We now guarantee that GObjects will always be allocated at least as
aligned as the basic types. If you want to put an element in your
GObject which has higher alignment requirements, we can’t guarantee it
will be aligned*. If you need it to be aligned, you’ll need to put it on
the heap (aligned appropriately), or add appropriate padding in your
GObject struct.
*Actually, GSlice will guarantee that the whole GObject is aligned to at
least the power of 2 greater than or equal to the size of the GObject,
which means any element in the GObject struct should always be
appropriate aligned if the compiler pads it appropriately. If malloc()
is used, however, it doesn’t make that guarantee, so we can’t make that
guarantee overall.
Signed-off-by: Philip Withnall <withnall@endlessm.com>
Helps: #1231
See the reasoning in the patch for why we believe GObjects *are*
(already) as aligned as the basic types.
We want to make this guarantee so that it’s guaranteed to be safe for
people to ignore -Wcast-align warnings for GObjects which contain basic
types. This typically happens with gdouble on 32-bit ARM platforms.
The checks are slightly complicated by the need to support GObjects with
custom constructors. We should expect that a custom construction
function will chain up to g_object_constructor (which calls
g_type_create_instance() as normal), but it’s possible that someone has
done something crazy and uses a custom allocator which doesn’t return
with the same alignment as GSlice. Hand them a warning in that case. If
that is true, the code which uses their custom-constructed GObject can
presumably already deal with the alignment it gets given.
Signed-off-by: Philip Withnall <withnall@endlessm.com>
Helps: #1231
The documentation sort of already said this, but it’s better to make it
explicit.
This avoids the situation where some of the weak notify callbacks for an
object have been called, and then a subsequent one resurrects the
object. Without some way of undoing the weak notifications already sent,
that would leave external state which is coupled to the object’s
lifecycle out of sync.
This arose from discussion on !2064.
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
When rendering the contents of the GLib documentation stored inside the
introspection data, a common behaviour is to take the first paragraph as
a summary of the symbol being documented.
The documentation is assumed to be in Markdown format, which means:
- paragraphs must be separated by newlines
- lines that have an indentation of four or more spaces are considered
code blocks
- lines that start with a `#` are considered titles
This means we need to slightly tweak the documentation in our sources to
ensure that it can be rendered appropriately by tools that are not
gtk-doc.
See issue: #2365
This works in the same way as g_variant_take_ref(), and for the same
reason.
Updated and Rebased by Nitin Wartkar <nitinwartkar58@gmail.com>
Closes#1112
It is cleaner to define glib_typeof() in a header included after
gversionmacros.h so we can use GLIB_VERSION_MIN_REQUIRED directly
instead of doing it everywhere glib_typeof() is used.
When included inside an `extern "C"` block, this causes build failures
that look something like:
/usr/include/c++/10/type_traits:2930:3: error: template with C linkage
2930 | template<typename _Fn, typename... _Args>
| ^~~~~~~~
../../disas/arm-a64.cc:20:1: note: ‘extern "C"’ linkage started here
20 | extern "C" {
| ^~~~~~~~~~
Commit 4273c43902 made this opt in for
projects which are defining `GLIB_VERSION_MIN_REQUIRED`, but the include
of `<type_traits>` via `gmacros.h` was not included in this. If we move
the include out to the places where `glib_typeof` is called, we can make
it covered by this macro too, and save a few consumers from FTBFSing.
That also means that, if you don't want to fix your use of the headers,
and as long as this version is sufficient for you, a quick workaround is
to define `GLIB_VERSION_MIN_REQUIRED` to `GLIB_VERSION_2_66` or lower.
Suggested by Simon McVittie.
Alternative to: https://gitlab.gnome.org/GNOME/glib/-/merge_requests/1935
Fixes: https://gitlab.gnome.org/GNOME/glib/-/issues/2331
That changes the return type of functions like g_object_ref() that can
break C++ applications like Webkit. Note that it is not an ABI break.
It must thus be opt-in the same way we did when adding this to
g_object_ref() for GNU C compilers in the first place. Unfortunately it
cannot be done directly in gmacros.h because GLIB_VERSION_2_68 is not
defined there, and gversionmacros.h cannot be included there because
there is some strict ordering in which those headers must be included.
This means that applications that does not define
GLIB_VERSION_MIN_REQUIRED will still get an API break, so we encourage
them to declare their minimum requirement to avoir such issues in the
future too.
This especially has the effect that any GWeakRefs to the object will not
necessarily be set to NULL yet if called as part of
g_object_run_dispose() and not as part of g_object_unref().
