switch to flat file storage

MediaBrowser.Server.Implementations/Persistence/JsonDisplayPreferencesRepository.cs

@@ -0,0 +1,164 @@
+using MediaBrowser.Common.Configuration;
+using MediaBrowser.Controller.Persistence;
+using MediaBrowser.Model.Entities;
+using MediaBrowser.Model.Logging;
+using MediaBrowser.Model.Serialization;
+using System;
+using System.Collections.Concurrent;
+using System.IO;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace MediaBrowser.Server.Implementations.Persistence
+{
+    public class JsonDisplayPreferencesRepository : IDisplayPreferencesRepository
+    {
+        private readonly ConcurrentDictionary<string, SemaphoreSlim> _fileLocks = new ConcurrentDictionary<string, SemaphoreSlim>();
+
+        private SemaphoreSlim GetLock(string filename)
+        {
+            return _fileLocks.GetOrAdd(filename, key => new SemaphoreSlim(1, 1));
+        }
+
+        /// <summary>
+        /// Gets the name of the repository
+        /// </summary>
+        /// <value>The name.</value>
+        public string Name
+        {
+            get
+            {
+                return "Json";
+            }
+        }
+
+        /// <summary>
+        /// The _json serializer
+        /// </summary>
+        private readonly IJsonSerializer _jsonSerializer;
+
+        private readonly string _dataPath;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="JsonUserDataRepository" /> class.
+        /// </summary>
+        /// <param name="appPaths">The app paths.</param>
+        /// <param name="jsonSerializer">The json serializer.</param>
+        /// <param name="logManager">The log manager.</param>
+        /// <exception cref="System.ArgumentNullException">
+        /// jsonSerializer
+        /// or
+        /// appPaths
+        /// </exception>
+        public JsonDisplayPreferencesRepository(IApplicationPaths appPaths, IJsonSerializer jsonSerializer, ILogManager logManager)
+        {
+            if (jsonSerializer == null)
+            {
+                throw new ArgumentNullException("jsonSerializer");
+            }
+            if (appPaths == null)
+            {
+                throw new ArgumentNullException("appPaths");
+            }
+
+            _jsonSerializer = jsonSerializer;
+            _dataPath = Path.Combine(appPaths.DataPath, "display-preferences");
+        }
+
+        /// <summary>
+        /// Opens the connection to the database
+        /// </summary>
+        /// <returns>Task.</returns>
+        public Task Initialize()
+        {
+            return Task.FromResult(true);
+        }
+
+        /// <summary>
+        /// Save the display preferences associated with an item in the repo
+        /// </summary>
+        /// <param name="displayPreferences">The display preferences.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        /// <returns>Task.</returns>
+        /// <exception cref="System.ArgumentNullException">item</exception>
+        public async Task SaveDisplayPreferences(DisplayPreferences displayPreferences, CancellationToken cancellationToken)
+        {
+            if (displayPreferences == null)
+            {
+                throw new ArgumentNullException("displayPreferences");
+            }
+            if (displayPreferences.Id == Guid.Empty)
+            {
+                throw new ArgumentNullException("displayPreferences.Id");
+            }
+            if (cancellationToken == null)
+            {
+                throw new ArgumentNullException("cancellationToken");
+            }
+
+            cancellationToken.ThrowIfCancellationRequested();
+
+            if (!Directory.Exists(_dataPath))
+            {
+                Directory.CreateDirectory(_dataPath);
+            }
+
+            var path = Path.Combine(_dataPath, displayPreferences.Id + ".json");
+
+            var semaphore = GetLock(path);
+
+            await semaphore.WaitAsync(cancellationToken).ConfigureAwait(false);
+
+            try
+            {
+                _jsonSerializer.SerializeToFile(displayPreferences, path);
+            }
+            finally
+            {
+                semaphore.Release();
+            }
+        }
+
+        /// <summary>
+        /// Gets the display preferences.
+        /// </summary>
+        /// <param name="displayPreferencesId">The display preferences id.</param>
+        /// <returns>Task{DisplayPreferences}.</returns>
+        /// <exception cref="System.ArgumentNullException">item</exception>
+        public Task<DisplayPreferences> GetDisplayPreferences(Guid displayPreferencesId)
+        {
+            if (displayPreferencesId == Guid.Empty)
+            {
+                throw new ArgumentNullException("displayPreferencesId");
+            }
+
+            return Task.Run(() =>
+            {
+                var path = Path.Combine(_dataPath, displayPreferencesId + ".json");
+
+                try
+                {
+                    return _jsonSerializer.DeserializeFromFile<DisplayPreferences>(path);
+                }
+                catch (IOException)
+                {
+                    // File doesn't exist or is currently bring written to
+                    return null;
+                }
+            });
+        }
+
+        public void Dispose()
+        {
+            // Wait up to two seconds for any existing writes to finish
+            var locks = _fileLocks.Values.ToList()
+                                  .Where(i => i.CurrentCount == 1)
+                                  .Select(i => i.WaitAsync(2000));
+
+            var task = Task.WhenAll(locks);
+
+            Task.WaitAll(task);
+        }
+    }
+}