[libvirt PATCH 1/6] Revert "docs: Drop glib-adoption.rst"
Ján Tomko
jtomko at redhat.com
Thu Sep 24 12:28:35 UTC 2020
Cleaning up after Andrea as he requested:
https://www.redhat.com/archives/libvir-list/2020-May/msg00405.html
This reverts commit 842d3712ed612f213b454e610cc7ff9db2321803
---
docs/glib-adoption.rst | 96 ++++++++++++++++++++++++++++++++++++++++++
docs/hacking.rst | 1 +
2 files changed, 97 insertions(+)
create mode 100644 docs/glib-adoption.rst
diff --git a/docs/glib-adoption.rst b/docs/glib-adoption.rst
new file mode 100644
index 0000000000..62ddd7c61d
--- /dev/null
+++ b/docs/glib-adoption.rst
@@ -0,0 +1,96 @@
+=====================
+Adoption of GLib APIs
+=====================
+
+Libvirt has adopted use of the `GLib
+library <https://developer.gnome.org/glib/stable/>`__. Due to
+libvirt's long history of development, there are many APIs in
+libvirt, for which GLib provides an alternative solution. The
+general rule to follow is that the standard GLib solution will be
+preferred over historical libvirt APIs. Existing code will be
+ported over to use GLib APIs over time, but new code should use
+the GLib APIs straight away where possible.
+
+The following is a list of libvirt APIs that should no longer be
+used in new code, and their suggested GLib replacements:
+
+``VIR_ALLOC``, ``VIR_REALLOC``, ``VIR_RESIZE_N``, ``VIR_EXPAND_N``, ``VIR_SHRINK_N``, ``VIR_FREE``, ``VIR_APPEND_ELEMENT``, ``VIR_INSERT_ELEMENT``, ``VIR_DELETE_ELEMENT``
+ Prefer the GLib APIs ``g_new0``/``g_renew``/ ``g_free`` in most
+ cases. There should rarely be a need to use
+ ``g_malloc``/``g_realloc``. Instead of using plain C arrays, it
+ is preferrable to use one of the GLib types, ``GArray``,
+ ``GPtrArray`` or ``GByteArray``. These all use a struct to
+ track the array memory and size together and efficiently
+ resize. **NEVER MIX** use of the classic libvirt memory
+ allocation APIs and GLib APIs within a single method. Keep the
+ style consistent, converting existing code to GLib style in a
+ separate, prior commit.
+``virStrerror``
+ The GLib ``g_strerror()`` function should be used instead,
+ which has a simpler calling convention as an added benefit.
+
+The following libvirt APIs have been deleted already:
+
+``VIR_AUTOPTR``, ``VIR_AUTOCLEAN``, ``VIR_AUTOFREE``
+ The GLib macros ``g_autoptr``, ``g_auto`` and ``g_autofree``
+ must be used instead in all new code. In existing code, the
+ GLib macros must never be mixed with libvirt macros within a
+ method, nor should they be mixed with ``VIR_FREE``. If
+ introducing GLib macros to an existing method, any use of
+ libvirt macros must be converted in an independent commit.
+``VIR_DEFINE_AUTOPTR_FUNC``, ``VIR_DEFINE_AUTOCLEAN_FUNC``
+ The GLib macros ``G_DEFINE_AUTOPTR_CLEANUP_FUNC`` and
+ ``G_DEFINE_AUTO_CLEANUP_CLEAR_FUNC`` must be used in all new
+ code. Existing code should be converted to the new macros where
+ relevant. It is permissible to use ``g_autoptr``, ``g_auto`` on
+ an object whose cleanup function is declared with the libvirt
+ macros and vice-versa.
+``VIR_AUTOUNREF``
+ The GLib macros ``g_autoptr`` and
+ ``G_DEFINE_AUTOPTR_CLEANUP_FUNC`` should be used to manage
+ autoclean of virObject classes. This matches usage with GObject
+ classes.
+``VIR_STRDUP``, ``VIR_STRNDUP``
+ Prefer the GLib APIs ``g_strdup`` and ``g_strndup``.
