Parse and expose ownership transfer for instance parameters

Knowing the ownership transfer for instance parameters is
necessary for correct memory management of functions which
"eat" their instance argument, such as g_dbus_method_invocation_return_*.
Parse this information from the gir file and store in the
typelib, and then provide new API on GICallableInfo to
retrieve this.

https://bugzilla.gnome.org/show_bug.cgi?id=729662

gicallableinfo.c

@@ -275,6 +275,32 @@ g_callable_info_get_caller_owns (GICallableInfo *info)
     return GI_TRANSFER_NOTHING;
 }
 
+/**
+ * g_callable_info_get_instance_ownership_transfer:
+ * @info: a #GICallableInfo
+ *
+ * Obtains the ownership transfer for the instance argument.
+ * #GITransfer contains a list of possible transfer values.
+ *
+ * Returns: the transfer
+ */
+GITransfer
+g_callable_info_get_instance_ownership_transfer (GICallableInfo *info)
+{
+  GIRealInfo *rinfo = (GIRealInfo*) info;
+  SignatureBlob *blob;
+
+  g_return_val_if_fail (info != NULL, -1);
+  g_return_val_if_fail (GI_IS_CALLABLE_INFO (info), -1);
+
+  blob = (SignatureBlob *)&rinfo->typelib->data[signature_offset (info)];
+
+  if (blob->instance_transfer_ownership)
+    return GI_TRANSFER_EVERYTHING;
+  else
+    return GI_TRANSFER_NOTHING;
+}
+
 /**
  * g_callable_info_get_n_args:
  * @info: a #GICallableInfo

gicallableinfo.h

@@ -73,6 +73,8 @@ gboolean               g_callable_info_invoke          (GICallableInfo   *info,
                                                         gboolean          is_method,
                                                         gboolean          throws,
                                                         GError          **error);
+GITransfer             g_callable_info_get_instance_ownership_transfer (GICallableInfo *info);
+
 G_END_DECLS
 
 

girepository.symbols

@@ -26,6 +26,7 @@ g_info_new
 g_callable_info_can_throw_gerror
 g_callable_info_get_arg
 g_callable_info_get_caller_owns
+g_callable_info_get_instance_ownership_transfer
 g_callable_info_get_n_args
 g_callable_info_get_return_attribute
 g_callable_info_get_return_type

girnode.c

@@ -1664,6 +1664,7 @@ _g_ir_node_build_typelib (GIrNode         *node,
 	blob2->caller_owns_return_value = function->result->transfer;
 	blob2->caller_owns_return_container = function->result->shallow_transfer;
 	blob2->skip_return = function->result->skip;
+        blob2->instance_transfer_ownership = function->instance_transfer_full;
 	blob2->reserved = 0;
 	blob2->n_arguments = n;
 
@@ -1762,6 +1763,7 @@ _g_ir_node_build_typelib (GIrNode         *node,
 	blob2->may_return_null = signal->result->nullable;
 	blob2->caller_owns_return_value = signal->result->transfer;
 	blob2->caller_owns_return_container = signal->result->shallow_transfer;
+        blob2->instance_transfer_ownership = signal->instance_transfer_full;
 	blob2->reserved = 0;
 	blob2->n_arguments = n;
 
@@ -1820,6 +1822,7 @@ _g_ir_node_build_typelib (GIrNode         *node,
 	blob2->may_return_null = vfunc->result->nullable;
 	blob2->caller_owns_return_value = vfunc->result->transfer;
 	blob2->caller_owns_return_container = vfunc->result->shallow_transfer;
+        blob2->instance_transfer_ownership = vfunc->instance_transfer_full;
 	blob2->reserved = 0;
 	blob2->n_arguments = n;
 

girnode.h

@@ -100,6 +100,7 @@ struct _GIrNodeFunction
   gboolean is_constructor;
   gboolean wraps_vfunc;
   gboolean throws;
+  gboolean instance_transfer_full;
 
   gchar *symbol;
 
