protected override Expression VisitSelect(SelectExpression select)
{
Visit(select.Where);
VisitOrderBy(select.OrderBy);
VisitFieldDeclarationList(select.Fields);
return select;
}
protected override Expression VisitSelect(SelectExpression select)
{
var newAlias = new Alias();
_map[select.Alias] = newAlias;
select = (SelectExpression)base.VisitSelect(select);
return new SelectExpression(newAlias, select.Fields, select.From, select.Where, select.OrderBy, select.GroupBy, select.IsDistinct, select.Skip, select.Take);
}
public ProjectionExpression(SelectExpression source, Expression projector, LambdaExpression aggregator)
: base(MongoExpressionType.Projection, aggregator != null ? aggregator.Body.Type : typeof(IEnumerable<>).MakeGenericType(projector.Type))
{
Source = source;
Projector = projector;
Aggregator = aggregator;
}
protected override Expression VisitSelect(SelectExpression select)
{
var saveIsOuterMostSelect = _isOutermostSelect;
try
{
_isOutermostSelect = false;
select = (SelectExpression)base.VisitSelect(select);
var hasOrderBy = select.OrderBy != null && select.OrderBy.Count > 0;
var hasGroupBy = select.GroupBy != null;
var canHaveOrderings = saveIsOuterMostSelect || select.Take != null || select.Skip != null;
var canReceivedOrderings = canHaveOrderings && !hasGroupBy && !select.IsDistinct;
if (hasOrderBy)
PrependOrderings(select.OrderBy);
IEnumerable<OrderExpression> orderings = null;
if (canReceivedOrderings)
orderings = _gatheredOrderings;
else if (canHaveOrderings)
orderings = select.OrderBy;
var canPassOnOrderings = !saveIsOuterMostSelect && !hasGroupBy && !select.IsDistinct;
ReadOnlyCollection<FieldDeclaration> fields = select.Fields;
if (_gatheredOrderings != null)
{
if (canPassOnOrderings)
{
var producedAliases = new DeclaredAliasGatherer().Gather(select.From);
BindResult project = RebindOrderings(_gatheredOrderings, select.Alias, producedAliases, select.Fields);
_gatheredOrderings = null;
PrependOrderings(project.Orderings);
fields = project.Fields;
}
else
_gatheredOrderings = null;
}
if (orderings != select.OrderBy || fields != select.Fields)
select = new SelectExpression(select.Alias, fields, select.From, select.Where, orderings, select.GroupBy, select.IsDistinct, select.Skip, select.Take);
return select;
}
finally
{
_isOutermostSelect = saveIsOuterMostSelect;
}
}
protected override Expression VisitSelect(SelectExpression select)
{
select = (SelectExpression)base.VisitSelect(select);
if (_lookup.Contains(select.Alias))
{
var fields = new List<FieldDeclaration>(select.Fields);
foreach (var ae in _lookup[select.Alias])
{
var name = "_$agg" + fields.Count;
var field = new FieldDeclaration(name, ae.AggregateInGroupSelect);
if (_map.ContainsKey(ae))
continue;
_map.Add(ae, new FieldExpression(ae.AggregateInGroupSelect, ae.GroupByAlias, name));
fields.Add(field);
}
return new SelectExpression(select.Alias, fields, select.From, select.Where, select.OrderBy, select.GroupBy, select.IsDistinct, select.Skip, select.Take);
}
return select;
}
protected override Expression VisitSelect(SelectExpression select)
{
bool wasTopLevel = _isTopLevel;
_isTopLevel = false;
select = (SelectExpression)base.VisitSelect(select);
while (CanMergeWithFrom(select, wasTopLevel))
{
var fromSelect = (SelectExpression)select.From;
select = (SelectExpression)new SubqueryRemover().Remove(select, new[] { fromSelect });
var where = select.Where;
if(fromSelect.Where != null)
{
if (where != null)
where = Expression.And(fromSelect.Where, where);
else
where = fromSelect.Where;
}
var groupBy = select.GroupBy ?? fromSelect.GroupBy;
var orderBy = select.OrderBy != null && select.OrderBy.Count > 0 ? select.OrderBy : fromSelect.OrderBy;
var skip = select.Skip ?? fromSelect.Skip;
var take = select.Take ?? fromSelect.Take;
bool distinct = select.IsDistinct | fromSelect.IsDistinct;
var fields = select.Fields.Count > 0 ? select.Fields : fromSelect.Fields;
if (where != select.Where
|| orderBy != select.OrderBy
|| groupBy != select.GroupBy
|| distinct != select.IsDistinct
|| skip != select.Skip
|| take != select.Take
