Cleanup code for reading response files (#6500)

Author: sbc100

emcc.py

@@ -332,7 +332,7 @@ def run():
     return 1
 
   # read response files very early on
-  substitute_response_files(sys.argv)
+  sys.argv = substitute_response_files(sys.argv)
 
   if len(sys.argv) == 1 or '--help' in sys.argv:
     # Documentation for emcc and its options must be updated in:

emscripten.py

@@ -2267,7 +2267,7 @@ def ensure_struct_info():
 
 
 def _main(args):
-  substitute_response_files(args)
+  args = substitute_response_files(args)
 
   parser = argparse.ArgumentParser(
     usage='%(prog)s [-h] [-H HEADERS] [-o OUTFILE] [-c COMPILER_ENGINE] [-s FOO=BAR]* infile',

tools/response_file.py

@@ -44,9 +44,8 @@ def read_response_file(response_filename):
   if not os.path.exists(response_filename):
     raise Exception("Response file '%s' not found!" % response_filename)
 
-  response_fd = open(response_filename, 'r')
-  args = response_fd.read()
-  response_fd.close()
+  with open(response_filename) as f:
+    args = f.read()
   args = shlex.split(args)
 
   if DEBUG:
@@ -57,12 +56,10 @@ def read_response_file(response_filename):
 
 def substitute_response_files(args):
   """Substitute any response files found in args with their contents."""
-  found = True
-  while found:
-    found = False
-    for index in range(len(args)):
-      if args[index].startswith('@'):
-        found = True
-        new_args = read_response_file(args[index])
-        args[index:index + 1] = new_args
-        break
+  new_args = []
+  for arg in args:
+    if arg.startswith('@'):
+      new_args += read_response_file(arg)
+    else:
+      new_args.append(arg)
+  return new_args