gi/pygi-object.c

   1 /* -*- Mode: C; c-basic-offset: 4 -*-
   2  * vim: tabstop=4 shiftwidth=4 expandtab
   3  *
   4  * Copyright (C) 2011 John (J5) Palmieri <johnp@redhat.com>
   5  * Copyright (C) 2014 Simon Feltman <sfeltman@gnome.org>
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * This library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include <Python.h>
  22 #include <glib.h>
  23 #include <pyglib-python-compat.h>
  24
  25 #include "pygi-object.h"
  26 #include "pygobject-object.h"
  27 #include "pygparamspec.h"
  28
  29 /*
  30  * GObject from Python
  31  */
  32
  33 typedef gboolean (*PyGIObjectMarshalFromPyFunc) (PyObject *py_arg,
  34                                                  GIArgument *arg,
  35                                                  GITransfer transfer);
  36
  37 /* _pygi_marshal_from_py_gobject:
  38  * py_arg: (in):
  39  * arg: (out):
  40  */
  41 static gboolean
  42 _pygi_marshal_from_py_gobject (PyObject *py_arg, /*in*/
  43                                GIArgument *arg,  /*out*/
  44                                GITransfer transfer) {
  45     GObject *gobj;
  46
  47     if (py_arg == Py_None) {
  48         arg->v_pointer = NULL;
  49         return TRUE;
  50     }
  51
  52     if (!pygobject_check (py_arg, &PyGObject_Type)) {
  53         PyObject *repr = PyObject_Repr (py_arg);
  54         PyErr_Format(PyExc_TypeError, "expected GObject but got %s",
  55                      PYGLIB_PyUnicode_AsString (repr));
  56         Py_DECREF (repr);
  57         return FALSE;
  58     }
  59
  60     gobj = pygobject_get (py_arg);
  61     if (gobj == NULL) {
  62         PyErr_Format(PyExc_RuntimeError, "object at %p of type %s is not initialized",
  63                      py_arg, Py_TYPE(py_arg)->tp_name);
  64         return FALSE;
  65     }
  66
  67     if (transfer == GI_TRANSFER_EVERYTHING) {
  68         /* For transfer everything, add a new ref that the callee will take ownership of.
  69          * Pythons existing ref to the GObject will be managed with the PyGObject wrapper.
  70          */
  71         g_object_ref (gobj);
  72     }
  73
  74     arg->v_pointer = gobj;
  75     return TRUE;
  76 }
  77
  78 /* pygi_arg_gobject_out_arg_from_py:
  79  * py_arg: (in):
  80  * arg: (out):
  81  *
  82  * A specialization for marshaling Python GObjects used for out/return values
  83  * from a Python implemented vfuncs, signals, or an assignment to a GObject property.
  84  */
  85 gboolean
  86 pygi_arg_gobject_out_arg_from_py (PyObject *py_arg, /*in*/
  87                                   GIArgument *arg,  /*out*/
  88                                   GITransfer transfer) {
  89     GObject *gobj;
  90     if (!_pygi_marshal_from_py_gobject (py_arg, arg, transfer)) {
  91         return FALSE;
  92     }
  93
  94     /* HACK: At this point the basic marshaling of the GObject was successful
  95      * but we add some special case hacks for vfunc returns due to buggy APIs:
  96      * https://bugzilla.gnome.org/show_bug.cgi?id=693393
  97      */
  98     gobj = arg->v_pointer;
  99     if (py_arg->ob_refcnt == 1 && gobj->ref_count == 1) {
 100         /* If both object ref counts are only 1 at this point (the reference held
 101          * in a return tuple), we assume the GObject will be free'd before reaching
 102          * its target and become invalid. So instead of getting invalid object errors
 103          * we add a new GObject ref.
 104          */
 105         g_object_ref (gobj);
 106
 107         if (((PyGObject *)py_arg)->private_flags.flags & PYGOBJECT_GOBJECT_WAS_FLOATING) {
 108             /*
 109              * We want to re-float instances that were floating and the Python
 110              * wrapper assumed ownership. With the additional caveat that there
 111              * are not any strong references beyond the return tuple.
