From 5187d5dc0239b15b190127aca8428759b78536ca Mon Sep 17 00:00:00 2001
From: Charles Haley <cbhaley@i.wont.say.com>
Date: Sat, 18 Apr 2020 18:33:09 +0100
Subject: [PATCH] Improve performance of rules templates by not calling the
 "and" function if there is only one condition.

---
 src/calibre/library/coloring.py | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/src/calibre/library/coloring.py b/src/calibre/library/coloring.py
index bd3b21f8b7..30240df8e6 100644
--- a/src/calibre/library/coloring.py
+++ b/src/calibre/library/coloring.py
@@ -62,14 +62,22 @@ class Rule(object):  # {{{
             return None
         conditions = [x for x in map(self.apply_condition, self.conditions) if x is not None]
         conditions = (',\n' + ' '*9).join(conditions)
-        return dedent('''\
-                program:
-                {sig}
-                test(and(
-                         {conditions}
-                    ), '{color}', '');
-                ''').format(sig=self.signature, conditions=conditions,
-                        color=self.color)
+        if len(self.conditions) > 1:
+            return dedent('''\
+                    program:
+                    {sig}
+                    test(and(
+                             {conditions}
+                        ), '{color}', '');
+                    ''').format(sig=self.signature, conditions=conditions,
+                            color=self.color)
+        else:
+            return dedent('''\
+                    program:
+                    {sig}
+                    test({conditions}, '{color}', '');
+                    ''').format(sig=self.signature, conditions=conditions,
+                            color=self.color)
 
     def apply_condition(self, condition):
         col, action, val = condition