public static void UpdateDifferentReturnsDifferent()
{
Expression bound0 = Expression.Constant(2);
Expression bound1 = Expression.Constant(3);
NewArrayExpression newArrayExpression = Expression.NewArrayBounds(typeof(string), bound0, bound1);
Assert.NotSame(newArrayExpression, newArrayExpression.Update(new[] { bound0 }));
Assert.NotSame(newArrayExpression, newArrayExpression.Update(new[] { bound0, bound1, bound0, bound1 }));
Assert.NotSame(newArrayExpression, newArrayExpression.Update(newArrayExpression.Expressions.Reverse()));
}
public static Expression Replace(ParameterExpression parameter,
Expression expr, IDictionary <string, int> variables)
{
if (expr == null)
{
return(null);
}
BinaryExpression eb = expr as BinaryExpression;
MemberExpression em = expr as MemberExpression;
UnaryExpression eu = expr as UnaryExpression;
MethodCallExpression ec = expr as MethodCallExpression;
NewArrayExpression ea = expr as NewArrayExpression;
if (em != null) // member expression
{
string varName = em.Member.Name;
int index = variables[varName];
ConstantExpression indexExpression = Expression.Constant(index);
return(Expression.ArrayAccess(parameter, indexExpression));
}
else if (eb != null) // binary expression
{
var left = Replace(parameter, eb.Left, variables);
var right = Replace(parameter, eb.Right, variables);
return(eb.Update(left, eb.Conversion, right));
}
else if (eu != null) // unary expression
{
var op = Replace(parameter, eu.Operand, variables);
return(eu.Update(op));
}
else if (ec != null) // call expression
{
List <Expression> args = new List <Expression>();
foreach (var a in ec.Arguments)
{
args.Add(Replace(parameter, a, variables));
}
return(ec.Update(ec.Object, args));
}
else if (ea != null) // new array expression
{
List <Expression> values = new List <Expression>();
foreach (var v in ea.Expressions)
{
values.Add(Replace(parameter, v, variables));
}
return(ea.Update(values));
}
else
{
return(expr);
}
}
public static void UpdateNullThrows()
{
Expression bound0 = Expression.Constant(2);
Expression bound1 = Expression.Constant(3);
NewArrayExpression newArrayExpression = Expression.NewArrayBounds(typeof(string), bound0, bound1);
AssertExtensions.Throws <ArgumentNullException>("expressions", () => newArrayExpression.Update(null));
}
public static void UpdateDoesntRepeatEnumeration()
{
Expression bound0 = Expression.Constant(2);
Expression bound1 = Expression.Constant(3);
NewArrayExpression newArrayExpression = Expression.NewArrayBounds(typeof(string), bound0, bound1);
Assert.NotSame(newArrayExpression, newArrayExpression.Update(new RunOnceEnumerable <Expression>(new[] { bound0 })));
}
public static void UpdateSameReturnsSame()
{
Expression bound0 = Expression.Constant(2);
Expression bound1 = Expression.Constant(3);
NewArrayExpression newArrayExpression = Expression.NewArrayBounds(typeof(string), bound0, bound1);
Assert.Same(newArrayExpression, newArrayExpression.Update(new [] { bound0, bound1 }));
}
/// <summary>
/// This is an internal API that supports the Entity Framework Core infrastructure and not subject to
/// the same compatibility standards as public APIs. It may be changed or removed without notice in
/// any release. You should only use it directly in your code with extreme caution and knowing that
/// doing so can result in application failures when updating to a new Entity Framework Core release.
