From b2f14afe4af1753b551f06bc2208d604214dfa0d Mon Sep 17 00:00:00 2001
From: haoxin <coderhaoxin@outlook.com>
Date: Sun, 1 Feb 2015 21:10:09 +0800
Subject: [PATCH] rewrite file only when file data changed

also fix #597
---
 js/lib/cli.js                   | 22 ++++++++++++----------
 python/jsbeautifier/__init__.py |  8 +++++---
 2 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/js/lib/cli.js b/js/lib/cli.js
index 1d25caad8..cf4ddedee 100755
--- a/js/lib/cli.js
+++ b/js/lib/cli.js
@@ -278,39 +278,41 @@ function processInputSync(filepath) {
         });
 
         input.on('end', function() {
-            makePretty(data, config, outfile, writePretty);
+            makePretty(data, config, filepath, outfile, writePretty);
         });
     } else {
         var dir = path.dirname(outfile);
         mkdirp.sync(dir);
         data = fs.readFileSync(filepath, 'utf8');
-        makePretty(data, config, outfile, writePretty);
+        makePretty(data, config, filepath, outfile, writePretty);
     }
 }
 
-function makePretty(code, config, outfile, callback) {
+function makePretty(code, config, filepath, outfile, callback) {
     try {
         var fileType = getOutputType(outfile, config.type);
         var pretty = beautify[fileType](code, config);
 
-        callback(null, pretty, outfile, config);
+        callback(null, pretty, filepath, outfile, config, code);
     } catch (ex) {
         callback(ex);
     }
 }
 
-function writePretty(err, pretty, outfile, config) {
+function writePretty(err, pretty, filepath, outfile, config, code) {
     if (err) {
         console.error(err);
         process.exit(1);
     }
 
     if (outfile) {
-        try {
-            fs.writeFileSync(outfile, pretty, 'utf8');
-            logToStdout('beautified ' + path.relative(process.cwd(), outfile), config);
-        } catch (ex) {
-            onOutputError(ex);
+        if (!(code === pretty && filepath === outfile)) {
+            try {
+                fs.writeFileSync(outfile, pretty, 'utf8');
+                logToStdout('beautified ' + path.relative(process.cwd(), outfile), config);
+            } catch (ex) {
+                onOutputError(ex);
+            }
         }
     } else {
         process.stdout.write(pretty);
diff --git a/python/jsbeautifier/__init__.py b/python/jsbeautifier/__init__.py
index 68baabe7d..928f25277 100644
--- a/python/jsbeautifier/__init__.py
+++ b/python/jsbeautifier/__init__.py
@@ -1730,9 +1730,11 @@ def main():
             if outfile == 'stdout':
                 sys.stdout.write(beautify_file(file, js_options))
             else:
-                mkdir_p(os.path.dirname(outfile))
-                with open(outfile, 'w') as f:
-                    f.write(beautify_file(file, js_options))
+                result = beautify_file(file, js_options)
+                if not (result == ''.join(open(file).readlines()) and file == outfile):
+                    mkdir_p(os.path.dirname(outfile))
+                    with open(outfile, 'w') as f:
+                        f.write(result)
         except Exception as ex:
             print(ex, file=sys.stderr)
             return 1