Python是否以错误的顺序删除了swip?可以修改吗?

Question

我使用swig将某些类包装在C 中。我的python脚本看起来像

#!/usr/bin/python
import pyinput
import pygeom
import pystate
import pyeqfactory
import pyeigenprobfactory
import pyeigensolver
inp = pyinput.Input("heter1d/1d1g_heter")
geo = pygeom.ProbGeom1D(inp)
state = pystate.State1D(inp, geo);
equation = pyeqfactory.EqFactory1D.New(state)
eigenprob = pyeigenprobfactory.EigenProbFactory1D.New(state, equation)
solver = pyeigensolver.EigenSolver1D(state, eigenprob)
solver.solve_eigenproblem()
print state.get_keff()

，我从智能指针类中遇到了一个错误，因为在仍然由其他

拥有的情况

--------------------------------------------------------
An error occurred in line <114> of file </home/segonpin/lib/dealii/source/base/subscriptor.cc> in function
    virtual dealii::Subscriptor::~Subscriptor()
The violated condition was: 
    counter == 0
The name and call sequence of the exception was:
    ExcInUse (counter, object_info->name(), infostring)
Additional Information: 
Object of class N6dealii13TriangulationILi1ELi1EEE is still used by 1 other objects.
(Additional information: <none>)
See the entry in the Frequently Asked Questions of deal.II (linked to from http://www.dealii.org/) for a lot more information on what this error means and how to fix programs in which it happens.
Stacktrace:
-----------
#0  /home/segonpin/lib/dealii-8.4.bin/lib/libdeal_II.g.so.8.4.2: dealii::Subscriptor::~Subscriptor()
#1  /home/segonpin/lib/dealii-8.4.bin/lib/libdeal_II.g.so.8.4.2: dealii::Triangulation<1, 1>::~Triangulation()
#2  /home/segonpin/codessebas/dealii-neutron-transport/python/_pygeom.so: Forest::ProbGeom<1>::~ProbGeom()
#3  /home/segonpin/codessebas/dealii-neutron-transport/python/_pygeom.so: 
#4  python: PyObject_Call
#5  python: PyObject_CallFunctionObjArgs
#6  /home/segonpin/codessebas/dealii-neutron-transport/python/_pygeom.so: 
#7  python: ) [0x4fd4e6]
#8  python: PyDict_SetItem
#9  python: _PyModule_Clear
#10  python: PyImport_Cleanup
#11  python: Py_Finalize
#12  python: Py_Main
#13  /lib/x86_64-linux-gnu/libc.so.6: __libc_start_main
#14  python: _start
--------------------------------------------------------

当我手动删除以正确顺序生成问题的两个类时，错误消失了

#!/usr/bin/python
import pyinput
import pygeom
import pystate
import pyeqfactory
import pyeigenprobfactory
import pyeigensolver
inp = pyinput.Input("heter1d/1d1g_heter")
geo = pygeom.ProbGeom1D(inp)
state = pystate.State1D(inp, geo);
equation = pyeqfactory.EqFactory1D.New(state)
eigenprob = pyeigenprobfactory.EigenProbFactory1D.New(state, equation)
solver = pyeigensolver.EigenSolver1D(state, eigenprob)
solver.solve_eigenproblem()
print state.get_keff()
# these two lines solve the problem
del state
del geo

不应该以相同的顺序删除这些实例（因为geo在state的构造函数中使用）？谢谢！

---

编辑2017年2月15日，11:19。

我可以添加一些额外的理由，说明为什么我需要按特定顺序删除。我正在使用swig来解析c 库（www.dealii.org），当我创建一个需要a实例的B实例时，就会增加一个计数器。这用于删除对象（B需要a存在，因此我们在删除a之前删除b）。如果您以其他方式这样做，则会遇到错误。在这种情况下，Python实例包含其中一些依赖项，因此我必须在特定其他方面删除对象，以避免错误消息。

我在Python Destructor

中添加了一些消息

#!/usr/bin/python
import pyinput
import pygeom
import pystate
import pyeqfactory
import pyeigenprobfactory
import pyeigensolver
def deltalk(self):
  print type(self).__name__ ," die"
pyinput.Input.__del__ = deltalk
pygeom.ProbGeom1D.__del__ = deltalk
pystate.State1D.__del__ = deltalk
pyeqfactory.EqFactory1D.__del__ = deltalk
pyeigenprobfactory.EigenProbFactory1D.__del__ = deltalk
pyeigensolver.EigenSolver1D.__del__ = deltalk
pypostprocessing.PostProcessing1D.__del__ = deltalk
inp = pyinput.Input("heter1d/1d1g_heter")
geo = pygeom.ProbGeom1D(inp)
state = pystate.State1D(inp, geo);
equation = pyeqfactory.EqFactory1D.New(state)
eigenprob = pyeigenprobfactory.EigenProbFactory1D.New(state, equation)
solver = pyeigensolver.EigenSolver1D(state, eigenprob)

