implement cython for cache_anon_map, prefix_anon_map

These are small bits where cache_anon_map in particular
is part of the cache key generation scheme which is a key
target for cython.

changing such a tiny element of the cache key gen is
doing basically nothing yet, as the cython impl is
mostly the exact same speed as the python one.  I guess for
cython to be effective we'd need to redo the whole cache key
generation and possibly not use the same kinds of structures,
which might not be very easy to do.

Additionally, some cython runtime import errors are being
observed on jenkins, add an upfront check to the test suite
to indicate if the expected build succeeded when REQUIRE_SQLALCHEMY_CEXT
is set.

Running case CacheAnonMap
Running python .... Done
Running cython .... Done
                    | python      | cython      | cy / py     |
test_get_anon_non_present| 0.301266758 | 0.231203834 | 0.767438915 |
test_get_anon_present| 0.300919362 | 0.227336695 | 0.755473803 |
test_has_key_non_present| 0.152725077 | 0.133191719 | 0.872101171 |
test_has_key_present| 0.152689778 | 0.133673095 | 0.875455428 |
Running case PrefixAnonMap
Running python .. Done
Running cython .. Done
                    | python      | cython      | cy / py     |
test_apply_non_present| 0.358715744 | 0.335245703 | 0.934572034 |
test_apply_present  | 0.354434996 | 0.338579782 | 0.955266229 |

Change-Id: I0d3f1dd285c044afc234479141d831b2ee0455be

1 files changed, 9 insertions, 29 deletions

diff --git a/lib/sqlalchemy/sql/traversals.py b/lib/sqlalchemy/sql/traversals.py
index d58b5c2bb..22398e7c1 100644
--- a/lib/sqlalchemy/sql/traversals.py
+++ b/lib/sqlalchemy/sql/traversals.py
@@ -12,6 +12,12 @@ from .. import util
 from ..inspection import inspect
 from ..util import HasMemoized
 
+try:
+    from sqlalchemy.cyextension.util import cache_anon_map as anon_map  # noqa
+except ImportError:
+    from ._py_util import cache_anon_map as anon_map  # noqa
+
+
 SKIP_TRAVERSE = util.symbol("skip_traverse")
 COMPARE_FAILED = False
 COMPARE_SUCCEEDED = True
@@ -177,16 +183,11 @@ class HasCacheKey:
 
         """
 
-        idself = id(self)
         cls = self.__class__
 
-        if idself in anon_map:
-            return (anon_map[idself], cls)
-        else:
-            # inline of
-            # id_ = anon_map[idself]
-            anon_map[idself] = id_ = str(anon_map.index)
-            anon_map.index += 1
+        id_, found = anon_map.get_anon(self)
+        if found:
+            return (id_, cls)
 
         try:
             dispatcher = cls.__dict__["_generated_cache_key_traversal"]
@@ -1030,27 +1031,6 @@ def _resolve_name_for_compare(element, name, anon_map, **kw):
     return name
 
 
-class anon_map(dict):
-    """A map that creates new keys for missing key access.
-
-    Produces an incrementing sequence given a series of unique keys.
-
-    This is similar to the compiler prefix_anon_map class although simpler.
-
-    Inlines the approach taken by :class:`sqlalchemy.util.PopulateDict` which
-    is otherwise usually used for this type of operation.
-
-    """
-
-    def __init__(self):
-        self.index = 0
-
-    def __missing__(self, key):
-        self[key] = val = str(self.index)
-        self.index += 1
-        return val
-
-
 class TraversalComparatorStrategy(InternalTraversal, util.MemoizedSlots):
     __slots__ = "stack", "cache", "anon_map"