gutils.[hc] is a bit of a grab bag, so lets start cleaning
things up by moving all the environment-related functions
into separate genviron.[hc] files.
The private _g_getenv_nomalloc has been moved to its sole caller.
When spawning a child process, it is not safe to call setenv() before
the fork() (because setenv() isn't thread-safe), but it's also not
safe to call it after the fork() (because it's not async-signal-safe).
So the only safe way to alter the environment for a child process from
a threaded program is to pass a fully-formed envp array to
exec*/g_spawn*/etc.
So, add g_environ_getenv(), g_environ_setenv(), and
g_environ_unsetenv(), which act like their namesakes, but work on
arbitrary arrays rather than working directly on the environment.
http://bugzilla.gnome.org/show_bug.cgi?id=659326
01ed78d525 introduced assertion checks for
creating a main context, forking, and attempting to use the main context
from the child side of the fork.
Some code (such as gnome-keyring-daemon) daemonise after calling
GMainContext. That's probably still mostly safe since we still only
have one side of the fork touching the context afterwards.
This use case is still troubling, however, since if any worker threads
have been created at the time of the fork(), we could end up in the
classic situation of leaving some mutexes in a locked state when the
other threads disappear from the copy of the image that the child gets.
This will require some deeper thinking...
Some code using GLib (gnome-keyring-daemon, for example) assumes that
they can catch signals by masking them out in the main thread and
calling sigwait() from a worker.
The problem is that our new worker thread catches the signals before
sigwait() has a chance and the default action occurs (typically
resulting in program termination).
If we mask all the signals in our worker, then this can't happen.
With search gaining traction as being the preferred way to locate
applications, the existing .desktop file fields meant for browsing
often produce insufficient results.
gnome-control-center introduced a custom X-GNOME-Keywords field for
that purpose, which we plan to support in gnome-shell as well.
https://bugzilla.gnome.org/show_bug.cgi?id=661763
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.
Hide the definition of struct _GThread in gthreadprivate.h for now.
This is possibly an API break -- although the structure contents were
undocumented and it was not safe to access them in a meaningful way,
someone may have tried to do it anyway. We'll leave it here for a while
to see if it causes any problems.
Avoid merging its contents with GRealThread for now, just incase we need
to expose it again.
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().
GThread is freed using some very slightly confusing logic: if the thread
was created 'joinable', then the structure is freed after the join()
call succeeds (since we know the thread has exited). If the thread was
not created 'joinable' then the free is when the thread quits (since we
know 'join' will not be called later).
Move to a straight ref-counting system: 1 ref owned by the thread and 1
extra ref if the thread is joinable. Both thread quit and joining will
decrease the refcount by 1.
Make the POSIX backend a little bit more like the win32 one in terms of
how we deal with joinability.
Calling g_system_thread_join() is now optional, and
g_system_thread_wait() can be safely called by multiple threads.
There is no longer any internal concept of joinability.
Merge the GThreadData with the GThreadWin32 struct. Drop the extra TLS
variable.
Close the handle on _free(), which means that there is no leak if
g_system_thread_join() isn't called.
Remove all internal concept of joinability.
Keep track of if we created a thread for ourselves or if the GThread*
was allocated in response to g_thread_self() on a previously-unknown
thread.
Only call g_system_thread_free() in the first case.
Wrap GRealThread in a GThreadPosix that includes its own pthread_t field
called "system_thread" and use that instead of the generic field in
GRealThread.
