From f8d6b73c0f28ea9daeaeeeb4e3ff4fd6864a4655 Mon Sep 17 00:00:00 2001
From: Lixfel <agga-games@gmx.de>
Date: Sun, 26 Sep 2021 21:46:35 +0200
Subject: [PATCH] Fix deadlock #3 :/

Signed-off-by: Lixfel <agga-games@gmx.de>
---
 src/de/steamwar/bungeecore/ErrorLogger.java   |  3 +-
 src/de/steamwar/bungeecore/sql/Statement.java | 62 +++++++++++--------
 2 files changed, 37 insertions(+), 28 deletions(-)

diff --git a/src/de/steamwar/bungeecore/ErrorLogger.java b/src/de/steamwar/bungeecore/ErrorLogger.java
index e20a704..4bfe84c 100644
--- a/src/de/steamwar/bungeecore/ErrorLogger.java
+++ b/src/de/steamwar/bungeecore/ErrorLogger.java
@@ -20,6 +20,7 @@
 package de.steamwar.bungeecore;
 
 import de.steamwar.bungeecore.sql.SWException;
+import de.steamwar.bungeecore.sql.Statement;
 
 import java.io.ByteArrayOutputStream;
 import java.io.PrintStream;
@@ -58,7 +59,7 @@ public class ErrorLogger extends Handler {
                 SWException.log("Bungee", "DDOS", ddosRate + "");
             }
             return;
-        } else if (stacktrace.contains("ErrorLogger")) {
+        } else if (!Statement.connectionStable()) {
             return;
         }
 
diff --git a/src/de/steamwar/bungeecore/sql/Statement.java b/src/de/steamwar/bungeecore/sql/Statement.java
index eac7650..c37538b 100644
--- a/src/de/steamwar/bungeecore/sql/Statement.java
+++ b/src/de/steamwar/bungeecore/sql/Statement.java
@@ -40,39 +40,48 @@ public class Statement {
         Statement.user = user;
         Statement.password = password;
         try {
-            con = DriverManager.getConnection(url + "?autoreconnect=true", user, password);
+            con = DriverManager.getConnection(url + "?autoreconnect=true&useServerPrepStmts=true", user, password);
         } catch (SQLException e) {
             ProxyServer.getInstance().stop();
             throw new SecurityException("Could not start SQL-Connection", e);
         }
     }
 
-    private static void reset(SQLException e) {
-        BungeeCore.get().getLogger().log(Level.WARNING, "SQL Exception thrown", e);
+    private static void reset() {
         close();
         connect(url, user, password);
         try {
             for (Statement statement : statements) {
                 statement.init();
             }
-        } catch (SQLException ex) {
-            throw new SecurityException("Could not reprepare SQL Statements", ex);
+        } catch (SQLException e) {
+            throw new SecurityException("Could not reprepare SQL statements", e);
         }
     }
 
     public static void close() {
-        for (Statement statement : statements) {
+        synchronized (statements) {
+            for (Statement statement : statements) {
+                try {
+                    statement.st.close();
+                } catch (SQLException e) {
+                    BungeeCore.get().getLogger().log(Level.INFO, "Could not close statement", e);
+                }
+            }
+
             try {
-                statement.st.close();
+                con.close();
             } catch (SQLException e) {
-                BungeeCore.get().getLogger().log(Level.INFO, "Could not close statement", e);
+                BungeeCore.get().getLogger().log(Level.INFO, "Could not close SQL connection", e);
             }
         }
+    }
 
+    public static boolean connectionStable() {
         try {
-            con.close();
+            return !con.isClosed();
         } catch (SQLException e) {
-            BungeeCore.log("Could not close SQL-Connection", e);
+            return false;
         }
     }
 
@@ -85,39 +94,38 @@ public class Statement {
         try {
             init();
         } catch (SQLException e) {
-            reset(e);
+            throw new SecurityException("Could not init SQL statement", e);
         }
     }
 
-    private synchronized void init() throws SQLException {
+    private void init() throws SQLException {
         st = con.prepareStatement(sql);
     }
 
     <T> T select(ResultSetUser<T> user, Object... objects) {
-        return prepare(() -> {
-            ResultSet rs = st.executeQuery();
-            T result = user.use(rs);
-            rs.close();
-            return result;
-        }, objects);
+        synchronized (statements) {
+            return prepare(() -> {
+                ResultSet rs = st.executeQuery();
+                T result = user.use(rs);
+                rs.close();
+                return result;
+            }, objects);
+        }
     }
 
     void update(Object... objects) {
-        prepare(st::executeUpdate, objects);
+        synchronized (statements) {
+            prepare(st::executeUpdate, objects);
+        }
     }
 
-    private synchronized <T> T prepare(SQLRunnable<T> runnable, Object... objects) {
+    private <T> T prepare(SQLRunnable<T> runnable, Object... objects) {
         try {
             setObjects(objects);
             return runnable.run();
         } catch (SQLException e) {
-            reset(e);
-            try {
-                setObjects(objects);
-                return runnable.run();
-            } catch (SQLException ex) {
-                throw new SecurityException("Could not execute SQL statement", ex);
-            }
+            reset();
+            throw new SecurityException("Could not execute SQL statement", e);
         }
     }