Fix: Don't create new ContractResolver on every serialization/deserialization

src/Akavache.Core/BlobCache/InMemoryBlobCache.cs

@@ -31,6 +31,7 @@ public class InMemoryBlobCache : ISecureBlobCache, IObjectBlobCache, IEnableLogg
         private Dictionary<string, CacheEntry> _cache = new Dictionary<string, CacheEntry>();
         private bool _disposed;
         private DateTimeKind? _dateTimeKind;
+        private JsonDateTimeContractResolver _jsonDateTimeContractResolver = new JsonDateTimeContractResolver(); // This will make us use ticks instead of json ticks for DateTime.
 
         /// <summary>
         /// Initializes a new instance of the <see cref="InMemoryBlobCache"/> class.
@@ -91,7 +92,16 @@ internal InMemoryBlobCache(
         public DateTimeKind? ForcedDateTimeKind
         {
             get => _dateTimeKind ?? BlobCache.ForcedDateTimeKind;
-            set => _dateTimeKind = value;
+
+            set
+            {
+                _dateTimeKind = value;
+
+                if (_jsonDateTimeContractResolver != null)
+                {
+                    _jsonDateTimeContractResolver.ForceDateTimeKindOverride = value;
+                }
+            }
         }
 
         /// <inheritdoc />
@@ -442,7 +452,8 @@ protected virtual void Dispose(bool isDisposing)
         private byte[] SerializeObject<T>(T value)
         {
             var settings = Locator.Current.GetService<JsonSerializerSettings>() ?? new JsonSerializerSettings();
-            settings.ContractResolver = new JsonDateTimeContractResolver(settings.ContractResolver, ForcedDateTimeKind); // This will make us use ticks instead of json ticks for DateTime.
+            _jsonDateTimeContractResolver.ExistingContractResolver = settings.ContractResolver;
+            settings.ContractResolver = _jsonDateTimeContractResolver;
             var serializer = JsonSerializer.Create(settings);
             using (var ms = new MemoryStream())
             {
@@ -457,7 +468,8 @@ private byte[] SerializeObject<T>(T value)
         private T DeserializeObject<T>(byte[] data)
         {
             var settings = Locator.Current.GetService<JsonSerializerSettings>() ?? new JsonSerializerSettings();
-            settings.ContractResolver = new JsonDateTimeContractResolver(settings.ContractResolver, ForcedDateTimeKind); // This will make us use ticks instead of json ticks for DateTime.
+            _jsonDateTimeContractResolver.ExistingContractResolver = settings.ContractResolver;
+            settings.ContractResolver = _jsonDateTimeContractResolver;
             var serializer = JsonSerializer.Create(settings);
             using (var reader = new BsonDataReader(new MemoryStream(data)))
             {

src/Akavache.Core/Json/JsonDateTimeContractResolver.cs

@@ -14,8 +14,13 @@ namespace Akavache
     /// </summary>
     internal class JsonDateTimeContractResolver : DefaultContractResolver
     {
-        private readonly IContractResolver _existingContractResolver;
-        private readonly DateTimeKind? _forceDateTimeKindOverride;
+        /// <summary>
+        /// Initializes a new instance of the <see cref="JsonDateTimeContractResolver"/> class.
+        /// </summary>
+        public JsonDateTimeContractResolver()
+            : this(null, null)
+        {
+        }
 
         /// <summary>
         /// Initializes a new instance of the <see cref="JsonDateTimeContractResolver"/> class.
@@ -24,14 +29,18 @@ internal class JsonDateTimeContractResolver : DefaultContractResolver
         /// <param name="forceDateTimeKindOverride">If we should override the <see cref="DateTimeKind"/>.</param>
         public JsonDateTimeContractResolver(IContractResolver contractResolver, DateTimeKind? forceDateTimeKindOverride)
         {
-            _existingContractResolver = contractResolver;
-            _forceDateTimeKindOverride = forceDateTimeKindOverride;
+            ExistingContractResolver = contractResolver;
+            ForceDateTimeKindOverride = forceDateTimeKindOverride;
         }
 
