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Refactor RelationalProjectionExpressionVisitor
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More accurate marking of RequiresClientProjection (less false positives), which results in less duplicate visitation of child query models in many cases

Fixes #7844
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@tuespetre
tuespetre committed Mar 15, 2017
1 parent 03a990c commit 6ce36d4
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Showing 3 changed files with 227 additions and 155 deletions.
267 changes: 167 additions & 100 deletions src/EFCore.Relational/Query/ExpressionVisitors/RelationalProjectionExpressionVisitor.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -50,66 +50,98 @@ public RelationalProjectionExpressionVisitor(
/// <summary>
/// Visit a method call expression.
/// </summary>
/// <param name="node"> The expression to visit. </param>
/// <param name="methodCallExpression"> The expression to visit. </param>
/// <returns>
/// An Expression corresponding to the translated method call.
/// </returns>
protected override Expression VisitMethodCall(MethodCallExpression node)
protected override Expression VisitMethodCall(MethodCallExpression methodCallExpression)
{
Check.NotNull(node, nameof(node));
Check.NotNull(methodCallExpression, nameof(methodCallExpression));

var sqlExpression = TranslateExpression(methodCallExpression);

var objectExpression
= EntityQueryModelVisitor.IsPropertyMethod(methodCallExpression.Method)
? methodCallExpression.Arguments[0].RemoveConvert()
: methodCallExpression.Object;

var handledExpression
= TryHandleMemberOrMethodCallExpression(
methodCallExpression,
objectExpression,
sqlExpression);

if (EntityQueryModelVisitor.IsPropertyMethod(node.Method))
if (handledExpression != null)
{
var newArg0 = Visit(node.Arguments[0]);
return handledExpression;
}

if (newArg0 != node.Arguments[0])
{
return Expression.Call(
node.Method,
newArg0,
node.Arguments[1]);
}
QueryModelVisitor.RequiresClientProjection = true;
return methodCallExpression;
}

/// <summary>
/// Visit a member expression.
/// </summary>
/// <param name="memberExpression"> The expression to visit. </param>
/// <returns>
/// An Expression corresponding to the translated member.
/// </returns>
protected override Expression VisitMember(MemberExpression memberExpression)
{
Check.NotNull(memberExpression, nameof(memberExpression));

var sqlExpression = TranslateExpression(memberExpression);

return node;
var handledExpression
= TryHandleMemberOrMethodCallExpression(
memberExpression,
memberExpression.Expression.RemoveConvert(),
sqlExpression);

if (handledExpression != null)
{
return handledExpression;
}

return base.VisitMethodCall(node);
QueryModelVisitor.RequiresClientProjection = true;
return memberExpression;
}

/// <summary>
/// Visit a new expression.
/// </summary>
/// <param name="expression"> The expression to visit. </param>
/// <param name="newExpression"> The expression to visit. </param>
/// <returns>
/// An Expression corresponding to the translated new expression.
/// </returns>
protected override Expression VisitNew(NewExpression expression)
protected override Expression VisitNew(NewExpression newExpression)
{
Check.NotNull(expression, nameof(expression));
Check.NotNull(newExpression, nameof(newExpression));

var newNewExpression = base.VisitNew(expression);
var visitedNewExpression = base.VisitNew(newExpression);

var selectExpression = QueryModelVisitor.TryGetQuery(_querySource);

if (selectExpression != null)
{
for (var i = 0; i < expression.Arguments.Count; i++)
for (var i = 0; i < newExpression.Arguments.Count; i++)
{
var aliasExpression
= selectExpression.Projection
.OfType<AliasExpression>()
.SingleOrDefault(ae => ae.SourceExpression == expression.Arguments[i]);
.SingleOrDefault(ae => ae.SourceExpression == newExpression.Arguments[i]);

if (aliasExpression != null)
{
aliasExpression.SourceMember
= expression.Members?[i]
?? (expression.Arguments[i] as MemberExpression)?.Member;
= newExpression.Members?[i]
?? (newExpression.Arguments[i] as MemberExpression)?.Member;
}
}
}

return newNewExpression;
return visitedNewExpression;
}

/// <summary>
Expand All @@ -121,113 +153,148 @@ var aliasExpression
/// </returns>
public override Expression Visit(Expression node)
{
if (node == null)
{
return null;
}

if (node is ConstantExpression
|| node is NewExpression
|| node is MemberExpression
|| node is MethodCallExpression)
{
return base.Visit(node);
}

var selectExpression = QueryModelVisitor.TryGetQuery(_querySource);

if (node != null
&& !(node is ConstantExpression)
&& selectExpression != null)
if (selectExpression == null)
{
var existingProjectionsCount = selectExpression.Projection.Count;
return base.Visit(node);
}

var sqlExpression
= _sqlTranslatingExpressionVisitorFactory
.Create(QueryModelVisitor, selectExpression, inProjection: true)
.Visit(node);
var sqlExpression = TranslateExpression(node);

