Merge branch '3218-girepository-stack-allocations' into 'main'

gibaseinfo: Fix use of stack-allocated GIBaseInfos

Closes #3218

See merge request GNOME/glib!3846

girepository/giarginfo.c

@@ -354,6 +354,9 @@ gi_arg_info_get_type_info (GIArgInfo *info)
  *
  * The initialized @type must not be referenced after @info is deallocated.
  *
+ * Once you are done with @type, it must be cleared using
+ * [method@GIRepository.BaseInfo.clear].
+ *
  * Since: 2.80
  */
 void
@@ -365,7 +368,7 @@ gi_arg_info_load_type (GIArgInfo  *info,
   g_return_if_fail (info != NULL);
   g_return_if_fail (GI_IS_ARG_INFO (info));
 
-  gi_type_info_init ((GIBaseInfo *) type, (GIBaseInfo*)info, rinfo->typelib, rinfo->offset + G_STRUCT_OFFSET (ArgBlob, arg_type));
+  gi_type_info_init (type, (GIBaseInfo*)info, rinfo->typelib, rinfo->offset + G_STRUCT_OFFSET (ArgBlob, arg_type));
 }
 
 void

girepository/gibaseinfo.c

@@ -123,12 +123,12 @@ value_base_info_lcopy_value (const GValue *value,
 static void
 gi_base_info_finalize (GIBaseInfo *self)
 {
-  if (self->container && self->container->ref_count != INVALID_REFCOUNT)
+  if (self->ref_count != INVALID_REFCOUNT &&
+      self->container && self->container->ref_count != INVALID_REFCOUNT)
     gi_base_info_unref (self->container);
 
-  g_clear_object (&self->repository);
+  if (self->ref_count != INVALID_REFCOUNT)
-
+    g_clear_object (&self->repository);
-  g_type_free_instance ((GTypeInstance *) self);
 }
 
 static void
@@ -141,6 +141,9 @@ gi_base_info_class_init (GIBaseInfoClass *klass)
 static void
 gi_base_info_init (GIBaseInfo *self)
 {
+  /* Initialise a dynamically allocated #GIBaseInfo’s members.
+   *
+   * This function *must* be kept in sync with gi_info_init(). */
   g_atomic_ref_count_init (&self->ref_count);
 }
 
@@ -397,7 +400,7 @@ gi_info_new (GIInfoType     type,
  */
 void
 gi_info_init (GIRealInfo   *info,
-              GIInfoType    type,
+              GType         type,
               GIRepository *repository,
               GIBaseInfo   *container,
               GITypelib    *typelib,
@@ -405,6 +408,20 @@ gi_info_init (GIRealInfo   *info,
 {
   memset (info, 0, sizeof (GIRealInfo));
 
+  /* Evil setup of a stack allocated #GTypeInstance. This is not something it’s
+   * really designed to do.
+   *
+   * This function *must* be kept in sync with gi_base_info_init(), which is
+   * the equivalent function for dynamically allocated types. */
+  info->parent_instance.g_class = g_type_class_ref (type);
+
+  /* g_type_create_instance() calls the #GInstanceInitFunc for each of the
+   * parent types, down to (and including) @type. We don’t need to do that, as
+   * #GIBaseInfo is fundamental so doesn’t have a parent type, the instance init
+   * function for #GIBaseInfo is gi_base_info_init() (which only sets the
+   * refcount, which we already do here), and subtypes of #GIBaseInfo don’t have
+   * instance init functions (see gi_base_info_type_register_static()). */
+
   /* Invalid refcount used to flag stack-allocated infos */
   info->ref_count = INVALID_REFCOUNT;
   info->typelib = typelib;
@@ -417,6 +434,34 @@ gi_info_init (GIRealInfo   *info,
   info->repository = repository;
 }
 
