Merge pull request #58 from zopefoundation/allow_None

Allow None as a special key (sorted smaller than all others).

BTrees/_base.py

@@ -22,7 +22,7 @@
 
 from .Interfaces import BTreesConflictError
 from ._compat import PY3
-from ._compat import cmp
+from ._compat import compare
 from ._compat import int_types
 from ._compat import xrange
 
@@ -113,7 +113,8 @@ def _search(self, key):
             k = keys[i]
             if k is key or k == key:
                 return i
-            if k < key:
+
+            if compare(k, key) < 0:
                 low = i + 1
             else:
                 high = i
@@ -256,7 +257,7 @@ def advance(self):
 def _no_default_comparison(key):
     # Enforce test that key has non-default comparison.
     if key is None:
-        raise TypeError("Can't use None as a key")
+        return
     if type(key) is object:
         raise TypeError("Can't use object() as keys")
     lt = getattr(key, '__lt__', None)
@@ -458,8 +459,8 @@ def merge_output(it):
             it.advance()
 
         while i_old.active and i_com.active and i_new.active:
-            cmpOC = cmp(i_old.key, i_com.key)
-            cmpON = cmp(i_old.key, i_new.key)
+            cmpOC = compare(i_old.key, i_com.key)
+            cmpON = compare(i_old.key, i_new.key)
             if cmpOC == 0:
                 if cmpON == 0:
                     if i_com.value == i_old.value:
@@ -497,7 +498,7 @@ def merge_output(it):
                 else:
                     raise merge_error(3)
             else: # both keys changed
-                cmpCN = cmp(i_com.key, i_new.key)
+                cmpCN = compare(i_com.key, i_new.key)
                 if cmpCN == 0: # dueling insert
                     raise merge_error(4)
                 if cmpOC > 0: # insert committed
@@ -511,7 +512,7 @@ def merge_output(it):
                     raise merge_error(5) # both deleted same key
 
         while i_com.active and i_new.active: # new inserts
-            cmpCN = cmp(i_com.key, i_new.key)
+            cmpCN = compare(i_com.key, i_new.key)
             if cmpCN == 0:
                 raise merge_error(6) # dueling insert
             if cmpCN > 0: # insert new
@@ -520,7 +521,7 @@ def merge_output(it):
                 merge_output(i_com)
 
         while i_old.active and i_com.active: # new deletes rest of original
-            cmpOC = cmp(i_old.key, i_com.key)
+            cmpOC = compare(i_old.key, i_com.key)
             if cmpOC > 0: # insert committed
                 merge_output(i_com)
             elif cmpOC == 0 and (i_old.value == i_com.value): # del in new
@@ -531,7 +532,7 @@ def merge_output(it):
 
         while i_old.active and i_new.active:
             # committed deletes rest of original
-            cmpON = cmp(i_old.key, i_new.key)
+            cmpON = compare(i_old.key, i_new.key)
             if cmpON > 0: # insert new
                 merge_output(i_new)
             elif cmpON == 0 and (i_old.value == i_new.value):
@@ -665,8 +666,8 @@ def merge_output(it):
             it.advance()
 
         while i_old.active and i_com.active and i_new.active:
-            cmpOC = cmp(i_old.key, i_com.key)
-            cmpON = cmp(i_old.key, i_new.key)
+            cmpOC = compare(i_old.key, i_com.key)
+            cmpON = compare(i_old.key, i_new.key)
             if cmpOC == 0:
                 if cmpON == 0: # all match
                     merge_output(i_old)
@@ -694,7 +695,7 @@ def merge_output(it):
                     i_old.advance()
                     i_new.advance()
             else: # both com and new keys changed
-                cmpCN = cmp(i_com.key, i_new.key)
+                cmpCN = compare(i_com.key, i_new.key)
                 if cmpCN == 0: # both inserted same key
                     raise merge_error(4)
                 if cmpOC > 0: # insert committed
@@ -708,7 +709,7 @@ def merge_output(it):
                     raise merge_error(5)
 
         while i_com.active and i_new.active: # new inserts
-            cmpCN = cmp(i_com.key, i_new.key)
+            cmpCN = compare(i_com.key, i_new.key)
             if cmpCN == 0: # dueling insert
                 raise merge_error(6)
             if cmpCN > 0: # insert new
@@ -717,7 +718,7 @@ def merge_output(it):
                 merge_output(i_com)
 