|| fields != select.Fields)
{
select = new SelectExpression(select.Alias, fields, select.From, where, orderBy, groupBy, distinct, skip, take);
}
}
return select;
}
private static bool CanMergeWithFrom(SelectExpression select, bool isTopLevel)
{
var fromSelect = select.From as SelectExpression;
if (fromSelect == null)
return false;
var fromIsSimpleProjection = IsSimpleProjection(fromSelect);
var fromIsNameMapProjection = IsNameMapProjection(fromSelect);
if (!fromIsSimpleProjection && !fromIsNameMapProjection)
return false;
var selectIsNameMapProjection = IsNameMapProjection(select);
var selectHasOrderBy = select.OrderBy != null && select.OrderBy.Count > 0;
var selectHasGroupBy = select.GroupBy != null;
var selectHasAggregates = new AggregateChecker().HasAggregates(select);
var fromHasOrderBy = fromSelect.OrderBy != null && fromSelect.OrderBy.Count > 0;
var fromHasGroupBy = fromSelect.GroupBy != null;
if (selectHasOrderBy && fromHasOrderBy)
return false;
if (selectHasGroupBy && fromHasGroupBy)
return false;
if(fromHasOrderBy && (selectHasGroupBy || selectHasAggregates || select.IsDistinct))
return false;
if(fromHasGroupBy && select.Where != null)
return false;
if(fromSelect.Take != null && (select.Take != null || select.Skip != null || select.IsDistinct || selectHasAggregates || selectHasGroupBy))
return false;
if(fromSelect.Skip != null && (select.Skip != null || select.IsDistinct || selectHasAggregates || selectHasGroupBy))
return false;
if (fromSelect.IsDistinct && (select.Take != null || select.Skip != null || !selectIsNameMapProjection || selectHasGroupBy || selectHasAggregates || (selectHasOrderBy && !isTopLevel)))
return false;
return true;
}
protected override Expression VisitSelect(SelectExpression select)
{
select = (SelectExpression)base.VisitSelect(select);
var fields = select.Fields.OrderBy(f => f.Name).ToList();
var removed = new BitArray(fields.Count);
var anyRemoved = false;
for (int i = 0, n = fields.Count; i < n; i++)
{
var fi = fields[i];
var fxi = new FieldExpression(fi.Expression, select.Alias, fi.Name);
for (int j = i + 1; j < n; j++)
{
if (!removed.Get(i))
{
FieldDeclaration fj = fields[j];
if (AreSameExpression(fi.Expression, fj.Expression))
{
var fxj = new FieldExpression(fj.Expression, select.Alias, fj.Name);
_map.Add(fxj, fxi);
removed.Set(j, true);
anyRemoved = true;
}
}
}
}
if (anyRemoved)
{
var newFields = new List<FieldDeclaration>();
for (int i = 0, n = fields.Count; i < n; i++)
{
if (!removed.Get(i))
newFields.Add(fields[i]);
}
select = select.SetFields(newFields);
}
return select;
}
protected virtual bool CompareSelect(SelectExpression a, SelectExpression b)
{
var save = _aliasScope;
try
{
if (!Compare(a.From, b.From))
return false;
_aliasScope = new ScopedDictionary<Alias, Alias>(save);
MapAliases(a.From, b.From);
return Compare(a.Where, b.Where)
&& CompareOrderList(a.OrderBy, b.OrderBy)
&& Compare(a.GroupBy, b.GroupBy)
&& Compare(a.Skip, b.Skip)
&& Compare(a.Take, b.Take)
&& a.IsDistinct == b.IsDistinct
&& CompareFieldDeclarations(a.Fields, b.Fields);
}
finally
{
_aliasScope = save;
}
}
public ScalarExpression(Type type, SelectExpression select)
: base(MongoExpressionType.Scalar, type, select)
{ }
protected virtual Expression VisitSelect(SelectExpression select)
{
var from = VisitSource(select.From);
var where = Visit(select.Where);
var groupBy = Visit(select.GroupBy);
var orderBy = VisitOrderBy(select.OrderBy);
var skip = Visit(select.Skip);
var take = Visit(select.Take);
var fields = VisitFieldDeclarationList(select.Fields);
if (from != select.From || where != select.Where || orderBy != select.OrderBy || groupBy != select.GroupBy || skip != select.Skip || take != select.Take || fields != select.Fields)
return new SelectExpression(select.Alias, fields, from, where, orderBy, groupBy, select.IsDistinct, skip, take);
return select;
}
private Expression BindAggregate(Expression source, MethodInfo method, LambdaExpression argument, bool isRoot)
{
var returnType = method.ReturnType;
var aggregateType = GetAggregateType(method.Name);
