private Expression ParameterizeQuery(Expression expression, QueryProcessingContext context)
{
// Parameterize the expression by substituting any ConstantExpression
// that is not a literal constant (such as a closure instance) with a ParameterExpression.
return(new ConstantParameterizingExpressionVisitor(context.ParameterMapping).Visit(expression));
}
private Func <object[], object> CompileDelegate(Expression expression, QueryProcessingContext context)
{
var parameters = new ParameterExpression[context.ParameterMapping.Count + 1];
parameters[0] = context.ExecutionContextParameter;
context.ParameterMapping.Values.CopyTo(parameters, 1);
var parameterArray = Expression.Parameter(typeof(object[]));
// Wrap the actual lambda in a static invocation.
// This is faster than just compiling it and calling DynamicInvoke.
return(Expression
.Lambda <Func <object[], object> >(
Expression.Convert(
Expression.Invoke(
Expression.Lambda(expression, parameters),
parameters.Select((p, i) =>
Expression.Convert(
Expression.ArrayIndex(
parameterArray,
Expression.Constant(i)),
p.Type))),
typeof(object)),
parameterArray)
.Compile());
}
private Expression InlineQuery(Expression expression, QueryProcessingContext context)
{
// Partially evaluate the expression. In addition to reducing evaluable nodes such
// as `new DateTime(2000, 01, 01)` down to ConstantExpressions, this visitor also expands
// IQueryable-producing expressions such as those found within calls to SelectMany
// so that the resulting IQueryable's expression tree will be integrated into the
// current expression tree.
return(queryableInliningExpressionVisitorFactory.Create(context).Visit(expression));
}
public virtual IEnumerable <ExpressionVisitor> CreateExpressionVisitors(QueryProcessingContext context)
{
yield return(new QueryCompilingExpressionVisitor(
translatabilityAnalyzingExpressionVisitor,
queryTranslatingExpressionVisitorFactory,
new MaterializerGeneratingExpressionVisitor(
translatabilityAnalyzingExpressionVisitor,
readValueExpressionFactoryProvider),
context.ExecutionContextParameter));
}
public IEnumerable <ExpressionVisitor> CreateExpressionVisitors(QueryProcessingContext context)
{
yield return(new ConditionalComparisonOptimizingExpressionVisitor());
yield return(new SelectorPushdownExpressionVisitor());
yield return(new RedundantConversionStrippingExpressionVisitor());
yield return(new NullOrDefaultEqualityOptimizingExpressionVisitor());
yield return(new BooleanOptimizingExpressionVisitor());
}
public virtual IEnumerable <ExpressionVisitor> CreateExpressionVisitors(QueryProcessingContext context)
{
yield return(new KeyEqualityComposingExpressionVisitor(context.DescriptorSet));
yield return(new NavigationComposingExpressionVisitor(context.DescriptorSet.NavigationDescriptors));
yield return(new TableAliasComposingExpressionVisitor());
yield return(new QueryComposingExpressionVisitor(
translatabilityAnalyzingExpressionVisitor,
rewritingExpressionVisitorProvider.CreateExpressionVisitors(context),
new SqlParameterRewritingExpressionVisitor(context.ParameterMapping.Values)));
}
public virtual IEnumerable <ExpressionVisitor> CreateExpressionVisitors(QueryProcessingContext context)
{
yield return(new SqlServerObjectToStringRewritingExpressionVisitor());
yield return(new SqlServerStringToNumberAsciiRewritingExpressionVisitor());
yield return(new SqlServerCountRewritingExpressionVisitor());
yield return(new SqlServerMathMethodRewritingExpressionVisitor());
yield return(new SqlServerJsonMemberRewritingExpressionVisitor());
yield return(new SqlServerStringJoinRewritingExpressionVisitor(context));
}
private Expression ApplyVisitors(Expression expression, QueryProcessingContext context)
{
var composingExpressionVisitors
= composingExpressionVisitorProvider
.CreateExpressionVisitors(context)
.ToArray();
var optimizingExpressionVisitors
= optimizingExpressionVisitorProvider
.CreateExpressionVisitors(context)
.ToArray();
var compilingExpressionVisitors
= compilingExpressionVisitorProvider
.CreateExpressionVisitors(context)
.ToArray();
// Apply all optimizing visitors before each composing visitor and then apply all
// optimizing visitors one last time.
