定义并注册Callback class
以下Callback是在非Python所创建的线程中回调Python中的方法，所以在执行任何Python相关的调用前，最好先调用PyGILState_Ensure，另外使用boost::python::call_method来调用Python对象中的方法。
非Python创建的线程
PyGILState_Ensure
call_method
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|
class Callback
{
public:
Callback()
: m_self(nullptr)
{
}
explicit Callback(PyObject* self)
: m_self(self)
{
}
Callback(const Callback& other) noexcept
: m_self(other.m_self)
{
incref();
}
Callback(Callback&& other) noexcept
{
m_self = other.m_self;
other.m_self = nullptr;
}
Callback& operator=(const Callback& other) noexcept
{
m_self = other.m_self;
incref();
return *this;
}
Callback& operator=(Callback&& other) noexcept
{
m_self = other.m_self;
other.m_self = nullptr;
return *this;
}
virtual ~Callback()
{
decref();
}
void incref()
{
if (!m_self) {
return;
}
PyGILState_STATE state = PyGILState_Ensure();
Py_INCREF(m_self);
PyGILState_Release(state);
}
void decref()
{
if (!m_self || !Py_REFCNT(m_self)) {
return;
}
PyGILState_STATE state = PyGILState_Ensure();
Py_DECREF(m_self);
PyGILState_Release(state);
}
void dispatch(const std::string message)
{
if (!m_self) {
return;
}
PyGILState_STATE state = PyGILState_Ensure();
try {
call_method<void>(m_self, "event", std::string(message), boost::python::object());
}
catch (const boost::python::error_already_set&) {
boost::python::handle_exception();
}
catch (const std::exception&) {
boost::python::handle_exception();
}
PyGILState_Release(state);
}
void dispatch(const std::string message, boost::python::dict& data)
{
if (!m_self) {
return;
}
PyGILState_STATE state = PyGILState_Ensure();
try {
call_method<void>(m_self, "event", std::string(message), data.copy());
}
catch (const boost::python::error_already_set&) {
boost::python::handle_exception();
}
catch (const std::exception&) {
boost::python::handle_exception();
}
PyGILState_Release(state);
}
protected:
PyObject* m_self;
};
|
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| BOOST_PYTHON_MODULE(FooModule)
{
class_<Callback, boost::noncopyable>("Callback", init<PyObject*>());
}
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补充注册回调方法
下面这个例子会在注册回调函数时启动一个C/C++运行时线程，休眠一秒后执行回调。
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| void register_callback(Callback& callback)
{
std::thread([](Callback callback) {
std::this_thread::sleep_for(std::chrono::milliseconds(1000));
callback.dispatch("message_one");
PyGILState_STATE state = PyGILState_Ensure();
{
boost::python::dict data;
data["key"] = "ten";
data["value"] = 10;
callback.dispatch("message_two", data);
}
PyGILState_Release(state);
std::this_thread::sleep_for(std::chrono::milliseconds(1000));
}, callback).detach();
}
|
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| BOOST_PYTHON_MODULE(FooModule)
{
class_<Callback, boost::noncopyable>("Callback", init<PyObject*>());
def("register_callback", register_callback);
}
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Python测试代码
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| class MyCallback(FooModule.Callback):
def __init__(self):
FooModule.Callback.__init__(self, self)
def event(self, message, data=None):
print(message)
print(data)
FooModule.register_callback(MyCallback())
|
