Added psycopg2cffi dialect

3 files changed, 61 insertions, 4 deletions

diff --git a/lib/sqlalchemy/dialects/postgresql/__init__.py b/lib/sqlalchemy/dialects/postgresql/__init__.py
index 1cff8e3a0..01a846314 100644
--- a/lib/sqlalchemy/dialects/postgresql/__init__.py
+++ b/lib/sqlalchemy/dialects/postgresql/__init__.py
@@ -5,7 +5,7 @@
 # This module is part of SQLAlchemy and is released under
 # the MIT License: http://www.opensource.org/licenses/mit-license.php
 
-from . import base, psycopg2, pg8000, pypostgresql, zxjdbc
+from . import base, psycopg2, pg8000, pypostgresql, zxjdbc, psycopg2cffi
 
 base.dialect = psycopg2.dialect
 
diff --git a/lib/sqlalchemy/dialects/postgresql/psycopg2.py b/lib/sqlalchemy/dialects/postgresql/psycopg2.py
index fe27da8b6..5246abf1c 100644
--- a/lib/sqlalchemy/dialects/postgresql/psycopg2.py
+++ b/lib/sqlalchemy/dialects/postgresql/psycopg2.py
@@ -512,9 +512,19 @@ class PGDialect_psycopg2(PGDialect):
         import psycopg2
         return psycopg2
 
+    @classmethod
+    def _psycopg2_extensions(cls):
+        from psycopg2 import extensions
+        return extensions
+
+    @classmethod
+    def _psycopg2_extras(cls):
+        from psycopg2 import extras
+        return extras
+
     @util.memoized_property
     def _isolation_lookup(self):
-        from psycopg2 import extensions
+        extensions = self._psycopg2_extensions()
         return {
             'AUTOCOMMIT': extensions.ISOLATION_LEVEL_AUTOCOMMIT,
             'READ COMMITTED': extensions.ISOLATION_LEVEL_READ_COMMITTED,
@@ -536,7 +546,8 @@ class PGDialect_psycopg2(PGDialect):
         connection.set_isolation_level(level)
 
     def on_connect(self):
-        from psycopg2 import extras, extensions
+        extras = self._psycopg2_extras()
+        extensions = self._psycopg2_extensions()
 
         fns = []
         if self.client_encoding is not None:
@@ -586,7 +597,7 @@ class PGDialect_psycopg2(PGDialect):
     @util.memoized_instancemethod
     def _hstore_oids(self, conn):
         if self.psycopg2_version >= (2, 4):
-            from psycopg2 import extras
+            extras = self._psycopg2_extras()
             oids = extras.HstoreAdapter.get_oids(conn)
             if oids is not None and oids[0]:
                 return oids[0:2]
diff --git a/lib/sqlalchemy/dialects/postgresql/psycopg2cffi.py b/lib/sqlalchemy/dialects/postgresql/psycopg2cffi.py
new file mode 100644
index 000000000..5217c5561
--- /dev/null
+++ b/lib/sqlalchemy/dialects/postgresql/psycopg2cffi.py
@@ -0,0 +1,46 @@
+# testing/engines.py
+# Copyright (C) 2005-2014 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: http://www.opensource.org/licenses/mit-license.php
+"""
+.. dialect:: postgresql+psycopg2cffi
+    :name: psycopg2cffi
+    :dbapi: psycopg2cffi
+    :connectstring: \
+postgresql+psycopg2cffi://user:password@host:port/dbname\
+[?key=value&key=value...]
+    :url: http://pypi.python.org/pypi/psycopg2cffi/
+
+`psycopg2cffi` is an adaptation of `psycopg2`, using CFFI for the C
+layer. This makes it suitable for use in e.g. PyPy. Documentation
+is as per `psycopg2`.
+
+.. seealso::
+
+    :mod:`sqlalchemy.dialects.postgresql.psycopg2`
+
+"""
+from .psycopg2 import PGDialect_psycopg2
+
+
+class PGDialect_psycopg2cffi(PGDialect_psycopg2):
+    driver = 'psycopg2cffi'
+
+    @classmethod
+    def dbapi(cls):
+        return __import__('psycopg2cffi')
+
+    @classmethod
+    def _psycopg2_extensions(cls):
+        root = __import__('psycopg2cffi', fromlist=['extensions'])
+        return root.extensions
+
+    @classmethod
+    def _psycopg2_extras(cls):
+        root = __import__('psycopg2cffi', fromlist=['extras'])
+        return root.extras
+
+
+dialect = PGDialect_psycopg2cffi