+/**
+ * gi_base_info_clear:
+ * @info: (type GIRepository.BaseInfo): a #GIBaseInfo
+ *
+ * Clears memory allocated internally by a stack-allocated
+ * [type@GIRepository.BaseInfo].
+ *
+ * This does not deallocate the [type@GIRepository.BaseInfo] struct itself.
+ *
+ * This must only be called on stack-allocated [type@GIRepository.BaseInfo]s.
+ * Use [method@GIRepository.BaseInfo.unref] for heap-allocated ones.
+ *
+ * Since: 2.80
+ */
+void
+gi_base_info_clear (void *info)
+{
+  GIBaseInfo *rinfo = (GIBaseInfo *) info;
+
+  g_return_if_fail (GI_IS_BASE_INFO (rinfo));
+
+  g_assert (rinfo->ref_count == INVALID_REFCOUNT);
+
+  GI_BASE_INFO_GET_CLASS (info)->finalize (rinfo);
+
+  g_type_class_unref (rinfo->parent_instance.g_class);
+}
+
 GIBaseInfo *
 gi_info_from_entry (GIRepository *repository,
                     GITypelib    *typelib,
@@ -465,8 +510,23 @@ gi_type_info_new (GIBaseInfo *container,
                                      (type->flags.reserved == 0 && type->flags.reserved2 == 0) ? offset : type->offset);
 }
 
+/*< private >
+ * gi_type_info_init:
+ * @info: (out caller-allocates): caller-allocated #GITypeInfo to populate
+ * @container: (nullable): info which contains this one
+ * @typelib: typelib containing the info
+ * @offset: offset of the info within @typelib, in bytes
+ *
+ * Initialise a stack-allocated #GITypeInfo representing an object of type
+ * [type@GIRepository.TypeInfo] from @offset of @typelib.
+ *
+ * This is a specialised form of [func@GIRepository.info_init] for type
+ * information.
+ *
+ * Since: 2.80
+ */
 void
-gi_type_info_init (GIBaseInfo *info,
+gi_type_info_init (GITypeInfo *info,
                    GIBaseInfo *container,
                    GITypelib  *typelib,
                    uint32_t    offset)
@@ -474,7 +534,7 @@ gi_type_info_init (GIBaseInfo *info,
   GIRealInfo *rinfo = (GIRealInfo*)container;
   SimpleTypeBlob *type = (SimpleTypeBlob *)&typelib->data[offset];
 
-  gi_info_init ((GIRealInfo*)info, GI_INFO_TYPE_TYPE, rinfo->repository, container, typelib,
+  gi_info_init ((GIRealInfo*)info, GI_TYPE_TYPE_INFO, rinfo->repository, container, typelib,
                 (type->flags.reserved == 0 && type->flags.reserved2 == 0) ? offset : type->offset);
 }
 
@@ -544,6 +604,9 @@ gi_base_info_ref (void *info)
  * Decreases the reference count of @info. When its reference count
  * drops to 0, the info is freed.
  *
+ * This must not be called on stack-allocated [type@GIRepository.BaseInfo]s —
+ * use [method@GIRepository.BaseInfo.clear] for that.
+ *
  * Since: 2.80
  */
 void
@@ -556,7 +619,10 @@ gi_base_info_unref (void *info)
   g_assert (rinfo->ref_count > 0 && rinfo->ref_count != INVALID_REFCOUNT);
 
   if (g_atomic_ref_count_dec (&rinfo->ref_count))
-    GI_BASE_INFO_GET_CLASS (info)->finalize (info);
+    {
+      GI_BASE_INFO_GET_CLASS (info)->finalize (info);
+      g_type_free_instance ((GTypeInstance *) info);
+    }
 }
 
 /**

girepository/gibaseinfo.h

@@ -94,6 +94,9 @@ GIBaseInfo *           gi_base_info_ref              (void         *info);
 GI_AVAILABLE_IN_ALL
 void                   gi_base_info_unref            (void         *info);
 
