C++ PyEval_AcquireLock函数代码示例

void python_taskqueue::run( GLFWwindow *Context, rendertask_sequence &Tasks, threading::condition_variable &Condition, std::atomic<bool> &Exit ) {

    glfwMakeContextCurrent( Context );
    // create a state object for this thread
    PyEval_AcquireLock();
    auto *threadstate { PyThreadState_New( m_mainthread->interp ) };
    PyEval_ReleaseLock();

    render_task *task { nullptr };

    while( false == Exit.load() ) {
        // regardless of the reason we woke up prime the spurious wakeup flag for the next time
        Condition.spurious( true );
        // keep working as long as there's any scheduled tasks
        do {
            task = nullptr;
            // acquire a lock on the task queue and potentially grab a task from it
            {
                std::lock_guard<std::mutex> lock( Tasks.mutex );
                if( false == Tasks.data.empty() ) {
                    // fifo
                    task = Tasks.data.front();
                    Tasks.data.pop_front();
                }
            }
            if( task != nullptr ) {
                // swap in my thread state
                PyEval_RestoreThread( threadstate );
                {
                    // execute python code
                    task->run();
                    error();
                }
                // clear the thread state
                PyEval_SaveThread();
            }
            // TBD, TODO: add some idle time between tasks in case we're on a single thread cpu?
        } while( task != nullptr );
        // if there's nothing left to do wait until there is
        // but check every now and then on your own to minimize potential deadlock situations
        Condition.wait_for( std::chrono::seconds( 5 ) );
    }
    // clean up thread state data
    PyEval_AcquireLock();
    PyThreadState_Swap( nullptr );
    PyThreadState_Clear( threadstate );
    PyThreadState_Delete( threadstate );
    PyEval_ReleaseLock();
}

static void
TargetCleanup(void *self, void *data)
{
    /* Decrement _PLUGIN_COUNT, protected by _PLUGIN_INIT_MUTEX
     * call Py_Finalize when _PLUGIN_COUNT drops to zero
     */
    if (pthread_mutex_lock(&_PLUGIN_INIT_MUTEX))
    {
        perror("Can't lock _PLUGIN_INIT_MUTEX");
        abort();
    }
    if (--_PLUGIN_COUNT > 0) 
    {
        pthread_mutex_unlock(&_PLUGIN_INIT_MUTEX);
        return;
    }

    TARGET_THREAD_BEGIN_BLOCK;
    Py_DecRef(_TARGET_MODULE);
    TARGET_THREAD_END_BLOCK;
  
    PyEval_AcquireLock(); 
    PyThreadState_Swap(pluginMainPyThreadState); 
    if (_TARGET_INIT)  // if Python is initialized and _PLUGIN_COUNT == 0, call Py_Finalize
    {
        debug("Calling Py_Finalize()");
        Py_Finalize();
        _TARGET_INIT=0; // false
    }
    pthread_mutex_unlock(&_PLUGIN_INIT_MUTEX);

}

bool KviPythonInterpreter::execute(
		const QString &szCode,
		QStringList &lArgs, //args
		QString &szRetVal,
		QString &szError,
		QStringList &) //lWarnings
{
	if(!m_pThreadState)
	{
		szError = __tr2qs_ctx("Internal error: python interpreter not initialized","python");
		return false;
	}

	int retVal;
	g_lError.clear();

	// grab the global interpreter lock
	PyEval_AcquireLock();
	// swap in my thread state
	PyThreadState_Swap(m_pThreadState);

	QString szVarCode = "aArgs = [";

	bool bFirst = true;
	foreach(QString szArg,lArgs)
	{
		if(!bFirst)
			szVarCode += ",";
		else
			bFirst = false;

		szVarCode += QString::fromLatin1("\"%1\"").arg(szArg);
	}

	szVarCode += "]";

	PyRun_SimpleString(szVarCode.toUtf8().data());

	//clean "cr" from the python code (ticket #1028)
	QString szCleanCode = szCode;
	szCleanCode.replace(QRegExp("\r\n?"), "\n");
	// execute some python code
	retVal = PyRun_SimpleString(szCleanCode.toUtf8().data());

	szRetVal.setNum(retVal);

	if (PyErr_Occurred() || retVal)
	{
		szError = g_lError;
	}

	// clear the thread state
	PyThreadState_Swap(NULL);
	// release our hold on the global interpreter
	PyEval_ReleaseLock();

	if(retVal)
		return false;
	return true;
}

void XBPython::Finalize()
{
  if (m_bInitialized)
  {
    CLog::Log(LOGINFO, "Python, unloading python shared library because no scripts are running anymore");

    PyEval_AcquireLock();
    PyThreadState_Swap((PyThreadState*)m_mainThreadState);

    Py_Finalize();
    PyEval_ReleaseLock();

