The user data parameters in callbacks need to be named user_data to
generate correct closure attributes in the introspection data. This
updates parameters missed in GNOME/glib!2633.
Add SPDX license (but not copyright) headers to all files which follow a
certain pattern in their existing non-machine-readable header comment.
This commit was entirely generated using the command:
```
git ls-files glib/*.[ch] | xargs perl -0777 -pi -e 's/\n \*\n \* This library is free software; you can redistribute it and\/or\n \* modify it under the terms of the GNU Lesser General Public/\n \*\n \* SPDX-License-Identifier: LGPL-2.1-or-later\n \*\n \* This library is free software; you can redistribute it and\/or\n \* modify it under the terms of the GNU Lesser General Public/igs'
```
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
Helps: #1415
The g_once() function exists to call a callback function exactly once,
and to block multiple contending threads on its completion, then to
return its return value to all of them (so they all see the same value).
The full implementation of g_once() (in g_once_impl()) uses a mutex and
condition variable to achieve this, and is needed in the contended case,
where multiple threads need to be blocked on completion of the callback.
However, most of the times that g_once() is called, the callback will
already have been called, and it just needs to establish that it has
been called and to return the stored return value.
Previously, a fast path was used if we knew that memory barriers were
not needed on the current architecture to safely access two dependent
global variables in the presence of multi-threaded access. This is true
of all sequentially consistent architectures.
Checking whether we could use this fast path (if
`G_ATOMIC_OP_MEMORY_BARRIER_NEEDED` was *not* defined) was a bit of a
pain, though, as it required GLib to know the memory consistency model
of every architecture. This kind of knowledge is traditionally a
compiler’s domain.
So, simplify the fast path by using the compiler-provided atomic
intrinsics, and acquire-release memory consistency semantics, if they
are available. If they’re not available, fall back to always locking as
before.
We definitely need to use `__ATOMIC_ACQUIRE` in the macro implementation
of g_once(). We don’t actually need to make the `__ATOMIC_RELEASE`
changes in `gthread.c` though, since locking and unlocking a mutex
guarantees to insert a full compiler and hardware memory barrier
(enforcing sequential consistency). So the `__ATOMIC_RELEASE` changes
are only in there to make it obvious what stores are logically meant to
match up with the `__ATOMIC_ACQUIRE` loads in `gthread.h`.
Notably, only the second store (and the first load) has to be atomic.
i.e. When storing `once->retval` and `once->status`, the first store is
normal and the second is atomic. This is because the writes have a
happens-before relationship, and all (atomic or non-atomic) writes
which happen-before an atomic store/release are visible in the thread
doing an atomic load/acquire on the same atomic variable, once that load
is complete.
References:
* https://preshing.com/20120913/acquire-and-release-semantics/
* https://gcc.gnu.org/onlinedocs/gcc-9.2.0/gcc/_005f_005fatomic-Builtins.html
* https://gcc.gnu.org/wiki/Atomic/GCCMM/AtomicSync
* https://en.cppreference.com/w/cpp/atomic/memory_order#Release-Acquire_ordering
Signed-off-by: Philip Withnall <withnall@endlessm.com>
Fixes: #1323
This reverts commit c0146be3a4.
The revert was originally added because the original change broke
gnome-build-meta. Now that the problem has been diagnosed, the original
commit can be fixed — see the commit which follows this one.
See: !1487
The public functions exposed as static inlines currently don't have
annotations to describe when they were introduced. This means that
compiling this file:
#include <glib.h>
void foo (void)
{
g_rec_mutex_locker_new (NULL);
}
with:
gcc -c test.c \
-I/tmp/glib/include/glib-2.0 \
-I/tmp/glib/lib/x86_64-linux-gnu/glib-2.0/include \
-Werror \
-DGLIB_VERSION_MAX_ALLOWED=GLIB_VERSION_2_28 \
-DGLIB_VERSION_MIN_REQUIRED=GLIB_VERSION_2_28
will not produce any error message, despite using
`g_rec_mutex_locker_new`, a function that was introduced after 2.28.
This patch adds some annotations to all the publicly exposed static
inline functions I could find.
I could not use the existing G_AVAILABLE* macros, because they may
expand to `extern`. This would then clash with the `static` keyword and
produce:
../glib/gthread.h:397:1: error: multiple storage classes in declaration specifiers
397 | static inline GRecMutexLocker *
| ^~~~~~
So I opted for adding a new set of macros,
GLIB_AVAILABLE_STATIC_INLINE_IN_2_XY.
