Updated row and spacer handling for Escalator (#11438)8.9.0.beta3

Updated row and spacer handling for Escalator.

Main changes:
- Spacers are only maintained and checked for rows that have DOM
representation, and not at all if there is no details generator. This
gives notable performance improvements to some particularly large Grids
- Escalator no longer tries to trim away any rows that don't fit within
the viewport just because a details row gets opened in Grid. This leads
to some increase in simultaneous DOM elements, but simplifies the logic
considerably. For example opening or closing details rows doesn't
require checking the overall content validity beyond the details row
itself anymore, but some repositioning at most. There are also no longer
any orphaned spacers without corresponding DOM rows.
- Spacers are better integrated into the overall position calculations.
- Some public methods that are no longer used by Escalator or have
changed functionality or order of operations. Any extending classes that
tap into row, spacer, or scroll position handling are likely to need
reworking after this update.
- Auto-detecting row height is delayed until Escalator is both attached
and displayed.

1 files changed, 8 insertions, 0 deletions

diff --git a/shared/src/main/java/com/vaadin/shared/ui/grid/DetailsManagerState.java b/shared/src/main/java/com/vaadin/shared/ui/grid/DetailsManagerState.java
index 1ac8987f01..cb202f96bb 100644
--- a/shared/src/main/java/com/vaadin/shared/ui/grid/DetailsManagerState.java
+++ b/shared/src/main/java/com/vaadin/shared/ui/grid/DetailsManagerState.java
@@ -22,4 +22,12 @@ package com.vaadin.shared.ui.grid;
  */
 public class DetailsManagerState extends AbstractGridExtensionState {
 
+    /**
+     * For informing the connector when details handling can be skipped
+     * altogether as it's not possible to have any details rows without a
+     * generator.
+     * 
+     * @since 8.9
+     */
+    public boolean hasDetailsGenerator = false;
 }