#if !(defined(__APPLE__) || defined(_WIN32))
    UnloadExtensionLibs();
#endif

    // first free all dlls loaded by python, after that python24.dll (this is done by UnloadPythonDlls
#if !(defined(__APPLE__) || defined(_WIN32))
    DllLoaderContainer::UnloadPythonDlls();
#endif
#if defined(_LINUX) && !defined(__APPLE__)
    // we can't release it on windows, as this is done in UnloadPythonDlls() for win32 (see above).
    // The implementation for linux needs looking at - UnloadPythonDlls() currently only searches for "python24.dll"
    // The implementation for osx can never unload the python dylib.
    DllLoaderContainer::ReleaseModule(m_pDll);
#endif
    m_hModule         = NULL;
    m_mainThreadState = NULL;
    m_bInitialized    = false;
  }
}

void XBPyThread::stop()
{
  CSingleLock lock(m_pExecuter->m_critSection);
  if(m_stopping)
    return;

  m_stopping = true;

  if (m_threadState)
  {
    PyEval_AcquireLock();
    PyThreadState* old = PyThreadState_Swap((PyThreadState*)m_threadState);

    PyObject *m;
    m = PyImport_AddModule((char*)"xbmc");
    if(!m || PyObject_SetAttrString(m, (char*)"abortRequested", PyBool_FromLong(1)))
      CLog::Log(LOGERROR, "XBPyThread::stop - failed to set abortRequested");

    for(PyThreadState* state = ((PyThreadState*)m_threadState)->interp->tstate_head; state; state = state->next)
    {
      Py_XDECREF(state->async_exc);
      state->async_exc = PyExc_SystemExit;
      Py_XINCREF(state->async_exc);
    }

    PyThreadState_Swap(old);
    PyEval_ReleaseLock();
  }
}

bool KviPythonInterpreter::init()
{
// get the global lock
	PyEval_AcquireLock();
	// get a reference to the PyInterpreterState
	PyInterpreterState * mainInterpreterState = mainThreadState->interp;
	// create a thread state object for this thread
	m_pThreadState = PyThreadState_New(mainInterpreterState);
	// swap in the current thread state
	PyThreadState_Swap(m_pThreadState);
	// and hook in the kvirc error handling routines
	QString szPreCode = QString( \
		"import kvirc\n" \
		"import sys\n" \
		"class kvirc_stderr_grabber:\n" \
		"\tdef write(self,s):\n" \
		"\t\tkvirc.error(s)\n" \
		"sys.stderr=kvirc_stderr_grabber()\n"
	);
	// evaluate that
	PyRun_SimpleString(szPreCode.toUtf8().data());
	// swap out our thread state for now
	PyThreadState_Swap(NULL);

	// free the lock
	PyEval_ReleaseLock();
	return true;
}

void init()
{

	if (etiss::cfg().get<bool>("pyinitialize",true))
	{
		Py_Initialize();
		if (etiss::cfg().get<bool>("pyinittheads",true))
		{
			if (PyEval_ThreadsInitialized()==0)
			{
				PyEval_InitThreads(); // init gil
				PyEval_ReleaseLock(); // release gil
				etiss::log(etiss::VERBOSE,"PyEval_InitThreads() called.");
			}
		}
		etiss::log(etiss::VERBOSE,"Py_Initialize() called.");
	}

	run([]()
	{
		PyEval_AcquireLock(); // lock gil
		if (etiss::verbosity() >= etiss::INFO)
			PyRun_SimpleString("print('ETISS: INFO: ETISS has been build with python support.')\n");
		//Py_InitModule3("etiss", ETISSMethods,"ETISS python bindings");
		PyEval_ReleaseLock(); // release gil
	});

}

static int rw_write_th(SDL_RWops* context, const void* ptr, int size, int num)
{
	RWHelper* helper = (RWHelper*)context->hidden.unknown.data1;
	PyObject* result;
        PyThreadState* oldstate;

	if(!helper->write)
		return -1;

        PyEval_AcquireLock();
        oldstate = PyThreadState_Swap(helper->thread);

	result = PyObject_CallFunction(helper->write, "s#", ptr, size * num);
	if(!result) {
                PyThreadState_Swap(oldstate);
                PyEval_ReleaseLock();

		return -1;
        }
                
	Py_DECREF(result);

        PyThreadState_Swap(oldstate);
        PyEval_ReleaseLock();

	return num;
}

PythonModule* PythonModule_Init( PythonEnv* Environment, char* ModuleName )
{
  PyObject* pName;
  
  PythonModule* Self = (PythonModule*) malloc( sizeof(PythonModule) );
  Self->Module=NULL;
  Self->List = NULL;
  Self->ListLength = 0;
  Self->ModuleName = (char*) malloc( sizeof(char) * strlen(ModuleName)+1 );
  strcpy( Self->ModuleName, ModuleName );

  Self->Environment = Environment;
  
