D6323: Remove roundtrip to XServer from Workspace::xStackingOrderIntroduce a method Workspace::markXStackingOrderAsDirty

[Martin Flöser]

graesslin created this revision.
Restricted Application added a project: KWin.
Restricted Application added subscribers: kwin, plasma-devel.

REVISION SUMMARY
  This method replaces the calls x_stacking_dirty = true in the code base
  allowing for further refactoring of that functionality.
  
  Remove roundtrip to XServer from Workspace::xStackingOrder
  
  The method xStackingOrder is only used during a Compositor paint pass.
  If the stacking order had changed, the method updated the stacking order
  from X by performing a sync XQueryTree. With other words we had a round
  trip to the X server directly in the paint pass.
  
  This change rearchitectures this area by making better use of xcb. When
  we notice that the stacking order changed and an XQueryTree is needed,
  we directly send out the request. When xStackingOrder is finally called,
  which normally happens a few milliseconds later, the reply is retreived.
  In the worst case it still blocks, but in most cases the roundtrip is
  gone.
  
  If the stacking order changed again before accessing xStackingOrder the
  running request is cancelled and a new request is issued. So whenever we
  get into xStackingOrder it will have the current state.
  
  The updating of the xStackingOrder is moved into a dedicated method and
  xStackingOrder invokes it through a const_cast instead of operating on
  mutable variables.

TEST PLAN
  Normal system usage, no issues

REPOSITORY
  R108 KWin

BRANCH
  xstacking-no-roundtrip

REVISION DETAIL
  https://phabricator.kde.org/D6323

AFFECTED FILES
  composite.cpp
  events.cpp
  layers.cpp
  workspace.cpp
  workspace.h

To: graesslin, #kwin, #plasma
Cc: plasma-devel, kwin, ZrenBot, spstarr, progwolff, lesliezhai, ali-mohamed, hardening, jensreuterberg, abetts, sebas, apol, mart, lukas
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.kde.org/pipermail/plasma-devel/attachments/20170621/84635fa5/attachment-0001.html>