Allow components to mutate [SupplyParameterFromForm] data (#49489)

dotnet · Jul 18, 2023 · e81e73c · e81e73c
1 parent c9ac964
commit e81e73c
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Showing 11 changed files with 375 additions and 27 deletions.
diff --git a/src/Components/Components/src/CascadingParameterAttributeBase.cs b/src/Components/Components/src/CascadingParameterAttributeBase.cs
@@ -13,4 +13,10 @@ public abstract class CascadingParameterAttributeBase : Attribute
     /// of a cascading value.
     /// </summary>
     public abstract string? Name { get; set; }
+
+    /// <summary>
+    /// Gets a flag indicating whether the cascading parameter should
+    /// be supplied only once per component.
+    /// </summary>
+    internal virtual bool SingleDelivery => false;
 }
diff --git a/src/Components/Components/src/CascadingParameterState.cs b/src/Components/Components/src/CascadingParameterState.cs
@@ -25,10 +25,11 @@ public CascadingParameterState(in CascadingParameterInfo parameterInfo, ICascadi
         ValueSupplier = valueSupplier;
     }
 
-    public static IReadOnlyList<CascadingParameterState> FindCascadingParameters(ComponentState componentState)
+    public static IReadOnlyList<CascadingParameterState> FindCascadingParameters(ComponentState componentState, out bool hasSingleDeliveryParameters)
     {
         var componentType = componentState.Component.GetType();
         var infos = GetCascadingParameterInfos(componentType);
+        hasSingleDeliveryParameters = false;
 
         // For components known not to have any cascading parameters, bail out early
         if (infos.Length == 0)
@@ -50,6 +51,18 @@ public static IReadOnlyList<CascadingParameterState> FindCascadingParameters(Com
                 // Although not all parameters might be matched, we know the maximum number
                 resultStates ??= new List<CascadingParameterState>(infos.Length - infoIndex);
                 resultStates.Add(new CascadingParameterState(info, supplier));
+
+                if (info.Attribute.SingleDelivery)
+                {
+                    hasSingleDeliveryParameters = true;
+                    if (!supplier.IsFixed)
+                    {
+                        // We don't have a use case for IsFixed=false with SingleDelivery=true. To avoid complications about
+                        // subscribing/unsubscribing in this case, just disallow it. It shouldn't be possible for this to
+                        // occur unless someone creates their own CascadingParameterAttributeBase subclass.
+                        throw new InvalidOperationException($"'{info.Attribute.GetType()}' is flagged with SingleDelivery, but the selected supplier '{supplier.GetType()}' is not flagged with {nameof(ICascadingValueSupplier.IsFixed)}");
+                    }
+                }
             }
         }
 

diff --git a/src/Components/Components/src/Microsoft.AspNetCore.Components.WarningSuppressions.xml b/src/Components/Components/src/Microsoft.AspNetCore.Components.WarningSuppressions.xml
@@ -35,7 +35,7 @@
       <argument>ILLink</argument>
       <argument>IL2072</argument>
       <property name="Scope">member</property>
-      <property name="Target">M:Microsoft.AspNetCore.Components.CascadingParameterState.FindCascadingParameters(Microsoft.AspNetCore.Components.Rendering.ComponentState)</property>
+      <property name="Target">M:Microsoft.AspNetCore.Components.CascadingParameterState.FindCascadingParameters(Microsoft.AspNetCore.Components.Rendering.ComponentState,System.Boolean@)</property>
     </attribute>
     <attribute fullname="System.Diagnostics.CodeAnalysis.UnconditionalSuppressMessageAttribute">
       <argument>ILLink</argument>

diff --git a/src/Components/Components/src/Rendering/ComponentState.cs b/src/Components/Components/src/Rendering/ComponentState.cs
@@ -16,9 +16,10 @@ namespace Microsoft.AspNetCore.Components.Rendering;
 public class ComponentState : IAsyncDisposable
 {
     private readonly Renderer _renderer;
-    private readonly IReadOnlyList<CascadingParameterState> _cascadingParameters;
-    private readonly bool _hasCascadingParameters;
     private readonly bool _hasAnyCascadingParameterSubscriptions;
+    private IReadOnlyList<CascadingParameterState> _cascadingParameters;
+    private bool _hasCascadingParameters;
+    private bool _hasSingleDeliveryCascadingParameters;
     private RenderTreeBuilder _nextRenderTree;
     private ArrayBuilder<RenderTreeFrame>? _latestDirectParametersSnapshot; // Lazily instantiated
     private bool _componentWasDisposed;
@@ -39,7 +40,7 @@ public ComponentState(Renderer renderer, int componentId, IComponent component,
             ? (GetSectionOutletLogicalParent(renderer, (SectionOutlet)parentComponentState!.Component) ?? parentComponentState)
             : parentComponentState;
         _renderer = renderer ?? throw new ArgumentNullException(nameof(renderer));
-        _cascadingParameters = CascadingParameterState.FindCascadingParameters(this);
+        _cascadingParameters = CascadingParameterState.FindCascadingParameters(this, out _hasSingleDeliveryCascadingParameters);
         CurrentRenderTree = new RenderTreeBuilder();
         _nextRenderTree = new RenderTreeBuilder();
 