@@ -188,6 +189,7 @@ struct _GIrNodeSignal
   gboolean detailed;
   gboolean action;
   gboolean no_hooks;
+  gboolean instance_transfer_full;
 
   gboolean has_class_closure;
   gboolean true_stops_emit;
@@ -208,6 +210,7 @@ struct _GIrNodeVFunc
   gboolean must_not_be_implemented;
   gboolean is_class_closure;
   gboolean throws;
+  gboolean instance_transfer_full;
 
   char *invoker;
 

girparser.c

@@ -1046,6 +1046,71 @@ parse_param_transfer (GIrNodeParam *param, const gchar *transfer, const gchar *n
   return TRUE;
 }
 
+static gboolean
+start_instance_parameter (GMarkupParseContext *context,
+                          const gchar         *element_name,
+                          const gchar        **attribute_names,
+                          const gchar        **attribute_values,
+                          ParseContext        *ctx,
+                          GError             **error)
+{
+  const gchar *transfer;
+  gboolean transfer_full;
+
+  if (!(strcmp (element_name, "instance-parameter") == 0 &&
+	ctx->state == STATE_FUNCTION_PARAMETERS))
+    return FALSE;
+
+  transfer = find_attribute ("transfer-ownership", attribute_names, attribute_values);
+
+  state_switch (ctx, STATE_PASSTHROUGH);
+
+  if (strcmp (transfer, "full") == 0)
+    transfer_full = TRUE;
+  else if (strcmp (transfer, "none") == 0)
+    transfer_full = FALSE;
+  else
+    {
+      g_set_error (error, G_MARKUP_ERROR,
+		   G_MARKUP_ERROR_INVALID_CONTENT,
+		   "invalid value for 'transfer-ownership' for instance parameter: %s", transfer);
+      return FALSE;
+    }
+
+  switch (CURRENT_NODE (ctx)->type)
+    {
+    case G_IR_NODE_FUNCTION:
+    case G_IR_NODE_CALLBACK:
+      {
+	GIrNodeFunction *func;
+
+	func = (GIrNodeFunction *)CURRENT_NODE (ctx);
+        func->instance_transfer_full = transfer_full;
+      }
+      break;
+    case G_IR_NODE_SIGNAL:
+      {
+	GIrNodeSignal *signal;
+
+	signal = (GIrNodeSignal *)CURRENT_NODE (ctx);
+        signal->instance_transfer_full = transfer_full;
+      }
+      break;
+    case G_IR_NODE_VFUNC:
+      {
+	GIrNodeVFunc *vfunc;
+
+	vfunc = (GIrNodeVFunc *)CURRENT_NODE (ctx);
+        vfunc->instance_transfer_full = transfer_full;
+      }
+      break;
+    default:
+      g_assert_not_reached ();
+    }
+
+  return TRUE;
+}
+
 static gboolean
 start_parameter (GMarkupParseContext *context,
 		 const gchar         *element_name,
@@ -2848,11 +2913,10 @@ start_element_handler (GMarkupParseContext *context,
 				 attribute_names, attribute_values,
 				 ctx, error))
 	goto out;
-      else if (strcmp (element_name, "instance-parameter") == 0)
-        {
-          state_switch (ctx, STATE_PASSTHROUGH);
-          goto out;
-        }
+      else if (start_instance_parameter (context, element_name,
+				attribute_names, attribute_values,
+				ctx, error))
+	goto out;
       else if (strcmp (element_name, "c:include") == 0)
 	{
 	  state_switch (ctx, STATE_C_INCLUDE);

gitypelib-internal.h

@@ -465,6 +465,8 @@ typedef struct {
  *   freeing the container, but not its contents.
  * @skip_return: Indicates that the return value is only useful in C and should
  *   be skipped.
+ * @instance_transfer_ownership: When calling, the function assumes ownership of
+ *   the instance parameter.
  * @reserved: Reserved for future use.
  * @n_arguments: The number of arguments that this function expects, also the
  *   length of the array of ArgBlobs.
@@ -479,7 +481,8 @@ typedef struct {
   guint16        caller_owns_return_value     : 1;
   guint16        caller_owns_return_container : 1;
   guint16        skip_return                  : 1;
-  guint16        reserved                     :12;
+  guint16        instance_transfer_ownership  : 1;
+  guint16        reserved                     :11;
 
   guint16        n_arguments;