Clean up comments when rendering nftables ACLs in Capirca

- Newlines replaced with spaces instead of just removed
- Change double quotes to single quotes within comments, rather than escape doubles inside doubles
- Sanity check for maximum length

PiperOrigin-RevId: 618279002

capirca/lib/aclgenerator.py

@@ -610,13 +610,15 @@ def TruncateWords(input_text, char_limit):
   Returns:
     truncated single string element within double quotes.
   """
-  CHAR_LIMIT = 126
+  hard_limit = 126
+  if char_limit > hard_limit:
+    char_limit = hard_limit
 
   if isinstance(input_text, list):
-    # handle multiple comments. Remove newline.
+    # Handle multiple comments. Newline to space and double to single quotes.
     sanitized_list = []
     for i in input_text:
-      sanitized_list.append(i.replace('\n', ''))
+      sanitized_list.append(i.replace('\n', ' ').replace('\"', '\''))
     comment = ' '.join(sanitized_list)
   else:
     comment = input_text

tests/lib/aclgenerator_test.py

@@ -99,7 +99,7 @@ def setUp(self):
       'There is something very long about this comment that',
       'will require it to be truncated in order for nftables',
       'binary to be able to load the rulesets.'], '"There is something very long about this comment that will require it to be truncated in order for nftables binary to be able t"'),
-    (['some comment description', 'second comment item \nNewline'], '"some comment description second comment item Newline"'), ('a string comment', '"a string comment"'))
+    (['some "comment" description', 'second \'comment\' item\nNewline'], '"some \'comment\' description second \'comment\' item Newline"'), ('a string comment', '"a string comment"'))
   def testTruncateWords(self, input_data, expected_output):
     result = aclgenerator.TruncateWords(
         input_data, 126)