@@ -174,11 +175,37 @@ internal void SetDirectParameters(ParameterView parameters)
         if (_hasCascadingParameters)
         {
             parameters = parameters.WithCascadingParameters(_cascadingParameters);
+            if (_hasSingleDeliveryCascadingParameters)
+            {
+                StopSupplyingSingleDeliveryCascadingParameters();
+            }
         }
 
         SupplyCombinedParameters(parameters);
     }
 
+    private void StopSupplyingSingleDeliveryCascadingParameters()
+    {
+        // We're optimizing for the case where there are no single-delivery parameters, or if there were, we already
+        // removed them. In those cases _cascadingParameters is already up-to-date and gets used as-is without any filtering.
+        // In the unusual case were there are single-delivery parameters and we haven't yet removed them, it's OK to
+        // go through the extra work and allocation of creating a new list.
+        List<CascadingParameterState>? remainingCascadingParameters = null;
+        foreach (var param in _cascadingParameters)
+        {
+            if (!param.ParameterInfo.Attribute.SingleDelivery)
+            {
+                remainingCascadingParameters ??= new(_cascadingParameters.Count /* upper bound on capacity needed */);
+                remainingCascadingParameters.Add(param);
+            }
+        }
+
+        // Now update all the tracking state to match the filtered set
+        _hasCascadingParameters = remainingCascadingParameters is not null;
+        _cascadingParameters = (IReadOnlyList<CascadingParameterState>?)remainingCascadingParameters ?? Array.Empty<CascadingParameterState>();
+        _hasSingleDeliveryCascadingParameters = false;
+    }
+
     internal void NotifyCascadingValueChanged(in ParameterViewLifetime lifetime)
     {
         // If the component was already disposed, we must not try to supply new parameters. Among other reasons,

diff --git a/src/Components/Components/test/CascadingParameterStateTest.cs b/src/Components/Components/test/CascadingParameterStateTest.cs
@@ -16,7 +16,7 @@ public void FindCascadingParameters_IfHasNoParameters_ReturnsEmpty()
         var componentState = CreateComponentState(new ComponentWithNoParams());
 
         // Act
-        var result = CascadingParameterState.FindCascadingParameters(componentState);
+        var result = CascadingParameterState.FindCascadingParameters(componentState, out _);
 
         // Assert
         Assert.Empty(result);
@@ -29,7 +29,7 @@ public void FindCascadingParameters_IfHasNoCascadingParameters_ReturnsEmpty()
         var componentState = CreateComponentState(new ComponentWithNoCascadingParams());
 
         // Act
-        var result = CascadingParameterState.FindCascadingParameters(componentState);
+        var result = CascadingParameterState.FindCascadingParameters(componentState, out _);
 
         // Assert
         Assert.Empty(result);
@@ -42,7 +42,7 @@ public void FindCascadingParameters_IfHasNoAncestors_ReturnsEmpty()
         var componentState = CreateComponentState(new ComponentWithCascadingParams());
 
         // Act
-        var result = CascadingParameterState.FindCascadingParameters(componentState);
+        var result = CascadingParameterState.FindCascadingParameters(componentState, out _);
 
         // Assert
         Assert.Empty(result);
@@ -59,7 +59,7 @@ public void FindCascadingParameters_IfHasNoMatchesInAncestors_ReturnsEmpty()
             new ComponentWithCascadingParams());
 
         // Act
-        var result = CascadingParameterState.FindCascadingParameters(states.Last());
+        var result = CascadingParameterState.FindCascadingParameters(states.Last(), out _);
 
         // Assert
         Assert.Empty(result);
@@ -76,7 +76,7 @@ public void FindCascadingParameters_IfHasPartialMatchesInAncestors_ReturnsMatche
             new ComponentWithCascadingParams());
 
         // Act
-        var result = CascadingParameterState.FindCascadingParameters(states.Last());
+        var result = CascadingParameterState.FindCascadingParameters(states.Last(), out _);
 
         // Assert
         Assert.Collection(result, match =>
@@ -98,7 +98,7 @@ public void FindCascadingParameters_IfHasMultipleMatchesInAncestors_ReturnsMatch
             new ComponentWithCascadingParams());
 
         // Act
-        var result = CascadingParameterState.FindCascadingParameters(states.Last());
+        var result = CascadingParameterState.FindCascadingParameters(states.Last(), out _);
 
