From 7ff4c9ffcd146e0f7dc65c0e50a8a90ae4843edd Mon Sep 17 00:00:00 2001
From: Michael Meeks <michael.meeks@collabora.com>
Date: Thu, 16 Jun 2022 14:42:40 +0100
Subject: [PATCH] delta: don't clear keyframes from the cache that have deltas
 coming.

These will get newer wids later of course.

Signed-off-by: Michael Meeks <michael.meeks@collabora.com>
Change-Id: I906f47255854eb065d41e629508867ffa6e9f953
---
 wsd/DocumentBroker.cpp |  4 +++-
 wsd/TileCache.cpp      | 18 +++++++++++++++---
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/wsd/DocumentBroker.cpp b/wsd/DocumentBroker.cpp
index aa704a387..5433d0c15 100644
--- a/wsd/DocumentBroker.cpp
+++ b/wsd/DocumentBroker.cpp
@@ -2745,7 +2745,8 @@ void DocumentBroker::handleTileCombinedRequest(TileCombined& tileCombined, bool
 
     assert(!tileCombined.hasDuplicates());
 
-    LOG_TRC("TileCombined request for " << tileCombined.serialize());
+    LOG_TRC("TileCombined request for " << tileCombined.serialize() << " from " <<
+            (forceKeyframe ? "client" : "wsd"));
     if (!hasTileCache())
     {
         LOG_WRN("Combined tile request without a loaded document?");
@@ -2767,6 +2768,7 @@ void DocumentBroker::handleTileCombinedRequest(TileCombined& tileCombined, bool
             // case; so forget what we last sent.
             LOG_TRC("forcing a keyframe for tilecombined tile");
             session->resetTileSeq(tile);
+            tile.setOldWireId(0); // forceKeyframe in the request
         }
 
         Tile cachedTile = _tileCache->lookupTile(tile);
diff --git a/wsd/TileCache.cpp b/wsd/TileCache.cpp
index 09ead6a1e..a9fc3bdb6 100644
--- a/wsd/TileCache.cpp
+++ b/wsd/TileCache.cpp
@@ -588,6 +588,7 @@ void TileCache::ensureCacheSize()
     if (wids.back()._wid - wids.front()._wid > 256 * 256 * 256)
     {
         maxToRemove = wids.back()._wid;
+        LOG_TRC("Rare wid wrap-around detected, clear tile cache");
     }
     else
     {
@@ -608,9 +609,20 @@ void TileCache::ensureCacheSize()
     {
         if (it->first.getWireId() <= maxToRemove)
         {
-            LOG_TRC("cleaned out tile: " << it->first.serialize());
-            _cacheSize -= itemCacheSize(it->second);
-            it = _cache.erase(it);
+            auto rit = _tilesBeingRendered.find(it->first);
+            if (rit != _tilesBeingRendered.end())
+            {
+                // avoid getting a delta instead of a keyframe at the bottom.
+                LOG_TRC("skip cleaning tile we are waiting on: " << it->first.serialize() <<
+                        " which has " << rit->second->getSubscribers().size() << " waiting");
+                ++it;
+            }
+            else
+            {
+                LOG_TRC("cleaned out tile: " << it->first.serialize());
+                _cacheSize -= itemCacheSize(it->second);
+                it = _cache.erase(it);
+            }
         }
         else
         {