+        public IContractResolver ExistingContractResolver { get; set; }
+
+        public DateTimeKind? ForceDateTimeKindOverride { get; set; }
+
         /// <inheritdoc />
         public override JsonContract ResolveContract(Type type)
         {
-            var contract = _existingContractResolver?.ResolveContract(type);
+            var contract = ExistingContractResolver?.ResolveContract(type);
             if (contract?.Converter != null)
             {
                 return contract;
@@ -44,7 +53,7 @@ public override JsonContract ResolveContract(Type type)
 
             if (type == typeof(DateTime) || type == typeof(DateTime?))
             {
-                contract.Converter = _forceDateTimeKindOverride == DateTimeKind.Local ? JsonDateTimeTickConverter.LocalDateTimeKindDefault : JsonDateTimeTickConverter.Default;
+                contract.Converter = ForceDateTimeKindOverride == DateTimeKind.Local ? JsonDateTimeTickConverter.LocalDateTimeKindDefault : JsonDateTimeTickConverter.Default;
             }
             else if (type == typeof(DateTimeOffset) || type == typeof(DateTimeOffset?))
             {

src/Akavache.Sqlite3/SqlLiteCache/SqlRawPersistentBlobCache.cs

@@ -36,6 +36,7 @@ public class SqlRawPersistentBlobCache : IObjectBlobCache, IEnableLogger, IObjec
         private IDisposable _queueThread;
         private DateTimeKind? _dateTimeKind;
         private bool _disposed;
+        private JsonDateTimeContractResolver _jsonDateTimeContractResolver = new JsonDateTimeContractResolver(); // This will make us use ticks instead of json ticks for DateTime.
 
         /// <summary>
         /// Initializes a new instance of the <see cref="SqlRawPersistentBlobCache"/> class.
@@ -56,7 +57,16 @@ public SqlRawPersistentBlobCache(string databaseFile, IScheduler scheduler = nul
         public DateTimeKind? ForcedDateTimeKind
         {
             get => _dateTimeKind ?? BlobCache.ForcedDateTimeKind;
-            set => _dateTimeKind = value;
+
+            set
+            {
+                _dateTimeKind = value;
+
+                if (_jsonDateTimeContractResolver != null)
+                {
+                    _jsonDateTimeContractResolver.ForceDateTimeKindOverride = value;
+                }
+            }
         }
 
         /// <inheritdoc />
@@ -672,7 +682,8 @@ protected virtual IObservable<byte[]> AfterReadFromDiskFilter(byte[] data, ISche
         private byte[] SerializeObject<T>(T value)
         {
             var settings = Locator.Current.GetService<JsonSerializerSettings>() ?? new JsonSerializerSettings();
-            settings.ContractResolver = new JsonDateTimeContractResolver(settings.ContractResolver, ForcedDateTimeKind); // This will make us use ticks instead of json ticks for DateTime.
+            _jsonDateTimeContractResolver.ExistingContractResolver = settings.ContractResolver;
+            settings.ContractResolver = _jsonDateTimeContractResolver;
             var serializer = JsonSerializer.Create(settings);
             using (var ms = new MemoryStream())
             {
@@ -687,7 +698,8 @@ private byte[] SerializeObject<T>(T value)
         private IObservable<T> DeserializeObject<T>(byte[] data)
         {
             var settings = Locator.Current.GetService<JsonSerializerSettings>() ?? new JsonSerializerSettings();
-            settings.ContractResolver = new JsonDateTimeContractResolver(settings.ContractResolver, ForcedDateTimeKind); // This will make us use ticks instead of json ticks for DateTime.
+            _jsonDateTimeContractResolver.ExistingContractResolver = settings.ContractResolver;
+            settings.ContractResolver = _jsonDateTimeContractResolver;
             var serializer = JsonSerializer.Create(settings);
             using (var reader = new BsonDataReader(new MemoryStream(data)))
             {

