gbm: Export a per plane getter for stride

v2: Preserve legacy behavior when plane is 0 (Jason Ekstrand)
EINVAL when input plane is greater than total planes (Jason Ekstrand)
Don't leak the image after fromPlanar (Daniel)
Move bo->image check below plane count preventing bad index succeeding (Daniel)

v3: Fix DRIimage leak (using Jason's recommended change)
Make plane 0 return planar stride. This might break legacy behavior (Jason)

v4: Move bogus hunk for get_handle_for_plane to the right patch (Jason)
Fix error handling path to be cleaner (Jason)

v5: Add assert for dumb BOs to make sure plane == 0 (Jason)

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com> (v1)
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Acked-by: Daniel Stone <daniels@collabora.com>

src/gbm/backends/dri/gbm_dri.c

@@ -665,7 +665,40 @@ gbm_dri_bo_get_handle_for_plane(struct gbm_bo *_bo, int plane)
 static uint32_t
 gbm_dri_bo_get_stride(struct gbm_bo *_bo, int plane)
 {
-   return _bo->stride;
+   struct gbm_dri_device *dri = gbm_dri_device(_bo->gbm);
+   struct gbm_dri_bo *bo = gbm_dri_bo(_bo);
+   __DRIimage *image;
+   int stride = 0;
+
+   if (!dri->image || dri->image->base.version < 11 || !dri->image->fromPlanar) {
+      /* Preserve legacy behavior if plane is 0 */
+      if (plane == 0)
+         return _bo->stride;
+
+      errno = ENOSYS;
+      return 0;
+   }
+
+   if (plane >= get_number_planes(dri, bo->image)) {
+      errno = EINVAL;
+      return 0;
+   }
+
+   if (bo->image == NULL) {
+      assert(plane == 0);
+      return _bo->stride;
+   }
+
+   image = dri->image->fromPlanar(bo->image, plane, NULL);
+   if (image) {
+      dri->image->queryImage(image, __DRI_IMAGE_ATTRIB_STRIDE, &stride);
+      dri->image->destroyImage(image);
+   } else {
+      assert(plane == 0);
+      dri->image->queryImage(bo->image, __DRI_IMAGE_ATTRIB_STRIDE, &stride);
+   }
+
+   return (uint32_t)stride;
 }
 
 static void

src/gbm/gbm-symbols-check

@@ -14,6 +14,7 @@ gbm_bo_unmap
 gbm_bo_get_width
 gbm_bo_get_height
 gbm_bo_get_stride
+gbm_bo_get_stride_for_plane
 gbm_bo_get_format
 gbm_bo_get_device
 gbm_bo_get_handle

src/gbm/main/gbm.c

@@ -165,7 +165,20 @@ gbm_bo_get_height(struct gbm_bo *bo)
 GBM_EXPORT uint32_t
 gbm_bo_get_stride(struct gbm_bo *bo)
 {
-   return bo->gbm->bo_get_stride(bo, 0);
+   return gbm_bo_get_stride_for_plane(bo, 0);
+}
+
+/** Get the stride for the given plane
+ *
+ * \param bo The buffer object
+ * \param plane for which you want the stride
+ *
+ * \sa gbm_bo_get_stride()
+ */
+GBM_EXPORT uint32_t
+gbm_bo_get_stride_for_plane(struct gbm_bo *bo, int plane)
+{
+   return bo->gbm->bo_get_stride(bo, plane);
 }
 
 /** Get the format of the buffer object

src/gbm/main/gbm.h

@@ -303,6 +303,9 @@ gbm_bo_get_height(struct gbm_bo *bo);
 uint32_t
 gbm_bo_get_stride(struct gbm_bo *bo);
 
+uint32_t
+gbm_bo_get_stride_for_plane(struct gbm_bo *bo, int plane);
+
 uint32_t
 gbm_bo_get_format(struct gbm_bo *bo);