  PyEval_AcquireLock(); 
  Self->CurrentThreadState = PyThreadState_New( Self->Environment->MainThreadState->interp );
  PyThreadState_Swap( Self->CurrentThreadState );

  pName = PyString_FromString(Self->ModuleName);

  Self->Module = PyImport_Import(pName);
  
  if( Self->Module == NULL )
  {
    PyErr_Print();
    PythonModule_LeaveThread( Self );
    PythonModule_Destroy( Self );
    return NULL;
  }

  Py_INCREF(Self->Module);
  Py_DECREF(pName);

  PythonModule_LeaveThread( Self ); 
  return Self;
}

static int rw_close_th(SDL_RWops* context)
{
	RWHelper* helper = (RWHelper*)context->hidden.unknown.data1;
	PyObject* result;
	int retval = 0;
        PyThreadState* oldstate;

        PyEval_AcquireLock();
        oldstate = PyThreadState_Swap(helper->thread);

	if(helper->close)
	{
		result = PyObject_CallFunction(helper->close, NULL);
		if(result)
			retval = -1;
		Py_XDECREF(result);
	}

        PyThreadState_Swap(oldstate);
        PyThreadState_Clear(helper->thread);
        PyThreadState_Delete(helper->thread);

	Py_XDECREF(helper->seek);
	Py_XDECREF(helper->tell);
	Py_XDECREF(helper->write);
	Py_XDECREF(helper->read);
	Py_XDECREF(helper->close);
	PyMem_Del(helper);

        PyEval_ReleaseLock();

	SDL_FreeRW(context);
	return retval;
}

/*
 * Create a new instance of the plugin i.e. allocate our private storage
 */
static bRC newPlugin(bpContext *ctx)
{
   struct plugin_ctx *p_ctx;

   p_ctx = (struct plugin_ctx *)malloc(sizeof(struct plugin_ctx));
   if (!p_ctx) {
      return bRC_Error;
   }
   memset(p_ctx, 0, sizeof(struct plugin_ctx));
   ctx->pContext = (void *)p_ctx;        /* set our context pointer */

   /*
    * For each plugin instance we instantiate a new Python interpreter.
    */
   PyEval_AcquireLock();
   p_ctx->interpreter = Py_NewInterpreter();
   PyEval_ReleaseThread(p_ctx->interpreter);

   /*
    * Always register some events the python plugin itself can register
    * any other events it is interested in.
    */
   bfuncs->registerBareosEvents(ctx,
                                1,
                                bsdEventNewPluginOptions);

   return bRC_OK;
}

int PythonEnv_Destroy( PythonEnv* Self )
{
  PyEval_AcquireLock();
  PyThreadState_Swap(Self->MainThreadState); 
  Py_Finalize();
  free( Self );
  return 0;
}

void ModuleLoader::finalize()
{
	PyEval_AcquireLock();

	PyThreadState_Swap( g_pymaintstate );

	Py_Finalize();
}

/**
 * Execute the current script
 * We are now in the thread.
 */
void PyApi::ExecuteInThread() const
{
  assert(Py_IsInitialized() );
  
  // get the lock so we can change things.
  PyEval_AcquireLock();

  // make sure that the main thread is the active one.
  const auto  mainInterpreterState = _mainThreadState->interp;
  PyThreadState_Swap(_mainThreadState);

  // create a new thread.
  const auto  myThreadState =  PyThreadState_New(mainInterpreterState);

  // make sure that the new thread has control
  // https://docs.python.org/3/c-api/init.html
  PyThreadState_Swap(myThreadState);

  //  execute it...
  {
    const auto main_module = PyImport_AddModule("__main__");
    const auto main_dict = PyModule_GetDict(main_module);
    Py_XINCREF(main_module);
 
    const auto local_dic = PyDict_New();
    Py_XINCREF(local_dic);

    // we can now run our script
    const auto s = _script.c_str();
    const auto pyRes = PyRun_String(s, Py_file_input, main_dict, local_dic);

    CheckForPythonErrors();

    PyDict_Clear(local_dic);
    Py_XDECREF(local_dic);

    // pending calls must be cleared out
    Py_XDECREF(main_module);
  }

  // swap back to this thread.
  PyThreadState_Swap(myThreadState);

  // clear anything left behind.
  PyThreadState_Clear(myThreadState);

  PyThreadState_Swap(nullptr);

  // delete my thread.
  PyThreadState_Delete(myThreadState);

  //  give control back to main thread
  PyThreadState_Swap(_mainThreadState);

  // release the lock one last time.
  PyEval_ReleaseLock();
}

 void End()
 {
     PyEval_AcquireLock();
     PyThreadState_Swap( NULL );
     PyThreadState_Clear( mainThreadState );
     PyThreadState_Delete( mainThreadState );
     //PyEval_Restore( mainThreadState );
     Py_Finalize();
     started = ScriptEngine::HasBegun();
 }