From 9f4eaf4234e6a7074fca72a3a9229d75035daac8 Mon Sep 17 00:00:00 2001
From: Tomas Gavenciak <gavento@ucw.cz>
Date: Tue, 23 Nov 2010 20:12:06 +0100
Subject: [PATCH] Added function config_escape

For safe constructon configuration commands as strings, tested, documented.
---
 t/doc/config.rst       |  9 ++++++++-
 t/moe/config_parser.py | 10 ++++++++++
 t/moe/config_test.py   |  4 ++++
 3 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/t/doc/config.rst b/t/doc/config.rst
index 3216a46..87e825e 100644
--- a/t/doc/config.rst
+++ b/t/doc/config.rst
@@ -7,6 +7,7 @@ Moe configuration
 =================
 
 .. contents:: 
+  :local: 
 
 -------------------
 Configuration logic
@@ -184,6 +185,8 @@ nested inside another. In this case the parent condition is checked first and th
 Internals
 ^^^^^^^^^
 
+These classes should not be used directly.
+
 .. autoclass:: ConfigElem
   :members:
 
@@ -192,7 +195,11 @@ Internals
 
 
 ----------------------------------------
-Config parser module `moe.config_parser`
+Configuration parser
 ----------------------------------------
 
 .. automodule:: moe.config_parser
+
+.. autoclass:: ConfigSyntaxError
+
+.. autofunction:: config_escape
diff --git a/t/moe/config_parser.py b/t/moe/config_parser.py
index b3131cc..838d76b 100644
--- a/t/moe/config_parser.py
+++ b/t/moe/config_parser.py
@@ -47,6 +47,16 @@ import traceback
 import moe.config as cf
 
 
+def config_escape(s):
+  """
+  Escape any ``{``, ``}``, ``"`` and ``\\`` in the given string, making it safe for parsing.
+  """
+  s = s.replace('\\', '\\\\')
+  s = s.replace('{', '\\{')
+  s = s.replace('}', '\\}')
+  s = s.replace('"', '\\"')
+  return s
+
 class ConfigSyntaxError(cf.ConfigError):
 
   def __init__(self, msg, source='<unknown>', line=None, column=None):
diff --git a/t/moe/config_test.py b/t/moe/config_test.py
index f1c836d..d6eb51b 100644
--- a/t/moe/config_test.py
+++ b/t/moe/config_test.py
@@ -106,6 +106,10 @@ class TestParser(TestConfig):
     for v in 'abcd':
       assert len(s.var(v).operations) == 0
 
+  def test_escape(s):
+    for tst in ['{B}"#\n\\"', '', '\\\n\\\\"\\{\\}', '"#"', s.s1, s.s2]:
+      s.parse('A="%s"; A+="0"'%config_escape(tst))
+      assert s.val('A') == tst+'0'
 
 class TestConfigEval(TestConfig):
 
-- 
2.39.2