This is an API break, but no third party code should be touching
`GObject.ref_count`, let alone in a way which would be changed by the
removal of the `volatile` qualifier.
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
Helps: #600
g_has_typeof macro is wrongly in the public g_ namespace, internaly
symbols are usually in the glib_ namespace. This will also allow to
define glib_typeof differently on non-GNUC compilers (e.g. c++11
decltype).
This was mostly machine generated with the following command:
```
codespell \
--builtin clear,rare,usage \
--skip './po/*' --skip './.git/*' --skip './NEWS*' \
--write-changes .
```
using the latest git version of `codespell` as per [these
instructions](https://github.com/codespell-project/codespell#user-content-updating).
Then I manually checked each change using `git add -p`, made a few
manual fixups and dropped a load of incorrect changes.
There are still some outdated or loaded terms used in GLib, mostly to do
with git branch terminology. They will need to be changed later as part
of a wider migration of git terminology.
If I’ve missed anything, please file an issue!
Signed-off-by: Philip Withnall <withnall@endlessm.com>
When calling `g_set_object()` for a type derived from `GObject`, GCC 9.2
was giving the following strict aliasing warning:
```
../../source/malcontent/libmalcontent-ui/user-controls.c:1001:21: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
1001 | if (g_set_object (&self->user, user))
/opt/gnome/install/include/glib-2.0/gobject/gobject.h:744:33: note: in definition of macro ‘g_set_object’
744 | (g_set_object) ((GObject **) (object_ptr), (GObject *) (new_object)) \
| ^~~~~~~~~~
```
This was due to the `(GObject **)` cast.
Pass the pointer through a union to squash this warning. We already do
some size and type checks of the dereferenced type, which should catch
casual errors. The `g_object_ref()` and `g_object_unref()` calls which
subsequently happen inside the `g_set_object()` function also do some
dynamic type checks.
Add a test.
Signed-off-by: Philip Withnall <withnall@endlessm.com>
These have all been documented as deprecated for a long time, but we’ve
never had a way to programmatically mark them as deprecated. Do that
now.
This is based on the list of deprecations from the reverted commit
80fcb1bc2.
Signed-off-by: Philip Withnall <withnall@endlessm.com>
Fixes: #638
The implementation is silently discarding this anyway, and
g_object_unref() is using atomic operations. So this should be safe.
Having this here triggers -Wdiscarded-qualifiers when g_clear_pointer()
is fixed to use __typeof__().
The implementation is silently discarding this anyway, and
g_object_unref() is using atomic operations. So this should be safe.
Having this here triggers -Wdiscarded-qualifiers when g_clear_pointer()
is fixed to use __typeof__().
On gcc 4.7, we got the following error:
i686-nptl-linux-gnu-gcc --version
> i686-nptl-linux-gnu-gcc (crosstool-NG 1.20.0) 4.7.4
> $ echo '#include <glib-object.h>' | i686-nptl-linux-gnu-gcc -x c -I
staging/usr/include/glib-2.0 -I staging/usr/lib/glib-2.0/include -Wall
-Werror -c - -o /tmp/foo.o
> In file included from
staging/usr/include/glib-2.0/gobject/gbinding.h:29:0,
> from staging/usr/include/glib-2.0/glib-object.h:23,
> from <stdin>:1:
> staging/usr/include/glib-2.0/gobject/gobject.h: In function
'g_set_object':
> staging/usr/include/glib-2.0/gobject/gobject.h:725:5: error: value
computed is not used [-Werror=unused-value]
> cc1: all warnings being treated as errors
This error has been added by commit 3fae39a5d7
So enable the new g_set_object definition only if gcc >= 4.8
Fixes:
- http://autobuild.buildroot.net/results/b29a2f868438a2210873ea72f491db63175848be
Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
https://bugzilla.gnome.org/show_bug.cgi?id=795138
Weak-pointers are currently lacking g_set_object() & g_clear_object()
helpers equivalent. New functions (and macros, both are provided) are
convenient in many case, especially for the property's notify-on-set
pattern:
if (g_set_weak_pointer (...))
g_object_notify (...)
Inspired by Christian Hergert's original implementation for
gnome-builder.
https://bugzilla.gnome.org/show_bug.cgi?id=749527
The type propagation breaks the GRefPtr.h class in WebKitGTK, and in
any case existing C++ code calling the C API will need to perform an
explicit cast, as there's no automatic promotion of pointer types to
and from void*.