/// </summary>
protected override Expression VisitNewArray(NewArrayExpression newArrayExpression)
{
var expressions = new Expression[newArrayExpression.Expressions.Count];
for (var i = 0; i < expressions.Length; i++)
{
expressions[i] = MatchExpressionType(
Visit(newArrayExpression.Expressions[i]),
newArrayExpression.Expressions[i].Type);
}
return(newArrayExpression.Update(expressions));
}
protected override Expression VisitNewArray(NewArrayExpression node)
{
var changed = false;
var arguments = new Expression[node.Expressions.Count];
var i = 0;
foreach (var arg in node.Expressions)
{
var argument = Visit(arg);
arguments[i] = argument;
changed |= argument != arg;
}
if (changed)
{
return(node.Update(arguments));
}
return(node);
}
protected override Expression VisitNewArray(NewArrayExpression node)
{
var visitedExpressions = Visit(node.Expressions);
if (visitedExpressions.All(e => e is ConstantExpression))
{
switch (node.NodeType)
{
case ExpressionType.NewArrayBounds:
{
return(Expression.Constant(
Array.CreateInstance(
node.Type.GetElementType(),
visitedExpressions
.Cast <ConstantExpression>()
.Select(c => c.Value)
.Cast <int>()
.ToArray())));
}
case ExpressionType.NewArrayInit:
{
var array = Array.CreateInstance(
node.Type.GetElementType(),
visitedExpressions.Count);
var values = visitedExpressions
.Cast <ConstantExpression>()
.Select((c, i) => (c.Value, i));
foreach (var(value, index) in values)
{
array.SetValue(value, index);
}
return(Expression.Constant(array));
}
}
}
return(node.Update(visitedExpressions));
}
public T?Simplify <T>(T?expression) where T : Expression
{
if (expression is null)
{
return(null);
}
Expression expr = expression.Reduce() switch
{
UnaryExpression unaryExpr => unaryExpr.Update(Simplify(unaryExpr.Operand)),
BinaryExpression binaryExpr => binaryExpr.Update(Simplify(binaryExpr.Left), binaryExpr.Conversion, Simplify(binaryExpr.Right)),
LambdaExpression lambdaExpr => Expression.Lambda(Simplify(lambdaExpr.Body), lambdaExpr.Name, lambdaExpr.TailCall, Simplify(lambdaExpr.Parameters)),
TryExpression tryExpr => tryExpr.Update(Simplify(tryExpr.Body), Simplify(tryExpr.Handlers), Simplify(tryExpr.Finally), Simplify(tryExpr.Fault)),
NewExpression newExpr => newExpr.Update(Simplify(newExpr.Arguments)),
GotoExpression gotoExpr => gotoExpr.Update(gotoExpr.Target, Simplify(gotoExpr.Value)),
LoopExpression loopExpr => loopExpr.Update(loopExpr.BreakLabel, loopExpr.ContinueLabel, Simplify(loopExpr.Body)),
BlockExpression blockExpr => blockExpr.Update(Simplify(blockExpr.Variables), Simplify(blockExpr.Expressions)),
IndexExpression indexExpr => indexExpr.Update(Simplify(indexExpr.Object) !, Simplify(indexExpr.Arguments)),
LabelExpression labelExpr => labelExpr.Update(labelExpr.Target, Simplify(labelExpr.DefaultValue)),
MemberExpression memberExpr => memberExpr.Update(Simplify(memberExpr.Expression)),
SwitchExpression switchExpr => switchExpr.Update(Simplify(switchExpr.SwitchValue), Simplify(switchExpr.Cases), Simplify(switchExpr.DefaultBody)),
DynamicExpression dynamicExpr => dynamicExpr.Update(Simplify(dynamicExpr.Arguments)),
ListInitExpression listInitExpr => listInitExpr.Update(Simplify(listInitExpr.NewExpression), Simplify(listInitExpr.Initializers)),
NewArrayExpression newArrayExpr => newArrayExpr.Update(Simplify(newArrayExpr.Expressions)),
InvocationExpression invokeExpr => invokeExpr.Update(Simplify(invokeExpr.Expression), Simplify(invokeExpr.Arguments)),
MemberInitExpression memberInitExpr => memberInitExpr.Update(Simplify(memberInitExpr.NewExpression), memberInitExpr.Bindings),
MethodCallExpression methodCallExpr => methodCallExpr.Update(Simplify(methodCallExpr.Object), Simplify(methodCallExpr.Arguments)),
TypeBinaryExpression typeBinaryExpr => typeBinaryExpr.Update(Simplify(typeBinaryExpr.Expression)),
ConditionalExpression condExpr => condExpr.Update(Simplify(condExpr.Test), Simplify(condExpr.IfTrue), Simplify(condExpr.IfFalse)),
RuntimeVariablesExpression runtimeVarExpr => runtimeVarExpr.Update(Simplify(runtimeVarExpr.Variables)),
_ => expression
};
foreach (var transform in transformers)
{
expr = transform.Transform(expr, this);
}
return((T)expr);
}
protected override Expression VisitNewArray(NewArrayExpression node)
{
var e = Visit(node.Expressions);
var args = (IList <Expression>)e;
var n = node.Expressions.Count;
if (Pop(n, out var ess) && _parent.CanEvaluate(node.Type))
{
_tilingState.Push(true);
}
else
{
_tilingState.Push(false);
EvaluateIf(ess, ref args);
}
return(node.Update(args));
}
/// <summary>
/// 访问 <see cref="NewArrayExpression"/>。
/// </summary>
/// <param name="newArrayExp">要访问的表达式。</param>
/// <returns></returns>
protected virtual Expression VisitNewArray(NewArrayExpression newArrayExp)
{
var exprs = VisitMemberAndExpressionList(newArrayExp.Expressions);
return(newArrayExp.Update(newArrayExp.Type, exprs));
}
NewArrayExpression Convert(NewArrayExpression expr)
{
return(expr.Update(Process(expr.Expressions)));
}
/// <summary>
/// Visits the children of the <see cref="NewArrayExpression" />.
