From 5a69235013bcbae1aba8cb988e8984e7a341f114 Mon Sep 17 00:00:00 2001 From: "Enrico Weigelt, metux IT consult" Date: Tue, 24 Sep 2024 17:58:33 +0200 Subject: [PATCH] (!1714) dix: add per-screen window position notify hook 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 --- dix/dix_priv.h | 12 ++++++++++++ dix/screen_hooks.c | 14 +++++++++++++ dix/window.c | 20 +++++++++---------- include/dix_screen_hooks.h | 36 ++++++++++++++++++++++++++++++++++ include/scrnintstr.h | 4 ++++ include/xorg-server.h.meson.in | 1 + mi/miwindow.c | 5 +++-- 7 files changed, 80 insertions(+), 12 deletions(-) diff --git a/dix/dix_priv.h b/dix/dix_priv.h index dcbe6ac888..018d3a7f3d 100644 --- a/dix/dix_priv.h +++ b/dix/dix_priv.h @@ -268,4 +268,16 @@ void MakePredeclaredAtoms(void); */ int dixScreenRaiseWindowDestroy(WindowPtr pWin); +/* + * @brief call screen's window position notification hooks + * @see dixScreenHookWindowPosition + * @param pWin the window to notify on + * + * Call the pluggable window position hooks that extensions might have registered on + * the screen, and finally call ScreenRec's PositionWindow proc. + * + * Should only be called by DIX itself. + */ +void dixScreenRaiseWindowPosition(WindowPtr pWin, uint32_t x, uint32_t y); + #endif /* _XSERVER_DIX_PRIV_H */ diff --git a/dix/screen_hooks.c b/dix/screen_hooks.c index df95c06c4f..bdebbd725e 100644 --- a/dix/screen_hooks.c +++ b/dix/screen_hooks.c @@ -41,6 +41,7 @@ } DECLARE_HOOK_LIST(WindowDestroy, _notify_window_destroy) +DECLARE_HOOK_LIST(WindowPosition, _notify_window_position) int dixScreenRaiseWindowDestroy(WindowPtr pWin) { @@ -55,3 +56,16 @@ int dixScreenRaiseWindowDestroy(WindowPtr pWin) } return (pScreen->DestroyWindow ? (*pScreen->DestroyWindow) (pWin) : Success); } + +void dixScreenRaiseWindowPosition(WindowPtr pWin, uint32_t x, uint32_t y) +{ + ScreenPtr pScreen = pWin->drawable.pScreen; + + ARRAY_FOR_EACH(pScreen->_notify_window_position, walk) { + if (walk.ptr->func) + walk.ptr->func(pScreen, pWin, walk.ptr->arg, x, y); + } + + if (pScreen->PositionWindow) + (*pScreen->PositionWindow) (pWin, x, y); +} diff --git a/dix/window.c b/dix/window.c index 901fcfc775..db413b8abc 100644 --- a/dix/window.c +++ b/dix/window.c @@ -670,7 +670,8 @@ InitRootWindow(WindowPtr pWin) if (!(*pScreen->CreateWindow) (pWin)) return; /* XXX */ - (*pScreen->PositionWindow) (pWin, 0, 0); + + dixScreenRaiseWindowPosition(pWin, 0, 0); pWin->cursorIsNone = FALSE; pWin->optional->cursor = RefCursor(rootCursor); @@ -928,7 +929,7 @@ CreateWindow(Window wid, WindowPtr pParent, int x, int y, unsigned w, return NullWindow; } /* We SHOULD check for an error value here XXX */ - (*pScreen->PositionWindow) (pWin, pWin->drawable.x, pWin->drawable.y); + dixScreenRaiseWindowPosition(pWin, pWin->drawable.x, pWin->drawable.y); if (!(vmask & CWEventMask)) RecalculateDeliverableEvents(pWin); @@ -1848,12 +1849,9 @@ GravityTranslate(int x, int y, int oldx, int oldy, void ResizeChildrenWinSize(WindowPtr pWin, int dx, int dy, int dw, int dh) { - ScreenPtr pScreen; WindowPtr pSib, pChild; Bool resized = (dw || dh); - pScreen = pWin->drawable.pScreen; - for (pSib = pWin->firstChild; pSib; pSib = pSib->nextSib) { if (resized && (pSib->winGravity > NorthWestGravity)) { int cwsx, cwsy; @@ -1878,7 +1876,8 @@ ResizeChildrenWinSize(WindowPtr pWin, int dx, int dy, int dw, int dh) pSib->drawable.y = pWin->drawable.y + pSib->origin.y; SetWinSize(pSib); SetBorderSize(pSib); - (*pScreen->PositionWindow) (pSib, pSib->drawable.x, pSib->drawable.y); + + dixScreenRaiseWindowPosition(pSib, pSib->drawable.x, pSib->drawable.y); if ((pChild = pSib->firstChild)) { while (1) { @@ -1888,9 +1887,9 @@ ResizeChildrenWinSize(WindowPtr pWin, int dx, int dy, int dw, int