         while i_old.active and i_com.active: # new deletes rest of original
-            cmpOC = cmp(i_old.key, i_com.key)
+            cmpOC = compare(i_old.key, i_com.key)
             if cmpOC > 0: # insert committed
                 merge_output(i_com)
             elif cmpOC == 0: # del in new
@@ -728,7 +729,7 @@ def merge_output(it):
 
         while i_old.active and i_new.active:
             # committed deletes rest of original
-            cmpON = cmp(i_old.key, i_new.key)
+            cmpON = compare(i_old.key, i_new.key)
             if cmpON > 0: # insert new
                 merge_output(i_new)
             elif cmpON == 0: # deleted in committed
@@ -843,7 +844,7 @@ def _search(self, key):
             hi = len(data)
             i = hi // 2
             while i > lo:
-                cmp_ = cmp(data[i].key, key)
+                cmp_ = compare(data[i].key, key)
                 if cmp_ < 0:
                     lo = i
                 elif cmp_ > 0:
@@ -919,7 +920,7 @@ def maxKey(self, max=_marker):
 
         max = self._to_key(max)
         index = self._search(max)
-        if index and data[index].child.minKey() > max:
+        if index and compare(data[index].child.minKey(), max) > 0:
             index -= 1 #pragma: no cover  no idea how to provoke this
         return data[index].child.maxKey(max)
 
@@ -1014,7 +1015,7 @@ def _del(self, key):
             self._p_changed = True
 
         # fix up the node key, but not for the 0'th one.
-        if index > 0 and child.size and key == data[index].key:
+        if index > 0 and child.size and compare(key, data[index].key) == 0:
             self._p_changed = True
             data[index].key = child.minKey()
 
@@ -1324,7 +1325,7 @@ def copy(i):
         def copy(i):
             result._keys.append(i.key)
     while i1.active and i2.active:
-        cmp_ = cmp(i1.key, i2.key)
+        cmp_ = compare(i1.key, i2.key)
         if cmp_ < 0:
             copy(i1)
             i1.advance()
@@ -1349,7 +1350,7 @@ def union(set_type, o1, o2):
     def copy(i):
         result._keys.append(i.key)
     while i1.active and i2.active:
-        cmp_ = cmp(i1.key, i2.key)
+        cmp_ = compare(i1.key, i2.key)
         if cmp_ < 0:
             copy(i1)
             i1.advance()
@@ -1379,7 +1380,7 @@ def intersection(set_type, o1, o2):
     def copy(i):
         result._keys.append(i.key)
     while i1.active and i2.active:
-        cmp_ = cmp(i1.key, i2.key)
+        cmp_ = compare(i1.key, i2.key)
         if cmp_ < 0:
             i1.advance()
         elif cmp_ == 0:
@@ -1425,7 +1426,7 @@ def copy(i, w):
             result._keys.append(i.key)
 
     while i1.active and i2.active:
-        cmp_ = cmp(i1.key, i2.key)
+        cmp_ = compare(i1.key, i2.key)
         if cmp_ < 0:
             copy(i1, w1)
             i1.advance()
@@ -1466,7 +1467,7 @@ def weightedIntersection(set_type, o1, o2, w1=1, w2=1):
     else:
         result = o1._set_type()
     while i1.active and i2.active:
-        cmp_ = cmp(i1.key, i2.key)
+        cmp_ = compare(i1.key, i2.key)
         if cmp_ < 0:
             i1.advance()
         elif cmp_ == 0:

BTrees/_compat.h

@@ -33,8 +33,9 @@
   -1 -> There was an error, which the caller will detect with PyError_Occurred.
  */
 #define COMPARE(lhs, rhs) \
-  PyObject_RichCompareBool((lhs), (rhs), Py_LT) != 0 ? -1 : \
-    (PyObject_RichCompareBool((lhs), (rhs), Py_EQ) > 0 ? 0 : 1)
+  (lhs == Py_None ? (rhs == Py_None ? 0 : -1) : (rhs == Py_None ? 1 : \
+     (PyObject_RichCompareBool((lhs), (rhs), Py_LT) != 0 ? -1 : \
+      (PyObject_RichCompareBool((lhs), (rhs), Py_EQ) > 0 ? 0 : 1))))
 
 #else
 
@@ -45,7 +46,9 @@
 #define TEXT_FROM_STRING PyString_FromString
 #define TEXT_FORMAT PyString_Format
 
-#define COMPARE(lhs, rhs) PyObject_Compare((lhs), (rhs))
+#define COMPARE(lhs, rhs) \
+  (lhs == Py_None ? (rhs == Py_None ? 0 : -1) : (rhs == Py_None ? 1 : \
+     PyObject_Compare((lhs), (rhs))))
 
