Unbinding can happen from one thread while a property notification is
being handled concurrently in another one.
To solve this, introduce a reference counter for the transform function
that ensures that it always stays valid while in use and protect access
to the one stored inside the binding with the unbind mutex.
It's possible for g_binding_unbind() to be called at the same time as
one (or both) of source and target are being finalized. The resulting
unbinding needs to be protected with a mutex to ensure that it only
happens exactly once.
As the first reference is owned by both weak notifies and the caller of
g_object_bind_property(), additional indirections are needed to ensure that
unreffing the first reference after creation still unbinds the binding
as before. This seems to be a common code pattern and how this was
intended to be used, but is only safe in single-threaded contexts as it
relies on both the source and target object to be still alive.
Add a lot of comments to the code about all these dependencies and a
couple of assertions to ensure they hold valid.
Also document that inconsistent reference ownership handling of
g_binding_unbind() that makes it unfit for automatically generated
language bindings.
It still works, and deprecating it would be quite disruptive (as it’s
used in headers), so amend the documentation to point people to
`G_NORETURN` instead.
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
Helps: #994
gobject/gobject.c: In function ‘g_object_new_internal’:
gobject/gobject.c:1962:25: error: comparison of integer expressions of different signedness: ‘gint’ {aka ‘int’} and ‘guint’ {aka ‘unsigned int’}
1962 | for (j = 0; j < n_params; j++)
| ^
gobject/gobject.c:1989:21: error: comparison of integer expressions of different signedness: ‘gint’ {aka ‘int’} and ‘guint’ {aka ‘unsigned int’}
1989 | for (i = 0; i < n_params; i++)
| ^
gobject/gobject.c: In function ‘g_object_new_with_custom_constructor’:
gobject/gobject.c:1836:21: error: comparison of integer expressions of different signedness: ‘gint’ {aka ‘int’} and ‘guint’ {aka ‘unsigned int’}
1836 | for (j = 0; j < n_params; j++)
| ^
gobject/gobject.c:1914:17: error: comparison of integer expressions of different signedness: ‘gint’ {aka ‘int’} and ‘guint’ {aka ‘unsigned int’}
1914 | for (i = 0; i < n_params; i++)
| ^
gobject/gobject.c: In function ‘g_object_class_install_properties’:
gobject/gobject.c:766:17: error: comparison of integer expressions of different signedness: ‘gint’ {aka ‘int’} and ‘guint’ {aka ‘unsigned int’}
766 | for (i = 1; i < n_pspecs; i++)
| ^
gobject/gtype.c: In function ‘g_type_interface_add_prerequisite’:
gobject/gtype.c:1607:21: error: comparison of integer expressions of different signedness: ‘guint’ {aka ‘unsigned int’} and ‘int’
1607 | for (i = 0; i < prerequisite_node->n_supers + 1; i++)
| ^
The problem occurs because we keep a pointer inside the allocated block,
instead of a pointer to the start of the block. This memory exists for
the lifetime of the application, so let's silence it.
This is probably abuse of VALGRIND_MALLOCLIKE_BLOCK(), which is really
intended for use in memory allocators, but gtype.c already uses it in
two other places, and it's a practical solution. I wrote another larger
fix for this issue that involves keeping an array of extra pointers when
running under valgrind. This is simpler.