当我运行时，我发现它没有以我需要的方式破坏（在state之前销毁geo在C 中引起错误）

$ python test2_forest.py 
EigenSolver1D  die
ProbGeom1D  die
--------------------------------------------------------
An error occurred in line <114> of file </home/segonpin/lib/dealii/source/base/subscriptor.cc> in function
    virtual dealii::Subscriptor::~Subscriptor()
The violated condition was: 
    counter == 0
The name and call sequence of the exception was:
    ExcInUse (counter, object_info->name(), infostring)
Additional Information: 
Object of class N6dealii13TriangulationILi1ELi1EEE is still used by 1 other objects.
(Additional information: <none>)
See the entry in the Frequently Asked Questions of deal.II (linked to from http://www.dealii.org/) for a lot more information on what this error means and how to fix programs in which it happens.
Stacktrace:
-----------
#0  /home/segonpin/lib/dealii-8.4.bin/lib/libdeal_II.g.so.8.4.2: dealii::Subscriptor::~Subscriptor()
#1  /home/segonpin/lib/dealii-8.4.bin/lib/libdeal_II.g.so.8.4.2: dealii::Triangulation<1, 1>::~Triangulation()
#2  /home/segonpin/codessebas/dealii-neutron-transport/python/_pygeom.so: Forest::ProbGeom<1>::~ProbGeom()
#3  /home/segonpin/codessebas/dealii-neutron-transport/python/_pygeom.so: 
#4  python: PyObject_Call
#5  python: PyObject_CallFunctionObjArgs
#6  /home/segonpin/codessebas/dealii-neutron-transport/python/_pygeom.so: 
#7  python: ) [0x4fd4e6]
#8  python: PyDict_SetItem
#9  python: _PyModule_Clear
#10  python: PyImport_Cleanup
#11  python: Py_Finalize
#12  python: Py_Main
#13  /lib/x86_64-linux-gnu/libc.so.6: __libc_start_main
#14  python: _start

是否有一种通用方法告诉Python考虑考虑此依赖性的对象？还是我应该在每个班级的破坏者中明确说出来？

谢谢

Answer 1

如果有人在将来找到同样的问题，我找到了一种以我想要使用atexit的顺序调用删除的方法。

不干净，但功能解决方案

这不是很干净，但是我会这样：

#!/usr/bin/python
import pyinput
import pygeom
import pystate
import pyeqfactory
import pyeigenprobfactory
import pyeigensolver
def goodbye() :
  print "Goodbye!!n"
import atexit
atexit.register(goodbye)
def deltalk(self):
  print self.__class__.__name__ ," die"
pyinput.Input.__del__ = deltalk
pygeom.ProbGeom1D.__del__ = deltalk
pystate.State1D.__del__ = deltalk
pyeqfactory.Equation1D.__del__ = deltalk
pyeigenprobfactory.EigenProb1D.__del__ = deltalk
pyeigensolver.EigenSolver1D.__del__ = deltalk
pypostprocessing.PostProcessing1D.__del__ = deltalk
inp = pyinput.Input("heter1d/1d1g_heter")
atexit.register(inp.__del__)
geo = pygeom.ProbGeom1D(inp)
atexit.register(geo.__del__)
state = pystate.State1D(inp, geo);
atexit.register(state.__del__)
equation = pyeqfactory.EqFactory1D.New(state)
atexit.register(equation.__del__)
eigenprob = pyeigenprobfactory.EigenProbFactory1D.New(state, equation)
atexit.register(eigenprob.__del__)
solver = pyeigensolver.EigenSolver1D(state, eigenprob)
atexit.register(solver.__del__)

当我运行脚本时，我会得到

$ python test2_forest.py
EigenSolver1D  die
EigenProb1D  die
Equation1D  die
State1D  die
State1D  die
ProbGeom1D  die
Input  die
Goodbye!!
Input  die
EigenProb1D  die
State1D  die
ProbGeom1D  die
EigenSolver1D  die
Equation1D  die

更好的解决方案，如果您可以直接修改构造函数

，如果我只能在构造函数中添加 atexit.register，那就容易得多。

#!/usr/bin/python
import atexit
class Foo(object):
  def __init__(self, id):
    self.id = id
    atexit.register(self.__del__)
  def __del__(self):
    print(self.id, " says bye")
a = Foo(1)
b = Foo(2)
c = Foo(3)

但是这些类是在C 中定义的，并用SWIG解析，因此我需要修改现有类定义的构造函数才能这样做，因此对于短程序而言，它更容易进行。

。

修改现有构造函数...

如果您必须在许多课程中进行，这不是最好的选择，但是如果您仍然想避免手动注册。将类foo如下

#simplefoo.py
class Foo(object):
  def __init__(self, id):
    self.id = id

可以修改现有类的构造函数如下

#test.py
from simplefoo import Foo
# first: I load the module atexit and register the bye function    
import atexit
def bye():
  print("Bye bye!")
atexit.register(bye)
# second: I add the destructor that talks loudly
def del_ini(self):
  print(self.id, " says bye")
Foo.__del__ = del_ini 
# third: I modify the original constructor. This is ugly
Foo.ini_old = Foo.__init__
def ini_new(self, id):
  self.ini_old(id)
  atexit.register(self.__del__)
Foo.__init__ = ini_new
# fourth: I create objects and finish the program them to see what happens
a = Foo(1)
b = Foo(2)
c = Foo(3)

，当我们运行脚本时，我们得到

$ python3 test.py 
3  says bye
2  says bye
1  says bye
Bye bye!
3  says bye
1  says bye
2  says bye

谢谢。