private HqlExpression GetExpressionForBooleanEquality(Expression @operator, HqlExpression original)
{
//When the expression is a constant then use the constant
var operandEx = @operator as ConstantExpression;
if (operandEx != null)
{
NamedParameter namedParameter;
if (_parameters.ConstantToParameterMap.TryGetValue(operandEx, out namedParameter))
{
_parameters.RequiredHqlParameters.Add(new NamedParameterDescriptor(namedParameter.Name, null, false));
return(_hqlTreeBuilder.Parameter(namedParameter.Name).AsExpression());
}
return(_hqlTreeBuilder.Constant(operandEx.Value));
}
//When the expression is a member-access not nullable then use the HbmDot
var memberAccessExpression = @operator as MemberExpression;
if (ExpressionType.MemberAccess.Equals(@operator.NodeType) && memberAccessExpression != null && typeof(bool) == memberAccessExpression.Type)
{
// this case make the difference when the property "Value" of a nullable type is used (ignore the null since the user is explicity checking the Value)
return(original);
}
var subQueryExpression = @operator as SubQueryExpression;
if (subQueryExpression != null)
{
var resultOperators = subQueryExpression.QueryModel.ResultOperators;
if (resultOperators.Count == 1 &&
(resultOperators[0] is FirstResultOperator ||
resultOperators[0] is SingleResultOperator))
{
return(original);
}
}
//When the expression is a member-access nullable then use the "case" clause to transform it to boolean (to use always .NET meaning instead leave the DB the behavior for null)
//When the expression is a complex-expression then use the "case" clause to transform it to boolean
return(_hqlTreeBuilder.Case(new[] { _hqlTreeBuilder.When(original, _hqlTreeBuilder.True()) }, _hqlTreeBuilder.False()));
}
internal static HqlExpression ToArithmeticExpression(this HqlTreeNode node)
{
var hqlBooleanExpression = node as HqlBooleanExpression;
if (hqlBooleanExpression != null)
{
var builder = new HqlTreeBuilder();
return(builder.Case(new[] { builder.When(hqlBooleanExpression, builder.True()) }, builder.False()));
}
return((HqlExpression)node);
}
private static HqlExpression ConvertBooleanToCase(HqlExpression node)
{
if (node is HqlBooleanExpression)
{
var builder = new HqlTreeBuilder();
return(builder.Case(
new HqlWhen[] { builder.When(node, builder.True()) },
builder.False()));
}
return(node);
}
protected HqlTreeNode VisitConditionalExpression(ConditionalExpression expression)
{
var test = VisitExpression(expression.Test).ToBooleanExpression();
var ifTrue = VisitExpression(expression.IfTrue).ToArithmeticExpression();
var ifFalse = (expression.IfFalse != null
? VisitExpression(expression.IfFalse).ToArithmeticExpression()
: null);
HqlExpression @case = _hqlTreeBuilder.Case(new[] { _hqlTreeBuilder.When(test, ifTrue) }, ifFalse);
return((expression.Type == typeof(bool) || expression.Type == (typeof(bool?)))
? @case
: _hqlTreeBuilder.Cast(@case, expression.Type));
}
protected HqlTreeNode VisitConditionalExpression(ConditionalExpression expression)
{
var test = VisitExpression(expression.Test).ToBooleanExpression();
var ifTrue = VisitExpression(expression.IfTrue).ToArithmeticExpression();
var ifFalse = (expression.IfFalse != null
? VisitExpression(expression.IfFalse).ToArithmeticExpression()
: null);
HqlExpression @case = _hqlTreeBuilder.Case(new[] { _hqlTreeBuilder.When(test, ifTrue) }, ifFalse);
// If both operands are parameters, HQL will not be able to determine the resulting type before
// parameters binding. But it has to compute result set columns type before parameters are bound,
// so an artificial cast is introduced to hint HQL at the resulting type.
return(expression.Type == typeof(bool) || expression.Type == typeof(bool?)
? @case
: _hqlTreeBuilder.TransparentCast(@case, expression.Type));
}
public override HqlTreeNode BuildHql(MethodInfo method, Expression targetObject, ReadOnlyCollection <Expression> arguments, HqlTreeBuilder treeBuilder, IHqlExpressionVisitor visitor)
{
// Instance a.CompareTo(b) or static string.Compare(a, b)?
