From 1a55b2dcccc2d70791419365f9b6d740c1f87165 Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Sun, 14 Mar 2021 19:24:25 +0000
Subject: [PATCH] allow map_piece_update_op to return None

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---
 src/pcrender.rs | 7 ++++---
 src/updates.rs  | 3 +--
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/pcrender.rs b/src/pcrender.rs
index d25167fe..02e96ed0 100644
--- a/src/pcrender.rs
+++ b/src/pcrender.rs
@@ -39,9 +39,9 @@ impl PieceRenderInstructions {
   pub fn map_piece_update_op(&self, ioccults: &IOccults,
                              gpc: &GPiece, ipc: &IPiece,
                              op: PieceUpdateOp<(),()>
-  ) -> PieceUpdateOp<PreparedPieceState, ZLevel>
+  ) -> Option<PieceUpdateOp<PreparedPieceState, ZLevel>>
   {
-    op.try_map(
+    let op = op.try_map(
       |()|{
         let ns = self.prep_piecestate(ioccults, gpc, ipc)?;
         <Result<_,InternalError>>::Ok(ns)
@@ -49,7 +49,8 @@ impl PieceRenderInstructions {
       |()|{
         Ok(gpc.zlevel.clone())
       }
-    )?
+    )?;
+    Some(op)
   }
   
   #[throws(IE)]
diff --git a/src/updates.rs b/src/updates.rs
index b6eb9013..e73235b2 100644
--- a/src/updates.rs
+++ b/src/updates.rs
@@ -507,8 +507,7 @@ impl<'r> PrepareUpdatesBuffer<'r> {
     max_z.update_max(&gpc.zlevel.z);
 
     let op = pri.map_piece_update_op(ioccults, gpc, ipc, op)?;
-
-    Some(PreparedPieceUpdate {
+    op.map(|op| PreparedPieceUpdate {
       piece: pri.vpid,
       op,
     })
-- 
2.30.2