Allow Linq Query to load entities as read-only

Fixes #908 (NH-3470)

Author: hazzik

src/NHibernate.Test/Async/Linq/QueryReadOnlyTests.cs

@@ -0,0 +1,50 @@
+//------------------------------------------------------------------------------
+// <auto-generated>
+//     This code was generated by AsyncGenerator.
+//
+//     Changes to this file may cause incorrect behavior and will be lost if
+//     the code is regenerated.
+// </auto-generated>
+//------------------------------------------------------------------------------
+
+
+using System.Linq;
+using NHibernate.Linq;
+using NUnit.Framework;
+
+namespace NHibernate.Test.Linq
+{
+	using System.Threading.Tasks;
+	[TestFixture]
+	public class QueryReadOnlyTestsAsync : LinqTestCase
+	{
+		[Test]
+		public async Task CanSetReadOnlyOnLinqQueriesAsync()
+		{
+			var result = await ((from e in db.Customers
+			              where e.CompanyName == "Bon app'"
+			              select e).WithOptions(o => o.SetReadOnly(true)).ToListAsync());
+
+			Assert.That(result.All(x => session.IsReadOnly(x)), Is.True);
+		}
+
+		[Test]
+		public async Task CanSetReadOnlyOnLinqPagingQueryAsync()
+		{
+			var result = await ((from e in db.Customers
+			              select e).Skip(1).Take(1).WithOptions(o => o.SetReadOnly(true)).ToListAsync());
+
+			Assert.That(result.All(x => session.IsReadOnly(x)), Is.True);
+		}
+
+		[Test]
+		public async Task CanSetReadOnlyBeforeSkipOnLinqOrderedPageQueryAsync()
+		{
+			var result = await ((from e in db.Customers
+			              orderby e.CompanyName
+			              select e).WithOptions(o => o.SetReadOnly(true)).Skip(5).Take(5).ToListAsync());
+
+			Assert.That(result.All(x => session.IsReadOnly(x)), Is.True);
+		}
+	}
+}

src/NHibernate.Test/Linq/QueryReadOnlyTests.cs

@@ -0,0 +1,39 @@
+using System.Linq;
+using NHibernate.Linq;
+using NUnit.Framework;
+
+namespace NHibernate.Test.Linq
+{
+	[TestFixture]
+	public class QueryReadOnlyTests : LinqTestCase
+	{
+		[Test]
+		public void CanSetReadOnlyOnLinqQueries()
+		{
+			var result = (from e in db.Customers
+			              where e.CompanyName == "Bon app'"
+			              select e).WithOptions(o => o.SetReadOnly(true)).ToList();
+
+			Assert.That(result.All(x => session.IsReadOnly(x)), Is.True);
+		}
+
+		[Test]
+		public void CanSetReadOnlyOnLinqPagingQuery()
+		{
+			var result = (from e in db.Customers
+			              select e).Skip(1).Take(1).WithOptions(o => o.SetReadOnly(true)).ToList();
+
+			Assert.That(result.All(x => session.IsReadOnly(x)), Is.True);
+		}
+
+		[Test]
+		public void CanSetReadOnlyBeforeSkipOnLinqOrderedPageQuery()
+		{
+			var result = (from e in db.Customers
+			              orderby e.CompanyName
+			              select e).WithOptions(o => o.SetReadOnly(true)).Skip(5).Take(5).ToList();
+
+			Assert.That(result.All(x => session.IsReadOnly(x)), Is.True);
+		}
+	}
+}

src/NHibernate/Async/Linq/DefaultQueryProvider.cs

@@ -69,7 +69,7 @@ public Task<int> ExecuteDmlAsync<T>(QueryMode queryMode, Expression expression,
 				var query = Session.CreateQuery(nhLinqExpression);
 
 				SetParameters(query, nhLinqExpression.ParameterValuesByName);
-				ApplyOptions(query);
+				_options?.Apply(query);
 				return query.ExecuteUpdateAsync(cancellationToken);
 			}
 			catch (Exception ex)

src/NHibernate/Linq/DefaultQueryProvider.cs

@@ -175,30 +175,12 @@ protected virtual NhLinqExpression PrepareQuery(Expression expression, out IQuer
 			}
 
