Remove submodule, just put Dependencies in ./libs

libs/migrate/changeset/databases/visitor.py

@@ -0,0 +1,78 @@
+"""
+   Module for visitor class mapping.
+"""
+import sqlalchemy as sa
+
+from migrate.changeset import ansisql
+from migrate.changeset.databases import (sqlite,
+                                         postgres,
+                                         mysql,
+                                         oracle,
+                                         firebird)
+
+
+# Map SA dialects to the corresponding Migrate extensions
+DIALECTS = {
+    "default": ansisql.ANSIDialect,
+    "sqlite": sqlite.SQLiteDialect,
+    "postgres": postgres.PGDialect,
+    "postgresql": postgres.PGDialect,
+    "mysql": mysql.MySQLDialect,
+    "oracle": oracle.OracleDialect,
+    "firebird": firebird.FBDialect,
+}
+
+
+def get_engine_visitor(engine, name):
+    """
+    Get the visitor implementation for the given database engine.
+
+    :param engine: SQLAlchemy Engine
+    :param name: Name of the visitor
+    :type name: string
+    :type engine: Engine
+    :returns: visitor
+    """
+    # TODO: link to supported visitors
+    return get_dialect_visitor(engine.dialect, name)
+
+
+def get_dialect_visitor(sa_dialect, name):
+    """
+    Get the visitor implementation for the given dialect.
+
+    Finds the visitor implementation based on the dialect class and
+    returns and instance initialized with the given name.
+
+    Binds dialect specific preparer to visitor.
+    """
+
+    # map sa dialect to migrate dialect and return visitor
+    sa_dialect_name = getattr(sa_dialect, 'name', 'default')
+    migrate_dialect_cls = DIALECTS[sa_dialect_name]
+    visitor = getattr(migrate_dialect_cls, name)
+
+    # bind preparer
+    visitor.preparer = sa_dialect.preparer(sa_dialect)
+
+    return visitor
+
+def run_single_visitor(engine, visitorcallable, element,
+    connection=None, **kwargs):
+    """Taken from :meth:`sqlalchemy.engine.base.Engine._run_single_visitor`
+    with support for migrate visitors.
+    """
+    if connection is None:
+        conn = engine.contextual_connect(close_with_result=False)
+    else:
+        conn = connection
+    visitor = visitorcallable(engine.dialect, conn)
+    try:
+        if hasattr(element, '__migrate_visit_name__'):
+            fn = getattr(visitor, 'visit_' + element.__migrate_visit_name__)
+        else:
+            fn = getattr(visitor, 'visit_' + element.__visit_name__)
+        fn(element, **kwargs)
+    finally:
+        if connection is None:
+            conn.close()