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193 lines
12 KiB
Plaintext
193 lines
12 KiB
Plaintext
Given a real Python class 'A', a wrapped C++ class 'B', and this definition:
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class C(A, B):
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def __init__(self):
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B.__init__(self)
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self.x = 1
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...
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c = C()
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this diagram describes the internal structure of an instance of 'C', including
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its inheritance relationships. Note that ExtensionClass<B> is derived from
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Class<ExtensionInstance>, and is in fact identical for all intents and purposes.
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MetaClass<ExtensionInstance>
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+---------+ +---------+
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types.ClassType: | | | |
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| | | |
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| | | |
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+---------+ +---------+
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^ ^ ^
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PyClassObject | ExtensionClass<B> | |
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A: +------------+ | B: +------------+ | |
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| ob_type -+-+ | ob_type -+-----+ |
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| | ()<--+- __bases__ | |
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| | | __dict__ -+->{...} |
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| | 'B'<-+- __name__ | |
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+------------+ +------------+ |
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^ ^ |
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| | |
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+-----+ +-------------+ |
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| | |
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| | Class<ExtensionInstance> |
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| | C: +------------+ |
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| | | ob_type -+------------+
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tuple:(*, *)<--+- __bases__ |
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| __dict__ -+->{__module__, <methods, etc.>}
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'C' <-+- __name__ |
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+------------+
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^ (in case of inheritance from more than one
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| extension class, this vector would contain
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+---------------+ a pointer to an instance holder for the data
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| of each corresponding C++ class)
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| ExtensionInstance
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| c: +---------------------+ std::vector<InstanceHolderBase>
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+----+- __class__ | +---+--
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| m_wrapped_objects -+->| * | ...
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{'x': 1}<-+- __dict__ | +-|-+--
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+---------------------+ | InstanceValueHolder<B>
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| +--------------------------------+
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+-->| (contains a C++ instance of B) |
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+--------------------------------+
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In our inheritance test cases in extclass_demo.cpp/test_extclass.py, we have the
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following C++ inheritance hierarchy:
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+-----+ +----+
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| A1 | | A2 |
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+-----+ +----+
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^ ^ ^ ^ ^
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| | | | |
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+-----+ | +---------+-----+
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| | | |
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| +---+----------+
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.......!...... | |
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: A_callback : +-+--+ +-+--+
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:............: | B1 | | B2 |
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+----+ +----+
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^
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+-------+---------+
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| |
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+-+-+ ......!.......
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| C | : B_callback :
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+---+ :............:
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A_callback and B_callback are used as part of the wrapping mechanism but not
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represented in Python. C is also not represented in Python but is delivered
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there polymorphically through a smart pointer.
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This is the data structure in Python.
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ExtensionClass<A1>
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A1: +------------+
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()<--+- __bases__ |
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| __dict__ -+->{...}
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+------------+
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^
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| ExtensionInstance
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| a1: +---------------------+ vec InstanceValueHolder<A1,A_callback>
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+---------+- __class__ | +---+ +---------------------+
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| | m_wrapped_objects -+->| *-+-->| contains A_callback |
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| +---------------------+ +---+ +---------------------+
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| ExtensionInstance
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| pa1_a1: +---------------------+ vec InstancePtrHolder<auto_ptr<A1>,A1>
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+---------+- __class__ | +---+ +---+
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| | m_wrapped_objects -+->| *-+-->| *-+-+ A1
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| +---------------------+ +---+ +---+ | +---+
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| +->| |
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| ExtensionInstance +---+
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| pb1_a1: +---------------------+ vec InstancePtrHolder<auto_ptr<A1>,A1>