Tested-by: GNOME Continuous
https://bugzilla.gnome.org/show_bug.cgi?id=790697
When compiling code that includes gobject.h using GCC with the ISO
standard, the `typeof` keyword is disabled, as it's a GCC extension.
The GCC documentation recommends:
> If you are writing a header file that must work when included in
> ISO C programs, write __typeof__ instead of typeof.
Which is precisely what we're going to do.
Signed-off-by: Emmanuele Bassi <ebassi@gnome.org>
Reviewed-by: Philip Withnall <withnall@endlessm.com>
https://bugzilla.gnome.org/show_bug.cgi?id=790697
Currently, g_object_ref() and g_object_ref_sink() return a
gpointer which can mask issues when assigning to fields or
returning from a function.
To help catch these type of programming errors, we can propagate
the type of the parameter through the function call on GCC
using the typeof() C language extension.
This will cause offending code to have a warning, but will
continue to be source and binary compatible.
This is only enabled when GLIB_VERSION_MAX_ALLOWED is 2.56 or greater.
https://bugzilla.gnome.org/show_bug.cgi?id=790697
g_object_newv uses a GParameter as argument. Since GParameter
is deprecated due to this type is not introspectible,
g_object_newv is deprecated now.
https://bugzilla.gnome.org/show_bug.cgi?id=709865
g_object_new_with_properties is an alternative to g_object_newv.
The last one, takes an array of GParameter. However, GParameter
is a rarely used type and this type is not introspectible, so
it will not work properly in bindings.
https://bugzilla.gnome.org/show_bug.cgi?id=709865
Using G_STRLOC ends up embedding unique strings of the form
__FILE__:__LINE__ in the compiled binary. We can avoid these
by passing __FILE__ and __LINE__ separately when constructing
the warning text.
This probably reduces the size of the binary as __FILE__ is
likely already contained as string otherwise.
Note that for GCC 2.x this changes behavior because G_STRLOC
also contained __PRETTY_FUNCTION__.
https://bugzilla.gnome.org/show_bug.cgi?id=741654
Along the same lines as g_clear_object(), g_set_object() is a
convenience function to update a GObject pointer, handling reference
counting transparently and correctly.
Specifically, it handles the case where a pointer is set to its current
value. If handled naïvely, that could result in the object instance
being finalised. In the following code, that happens when
(my_obj == new_value) and the object has a single reference:
g_clear_object (&my_obj);
my_obj = g_object_ref (new_value);
It also simplifies boilerplate code such as set_property()
implementations, which are otherwise long and boring.
Test cases included.
https://bugzilla.gnome.org/show_bug.cgi?id=741589
g_type_is_fundamentally_a (see bug 730984) is a new API/ABI and is
marked with a version macro. We should therefore avoid its
unconditional use from G_IS_OBJECT() and G_IS_PARAM_SPEC() which are
APIs that have been around for a long time.
This prevents deprecation warnings from being emitted when these
functions are used with an older GLIB_VERSION_MAX_ALLOWED and also
prevents linking to the new ABI in that case (so that it's possible to
use the resulting binary with an older version of GLib).
https://bugzilla.gnome.org/show_bug.cgi?id=731335
Back in the far-off twentieth century, it was normal on unix
workstations for U+0060 GRAVE ACCENT to be drawn as "‛" and for U+0027
APOSTROPHE to be drawn as "’". This led to the convention of using
them as poor-man's ‛smart quotes’ in ASCII-only text.
However, "'" is now universally drawn as a vertical line, and "`" at a
45-degree angle, making them an `odd couple' when used together.
Unfortunately, there are lots of very old strings in glib, and also
lots of new strings in which people have kept up the old tradition,
perhaps entirely unaware that it used to not look stupid.
Fix this by just using 'dumb quotes' everywhere.
https://bugzilla.gnome.org/show_bug.cgi?id=700746
Add the GLIB_AVAILABLE_IN_ALL annotation to all old functions (that
haven't already been annotated with the GLIB_AVAILABLE_IN_* macros or a
deprecation macro).
If we discover in the future that we cannot use only one macro on
Windows, it will be an easy sed patch to fix that.
https://bugzilla.gnome.org/show_bug.cgi?id=688681
At least GDBus had code that had "_object" as a parameter to one of
its functions, but this clashes with the GObject macro
G_OBJECT_WARN_INVALID_PROPERTY_ID() which created a local "_object".
Since many of us cargo cult around copies of objects, let's be
defensive here and use local variable names less likely to clash with
application code.
https://bugzilla.gnome.org/show_bug.cgi?id=689377
