tools: add shell_quote() utility function

tools/util.py

@@ -39,6 +39,26 @@ def run_output(args, quiet=False, cwd=None, env=None, merge_env={}):
     return subprocess.check_output(args, cwd=cwd, env=env, shell=shell)
 
 
+def shell_quote_win(arg):
+    if re.search(r'[\x00-\x20"^%~!@&?*<>|()=]', arg):
+        # Double all " quote characters.
+        arg = arg.replace('"', '""')
+        # Wrap the entire string in " quotes.
+        arg = '"' + arg + '"'
+        # Double any N backslashes that are immediately followed by a " quote.
+        arg = re.sub(r'(\\+)(?=")', r'\1\1', arg)
+    return arg
+
+
+def shell_quote(arg):
+    if os.name == "nt":
+        return shell_quote_win(arg)
+    else:
+        # Python 2 has posix shell quoting built in, albeit in a weird place.
+        from pipes import quote
+        return quote(arg)
+
+
 def remove_and_symlink(target, name, target_is_dir=False):
     try:
         # On Windows, directory symlink can only be removed with rmdir().

tools/util_test.py

@@ -1,5 +1,5 @@
 # Copyright 2018 the Deno authors. All rights reserved. MIT license.
-from util import pattern_match, parse_exit_code
+from util import pattern_match, parse_exit_code, shell_quote_win
 
 
 def pattern_match_test():
@@ -34,9 +34,20 @@ def parse_exit_code_test():
     assert 0 == parse_exit_code('hello_world')
 
 
+def shell_quote_win_test():
+    print "Testing util.shell_quote_win()..."
+    assert 'simple' == shell_quote_win('simple')
+    assert 'roof/\\isoprojection' == shell_quote_win('roof/\\isoprojection')
+    assert '"with space"' == shell_quote_win('with space')
+    assert '"embedded""quote"' == shell_quote_win('embedded"quote')
+    assert '"a""b""""c\\d\\\\""e\\\\\\\\"' == shell_quote_win(
+        'a"b""c\\d\\"e\\\\')
+
+
 def util_test():
     pattern_match_test()
     parse_exit_code_test()
+    shell_quote_win_test()
 
 
 if __name__ == '__main__':