[process-stats-dir] Switch to buffered output

Unbuffered output is unsupported for non-binary
files.

Author: hamishknight

utils/process-stats-dir.py

@@ -560,13 +560,39 @@ def render_profiles(args):
             import webbrowser
             webbrowser.open_new_tab("file://" + os.path.abspath(index_path))
 
+def process(args):
+    if len(args.remainder) == 0:
+        parser.print_help()
+        return 1
+    if args.catapult:
+        write_catapult_trace(args)
+    elif args.compare_stats_dirs:
+        return compare_stats_dirs(args)
+    elif args.set_csv_baseline is not None:
+        return set_csv_baseline(args)
+    elif args.compare_to_csv_baseline is not None:
+        return compare_to_csv_baseline(args)
+    elif args.incrementality:
+        if args.paired:
+            show_paired_incrementality(args)
+        else:
+            show_incrementality(args)
+    elif args.lnt:
+        write_lnt_values(args)
+    elif args.evaluate:
+        return evaluate(args)
+    elif args.evaluate_delta:
+        return evaluate_delta(args)
+    elif args.render_profiles:
+        return render_profiles(args)
+    return None
 
 def main():
     parser = argparse.ArgumentParser()
     parser.add_argument("--verbose", action="store_true",
                         help="Report activity verbosely")
     parser.add_argument("--output", default="-",
-                        type=argparse.FileType('w', 0),
+                        type=argparse.FileType('w'),
                         help="Write output to file")
     parser.add_argument("--paired", action="store_true",
                         help="Process two dirs-of-stats-dirs, pairwise")
@@ -674,31 +700,9 @@ def main():
                         help="stats-dirs to process")
 
     args = parser.parse_args()
-    if len(args.remainder) == 0:
-        parser.print_help()
-        return 1
-    if args.catapult:
-        write_catapult_trace(args)
-    elif args.compare_stats_dirs:
-        return compare_stats_dirs(args)
-    elif args.set_csv_baseline is not None:
-        return set_csv_baseline(args)
-    elif args.compare_to_csv_baseline is not None:
-        return compare_to_csv_baseline(args)
-    elif args.incrementality:
-        if args.paired:
-            show_paired_incrementality(args)
-        else:
-            show_incrementality(args)
-    elif args.lnt:
-        write_lnt_values(args)
-    elif args.evaluate:
-        return evaluate(args)
-    elif args.evaluate_delta:
-        return evaluate_delta(args)
-    elif args.render_profiles:
-        return render_profiles(args)
-    return None
-
+    try:
+      return process(args)
+    finally:
+      args.output.close()
 
 sys.exit(main())