glib/docs/reference/girepository/migrating-gi.md
Philip Withnall 5cc5f413f5 gitypelib: Switch to refcounting
Since `GITypelib` is exposed in the public libgirepository API, it needs
to be a boxed type. So we either need to add a `copy` method to mirror
the existing `free` method, or switch to refcounting. The latter option
seems better, since a `GITypelib` contains internal state about open
`GModule`s and the semantics for copying that would be potentially
complex.

Signed-off-by: Philip Withnall <pwithnall@gnome.org>

Helps: #3155
2024-02-07 21:07:18 +00:00

4.9 KiB
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Title: Migrating from girepository-1.0 to girepository-2.0 SPDX-License-Identifier: LGPL-2.1-or-later SPDX-FileCopyrightText: 2014 GNOME Foundation

Migrating from girepository-1.0 to girepository-2.0

libgirepository was originally part of gobject-introspection, where it was prototyped for a number of years.

Now that its considered stable (for a long time), its been moved to glib in order to simplify the build process of the two modules.

As part of this move, the API version has been bumped from 1.0 to 2.0, and some fairly straightforward API changes have been made. Note that the GIR version was previously 2.0, and is now 3.0 — so the new version of libgirepository uses girepository-2.0.pc and GIRepository-3.0.typelib.

The main change between the two versions of libgirepository is that it now uses [type@GObject.TypeInstance] as the basis of its type system, rather than simple C struct aliasing. This means that [type@GIRepository.BaseInfo] instances are now reference counted using [method@GIRepository.BaseInfo.ref] and [method@GIRepository.BaseInfo.unref].

It also means that runtime cast macros such as [func@GIRepository.CALLABLE_INFO] are now available. Using these instead of simple C casts can improve the runtime type safety of your code.

Stack allocation of some [type@GIRepository.BaseInfo] subtypes is still possible, but they must now be cleared using [method@GIRepository.BaseInfo.clear] once finished with. Previously this wasnt necessary.

As part of moving the code over, the symbol prefix has changed from g_ to gi_ — this has affected every API in the library, but trivially.

The types of various function arguments have changed — for example from guint32 to size_t for most offsets. This will require minor adjustments in your code if integer type warnings are enabled.

API replacements from version 1.0 to 2.0

girepository-1.0 girepository-2.0
GI_CHECK_VERSION [func@GLib.CHECK_VERSION]
g_arg_info_get_closure [method@GIRepository.ArgInfo.get_closure_index]
g_arg_info_get_destroy [method@GIRepository.ArgInfo.get_destroy_index]
g_arg_info_get_type [method@GIRepository.ArgInfo.get_type_info]
g_arg_info_load_type [method@GIRepository.ArgInfo.load_type_info]
- [method@GIRepository.BaseInfo.ref] and [method@GIRepository.BaseInfo.unref]
g_base_info_get_type [method@GIRepository.BaseInfo.get_info_type]
g_callable_info_invoke arguments is_method and throws dropped in [method@GIRepository.CallableInfo.invoke]
g_constant_info_get_type [method@GIRepository.ConstantInfo.get_type_info]
g_field_info_get_type [method@GIRepository.FieldInfo.get_type_info]
g_object_info_get_type_init [method@GIRepository.ObjectInfo.get_type_init_function_name]
g_object_info_get_ref_function [method@GIRepository.ObjectInfo.get_ref_function_name]
g_object_info_get_unref_function [method@GIRepository.ObjectInfo.get_unref_function_name]
g_object_info_get_set_value_function [method@GIRepository.ObjectInfo.get_set_value_function_name]
g_object_info_get_get_value_function [method@GIRepository.ObjectInfo.get_get_value_function_name]
g_property_info_get_type [method@GIRepository.PropertyInfo.get_type_info]
g_registered_type_info_get_type_init [method@GIRepository.RegisteredTypeInfo.get_type_init_function_name]
g_irepository_* gi_repository_*
g_irepository_get_default Singleton object removed; create separate [class@GIRepository.Repository] instances instead
g_irepository_get_search_path and g_irepository_get_library_path Now return arrays rather than linked lists
g_irepository_enumerate_versions Now returns an array rather than a linked list
g_irepository_dump Takes structured input_filename and output_filename arguments rather than a single formatted string
g_function_invoker_destroy gi_function_invoker_clear()
g_struct_info_get_copy_function [method@GIRepository.StructInfo.get_copy_function_name]
g_struct_info_get_free_function [method@GIRepository.StructInfo.get_free_function_name]
g_type_info_get_array_length and g_type_info_get_array_fixed_size Split success and failure return values out into a new out-argument and return value
g_type_info_get_array_length [method@GIRepository.TypeInfo.get_array_length_index]
g_typelib_new_from_* All replaced with gi_typelib_new_from_bytes()
g_typelib_free [type@GIRepository.Typelib] is now a refcounted and boxed type, so use [method@GIRepository.Typelib.unref]
GI_FUNCTION_THROWS and GI_VFUNC_THROWS [method@GIRepository.CallableInfo.can_throw_gerror]
g_union_info_get_copy_function [method@GIRepository.UnionInfo.get_copy_function_name]
g_union_info_get_free_function [method@GIRepository.UnionInfo.get_free_function_name]