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+---------+- __class__ | +---+ +---+
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| | m_wrapped_objects -+->| *-+-->| *-+-+ B1
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| +---------------------+ +---+ +---+ | +---+
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| +->| |
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| ExtensionInstance +---+
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| pb2_a1: +---------------------+ vec InstancePtrHolder<auto_ptr<A1>,A1>
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+---------+- __class__ | +---+ +---+
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| | m_wrapped_objects -+->| *-+-->| *-+-+ B2
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| +---------------------+ +---+ +---+ | +---+
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| +->| |
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| +---+
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| ExtensionClass<A1>
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| A2: +------------+
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| ()<--+- __bases__ |
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| | __dict__ -+->{...}
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| +------------+
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| ^
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| | ExtensionInstance
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| a2: | +---------------------+ vec InstanceValueHolder<A2>
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| +-+- __class__ | +---+ +-------------+
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| | | m_wrapped_objects -+->| *-+-->| contains A2 |
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| | +---------------------+ +---+ +-------------+
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| |
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| | ExtensionInstance
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| pa2_a2: | +---------------------+ vec InstancePtrHolder<auto_ptr<A2>,A2>
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| +-+- __class__ | +---+ +---+
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| | | m_wrapped_objects -+->| *-+-->| *-+-+ A2
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| | +---------------------+ +---+ +---+ | +---+
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| | +->| |
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| | ExtensionInstance +---+
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| pb1_a2: | +---------------------+ vec InstancePtrHolder<auto_ptr<A2>,A2>
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| +-+- __class__ | +---+ +---+
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| | | m_wrapped_objects -+->| *-+-->| *-+-+ B1
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| | +---------------------+ +---+ +---+ | +---+
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| | +->| |
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| | +---+
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| |
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| +---------------+------------------------------+
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| | |
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+------+-------------------------+-|----------------------------+ |
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| | | | |
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| Class<ExtensionInstance> | | ExtensionClass<B1> | | ExtensionClass<B1>
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| DA1: +------------+ | | B1: +------------+ | | B2: +------------+
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(*,)<---+- __bases__ | (*,*)<---+- __bases__ | (*,*)<---+- __bases__ |
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| __dict__ -+->{...} | __dict__ -+->{...} | __dict__ -+->{...}
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+------------+ +------------+ +------------+
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^ ^ ^
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| ExtensionInstance | |
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| da1: +---------------------+ | vec InstanceValueHolder<A1,A_callback>
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+-------+- __class__ | | +---+ +---------------------+ |
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| m_wrapped_objects -+--|-->| *-+-->| contains A_callback | |
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+---------------------+ | +---+ +---------------------+ |
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+--------------------------------------+ |
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| ExtensionInstance |
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b1: | +---------------------+ vec InstanceValueHolder<B1,B_callback> |
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+-+- __class__ | +---+ +---------------------+ |
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| | m_wrapped_objects -+->| *-+-->| contains B_callback | |
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| +---------------------+ +---+ +---------------------+ |
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| |
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| ExtensionInstance |
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pb1_b1: | +---------------------+ vec InstancePtrHolder<auto_ptr<B1>,B1> |
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+-+- __class__ | +---+ +---+ |
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| | m_wrapped_objects -+->| *-+-->| *-+-+ B1 |
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| +---------------------+ +---+ +---+ | +---+ |
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| +->| | |
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| ExtensionInstance +---+ |
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pc_b1: | +---------------------+ vec InstancePtrHolder<auto_ptr<B1>,B1> |
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+-+- __class__ | +---+ +---+ |
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| | m_wrapped_objects -+->| *-+-->| *-+-+ C |
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| +---------------------+ +---+ +---+ | +---+ |
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| +->| | |
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| +---+ |
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| Class<ExtensionInstance> +---------------------------------------+
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| DB1: +------------+ | ExtensionInstance
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(*,)<---+- __bases__ | a2: | +---------------------+ vec InstanceValueHolder<A2>
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| __dict__ -+->{...} +-+- __class__ | +---+ +-------------+
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+------------+ | m_wrapped_objects -+->| *-+-->| contains A2 |
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^ +---------------------+ +---+ +-------------+
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| ExtensionInstance
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db1: | +---------------------+ vec InstanceValueHolder<B1,B_callback>
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+-+- __class__ | +---+ +----------------------+
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| m_wrapped_objects -+-->| *-+-->| contains B1_callback |
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+---------------------+ +---+ +----------------------+
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