Merge pull request #33 from dterei/master

Add comment support + temporary file before writing

stringer.go

@@ -31,6 +31,17 @@ import (
 	"github.com/pascaldekloe/name"
 )
 
+type arrayFlags []string
+
+func (af arrayFlags) String() string {
+	return strings.Join(af, "")
+}
+
+func (af *arrayFlags) Set(value string) error {
+	*af = append(*af, value)
+	return nil
+}
+
 var (
 	typeNames       = flag.String("type", "", "comma-separated list of type names; must be set")
 	sql             = flag.Bool("sql", false, "if true, the Scanner and Valuer interface will be implemented.")
@@ -42,13 +53,19 @@ var (
 	trimPrefix      = flag.String("trimprefix", "", "transform each item name by removing a prefix. Default: \"\"")
 )
 
+var comments arrayFlags
+
+func init() {
+	flag.Var(&comments, "comment", "comments to include in generated code, can repeat. Default: \"\"")
+}
+
 // Usage is a replacement usage function for the flags package.
 func Usage() {
 	fmt.Fprintf(os.Stderr, "Usage of %s:\n", os.Args[0])
-	fmt.Fprintf(os.Stderr, "\tstringer [flags] -type T [directory]\n")
-	fmt.Fprintf(os.Stderr, "\tstringer [flags] -type T files... # Must be a single package\n")
+	fmt.Fprintf(os.Stderr, "\tenumer [flags] -type T [directory]\n")
+	fmt.Fprintf(os.Stderr, "\tenumer [flags] -type T files... # Must be a single package\n")
 	fmt.Fprintf(os.Stderr, "For more information, see:\n")
-	fmt.Fprintf(os.Stderr, "\thttp://godoc.org/golang.org/x/tools/cmd/stringer\n")
+	fmt.Fprintf(os.Stderr, "\thttps://github.com/alvaroloes/enumer\n")
 	fmt.Fprintf(os.Stderr, "Flags:\n")
 	flag.PrintDefaults()
 }
@@ -88,6 +105,7 @@ func main() {
 	// Print the header and package clause.
 	g.Printf("// Code generated by \"enumer %s\"; DO NOT EDIT.\n", strings.Join(os.Args[1:], " "))
 	g.Printf("\n")
+	g.Printf("// %s\n", comments.String())
 	g.Printf("package %s", g.pkg.name)
 	g.Printf("\n")
 	g.Printf("import (\n")
@@ -108,16 +126,31 @@ func main() {
 	// Format the output.
 	src := g.format()
 
-	// Write to file.
+	// Figure out filename to write to
 	outputName := *output
 	if outputName == "" {
 		baseName := fmt.Sprintf("%s_enumer.go", types[0])
 		outputName = filepath.Join(dir, strings.ToLower(baseName))
 	}
-	err := ioutil.WriteFile(outputName, src, 0644)
+
+	// Write to tmpfile first
+	tmpFile, err := ioutil.TempFile("", fmt.Sprintf("%s_enumer_", types[0]))
 	if err != nil {
+		log.Fatalf("creating temporary file for output: %s", err)
+	}
+	_, err = tmpFile.Write(src)
+	if err != nil {
+		tmpFile.Close()
+		os.Remove(tmpFile.Name())
 		log.Fatalf("writing output: %s", err)
 	}
+	tmpFile.Close()
+
+	// Rename tmpfile to output file
+	err = os.Rename(tmpFile.Name(), outputName)
+	if err != nil {
+		log.Fatalf("moving tempfile to output file: %s", err)
+	}
 }
 
 // isDirectory reports whether the named file is a directory.