Track the `GTask`s which are still alive (not finalised) in a shared
list, and provide a secret debugging function for printing that list.
Too often when debugging apps, I have found that a ‘leaked’ object is
actually still (validly) referenced by an ongoing `GTask` which hasn’t
completed for whatever reason. Or I have found that an operation has
obviously stalled, but there are no pointers available to the `GTask`
which is stalled, because it’s being tracked as a collection of closure
pointers from some `GSource` which is hard to get to in the debugger.
It will be very useful for debugging apps, if there’s a list of all the
still alive `GTask`s somewhere. This is that list.
The code is disabled if `G_ENABLE_DEBUG` is not defined, to avoid every
`GTask` construction/finalisation imposing a global locking penalty.
To use the new list, break in `gdb` while running your app, and call
`g_task_print_alive_tasks()`, or inspect the `task_list` manually:
```
(gdb) print g_task_print_alive_tasks()
16:44:17:788 GLib-GIO 5 GTasks still alive:
• GTask 0x6100000ac740, gs_plugin_appstream_setup_async, ref count: 1, ever_returned: 0, completed: 0
• GTask 0x6100000bf940, [gio] D-Bus read, ref count: 2, ever_returned: 0, completed: 0
• GTask 0x6100000aac40, gs_plugin_loader_setup_async, ref count: 1, ever_returned: 0, completed: 0
• GTask 0x61000006d940, gs_plugin_loader_job_process_async GsPluginJobRefine, ref count: 1, ever_returned: 0, completed: 0
• GTask 0x610000118c40, [gio] D-Bus read, ref count: 2, ever_returned: 0, completed: 0
```
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
Similar to g_source_set_static_name, this avoids
strdup overhead for debug-only information in
possibly hot code paths.
We also add a macro wrapper for g_task_set_name that
uses __builtin_constant_p to decide whether to use
g_task_set_name or g_task_set_static_name.
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 gio/*.[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
g_task_set_name() was added in GLib 2.60, so only use it in the
overridden definition of g_task_set_source_tag() if the user has said
that they require GLib ≥ 2.60.
This is a follow up to commit b08bd04abe.
Signed-off-by: Philip Withnall <withnall@endlessm.com>
And improve them externally, where not otherwise set, by setting them
from the function name passed to `g_task_set_source_tag()`, if called by
third party code.
This should make profiling and debug output from GLib more useful.
Signed-off-by: Philip Withnall <withnall@endlessm.com>
Similarly to g_source_set_name(), this sets a name on a GTask for
debugging and profiling. Importantly, this name is propagated to the
GSource for idle callbacks for the GTask, ending the glorious reign of
`[gio] complete_in_idle_cb`.
The name can be queried using g_task_get_name(). Locking is avoided by
only allowing the name to be set before the GTask is used from another
thread.
Includes tests.
Signed-off-by: Philip Withnall <withnall@endlessm.com>
This can be used to query whether the task has completed, in the sense
that it has had a result set on it, and has already – or will soon –
invoke its callback function.
Notifications for this property are emitted immediately after the task’s
main callback, in the same main context as that callback. This allows
for multiple bits of code to listen for completion of the GTask, which
opens the door for blocking on cancellation of the GTask and improved
handling of ‘pending’ behaviour.
https://bugzilla.gnome.org/show_bug.cgi?id=743636
This allows compilation with clang without errors, even when
-Wformat-nonliteral is active (as long as there are no real cases of
non literal formatting).
https://bugzilla.gnome.org/show_bug.cgi?id=691608
GTask is a replacement for GSimpleAsyncResult and GIOScheduler, that
also allows for making cancellable wrappers around non-cancellable
functions (as in GThreadedResolver).
https://bugzilla.gnome.org/show_bug.cgi?id=661767
