In contrast to the already existing ScreenClose hook, this one is
called *after* the driver's CloseScreen() proc. That's required for
some extensions (eg. damage) where drivers still need to call in
inside of their CloseScreen procs.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Right now, extensions that need to be called after the CreateScreenResources
proc had been run, must wrap the screen proc vector directly (all of them
forming kind of daisy chain), and so - when called - temporarily restore the
previous one, call it, wrap again, and if the call was successful finally
doing it's own stuff. (same is done for many other procs)
While that approach is looking nice and elegant on the drawing board, it's
complicated, dangerous like a chainsaw and makes debugging hard, leading to
pretty blurred API borders.
Instead introducing a simple approach for letting extension hook into a
post-CreateScreenResources callback list safely, w/o having to care much
about side effects with the call chain. Extensions now can simply register
their business logic and get called back - w/o ever having to mess with the
ScreenRec's internal structures.
Note that these hooks are executed *AFTER* the original CreateScreenResources()
proc had been called SUCCESSFULLY (returned TRUE), so callees can rely on
the DDX/driver had already done it's job.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Right now, extension specific pixmap destruction procedures are implemented
by wrapping the ScreenRec's DestroyPixmap() proc pointer: the extensions are
storing the original pointer in their private data and putting in their own one.
On each call, their proc restores the original one, calls it, and switches back
again. When multiple extensions doing so, they're forming a kind of daisy chain.
(the same is done for lots of other procs)
While that approach is looking nice and elegant on the drawing board, it's
complicated, dangerous like a chainsaw and makes debugging hard, leading to
pretty blurred API borders.
It's even getting worse: the proc also has to do ref counting, and only destroy
the pixmap if refconter reaching zero - that's all done in the individual screen
drivers. Therefore, all extensions must check for refcnt == 1, in order to know
when to really act.
This commit introduces a simple approach for letting extension hook into the
pixmap destruction safely, w/o having to care much about side effects with
the call chain. Extensions now can simply register their destructor proc
(and an opaque pointer) and get called back - w/o ever having to mess with
the ScreenRec's internal structures.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Right now, extension specific actions on screen closing implemented by wrapping
the ScreenRec's PositionWindow() proc pointer: the extensions are storing the
original pointer in their private data and putting in their own one. On each
call, their proc restores the original one, calls it, and switches back again.
When multiple extensions doing so, they're forming a kind of daisy chain.
(the same is done for lots of other procs)
While that approach is looking nice and elegant on the drawing board, it's
complicated, dangerous like a chainsaw and makes debugging hard, leading to
pretty blurred API borders.
This commit introduces a simple approach for letting extension hook into the
screen closing path safely, w/o having to care much about side effects with
the call chain. Extensions now can simply register their hook proc (and an
opaque pointer) and get called back - w/o ever having to mess with the
ScreenRec's internal structures. These hooks are called before the original
vector (usually handled by DDX/screen driver directly) is called.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Wrapping ScreenRec's function pointers is problematic for many reasons,
so use the new window position notify hook instead.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Right now, extension specific actions on window positioning are implemented
by wrapping the ScreenRec's PositionWindow() proc pointer: the extensions are
storing the original pointer in their private data and putting in their own one.
On each call, their proc restores the original one, calls it, and switches back
again. When multiple extensions doing so, they're forming a kind of daisy chain.
(the same is done for lots of other procs)
While that approach is looking nice and elegant on the drawing board, it's
complicated, dangerous like a chainsaw and makes debugging hard, leading to
pretty blurred API borders.
This commit introduces a simple approach for letting extension hook into the
window positioning path safely, w/o having to care much about side effects
with the call chain. Extensions now can simply register their hook proc
(and an opaque pointer) and get called back - w/o ever having to mess with
the ScreenRec's internal structures. These hooks are called before the original
vector (usually handled by DDX/screen driver directly) is called.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Right now, extension specific window destruction procedures are implemented
by wrapping the ScreenRec's DestroyWindow() proc pointer: the extensions are
storing the original pointer in their private data and putting in their own one.
On each call, their proc restores the original one, calls it, and switches back
again. When multiple extensions doing so, they're forming a kind of daisy chain.
(the same is done for lots of other procs)
While that approach is looking nice and elegant on the drawing board, it's
complicated, dangerous like a chainsaw and makes debugging hard, leading to
pretty blurred API borders.
This commit introduces a simple approach for letting extension hook into the
window destruction safely, w/o having to care much about side effects with
the call chain. Extensions now can simply register their destructor proc
(and an opaque pointer) and get called back - w/o ever having to mess with
the ScreenRec's internal structures.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Enrico Weigelt, metux IT consult