 			SetParameters(query, nhLinqExpression.ParameterValuesByName);
-			ApplyOptions(query);
+			_options?.Apply(query);
 			SetResultTransformerAndAdditionalCriteria(query, nhLinqExpression, nhLinqExpression.ParameterValuesByName);
 
 			return nhLinqExpression;
 		}
 
-		private void ApplyOptions(IQuery query)
-		{
-			if (_options == null) 
-				return;
-
-			if (_options.Timeout.HasValue)
-				query.SetTimeout(_options.Timeout.Value);
-			
-			if (_options.Cacheable.HasValue)
-				query.SetCacheable(_options.Cacheable.Value);
-			
-			if (_options.CacheMode.HasValue)
-				query.SetCacheMode(_options.CacheMode.Value);
-			
-			if (_options.CacheRegion != null)
-				query.SetCacheRegion(_options.CacheRegion);
-		}
-
 		protected virtual object ExecuteQuery(NhLinqExpression nhLinqExpression, IQuery query, NhLinqExpression nhQuery)
 		{
 			IList results = query.List();
@@ -279,7 +261,7 @@ public int ExecuteDml<T>(QueryMode queryMode, Expression expression)
 			var query = Session.CreateQuery(nhLinqExpression);
 
 			SetParameters(query, nhLinqExpression.ParameterValuesByName);
-			ApplyOptions(query);
+			_options?.Apply(query);
 			return query.ExecuteUpdate();
 		}
 	}

src/NHibernate/Linq/IQueryableOptions.cs

@@ -1,9 +1,13 @@
+using System;
+
 namespace NHibernate.Linq
 {
 	// Methods signatures taken from IQuery.
 	/// <summary>
 	/// Expose NH queryable options.
 	/// </summary>
+	//Since v5.1
+	[Obsolete("Please use NhQueryableOptions instead.")]
 	public interface IQueryableOptions
 	{
 		/// <summary>
@@ -29,7 +33,7 @@ public interface IQueryableOptions
 		IQueryableOptions SetCacheMode(CacheMode cacheMode);
 
 		/// <summary>
-		/// The timeout for the underlying ADO query.
+		/// Set the timeout for the underlying ADO query.
 		/// </summary>
 		/// <param name="timeout">The timeout in seconds.</param>
 		/// <returns><see langword="this"/> (for method chaining).</returns>

src/NHibernate/Linq/NhQueryableOptions.cs

@@ -1,45 +1,134 @@
 namespace NHibernate.Linq
 {
-	public class NhQueryableOptions: IQueryableOptions
+	/// <summary>
+	/// Expose NH queryable options.
+	/// </summary>
+	public class NhQueryableOptions 
+#pragma warning disable 618
+		: IQueryableOptions
+#pragma warning restore 618
 	{
-		protected internal bool? Cacheable { get; private set; }
-		protected internal CacheMode? CacheMode{ get; private set; }
-		protected internal string CacheRegion { get; private set; }
-		protected internal int? Timeout { get; private set; }
+		protected bool? Cacheable { get; private set; }
+		protected CacheMode? CacheMode { get; private set; }
+		protected string CacheRegion { get; private set; }
+		protected int? Timeout { get; private set; }
+		protected bool? ReadOnly { get; private set; }
 
-		public IQueryableOptions SetCacheable(bool cacheable)
+#pragma warning disable 618
+		/// <inheritdoc />
+		IQueryableOptions IQueryableOptions.SetCacheable(bool cacheable) => SetCacheable(cacheable);
+
+		/// <inheritdoc />
+		IQueryableOptions IQueryableOptions.SetCacheMode(CacheMode cacheMode) => SetCacheMode(cacheMode);
+
+		/// <inheritdoc />
+		IQueryableOptions IQueryableOptions.SetCacheRegion(string cacheRegion) => SetCacheRegion(cacheRegion);
+
+		/// <inheritdoc />
+		IQueryableOptions IQueryableOptions.SetTimeout(int timeout) => SetTimeout(timeout);
+#pragma warning restore 618
+
+		/// <summary>
+		/// Enable caching of this query result set.
+		/// </summary>
+		/// <param name="cacheable">Should the query results be cacheable?</param>
+		/// <returns><see langword="this"/> (for method chaining).</returns>
+		public NhQueryableOptions SetCacheable(bool cacheable)
 		{
 			Cacheable = cacheable;
 			return this;
 		}
 
