130 lines
4.7 KiB
Python
130 lines
4.7 KiB
Python
# Copyright 2015 The TensorFlow Authors. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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# ==============================================================================
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"""A simple stack that associates filename and line numbers with each object."""
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import inspect
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class TraceableObject(object):
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"""Wrap an object together with its the code definition location."""
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# Return codes for the set_filename_and_line_from_caller() method.
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SUCCESS, HEURISTIC_USED, FAILURE = (0, 1, 2)
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def __init__(self, obj, filename=None, lineno=None):
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self.obj = obj
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self.filename = filename
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self.lineno = lineno
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def set_filename_and_line_from_caller(self, offset=0):
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"""Set filename and line using the caller's stack frame.
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If the requested stack information is not available, a heuristic may
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be applied and self.HEURISTIC USED will be returned. If the heuristic
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fails then no change will be made to the filename and lineno members
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(None by default) and self.FAILURE will be returned.
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Args:
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offset: Integer. If 0, the caller's stack frame is used. If 1,
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the caller's caller's stack frame is used. Larger values are
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permissible but if out-of-range (larger than the number of stack
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frames available) the outermost stack frame will be used.
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Returns:
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TraceableObject.SUCCESS if appropriate stack information was found,
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TraceableObject.HEURISTIC_USED if the offset was larger than the stack,
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and TraceableObject.FAILURE if the stack was empty.
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"""
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retcode = self.SUCCESS
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frame = inspect.currentframe()
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# Offset is defined in "Args" as relative to the caller. We are one frame
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# beyond the caller.
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for _ in range(offset + 1):
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parent = frame.f_back
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if parent is None:
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# If the offset is too large then we use the largest offset possible.
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retcode = self.HEURISTIC_USED
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break
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frame = parent
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self.filename = frame.f_code.co_filename
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self.lineno = frame.f_lineno
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return retcode
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def copy_metadata(self):
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"""Return a TraceableObject like this one, but without the object."""
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return self.__class__(None, filename=self.filename, lineno=self.lineno)
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class TraceableStack(object):
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"""A stack of TraceableObjects."""
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def __init__(self, existing_stack=None):
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"""Constructor.
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Args:
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existing_stack: [TraceableObject, ...] If provided, this object will
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set its new stack to a SHALLOW COPY of existing_stack.
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"""
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self._stack = existing_stack[:] if existing_stack else []
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def push_obj(self, obj, offset=0):
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"""Add object to the stack and record its filename and line information.
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Args:
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obj: An object to store on the stack.
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offset: Integer. If 0, the caller's stack frame is used. If 1,
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the caller's caller's stack frame is used.
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Returns:
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TraceableObject.SUCCESS if appropriate stack information was found,
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TraceableObject.HEURISTIC_USED if the stack was smaller than expected,
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and TraceableObject.FAILURE if the stack was empty.
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"""
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traceable_obj = TraceableObject(obj)
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self._stack.append(traceable_obj)
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# Offset is defined in "Args" as relative to the caller. We are 1 frame
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# beyond the caller and need to compensate.
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return traceable_obj.set_filename_and_line_from_caller(offset + 1)
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def pop_obj(self):
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"""Remove last-inserted object and return it, without filename/line info."""
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return self._stack.pop().obj
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def peek_top_obj(self):
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"""Return the most recent stored object."""
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return self._stack[-1].obj
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def peek_objs(self):
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"""Return iterator over stored objects ordered newest to oldest."""
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return (t_obj.obj for t_obj in reversed(self._stack))
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def peek_traceable_objs(self):
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"""Return iterator over stored TraceableObjects ordered newest to oldest."""
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return reversed(self._stack)
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def __len__(self):
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"""Return number of items on the stack, and used for truth-value testing."""
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return len(self._stack)
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def copy(self):
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"""Return a copy of self referencing the same objects but in a new list.
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This method is implemented to support thread-local stacks.
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Returns:
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TraceableStack with a new list that holds existing objects.
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"""
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return TraceableStack(self._stack)
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