This is so that cogl-trace.h can start using things from cogl-macros.h,
and so that it doesn't leak cogl-config.h into the world, while exposing
it to e.g. gnome-shell so that it can make use of it as well. There is
no practical reason why we shouldn't just include cogl-trace.h via
cogl.h as we do with everything else.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/1059
Public functions in C should be declared before they are defined, and
often compilers warn you if you haven't:
```
../cogl/cogl/cogl-trace.c:237:1: warning: no previous prototype for
‘cogl_set_tracing_enabled_on_thread_with_fd’ [-Wmissing-prototypes]
cogl_set_tracing_enabled_on_thread_with_fd (void *data,
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../cogl/cogl/cogl-trace.c:245:1: warning: no previous prototype for
‘cogl_set_tracing_enabled_on_thread’ [-Wmissing-prototypes]
cogl_set_tracing_enabled_on_thread (void *data,
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../cogl/cogl/cogl-trace.c:253:1: warning: no previous prototype for
‘cogl_set_tracing_disabled_on_thread’ [-Wmissing-prototypes]
cogl_set_tracing_disabled_on_thread (void *data)
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
```
In this case the function declarations were not included because
`HAVE_TRACING` isn't defined. But we should still include `cogl-trace.h`
because it handles the case of `HAVE_TRACING` not being defined and
correctly still declares the functions defined in `cogl-trace.c`.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/650
Add the ability to add tracing instrumentation to the code. When
enabled, trace entries will generate a file with timing information
that will be processable by sysprof for generating visualization of
traces over time.
While enabled by default at compile time, it is possible to disable the
expansion of the macros completely by passing --disable-tracing to
./configure.
Tracing is so far only actually done if actually enabled on explicitly
specified threads.
This will be used by Mutter passing the write end of a pipe, where the
read end is sent to Sysprof itself via the D-Bus method 'Capture()'.
By passing that, we have to detect EPIPE that is sent when Sysprof stops
recording. Fortunately, we already ignore the signal at meta_init(), so
no need to add a custom signal handler.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/197