-		public IQueryableOptions SetCacheMode(CacheMode cacheMode)
+		/// <summary>
+		/// Override the current session cache mode, just for this query.
+		/// </summary>
+		/// <param name="cacheMode">The cache mode to use.</param>
+		/// <returns><see langword="this"/> (for method chaining).</returns>
+		public NhQueryableOptions SetCacheMode(CacheMode cacheMode)
 		{
 			CacheMode = cacheMode;
 			return this;
 		}
 
-		public IQueryableOptions SetCacheRegion(string cacheRegion)
+		/// <summary>
+		/// Set the name of the cache region.
+		/// </summary>
+		/// <param name="cacheRegion">The name of a query cache region, or <see langword="null" />
+		/// for the default query cache</param>
+		/// <returns><see langword="this"/> (for method chaining).</returns>
+		public NhQueryableOptions SetCacheRegion(string cacheRegion)
 		{
 			CacheRegion = cacheRegion;
 			return this;
 		}
 
-		public IQueryableOptions SetTimeout(int timeout)
+		/// <summary>
+		/// Set the timeout for the underlying ADO query.
+		/// </summary>
+		/// <param name="timeout">The timeout in seconds.</param>
+		/// <returns><see langword="this"/> (for method chaining).</returns>
+		public NhQueryableOptions SetTimeout(int timeout)
 		{
 			Timeout = timeout;
 			return this;
 		}
 
-		internal NhQueryableOptions Clone()
+		/// <summary>
+		/// Set the read-only mode for entities (and proxies) loaded by this query. This setting 
+		/// overrides the default setting for the session (see <see cref="ISession.DefaultReadOnly" />).
+		/// </summary>
+		/// <remarks>
+		/// <para>
+		/// Read-only entities can be modified, but changes are not persisted. They are not 
+		/// dirty-checked and snapshots of persistent state are not maintained.
+		/// </para>
+		/// <para>
+		/// When a proxy is initialized, the loaded entity will have the same read-only setting 
+		/// as the uninitialized proxy, regardless of the session's current setting.
+		/// </para>
+		/// <para>
+		/// The read-only setting has no impact on entities or proxies returned by the criteria
+		/// that existed in the session before the criteria was executed.
+		/// </para>
+		/// </remarks>
+		/// <param name="readOnly">
+		/// If <c>true</c>, entities (and proxies) loaded by the query will be read-only.
+		/// </param>
+		/// <returns><c>this</c> (for method chaining)</returns>
+		public NhQueryableOptions SetReadOnly(bool readOnly)
+		{
+			ReadOnly = readOnly;
+			return this;
+		}
+
+		protected internal NhQueryableOptions Clone()
 		{
 			return new NhQueryableOptions
 			{
 				Cacheable = Cacheable,
 				CacheMode = CacheMode,
 				CacheRegion = CacheRegion,
-				Timeout = Timeout
+				Timeout = Timeout,
+				ReadOnly = ReadOnly
 			};
 		}
+
+		protected internal void Apply(IQuery query)
+		{
+			if (Timeout.HasValue)
+				query.SetTimeout(Timeout.Value);
+
+			if (Cacheable.HasValue)
+				query.SetCacheable(Cacheable.Value);
+
+			if (CacheMode.HasValue)
+				query.SetCacheMode(CacheMode.Value);
+
+			if (CacheRegion != null)
+				query.SetCacheRegion(CacheRegion);
+
+			if (ReadOnly.HasValue)
+				query.SetReadOnly(ReadOnly.Value);
+		}
 	}
 }