girepository: Support GError exceptions on callbacks

Generalize "throws" attribute to SignatureBlob which can be used by all
callable blob types. Keep FunctionBlob and VFuncBlob throw attributes
around and functional for compatibility. Refactor girwriter.c to write
out throws attribute for all callable types.

Based on a patch by Simon Feltman.

https://bugzilla.gnome.org/show_bug.cgi?id=729543

gicallableinfo.c

@@ -96,6 +96,17 @@ gboolean
 g_callable_info_can_throw_gerror (GICallableInfo *info)
 {
   GIRealInfo *rinfo = (GIRealInfo*)info;
+  SignatureBlob *signature;
+
+  signature = (SignatureBlob *)&rinfo->typelib->data[signature_offset (info)];
+  if (signature->throws)
+    return TRUE;
+
+  /* Functions and VFuncs store "throws" in their own blobs.
+   * This info was additionally added to the SignatureBlob
+   * to support the other callables. For Functions and VFuncs,
+   * also check their legacy flag for compatibility.
+   */
   switch (rinfo->type) {
   case GI_INFO_TYPE_FUNCTION:
     {

girnode.c

@@ -1641,7 +1641,7 @@ _g_ir_node_build_typelib (GIrNode         *node,
 	blob->getter = function->is_getter;
 	blob->constructor = function->is_constructor;
 	blob->wraps_vfunc = function->wraps_vfunc;
-	blob->throws = function->throws;
+	blob->throws = function->throws; /* Deprecated. Also stored in SignatureBlob. */
 	blob->index = 0;
 	blob->name = _g_ir_write_string (node->name, strings, data, offset2);
 	blob->symbol = _g_ir_write_string (function->symbol, strings, data, offset2);
@@ -1667,6 +1667,7 @@ _g_ir_node_build_typelib (GIrNode         *node,
         blob2->instance_transfer_ownership = function->instance_transfer_full;
 	blob2->reserved = 0;
 	blob2->n_arguments = n;
+	blob2->throws = function->throws;
 
 	signature += 4;
 
@@ -1708,6 +1709,7 @@ _g_ir_node_build_typelib (GIrNode         *node,
 	blob2->caller_owns_return_container = function->result->shallow_transfer;
 	blob2->reserved = 0;
 	blob2->n_arguments = n;
+	blob2->throws = function->throws;
 
 	signature += 4;
 
@@ -1797,7 +1799,7 @@ _g_ir_node_build_typelib (GIrNode         *node,
 	blob->must_be_implemented = 0; /* FIXME */
 	blob->must_not_be_implemented = 0; /* FIXME */
 	blob->class_closure = 0; /* FIXME */
-        blob->throws = vfunc->throws;
+	blob->throws = vfunc->throws; /* Deprecated. Also stored in SignatureBlob. */
 	blob->reserved = 0;
 
 	if (vfunc->invoker)
@@ -1825,6 +1827,7 @@ _g_ir_node_build_typelib (GIrNode         *node,
         blob2->instance_transfer_ownership = vfunc->instance_transfer_full;
 	blob2->reserved = 0;
 	blob2->n_arguments = n;
+	blob2->throws = vfunc->throws;
 
 	signature += 4;
 

girwriter.c

@@ -454,6 +454,9 @@ write_callable_info (const gchar    *namespace,
   GITypeInfo *type;
   gint i;
 
+  if (g_callable_info_can_throw_gerror (info))
+    xml_printf (file, " throws=\"1\"");
+
   write_attributes (file, (GIBaseInfo*) info);
 
   type = g_callable_info_get_return_type (info);
@@ -558,13 +561,11 @@ write_function_info (const gchar    *namespace,
   const gchar *name;
   const gchar *symbol;
   gboolean deprecated;
-  gboolean throws;
 
   flags = g_function_info_get_flags (info);
   name = g_base_info_get_name ((GIBaseInfo *)info);
   symbol = g_function_info_get_symbol (info);
   deprecated = g_base_info_is_deprecated ((GIBaseInfo *)info);
-  throws = flags & GI_FUNCTION_THROWS;
 
   if (flags & GI_FUNCTION_IS_CONSTRUCTOR)
     tag = "constructor";
@@ -585,9 +586,6 @@ write_function_info (const gchar    *namespace,
   if (deprecated)
     xml_printf (file, " deprecated=\"1\"");
 
-  if (throws)
-    xml_printf (file, " throws=\"1\"");
-
   write_callable_info (namespace, (GICallableInfo*)info, file);
   xml_end_element (file, tag);
 }
@@ -914,9 +912,6 @@ write_vfunc_info (const gchar *namespace,
   else if (flags & GI_VFUNC_MUST_NOT_OVERRIDE)
     xml_printf (file, " override=\"never\"");
 
-  if (flags & GI_VFUNC_THROWS)
-    xml_printf (file, " throws=\"1\"");
-
   xml_printf (file, " offset=\"%d\"", offset);
 
   if (invoker)

gitypelib-internal.h

@@ -467,6 +467,8 @@ typedef struct {
  *   be skipped.
  * @instance_transfer_ownership: When calling, the function assumes ownership of
  *   the instance parameter.
+ * @throws: Denotes the signature takes an additional #GError argument beyond
+ *   the annotated arguments.
  * @reserved: Reserved for future use.
  * @n_arguments: The number of arguments that this function expects, also the
  *   length of the array of ArgBlobs.
@@ -482,7 +484,8 @@ typedef struct {
   guint16        caller_owns_return_container : 1;
   guint16        skip_return                  : 1;
   guint16        instance_transfer_ownership  : 1;
-  guint16        reserved                     :11;
+  guint16        throws                       : 1;
+  guint16        reserved                     :10;
 
   guint16        n_arguments;
 
@@ -522,7 +525,7 @@ typedef struct {
  * @constructor: The function acts as a constructor for the object it is
  *   contained in.
  * @wraps_vfunc: The function is a simple wrapper for a virtual function.
- * @throws: TODO
+ * @throws: (deprecated): This is now additionally stored in the #SignatureBlob.
  * @index: Index of the property that this function is a setter or getter of
  *   in the array of properties of the containing interface, or index
  *   of the virtual function that this function wraps.
@@ -990,7 +993,7 @@ typedef struct {
  *   virtual function.
  * @class_closure: Set if this virtual function is the class closure of a
  *   signal.
- * @throws: TODO
+ * @throws: (deprecated): This is now additionally stored in the #SignatureBlob.
  * @reserved: Reserved for future use.
  * @signal: The index of the signal in the list of signals of the object or
  *   interface to which this virtual function belongs.