From 0cd01e33c38b0f8d69da0f4f5060ebe9e815ddbd Mon Sep 17 00:00:00 2001
From: Konstantin Knizhnik <knizhnik@garret.ru>
Date: Tue, 21 Mar 2023 23:30:02 +0200
Subject: [PATCH] Add LayerMap::contains method

---
 pageserver/src/tenant/layer_map.rs                | 15 +++++++++++++++
 .../tenant/layer_map/historic_layer_coverage.rs   |  8 +-------
 2 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/pageserver/src/tenant/layer_map.rs b/pageserver/src/tenant/layer_map.rs
index 8d06ccd565..449560f390 100644
--- a/pageserver/src/tenant/layer_map.rs
+++ b/pageserver/src/tenant/layer_map.rs
@@ -122,6 +122,13 @@ impl<L> BatchedUpdates<'_, L>
 where
     L: ?Sized + Layer,
 {
+    ///
+    /// Check if layer map contains layers with specified key and LSN range
+    ///
+    pub fn contains(&self, layer: Arc<L>) -> bool {
+        self.layer_map.contains(layer)
+    }
+
     ///
     /// Insert an on-disk layer.
     ///
@@ -268,6 +275,14 @@ where
         BatchedUpdates { layer_map: self }
     }
 
+    ///
+    /// Check if layer map contains layers with specified key and LSN range
+    ///
+    pub fn contains(&self, layer: Arc<L>) -> bool {
+        self.historic
+            .contains(historic_layer_coverage::LayerKey::from(&*layer))
+    }
+
     ///
     /// Insert an on-disk layer
     ///
diff --git a/pageserver/src/tenant/layer_map/historic_layer_coverage.rs b/pageserver/src/tenant/layer_map/historic_layer_coverage.rs
index f4d758e784..b63c361314 100644
--- a/pageserver/src/tenant/layer_map/historic_layer_coverage.rs
+++ b/pageserver/src/tenant/layer_map/historic_layer_coverage.rs
@@ -418,12 +418,6 @@ impl<Value: Clone> BufferedHistoricLayerCoverage<Value> {
     }
 
     pub fn insert(&mut self, layer_key: LayerKey, value: Value) {
-        // layer duplicates are not allowed
-        assert!(!self.layers.contains_key(&layer_key));
-        self.buffer.insert(layer_key, Some(value));
-    }
-
-    pub fn replace_existed(&mut self, layer_key: LayerKey, value: Value) {
         self.buffer.insert(layer_key, Some(value));
     }
 
@@ -478,7 +472,7 @@ impl<Value: Clone> BufferedHistoricLayerCoverage<Value> {
             }
             None => Replacement::NotFound,
             Some(_existing) => {
-                self.replace_existed(layer_key.to_owned(), new);
+                self.insert(layer_key.to_owned(), new);
                 Replacement::Replaced { in_buffered }
             }
         }