[gobject-introspection] gitypeinfo: Add pointer-stuffing functions for GITypeTag storage type

[Emmanuele Bassi <ebassi src gnome org>]

commit 649905fc906a3768c3d77a13e2d86f1753d51ec2
Author: Philip Chimento <philip chimento gmail com>
Date:   Wed Feb 16 10:37:39 2022 -0800

    gitypeinfo: Add pointer-stuffing functions for GITypeTag storage type
    
    This adds gi_type_tag_argument_from_hash_pointer() and
    gi_type_tag_hash_pointer_from_argument(). They do the same thing as
    the corresponding g_type_info_... functions, which are used to pack and
    unpack the correct field of a GIArgument into/from a data pointer in
    GHashTable or GList, regardless of machine architecture or endianness.
    
    These functions take a GITypeTag obtained from
    g_type_info_get_storage_type(), instead of a GITypeInfo pointer. (The
    storage type is the only piece of data that is actually used from the
    GITypeInfo structure.)
    
    It's intended for bindings using an argument cache, such as GJS and
    PyGObject, so that they don't have to store a whole 64-bit GITypeInfo
    pointer in their cache in many common cases, and can just store the 5-bit
    type tag instead.
    
    The original g_type_info_... functions are reimplemented in
    terms of the new g_type_tag... functions.

 girepository/gitypeinfo.c | 95 +++++++++++++++++++++++++++++++++++++----------
 girepository/gitypeinfo.h |  9 +++++
 2 files changed, 84 insertions(+), 20 deletions(-)
---
diff --git a/girepository/gitypeinfo.c b/girepository/gitypeinfo.c
index bdcc1c65..6aa10e05 100644
--- a/girepository/gitypeinfo.c
+++ b/girepository/gitypeinfo.c
@@ -372,8 +372,8 @@ g_type_info_get_storage_type (GITypeInfo *info)
 }
 
 /**
- * g_type_info_argument_from_hash_pointer:
- * @info: a #GITypeInfo
+ * gi_type_tag_argument_from_hash_pointer:
+ * @storage_type: a #GITypeTag obtained from g_type_info_get_storage_type()
  * @hash_pointer: A pointer, such as a #GHashTable data pointer
  * @arg: A #GIArgument to fill in
  *
@@ -387,18 +387,16 @@ g_type_info_get_storage_type (GITypeInfo *info)
  * stuffed pointers, regardless of the machine's architecture or endianness.
  *
  * This function fills in the appropriate field of @arg with the value extracted
- * from @hash_pointer, depending on the storage type of @info.
+ * from @hash_pointer, depending on @storage_type.
  *
- * Since: 1.66
+ * Since: 1.72
  */
 void
-g_type_info_argument_from_hash_pointer (GITypeInfo *info,
-                                        gpointer hash_pointer,
+gi_type_tag_argument_from_hash_pointer (GITypeTag   storage_type,
+                                        gpointer    hash_pointer,
                                         GIArgument *arg)
 {
-  GITypeTag type_tag = g_type_info_get_storage_type (info);
-
-  switch (type_tag)
+  switch (storage_type)
     {
       case GI_TYPE_TAG_BOOLEAN:
         arg->v_boolean = !!GPOINTER_TO_INT (hash_pointer);
@@ -440,15 +438,45 @@ g_type_info_argument_from_hash_pointer (GITypeInfo *info,
       case GI_TYPE_TAG_FLOAT:
       case GI_TYPE_TAG_DOUBLE:
       default:
-        g_critical ("Unsupported type for pointer-stuffing: %s",
-                    g_type_tag_to_string (type_tag));
+        g_critical ("Unsupported storage type for pointer-stuffing: %s",
+                    g_type_tag_to_string (storage_type));
         arg->v_pointer = hash_pointer;
     }
 }
 
