcpgen/dcp.go

@@ -7,10 +7,10 @@ import (
 	"os"
 	"sort"
 	"strings"
+	"text/template"
 
 	"github.com/huin/goupnp"
 	"github.com/huin/goupnp/scpd"
-	"github.com/huin/goutil/codegen"
 )
 
 // DCP collects together information about a UPnP Device Control Protocol.
@@ -86,20 +86,13 @@ func (dcp *DCP) processDeviceFile(file *zip.File) error {
 	return mainErr
 }
 
-func (dcp *DCP) writeCode(outFile string, useGofmt bool) error {
+func (dcp *DCP) writeCode(outFile string, codeTmpl *template.Template) error {
 	packageFile, err := os.Create(outFile)
 	if err != nil {
 		return err
 	}
 	var output io.WriteCloser = packageFile
-	if useGofmt {
+	if err = codeTmpl.Execute(output, dcp); err != nil {
-		if output, err = codegen.NewGofmtWriteCloser(output); err != nil {
-			packageFile.Close()
-			return err
-		}
-	}
-
-	if err = packageTmpl.Execute(output, dcp); err != nil {
 		output.Close()
 		return err
 	}

cmd/goupnpdcpgen/goupnpdcpgen.go

@@ -6,7 +6,9 @@ import (
 	"fmt"
 	"log"
 	"os"
+	"os/exec"
 	"path/filepath"
+	"text/template"
 )
 
 var (
@@ -22,15 +24,23 @@ func main() {
 		useGofmt = flag.Bool("gofmt", true, "Pass the generated code through gofmt. "+
 			"Disable this if debugging code generation and needing to see the generated code "+
 			"prior to being passed through gofmt.")
+		codeTmplFile = flag.String("code_tmpl_file", "", "Path to Go template to generate code from.")
 	)
 	flag.Parse()
 
-	if err := run(*dcpName, *specsDir, *useGofmt); err != nil {
+	if err := run(*dcpName, *specsDir, *useGofmt, *codeTmplFile); err != nil {
 		log.Fatal(err)
 	}
 }
 
-func run(dcpName, specsDir string, useGofmt bool) error {
+func run(dcpName, specsDir string, useGofmt bool, codeTmplFile string) error {
+	codeTmpl, err := template.New(filepath.Base(codeTmplFile)).Funcs(template.FuncMap{
+		"base": filepath.Base,
+	}).ParseFiles(codeTmplFile)
+	if err != nil {
+		return fmt.Errorf("error parsing template from file: %w", err)
+	}
+
 	if err := os.MkdirAll(specsDir, os.ModePerm); err != nil {
 		return fmt.Errorf("could not create specs-dir %q: %v", specsDir, err)
 	}
@@ -47,12 +57,22 @@ func run(dcpName, specsDir string, useGofmt bool) error {
 			return fmt.Errorf("error processing spec %s: %v", metadata.Name, err)
 		}
 
-		if err := dcp.writeCode(filepath.Base(metadata.Name)+".go", useGofmt); err != nil {
+		filename := filepath.Base(metadata.Name) + ".go"
+		if err := dcp.writeCode(filename, codeTmpl); err != nil {
 			return fmt.Errorf("error writing package %q: %v", dcp.Metadata.Name, err)
 		}
 
+		if !useGofmt {
 			return nil
 		}
 
+		return gofmt(filename)
+	}
+
 	return fmt.Errorf("could not find DCP with name %q", dcpName)
 }
+
+func gofmt(filename string) error {
+	cmd := exec.Command("gofmt", "-w", filename)
+	return cmd.Run()
+}

dcps/av1/gen.go

@@ -1,2 +1,2 @@
-//go:generate goupnpdcpgen -dcp_name av1
+//go:generate goupnpdcpgen -dcp_name av1 -code_tmpl_file ../dcps.gotemplate
 package av1

dcps/dcps.gotemplate

@@ -1,15 +1,4 @@
-package main
+{{$name := .Metadata.Name -}}
-
-import (
-	"html/template"
-	"path/filepath"
-)
-
-var templateFuncs = template.FuncMap{
-	"base": filepath.Base,
-}
-
-var packageTmpl = template.Must(template.New("package").Funcs(templateFuncs).Parse(`{{$name := .Metadata.Name}}
 // Client for UPnP Device Control Protocol {{.Metadata.OfficialName}}.
 // {{if .DocURLs}}
 // This DCP is documented in detail at: {{range .DocURLs}}
@@ -172,4 +161,3 @@ func (client *{{$srvIdent}}) {{.Name}}({{range $winargs -}}
 {{define "argstruct"}}struct {{"{"}}
 {{range .}}{{.Name}} string
 {{end}}{{"}"}}{{end}}
-`))

dcps/internetgateway1/gen.go

@@ -1,2 +1,2 @@
-//go:generate goupnpdcpgen -dcp_name internetgateway1
+//go:generate goupnpdcpgen -dcp_name internetgateway1 -code_tmpl_file ../dcps.gotemplate
 package internetgateway1

dcps/internetgateway2/gen.go

@@ -1,2 +1,2 @@
-//go:generate goupnpdcpgen -dcp_name internetgateway2
+//go:generate goupnpdcpgen -dcp_name internetgateway2 -code_tmpl_file ../dcps.gotemplate
 package internetgateway2

dcps/ocf/internetgateway2/gen.go

@@ -1,2 +1,2 @@
-//go:generate goupnpdcpgen -dcp_name ocf/internetgateway2
+//go:generate goupnpdcpgen -dcp_name ocf/internetgateway2 -code_tmpl_file ../../dcps.gotemplate
 package internetgateway2