Replaced local file caching by persistent ObjectCache based on FileDb.

Removed IsCached and ImageType properties from TileLayer.

Caches/FileDbCache/FileDbCache.cs

@@ -0,0 +1,444 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.IO;
+using System.Runtime.Caching;
+using System.Runtime.Serialization.Formatters.Binary;
+using FileDbNs;
+
+namespace Caching
+{
+    /// <summary>
+    /// ObjectCache implementation based on EzTools FileDb - http://www.eztools-software.com/tools/filedb/.
+    /// </summary>
+    public class FileDbCache : ObjectCache, IDisposable
+    {
+        private const string keyField = "Key";
+        private const string valueField = "Value";
+        private const string expiresField = "Expires";
+
+        private readonly BinaryFormatter formatter = new BinaryFormatter();
+        private readonly FileDb fileDb = new FileDb();
+        private readonly string name;
+        private readonly string path;
+
+        public FileDbCache(string name, string path)
+        {
+            if (string.IsNullOrEmpty(path))
+            {
+                throw new ArgumentException("The parameter path must not be null or empty.");
+            }
+
+            if (string.IsNullOrEmpty(Path.GetExtension(path)))
+            {
+                path += ".fdb";
+            }
+
+            this.name = name;
+            this.path = path;
+
+            try
+            {
+                fileDb.Open(path, false);
+            }
+            catch
+            {
+                CreateDatebase();
+            }
+
+            Trace.TraceInformation("FileDbCache created with {0} cached items", fileDb.NumRecords);
+        }
+
+        public bool AutoFlush
+        {
+            get { return fileDb.AutoFlush; }
+            set { fileDb.AutoFlush = value; }
+        }
+
+        public int AutoCleanThreshold
+        {
+            get { return fileDb.AutoCleanThreshold; }
+            set { fileDb.AutoCleanThreshold = value; }
+        }
+
+        public override string Name
+        {
+            get { return name; }
+        }
+
+        public override DefaultCacheCapabilities DefaultCacheCapabilities
+        {
+            get { return DefaultCacheCapabilities.InMemoryProvider | DefaultCacheCapabilities.AbsoluteExpirations | DefaultCacheCapabilities.SlidingExpirations; }
+        }
+
+        public override object this[string key]
+        {
+            get { return Get(key); }
+            set { Set(key, value, null); }
+        }
+
+        protected override IEnumerator<KeyValuePair<string, object>> GetEnumerator()
+        {
+            throw new NotSupportedException("FileDbCache does not support the ability to enumerate items.");
+        }
+
+        public override CacheEntryChangeMonitor CreateCacheEntryChangeMonitor(IEnumerable<string> keys, string regionName = null)
+        {
+            throw new NotSupportedException("FileDbCache does not support the ability to create change monitors.");
+        }
+
+        public override long GetCount(string regionName = null)
+        {
+            if (regionName != null)
+            {
+                throw new NotSupportedException("The parameter regionName must be null.");
+            }
+
+            long count = 0;
+
+            try
+            {
+                count = fileDb.NumRecords;
+            }
+            catch
+            {
+                if (CheckReindex())
+                {
+                    try
+                    {
+                        count = fileDb.NumRecords;
+                    }
+                    catch
+                    {
+                        CreateDatebase();
+                    }
+                }
+            }
+
+            return count;
+        }
+
+        public override bool Contains(string key, string regionName = null)
+        {
+            if (regionName != null)
+            {
+                throw new NotSupportedException("The parameter regionName must be null.");
+            }
+
+            if (key == null)
+            {
+                throw new ArgumentNullException("The parameter key must not be null.");
+            }
+
+            bool contains = false;
+
+            try
+            {
+                contains = fileDb.GetRecordByKey(key, new string[0], false) != null;
+            }
+            catch
+            {
+                if (CheckReindex())
+                {
+                    try
+                    {
+                        contains = fileDb.GetRecordByKey(key, new string[0], false) != null;
+                    }
+                    catch
+                    {
+                        CreateDatebase();
+                    }
+                }
+            }
+
+            return contains;
+        }
+
+        public override object Get(string key, string regionName = null)
+        {
+            if (regionName != null)
+            {
+                throw new NotSupportedException("The parameter regionName must be null.");
+            }
+
+            if (key == null)
+            {
+                throw new ArgumentNullException("The parameter key must not be null.");
+            }
+
+            object value = null;
+            Record record = null;
+
+            try
+            {
+                record = fileDb.GetRecordByKey(key, new string[] { valueField }, false);
+            }
+            catch
+            {
+                if (CheckReindex())
+                {
+                    try
+                    {
+                        record = fileDb.GetRecordByKey(key, new string[] { valueField }, false);
+                    }
+                    catch
+                    {
+                        CreateDatebase();
+                    }
+                }
+            }
+
+            if (record != null)
+            {
+                try
+                {
+                    using (MemoryStream stream = new MemoryStream((byte[])record[0]))
+                    {
+                        value = formatter.Deserialize(stream);
+                    }
+                }
+                catch (Exception exc)
+                {
+                    Trace.TraceWarning("FileDbCache.Get({0}): {1}", key, exc.Message);
+
+                    try
+                    {
+                        fileDb.DeleteRecordByKey(key);
+                    }
+                    catch
+                    {
+                    }
+                }
+            }
+
+            return value;
+        }
+
+        public override CacheItem GetCacheItem(string key, string regionName = null)
+        {
+            var value = Get(key, regionName);
+            return value != null ? new CacheItem(key, value) : null;
+        }
+
