Removed CollectionManager, moved work to QuerySet

As CollectionManager has been replaced with QuerySet and
QuerySetManager, collection.py has been renamed queryset.py.

mongoengine/queryset.py

@@ -0,0 +1,118 @@
+from connection import _get_db
+
+import pymongo
+
+
+class QuerySet(object):
+    """A set of results returned from a query. Wraps a MongoDB cursor, 
+    providing Document objects as the results.
+    """
+    
+    def __init__(self, document, collection):
+        self._document = document
+        self._collection = collection
+        self._query = {'_types': self._document._class_name}
+        self._cursor_obj = None
+
+    def __call__(self, **query):
+        """Filter the selected documents by calling the queryset with a query.
+        """
+        self._query.update(QuerySet._transform_query(**query))
+        return self
+
+    @property
+    def _cursor(self):
+        if not self._cursor_obj:
+            self._cursor_obj = self._collection.find(self._query)
+        return self._cursor_obj
+       
+    @classmethod
+    def _transform_query(cls, **query):
+        """Transform a query from Django-style format to Mongo format.
+        """
+        operators = ['neq', 'gt', 'gte', 'lt', 'lte', 'in', 'nin', 'mod',
+                     'all', 'size', 'exists']
+
+        mongo_query = {}
+        for key, value in query.items():
+            parts = key.split('__')
+            # Check for an operator and transform to mongo-style if there is
+            if parts[-1] in operators:
+                op = parts.pop()
+                value = {'$' + op: value}
+
+            key = '.'.join(parts)
+            mongo_query[key] = value
+
+        return mongo_query
+
+    def first(self):
+        """Retrieve the first object matching the query.
+        """
+        result = self._collection.find_one(self._query)
+        if result is not None:
+            result = self._document._from_son(result)
+        return result
+
+    def with_id(self, object_id):
+        """Retrieve the object matching the _id provided.
+        """
+        if not isinstance(object_id, pymongo.objectid.ObjectId):
+            object_id = pymongo.objectid.ObjectId(object_id)
+
+        result = self._collection.find_one(object_id)
+        if result is not None:
+            result = self._document._from_son(result)
+        return result
+
+    def next(self):
+        """Wrap the result in a Document object.
+        """
+        return self._document._from_son(self._cursor.next())
+
+    def count(self):
+        """Count the selected elements in the query.
+        """
+        return self._cursor.count()
+
+    def limit(self, n):
+        """Limit the number of returned documents to.
+        """
+        self._cursor.limit(n)
+        # Return self to allow chaining
+        return self
+
+    def skip(self, n):
+        """Skip n documents before returning the results.
+        """
+        self._cursor.skip(n)
+        return self
+
+    def delete(self):
+        """Delete the documents matched by the query.
+        """
+        self._collection.remove(self._query)
+
+    def __iter__(self):
+        return self
+
+
+class QuerySetManager(object):
+
+    def __init__(self, document):
+        db = _get_db()
+        self._document = document
+        self._collection_name = document._meta['collection']
+        # This will create the collection if it doesn't exist
+        self._collection = db[self._collection_name]
+
+    def __get__(self, instance, owner):
+        """Descriptor for instantiating a new QuerySet object when 
+        Document.objects is accessed.
+        """
+        if instance is not None:
+            # Document class being used rather than a document object
+            return self
+        
+        # self._document should be the same as owner
+        return QuerySet(self._document, self._collection)