Fix suggested by Philip Withnall
```
==180238== 16 bytes in 1 blocks are possibly lost in loss record 3,078 of 16,075
==180238== at 0x483BB1A: calloc (vg_replace_malloc.c:762)
==180238== by 0x5489495: g_malloc0 (gmem.c:132)
==180238== by 0x5489754: g_malloc0_n (gmem.c:364)
==180238== by 0x53FDBEE: type_set_qdata_W (gtype.c:3722)
==180238== by 0x53FDEE8: type_add_flags_W (gtype.c:3787)
==180238== by 0x53FC348: g_type_register_fundamental (gtype.c:2662)
==180238== by 0x53D969B: _g_enum_types_init (genums.c:124)
==180238== by 0x53FF058: gobject_init (gtype.c:4432)
==180238== by 0x53FF082: gobject_init_ctor (gtype.c:4493)
==180238== by 0x4010F29: call_init.part.0 (dl-init.c:72)
==180238== by 0x4011030: call_init (dl-init.c:30)
==180238== by 0x4011030: _dl_init (dl-init.c:119)
==180238== by 0x4002149: ??? (in /usr/lib64/ld-2.30.so)
```
Fixes#2076
The problem occurs because we keep a pointer inside the allocated block,
instead of a pointer to the start of the block:
```
==180238== 16 bytes in 1 blocks are possibly lost in loss record 3,086 of 16,075
==180238== at 0x483980B: malloc (vg_replace_malloc.c:309)
==180238== by 0x548942C: g_malloc (gmem.c:102)
==180238== by 0x54A4748: g_slice_alloc (gslice.c:1025)
==180238== by 0x53D0AAF: freelist_alloc (gatomicarray.c:77)
==180238== by 0x53D0B85: _g_atomic_array_copy (gatomicarray.c:133)
==180238== by 0x53F8E6D: iface_node_set_offset_L (gtype.c:1347)
==180238== by 0x53F91F1: type_node_add_iface_entry_W (gtype.c:1444)
==180238== by 0x53F93DF: type_add_interface_Wm (gtype.c:1477)
==180238== by 0x53FC946: g_type_add_interface_static (gtype.c:2852)
==180238== by 0x4A3D53A: gtk_menu_shell_accessible_get_type_once (gtkmenushellaccessible.c:26)
==180238== by 0x4A3D495: gtk_menu_shell_accessible_get_type (gtkmenushellaccessible.c:26)
==180238== by 0x4C8AC44: gtk_menu_shell_class_init (gtkmenushell.c:424)
```
Note we cannot use VALGRIND_FREELIKE_BLOCK() in freelist_free() because we
have not actually freed the FreeListNode and need to dereference it in
freelist_alloc() to decide whether to reuse the block. That would result
in a use-after-free warning before we would get a chance to call
VALGRIND_MALLOCLIKE_BLOCK() in the reuse path.
Also note that this free list only ever grows: it never shrinks for the
lifetime of the application, so nothing here will ever be truely freed,
although unused elements are eligible for reuse.
Fix suggested by Philip Withnall
Related: #2076
For URIs produced in string form, the path should be normalized and port
omitted when the default one is used. When querying the path and port of
a GUri (using getters or g_uri_split()) the normalized path and the
default port should be returned when they were omitted in the parsed URI.
Closes#2257
`g_time_zone_new_identifier()` returns NULL in the FreeBSD test setup,
presumably because `TZ` isn’t set.
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
Helps: #553
gobject/gtype.c: In function ‘type_node_add_iface_entry_W’:
gobject/gtype.c:1379:21: error: comparison of integer expressions of different signedness: ‘guint’ {aka ‘unsigned int’} and ‘int’
1379 | for (i = 0; i < num_entries; i++)
| ^
gobject/gtype.c: In function ‘lookup_iface_entry_I’:
gobject/gtype.c:599:17: error: comparison of integer expressions of different signedness: ‘int’ and ‘long unsigned int’
599 | if (index < IFACE_ENTRIES_N_ENTRIES (entries))
| ^
gobject/gatomicarray.h:51:8: note: in definition of macro ‘G_ATOMIC_ARRAY_DO_TRANSACTION’
51 | {_C_;} \
| ^~~
Use `g_time_zone_new_identifier()` instead so you can get error
checking.
Adapt the tests to match.
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
Helps: #553
It doesn’t seem to be possible to use `only:changes` from a branch
pipeline extending `.only-default` and have it correctly trigger when
`*.sh` or `*.py` files are modified.
We possibly need to convert all our pipelines to be merge-request-only,
but that’s an avenue I’ve been down before and I couldn’t get it to
work. Using
[`workflow:rules`](https://docs.gitlab.com/ee/ci/yaml/README.html#workflowrules)
might fix that, but I don’t have time to rework the entire CI to use
that now.
So in the meantime, move the SH and Py checks into the existing
style-check job so we’re not always spinning up two additional container
instances on every merge request.
See !1743.
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
Spotted by shellcheck (warning SC1117): `\e` is not an actual escape
sequence, so it’s interpreted as `\\e`. Best make that explicit.
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
Half of the references to `init_state` in `gtype.c` already correctly
accessed it atomically, but a couple didn’t. Drop the `volatile`
qualifier from its declaration, as that’s not necessary for atomic
access.
Note that this is the `init_state` in `TypeData`, *not* the `init_state`
in `IFaceEntry`.
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
Helps: #600
In the Windows destructor list, consistently access
`g_private_destructors` using atomic primitives.
`g_atomic_pointer_compare_and_exchange()` should be equivalent to
`InterlockedCompareExchangePointer()`, but is a bit more understandable
in a general GLib context, and pairs with `g_atomic_pointer_get()`. (I
can’t find a Windows API equivalent for that.)
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
Helps: #600