/// </summary>
/// <param name="node">The expression to visit.</param>
/// <returns>The modified expression, if it or any subexpression was modified;
/// otherwise, returns the original expression.</returns>
protected internal virtual Expression VisitNewArray(NewArrayExpression node)
{
return(node.Update(Visit(node.Expressions)));
}
static NewArrayExpression MutateNewArray(NewArrayExpression node, IList <Expression> operands)
{
return(node.Update(operands));
}
protected virtual Expression VisitNewArray(NewArrayExpression expr)
{
return(expr.Update(expr.Expressions.Select(a => Visit(a))));
}
protected override Expression VisitNewArray(NewArrayExpression node)
{
var expressions = new Expression[node.Expressions.Count];
var shouldApply = true;
for (var i = 0; i < expressions.Length; i++)
{
var expression = Visit(node.Expressions[i]);
shouldApply &= expression.NodeType == ExpressionType.Constant;
expressions[i] = expression;
}
if (shouldApply)
{
try
{
switch (node.NodeType)
{
case ExpressionType.NewArrayBounds:
{
var lengths = new int[expressions.Length];
for (var i = 0; i < expressions.Length; i++)
{
lengths[i] = (int)((ConstantExpression)expressions[i]).Value;
}
return(Expression.Constant(
Array.CreateInstance(
node.Type.GetElementType(),
lengths)));
}
case ExpressionType.NewArrayInit:
{
var array
= Array.CreateInstance(
node.Type.GetElementType(),
expressions.Length);
for (var i = 0; i < expressions.Length; i++)
{
array.SetValue(((ConstantExpression)expressions[i]).Value, i);
}
return(Expression.Constant(array));
}
default:
{
throw new NotSupportedException();
}
}
}
catch
{
// no-op, proceed to update expressions
}
}
return(node.Update(expressions));
}
/// <summary>
/// Visits the children of the <see cref="NewArrayExpression"/>.
/// </summary>
/// <param name="node">The expression to visit.</param>
/// <returns>The modified expression, if it or any subexpression was modified;
/// otherwise, returns the original expression.</returns>
protected override Expression VisitNewArray(NewArrayExpression node)
{
return(node.Update(Visit(node.Expressions)));
}
protected override Expression VisitNewArray(NewArrayExpression node)
{
var exprs = VisitMemberAndExpressionList(node.Expressions);
return(node.Update(node.Type, exprs));
}
private static Expression SetChildren(ReadOnlySpan <Expression> newChildren, NewArrayExpression n) => n.Update(newChildren.ToArray());
/// <summary> /// This is an internal API that supports the Entity Framework Core infrastructure and not subject to /// the same compatibility standards as public APIs. It may be changed or removed without notice in /// any release. You should only use it directly in your code with extreme caution and knowing that /// doing so can result in application failures when updating to a new Entity Framework Core release. /// </summary> protected override Expression VisitNewArray(NewArrayExpression newArrayExpression) => newArrayExpression.Update(newArrayExpression.Expressions.Select(e => MatchTypes(Visit(e), e.Type)));
protected virtual Expression VisitNewArray(NewArrayExpression node, Type expectedType)
=> node.Update(node.NodeType == ExpressionType.NewArrayInit
? Visit(node.Expressions, node.Type)
: Visit(node.Expressions, null));