dh) pChild->origin.y; SetWinSize(pChild); SetBorderSize(pChild); - (*pScreen->PositionWindow) (pChild, - pChild->drawable.x, - pChild->drawable.y); + dixScreenRaiseWindowPosition(pChild, + pChild->drawable.x, + pChild->drawable.y); if (pChild->firstChild) { pChild = pChild->firstChild; continue; @@ -2584,7 +2583,8 @@ ReparentWindow(WindowPtr pWin, WindowPtr pParent, if (pScreen->ReparentWindow) (*pScreen->ReparentWindow) (pWin, pPriorParent); - (*pScreen->PositionWindow) (pWin, pWin->drawable.x, pWin->drawable.y); + + dixScreenRaiseWindowPosition(pWin, pWin->drawable.x, pWin->drawable.y); ResizeChildrenWinSize(pWin, 0, 0, 0, 0); CheckWindowOptionalNeed(pWin); diff --git a/include/dix_screen_hooks.h b/include/dix_screen_hooks.h index a00cd8d8a4..f896c21e68 100644 --- a/include/dix_screen_hooks.h +++ b/include/dix_screen_hooks.h @@ -72,4 +72,40 @@ _X_EXPORT void dixScreenUnhookWindowDestroy(ScreenPtr pScreen, XorgWindowDestroyProcPtr func, void *arg); +/* prototype of a window move notification handler */ +typedef void (*XorgWindowPositionProcPtr)(ScreenPtr pScreen, + WindowPtr pWindow, + void *arg, + int32_t x, + int32_t y); + +/** + * @brief register a position notify hook on the given screen + * + * @param pScreen pointer to the screen to register the notify hook into + * @param func pointer to the window hook function + * @param arg opaque pointer passed to the hook + * + * When registration fails, the server aborts. + * + **/ +_X_EXPORT void dixScreenHookWindowPosition(ScreenPtr pScreen, + XorgWindowPositionProcPtr func, + void *arg); + +/** + * @brief unregister a window position notify hook on the given screen + * + * @param pScreen pointer to the screen to unregister the hook from + * @param func pointer to the hook function + * @param arg opaque pointer passed to the destructor + * + * @see dixScreenHookWindowPosition + * + * Unregister a window position notify hook registered via @ref dixScreenHookWindowPosition + **/ +_X_EXPORT void dixScreenUnhookWindowPosition(ScreenPtr pScreen, + XorgWindowPositionProcPtr func, + void *arg); + #endif /* DIX_SCREEN_HOOKS_H */ diff --git a/include/scrnintstr.h b/include/scrnintstr.h index ef76eaa4c0..ae4059f936 100644 --- a/include/scrnintstr.h +++ b/include/scrnintstr.h @@ -561,6 +561,10 @@ typedef struct _Screen { should NOT be touched outside of DIX core */ _SCREEN_HOOK_TYPE(_notify_window_destroy, XorgWindowDestroyProcPtr, 8); + /* additional window position notify hooks (replaces wrapping PositionWindow) + should NOT be touched outside of DIX core */ + _SCREEN_HOOK_TYPE(_notify_window_position, XorgWindowPositionProcPtr, 4); + /* Pixmap procedures */ CreatePixmapProcPtr CreatePixmap; diff --git a/include/xorg-server.h.meson.in b/include/xorg-server.h.meson.in index 392d8ede57..58bada9232 100644 --- a/include/xorg-server.h.meson.in +++ b/include/xorg-server.h.meson.in @@ -216,5 +216,6 @@ /* announce server API features */ #define XORG_API_DIX_SCREEN_HOOK_WINDOW_DESTROY 1 +#define XORG_API_DIX_SCREEN_HOOK_WINDOW_POSITION 1 #endif /* _XORG_SERVER_H_ */ diff --git a/mi/miwindow.c b/mi/miwindow.c index a4b97a7b83..4a71d53874 100644 --- a/mi/miwindow.c +++ b/mi/miwindow.c @@ -50,6 +50,7 @@ SOFTWARE. #include #include "dix/cursor_priv.h" +#include "dix/dix_priv.h" #include "dix/input_priv.h" #include "mi/mi_priv.h" @@ -276,7 +277,7 @@ miMoveWindow(WindowPtr pWin, int x, int y, WindowPtr pNextSib, VTKind kind) SetWinSize(pWin); SetBorderSize(pWin); - (*pScreen->PositionWindow) (pWin, x, y); + dixScreenRaiseWindowPosition(pWin, x, y); windowToValidate = MoveWindowInStack(pWin, pNextSib); @@ -446,7 +447,7 @@ miResizeWindow(WindowPtr pWin, int x, int y, unsigned int w, unsigned int h, ResizeChildrenWinSize(pWin, x - oldx, y - oldy, dw, dh); /* let the hardware adjust background and border pixmaps, if any */ - (*pScreen->PositionWindow) (pWin, x, y); + dixScreenRaiseWindowPosition(pWin, x, y); pFirstChange = MoveWindowInStack(pWin, pSib);