NH-3901, NH-3846 - Correct IndexOfGenerator index offsets

src/NHibernate.Test/Hql/SimpleFunctionsTest.cs

@@ -131,7 +131,7 @@ public void PositionSubstring()
 			args.Add("'a'");
 			args.Add("va2");
 			args.Add("2");
-			Assert.AreEqual("(position('a' in substring(va2, 2))+2-1)", psf.Render(args, factoryImpl).ToString());
+			Assert.AreEqual("(case position('a' in substring(va2, 2)) when 0 then 0 else (position('a' in substring(va2, 2))+2-1) end)", psf.Render(args, factoryImpl).ToString());
 		}
 
 		[Test]

src/NHibernate.Test/Linq/FunctionTests.cs

@@ -131,10 +131,35 @@ 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();
+
 			var query = from e in db.Employees
-						where e.FirstName.IndexOf('A') == 1
-						select e.FirstName;
+						let lowerName = e.FirstName.ToLower()
+						where lowerName.IndexOf('a') == 0
+						select lowerName;
+			var result = query.ToList();
 
+			Assert.That(result, Is.EqualTo(expected), "Expected {0} but was {1}", string.Join("|", expected), string.Join("|", result));
+			ObjectDumper.Write(query);
+		}
+
+		[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();
+
+			var query = from e in db.Employees
+						let lowerName = e.FirstName.ToLower()
+						where lowerName.IndexOf('a', 2) == -1
+						select lowerName;
+			var result = query.ToList();
+
+			Assert.That(result, Is.EqualTo(expected), "Expected {0} but was {1}", string.Join("|", expected), string.Join("|", result));
 			ObjectDumper.Write(query);
 		}
 
@@ -144,10 +169,16 @@ 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();
+
 			var query = from e in db.Employees
-						where e.FirstName.IndexOf("An") == 1
-						select e.FirstName;
+						let lowerName = e.FirstName.ToLower()
+						where lowerName.IndexOf("an") == 0
+						select lowerName;
+			var result = query.ToList();
 
+			Assert.That(result, Is.EqualTo(expected), "Expected {0} but was {1}", string.Join("|", expected), string.Join("|", result));
 			ObjectDumper.Write(query);
 		}
 
@@ -156,11 +187,17 @@ 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();
+
 			var query = from e in db.Employees
-						where e.FirstName.Contains("a")
-						select e.FirstName.IndexOf('A', 3);
+						let lowerName = e.FirstName.ToLower()
+						where lowerName.Contains("a")
+						select lowerName.IndexOf("a", 1);
+			var result = query.ToList();
 
+			Assert.That(result, Is.EqualTo(expected), "Expected {0} but was {1}", string.Join("|", expected), string.Join("|", result));
 			ObjectDumper.Write(query);
 		}
 

src/NHibernate/Dialect/Function/CharIndexFunction.cs

@@ -43,26 +43,38 @@ public SqlString Render(IList args, ISessionFactoryImplementor factory)
 			object start = threeArgs ? args[2] : null;
 
 			SqlStringBuilder buf = new SqlStringBuilder();
-			buf.Add("charindex(")
-				.AddObject(pattern)
-				.Add(", ");
 			if (threeArgs)
 			{
-				buf.Add("right(");
+				buf.Add("(case ");
+				RenderPositionInSubstring(buf, pattern, orgString, start);
+				buf.Add(" when 0 then 0 else (");
+				RenderPositionInSubstring(buf, pattern, orgString, start);
+				buf.Add("+(")
+				   .AddObject(start)
+				   .Add("-1)) end)");
 			}
-			buf.AddObject(orgString);
-			if (threeArgs)
+			else
 			{
-				buf.Add(", char_length(")
-					.AddObject(orgString)
-					.Add(")-(")
-					.AddObject(start)
-					.Add("-1))");
+				buf.Add("charindex(")
+				.AddObject(pattern)
+				.Add(", ")
+				.AddObject(orgString)
+				.Add(")");
 			}
-			buf.Add(")");
 			return buf.ToSqlString();
 		}
 