+GI_AVAILABLE_IN_ALL
+void                   gi_base_info_clear            (void         *info);
+
 GI_AVAILABLE_IN_ALL
 GIInfoType             gi_base_info_get_info_type    (GIBaseInfo   *info);
 

girepository/gicallableinfo.c

@@ -201,6 +201,9 @@ gi_callable_info_get_return_type (GICallableInfo *info)
  *
  * The initialized @type must not be referenced after @info is deallocated.
  *
+ * Once you are done with @type, it must be cleared using
+ * [method@GIRepository.BaseInfo.clear].
+ *
  * Since: 2.80
  */
 void
@@ -215,7 +218,7 @@ gi_callable_info_load_return_type (GICallableInfo *info,
 
   offset = signature_offset (info);
 
-  gi_type_info_init ((GIBaseInfo *) type, (GIBaseInfo*)info, rinfo->typelib, offset);
+  gi_type_info_init (type, (GIBaseInfo*)info, rinfo->typelib, offset);
 }
 
 /**
@@ -389,6 +392,9 @@ gi_callable_info_get_arg (GICallableInfo *info,
  *
  * The initialized @arg must not be referenced after @info is deallocated.
  *
+ * Once you are done with @arg, it must be cleared using
+ * [method@GIRepository.BaseInfo.clear].
+ *
  * Since: 2.80
  */
 void
@@ -407,7 +413,7 @@ gi_callable_info_load_arg (GICallableInfo *info,
   offset = signature_offset (info);
   header = (Header *)rinfo->typelib->data;
 
-  gi_info_init ((GIRealInfo*)arg, GI_INFO_TYPE_ARG, rinfo->repository, (GIBaseInfo*)info, rinfo->typelib,
+  gi_info_init ((GIRealInfo*)arg, GI_TYPE_ARG_INFO, rinfo->repository, (GIBaseInfo*)info, rinfo->typelib,
                 offset + header->signature_blob_size + n * header->arg_blob_size);
 }
 

girepository/girepository-private.h

@@ -48,6 +48,7 @@ struct _GIBaseInfo
   GTypeInstance parent_instance;
   gatomicrefcount ref_count;
 
+  /* these are both reffed if the GIBaseInfo is heap-allocated, but not reffed if it’s stack-allocated */
   GIRepository *repository;
   GIBaseInfo *container;
 
@@ -222,7 +223,7 @@ void gi_unresolved_info_class_init (gpointer g_class,
                                     gpointer class_data);
 
 void         gi_info_init       (GIRealInfo   *info,
-                                 GIInfoType    type,
+                                 GType         type,
                                  GIRepository *repository,
                                  GIBaseInfo   *container,
                                  GITypelib    *typelib,
@@ -242,7 +243,7 @@ GITypeInfo * gi_type_info_new   (GIBaseInfo *container,
                                  GITypelib  *typelib,
                                  uint32_t    offset);
 
-void         gi_type_info_init  (GIBaseInfo *info,
+void         gi_type_info_init  (GITypeInfo *info,
                                  GIBaseInfo *container,
                                  GITypelib  *typelib,
                                  uint32_t    offset);

girepository/girffi.c

@@ -220,6 +220,9 @@ gi_callable_info_get_ffi_arg_types (GICallableInfo *callable_info,
             default:
               g_assert_not_reached ();
           }
+
+        gi_base_info_clear (&arg_type);
+        gi_base_info_clear (&arg_info);
       }
 
     arg_types[n_invoke_args] = NULL;
@@ -266,6 +269,9 @@ gi_callable_info_get_ffi_return_type (GICallableInfo *callable_info)
  * by a language binding could contain a [type@GIRepository.FunctionInvoker]
  * structure inside the binding’s function mapping.
  *
+ * @invoker must be freed using [method@GIRepository.FunctionInvoker.clear]
+ * when it’s finished with.
+ *
  * Returns: `TRUE` on success, `FALSE` otherwise with @error set.
  * Since: 2.80
  */
@@ -336,7 +342,7 @@ gi_function_invoker_new_for_address (void               *addr,
 }
 