bool hasPredicateArgument = HasPredicateArgument(aggregateType);
bool distinct = false;
bool argumentWasPredicate = false;
var methodCallExpression = source as MethodCallExpression;
if (methodCallExpression != null && !hasPredicateArgument && argument == null)
{
if (methodCallExpression.Method.Name == "Distinct" && methodCallExpression.Arguments.Count == 1
&& (methodCallExpression.Method.DeclaringType == typeof(Queryable) || methodCallExpression.Method.DeclaringType == typeof(Enumerable)))
{
source = methodCallExpression.Arguments[0];
distinct = true;
}
}
if (argument != null && hasPredicateArgument)
{
source = Expression.Call(typeof(Queryable), "Where", method.GetGenericArguments(), source, argument);
argument = null;
argumentWasPredicate = true;
}
var projection = VisitSequence(source);
Expression argExpression = null;
if (argument != null)
{
_map[argument.Parameters[0]] = projection.Projector;
argExpression = Visit(argument.Body);
}
else if (!hasPredicateArgument)
argExpression = projection.Projector;
var alias = new Alias();
Expression aggregateExpression = new AggregateExpression(returnType, aggregateType, argExpression, distinct);
var selectType = typeof(IEnumerable<>).MakeGenericType(returnType);
string fieldName = "_$agg" + (_aggregateCount++);
var select = new SelectExpression(alias, new[] { new FieldDeclaration(fieldName, aggregateExpression) }, projection.Source, null);
if (isRoot)
{
var parameter = Expression.Parameter(selectType, "p");
var lambda = Expression.Lambda(Expression.Call(typeof(Enumerable), "Single", new[] { returnType }, parameter), parameter);
return new ProjectionExpression(
select,
new FieldExpression(aggregateExpression, alias, fieldName),
lambda);
}
var subquery = new ScalarExpression(returnType, select);
GroupByInfo info;
if (!argumentWasPredicate && _groupByMap.TryGetValue(projection, out info))
{
if (argument != null)
{
_map[argument.Parameters[0]] = info.Element;
argExpression = Visit(argument.Body);
}
else if (!hasPredicateArgument)
argExpression = info.Element;
aggregateExpression = new AggregateExpression(returnType, aggregateType, argExpression, distinct);
if (projection == _currentGroupElement)
return aggregateExpression;
return new AggregateSubqueryExpression(info.Alias, aggregateExpression, subquery);
}
return subquery;
}
public ProjectionExpression(SelectExpression source, Expression projector)
: this(source, projector, null)
{
}
protected SubqueryExpression(MongoExpressionType nodeType, Type type, SelectExpression select)
: base(nodeType, type)
{
Select = select;
}
protected override Expression VisitSelect(SelectExpression select)
{
_aliases.Add(select.Alias);
return select;
}
protected override Expression VisitSelect(SelectExpression select)
{
VisitFieldDeclarationList(select.Fields);
return select;
}
protected override Expression VisitSelect(SelectExpression s)
{
return _selectsToRemove.Contains(s) ? Visit(s.From) : base.VisitSelect(s);
}
protected SubqueryExpression(MongoExpressionType nodeType, Type type, SelectExpression select)
: base(nodeType, type)
{
Select = select;
}
public Expression Remove(SelectExpression outerSelect, IEnumerable<SelectExpression> selectsToRemove)
{
_selectsToRemove = new HashSet<SelectExpression>(selectsToRemove);
return Visit(outerSelect);
}
private static bool IsUniqueName(SelectExpression select, string name)
{
return select.Fields.All(field => field.Name != name);
}
public ProjectionExpression(SelectExpression source, Expression projector)
: this(source, projector, null)
{ }
private static bool IsSimpleProjection(SelectExpression select)
{
return select.Fields.All(field => !string.IsNullOrEmpty(field.Name));
}
private static bool IsNameMapProjection(SelectExpression select)
{
var fromSelect = select.From as SelectExpression;
if (select.Fields.Count == 0)
return true;
if (fromSelect == null || select.Fields.Count != fromSelect.Fields.Count)
return false;
for (int i = 0, n = select.Fields.Count; i < n; i++)
{
if (select.Fields[i].Name != fromSelect.Fields[i].Name)
return false;
}
return true;
}
