public static NodeSizes Calculate(Expression node)
{
var calculator = new NodeSizeCalculator();
calculator.Visit(node);
return(new NodeSizes(totalSize: calculator.size, nodes: calculator.nodes.Values));
}
// Reduces the size of a supplied expression tree by compiling parts of the tree into individual
// delegates. Besides preventing the CLR from throwing stack overflow exceptions (which will happen
// when the tree gets somewhere between 20,000 and 50,000 nodes), this can reduce the amount of code
// that needs to be JITted and can therefore reduce the memory footprint of the application.
private static Expression ReduceObjectGraphSize(Expression expression, Container container,
Dictionary <Expression, InvocationExpression> reducedNodes = null)
{
var results = NodeSizeCalculator.Calculate(expression);
while (results.TotalSize > container.Options.MaximumNumberOfNodesPerDelegate)
{
reducedNodes = reducedNodes ?? new Dictionary <Expression, InvocationExpression>(16);
Expression mostReductiveNode = FindMostReductiveNodeOrNull(results,
container.Options.MaximumNumberOfNodesPerDelegate);
if (mostReductiveNode == null)
{
// In case mostReductiveNode is null, there's no good candidate to reduce the object
// graph. In that case we break out.
break;
}
// If the found mostReductiveNode has been reduced before, we use the previously compiled
// value (instead of doing the compilation all over again). Otherwise we compile that node.
InvocationExpression replacementNode = reducedNodes.ContainsKey(mostReductiveNode)
? reducedNodes[mostReductiveNode]
: CompileToInvocation(mostReductiveNode, container, reducedNodes);
reducedNodes[mostReductiveNode] = replacementNode;
expression = NodeReplacer.Replace(expression, oldNode: mostReductiveNode, newNode: replacementNode);
results = NodeSizeCalculator.Calculate(expression);
}
return(expression);
}
public static NodeSizes Calculate(Expression node)
{
var calculator = new NodeSizeCalculator();
calculator.Visit(node);
return(new NodeSizes {
TotalSize = calculator.size, Nodes = calculator.nodes.Values
});
}