 /**
- * g_type_info_hash_pointer_from_argument:
+ * g_type_info_argument_from_hash_pointer:
  * @info: a #GITypeInfo
+ * @hash_pointer: A pointer, such as a #GHashTable data pointer
+ * @arg: A #GIArgument to fill in
+ *
+ * GLib data structures, such as #GList, #GSList, and #GHashTable, all store
+ * data pointers.
+ * In the case where the list or hash table is storing single types rather than
+ * structs, these data pointers may have values stuffed into them via macros
+ * such as %GPOINTER_TO_INT.
+ *
+ * Use this function to ensure that all values are correctly extracted from
+ * stuffed pointers, regardless of the machine's architecture or endianness.
+ *
+ * This function fills in the appropriate field of @arg with the value extracted
+ * from @hash_pointer, depending on the storage type of @info.
+ *
+ * Since: 1.66
+ */
+void
+g_type_info_argument_from_hash_pointer (GITypeInfo *info,
+                                        gpointer    hash_pointer,
+                                        GIArgument *arg)
+{
+    GITypeTag storage_type = g_type_info_get_storage_type (info);
+    return gi_type_tag_argument_from_hash_pointer (storage_type, hash_pointer,
+                                                   arg);
+}
+
+/**
+ * gi_type_tag_hash_pointer_from_argument:
+ * @storage_type: a #GITypeTag obtained from g_type_info_get_storage_type()
  * @arg: A #GIArgument with the value to stuff into a pointer
  *
  * GLib data structures, such as #GList, #GSList, and #GHashTable, all store
@@ -461,19 +489,17 @@ g_type_info_argument_from_hash_pointer (GITypeInfo *info,
  * pointers, regardless of the machine's architecture or endianness.
  *
  * This function returns a pointer stuffed with the appropriate field of @arg,
- * depending on the storage type of @info.
+ * depending on @storage_type.
  *
  * Returns: A stuffed pointer, that can be stored in a #GHashTable, for example
  *
- * Since: 1.66
+ * Since: 1.72
  */
 gpointer
-g_type_info_hash_pointer_from_argument (GITypeInfo *info,
+gi_type_tag_hash_pointer_from_argument (GITypeTag   storage_type,
                                         GIArgument *arg)
 {
-  GITypeTag type_tag = g_type_info_get_storage_type (info);
-
-  switch (type_tag)
+  switch (storage_type)
     {
       case GI_TYPE_TAG_BOOLEAN:
         return GINT_TO_POINTER (arg->v_boolean);
@@ -506,8 +532,37 @@ g_type_info_hash_pointer_from_argument (GITypeInfo *info,
       case GI_TYPE_TAG_FLOAT:
       case GI_TYPE_TAG_DOUBLE:
       default:
-        g_critical ("Unsupported type for pointer-stuffing: %s",
-                    g_type_tag_to_string (type_tag));
+        g_critical ("Unsupported storage type for pointer-stuffing: %s",
+                    g_type_tag_to_string (storage_type));
         return arg->v_pointer;
     }
 }
+
+/**
+ * g_type_info_hash_pointer_from_argument:
+ * @info: a #GITypeInfo
+ * @arg: A #GIArgument with the value to stuff into a pointer
+ *
+ * GLib data structures, such as #GList, #GSList, and #GHashTable, all store
+ * data pointers.
+ * In the case where the list or hash table is storing single types rather than
+ * structs, these data pointers may have values stuffed into them via macros
+ * such as %GPOINTER_TO_INT.
+ *
+ * Use this function to ensure that all values are correctly stuffed into
+ * pointers, regardless of the machine's architecture or endianness.
+ *
+ * This function returns a pointer stuffed with the appropriate field of @arg,
+ * depending on the storage type of @info.
+ *
+ * Returns: A stuffed pointer, that can be stored in a #GHashTable, for example
+ *
+ * Since: 1.66
+ */
+gpointer
+g_type_info_hash_pointer_from_argument (GITypeInfo *info,
+                                        GIArgument *arg)
+{
+  GITypeTag storage_type = g_type_info_get_storage_type (info);
+  return gi_type_tag_hash_pointer_from_argument (storage_type, arg);
+}
diff --git a/girepository/gitypeinfo.h b/girepository/gitypeinfo.h
index 39912ae7..283658ef 100644
--- a/girepository/gitypeinfo.h
+++ b/girepository/gitypeinfo.h
@@ -146,6 +146,15 @@ GI_AVAILABLE_IN_1_66
 gpointer               g_type_info_hash_pointer_from_argument (GITypeInfo *info,
                                                                GIArgument *arg);
 
+GI_AVAILABLE_IN_1_72
+void                   gi_type_tag_argument_from_hash_pointer (GITypeTag   storage_type,
+                                                               gpointer    hash_pointer,
+                                                               GIArgument *arg);
+
+GI_AVAILABLE_IN_1_72
+gpointer               gi_type_tag_hash_pointer_from_argument (GITypeTag   storage_type,
+                                                               GIArgument *arg);
+
 G_END_DECLS