dri3: Add GLX_EXT_buffer_age support

v2: Indent according to Mesa style, reuse sbc instead of making a new
    swap_count field, and actually get a usable back before returning the
    age of the back (fixing updated piglit tests).  Changes by anholt.

Signed-off-by: Adel Gadllah <[email protected]>
Reviewed-by: Robert Bragg <[email protected]> (v1)
Reviewed-by: Adel Gadllah <[email protected]> (v2)
Reviewed-by: Eric Anholt <[email protected]>

1 files changed, 30 insertions, 3 deletions

diff --git a/src/glx/glx_pbuffer.c b/src/glx/glx_pbuffer.c
index 978730cecb3..0cd05545786 100644
--- a/src/glx/glx_pbuffer.c
+++ b/src/glx/glx_pbuffer.c
@@ -285,6 +285,10 @@ GetDrawableAttribute(Display * dpy, GLXDrawable drawable,
    unsigned int num_attributes;
    GLboolean use_glx_1_3;
 
+#if defined(GLX_DIRECT_RENDERING) && !defined(GLX_USE_APPLEGL)
+   __GLXDRIdrawable *pdraw;
+#endif
+
    if (dpy == NULL)
       return 0;
 
@@ -311,6 +315,32 @@ GetDrawableAttribute(Display * dpy, GLXDrawable drawable,
    if (!opcode)
       return 0;
 
+#if defined(GLX_DIRECT_RENDERING) && !defined(GLX_USE_APPLEGL)
+   pdraw = GetGLXDRIDrawable(dpy, drawable);
+
+   if (attribute == GLX_BACK_BUFFER_AGE_EXT) {
+      struct glx_screen *psc = pdraw->psc;
+      struct glx_context *gc = __glXGetCurrentContext();
+
+      /* The GLX_EXT_buffer_age spec says:
+       *
+       *   "If querying GLX_BACK_BUFFER_AGE_EXT and <draw> is not bound to
+       *   the calling thread's current context a GLXBadDrawable error is
+       *   generated."
+       */
+      if (gc == NULL || gc->currentDpy != dpy ||
+         (gc->currentDrawable != drawable && gc->currentReadable != drawable)) {
+         __glXSendError(dpy, GLXBadDrawable, drawable, X_GLXGetDrawableAttributes, false);
+         return 0;
+      }
+
+      if (psc->driScreen->getBufferAge != NULL)
+         *value = psc->driScreen->getBufferAge(pdraw);
+
+      return 0;
+   }
+#endif
+
    LockDisplay(dpy);
 
    if (use_glx_1_3) {
@@ -350,9 +380,6 @@ GetDrawableAttribute(Display * dpy, GLXDrawable drawable,
          _XEatData(dpy, length);
       }
       else {
-#if defined(GLX_DIRECT_RENDERING) && !defined(GLX_USE_APPLEGL)
-         __GLXDRIdrawable *pdraw = GetGLXDRIDrawable(dpy, drawable);
-#endif
          _XRead(dpy, (char *) data, length * sizeof(CARD32));
 
          /* Search the set of returned attributes for the attribute requested by