treewide: Use argparse.FileType in more places

Convert some scripts to use `argparse.FileType` where the change is relatively
easily doable. This allows better error messages as e.g. missing input files
will be detected during argument parsing. And it also makes writing to stdout
in absence of an explicit argument simpler.

Signed-off-by: Barnabás Pőcze <barnabas.pocze@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

utils/codegen/gen-gst-controls.py

@@ -138,18 +138,20 @@ def extend_control(ctrl):
 def main(argv):
     # Parse command line arguments
     parser = argparse.ArgumentParser()
-    parser.add_argument('--output', '-o', metavar='file', type=str,
+    parser.add_argument('--output', '-o', metavar='file', default=sys.stdout,
+                        type=argparse.FileType('w', encoding='utf-8'),
                         help='Output file name. Defaults to standard output if not specified.')
-    parser.add_argument('--template', '-t', dest='template', type=str, required=True,
+    parser.add_argument('--template', '-t', dest='template', required=True,
+                        type=argparse.FileType('r', encoding='utf-8'),
                         help='Template file name.')
-    parser.add_argument('input', type=str, nargs='+',
+    parser.add_argument('input', nargs='+', type=argparse.FileType('rb'),
                         help='Input file name.')
 
     args = parser.parse_args(argv[1:])
 
     controls = {}
     for input in args.input:
-        data = yaml.safe_load(open(input, 'rb').read())
+        data = yaml.safe_load(input)
 
         vendor = data['vendor']
         ctrls = controls.setdefault(vendor, [])
@@ -167,14 +169,10 @@ def main(argv):
     env.filters['indent_str'] = indent_str
     env.filters['snake_case'] = snake_case
     env.filters['kebab_case'] = kebab_case
-    template = env.from_string(open(args.template, 'r', encoding='utf-8').read())
+    template = env.from_string(args.template.read())
     string = template.render(data)
 
-    if args.output:
-        with open(args.output, 'w', encoding='utf-8') as output:
-            output.write(string)
-    else:
-        sys.stdout.write(string)
+    args.output.write(string)
 
     return 0