Add lockes to database

src/main/kotlin/mdnet/MangaDexClient.kt

@@ -70,7 +70,6 @@ class MangaDexClient(private val settingsFile: File, databaseFolder: Path, cache
         val config = HikariConfig()
         val db = databaseFolder.resolve("metadata.db")
         config.jdbcUrl = "jdbc:sqlite:$db"
-        config.maximumPoolSize = 1
         config.addDataSourceProperty("cachePrepStmts", "true")
         config.addDataSourceProperty("prepStmtCacheSize", "100")
         config.addDataSourceProperty("prepStmtCacheSqlLimit", "1000")

src/main/kotlin/mdnet/cache/ImageStorage.kt

@@ -31,7 +31,7 @@ import org.ktorm.dsl.*
 import org.slf4j.LoggerFactory
 import java.io.*
 import java.nio.file.*
-import java.sql.SQLIntegrityConstraintViolationException
+import java.sql.SQLException
 import java.time.Instant
 import java.util.UUID
 import java.util.concurrent.*
@@ -94,6 +94,7 @@ class ImageStorage(
                 val now = Instant.now()
 
                 LOGGER.info { "Updating LRU times for ${toUpdate.size} entries" }
+                synchronized(database) {
                     database.batchUpdate(DbImage) {
                         for (id in toUpdate) {
                             item {
@@ -104,6 +105,7 @@ class ImageStorage(
                             }
                         }
                     }
+                }
                 calculateSize()
             },
             1, 1, TimeUnit.MINUTES
@@ -218,7 +220,6 @@ class ImageStorage(
     private fun deleteImage(id: String) {
         LOGGER.trace { "Deleting image $id from cache" }
 
-        database.useTransaction {
         val path = getTempPath()
 
         try {
@@ -232,6 +233,7 @@ class ImageStorage(
         } catch (e: IOException) {
             // a failure means the image did not exist
         } finally {
+            synchronized(database) {
                 database.delete(DbImage) {
                     DbImage.id eq id
                 }
@@ -312,12 +314,14 @@ class ImageStorage(
             Files.createDirectories(getPath(id).parent)
 
             try {
+                synchronized(database) {
                     database.insert(DbImage) {
                         set(DbImage.id, id)
                         set(DbImage.accessed, Instant.now())
                         set(DbImage.size, metadataSize + bytes)
                     }
-            } catch (e: SQLIntegrityConstraintViolationException) {
+                }
+            } catch (e: SQLException) {
                 // someone got to us before this (TOCTOU)
                 // there are 2 situations here
                 // one is that the