internal GroupPartitionInfo(
GroupPartitionExpr groupPartitionExpr, ErrorContext errCtx, GroupAggregateInfo containingAggregate,
ScopeRegion definingScopeRegion)
: base(GroupAggregateKind.Partition, groupPartitionExpr, errCtx, containingAggregate, definingScopeRegion)
{
Debug.Assert(groupPartitionExpr != null, "groupPartitionExpr != null");
}
protected GroupAggregateInfo(
GroupAggregateKind aggregateKind,
GroupAggregateExpr astNode,
ErrorContext errCtx,
GroupAggregateInfo containingAggregate,
ScopeRegion definingScopeRegion)
{
Debug.Assert(aggregateKind != GroupAggregateKind.None, "aggregateKind != GroupAggregateKind.None");
Debug.Assert(errCtx != null, "errCtx != null");
Debug.Assert(definingScopeRegion != null, "definingScopeRegion != null");
AggregateKind = aggregateKind;
AstNode = astNode;
ErrCtx = errCtx;
DefiningScopeRegion = definingScopeRegion;
SetContainingAggregate(containingAggregate);
}
/// <summary>
/// Function call is _allowed_ after <see cref="ValidateAndComputeEvaluatingScopeRegion"/> has been called.
/// Removing contained aggregates cannot invalidate the current aggregate.
///
/// Consider the following query:
///
/// select value max(a + anyelement(select value max(b + max(a + anyelement(select value c1
/// from {2} as c group by c as c1)))
/// from {1} as b group by b as b1))
/// from {0} as a group by a as a1
///
/// Outer aggregate - max1, middle aggregate - max2, inner aggregate - max3.
/// In this query after max1 have been processed as a collection function, max2 and max3 are wired as containing/contained.
/// There is a point later when max1 is processed as an aggregate, max2 is processed as a collection function and max3 is processed as
/// an aggregate. Note that at this point the "aggregate" version of max2 is dropped and detached from the AST node when the middle scope region
/// completes processing; also note that because evaluating scope region of max3 is the outer scope region, max3 aggregate info is still attached to
/// the AST node and it is still wired to the dropped aggregate info object of max2. At this point max3 does not see new max2 as a containing aggregate,
/// and it rewires to max1, during this rewiring it needs to to remove itself from the old max2 and add itself to max1.
/// The old max2 at this point is sealed, so the removal is performed on the sealed object.
/// </summary>
private void RemoveContainedAggregate(GroupAggregateInfo containedAggregate)
{
Debug.Assert(
_containedAggregates != null && _containedAggregates.Contains(containedAggregate),
"_containedAggregates.Contains(containedAggregate)");
_containedAggregates.Remove(containedAggregate);
}
/// <summary>
/// Function call is not allowed after <see cref="ValidateAndComputeEvaluatingScopeRegion"/> has been called.
/// Adding new contained aggregate may invalidate the current aggregate.
/// </summary>
private void AddContainedAggregate(GroupAggregateInfo containedAggregate)
{
Debug.Assert(_evaluatingScopeRegion == null, "Can not add contained aggregate after _evaluatingScopeRegion have been computed.");
if (_containedAggregates == null)
{
_containedAggregates = new List<GroupAggregateInfo>();
}
Debug.Assert(_containedAggregates.Contains(containedAggregate) == false, "containedAggregate is already registered");
_containedAggregates.Add(containedAggregate);
}
internal void SetContainingAggregate(GroupAggregateInfo containingAggregate)
{
if (_containingAggregate != null)
{
//
// Aggregates in this query
//
// select value max(anyelement(select value max(b + max(a + anyelement(select value c1
// from {2} as c group by c as c1)))
// from {1} as b group by b as b1))
//
// from {0} as a group by a as a1
//
// are processed in the following steps:
// 1. the outermost aggregate (max1) begins processing as a collection function;
// 2. the middle aggregate (max2) begins processing as a collection function;
// 3. the innermost aggregate (max3) is processed as a collection function;
// 4. max3 is reprocessed as an aggregate; it does not see any containing aggregates at this point, so it's not wired up;
// max3 is validated and sealed;
// evaluating scope region for max3 is the outermost scope region, to which it gets assigned;
// max3 aggregate info object is attached to the corresponding AST node;
// 5. max2 completes processing as a collection function and begins processing as an aggregate;
// 6. max3 is reprocessed as an aggregate in the SemanticAnalyzer.TryConvertAsResolvedGroupAggregate(...) method, and
// wired up to max2 as contained/containing;
// 7. max2 completes processing as an aggregate;
// max2 is validated and sealed;
// note that max2 does not see any containing aggregates at this point, so it's wired up only to max3;
// evaluating scope region for max2 is the middle scope region to which it gets assigned;
// 6. middle scope region completes processing, yields a DbExpression and cleans up all aggregate info objects assigned to it (max2);
// max2 is detached from the corresponding AST node;
// at this point max3 is still assigned to the outermost scope region and still wired to the dropped max2 as containing/contained;
// 7. max1 completes processing as a collection function and begins processing as an aggregate;
// 8. max2 is revisited and begins processing as a collection function (note that because the old aggregate info object for max2 was dropped
// and detached from the AST node in step 6, SemanticAnalyzer.TryConvertAsResolvedGroupAggregate(...) does not recognize max2 as an aggregate);
// 9. max3 is recognized as an aggregate in the SemanticAnalyzer.TryConvertAsResolvedGroupAggregate(...) method;
// max3 is rewired from the dropped max2 (step 6) to max1 as contained/containing, now max1 and max3 are wired as containing/contained;
// 10. max2 completes processing as a collection function and begins processing as an aggregate;
// max2 sees max1 as a containing aggregate and wires to it;
// 11. max3 is reprocessed as resolved aggregate inside of TryConvertAsResolvedGroupAggregate(...) method;
// max3 is rewired from max1 to max2 as containing/contained aggregate;
// 12. at this point max1 is wired to max2 and max2 is wired to max3, the tree is correct;
//
// ... both max1 and max3 are assigned to the same scope for evaluation, this is detected and an error is reported;
//
//
// Remove this aggregate from the old containing aggregate before rewiring to the new parent.
//
_containingAggregate.RemoveContainedAggregate(this);
}
//
// Accept the new parent and wire to it as a contained aggregate.
//
_containingAggregate = containingAggregate;
if (_containingAggregate != null)
{
_containingAggregate.AddContainedAggregate(this);
}
}
internal FunctionAggregateInfo(
MethodExpr methodExpr, ErrorContext errCtx, GroupAggregateInfo containingAggregate, ScopeRegion definingScopeRegion)
: base(GroupAggregateKind.Function, methodExpr, errCtx, containingAggregate, definingScopeRegion)
{
Debug.Assert(methodExpr != null, "methodExpr != null");
}