+        public override IDictionary<string, object> GetValues(IEnumerable<string> keys, string regionName = null)
+        {
+            if (regionName != null)
+            {
+                throw new NotSupportedException("The parameter regionName must be null.");
+            }
+
+            var values = new Dictionary<string, object>();
+
+            foreach (string key in keys)
+            {
+                values[key] = Get(key);
+            }
+
+            return values;
+        }
+
+        public override void Set(string key, object value, CacheItemPolicy policy, string regionName = null)
+        {
+            if (regionName != null)
+            {
+                throw new NotSupportedException("The parameter regionName must be null.");
+            }
+
+            if (value == null)
+            {
+                throw new ArgumentNullException("The parameter value must not be null.");
+            }
+
+            if (key == null)
+            {
+                throw new ArgumentNullException("The parameter key must not be null.");
+            }
+
+            byte[] valueBuffer = null;
+
+            try
+            {
+                using (MemoryStream stream = new MemoryStream())
+                {
+                    formatter.Serialize(stream, value);
+                    valueBuffer = stream.ToArray();
+                }
+            }
+            catch (Exception exc)
+            {
+                Trace.TraceWarning("FileDbCache.Set({0}): {1}", key, exc.Message);
+            }
+
+            if (valueBuffer != null)
+            {
+                DateTime expires = DateTime.MaxValue;
+
+                if (policy.AbsoluteExpiration != InfiniteAbsoluteExpiration)
+                {
+                    expires = policy.AbsoluteExpiration.DateTime;
+                }
+                else if (policy.SlidingExpiration != NoSlidingExpiration)
+                {
+                    expires = DateTime.UtcNow + policy.SlidingExpiration;
+                }
+
+                try
+                {
+                    AddOrUpdateRecord(key, valueBuffer, expires);
+                }
+                catch
+                {
+                    if (CheckReindex())
+                    {
+                        try
+                        {
+                            AddOrUpdateRecord(key, valueBuffer, expires);
+                        }
+                        catch
+                        {
+                            CreateDatebase();
+                            AddOrUpdateRecord(key, valueBuffer, expires);
+                        }
+                    }
+                }
+            }
+        }
+
+        public override void Set(CacheItem item, CacheItemPolicy policy)
+        {
+            Set(item.Key, item.Value, policy, item.RegionName);
+        }
+
+        public override void Set(string key, object value, DateTimeOffset absoluteExpiration, string regionName = null)
+        {
+            Set(key, value, new CacheItemPolicy { AbsoluteExpiration = absoluteExpiration }, regionName);
+        }
+
+        public override object AddOrGetExisting(string key, object value, CacheItemPolicy policy, string regionName = null)
+        {
+            var oldValue = Get(key, regionName);
+            Set(key, value, policy);
+            return oldValue;
+        }
+
+        public override CacheItem AddOrGetExisting(CacheItem item, CacheItemPolicy policy)
+        {
+            var oldItem = GetCacheItem(item.Key, item.RegionName);
+            Set(item, policy);
+            return oldItem;
+        }
+
+        public override object AddOrGetExisting(string key, object value, DateTimeOffset absoluteExpiration, string regionName = null)
+        {
+            return AddOrGetExisting(key, value, new CacheItemPolicy { AbsoluteExpiration = absoluteExpiration }, regionName);
+        }
+
+        public override object Remove(string key, string regionName = null)
+        {
+            var oldValue = Get(key, regionName);
+
+            if (oldValue != null)
+            {
+                try
+                {
+                    fileDb.DeleteRecordByKey(key);
+                }
+                catch
+                {
+                }
+            }
+
+            return oldValue;
+        }
+
+        public void Flush()
+        {
+            try
+            {
+                fileDb.Flush();
+            }
+            catch
+            {
+                CheckReindex();
+            }
+        }
+
+        public void Clean()
+        {
+            try
+            {
+                fileDb.Clean();
+            }
+            catch
+            {
+                CheckReindex();
+            }
+        }
+
+        public void Dispose()
+        {
+            try
+            {
+                fileDb.DeleteRecords(new FilterExpression(expiresField, DateTime.UtcNow, EqualityEnum.LessThanOrEqual));
+                Trace.TraceInformation("FileDbCache has deleted {0} expired items", fileDb.NumDeleted);
+                fileDb.Clean();
+                fileDb.Close();
+            }
+            catch
+            {
+                if (CheckReindex())
+                {
+                    fileDb.Close();
+                }
+            }
+        }
+
+        private bool CheckReindex()
+        {
+            if (fileDb.IsOpen)
+            {
+                Trace.TraceWarning("FileDbCache is reindexing database");
+                fileDb.Reindex();
+                return true;
+            }
+
+            return false;
+        }
+
+        private void CreateDatebase()
+        {
+            if (File.Exists(path))
+            {
+                File.Delete(path);
+            }
+            else
+            {
+                Directory.CreateDirectory(Path.GetDirectoryName(path));
+            }
+
+            fileDb.Create(path, new Field[]
+                {
+                    new Field(keyField, DataTypeEnum.String) { IsPrimaryKey = true },
+                    new Field(valueField, DataTypeEnum.Byte) { IsArray = true },
+                    new Field(expiresField, DataTypeEnum.DateTime)
+                });
+        }
+
+        private void AddOrUpdateRecord(string key, object value, DateTime expires)
+        {
+            var fieldValues = new FieldValues(3); // capacity
+            fieldValues.Add(valueField, value);
+            fieldValues.Add(expiresField, expires);
+
+            if (fileDb.GetRecordByKey(key, new string[0], false) == null)
+            {
+                fieldValues.Add(keyField, key);
+                fileDb.AddRecord(fieldValues);
+            }
+            else
+            {
+                fileDb.UpdateRecordByKey(key, fieldValues);
+            }
+        }
+    }
+}