Expression lhs = arguments.Count == 1 ? targetObject : arguments[0];
Expression rhs = arguments.Count == 1 ? arguments[0] : arguments[1];
HqlExpression lhs1 = visitor.Visit(lhs).AsExpression();
HqlExpression rhs1 = visitor.Visit(rhs).AsExpression();
HqlExpression lhs2 = visitor.Visit(lhs).AsExpression();
HqlExpression rhs2 = visitor.Visit(rhs).AsExpression();
// CASE WHEN (table.[Name] = N'Foo') THEN 0
// WHEN (table.[Name] > N'Foo') THEN 1
// ELSE -1 END
return(treeBuilder.Case(
new[]
{
treeBuilder.When(treeBuilder.Equality(lhs1, rhs1), treeBuilder.Constant(0)),
treeBuilder.When(treeBuilder.GreaterThan(lhs2, rhs2), treeBuilder.Constant(1))
},
treeBuilder.Constant(-1)));
}
public override HqlTreeNode BuildHql(MethodInfo method, Expression targetObject, ReadOnlyCollection <Expression> arguments, HqlTreeBuilder treeBuilder, IHqlExpressionVisitor visitor)
{
var when = treeBuilder.When(visitor.Visit(arguments[0]).AsExpression(), visitor.Visit(arguments[1]).AsExpression());
return(treeBuilder.Case(new[] { when }, visitor.Visit(arguments[2]).AsExpression()));
}
protected HqlTreeNode VisitBinaryExpression(BinaryExpression expression)
{
var lhs = VisitExpression(expression.Left).AsExpression();
var rhs = VisitExpression(expression.Right).AsExpression();
switch (expression.NodeType)
{
case ExpressionType.Equal:
// Need to check for boolean equality
if (lhs is HqlBooleanExpression || rhs is HqlBooleanExpression)
{
lhs =
_hqlTreeBuilder.Case(
new [] { _hqlTreeBuilder.When(lhs, _hqlTreeBuilder.Constant(1)) },
_hqlTreeBuilder.Constant(0));
rhs =
_hqlTreeBuilder.Case(
new [] { _hqlTreeBuilder.When(rhs, _hqlTreeBuilder.Constant(1)) },
_hqlTreeBuilder.Constant(0));
return(_hqlTreeBuilder.Equality(lhs, rhs));
}
// Also check for nullability
if (expression.Left.Type.IsNullableOrReference() || expression.Right.Type.IsNullableOrReference())
{
// TODO - yuck. This clone is needed because the AST tree nodes are not immutable,
// and sharing nodes between multiple branches will cause issues in the hqlSqlWalker phase -
// a node, x, gets visited during the walk and updated to refer to a real property. Later in
// the walk, x get revisited (since we copied it here), but now the type doesn't match what
// the parser expects. So we can't share. Implementing Clone() on HqlTreeNode would be better
// that doing a full visit of the Expression tree. Allowing shared nodes in the AST would be better
// still, but might be more work
var lhs2 = VisitExpression(expression.Left).AsExpression();
var rhs2 = VisitExpression(expression.Right).AsExpression();
return(_hqlTreeBuilder.BooleanOr(
_hqlTreeBuilder.BooleanAnd(
_hqlTreeBuilder.IsNull(lhs),
_hqlTreeBuilder.IsNull(rhs)),
_hqlTreeBuilder.Equality(lhs2, rhs2)
));
}
return(_hqlTreeBuilder.Equality(lhs, rhs));
case ExpressionType.NotEqual:
// Need to check for boolean in-equality
if (lhs is HqlBooleanExpression || rhs is HqlBooleanExpression)
{
lhs =
_hqlTreeBuilder.Case(
new [] { _hqlTreeBuilder.When(lhs, _hqlTreeBuilder.Constant(1)) },
_hqlTreeBuilder.Constant(0));
rhs =
_hqlTreeBuilder.Case(
new [] { _hqlTreeBuilder.When(rhs, _hqlTreeBuilder.Constant(1)) },
_hqlTreeBuilder.Constant(0));
return(_hqlTreeBuilder.Inequality(lhs, rhs));
}
// Also check for nullability
if (expression.Left.Type.IsNullableOrReference() || expression.Right.Type.IsNullableOrReference())
{
var lhs2 = VisitExpression(expression.Left).AsExpression();
var rhs2 = VisitExpression(expression.Right).AsExpression();
var lhs3 = VisitExpression(expression.Left).AsExpression();
var rhs3 = VisitExpression(expression.Right).AsExpression();
return
(_hqlTreeBuilder.BooleanOr(
_hqlTreeBuilder.BooleanOr(
_hqlTreeBuilder.BooleanAnd(
_hqlTreeBuilder.IsNull(lhs),
_hqlTreeBuilder.IsNotNull(rhs)),
_hqlTreeBuilder.BooleanAnd(
_hqlTreeBuilder.IsNotNull(lhs2),
_hqlTreeBuilder.IsNull(rhs2))
),
_hqlTreeBuilder.Inequality(lhs3, rhs3)));
}
return(_hqlTreeBuilder.Inequality(lhs, rhs));
case ExpressionType.And:
return(_hqlTreeBuilder.BitwiseAnd(lhs, rhs));
case ExpressionType.AndAlso:
return(_hqlTreeBuilder.BooleanAnd(lhs.AsBooleanExpression(), rhs.AsBooleanExpression()));
