protected override Expression VisitConditional(ConditionalExpression expression)
{
var test = this.Visit(expression.Test);
var ifFalse = this.Visit(expression.IfFalse);
var ifTrue = this.Visit(expression.IfTrue);
if (test is BitBooleanExpression)
{
test = Expression.Equal(test, Expression.Constant(true, test.Type));
}
if (ifFalse.Type.GetUnwrappedNullableType() == typeof(bool) && !(ifFalse is BitBooleanExpression))
{
ifFalse = BitBooleanExpression.Coerce(ifFalse);
}
if (ifTrue.Type.GetUnwrappedNullableType() == typeof(bool) && !(ifTrue is BitBooleanExpression))
{
ifTrue = BitBooleanExpression.Coerce(ifTrue);
}
if (test != expression.Test || ifFalse != expression.IfFalse || ifTrue != expression.IfTrue)
{
return(new BitBooleanExpression(Expression.Condition(test, ifTrue, ifFalse)));
}
else
{
return(base.VisitConditional(expression));
}
}
protected override Expression VisitSelect(SqlSelectExpression selectExpression)
{
var count = selectExpression.Columns.Count;
List <SqlColumnDeclaration> newColumns = null;
for (var i = 0; i < count; i++)
{
var column = selectExpression.Columns[i];
var visitedColumnExpression = this.Visit(column.Expression);
if (visitedColumnExpression.Type.GetUnwrappedNullableType() == typeof(bool) && !(visitedColumnExpression is BitBooleanExpression))
{
if (newColumns == null)
{
newColumns = new List <SqlColumnDeclaration>(selectExpression.Columns.Take(i));
}
var newColumnExpression = BitBooleanExpression.Coerce(visitedColumnExpression);
var newColumnDeclaration = new SqlColumnDeclaration(column.Name, newColumnExpression);
newColumns.Add(newColumnDeclaration);
}
else if (visitedColumnExpression != column.Expression)
{
if (newColumns == null)
{
newColumns = new List <SqlColumnDeclaration>(selectExpression.Columns.Take(i));
}
newColumns.Add(column.ReplaceExpression(visitedColumnExpression));
}
else if (newColumns != null)
{
newColumns.Add(column);
}
}
var from = this.VisitSource(selectExpression.From);
var where = this.Visit(selectExpression.Where);
var orderBy = this.VisitExpressionList(selectExpression.OrderBy);
var groupBy = this.VisitExpressionList(selectExpression.GroupBy);
var skip = this.Visit(selectExpression.Skip);
var take = this.Visit(selectExpression.Take);
if (where is BitBooleanExpression)
{
where = Expression.Equal(where, Expression.Constant(true, where.Type));
}
if (from != selectExpression.From || where != selectExpression.Where || newColumns != selectExpression.Columns || orderBy != selectExpression.OrderBy || groupBy != selectExpression.GroupBy || take != selectExpression.Take || skip != selectExpression.Skip)
{
return(new SqlSelectExpression(selectExpression.Type, selectExpression.Alias, newColumns ?? selectExpression.Columns, from, where, orderBy, groupBy, selectExpression.Distinct, skip, take, selectExpression.ForUpdate, selectExpression.Reverse, selectExpression.Into));
}
return(base.VisitSelect(selectExpression));
}
public static BitBooleanExpression Coerce(Expression expression)
{
var nullable = expression.Type == typeof(bool?);
var retval = new BitBooleanExpression(Condition(expression, new BitBooleanExpression(Constant(true, nullable ? typeof(bool?) : typeof(bool))), new BitBooleanExpression(Constant(false, nullable ? typeof(bool?) : typeof(bool)))));
if (nullable)
{
retval = new BitBooleanExpression(Condition(Equal(retval, Constant(null)), Constant(null, typeof(bool?)), retval));
}
return(retval);
}
public static BitBooleanExpression Coerce(Expression expression)
{
var nullable = expression.Type == typeof(bool?);
var retval = new BitBooleanExpression(Condition(expression, new BitBooleanExpression(Constant(true, nullable ? typeof(bool?) : typeof(bool))), new BitBooleanExpression(Constant(false, nullable ? typeof(bool?) : typeof(bool)))));
if (nullable)
{
retval = new BitBooleanExpression(Condition(Equal(retval, Constant(null)), Constant(null, typeof(bool?)), retval));
}
return retval;
}
protected override Expression VisitSelect(SqlSelectExpression selectExpression)
{
List <SqlColumnDeclaration> newColumns = null;
for (var i = 0; i < selectExpression.Columns.Count; i++)
{
var column = selectExpression.Columns[i];
var visitedColumnExpression = this.Visit(column.Expression);
if (visitedColumnExpression.Type.GetUnwrappedNullableType() == typeof(bool) && !(visitedColumnExpression is BitBooleanExpression))
{
if (newColumns == null)
{
newColumns = new List <SqlColumnDeclaration>(selectExpression.Columns.Take(i));
}
var newColumnExpression = BitBooleanExpression.Coerce(visitedColumnExpression);
var newColumnDeclaration = new SqlColumnDeclaration(column.Name, newColumnExpression);
newColumns.Add(newColumnDeclaration);
}
else if (visitedColumnExpression != column.Expression)
{
if (newColumns == null)
{
newColumns = new List <SqlColumnDeclaration>(selectExpression.Columns.Take(i));
}
newColumns.Add(column.ReplaceExpression(visitedColumnExpression));
}
else if (newColumns != null)
{
newColumns.Add(column);
}
}
var where = this.Visit(selectExpression.Where);
if ((where is BitBooleanExpression))
{
where = Expression.Equal(where, Expression.Constant(true));
}
if (where != selectExpression.Where)
{
if (newColumns != null)
{
return(selectExpression.ChangeWhereAndColumns(where, new ReadOnlyList <SqlColumnDeclaration>(newColumns)));
}
else
{
return(selectExpression.ChangeWhere(where));
}
}
else if (newColumns != null)
{
return(selectExpression.ChangeColumns(newColumns, true));
}
else
{
return(base.VisitSelect(selectExpression));
}
}
