Add locate support for SQLite (#2392)

* It supported since Release 3.7.15 On 2012-12-12)
* Simulate locate(text, value, startIndex)

Author: bahusoid

src/NHibernate.Test/Async/Hql/HQLFunctions.cs

@@ -310,7 +310,6 @@ public async Task SubStringAsync()
 		[Test]
 		public async Task LocateAsync()
 		{
-			AssumeFunctionSupported("locate");
 			using (ISession s = OpenSession())
 			{
 				Animal a1 = new Animal("abcdef", 20);

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

@@ -13,8 +13,8 @@
 using System.Text.RegularExpressions;
 using NHibernate.DomainModel;
 using NHibernate.DomainModel.Northwind.Entities;
-using NHibernate.Linq;
 using NUnit.Framework;
+using NHibernate.Linq;
 
 namespace NHibernate.Test.Linq
 {
@@ -195,9 +195,6 @@ where e.FirstName.StartsWith("An")
 		[Test]
 		public async Task CharIndexFunctionAsync()
 		{
-			if (!TestDialect.SupportsLocate)
-				Assert.Ignore("Locate function not supported.");
-
 			var raw = await ((from e in db.Employees select e.FirstName).ToListAsync());
 			var expected = raw.Select(x => x.ToLower()).Where(x => x.IndexOf('a') == 0).ToList();
 
@@ -214,9 +211,6 @@ where lowerName.IndexOf('a') == 0
 		[Test]
 		public async Task CharIndexOffsetNegativeFunctionAsync()
 		{
-			if (!TestDialect.SupportsLocate)
-				Assert.Ignore("Locate function not supported.");
-
 			var raw = await ((from e in db.Employees select e.FirstName).ToListAsync());
 			var expected = raw.Select(x => x.ToLower()).Where(x => x.IndexOf('a', 2) == -1).ToList();
 
@@ -233,9 +227,6 @@ where lowerName.IndexOf('a', 2) == -1
 		[Test]
 		public async Task IndexOfFunctionExpressionAsync()
 		{
-			if (!TestDialect.SupportsLocate)
-				Assert.Ignore("Locate function not supported.");
-
 			var raw = await ((from e in db.Employees select e.FirstName).ToListAsync());
 			var expected = raw.Select(x => x.ToLower()).Where(x => x.IndexOf("an") == 0).ToList();
 
@@ -252,9 +243,6 @@ where lowerName.IndexOf("an") == 0
 		[Test]
 		public async Task IndexOfFunctionProjectionAsync()
 		{
-			if (!TestDialect.SupportsLocate)
-				Assert.Ignore("Locate function not supported.");
-
 			var raw = await ((from e in db.Employees select e.FirstName).ToListAsync());
 			var expected = raw.Select(x => x.ToLower()).Where(x => x.Contains("a")).Select(x => x.IndexOf("a", 1)).ToList();
 
@@ -271,9 +259,6 @@ where lowerName.Contains("a")
 		[Test]
 		public async Task TwoFunctionExpressionAsync()
 		{
-			if (!TestDialect.SupportsLocate)
-				Assert.Ignore("Locate function not supported.");
-
 			var query = from e in db.Employees
 						where e.FirstName.IndexOf("A") == e.BirthDate.Value.Month 
 						select e.FirstName;

src/NHibernate.Test/Hql/HQLFunctions.cs

@@ -299,7 +299,6 @@ public void SubString()
 		[Test]
 		public void Locate()
 		{
-			AssumeFunctionSupported("locate");
 			using (ISession s = OpenSession())
 			{
 				Animal a1 = new Animal("abcdef", 20);

src/NHibernate.Test/Linq/FunctionTests.cs

@@ -3,7 +3,6 @@
 using System.Text.RegularExpressions;
 using NHibernate.DomainModel;
 using NHibernate.DomainModel.Northwind.Entities;
-using NHibernate.Linq;
 using NUnit.Framework;
 
 namespace NHibernate.Test.Linq
@@ -184,9 +183,6 @@ where e.FirstName.StartsWith("An")
 		[Test]
 		public void CharIndexFunction()
 		{
-			if (!TestDialect.SupportsLocate)
-				Assert.Ignore("Locate function not supported.");
-
 			var raw = (from e in db.Employees select e.FirstName).ToList();
 			var expected = raw.Select(x => x.ToLower()).Where(x => x.IndexOf('a') == 0).ToList();
 
@@ -203,9 +199,6 @@ where lowerName.IndexOf('a') == 0
 		[Test]
 		public void CharIndexOffsetNegativeFunction()
 		{
-			if (!TestDialect.SupportsLocate)
-				Assert.Ignore("Locate function not supported.");
-
 			var raw = (from e in db.Employees select e.FirstName).ToList();
 			var expected = raw.Select(x => x.ToLower()).Where(x => x.IndexOf('a', 2) == -1).ToList();
 
@@ -222,9 +215,6 @@ where lowerName.IndexOf('a', 2) == -1
 		[Test]
 		public void IndexOfFunctionExpression()
 		{
-			if (!TestDialect.SupportsLocate)
-				Assert.Ignore("Locate function not supported.");
-
 			var raw = (from e in db.Employees select e.FirstName).ToList();
 			var expected = raw.Select(x => x.ToLower()).Where(x => x.IndexOf("an") == 0).ToList();
 
