Fixed bug in RealDictCursor when prefetching

ChangeLog

@@ -1,5 +1,8 @@
 2009-05-10  Federico Di Gregorio  <fog@initd.org>
 
+	* lib/extras.py: fixed crash in fetchone() when prefetching using
+	a RealDictCursor.
+
 	* psycopg/cursor_ext.c: now raise correct exception when fetching
 	using a custom row factory results in an error.
 

lib/extras.py

@@ -45,32 +45,47 @@ class DictCursorBase(_cursor):
                 "DictCursorBase can't be instantiated without a row factory.")
         _cursor.__init__(self, *args, **kwargs)
         self._query_executed = 0
+        self._prefetch = 0
         self.row_factory = row_factory
 
     def fetchone(self):
-        res = _cursor.fetchone(self)
+        if self._prefetch:
+            res = _cursor.fetchone(self)
         if self._query_executed:
             self._build_index()
+        if not self._prefetch:
+            res = _cursor.fetchone(self)
         return res
 
     def fetchmany(self, size=None):
-        res = _cursor.fetchmany(self, size)
+        if self._prefetch:
+            res = _cursor.fetchmany(self, size)
         if self._query_executed:
             self._build_index()
+        if not self._prefetch:
+            res = _cursor.fetchmany(self, size)
         return res
 
     def fetchall(self):
-        res = _cursor.fetchall(self)
+        if self._prefetch:
+            res = _cursor.fetchall(self)
         if self._query_executed:
             self._build_index()
+        if not self._prefetch:
+            res = _cursor.fetchall(self)
         return res
 
     def next(self):
-        res = _cursor.fetchone(self)
-        if res is None:
-            raise StopIteration()
+        if self._prefetch:
+            res = _cursor.fetchone(self)
+            if res is None:
+                raise StopIteration()
         if self._query_executed:
             self._build_index()
+        if not self._prefetch:
+            res = _cursor.fetchone(self)
+            if res is None:
+                raise StopIteration()
         return res
 
 class DictConnection(_connection):
@@ -87,6 +102,7 @@ class DictCursor(DictCursorBase):
     def __init__(self, *args, **kwargs):
         kwargs['row_factory'] = DictRow
         DictCursorBase.__init__(self, *args, **kwargs)
+        self._prefetch = 1
 
     def execute(self, query, vars=None, async=0):
         self.index = {}
@@ -175,6 +191,7 @@ class RealDictCursor(DictCursorBase):
     def __init__(self, *args, **kwargs):
         kwargs['row_factory'] = RealDictRow
         DictCursorBase.__init__(self, *args, **kwargs)
+        self._prefetch = 0
 
     def execute(self, query, vars=None, async=0):
         self.column_mapping = []
@@ -188,20 +205,20 @@ class RealDictCursor(DictCursorBase):
 
     def _build_index(self):
         if self._query_executed == 1 and self.description:
-            for item in self.description:
-                self.column_mapping.append(item[0])
+            for i in range(len(self.description)):
+                self.column_mapping.append(self.description[i][0])
             self._query_executed = 0
 
 class RealDictRow(dict):
 
-    __slots__ = ('_column_mapping',)
+    __slots__ = ('_column_mapping')
 
     def __init__(self, cursor):
         dict.__init__(self)
         self._column_mapping = cursor.column_mapping
 
     def __setitem__(self, name, value):
-        if type(name) == type(0):
+        if type(name) == int:
             name = self._column_mapping[name]
         return dict.__setitem__(self, name, value)
 

setup.py

@@ -222,7 +222,7 @@ class psycopg_build_ext(build_ext):
 
             define_macros.append(("PG_VERSION_HEX", "0x%02X%02X%02X" %
                                   (int(pgmajor), int(pgminor), int(pgpatch))))
-        except (Warning, w):
+        except Warning, w:
             if self.pg_config == self.DEFAULT_PG_CONFIG:
                 sys.stderr.write("Warning: %s" % str(w))
             else:

tests/extras_dictcursor.py

@@ -48,6 +48,21 @@ class ExtrasDictCursorTests(unittest.TestCase):
                 return row
         self._testWithPlainCursor(getter)
 
+    def testDictCursorWithPlainCursorRealFetchOne(self):
+        self._testWithPlainCursorReal(lambda curs: curs.fetchone())
+
+    def testDictCursorWithPlainCursorRealFetchMany(self):
+        self._testWithPlainCursorReal(lambda curs: curs.fetchmany(100)[0])
+
+    def testDictCursorWithPlainCursorRealFetchAll(self):
+        self._testWithPlainCursorReal(lambda curs: curs.fetchall()[0])
+
+    def testDictCursorWithPlainCursorRealIter(self):
+        def getter(curs):
+            for row in curs:
+                return row
+        self._testWithPlainCursorReal(getter)
+
     def testDictCursorWithNamedCursorFetchOne(self):
         self._testWithNamedCursor(lambda curs: curs.fetchone())
 
@@ -77,6 +92,18 @@ class ExtrasDictCursorTests(unittest.TestCase):
         self.failUnless(row['foo'] == 'bar')
         self.failUnless(row[0] == 'bar')
 
+    def _testWithPlainCursorReal(self, getter):
+        curs = self.conn.cursor(cursor_factory=psycopg2.extras.RealDictCursor)
+        curs.execute("SELECT * FROM ExtrasDictCursorTests")
+        row = getter(curs)
+        self.failUnless(row['foo'] == 'bar')
+
+    def _testWithNamedCursorReal(self, getter):
+        curs = self.conn.cursor('aname', cursor_factory=psycopg2.extras.RealDictCursor)
+        curs.execute("SELECT * FROM ExtrasDictCursorTests")
+        row = getter(curs)
+        self.failUnless(row['foo'] == 'bar')
+
 def test_suite():
     return unittest.TestLoader().loadTestsFromName(__name__)