Version 4.13.0

2026-04-06 06:55:04 +00:00 · 2019-07-21 00:17:16 +02:00 · 2019-07-21 00:17:16 +02:00 · 8244ddb5c3
commit 8244ddb5c3
parent 8b08d721d4
13 changed files with 625 additions and 739 deletions
--- a/FileDbCache/Shared/FileDbCache.cs
+++ b/FileDbCache/Shared/FileDbCache.cs
@ -0,0 +1,141 @@
+// XAML Map Control - https://github.com/ClemensFischer/XAML-Map-Control
+// © 2019 Clemens Fischer
+// Licensed under the Microsoft Public License (Ms-PL)
+
+using FileDbNs;
+using System;
+using System.Diagnostics;
+using System.IO;
+
+namespace MapControl.Caching
+{
+    /// <summary>
+    /// Image cache implementation based on FileDb, a free and simple No-SQL database by EzTools Software.
+    /// See http://www.eztools-software.com/tools/filedb/.
+    /// </summary>
+    public sealed partial class FileDbCache : IDisposable
+    {
+        private const string keyField = "Key";
+        private const string valueField = "Value";
+        private const string expiresField = "Expires";
+
+        private readonly FileDb fileDb = new FileDb() { AutoFlush = true };
+        private readonly string dbPath;
+
+        public void Dispose()
+        {
+            fileDb.Dispose();
+        }
+
+        public void Clean()
+        {
+            if (fileDb.IsOpen)
+            {
+                int deleted = fileDb.DeleteRecords(new FilterExpression(expiresField, DateTime.UtcNow, ComparisonOperatorEnum.LessThan));
+
+                if (deleted > 0)
+                {
+                    Debug.WriteLine("FileDbCache: Deleted {0} expired items", deleted);
+                    fileDb.Clean();
+                }
+            }
+        }
+
+        private void Open()
+        {
+            if (!fileDb.IsOpen)
+            {
+                try
+                {
+                    fileDb.Open(dbPath);
+                    Debug.WriteLine("FileDbCache: Opened database " + dbPath);
+
+                    Clean();
+                }
+                catch
+                {
+                    CreateDatabase();
+                }
+            }
+        }
+
+        private void Close()
+        {
+            if (fileDb.IsOpen)
+            {
+                fileDb.Close();
+            }
+        }
+
+        private void CreateDatabase()
+        {
+            Close();
+
+            if (File.Exists(dbPath))
+            {
+                File.Delete(dbPath);
+            }
+            else
+            {
+                Directory.CreateDirectory(Path.GetDirectoryName(dbPath));
+            }
+
+            fileDb.Create(dbPath, new Field[]
+            {
+                new Field(keyField, DataTypeEnum.String) { IsPrimaryKey = true },
+                new Field(valueField, DataTypeEnum.Byte) { IsArray = true },
+                new Field(expiresField, DataTypeEnum.DateTime)
+            });
+
+            Debug.WriteLine("FileDbCache: Created database " + dbPath);
+        }
+
+        private Record GetRecordByKey(string key)
+        {
+            Record record = null;
+
+            if (fileDb.IsOpen)
+            {
+                try
+                {
+                    record = fileDb.GetRecordByKey(key, new string[] { valueField, expiresField }, false);
+                }
+                catch (Exception ex)
+                {
+                    Debug.WriteLine("FileDbCache.GetRecordByKey(\"{0}\"): {1}", key, ex.Message);
+                }
+            }
+
+            return record;
+        }
+
+        private void AddOrUpdateRecord(string key, byte[] value, DateTime expiration)
+        {
+            if (fileDb.IsOpen)
+            {
+                var fieldValues = new FieldValues(3);
+                fieldValues.Add(valueField, value);
+                fieldValues.Add(expiresField, expiration);
+
+                try
+                {
+                    if (fileDb.GetRecordByKey(key, new string[0], false) != null)
+                    {
+                        fileDb.UpdateRecordByKey(key, fieldValues);
+                    }
+                    else
+                    {
+                        fieldValues.Add(keyField, key);
+                        fileDb.AddRecord(fieldValues);
+                    }
+
+                    //Debug.WriteLine("FileDbCache: Writing \"{0}\", Expires {1}", key, imageCacheItem.Expiration.ToLocalTime());
+                }
+                catch (Exception ex)
+                {
+                    Debug.WriteLine("FileDbCache.AddOrUpdateRecord(\"{0}\"): {1}", key, ex.Message); return;
+                }
+            }
+        }
+    }
+}