         // Assert
         Assert.Collection(result.OrderBy(x => x.ParameterInfo.PropertyName),
@@ -124,7 +124,7 @@ public void FindCascadingParameters_InheritedParameters_ReturnsMatches()
             new ComponentWithInheritedCascadingParams());
 
         // Act
-        var result = CascadingParameterState.FindCascadingParameters(states.Last());
+        var result = CascadingParameterState.FindCascadingParameters(states.Last(), out _);
 
         // Assert
         Assert.Collection(result.OrderBy(x => x.ParameterInfo.PropertyName),
@@ -149,7 +149,7 @@ public void FindCascadingParameters_ComponentRequestsBaseType_ReturnsMatches()
             new ComponentWithGenericCascadingParam<CascadingValueTypeBaseClass>());
 
         // Act
-        var result = CascadingParameterState.FindCascadingParameters(states.Last());
+        var result = CascadingParameterState.FindCascadingParameters(states.Last(), out _);
 
         // Assert
         Assert.Collection(result, match =>
@@ -168,7 +168,7 @@ public void FindCascadingParameters_ComponentRequestsImplementedInterface_Return
             new ComponentWithGenericCascadingParam<ICascadingValueTypeDerivedClassInterface>());
 
         // Act
-        var result = CascadingParameterState.FindCascadingParameters(states.Last());
+        var result = CascadingParameterState.FindCascadingParameters(states.Last(), out _);
 
         // Assert
         Assert.Collection(result, match =>
@@ -187,7 +187,7 @@ public void FindCascadingParameters_ComponentRequestsDerivedType_ReturnsEmpty()
             new ComponentWithGenericCascadingParam<CascadingValueTypeDerivedClass>());
 
         // Act
-        var result = CascadingParameterState.FindCascadingParameters(states.Last());
+        var result = CascadingParameterState.FindCascadingParameters(states.Last(), out _);
 
         // Assert
         Assert.Empty(result);
@@ -202,7 +202,7 @@ public void FindCascadingParameters_TypeAssignmentIsValidForNullValue_ReturnsMat
             new ComponentWithGenericCascadingParam<CascadingValueTypeBaseClass>());
 
         // Act
-        var result = CascadingParameterState.FindCascadingParameters(states.Last());
+        var result = CascadingParameterState.FindCascadingParameters(states.Last(), out _);
 
         // Assert
         Assert.Collection(result, match =>
@@ -221,7 +221,7 @@ public void FindCascadingParameters_TypeAssignmentIsInvalidForNullValue_ReturnsE
             new ComponentWithGenericCascadingParam<ValueType1>());
 
         // Act
-        var result = CascadingParameterState.FindCascadingParameters(states.Last());
+        var result = CascadingParameterState.FindCascadingParameters(states.Last(), out _);
 
         // Assert
         Assert.Empty(result);
@@ -236,7 +236,7 @@ public void FindCascadingParameters_SupplierSpecifiesNameButConsumerDoesNot_Retu
             new ComponentWithCascadingParams());
 
         // Act
-        var result = CascadingParameterState.FindCascadingParameters(states.Last());
+        var result = CascadingParameterState.FindCascadingParameters(states.Last(), out _);
 
         // Assert
         Assert.Empty(result);
@@ -251,7 +251,7 @@ public void FindCascadingParameters_ConsumerSpecifiesNameButSupplierDoesNot_Retu
             new ComponentWithNamedCascadingParam());
 
         // Act
-        var result = CascadingParameterState.FindCascadingParameters(states.Last());
+        var result = CascadingParameterState.FindCascadingParameters(states.Last(), out _);
 
         // Assert
         Assert.Empty(result);
@@ -266,7 +266,7 @@ public void FindCascadingParameters_MismatchingNameButMatchingType_ReturnsEmpty(
             new ComponentWithNamedCascadingParam());
 
         // Act
-        var result = CascadingParameterState.FindCascadingParameters(states.Last());
+        var result = CascadingParameterState.FindCascadingParameters(states.Last(), out _);
 
         // Assert
         Assert.Empty(result);
@@ -281,7 +281,7 @@ public void FindCascadingParameters_MatchingNameButMismatchingType_ReturnsEmpty(
             new ComponentWithNamedCascadingParam());
 
         // Act
-        var result = CascadingParameterState.FindCascadingParameters(states.Last());
+        var result = CascadingParameterState.FindCascadingParameters(states.Last(), out _);
 
         // Assert
         Assert.Empty(result);
@@ -296,7 +296,7 @@ public void FindCascadingParameters_MatchingNameAndType_ReturnsMatches()
             new ComponentWithNamedCascadingParam());
 
         // Act
-        var result = CascadingParameterState.FindCascadingParameters(states.Last());
+        var result = CascadingParameterState.FindCascadingParameters(states.Last(), out _);
 