 112              */
 113             g_object_force_floating (gobj);
 114
 115         } else {
 116             PyObject *repr = PyObject_Repr (py_arg);
 117             gchar *msg = g_strdup_printf ("Expecting to marshal a borrowed reference for %s, "
 118                                           "but nothing in Python is holding a reference to this object. "
 119                                           "See: https://bugzilla.gnome.org/show_bug.cgi?id=687522",
 120                                           PYGLIB_PyUnicode_AsString(repr));
 121             Py_DECREF (repr);
 122             if (PyErr_WarnEx (PyExc_RuntimeWarning, msg, 2)) {
 123                 g_free (msg);
 124                 return FALSE;
 125             }
 126             g_free (msg);
 127         }
 128     }
 129
 130     return TRUE;
 131 }
 132
 133 static gboolean
 134 _pygi_marshal_from_py_interface_object (PyGIInvokeState             *state,
 135                                         PyGICallableCache           *callable_cache,
 136                                         PyGIArgCache                *arg_cache,
 137                                         PyObject                    *py_arg,
 138                                         GIArgument                  *arg,
 139                                         gpointer                    *cleanup_data,
 140                                         PyGIObjectMarshalFromPyFunc  func)
 141 {
 142     PyGIInterfaceCache *iface_cache = (PyGIInterfaceCache *)arg_cache;
 143
 144     if (py_arg == Py_None) {
 145         arg->v_pointer = NULL;
 146         return TRUE;
 147     }
 148
 149     if (PyObject_IsInstance (py_arg, iface_cache->py_type) ||
 150             (pygobject_check (py_arg, &PyGObject_Type) &&
 151              g_type_is_a (G_OBJECT_TYPE (pygobject_get (py_arg)), iface_cache->g_type))) {
 152
 153         gboolean res;
 154         res = func (py_arg, arg, arg_cache->transfer);
 155         *cleanup_data = arg->v_pointer;
 156         return res;
 157
 158     } else {
 159         PyObject *module = PyObject_GetAttrString(py_arg, "__module__");
 160
 161         PyErr_Format (PyExc_TypeError, "argument %s: Expected %s, but got %s%s%s",
 162                       arg_cache->arg_name ? arg_cache->arg_name : "self",
 163                       ( (PyGIInterfaceCache *)arg_cache)->type_name,
 164                       module ? PYGLIB_PyUnicode_AsString(module) : "",
 165                       module ? "." : "",
 166                       py_arg->ob_type->tp_name);
 167         if (module)
 168             Py_DECREF (module);
 169         return FALSE;
 170     }
 171 }
 172
 173 static gboolean
 174 _pygi_marshal_from_py_called_from_c_interface_object (PyGIInvokeState   *state,
 175                                                       PyGICallableCache *callable_cache,
 176                                                       PyGIArgCache      *arg_cache,
 177                                                       PyObject          *py_arg,
 178                                                       GIArgument        *arg,
 179                                                       gpointer          *cleanup_data)
 180 {
 181     return _pygi_marshal_from_py_interface_object (state,
 182                                                    callable_cache,
 183                                                    arg_cache,
 184                                                    py_arg,
 185                                                    arg,
 186                                                    cleanup_data,
 187                                                    pygi_arg_gobject_out_arg_from_py);
 188 }
 189
 190 static gboolean
 191 _pygi_marshal_from_py_called_from_py_interface_object (PyGIInvokeState   *state,
 192                                                        PyGICallableCache *callable_cache,
 193                                                        PyGIArgCache      *arg_cache,
 194                                                        PyObject          *py_arg,
 195                                                        GIArgument        *arg,
 196                                                        gpointer          *cleanup_data)
 197 {
 198     return _pygi_marshal_from_py_interface_object (state,
 199                                                    callable_cache,
 200                                                    arg_cache,
 201                                                    py_arg,
 202                                                    arg,
 203                                                    cleanup_data,
 204                                                    _pygi_marshal_from_py_gobject);
 205 }
 206
 207 static void
 208 _pygi_marshal_cleanup_from_py_interface_object (PyGIInvokeState *state,
 209                                                 PyGIArgCache    *arg_cache,
 210                                                 PyObject        *py_arg,
 211                                                 gpointer         data,
 212                                                 gboolean         was_processed)
 213 {
 214     /* If we processed the parameter but fail before invoking the method,
 215        we need to remove the ref we added */
 216     if (was_processed && state->failed && data != NULL &&
 217             arg_cache->transfer == GI_TRANSFER_EVERYTHING)
 218         g_object_unref (G_OBJECT(data));
 219 }
 220
 221
 222 /*
 223  * GObject to Python
 224  */
 225
 226 PyObject *
 227 pygi_arg_gobject_to_py (GIArgument *arg, GITransfer transfer) {
 228     PyObject *pyobj;
 229
 230     if (arg->v_pointer == NULL) {
 231         pyobj = Py_None;
 232         Py_INCREF (pyobj);
 233
 234     } else if (G_IS_PARAM_SPEC(arg->v_pointer)) {
 235         pyobj = pyg_param_spec_new (arg->v_pointer);
 236         if (transfer == GI_TRANSFER_EVERYTHING)
 237             g_param_spec_unref (arg->v_pointer);
 238
 239     } else {
 240          pyobj = pygobject_new_full (arg->v_pointer,
 241                                      /*steal=*/ transfer == GI_TRANSFER_EVERYTHING,
 242                                      /*type=*/  NULL);
 243     }
 244
 245     return pyobj;
 246 }
 247
 248 PyObject *
 249 pygi_arg_gobject_to_py_called_from_c (GIArgument *arg,
 250                                       GITransfer  transfer)
 251 {
 252     PyObject *object;
 253
 254     /* HACK:
 255      * The following hack is to work around GTK+ sending signals which
 256      * contain floating widgets in them. This assumes control of how
 257      * references are added by the PyGObject wrapper and avoids the sink
 258      * behavior by explicitly passing GI_TRANSFER_EVERYTHING as the transfer
 259      * mode and then re-forcing the object as floating afterwards.