case ExpressionType.Or:
return(_hqlTreeBuilder.BitwiseOr(lhs, rhs));
case ExpressionType.OrElse:
return(_hqlTreeBuilder.BooleanOr(lhs.AsBooleanExpression(), rhs.AsBooleanExpression()));
case ExpressionType.Add:
return(_hqlTreeBuilder.Add(lhs, rhs));
case ExpressionType.Subtract:
return(_hqlTreeBuilder.Subtract(lhs, rhs));
case ExpressionType.Multiply:
return(_hqlTreeBuilder.Multiply(lhs, rhs));
case ExpressionType.Divide:
return(_hqlTreeBuilder.Divide(lhs, rhs));
case ExpressionType.LessThan:
return(_hqlTreeBuilder.LessThan(lhs, rhs));
case ExpressionType.LessThanOrEqual:
return(_hqlTreeBuilder.LessThanOrEqual(lhs, rhs));
case ExpressionType.GreaterThan:
return(_hqlTreeBuilder.GreaterThan(lhs, rhs));
case ExpressionType.GreaterThanOrEqual:
return(_hqlTreeBuilder.GreaterThanOrEqual(lhs, rhs));
}
throw new InvalidOperationException();
}
protected HqlTreeNode VisitBinaryExpression(BinaryExpression expression)
{
var lhs = VisitExpression(expression.Left).AsExpression();
var rhs = VisitExpression(expression.Right).AsExpression();
switch (expression.NodeType)
{
case ExpressionType.Equal:
// Need to check for boolean equality
if (lhs is HqlBooleanExpression || rhs is HqlBooleanExpression)
{
lhs =
_hqlTreeBuilder.Case(
new [] { _hqlTreeBuilder.When(lhs, _hqlTreeBuilder.Constant(true)) },
_hqlTreeBuilder.Constant(false));
rhs =
_hqlTreeBuilder.Case(
new [] { _hqlTreeBuilder.When(rhs, _hqlTreeBuilder.Constant(true)) },
_hqlTreeBuilder.Constant(false));
return(_hqlTreeBuilder.Equality(lhs, rhs));
}
// Check for nulls on left or right.
if (expression.Right is ConstantExpression &&
expression.Right.Type.IsNullableOrReference() &&
((ConstantExpression)expression.Right).Value == null)
{
return(_hqlTreeBuilder.IsNull(lhs));
}
if (expression.Left is ConstantExpression &&
expression.Left.Type.IsNullableOrReference() &&
((ConstantExpression)expression.Left).Value == null)
{
return(_hqlTreeBuilder.IsNull(rhs));
}
// Nothing was null, use standard equality.
return(_hqlTreeBuilder.Equality(lhs, rhs));
case ExpressionType.NotEqual:
// Need to check for boolean in-equality
if (lhs is HqlBooleanExpression || rhs is HqlBooleanExpression)
{
lhs =
_hqlTreeBuilder.Case(
new [] { _hqlTreeBuilder.When(lhs, _hqlTreeBuilder.Constant(true)) },
_hqlTreeBuilder.Constant(false));
rhs =
_hqlTreeBuilder.Case(
new [] { _hqlTreeBuilder.When(rhs, _hqlTreeBuilder.Constant(true)) },
_hqlTreeBuilder.Constant(false));
return(_hqlTreeBuilder.Inequality(lhs, rhs));
}
// Check for nulls on left or right.
if (expression.Right is ConstantExpression &&
expression.Right.Type.IsNullableOrReference() &&
((ConstantExpression)expression.Right).Value == null)
{
return(_hqlTreeBuilder.IsNotNull(lhs));
}
if (expression.Left is ConstantExpression &&
expression.Left.Type.IsNullableOrReference() &&
((ConstantExpression)expression.Left).Value == null)
{
return(_hqlTreeBuilder.IsNotNull(rhs));
}
// Nothing was null, use standard inequality.
return(_hqlTreeBuilder.Inequality(lhs, rhs));
case ExpressionType.And:
return(_hqlTreeBuilder.BitwiseAnd(lhs, rhs));
case ExpressionType.AndAlso:
return(_hqlTreeBuilder.BooleanAnd(lhs.AsBooleanExpression(), rhs.AsBooleanExpression()));
case ExpressionType.Or:
return(_hqlTreeBuilder.BitwiseOr(lhs, rhs));
case ExpressionType.OrElse:
return(_hqlTreeBuilder.BooleanOr(lhs.AsBooleanExpression(), rhs.AsBooleanExpression()));
case ExpressionType.Add:
return(_hqlTreeBuilder.Add(lhs, rhs));
case ExpressionType.Subtract:
return(_hqlTreeBuilder.Subtract(lhs, rhs));
case ExpressionType.Multiply:
return(_hqlTreeBuilder.Multiply(lhs, rhs));
case ExpressionType.Divide:
return(_hqlTreeBuilder.Divide(lhs, rhs));
case ExpressionType.LessThan:
return(_hqlTreeBuilder.LessThan(lhs, rhs));
case ExpressionType.LessThanOrEqual:
return(_hqlTreeBuilder.LessThanOrEqual(lhs, rhs));
case ExpressionType.GreaterThan:
return(_hqlTreeBuilder.GreaterThan(lhs, rhs));
case ExpressionType.GreaterThanOrEqual:
return(_hqlTreeBuilder.GreaterThanOrEqual(lhs, rhs));
case ExpressionType.Coalesce:
return(_hqlTreeBuilder.Coalesce(lhs, rhs));
}
throw new InvalidOperationException();
}