         // Assert
         Assert.Collection(result, match =>
@@ -318,7 +318,7 @@ public void FindCascadingParameters_MultipleMatchingAncestors_ReturnsClosestMatc
             new ComponentWithCascadingParams());
 
         // Act
-        var result = CascadingParameterState.FindCascadingParameters(states.Last());
+        var result = CascadingParameterState.FindCascadingParameters(states.Last(), out _);
 
         // Assert
         Assert.Collection(result.OrderBy(x => x.ParameterInfo.PropertyName),
@@ -344,7 +344,7 @@ public void FindCascadingParameters_CanOverrideNonNullValueWithNull()
             new ComponentWithCascadingParams());
 
         // Act
-        var result = CascadingParameterState.FindCascadingParameters(states.Last());
+        var result = CascadingParameterState.FindCascadingParameters(states.Last(), out _);
 
         // Assert
         Assert.Collection(result.OrderBy(x => x.ParameterInfo.PropertyName),
@@ -356,7 +356,49 @@ public void FindCascadingParameters_CanOverrideNonNullValueWithNull()
             });
     }
 
-
+    [Fact]
+    public void FindCascadingParameters_WithoutSingleDelivery()
+    {
+        // Even though ComponentWithCascadingParams itself declares a [SupplyParameterAsSingleDelivery],
+        // none of the suppliers match it, so we'll get hasSingleDeliveryParameters = false
+
+        // Arrange
+        var states = CreateAncestry(
+            CreateCascadingValueComponent(new ValueType1()),
+            new ComponentWithCascadingParams());
+
+        // Act
+        _ = CascadingParameterState.FindCascadingParameters(states.Last(), out var hasSingleDeliveryParameters);
+
+        // Assert
+        Assert.False(hasSingleDeliveryParameters);
+    }
+
+    [Fact]
+    public void FindCascadingParameters_WithSingleDelivery()
+    {
+        // Arrange
+        var states = CreateAncestry(
+            CreateCascadingValueComponent(new ValueType1()),
+            new SupplyParameterWithSingleDeliveryComponent(isFixed: true),
+            new ComponentWithCascadingParams());
+
+        // Act
+        _ = CascadingParameterState.FindCascadingParameters(states.Last(), out var hasSingleDeliveryParameters);
+
+        // Assert
+        Assert.True(hasSingleDeliveryParameters);
+    }
+
+    [Fact]
+    public void FindCascadingParameters_DisallowsSingleDeliveryWhenIsFixedIsFalse()
+    {
+        var ex = Assert.Throws<InvalidOperationException>(() => CreateAncestry(
+            new SupplyParameterWithSingleDeliveryComponent(isFixed: false),
+            new ComponentWithCascadingParams()));
+
+        Assert.StartsWith($"'{typeof(SupplyParameterWithSingleDeliveryAttribute)}' is flagged with SingleDelivery", ex.Message);
+    }
 
     static ComponentState[] CreateAncestry(params IComponent[] components)
     {
@@ -412,6 +454,8 @@ class ComponentWithCascadingParams : TestComponentBase
         [Parameter] public bool RegularParam { get; set; }
         [CascadingParameter] internal ValueType1 CascadingParam1 { get; set; }
         [CascadingParameter] internal ValueType2 CascadingParam2 { get; set; }
+
+        [SupplyParameterWithSingleDelivery] internal ValueType3 SingleDeliveryCascadingParam { get; set; }
     }
 
     class ComponentWithInheritedCascadingParams : ComponentWithCascadingParams
@@ -430,6 +474,30 @@ class ComponentWithNamedCascadingParam : TestComponentBase
         internal ValueType1 SomeLocalName { get; set; }
     }
 
+    class SupplyParameterWithSingleDeliveryAttribute : CascadingParameterAttributeBase
+    {
+        public override string Name { get; set; }
+
+        internal override bool SingleDelivery => true;
+    }
+
+    class SupplyParameterWithSingleDeliveryComponent(bool isFixed) : ComponentBase, ICascadingValueSupplier
+    {
+        public bool IsFixed => isFixed;
+
+        public bool CanSupplyValue(in CascadingParameterInfo parameterInfo)
+            => parameterInfo.Attribute is SupplyParameterWithSingleDeliveryAttribute;
+
+        public object GetCurrentValue(in CascadingParameterInfo parameterInfo)
+            => throw new NotImplementedException();
+
+        public void Subscribe(ComponentState subscriber, in CascadingParameterInfo parameterInfo)
+            => throw new NotImplementedException();
+
+        public void Unsubscribe(ComponentState subscriber, in CascadingParameterInfo parameterInfo)
+            => throw new NotImplementedException();
+    }
+
     class TestComponentBase : IComponent
     {
         public void Attach(RenderHandle renderHandle)