Introduce uninitialize for sessions (#1940)

* Introduce uninitialize for sessions

* Add FlagValueChangeHandler#onClearValue

worldguard-bukkit/src/main/java/com/sk89q/worldguard/bukkit/BukkitWorldGuardPlatform.java

@@ -146,6 +146,7 @@ public void load() {
 
     @Override
     public void unload() {
+        sessionManager.shutdown();
         configuration.unload();
         regionContainer.shutdown();
     }

worldguard-bukkit/src/main/java/com/sk89q/worldguard/bukkit/listener/PlayerMoveListener.java

@@ -148,6 +148,8 @@ public void onPlayerQuit(PlayerQuitEvent event) {
         if (loc != null) {
             player.teleport(BukkitAdapter.adapt(loc));
         }
+
+        session.uninitialize(localPlayer);
     }
 
     private class EntityMountListener implements Listener {

worldguard-bukkit/src/main/java/com/sk89q/worldguard/bukkit/session/BukkitSessionManager.java

@@ -100,4 +100,11 @@ public boolean isUsingTimings() {
     public void setUsingTimings(boolean useTimings) {
         this.useTimings = useTimings;
     }
+
+    public void shutdown() {
+        for (Player player : Bukkit.getServer().getOnlinePlayers()) {
+            LocalPlayer localPlayer = WorldGuardPlugin.inst().wrapPlayer(player);
+            get(localPlayer).uninitialize(localPlayer);
+        }
+    }
 }

worldguard-core/src/main/java/com/sk89q/worldguard/session/Session.java

@@ -120,6 +120,21 @@ public void initialize(LocalPlayer player) {
         }
     }
 
+    /**
+     * Uninitialize the session.
+     *
+     * @param player The player
+     */
+    public void uninitialize(LocalPlayer player) {
+        RegionQuery query = WorldGuard.getInstance().getPlatform().getRegionContainer().createQuery();
+        Location location = player.getLocation();
+        ApplicableRegionSet set = query.getApplicableRegions(location);
+
+        for (Handler handler : handlers.values()) {
+            handler.uninitialize(player, location, set);
+        }
+    }
+
     /**
      * Tick the session.
      *

worldguard-core/src/main/java/com/sk89q/worldguard/session/handler/FlagValueChangeHandler.java

@@ -45,6 +45,12 @@ public final void initialize(LocalPlayer player, Location current, ApplicableReg
         onInitialValue(player, set, lastValue);
     }
 
+    @Override
+    public final void uninitialize(LocalPlayer player, Location current, ApplicableRegionSet set) {
+        onClearValue(player, set);
+        lastValue = null;
+    }
+
     @Override
     public boolean onCrossBoundary(LocalPlayer player, Location from, Location to, ApplicableRegionSet toSet, Set<ProtectedRegion> entered, Set<ProtectedRegion> exited, MoveType moveType) {
         if (entered.isEmpty() && exited.isEmpty()
@@ -74,4 +80,8 @@ public boolean onCrossBoundary(LocalPlayer player, Location from, Location to, A
 
     protected abstract boolean onAbsentValue(LocalPlayer player, Location from, Location to, ApplicableRegionSet toSet, T lastValue, MoveType moveType);
 
+    protected void onClearValue(LocalPlayer player, ApplicableRegionSet set) {
+        Location current = player.getLocation();
+        onAbsentValue(player, current, current, set, lastValue, MoveType.OTHER_NON_CANCELLABLE);
+    }
 }

worldguard-core/src/main/java/com/sk89q/worldguard/session/handler/Handler.java

@@ -74,6 +74,16 @@ public Session getSession() {
     public void initialize(LocalPlayer player, Location current, ApplicableRegionSet set) {
     }
 
+    /**
+     * Called when the session should clear its caches.
+     *
+     * @param player The player
+     * @param current The player's current location
+     * @param set The regions for the current location
+     */
+    public void uninitialize(LocalPlayer player, Location current, ApplicableRegionSet set) {
+    }
+
     /**
      * Called when {@link Session#testMoveTo(LocalPlayer, Location, MoveType)} is called.
      *