 #endif
 

BTrees/_compat.py

@@ -23,7 +23,16 @@
 
     int_types = int, long
     xrange = xrange
-    cmp = cmp
+    def compare(x, y):
+        if x is None:
+            if y is None:
+                return 0
+            else:
+                return -1
+        elif y is None:
+            return 1
+        else:
+            return cmp(x, y)
 
     _bytes = str
     def _ascii(x):
@@ -43,8 +52,16 @@ def _u(s, encoding='unicode_escape'):
     int_types = int,
     xrange = range
 
-    def cmp(x, y):
-        return (x > y) - (y > x)
+    def compare(x, y):
+        if x is None:
+            if y is None:
+                return 0
+            else:
+                return -1
+        elif y is None:
+            return 1
+        else:
+            return (x > y) - (y > x)
 
     _bytes = bytes
     def _ascii(x):

BTrees/check.py

@@ -56,6 +56,8 @@
 
 TYPE_UNKNOWN, TYPE_BTREE, TYPE_BUCKET = range(3)
 
+from ._compat import compare
+
 _type2kind = {}
 for kv in ('OO',
            'II', 'IO', 'OI', 'IF',
@@ -346,13 +348,15 @@ def visit_bucket(self, obj, path, parent, is_mapping,
     def check_sorted(self, obj, path, keys, lo, hi):
         i, n = 0, len(keys)
         for x in keys:
-            if lo is not None and not lo <= x:
+            # lo or hi are ommitted by supplying None. Thus the not
+            # None checkes below.
+            if lo is not None and not compare(lo, x) <= 0:
                 s = "key %r < lower bound %r at index %d" % (x, lo, i)
                 self.complain(s, obj, path)
-            if hi is not None and not x < hi:
+            if hi is not None and not compare(x, hi) < 0:
                 s = "key %r >= upper bound %r at index %d" % (x, hi, i)
                 self.complain(s, obj, path)
-            if i < n-1 and not x < keys[i+1]:
+            if i < n-1 and not compare(x, keys[i+1]) < 0:
                 s = "key %r at index %d >= key %r at index %d" % (
                     x, i, keys[i+1], i+1)
                 self.complain(s, obj, path)

BTrees/objectkeymacros.h

@@ -15,6 +15,9 @@ check_argument_cmp(PyObject *arg)
     /*        ((PyTypeObject *)object_)->ob_type->tp_richcompare, */
     /*        arg->ob_type->tp_compare, */
     /*        ((PyTypeObject *)object_)->ob_type->tp_compare); */
+    if (arg == Py_None) {
+      return 1;
+    }
 
 #ifdef PY3K
     if (Py_TYPE(arg)->tp_richcompare == Py_TYPE(object_)->tp_richcompare)

BTrees/tests/test_OOBTree.py

@@ -161,6 +161,32 @@ class C(object):
         self.assertRaises(KeyError, t.__getitem__, C())
         self.assertFalse(C() in t)
 
+    def test_None_is_smallest(self):
+        t = self._makeOne()
+        for i in range(999): # Make sure we multiple buckets
+            t[i] = i*i
+        t[None] = -1
+        for i in range(-99,0): # Make sure we multiple buckets
+            t[i] = i*i
+        self.assertEqual(list(t), [None] + list(range(-99, 999)))
+        self.assertEqual(list(t.values()),
+                         [-1] + [i*i for i in range(-99, 999)])
+        self.assertEqual(t[2], 4)
+        self.assertEqual(t[-2], 4)
+        self.assertEqual(t[None], -1)
+        t[None] = -2
+        self.assertEqual(t[None], -2)
+        t2 = t.__class__(t)
+        del t[None]
+        self.assertEqual(list(t), list(range(-99, 999)))
+
+        if 'Py' in self.__class__.__name__:
+            return
+        from BTrees.OOBTree import difference, union, intersection
+        self.assertEqual(list(difference(t2, t).items()), [(None, -2)])
+        self.assertEqual(list(union(t, t2)), list(t2))
+        self.assertEqual(list(intersection(t, t2)), list(t))
+
     @_skip_under_Py3k
     def testDeleteNoneKey(self):
         # Check that a None key can be deleted in Python 2.

CHANGES.rst

@@ -1,6 +1,8 @@
 ``BTrees`` Changelog
 ====================
 
+- Allow None as a special key (sorted smaller than all others).
+
 4.3.2 (2017-01-05)
 ------------------