+		private static void RenderPositionInSubstring(SqlStringBuilder buf, object pattern, object orgString, object start)
+		{
+			buf.Add("charindex(")
+			   .AddObject(pattern)
+			   .Add(", right(")
+			   .AddObject(orgString)
+			   .Add(", char_length(")
+			   .AddObject(start)
+			   .Add(")))");
+		}
+
 		#endregion
 	}
 }

src/NHibernate/Dialect/Function/PositionSubstringFunction.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections;
 using System.Text;
+using Antlr.Runtime;
 using NHibernate.Engine;
 using NHibernate.SqlCommand;
 using NHibernate.Type;
@@ -49,32 +50,36 @@ public SqlString Render(IList args, ISessionFactoryImplementor factory)
 			SqlStringBuilder buf = new SqlStringBuilder();
 			if (threeArgs)
 			{
-				buf.Add("(");
-			}
-			buf.Add("position(")
-				.AddObject(pattern)
-				.Add(" in ");
-			if (threeArgs)
-			{
-				buf.Add("substring(");
-			}
-			buf.AddObject(orgString);
-			if (threeArgs)
-			{
-				buf.Add(", ")
-					.AddObject(start)
-					.Add(")");
+				buf.Add("(case ");
+				RenderPositionInSubstring(buf, pattern, orgString, start);
+				buf.Add(" when 0 then 0 else (");
+				RenderPositionInSubstring(buf, pattern, orgString, start);
+				buf.Add("+")
+				   .AddObject(start)
+				   .Add("-1) end)");
 			}
-			buf.Add(")");
-			if (threeArgs)
+			else
 			{
-				buf.Add("+")
-					.AddObject(start)
-					.Add("-1)");
+				buf.Add("position(")
+				.AddObject(pattern)
+				.Add(" in ")
+				.AddObject(orgString)
+				.Add(")");
 			}
 			return buf.ToSqlString();
 		}
 
+		private static void RenderPositionInSubstring(SqlStringBuilder buf, object pattern, object orgString, object start)
+		{
+			buf.Add("position(")
+			   .AddObject(pattern)
+			   .Add(" in substring(")
+			   .AddObject(orgString)
+			   .Add(", ")
+			   .AddObject(start)
+			   .Add("))");
+		}
+
 		#endregion
 	}
 }

src/NHibernate/Linq/Functions/StringGenerator.cs

@@ -196,17 +196,23 @@ public IndexOfGenerator()
 		}
 		public override HqlTreeNode BuildHql(MethodInfo method, Expression targetObject, ReadOnlyCollection<Expression> arguments, HqlTreeBuilder treeBuilder, IHqlExpressionVisitor visitor)
 		{
+			HqlMethodCall locate;
 			if (arguments.Count == 1)
 			{
-				return treeBuilder.MethodCall("locate",
-						visitor.Visit(arguments[0]).AsExpression(),
-						visitor.Visit(targetObject).AsExpression());//,
-						//treeBuilder.Constant(0));
-			}
-			return treeBuilder.MethodCall("locate",
+				locate = treeBuilder.MethodCall("locate",
 					visitor.Visit(arguments[0]).AsExpression(),
-					visitor.Visit(targetObject).AsExpression(),
-					visitor.Visit(arguments[1]).AsExpression());
+					visitor.Visit(targetObject).AsExpression()); //,
+				//treeBuilder.Constant(0));
+			}
+			else
+			{
+				var start = treeBuilder.Add(visitor.Visit(arguments[1]).AsExpression(), treeBuilder.Constant(1));
+				locate = treeBuilder.MethodCall("locate",
+							visitor.Visit(arguments[0]).AsExpression(),
+							visitor.Visit(targetObject).AsExpression(),
+							start);
+			}
+			return treeBuilder.Subtract(locate,treeBuilder.Constant(1));
 		}
 	}
 

src/NHibernate/Linq/Visitors/ExpressionParameterVisitor.cs

@@ -86,6 +86,7 @@ protected override Expression VisitConstantExpression(ConstantExpression express
 			if (!_parameters.ContainsKey(expression) && !typeof(IQueryable).IsAssignableFrom(expression.Type) && !IsNullObject(expression))
 			{
 				// We use null for the type to indicate that the caller should let HQL figure it out.
+				object value = expression.Value;
 				IType type = null;
 
 				// We have a bit more information about the null parameter value.
@@ -103,12 +104,18 @@ protected override Expression VisitConstantExpression(ConstantExpression express
 					}
 				}
 
+				// Constant characters should be sent as strings
+				if (expression.Type == typeof(char))
+				{
+					value = value.ToString();
+				}
+
 				// There is more information available in the Linq expression than to HQL directly.
 				// In some cases it might be advantageous to use the extra info.  Assuming this
 				// comes up, it would be nice to combine the HQL parameter type determination code
 				// and the Expression information.
 
-				_parameters.Add(expression, new NamedParameter("p" + (_parameters.Count + 1), expression.Value, type));
+				_parameters.Add(expression, new NamedParameter("p" + (_parameters.Count + 1), value, type));
 			}
 
 			return base.VisitConstantExpression(expression);