internal LinkOptimizationScope(LinkOptimizationScope previous) {
this.previous = previous;
}
internal override SqlSelect VisitSelect(SqlSelect select) {
LinkOptimizationScope saveScope = this.linkMap;
SqlSelect saveSelect = this.currentSelect;
bool saveInGroupBy = inGroupBy;
inGroupBy = false;
try {
// don't preserve any link optimizations across a group or distinct boundary
bool linkOptimize = true;
if (this.binder.optimizeLinkExpansions &&
(select.GroupBy.Count > 0 || this.aggregateChecker.HasAggregates(select) || select.IsDistinct)) {
linkOptimize = false;
this.linkMap = new LinkOptimizationScope(this.linkMap);
}
select.From = this.VisitSource(select.From);
this.currentSelect = select;
select.Where = this.VisitExpression(select.Where);
this.inGroupBy = true;
for (int i = 0, n = select.GroupBy.Count; i < n; i++) {
select.GroupBy[i] = this.VisitExpression(select.GroupBy[i]);
}
this.inGroupBy = false;
select.Having = this.VisitExpression(select.Having);
for (int i = 0, n = select.OrderBy.Count; i < n; i++) {
select.OrderBy[i].Expression = this.VisitExpression(select.OrderBy[i].Expression);
}
select.Top = this.VisitExpression(select.Top);
select.Row = (SqlRow)this.Visit(select.Row);
select.Selection = this.VisitExpression(select.Selection);
select.Selection = this.columnizer.ColumnizeSelection(select.Selection);
if (linkOptimize) {
select.Selection = ConvertLinks(select.Selection);
}
// optimize out where clause for WHERE TRUE
if (select.Where != null && select.Where.NodeType == SqlNodeType.Value && (bool)((SqlValue)select.Where).Value) {
select.Where = null;
}
}
finally {
this.currentSelect = saveSelect;
this.linkMap = saveScope;
this.inGroupBy = saveInGroupBy;
}
return select;
}
internal override SqlExpression VisitSubSelect(SqlSubSelect ss) {
// don't preserve any link optimizations across sub-queries
LinkOptimizationScope saveScope = this.linkMap;
SqlSelect saveSelect = this.currentSelect;
try {
this.linkMap = new LinkOptimizationScope(this.linkMap);
this.currentSelect = null;
return base.VisitSubSelect(ss);
}
finally {
this.linkMap = saveScope;
this.currentSelect = saveSelect;
}
}
internal Visitor(SqlBinder binder, Translator translator, SqlColumnizer columnizer, SqlFactory sqlFactory, MetaModel model, DataLoadOptions shape, bool canUseOuterApply) {
this.binder = binder;
this.translator = translator;
this.columnizer = columnizer;
this.sql = sqlFactory;
this.typeProvider = sqlFactory.TypeProvider;
this.expander = new SqlExpander(this.sql);
this.aggregateChecker = new SqlAggregateChecker();
this.linkMap = new LinkOptimizationScope(null);
this.outerAliasMap = new Dictionary<SqlAlias, SqlAlias>();
this.model = model;
this.shape = shape;
this.canUseOuterApply = canUseOuterApply;
}
