chore: import upstream snapshot with attribution

python/paddle/base/default_scope_funcs.py

@@ -0,0 +1,95 @@
+#   Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""
+Default scope function.
+
+`Paddle` manages Scope as programming language's scope.  It just a
+thread-local stack of Scope. Top of that stack is current scope, the bottom
+of that stack is all scopes' parent.
+
+Invoking `var/find_var`  can `new/find` variable in current scope.
+Invoking `enter_local_scope/leave_local_scope` can create or destroy local
+scope.
+
+A `scoped_function` will take a `function` as input. That function will be
+invoked in a new local scope.
+"""
+
+import threading
+
+import paddle.base.core
+
+__tl_scope__ = threading.local()
+
+__all__ = []
+
+
+def get_cur_scope():
+    """
+    Get current scope.
+    :rtype: paddle.base.core.Scope
+    """
+    cur_scope_stack = getattr(__tl_scope__, 'cur_scope', None)
+    if cur_scope_stack is None:
+        __tl_scope__.cur_scope = []
+    if len(__tl_scope__.cur_scope) == 0:
+        __tl_scope__.cur_scope.append(paddle.base.core.Scope())
+    return __tl_scope__.cur_scope[-1]
+
+
+def enter_local_scope():
+    """
+    Enter a new local scope
+    """
+    cur_scope = get_cur_scope()
+    new_scope = cur_scope.new_scope()
+    __tl_scope__.cur_scope.append(new_scope)
+
+
+def leave_local_scope():
+    """
+    Leave local scope
+    """
+    __tl_scope__.cur_scope.pop()
+    get_cur_scope().drop_kids()
+
+
+def var(name):
+    """
+    create variable in current scope.
+    """
+    return get_cur_scope().var(name)
+
+
+def find_var(name):
+    """
+    get variable in current scope.
+    """
+    return get_cur_scope().find_var(name)
+
+
+def scoped_function(func):
+    """
+    invoke `func` in new scope.
+
+    :param func: a callable function that will be run in new scope.
+    :type func: callable
+    """
+    enter_local_scope()
+    try:
+        func()
+    except:
+        raise
+    finally:
+        leave_local_scope()