With this patch applied, the example from above produces the expected
warning:
test.c: In function ‘foo’:
test.c:5:3: error: ‘g_rec_mutex_locker_new’ is deprecated: Not available before 2.60 [-Werror=deprecated-declarations]
5 | g_rec_mutex_locker_new (NULL);
| ^~~~~~~~~~~~~~~~~~~~~~
In file included from /tmp/glib/include/glib-2.0/glib/gasyncqueue.h:32,
from /tmp/glib/include/glib-2.0/glib.h:32,
from test.c:1:
/tmp/glib/include/glib-2.0/glib/gthread.h:398:1: note: declared here
398 | g_rec_mutex_locker_new (GRecMutex *rec_mutex)
| ^~~~~~~~~~~~~~~~~~~~~~
With a trivial file that just includes glib.h:
#include <glib.h>
Compiled with:
gcc -c test.c \
-I /tmp/glib/include/glib-2.0/ \
-I /tmp/glib/lib/x86_64-linux-gnu/glib-2.0/include \
-DGLIB_VERSION_MAX_ALLOWED=GLIB_VERSION_2_28 \
-DGLIB_VERSION_MIN_REQUIRED=GLIB_VERSION_2_28 \
-fmax-errors=1 \
-Werror
We get:
In file included from /tmp/glib/include/glib-2.0/glib/gasyncqueue.h:32,
from /tmp/glib/include/glib-2.0/glib.h:32,
from test.c:1:
/tmp/glib/include/glib-2.0/glib/gthread.h: In function ‘g_rec_mutex_locker_new’:
/tmp/glib/include/glib-2.0/glib/gthread.h:396:3: error: ‘g_rec_mutex_lock’ is deprecated: Not available before 2.32 [-Werror=deprecated-declarations]
396 | g_rec_mutex_lock (rec_mutex);
| ^~~~~~~~~~~~~~~~
/tmp/glib/include/glib-2.0/glib/gthread.h:196:17: note: declared here
196 | void g_rec_mutex_lock (GRecMutex *rec_mutex);
| ^~~~~~~~~~~~~~~~
compilation terminated due to -fmax-errors=1.
The problem is that the code in the static inline functions uses
g_rec_mutex_lock, introduced after 2.28. This code is compiled
regardless of if it's actually used or not.
Suppress the warning by using G_GNUC_BEGIN_IGNORE_DEPRECATIONS /
G_GNUC_END_IGNORE_DEPRECATIONS. There are precedents for doing that,
for example g_main_context_pusher_new in gmain.h.
Tested by building with all variations of GLIB_VERSION_MIN_REQUIRED /
GLIB_VERSION_MAX_ALLOWED:
for i in $(seq 26 2 64); do
gcc -c test.c \
-I/tmp/glib/include/glib-2.0 \
-I/tmp/glib/lib/x86_64-linux-gnu/glib-2.0/include \
-DGLIB_VERSION_MAX_ALLOWED=GLIB_VERSION_2_$i \
-DGLIB_VERSION_MIN_REQUIRED=GLIB_VERSION_2_$i \
-fmax-errors=1 \
-Werror
done
Fixes: #2094
794c1a30bc "macro wrappers for
g_once_init_enter/leave" added this line (whose intent is unclear to me).
<http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p1152r4.html>
"Deprecating volatile" (scheduled for inclusion in C++20) will make the
assignment expression
*(location) = (result)
deprecated when the LHS is of (non-class) volatile type, which is the case when
g_once_init_leave is expanded as part of e.g. G_DEFINE_TYPE_WITH_CODE (in
gobject/gtype.h), where location is a pointer to some
static volatile gsize g_define_type_id__volatile = 0;
Recent Clang trunk emits -Wdeprecated-volatile for it under -std=c++2a since
<https://github.com/llvm/llvm-project/commit/
4a6861a7e5b59be24a09b8b9782255d028e7aade> "[c++20] P1152R4: warn on any
simple-assignment to a volatile lvalue".
The fix is to make the assignment expression a discared-value expression by
casting it to void (which in turn requires casting the second branch of the
surrounding conditional expression to void, too; not sure what the top-level
cast to void was intended for, and whether it would still be needed under
certain circumstances).