 260      *
 261      * See: https://bugzilla.gnome.org/show_bug.cgi?id=693400
 262      */
 263     if (arg->v_pointer != NULL &&
 264             transfer == GI_TRANSFER_NOTHING &&
 265             !G_IS_PARAM_SPEC (arg->v_pointer) &&
 266             g_object_is_floating (arg->v_pointer)) {
 267
 268         g_object_ref (arg->v_pointer);
 269         object = pygi_arg_gobject_to_py (arg, GI_TRANSFER_EVERYTHING);
 270         g_object_force_floating (arg->v_pointer);
 271     } else {
 272         object = pygi_arg_gobject_to_py (arg, transfer);
 273     }
 274
 275     return object;
 276 }
 277
 278 static PyObject *
 279 _pygi_marshal_to_py_called_from_c_interface_object_cache_adapter (PyGIInvokeState   *state,
 280                                                                   PyGICallableCache *callable_cache,
 281                                                                   PyGIArgCache      *arg_cache,
 282                                                                   GIArgument        *arg,
 283                                                                   gpointer          *cleanup_data)
 284 {
 285     return pygi_arg_gobject_to_py_called_from_c (arg, arg_cache->transfer);
 286 }
 287
 288 static PyObject *
 289 _pygi_marshal_to_py_called_from_py_interface_object_cache_adapter (PyGIInvokeState   *state,
 290                                                                    PyGICallableCache *callable_cache,
 291                                                                    PyGIArgCache      *arg_cache,
 292                                                                    GIArgument        *arg,
 293                                                                    gpointer          *cleanup_data)
 294 {
 295     return pygi_arg_gobject_to_py (arg, arg_cache->transfer);
 296 }
 297
 298 static void
 299 _pygi_marshal_cleanup_to_py_interface_object (PyGIInvokeState *state,
 300                                               PyGIArgCache    *arg_cache,
 301                                               gpointer         cleanup_data,
 302                                               gpointer         data,
 303                                               gboolean         was_processed)
 304 {
 305     /* If we error out and the object is not marshalled into a PyGObject
 306        we must take care of removing the ref */
 307     if (!was_processed && arg_cache->transfer == GI_TRANSFER_EVERYTHING)
 308         g_object_unref (G_OBJECT(data));
 309 }
 310
 311 static gboolean
 312 pygi_arg_gobject_setup_from_info (PyGIArgCache      *arg_cache,
 313                                   GITypeInfo        *type_info,
 314                                   GIArgInfo         *arg_info,
 315                                   GITransfer         transfer,
 316                                   PyGIDirection      direction,
 317                                   PyGICallableCache *callable_cache)
 318 {
 319     /* NOTE: usage of pygi_arg_interface_new_from_info already calls
 320      * pygi_arg_interface_setup so no need to do it here.
 321      */
 322
 323     if (direction & PYGI_DIRECTION_FROM_PYTHON) {
 324         if (callable_cache->calling_context == PYGI_CALLING_CONTEXT_IS_FROM_C) {
 325             arg_cache->from_py_marshaller = _pygi_marshal_from_py_called_from_c_interface_object;
 326         } else {
 327             arg_cache->from_py_marshaller = _pygi_marshal_from_py_called_from_py_interface_object;
 328         }
 329
 330         arg_cache->from_py_cleanup = _pygi_marshal_cleanup_from_py_interface_object;
 331     }
 332
 333     if (direction & PYGI_DIRECTION_TO_PYTHON) {
 334         if (callable_cache->calling_context == PYGI_CALLING_CONTEXT_IS_FROM_C) {
 335             arg_cache->to_py_marshaller = _pygi_marshal_to_py_called_from_c_interface_object_cache_adapter;
 336         } else {
 337             arg_cache->to_py_marshaller = _pygi_marshal_to_py_called_from_py_interface_object_cache_adapter;
 338         }
 339
 340         arg_cache->to_py_cleanup = _pygi_marshal_cleanup_to_py_interface_object;
 341     }
 342
 343     return TRUE;
 344 }
 345
 346 PyGIArgCache *
 347 pygi_arg_gobject_new_from_info (GITypeInfo        *type_info,
 348                                 GIArgInfo         *arg_info,
 349                                 GITransfer         transfer,
 350                                 PyGIDirection      direction,
 351                                 GIInterfaceInfo   *iface_info,
 352                                 PyGICallableCache *callable_cache)
 353 {
 354     gboolean res = FALSE;
 355     PyGIArgCache *cache = NULL;
 356
 357     cache = pygi_arg_interface_new_from_info (type_info,
 358                                               arg_info,
 359                                               transfer,
 360                                               direction,
 361                                               iface_info);
 362     if (cache == NULL)
 363         return NULL;
 364
 365     res = pygi_arg_gobject_setup_from_info (cache,
 366                                             type_info,
 367                                             arg_info,
 368                                             transfer,
 369                                             direction,
 370                                             callable_cache);
 371     if (res) {
 372         return cache;
 373     } else {
 374         pygi_arg_cache_free (cache);
 375         return NULL;
 376     }
 377 }