foreach (var optimizingVisitor in optimizingExpressionVisitors)
{
expression = optimizingVisitor.Visit(expression);
}
foreach (var composingVisitor in composingExpressionVisitors)
{
expression = composingVisitor.Visit(expression);
foreach (var optimizingVisitor in optimizingExpressionVisitors)
{
expression = optimizingVisitor.Visit(expression);
}
}
// Transform the expression by rewriting all composed query expressions into
// executable expressions that make database calls and perform result materialization.
foreach (var compilingVisitor in compilingExpressionVisitors)
{
expression = compilingVisitor.Visit(expression);
}
return(expression);
}
public virtual IEnumerable <ExpressionVisitor> CreateExpressionVisitors(QueryProcessingContext context)
{
/*
*
* Order-dependency notes:
*
* - ListContainsToEnumerableContainsRewritingExpressionVisitor
* - has to run before EnumerableContainsRewritingExpressionVisitor
*
* - GroupingAggregationRewritingExpressionVisitor
* - has to run before the QueryComposingExpressionVisitor recurses
*
* - SqlServerStringJoinRewritingExpressionVisitor
* - has to run after the QueryComposingExpressionVisitor recurses
*
* Ideally none of these would be order-dependent beyond running before
* or after the QueryComposingExpressionVisitor recurses.
*
*/
yield return(new ListContainsToEnumerableContainsRewritingExpressionVisitor());
yield return(new EqualsMethodRewritingExpressionVisitor());
yield return(new KeyEqualityRewritingExpressionVisitor(context.DescriptorSet));
yield return(new GroupingAggregationRewritingExpressionVisitor(translatabilityAnalyzingExpressionVisitor));
yield return(new TypeBinaryExpressionRewritingExpressionVisitor());
yield return(new NullableMemberRewritingExpressionVisitor());
yield return(new DateTimeMemberRewritingExpressionVisitor());
yield return(new StringMemberRewritingExpressionVisitor());
yield return(new CollectionContainsRewritingExpressionVisitor());
yield return(new EnumerableContainsRewritingExpressionVisitor());
yield return(new EnumerableQueryEqualityRewritingExpressionVisitor());
yield return(new EnumHasFlagRewritingExpressionVisitor(typeMappingProvider));
}
public virtual IEnumerable <ExpressionVisitor> CreateExpressionVisitors(QueryProcessingContext context)
{
// 'Simple' replacement rewriters
yield return(new ListContainsToEnumerableContainsRewritingExpressionVisitor());
yield return(new EqualsMethodRewritingExpressionVisitor());
// 'Core' rewriters
yield return(new KeyEqualityRewritingExpressionVisitor(context.DescriptorSet));
yield return(new GroupingAggregationRewritingExpressionVisitor(translatabilityAnalyzingExpressionVisitor));
yield return(new TypeBinaryExpressionRewritingExpressionVisitor());
yield return(new NullableMemberRewritingExpressionVisitor());
yield return(new DateTimeMemberRewritingExpressionVisitor());
yield return(new StringMemberRewritingExpressionVisitor());
yield return(new CollectionContainsRewritingExpressionVisitor());
yield return(new EnumerableContainsRewritingExpressionVisitor());
yield return(new EnumerableQueryEqualityRewritingExpressionVisitor());
// SQL Server specific rewriters (should be pulled from the default provider at some point)
yield return(new ObjectToStringRewritingExpressionVisitor());
yield return(new StringToNumberAsciiRewritingExpressionVisitor());
yield return(new SqlServerCountRewritingExpressionVisitor());
yield return(new SqlServerMathMethodRewritingExpressionVisitor());
yield return(new SqlServerJsonMemberRewritingExpressionVisitor());
}
private int ComputeHash(Expression expression, QueryProcessingContext context)
{
// Generate a hash code for the parameterized expression.
// Because the expression is parameterized, the hash code will be identical
// for expressions that are structurally equivalent apart from any closure instances.
var comparer = ExpressionEqualityComparer.Instance;
var hash = comparer.GetHashCode(expression);
// Some parameters may have been eliminated during query inlining,
// so we need to make sure all of our parameters' types are included
// in the hash code to avoid errors related to mismatched closure types.
unchecked
{
foreach (var parameter in context.ParameterMapping.Values)
{
hash = (hash * 16777619) ^ comparer.GetHashCode(parameter);
}
}
return(hash);
}
public QueryableInliningExpressionVisitor Create(QueryProcessingContext context)
{
return(new QueryableInliningExpressionVisitor(context.QueryProvider, context.ParameterMapping));
}
