Version 4.13.0

SQLiteCache/Shared/SQLiteCache.cs

@@ -0,0 +1,75 @@
+// XAML Map Control - https://github.com/ClemensFischer/XAML-Map-Control
+// © 2019 Clemens Fischer
+// Licensed under the Microsoft Public License (Ms-PL)
+
+using System;
+using System.Diagnostics;
+#if WINDOWS_UWP
+using SQLiteCommand = Microsoft.Data.Sqlite.SqliteCommand;
+using SQLiteConnection = Microsoft.Data.Sqlite.SqliteConnection;
+#else
+using System.Data.SQLite;
+#endif
+
+namespace MapControl.Caching
+{
+    /// <summary>
+    /// Image cache implementation based on SqLite.
+    /// </summary>
+    public sealed partial class SQLiteCache : IDisposable
+    {
+        private readonly SQLiteConnection connection;
+
+        private static SQLiteConnection Open(string path)
+        {
+            var connection = new SQLiteConnection("Data Source=" + path);
+            connection.Open();
+
+            using (var command = new SQLiteCommand("create table if not exists items (key text primary key, expiration integer, buffer blob)", connection))
+            {
+                command.ExecuteNonQuery();
+            }
+
+            Debug.WriteLine("SQLiteCache: Opened database " + path);
+
+            return connection;
+        }
+
+        public void Dispose()
+        {
+            connection.Dispose();
+        }
+
+        public void Clean()
+        {
+            using (var command = new SQLiteCommand("delete from items where expiration < @exp", connection))
+            {
+                command.Parameters.AddWithValue("@exp", DateTime.UtcNow.Ticks);
+                command.ExecuteNonQuery();
+            }
+        }
+
+        private SQLiteCommand GetItemCommand(string key)
+        {
+            var command = new SQLiteCommand("select expiration, buffer from items where key=@key", connection);
+            command.Parameters.AddWithValue("@key", key);
+            return command;
+        }
+
+        private SQLiteCommand SetItemCommand(string key, DateTime expiration, byte[] buffer)
+        {
+            var command = new SQLiteCommand("insert or replace into items (key, expiration, buffer) values (@key, @exp, @buf)", connection);
+            command.Parameters.AddWithValue("@key", key);
+            command.Parameters.AddWithValue("@exp", expiration.Ticks);
+            command.Parameters.AddWithValue("@buf", buffer);
+            return command;
+        }
+
+        private SQLiteCommand RemoveItemCommand(string key)
+        {
+            var command = new SQLiteCommand("delete from items where key = @key", connection);
+            command.Parameters.AddWithValue("@key", key);
+            return command;
+        }
+    }
+}