File 0007-base-Add-an-EplImplFuncs-function-for-EGL_BUFFER_AGE.patch of Package libnvidia-egl-wayland2

From 94f578e48cbcde2468385b7187b71d22b2bb9ba2 Mon Sep 17 00:00:00 2001
From: Kyle Brenneman <kbrenneman@nvidia.com>
Date: Tue, 14 Oct 2025 16:42:08 -0600
Subject: [PATCH 07/18] base: Add an EplImplFuncs function for EGL_BUFFER_AGE.

Add a new function, EplImplFuncs::QueryBufferAge, which is used to check
the value of EGL_BUFFER_AGE for a surface.
---
 src/base/platform-base.c | 23 +++++++++++++++++++----
 src/base/platform-impl.h | 12 ++++++++++++
 2 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/src/base/platform-base.c b/src/base/platform-base.c
index 94aa4b7..f746fe3 100644
--- a/src/base/platform-base.c
+++ b/src/base/platform-base.c
@@ -1329,10 +1329,25 @@ static EGLBoolean HookQuerySurface(EGLDisplay edpy, EGLSurface esurf, EGLint att
                 goto done;
             }
 
-            // Note: This is where we'll call into the platform-specific code
-            // once we add a query function to EplImplFuncs. Until then,
-            // returning zero is valid (if not very useful).
-            *value = 0;
+            if (pdpy->platform->impl->QueryBufferAge != NULL)
+            {
+                EGLint age = pdpy->platform->impl->QueryBufferAge(pdpy, psurf);
+                if (age < 0)
+                {
+                    goto done;
+                }
+
+                *value = age;
+            }
+            else
+            {
+                /*
+                 * If the platform code doesn't implement this, then just return
+                 * zero. That's always valid, and means that the application can't
+                 * make any assumptions about the buffer's contents.
+                 */
+                *value = 0;
+            }
 
             psurf->bufferAgeCalled = EGL_TRUE;
             ret = EGL_TRUE;
diff --git a/src/base/platform-impl.h b/src/base/platform-impl.h
index e3a865d..d767f3b 100644
--- a/src/base/platform-impl.h
+++ b/src/base/platform-impl.h
@@ -309,6 +309,18 @@ typedef struct _EplImplFuncs
      * \return EGL_TRUE on success, or EGL_FALSE on failure.
      */
     EGLBoolean (* SwapInterval) (EplDisplay *pdpy, EplSurface *psurf, EGLint interval);
+
+    /**
+     * Returns the value of EGL_BUFFER_AGE_KHR.
+     *
+     * This function is optional. If it's NULL, then the base library will just
+     * return zero.
+     *
+     * \param pdpy The current display.
+     * \param psurf The current draw surface. This will never be NULL.
+     * \return The buffer age, or -1 on error.
+     */
+    EGLint (* QueryBufferAge) (EplDisplay *pdpy, EplSurface *psurf);
 } EplImplFuncs;
 
 #ifdef __cplusplus
-- 
2.51.0