Support diffing files

main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"fmt"
 	"io/ioutil"
 	"log"
 	"os"
@@ -21,10 +22,10 @@ func main() {
 	}
 
 	cmd.Run = func(cmd *cli.Command, args []string) error {
-		if err := neatifyDir(args[0]); err != nil {
+		if err := statAndNeatifyPath(args[0]); err != nil {
 			return err
 		}
-		if err := neatifyDir(args[1]); err != nil {
+		if err := statAndNeatifyPath(args[1]); err != nil {
 			return err
 		}
 
@@ -39,6 +40,28 @@ func main() {
 	}
 }
 
+func statAndNeatifyPath(path string) error {
+	// Stat evaluates symlinks so they are supported (if they lead to dirs or regular files).
+	fi, err := os.Stat(path)
+	if err != nil {
+		return err
+	}
+	return neatify(path, fi.Mode())
+}
+
+// neatify calls the appropriate function for the file based on FileMode
+// neatify does not call Stat() because neatifyDir() aleady has FileInfo for the passed file
+func neatify(path string, fm os.FileMode) error {
+	if fm.IsDir() {
+		return neatifyDir(path)
+	}
+	if fm.IsRegular() {
+		return neatifyFile(path, fm)
+	}
+	return fmt.Errorf("Found file '%s' which is neither directory nor a regular file. "+
+		"Special files like named pipes or device files are not supported.", path)
+}
+
 func neatifyDir(dir string) error {
 	fis, err := ioutil.ReadDir(dir)
 	if err != nil {
@@ -47,20 +70,27 @@ func neatifyDir(dir string) error {
 
 	for _, fi := range fis {
 		filename := filepath.Join(dir, fi.Name())
-		data, err := ioutil.ReadFile(filename)
-		if err != nil {
+		if err = neatify(filename, fi.Mode()); err != nil {
 			return err
 		}
+	}
 
-		n, err := neat.NeatYAMLOrJSON(data)
-		if err != nil {
-			return err
-		}
+	return nil
+}
 
-		if err := ioutil.WriteFile(filename, []byte(n), fi.Mode()); err != nil {
-			return err
-		}
+func neatifyFile(filename string, fm os.FileMode) error {
+	data, err := ioutil.ReadFile(filename)
+	if err != nil {
+		return err
 	}
 
+	n, err := neat.NeatYAMLOrJSON(data)
+	if err != nil {
+		return err
+	}
+
+	if err := ioutil.WriteFile(filename, []byte(n), fm); err != nil {
+		return err
+	}
 	return nil
 }