D23618: Use nullptr everywhere

zzag created this revision.
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Herald added a project: KWin.
Herald added a subscriber: kwin.
zzag requested review of this revision.

REVISION SUMMARY
  Because KWin is a very old project, we use three kinds of null literals:
  0, NULL, and nullptr. Since C++11, it's recommended to use nullptr keyword.
  
  This change converts all usages of 0 and NULL literal to nullptr. Even
  though it breaks git history, we need to do it in order to have consistent
  code as well to ease code reviews (it's very tempting for some people to
  add unrelated changes to their patches, e.g. converting NULL to nullptr).

TEST PLAN
  Compiles.

REPOSITORY
  R108 KWin

BRANCH
  use-nullptr-everywhere

REVISION DETAIL
  https://phabricator.kde.org/D23618

AFFECTED FILES
  abstract_client.cpp
  activation.cpp
  activities.cpp
  client.cpp
  client.h
  client_machine.cpp
  client_machine.h
  colorcorrection/manager.cpp
  composite.cpp
  composite.h
  cursor.cpp
  deleted.cpp
  effects.cpp
  effects/backgroundcontrast/contrastshader.cpp
  effects/blur/blur_config.h
  effects/coverswitch/coverswitch.cpp
  effects/coverswitch/coverswitch.h
  effects/coverswitch/coverswitch_config.h
  effects/cube/cube.cpp
  effects/cube/cube_config.h
  effects/cubeslide/cubeslide.cpp
  effects/cubeslide/cubeslide_config.h
  effects/desktopgrid/desktopgrid.cpp
  effects/desktopgrid/desktopgrid.h
  effects/desktopgrid/desktopgrid_config.h
  effects/flipswitch/flipswitch.cpp
  effects/flipswitch/flipswitch_config.h
  effects/highlightwindow/highlightwindow.cpp
  effects/highlightwindow/highlightwindow.h
  effects/invert/invert.cpp
  effects/invert/invert_config.h
  effects/lookingglass/lookingglass.cpp
  effects/lookingglass/lookingglass_config.h
  effects/magiclamp/magiclamp.cpp
  effects/magiclamp/magiclamp_config.h
  effects/magnifier/magnifier.cpp
  effects/magnifier/magnifier_config.h
  effects/mouseclick/mouseclick.cpp
  effects/mouseclick/mouseclick_config.h
  effects/mousemark/mousemark.cpp
  effects/mousemark/mousemark_config.h
  effects/presentwindows/presentwindows.cpp
  effects/presentwindows/presentwindows.h
  effects/presentwindows/presentwindows_config.h
  effects/resize/resize.cpp
  effects/resize/resize_config.h
  effects/screenedge/screenedgeeffect.cpp
  effects/screenshot/screenshot.cpp
  effects/showfps/showfps.cpp
  effects/showfps/showfps_config.h
  effects/slideback/slideback.cpp
  effects/startupfeedback/startupfeedback.cpp
  effects/thumbnailaside/thumbnailaside.cpp
  effects/thumbnailaside/thumbnailaside_config.h
  effects/touchpoints/touchpoints.cpp
  effects/trackmouse/trackmouse.cpp
  effects/trackmouse/trackmouse_config.h
  effects/windowgeometry/windowgeometry.cpp
  effects/windowgeometry/windowgeometry_config.h
  effects/wobblywindows/wobblywindows_config.h
  effects/zoom/zoom.cpp
  effects/zoom/zoom_config.h
  events.cpp
  focuschain.cpp
  geometry.cpp
  geometrytip.cpp
  group.cpp
  input.cpp
  kcmkwin/kwincompositing/compositing.h
  kcmkwin/kwincompositing/main.cpp
  kcmkwin/kwindecoration/declarative-plugin/buttonsmodel.h
  kcmkwin/kwindecoration/declarative-plugin/previewitem.cpp
  kcmkwin/kwindecoration/declarative-plugin/previewsettings.h
  kcmkwin/kwinoptions/mouse.cpp
  kcmkwin/kwinscreenedges/monitor.h
  kcmkwin/kwintabbox/thumbnailitem.cpp
  layers.cpp
  libkwineffects/kwinglplatform.cpp
  libkwineffects/kwinglutils.cpp
  manage.cpp
  netinfo.cpp
  options.h
  placement.cpp
  platformsupport/scenes/opengl/backend.cpp
  platformsupport/scenes/opengl/linux_dmabuf.cpp
  plugins/idletime/poller.h
  plugins/kglobalaccel/kglobalaccel_plugin.h
  plugins/platforms/wayland/wayland_backend.cpp
  plugins/platforms/x11/standalone/glxbackend.cpp
  plugins/platforms/x11/standalone/overlaywindow_x11.cpp
  plugins/platforms/x11/standalone/windowselector.cpp
  plugins/qpa/sharingplatformcontext.cpp
  plugins/scenes/opengl/lanczosfilter.cpp
  plugins/scenes/opengl/lanczosfilter.h
  plugins/scenes/opengl/scene_opengl.cpp
  plugins/scenes/opengl/scene_opengl.h
  plugins/scenes/qpainter/scene_qpainter.cpp
  plugins/scenes/xrender/scene_xrender.cpp
  scene.cpp
  screenedge.cpp
  screens.cpp
  scripting/dbuscall.h
  scripting/screenedgeitem.h
  scripting/workspace_wrapper.cpp
  shadow.cpp
  sm.cpp
  tabbox/tabbox.cpp
  tabgroup.cpp
  tabgroup.h
  tests/pointerconstraintstest.cpp
  thumbnailitem.cpp
  thumbnailitem.h
  toplevel.cpp
  unmanaged.cpp
  useractions.cpp
  useractions.h
  utils.cpp
  virtualdesktops.cpp
  workspace.cpp
  workspace.h
  xcbutils.cpp
  xcbutils.h
  xkb.cpp
  xwl/drag_x.cpp
  xwl/transfer.cpp

To: zzag, #kwin
Cc: kwin, LeGast00n, The-Feren-OS-Dev, sbergeron, jraleigh, fbampaloukas, GB_2, mkulinski, ragreen, jackyalcine, Pitel, iodelay, crozbo, bwowk, ZrenBot, ngraham, alexeymin, himcesjf, lesliezhai, ali-mohamed, hardening, romangg, jensreuterberg, abetts, sebas, apol, mart