When compiling a program using glib with -Wzero-as-null-pointer-constant
warnings enabled, the compiler warns about this type check in the
g_once_init_enter macro. Fix by replacing "0" with "NULL".
All glib/*.{c,h} files have been processed, as well as gtester-report.
12 of those files are not licensed under LGPL:
gbsearcharray.h
gconstructor.h
glibintl.h
gmirroringtable.h
gscripttable.h
gtranslit-data.h
gunibreak.h
gunichartables.h
gunicomp.h
gunidecomp.h
valgrind.h
win_iconv.c
Some of them are generated files, some are licensed under a BSD-style
license and win_iconv.c is in the public domain.
Sub-directories inside glib/:
deprecated/: processed in a previous commit
glib-mirroring-tab/: already LGPLv2.1+
gnulib/: not modified, the code is copied from gnulib
libcharset/: a copy
pcre/: a copy
tests/: processed in a previous commit
https://bugzilla.gnome.org/show_bug.cgi?id=776504
gmem.h and gthread.h made use of the inline keyword, that is not available
on all compilers in C-mode, causing builds to break on such compilers.
Include glib/gutils.h which handles the inline issue, in place of
glib/gtypes.h if applicable, which is included quite early on by
glib/gutils.h.
https://bugzilla.gnome.org/show_bug.cgi?id=744190
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
Switch GCond to using monotonic time for timed waits by introducing a
new API based on monotonic time in a gint64: g_cond_wait_until().
Deprecate the old API based on wallclock time in a GTimeVal.
Fix up the gtk-doc for GCond while we're at it: update the examples to
use static-allocated GCond and GMutex and clarify some things a bit.
Also explain the rationale behind using an absolute time instead of a
relative time.
We'll hold out on this until someone has a really convincing reason for
why they need to control the stack size.
If we do decide to add it back, it should probably have a name like
_new_with_stack_size(), not _full().
And remove the 'joinable' argument from g_thread_new() and
g_thread_new_full().
Change the wording in the docs. Clarify expectations for
(deprecated) g_thread_create().
Give the macro wrapper treatment to g_once_init_enter() and leave() in
the same style that we did for gatomic.
It is now possible to use these macros with any pointer-sized object,
and not just gsize. The leave() macro ensures that the initialisation
result is a compatible type with the pointer that it is being written
to.
Just like with gatomic, there could be problems caused by use of (void*)
casts. We'll see how that goes, and reevaluate if necessary.
https://bugzilla.gnome.org/show_bug.cgi?id=660743
Add a little bit more room in the ABI for our synchronisation primatives
since we're going to need it when we add native implementations on
Linux.
Also: rename the pointer field and add /*< private >*/ annotations.
All locks are now zero-initialised, so we can drop the G_*_INIT macros
for them.
Adjust various users around GLib accordingly and change the docs.
https://bugzilla.gnome.org/show_bug.cgi?id=659866
Modify the POSIX implementation of the synchronisation primatives to use
the same ABI as Windows: one pointer for each type.
This frees us from having to #include <pthread.h> and avoids the problem
with pthread_rwlock_t not being defined under certain compiler defines.
A few more changes are expected to the ABI -- they will be committed
separately.
https://bugzilla.gnome.org/show_bug.cgi?id=659866
This commit moves GStaticPrivate, g_thread_foreach and all
related functions and variables to gthread-deprecated.c. We
introduce some internal API to make this possible.
g_thread_foreach is not a very useful function, since there is
virtually nothing you can do with a GThread*, and implementing
it requires us to keep a list of threads around.
GStaticPrivate has been made redundant by adding comparable
capabilities to GPrivate.
https://bugzilla.gnome.org/show_bug.cgi?id=660635
Deprecate both g_thread_create functions and add
g_thread_new() and g_thread_new_full(). The new functions
expect a name for the thread.
Change GThreadPool, GMainContext and GDBus to create named threads.
https://bugzilla.gnome.org/show_bug.cgi?id=660635
Take out the half-private g_private_init() stuff and replace it with a
G_PRIVATE_INIT macro that allows specifying a GDestroyNotify.
Expose the GPrivate structure in a public header.
Add a g_private_replace() to (sort of) match the functionality of
g_static_mutex_set().
Improve the documentation.
Deprecate g_private_new().