+
++-------------------------------+--------------------------------------+-------------------------------------------+
+| deleted version | GLib version | Notes |
++===============================+======================================+===========================================+
+| ``VIR_AUTOPTR`` | ``g_autoptr`` | |
++-------------------------------+--------------------------------------+-------------------------------------------+
+| ``VIR_AUTOCLEAN`` | ``g_auto`` | |
++-------------------------------+--------------------------------------+-------------------------------------------+
+| ``VIR_AUTOFREE`` | ``g_autofree`` | The GLib version does not use parentheses |
++-------------------------------+--------------------------------------+-------------------------------------------+
+| ``VIR_AUTOUNREF`` | ``g_autoptr`` | The cleanup function needs to be defined |
++-------------------------------+--------------------------------------+-------------------------------------------+
+| ``VIR_DEFINE_AUTOPTR_FUNC`` | ``G_DEFINE_AUTOPTR_CLEANUP_FUNC`` | |
++-------------------------------+--------------------------------------+-------------------------------------------+
+| ``VIR_DEFINE_AUTOCLEAN_FUNC`` | ``G_DEFINE_AUTO_CLEANUP_CLEAR_FUNC`` | |
++-------------------------------+--------------------------------------+-------------------------------------------+
+| ``VIR_STEAL_PTR`` | ``g_steal_pointer`` | ``a = f(&b)`` instead of ``f(a, b)`` |
++-------------------------------+--------------------------------------+-------------------------------------------+
+| ``VIR_RETURN_PTR`` | ``return g_steal_pointer`` | |
++-------------------------------+--------------------------------------+-------------------------------------------+
+| ``ARRAY_CARDINALITY`` | ``G_N_ELEMENTS`` | |
++-------------------------------+--------------------------------------+-------------------------------------------+
+| ``ATTRIBUTE_FALLTHROUGH`` | ``G_GNUC_FALLTHROUGH`` | |
++-------------------------------+--------------------------------------+-------------------------------------------+
+| ``ATTRIBUTE_FMT_PRINTF`` | ``G_GNUC_PRINTF`` | |
++-------------------------------+--------------------------------------+-------------------------------------------+
+| ``ATTRIBUTE_NOINLINE`` | ``G_GNUC_NO_INLINE`` | |
++-------------------------------+--------------------------------------+-------------------------------------------+
+| ``ATTRIBUTE_NORETURN`` | ``G_GNUC_NORETURN`` | |
++-------------------------------+--------------------------------------+-------------------------------------------+
+| ``ATTRIBUTE_RETURN_CHECK`` | ``G_GNUC_WARN_UNUSED_RESULT`` | |
++-------------------------------+--------------------------------------+-------------------------------------------+
+| ``ATTRIBUTE_SENTINEL`` | ``G_GNUC_NULL_TERMINATED`` | |
++-------------------------------+--------------------------------------+-------------------------------------------+
+| ``ATTRIBUTE_UNUSED`` | ``G_GNUC_UNUSED`` | |
++-------------------------------+--------------------------------------+-------------------------------------------+
+| ``VIR_STRDUP`` | ``g_strdup`` | |
++-------------------------------+--------------------------------------+-------------------------------------------+
+| ``VIR_STRNDUP`` | ``g_strndup`` | |
++-------------------------------+--------------------------------------+-------------------------------------------+
+| ``virStrerror`` | ``g_strerror`` | |
++-------------------------------+--------------------------------------+-------------------------------------------+
diff --git a/docs/hacking.rst b/docs/hacking.rst
index 858dd2dfc1..cd009c4c73 100644
--- a/docs/hacking.rst
+++ b/docs/hacking.rst
@@ -74,4 +74,5 @@ you also take a look at the following documents:
- `Programming languages <programming-languages.html>`__
- `Developer tooling <developer-tooling.html>`__
- `Advanced test suite usage <advanced-tests.html>`__
+- `Adoption of GLib APIs <glib-adoption.html>`__
- `Committer guidelines <committer-guidelines.html>`__
--
2.26.2
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