src/Akavache.Tests/TestBases/DateTimeTestBase.cs

@@ -16,11 +16,6 @@ namespace Akavache.Tests
     /// </summary>
     public abstract class DateTimeTestBase
     {
-        /// <summary>
-        /// Time zone for when testing UTC vs local time operations. Just has to be something that doesn't match UTC.
-        /// </summary>
-        private const string TestTimeZone = "Pacific Standard Time";
-
         /// <summary>
         /// Gets the date time offsets used in theory tests.
         /// </summary>
@@ -56,7 +51,7 @@ public abstract class DateTimeTestBase
         /// <summary>
         /// Gets the date time when the tests are done to keep them consistent.
         /// </summary>
-        private static DateTime LocalTestNow { get; } = TimeZoneInfo.ConvertTimeFromUtc(TestNow.ToUniversalTime(), TimeZoneInfo.FindSystemTimeZoneById(TestTimeZone));
+        private static DateTime LocalTestNow { get; } = TimeZoneInfo.ConvertTimeFromUtc(TestNow.ToUniversalTime(), TimeZoneInfo.CreateCustomTimeZone("testTimeZone", TimeSpan.FromHours(6), "Test Time Zone", "Test Time Zone"));
 
         /// <summary>
         /// Gets the date time off set when the tests are done to keep them consistent.

src/Akavache.Tests/UtilityTests.cs

@@ -7,6 +7,7 @@
 using System.IO;
 using System.Linq;
 using System.Reactive.Subjects;
+using System.Runtime.InteropServices;
 using Xunit;
 
 namespace Akavache.Tests
@@ -36,6 +37,11 @@ public void DirectoryCreateCreatesDirectories()
         [Fact]
         public void DirectoryCreateThrowsIOExceptionForNonexistentNetworkPaths()
         {
+            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            {
+                return;
+            }
+
             var exception = Assert.Throws<IOException>(() => new DirectoryInfo(@"\\does\not\exist").CreateRecursive());
             Assert.StartsWith("The network path was not found", exception.Message);
         }
@@ -46,7 +52,21 @@ public void DirectoryCreateThrowsIOExceptionForNonexistentNetworkPaths()
         [Fact]
         public void UtilitySplitsAbsolutePaths()
         {
-            Assert.Equal(new[] { @"c:\", "foo", "bar" }, new DirectoryInfo(@"c:\foo\bar").SplitFullPath());
+            string path;
+            string expectedRoot;
+
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            {
+                path = @"c:\foo\bar";
+                expectedRoot = @"c:\";
+            }
+            else
+            {
+                path = "/foo/bar";
+                expectedRoot = "/";
+            }
+
+            Assert.Equal(new[] { expectedRoot, "foo", "bar" }, new DirectoryInfo(path).SplitFullPath());
         }
 
         /// <summary>
@@ -55,7 +75,18 @@ public void UtilitySplitsAbsolutePaths()
         [Fact]
         public void UtilityResolvesAndSplitsRelativePaths()
         {
-            var components = new DirectoryInfo(@"foo\bar").SplitFullPath().ToList();
+            string path;
+
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            {
+                path = @"foo\bar";
+            }
+            else
+            {
+                path = "foo/bar";
+            }
+
+            var components = new DirectoryInfo(path).SplitFullPath().ToList();
             Assert.True(components.Count > 2);
             Assert.Equal(new[] { "foo", "bar" }, components.Skip(components.Count - 2));
         }
@@ -66,6 +97,11 @@ public void UtilityResolvesAndSplitsRelativePaths()
         [Fact]
         public void UtilitySplitsUncPaths()
         {
+            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            {
+                return;
+            }
+
             Assert.Equal(new[] { @"\\foo\bar", "baz" }, new DirectoryInfo(@"\\foo\bar\baz").SplitFullPath());
         }