@@ -241,9 +231,6 @@ where lowerName.IndexOf("an") == 0
 		[Test]
 		public void IndexOfFunctionProjection()
 		{
-			if (!TestDialect.SupportsLocate)
-				Assert.Ignore("Locate function not supported.");
-
 			var raw = (from e in db.Employees select e.FirstName).ToList();
 			var expected = raw.Select(x => x.ToLower()).Where(x => x.Contains("a")).Select(x => x.IndexOf("a", 1)).ToList();
 
@@ -260,9 +247,6 @@ where lowerName.Contains("a")
 		[Test]
 		public void TwoFunctionExpression()
 		{
-			if (!TestDialect.SupportsLocate)
-				Assert.Ignore("Locate function not supported.");
-
 			var query = from e in db.Employees
 						where e.FirstName.IndexOf("A") == e.BirthDate.Value.Month 
 						select e.FirstName;

src/NHibernate.Test/TestCase.cs

@@ -440,7 +440,6 @@ protected DateTime RoundForDialect(DateTime value)
 		private static readonly Dictionary<string, HashSet<System.Type>> DialectsNotSupportingStandardFunction =
 			new Dictionary<string, HashSet<System.Type>>
 			{
-				{"locate", new HashSet<System.Type> {typeof (SQLiteDialect)}},
 				{"bit_length", new HashSet<System.Type> {typeof (SQLiteDialect)}},
 				{"extract", new HashSet<System.Type> {typeof (SQLiteDialect)}},
 				{

src/NHibernate.Test/TestDialect.cs

@@ -44,7 +44,6 @@ public bool NativeGeneratorSupportsBulkInsertion
 
 		public virtual bool SupportsOperatorAll => true;
 		public virtual bool SupportsOperatorSome => true;
-		public virtual bool SupportsLocate => true;
 
 		public virtual bool SupportsFullJoin => true;
 

src/NHibernate.Test/TestDialects/SQLiteTestDialect.cs

@@ -22,11 +22,6 @@ public override bool SupportsOperatorSome
 			get { return false; }
 		}
 
-		public override bool SupportsLocate
-		{
-			get { return false; }
-		}
-
 		public override bool SupportsFullJoin
 		{
 			get { return false; }

src/NHibernate/Dialect/SQLiteDialect.cs

@@ -1,10 +1,14 @@
 using System;
+using System.Collections;
 using System.Collections.Generic;
 using System.Data;
 using System.Data.Common;
+using System.Linq;
 using System.Text;
 using NHibernate.Dialect.Function;
+using NHibernate.Engine;
 using NHibernate.SqlCommand;
+using NHibernate.Type;
 using NHibernate.Util;
 
 namespace NHibernate.Dialect
@@ -109,6 +113,7 @@ protected virtual void RegisterFunctions()
 			RegisterFunction("trim", new AnsiTrimEmulationFunction());
 			RegisterFunction("replace", new StandardSafeSQLFunction("replace", NHibernateUtil.String, 3));
 			RegisterFunction("chr", new StandardSQLFunction("char", NHibernateUtil.Character));
+			RegisterFunction("locate", new LocateFunction());
 
 			RegisterFunction("mod", new ModulusFunctionTemplate(false));
 
@@ -513,5 +518,72 @@ protected override bool CastingIsRequired(string sqlType)
 				return true;
 			}
 		}
+
+		[Serializable]
+		private class LocateFunction : ISQLFunction, ISQLFunctionExtended
+		{
+			// Since v5.3
+			[Obsolete("Use GetReturnType method instead.")]
+			public IType ReturnType(IType columnType, IMapping mapping)
+			{
+				return NHibernateUtil.Int32;
+			}
+
+			/// <inheritdoc />
+			public IType GetReturnType(IEnumerable<IType> argumentTypes, IMapping mapping, bool throwOnError)
+			{
+#pragma warning disable 618
+				return ReturnType(argumentTypes.FirstOrDefault(), mapping);
+#pragma warning restore 618
+			}
+
+			/// <inheritdoc />
+			public IType GetEffectiveReturnType(IEnumerable<IType> argumentTypes, IMapping mapping, bool throwOnError)
+			{
+				return GetReturnType(argumentTypes, mapping, throwOnError);
+			}
+
+			/// <inheritdoc />
+			public string Name => "instr";
+
+			public bool HasArguments => true;
+
+			public bool HasParenthesesIfNoArguments => true;
+
+			public SqlString Render(IList args, ISessionFactoryImplementor factory)
+			{
+				if (args.Count != 2 && args.Count != 3)
+				{
+					throw new QueryException("'locate' function takes 2 or 3 arguments. Provided count: " + args.Count);
+				}
+
+				if (args.Count == 2)
+				{
+					return new SqlString("instr(", args[1], ", ", args[0], ")");
+				}
+
+				var text = args[1];
+				var value = args[0];
+				var startIndex = args[2];
+				//ifnull(
+				//	nullif(
+				//		instr(substr(text, startIndex), value)
+				//		, 0)
+				//	+ startIndex -1
+				//, 0)
+				return
+					new SqlString(
+						"ifnull(nullif(instr(substr(",
+						text,
+						", ",
+						startIndex,
+						"), ",
+						value,
+						"), 0) + ",
+						startIndex,
+						" -1, 0)"
+					);
+			}
+		}
 	}
 }