C++ PyThread_get_key_value函数代码示例

/* The public functions */
PyThreadState *
PyGILState_GetThisThreadState(void)
{
    if (autoInterpreterState == NULL)
        return NULL;
    return (PyThreadState *)PyThread_get_key_value(autoTLSkey);
}

PyGILState_STATE
PyGILState_Ensure(void)
{
    int current;
    PyThreadState *tcur;
    /* Note that we do not auto-init Python here - apart from
       potential races with 2 threads auto-initializing, pep-311
       spells out other issues.  Embedders are expected to have
       called Py_Initialize() and usually PyEval_InitThreads().
    */
    assert(autoInterpreterState); /* Py_Initialize() hasn't been called! */
    tcur = (PyThreadState *)PyThread_get_key_value(autoTLSkey);
    if (tcur == NULL) {
        /* Create a new thread state for this thread */
        tcur = PyThreadState_New(autoInterpreterState);
        if (tcur == NULL)
            Py_FatalError("Couldn't create thread-state for new thread");
        /* This is our thread state!  We'll need to delete it in the
           matching call to PyGILState_Release(). */
        tcur->gilstate_counter = 0;
        current = 0; /* new thread state is never current */
    }
    else
        current = PyThreadState_IsCurrent(tcur);
    if (current == 0)
        PyEval_RestoreThread(tcur);
    /* Update our counter in the thread-state - no need for locks:
       - tcur will remain valid as we hold the GIL.
       - the counter is safe as we are the only thread "allowed"
         to modify this value
    */
    ++tcur->gilstate_counter;
    return current ? PyGILState_LOCKED : PyGILState_UNLOCKED;
}

/* When a thread state is created for a thread by some mechanism other than
   PyGILState_Ensure, it's important that the GILState machinery knows about
   it so it doesn't try to create another thread state for the thread (this is
   a better fix for SF bug #1010677 than the first one attempted).
*/
static void
_PyGILState_NoteThreadState(PyThreadState* tstate)
{
    /* If autoTLSkey isn't initialized, this must be the very first
       threadstate created in Py_Initialize().  Don't do anything for now
       (we'll be back here when _PyGILState_Init is called). */
    if (!autoInterpreterState)
        return;

    /* Stick the thread state for this thread in thread local storage.

       The only situation where you can legitimately have more than one
       thread state for an OS level thread is when there are multiple
       interpreters.

       You shouldn't really be using the PyGILState_ APIs anyway (see issues
       #10915 and #15751).

       The first thread state created for that given OS level thread will
       "win", which seems reasonable behaviour.
    */
    if (PyThread_get_key_value(autoTLSkey) == NULL) {
        if (PyThread_set_key_value(autoTLSkey, (void *)tstate) < 0)
            Py_FatalError("Couldn't create autoTLSkey mapping");
    }

    /* PyGILState_Release must not try to delete this thread state. */
    tstate->gilstate_counter = 1;
}

static inline GMainLoop *
pyg_get_current_main_loop (void)
{
    if (pyg_current_main_loop_key == -1)
	return NULL;
    return PyThread_get_key_value(pyg_current_main_loop_key);
}

/* Internal initialization/finalization functions called by
   Py_Initialize/Py_Finalize
*/
void
_PyGILState_Init(PyInterpreterState *i, PyThreadState *t)
{
    assert(i && t); /* must init with valid states */
    autoTLSkey = PyThread_create_key();
    autoInterpreterState = i;
    assert(PyThread_get_key_value(autoTLSkey) == NULL);
    assert(t->gilstate_counter == 0);

    _PyGILState_NoteThreadState(t);
}

void
PyThreadState_Delete(PyThreadState *tstate)
{
    if (tstate == _PyThreadState_Current)
        Py_FatalError("PyThreadState_Delete: tstate is still current");
    tstate_delete_common(tstate);
#ifdef WITH_THREAD
    if (autoInterpreterState && PyThread_get_key_value(autoTLSkey) == tstate)
        PyThread_delete_key_value(autoTLSkey);
#endif /* WITH_THREAD */
}

void
PyThreadState_DeleteCurrent()
{
    PyThreadState *tstate = _PyThreadState_Current;
    if (tstate == NULL)
        Py_FatalError(
            "PyThreadState_DeleteCurrent: no current tstate");
    _PyThreadState_Current = NULL;
    tstate_delete_common(tstate);
    if (autoInterpreterState && PyThread_get_key_value(autoTLSkey) == tstate)
        PyThread_delete_key_value(autoTLSkey);
    PyEval_ReleaseLock();
}

