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girepository: Add GITypeInfo utility functions for storing values in pointers

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This functionality is used in both PyGObject and GJS, and if not done
correctly can lead to architecture-specific bugs. It seems best to add
API in gobject-introspection for the correct way to do it.

See also: GNOME/gjs#309
This commit is contained in:
Philip Chimento
2020-04-11 14:22:18 -07:00
parent 8fcdeefb3a
commit 7daee7b90a
2 changed files with 182 additions and 0 deletions
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170
gitypeinfo.c
View File

@@ -347,3 +347,173 @@ g_type_info_get_array_type (GITypeInfo *info)
return -1; return -1;
} }
/**
* g_type_info_get_storage_type:
* @info: a #GITypeInfo
*
* Obtain the type tag corresponding to the underlying storage type in C for
* the type.
* See #GITypeTag for a list of type tags.
*
* Returns: the type tag
*
* Since: 1.66
*/
GITypeTag
g_type_info_get_storage_type (GITypeInfo *info)
{
GITypeTag type_tag = g_type_info_get_tag (info);
if (type_tag == GI_TYPE_TAG_INTERFACE)
{
GIBaseInfo *interface = g_type_info_get_interface (info);
GIInfoType info_type = g_base_info_get_type (interface);
if (info_type == GI_INFO_TYPE_ENUM || info_type == GI_INFO_TYPE_FLAGS)
type_tag = g_enum_info_get_storage_type (interface);
g_base_info_unref (interface);
}
return type_tag;
}
/**
* 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 type_tag = g_type_info_get_storage_type (info);
switch (type_tag)
{
case GI_TYPE_TAG_BOOLEAN:
arg->v_boolean = !!GPOINTER_TO_INT (hash_pointer);
break;
case GI_TYPE_TAG_INT8:
arg->v_int8 = (gint8)GPOINTER_TO_INT (hash_pointer);
break;
case GI_TYPE_TAG_UINT8:
arg->v_uint8 = (guint8)GPOINTER_TO_UINT (hash_pointer);
break;
case GI_TYPE_TAG_INT16:
arg->v_int16 = (gint16)GPOINTER_TO_INT (hash_pointer);
break;
case GI_TYPE_TAG_UINT16:
arg->v_uint16 = (guint16)GPOINTER_TO_UINT (hash_pointer);
break;
case GI_TYPE_TAG_INT32:
arg->v_int32 = (gint32)GPOINTER_TO_INT (hash_pointer);
break;
case GI_TYPE_TAG_UINT32:
case GI_TYPE_TAG_UNICHAR:
arg->v_uint32 = (guint32)GPOINTER_TO_UINT (hash_pointer);
break;
case GI_TYPE_TAG_GTYPE:
arg->v_size = GPOINTER_TO_SIZE (hash_pointer);
break;
case GI_TYPE_TAG_UTF8:
case GI_TYPE_TAG_FILENAME:
case GI_TYPE_TAG_INTERFACE:
case GI_TYPE_TAG_ARRAY:
case GI_TYPE_TAG_GLIST:
case GI_TYPE_TAG_GSLIST:
case GI_TYPE_TAG_GHASH:
case GI_TYPE_TAG_ERROR:
arg->v_pointer = hash_pointer;
break;
case GI_TYPE_TAG_INT64:
case GI_TYPE_TAG_UINT64:
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));
arg->v_pointer = hash_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 type_tag = g_type_info_get_storage_type (info);
switch (type_tag)
{
case GI_TYPE_TAG_BOOLEAN:
return GINT_TO_POINTER (arg->v_boolean);
case GI_TYPE_TAG_INT8:
return GINT_TO_POINTER (arg->v_int8);
case GI_TYPE_TAG_UINT8:
return GUINT_TO_POINTER (arg->v_uint8);
case GI_TYPE_TAG_INT16:
return GINT_TO_POINTER (arg->v_int16);
case GI_TYPE_TAG_UINT16:
return GUINT_TO_POINTER (arg->v_uint16);
case GI_TYPE_TAG_INT32:
return GINT_TO_POINTER (arg->v_int32);
case GI_TYPE_TAG_UINT32:
case GI_TYPE_TAG_UNICHAR:
return GUINT_TO_POINTER (arg->v_uint32);
case GI_TYPE_TAG_GTYPE:
return GSIZE_TO_POINTER (arg->v_size);
case GI_TYPE_TAG_UTF8:
case GI_TYPE_TAG_FILENAME:
case GI_TYPE_TAG_INTERFACE:
case GI_TYPE_TAG_ARRAY:
case GI_TYPE_TAG_GLIST:
case GI_TYPE_TAG_GSLIST:
case GI_TYPE_TAG_GHASH:
case GI_TYPE_TAG_ERROR:
return arg->v_pointer;
case GI_TYPE_TAG_INT64:
case GI_TYPE_TAG_UINT64:
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));
return arg->v_pointer;
}
}

12
gitypeinfo.h
View File

@@ -80,6 +80,18 @@ gboolean g_type_info_is_zero_terminated (GITypeInfo *info);
GI_AVAILABLE_IN_ALL GI_AVAILABLE_IN_ALL
GIArrayType g_type_info_get_array_type (GITypeInfo *info); GIArrayType g_type_info_get_array_type (GITypeInfo *info);
GI_AVAILABLE_IN_1_66
GITypeTag g_type_info_get_storage_type (GITypeInfo *info);
GI_AVAILABLE_IN_1_66
void g_type_info_argument_from_hash_pointer (GITypeInfo *info,
gpointer hash_pointer,
GIArgument *arg);
GI_AVAILABLE_IN_1_66
gpointer g_type_info_hash_pointer_from_argument (GITypeInfo *info,
GIArgument *arg);
G_END_DECLS G_END_DECLS