1 files changed, 66 insertions, 0 deletions
diff --git a/tools/scan-build-py/libscanbuild/shell.py b/tools/scan-build-py/libscanbuild/shell.py
new file mode 100644
index 0000000000..a575946a95
--- /dev/null
+++ b/tools/scan-build-py/libscanbuild/shell.py
@@ -0,0 +1,66 @@
+# -*- coding: utf-8 -*-
+#                     The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+""" This module implements basic shell escaping/unescaping methods. """
+
+import re
+import shlex
+
+__all__ = ['encode', 'decode']
+
+
+def encode(command):
+    """ Takes a command as list and returns a string. """
+
+    def needs_quote(word):
+        """ Returns true if arguments needs to be protected by quotes.
+
+        Previous implementation was shlex.split method, but that's not good
+        for this job. Currently is running through the string with a basic
+        state checking. """
+
+        reserved = {' ', '$', '%', '&', '(', ')', '[', ']', '{', '}', '*', '|',
+                    '<', '>', '@', '?', '!'}
+        state = 0
+        for current in word:
+            if state == 0 and current in reserved:
+                return True
+            elif state == 0 and current == '\\':
+                state = 1
+            elif state == 1 and current in reserved | {'\\'}:
+                state = 0
+            elif state == 0 and current == '"':
+                state = 2
+            elif state == 2 and current == '"':
+                state = 0
+            elif state == 0 and current == "'":
+                state = 3
+            elif state == 3 and current == "'":
+                state = 0
+        return state != 0
+
+    def escape(word):
+        """ Do protect argument if that's needed. """
+
+        table = {'\\': '\\\\', '"': '\\"'}
+        escaped = ''.join([table.get(c, c) for c in word])
+
+        return '"' + escaped + '"' if needs_quote(word) else escaped
+
+    return " ".join([escape(arg) for arg in command])
+
+
+def decode(string):
+    """ Takes a command string and returns as a list. """
+
+    def unescape(arg):
+        """ Gets rid of the escaping characters. """
+
+        if len(arg) >= 2 and arg[0] == arg[-1] and arg[0] == '"':
+            arg = arg[1:-1]
+            return re.sub(r'\\(["\\])', r'\1', arg)
+        return re.sub(r'\\([\\ $%&\(\)\[\]\{\}\*|<>@?!])', r'\1', arg)
+
+    return [unescape(arg) for arg in shlex.split(string)]