/* Internal initialization/finalization functions called by
   Py_Initialize/Py_Finalize
*/
void
_PyGILState_Init(PyInterpreterState *i, PyThreadState *t)
{
    assert(i && t); /* must init with valid states */
    autoTLSkey = PyThread_create_key();
    if (autoTLSkey == -1)
        Py_FatalError("Could not allocate TLS entry");
    autoInterpreterState = i;
    assert(PyThread_get_key_value(autoTLSkey) == NULL);
    assert(t->gilstate_counter == 0);

    _PyGILState_NoteThreadState(t);
}

void
PyThreadState_DeleteCurrent()
{
    PyThreadState *tstate = (PyThreadState*)_Py_atomic_load_relaxed(
        &_PyThreadState_Current);
    if (tstate == NULL)
        Py_FatalError(
            "PyThreadState_DeleteCurrent: no current tstate");
    _Py_atomic_store_relaxed(&_PyThreadState_Current, NULL);
    if (autoInterpreterState && PyThread_get_key_value(autoTLSkey) == tstate)
        PyThread_delete_key_value(autoTLSkey);
    tstate_delete_common(tstate);
    PyEval_ReleaseLock();
}

static inline void
pyg_restore_current_main_loop (GMainLoop *main_loop)
{
    GMainLoop *prev;

    g_return_if_fail (pyg_current_main_loop_key != -1);

    prev = PyThread_get_key_value(pyg_current_main_loop_key);
    if (prev != NULL)
	g_main_loop_unref(prev);
    PyThread_delete_key_value(pyg_current_main_loop_key);
    if (main_loop != NULL)
	PyThread_set_key_value(pyg_current_main_loop_key, main_loop);
}

static inline GMainLoop *
pyg_save_current_main_loop (GMainLoop *main_loop)
{
    GMainLoop *retval;

    g_return_val_if_fail(main_loop != NULL, NULL);

    if (pyg_current_main_loop_key == -1)
	pyg_current_main_loop_key = PyThread_create_key();

    retval = PyThread_get_key_value(pyg_current_main_loop_key);
    PyThread_delete_key_value(pyg_current_main_loop_key);
    PyThread_set_key_value(pyg_current_main_loop_key, 
			   g_main_loop_ref(main_loop));

    return retval;
}

void
PyGILState_Release(PyGILState_STATE oldstate)
{
    PyThreadState *tcur = (PyThreadState *)PyThread_get_key_value(
                                                            autoTLSkey);
    if (tcur == NULL)
        Py_FatalError("auto-releasing thread-state, "
                      "but no thread-state for this thread");
    /* We must hold the GIL and have our thread state current */
    /* XXX - remove the check - the assert should be fine,
       but while this is very new (April 2003), the extra check
       by release-only users can't hurt.
    */
    if (! PyThreadState_IsCurrent(tcur))
        Py_FatalError("This thread state must be current when releasing");
    assert(PyThreadState_IsCurrent(tcur));
    --tcur->gilstate_counter;
    assert(tcur->gilstate_counter >= 0); /* illegal counter value */

    /* If we're going to destroy this thread-state, we must
     * clear it while the GIL is held, as destructors may run.
     */
    if (tcur->gilstate_counter == 0) {
        /* can't have been locked when we created it */
        assert(oldstate == PyGILState_UNLOCKED);
        PyThreadState_Clear(tcur);
        /* Delete the thread-state.  Note this releases the GIL too!
         * It's vital that the GIL be held here, to avoid shutdown
         * races; see bugs 225673 and 1061968 (that nasty bug has a
         * habit of coming back).
         */
        PyThreadState_DeleteCurrent();
    }
    /* Release the lock if necessary */
    else if (oldstate == PyGILState_UNLOCKED)
        PyEval_SaveThread();
}