 /**
- * gi_function_invoker_destroy:
+ * gi_function_invoker_clear:
  * @invoker: (transfer none): A #GIFunctionInvoker
  *
  * Release all resources allocated for the internals of @invoker.
@@ -347,7 +353,7 @@ gi_function_invoker_new_for_address (void               *addr,
  * Since: 2.80
  */
 void
-gi_function_invoker_destroy (GIFunctionInvoker *invoker)
+gi_function_invoker_clear (GIFunctionInvoker *invoker)
 {
   g_free (invoker->cif.arg_types);
 }

girepository/girffi.h

@@ -108,7 +108,7 @@ gboolean      gi_function_invoker_new_for_address  (void                 *addr,
                                                     GError              **error);
 
 GI_AVAILABLE_IN_ALL
-void          gi_function_invoker_destroy          (GIFunctionInvoker    *invoker);
+void          gi_function_invoker_clear            (GIFunctionInvoker    *invoker);
 
 
 GI_AVAILABLE_IN_ALL

girepository/tests/function-info.c

@@ -0,0 +1,88 @@
+/*
+ * Copyright 2024 Philip Chimento
+ * Copyright 2024 GNOME Foundation, Inc.
+ *
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General
+ * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ *
+ * Author: Philip Withnall <pwithnall@gnome.org>
+ */
+
+#include "glib.h"
+#include "girepository.h"
+#include "girffi.h"
+
+static GIRepository *
+load_typelib_from_builddir (const char *name,
+                            const char *version)
+{
+  GIRepository *repository;
+  char *gobject_typelib_dir = NULL;
+  GITypelib *typelib = NULL;
+  GError *local_error = NULL;
+
+  gobject_typelib_dir = g_test_build_filename (G_TEST_BUILT, "..", "..", "introspection", NULL);
+  g_test_message ("Using GI_TYPELIB_DIR = %s", gobject_typelib_dir);
+  gi_repository_prepend_search_path (gobject_typelib_dir);
+  g_free (gobject_typelib_dir);
+
+  repository = gi_repository_new ();
+  g_assert_nonnull (repository);
+
+  typelib = gi_repository_require (repository, name, version, 0, &local_error);
+  g_assert_no_error (local_error);
+  g_assert_nonnull (typelib);
+
+  return g_steal_pointer (&repository);
+}
+
+static void
+test_function_info_invoker (void)
+{
+  GIRepository *repository;
+  GIFunctionInfo *function_info = NULL;
+  GIFunctionInvoker invoker;
+  GError *local_error = NULL;
+
+  g_test_summary ("Test preparing a function invoker");
+
+  repository = load_typelib_from_builddir ("GLib", "2.0");
+
+  function_info = (GIFunctionInfo *) gi_repository_find_by_name (repository, "GLib", "get_locale_variants");
+  g_assert_nonnull (function_info);
+
+  gi_function_info_prep_invoker (function_info, &invoker, &local_error);
+  g_assert_no_error (local_error);
+
+  gi_function_invoker_clear (&invoker);
+  g_clear_pointer (&function_info, gi_base_info_unref);
+
+  g_clear_object (&repository);
+}
+
+int
+main (int   argc,
+      char *argv[])
+{
+  /* Isolate from the system typelibs and GIRs. */
+  g_setenv ("GI_TYPELIB_PATH", "/dev/null", TRUE);
+  g_setenv ("GI_GIR_PATH", "/dev/null", TRUE);
+
+  g_test_init (&argc, &argv, G_TEST_OPTION_ISOLATE_DIRS, NULL);
+
+  g_test_add_func ("/function-info/invoker", test_function_info_invoker);
+
+  return g_test_run ();
+}

girepository/tests/meson.build

@@ -6,6 +6,9 @@ if enable_gir
     'cmph-bdz': {
       'dependencies': [cmph_dep],
     },
+    'function-info' : {
+      'depends': [glib_gir],
+    },
     'gthash' : {
       'dependencies': [girepo_gthash_dep],
     },