if (sqlExpression == null)
if (sqlExpression == null)
{
if (node is QuerySourceReferenceExpression qsre)
{
var qsre = node as QuerySourceReferenceExpression;
if (qsre == null)
{
QueryModelVisitor.RequiresClientProjection = true;
}
else
if (QueryModelVisitor.ParentQueryModelVisitor != null)
{
if (QueryModelVisitor.ParentQueryModelVisitor != null
&& selectExpression.HandlesQuerySource(qsre.ReferencedQuerySource))
{
selectExpression.ProjectStarTable = selectExpression.GetTableForQuerySource(qsre.ReferencedQuerySource);
}
selectExpression.ProjectStarTable
= selectExpression.GetTableForQuerySource(qsre.ReferencedQuerySource);
}
}
else
{
selectExpression.RemoveRangeFromProjection(existingProjectionsCount);
QueryModelVisitor.RequiresClientProjection = true;
}

if (!(node is NewExpression))
{
AliasExpression aliasExpression;
return base.Visit(node);
}

int index;
if (!(node is QuerySourceReferenceExpression))
{
if (sqlExpression is NullableExpression nullableExpression)
{
sqlExpression = nullableExpression.Operand;
}

if (!(node is QuerySourceReferenceExpression))
{
if (sqlExpression is NullableExpression nullableExpression)
{
sqlExpression = nullableExpression.Operand;
}
if (sqlExpression.TryGetColumnExpression() != null)
{
var index = selectExpression.AddToProjection(sqlExpression);

var columnExpression = sqlExpression.TryGetColumnExpression();
if (selectExpression.Projection[index] is AliasExpression aliasExpression)
{
aliasExpression.SourceExpression = node;
}

if (columnExpression != null)
{
index = selectExpression.AddToProjection(sqlExpression);
return node;
}
}

aliasExpression = selectExpression.Projection[index] as AliasExpression;
if (!(sqlExpression is ConstantExpression))
{
var targetExpression
= QueryModelVisitor.QueryCompilationContext.QuerySourceMapping
.GetExpression(_querySource);

if (aliasExpression != null)
{
aliasExpression.SourceExpression = node;
}
return targetExpression.Type == typeof(ValueBuffer)
? CreateReadValueExpression(node, targetExpression, selectExpression, sqlExpression)
: node;
}

return node;
}
}
return base.Visit(node);
}

if (!(sqlExpression is ConstantExpression))
{
var targetExpression
= QueryModelVisitor.QueryCompilationContext.QuerySourceMapping
.GetExpression(_querySource);
private Expression TranslateExpression(Expression expression)
=> _sqlTranslatingExpressionVisitorFactory
.Create(QueryModelVisitor, inProjection: true)
.Visit(expression);

private Expression TryHandleMemberOrMethodCallExpression(
Expression node, Expression objectExpression, Expression sqlExpression)
{
if (sqlExpression == null)
{
return null;
}

if (targetExpression.Type == typeof(ValueBuffer))
{
index = selectExpression.AddToProjection(sqlExpression);
Expression targetExpression = null;
SelectExpression targetQuery = null;

aliasExpression = selectExpression.Projection[index] as AliasExpression;
if (objectExpression is QuerySourceReferenceExpression qsre)
{
targetExpression
= QueryModelVisitor.QueryCompilationContext.QuerySourceMapping
.GetExpression(qsre.ReferencedQuerySource);

if (aliasExpression != null)
{
aliasExpression.SourceExpression = node;
}
targetQuery
= QueryModelVisitor.TryGetQuery(qsre.ReferencedQuerySource);
}

var readValueExpression
= _entityMaterializerSource
.CreateReadValueCallExpression(targetExpression, index);
if (targetQuery == null)
{
targetExpression
= QueryModelVisitor.QueryCompilationContext.QuerySourceMapping
.GetExpression(_querySource);

var outputDataInfo
= (node as SubQueryExpression)?.QueryModel
.GetOutputDataInfo();
targetQuery
= QueryModelVisitor.TryGetQuery(_querySource);
}

if (outputDataInfo is StreamedScalarValueInfo)
{
// Compensate for possible nulls
readValueExpression
= Expression.Coalesce(
readValueExpression,
Expression.Default(node.Type));
}
return targetQuery != null && targetExpression.Type == typeof(ValueBuffer)
? CreateReadValueExpression(node, targetExpression, targetQuery, sqlExpression)
: node;
}

return Expression.Convert(readValueExpression, node.Type);
}
private Expression CreateReadValueExpression(
Expression node,
Expression targetExpression,
SelectExpression selectExpression,
Expression sqlExpression)
{
var index = selectExpression.AddToProjection(sqlExpression);

return node;
}
}
}
if (selectExpression.Projection[index] is AliasExpression aliasExpression)
{
aliasExpression.SourceExpression = node;
}

return base.Visit(node);
if (node is SubQueryExpression subQueryExpression
&& subQueryExpression.QueryModel.GetOutputDataInfo() is StreamedScalarValueInfo)
{
// Compensate for possible nulls
return Expression.Convert(
Expression.Coalesce(
_entityMaterializerSource.CreateReadValueCallExpression(targetExpression, index),
Expression.Default(node.Type)),
node.Type);
}
else
{
return _entityMaterializerSource.CreateReadValueExpression(targetExpression, node.Type, index);
}
}
}
}
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