Use context managers for in and out

Author: mpkocher

Lib/json/tool.py

@@ -84,20 +84,23 @@ def main():
 
     try:
         if options.infile == '-':
-            infile = sys.stdin
+            in_f = sys.stdin.fileno()
         else:
-            infile = open(options.infile, encoding='utf-8')
-
-        if options.json_lines:
-            objs = (json.loads(line) for line in infile)
-        else:
-            objs = (json.load(infile),)
+            in_f = options.infile
 
         if options.outfile is None:
-            outfile = sys.stdout
+            out_f = sys.stdout.fileno()
         else:
-            outfile = open(options.outfile, 'w', encoding='utf-8')
-        with outfile:
+            out_f = options.outfile
+
+        with (open(in_f, 'r', encoding='utf-8') as infile,
+              open(out_f, 'w', encoding='utf-8') as outfile):
+
+            if options.json_lines:
+                objs = (json.loads(line) for line in infile)
+            else:
+                objs = [json.load(infile)]
+
             if can_colorize(file=outfile):
                 t = get_theme(tty_file=outfile).syntax
                 for obj in objs:
@@ -108,8 +111,7 @@ def main():
                 for obj in objs:
                     json.dump(obj, outfile, **dump_args)
                     outfile.write('\n')
-        if infile is not sys.stdin:
-            infile.close()
+
     except ValueError as e:
         raise SystemExit(e)