Merged the queryset-refactor branch into trunk.

This is a big internal change, but mostly backwards compatible with existing
code. Also adds a couple of new features.

Fixed #245, #1050, #1656, #1801, #2076, #2091, #2150, #2253, #2306, #2400, #2430, #2482, #2496, #2676, #2737, #2874, #2902, #2939, #3037, #3141, #3288, #3440, #3592, #3739, #4088, #4260, #4289, #4306, #4358, #4464, #4510, #4858, #5012, #5020, #5261, #5295, #5321, #5324, #5325, #5555, #5707, #5796, #5817, #5987, #6018, #6074, #6088, #6154, #6177, #6180, #6203, #6658


git-svn-id: http://code.djangoproject.com/svn/django/trunk@7477 bcc190cf-cafb-0310-a4f2-bffc1f526a37

1 files changed, 50 insertions, 0 deletions

diff --git a/django/db/models/query_utils.py b/django/db/models/query_utils.py
new file mode 100644
index 0000000000..0ce7900c74
--- /dev/null
+++ b/django/db/models/query_utils.py
@@ -0,0 +1,50 @@
+"""
+Various data structures used in query construction.
+
+Factored out from django.db.models.query so that they can also be used by other
+modules without getting into circular import difficulties.
+"""
+
+from copy import deepcopy
+
+from django.utils import tree
+
+class QueryWrapper(object):
+    """
+    A type that indicates the contents are an SQL fragment and the associate
+    parameters. Can be used to pass opaque data to a where-clause, for example.
+    """
+    def __init__(self, sql, params):
+        self.data = sql, params
+
+class Q(tree.Node):
+    """
+    Encapsulates filters as objects that can then be combined logically (using
+    & and |).
+    """
+    # Connection types
+    AND = 'AND'
+    OR = 'OR'
+    default = AND
+
+    def __init__(self, *args, **kwargs):
+        super(Q, self).__init__(children=list(args) + kwargs.items())
+
+    def _combine(self, other, conn):
+        if not isinstance(other, Q):
+            raise TypeError(other)
+        obj = deepcopy(self)
+        obj.add(other, conn)
+        return obj
+
+    def __or__(self, other):
+        return self._combine(other, self.OR)
+
+    def __and__(self, other):
+        return self._combine(other, self.AND)
+
+    def __invert__(self):
+        obj = deepcopy(self)
+        obj.negate()
+        return obj
+