Merge pull request #109 from nctl144/lru_cache

[MRG+1] add lru_cache to css2xpath

parsel/csstranslator.py

@@ -1,8 +1,15 @@
+import six
+
+if six.PY2:
+    from functools32 import lru_cache
+else:
+    from functools import lru_cache
+
 from cssselect import GenericTranslator as OriginalGenericTranslator
 from cssselect import HTMLTranslator as OriginalHTMLTranslator
 from cssselect.xpath import XPathExpr as OriginalXPathExpr
 from cssselect.xpath import _unicode_safe_getattr, ExpressionError
-from cssselect.parser import FunctionalPseudoElement
+from cssselect.parser import parse, FunctionalPseudoElement
 
 
 class XPathExpr(OriginalXPathExpr):
@@ -91,11 +98,15 @@ def xpath_text_simple_pseudo_element(self, xpath):
 
 
 class GenericTranslator(TranslatorMixin, OriginalGenericTranslator):
-    pass
+    @lru_cache(maxsize=256)
+    def css_to_xpath(self, css, prefix='descendant-or-self::'):
+        return super(GenericTranslator, self).css_to_xpath(css, prefix)
 
 
 class HTMLTranslator(TranslatorMixin, OriginalHTMLTranslator):
-    pass
+    @lru_cache(maxsize=256)
+    def css_to_xpath(self, css, prefix='descendant-or-self::'):
+        return super(HTMLTranslator, self).css_to_xpath(css, prefix)
 
 
 _translator = HTMLTranslator()

setup.py

@@ -1,8 +1,10 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
 
+import sys
 
-from setuptools import setup
+from pkg_resources import parse_version
+from setuptools import setup, __version__ as setuptools_version
 
 
 with open('README.rst') as readme_file:
@@ -14,6 +16,29 @@
 test_requirements = [
 ]
 
+def has_environment_marker_platform_impl_support():
+    """Code extracted from 'pytest/setup.py'
+    https://github.com/pytest-dev/pytest/blob/7538680c/setup.py#L31
+    The first known release to support environment marker with range operators
+    it is 18.5, see:
+    https://setuptools.readthedocs.io/en/latest/history.html#id235
+    """
+    return parse_version(setuptools_version) >= parse_version('18.5')
+
+install_requires = [
+    'w3lib>=1.8.0',
+    'lxml>=2.3',
+    'six>=1.5.2',
+    'cssselect>=0.9'
+]
+extras_require = {}
+
+if not has_environment_marker_platform_impl_support():
+    if sys.version_info[0:2] < (3, 0):
+        install_requires.append("functools32")
+else:
+    extras_require[":python_version<'3.0'"] = ["functools32"]
+
 setup(
     name='parsel',
     version='1.4.0',
@@ -28,12 +53,8 @@
     package_dir={'parsel':
                  'parsel'},
     include_package_data=True,
-    install_requires=[
-        'w3lib>=1.8.0',
-        'lxml>=2.3',
-        'six>=1.5.2',
-        'cssselect>=0.9',
-    ],
+    install_requires=install_requires,
+    extras_require=extras_require,
     license="BSD",
     zip_safe=False,
     keywords='parsel',