bpy_rna_callback.c

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/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * Contributor(s): Campbell Barton
 *
 * ***** END GPL LICENSE BLOCK *****
 */

#include <Python.h>

#include "RNA_types.h"

#include "bpy_rna.h"
#include "bpy_rna_callback.h"
#include "bpy_util.h"

#include "BLI_utildefines.h"

#include "DNA_screen_types.h"

#include "RNA_access.h"

#include "BKE_context.h"
#include "ED_space_api.h"

/* use this to stop other capsules from being mis-used */
#define RNA_CAPSULE_ID "RNA_HANDLE"
#define RNA_CAPSULE_ID_INVALID "RNA_HANDLE_REMOVED"

static void cb_region_draw(const bContext *C, ARegion *UNUSED(ar), void *customdata)
{
    PyObject *cb_func, *cb_args, *result;
    PyGILState_STATE gilstate;

    bpy_context_set((bContext *)C, &gilstate);

    cb_func = PyTuple_GET_ITEM((PyObject *)customdata, 0);
    cb_args = PyTuple_GET_ITEM((PyObject *)customdata, 1);
    result = PyObject_CallObject(cb_func, cb_args);

    if (result) {
        Py_DECREF(result);
    }
    else {
        PyErr_Print();
        PyErr_Clear();
    }

    bpy_context_clear((bContext *)C, &gilstate);
}

PyObject *pyrna_callback_add(BPy_StructRNA *self, PyObject *args)
{
    void *handle;

    PyObject *cb_func, *cb_args;
    char *cb_event_str = NULL;
    int cb_event;

    if (!PyArg_ParseTuple(args, "OO!|s:bpy_struct.callback_add", &cb_func, &PyTuple_Type, &cb_args, &cb_event_str))
        return NULL;
    
    if (!PyCallable_Check(cb_func)) {
        PyErr_SetString(PyExc_TypeError, "callback_add(): first argument isn't callable");
        return NULL;
    }

    if (RNA_struct_is_a(self->ptr.type, &RNA_Region)) {
        if (cb_event_str) {
            static EnumPropertyItem region_draw_mode_items[] = {
                {REGION_DRAW_POST_PIXEL, "POST_PIXEL", 0, "Post Pixel", ""},
                {REGION_DRAW_POST_VIEW, "POST_VIEW", 0, "Post View", ""},
                {REGION_DRAW_PRE_VIEW, "PRE_VIEW", 0, "Pre View", ""},
                {0, NULL, 0, NULL, NULL}};
    
            if (pyrna_enum_value_from_id(region_draw_mode_items, cb_event_str, &cb_event, "bpy_struct.callback_add()") < 0) {
                return NULL;
            }
        }
        else {
            cb_event = REGION_DRAW_POST_PIXEL;
        }

        handle = ED_region_draw_cb_activate(((ARegion *)self->ptr.data)->type, cb_region_draw, (void *)args, cb_event);
        Py_INCREF(args);
    }
    else {
        PyErr_SetString(PyExc_TypeError, "callback_add(): type does not suppport callbacks");
        return NULL;
    }

    return PyCapsule_New((void *)handle, RNA_CAPSULE_ID, NULL);
}

PyObject *pyrna_callback_remove(BPy_StructRNA *self, PyObject *args)
{
    PyObject *py_handle;
    void *handle;
    void *customdata;

    if (!PyArg_ParseTuple(args, "O!:callback_remove", &PyCapsule_Type, &py_handle))
        return NULL;

    handle = PyCapsule_GetPointer(py_handle, RNA_CAPSULE_ID);

    if (handle == NULL) {
        PyErr_SetString(PyExc_ValueError, "callback_remove(handle): NULL handle given, invalid or already removed");
        return NULL;
    }

    if (RNA_struct_is_a(self->ptr.type, &RNA_Region)) {
        customdata = ED_region_draw_cb_customdata(handle);
        Py_DECREF((PyObject *)customdata);

        ED_region_draw_cb_exit(((ARegion *)self->ptr.data)->type, handle);
    }

    /* dont allow reuse */
    PyCapsule_SetName(py_handle, RNA_CAPSULE_ID_INVALID);

    Py_RETURN_NONE;
}