xf86: add helper functions to convert to from ScrnInfoPtr/ScreenPtr (v2)

These are just simple functions that we should start migrating drivers
to using.

The end goal is to remove xf86Screens and screenInfo from the ABI.

This includes a define XF86_HAS_SCRN_CONV that drivers can ifdef to provide
their own copies. I'll probably post a generic compat.h file for drivers later.

v2: add asserts.

Reviewed-by: Aaron Plattner <aplattner@nvidia.com>
Reviewed-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

2 files changed, 21 insertions, 0 deletions

diff --git a/hw/xfree86/common/xf86.h b/hw/xfree86/common/xf86.h
index e6d41d64b..ef99106e5 100644
--- a/hw/xfree86/common/xf86.h
+++ b/hw/xfree86/common/xf86.h
@@ -449,6 +449,13 @@ xf86RandRSetNewVirtualAndDimensions(ScreenPtr pScreen,
 extern _X_EXPORT Bool
 VidModeExtensionInit(ScreenPtr pScreen);
 
+/* convert ScreenPtr to ScrnInfoPtr */
+extern _X_EXPORT ScrnInfoPtr xf86ScreenToScrn(ScreenPtr pScreen);
+/* convert ScrnInfoPtr to ScreenPtr */
+extern _X_EXPORT ScreenPtr xf86ScrnToScreen(ScrnInfoPtr pScrn);
+
 #endif                          /* _NO_XF86_PROTOTYPES */
 
+#define XF86_HAS_SCRN_CONV 1 /* define for drivers to use in api compat */
+
 #endif                          /* _XF86_H */
diff --git a/hw/xfree86/common/xf86Helper.c b/hw/xfree86/common/xf86Helper.c
index 8c948cf6f..6834a0cb7 100644
--- a/hw/xfree86/common/xf86Helper.c
+++ b/hw/xfree86/common/xf86Helper.c
@@ -1834,3 +1834,17 @@ xf86MotionHistoryAllocate(InputInfoPtr pInfo)
 {
     AllocateMotionHistory(pInfo->dev);
 }
+
+ScrnInfoPtr
+xf86ScreenToScrn(ScreenPtr pScreen)
+{
+    assert(pScreen->myNum < xf86NumScreens);
+    return xf86Screens[pScreen->myNum];
+}
+
+ScreenPtr
+xf86ScrnToScreen(ScrnInfoPtr pScrn)
+{
+    assert(pScrn->scrnIndex < screenInfo.numScreens);
+    return screenInfo.screens[pScrn->scrnIndex];
+}