Move under_transaction flag from mysqldb to database API.

git-svn-id: https://svn.erp5.org/repos/neo/trunk@1379 71dcc9de-d417-0410-9af5-da40c76e7ee4

neo/storage/database.py

@@ -16,13 +16,49 @@
 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 
 from neo import util
+from neo.exception import DatabaseFailure
 
 class DatabaseManager(object):
     """This class only describes an interface for database managers."""
 
     def __init__(self, **kwargs):
-        """Initialize the object."""
-        pass
+        """
+            Initialize the object.
+        """
+        self._under_transaction = False
+
+    def connect(self):
+        """
+            Establish the connection to the database
+        """
+        self._connect()
+        self._under_transaction = False
+
+    def begin(self):
+        """
+            Begin a transaction
+        """
+        if self._under_transaction:
+            raise DatabaseFailure('A transaction as already began')
+        self._begin()
+        self._under_transaction = True
+
+    def commit(self):
+        """
+            Commit the current transaction
+        """
+        if not self._under_transaction:
+            raise DatabaseFailure('The transaction as not began')
+        self._commit()
+        self._under_transaction = False
+
+    def rollback(self):
+        """
+            Rollback the current transaction
+        """
+        # XXX: don't care if not in a transaction ?
+        self._rollback()
+        self._under_transaction = False
 
     def setup(self, reset = 0):
         """Set up a database. If reset is true, existing data must be
@@ -33,6 +69,12 @@ class DatabaseManager(object):
         """ close the database connection """
         raise NotImplementedError
 
+    def _connect(self):
+        raise NotImplementedError
+
+    def _begin(self):
+        raise NotImplementedError
+
     def getConfiguration(self, key):
         """
             Return a configuration value, returns None if not found or not set

neo/storage/mysqldb.py

@@ -51,7 +51,7 @@ class MySQLDatabaseManager(DatabaseManager):
     def close(self):
         self.conn.close()
 
-    def connect(self):
+    def _connect(self):
         kwd = {'db' : self.db, 'user' : self.user}
         if self.passwd is not None:
             kwd['passwd'] = self.passwd
@@ -59,25 +59,15 @@ class MySQLDatabaseManager(DatabaseManager):
                      self.db, self.user)
         self.conn = MySQLdb.connect(**kwd)
         self.conn.autocommit(False)
-        self.under_transaction = False
 
-    def begin(self):
-        if self.under_transaction:
-            try:
-                self.commit()
-            except:
-                # Ignore any error for this implicit commit.
-                pass
+    def _begin(self):
         self.query("""BEGIN""")
-        self.under_transaction = True
 
-    def commit(self):
+    def _commit(self):
         self.conn.commit()
-        self.under_transaction = False
 
-    def rollback(self):
+    def _rollback(self):
         self.conn.rollback()
-        self.under_transaction = False
 
     def query(self, query):
         """Query data from a database."""