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Wrap up lifetime concept as a type, and implement expiry

This commit is contained in:
Steve Sanderson 2019-09-28 00:46:15 +01:00 committed by Artak
parent 612a6677b1
commit d59baa8a24
10 changed files with 111 additions and 41 deletions
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6
src/Components/Components/src/CascadingValue.cs
View File

@ -127,7 +127,7 @@ namespace Microsoft.AspNetCore.Components
if (_subscribers != null && ChangeDetection.MayHaveChanged(previousValue, Value))
{
NotifySubscribers();
NotifySubscribers(parameters.Lifetime);
}
return Task.CompletedTask;
@ -168,11 +168,11 @@ namespace Microsoft.AspNetCore.Components
_subscribers.Remove(subscriber);
}
private void NotifySubscribers()
private void NotifySubscribers(ParameterViewLifetime lifetime)
{
foreach (var subscriber in _subscribers)
{
subscriber.NotifyCascadingValueChanged();
subscriber.NotifyCascadingValueChanged(lifetime);
}
}

26
src/Components/Components/src/ParameterView.cs
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@ -21,24 +21,21 @@ namespace Microsoft.AspNetCore.Components
RenderTreeFrame.Element(0, string.Empty).WithComponentSubtreeLength(1)
};
private static readonly ParameterView _empty = new ParameterView(null, _emptyFrames, 0, null);
// If a value is provided for this field, then the ParameterView instance is only
// valid for as long as the lifetime owner says it is
private readonly RenderBatchBuilder _lifetimeOwner;
private static readonly ParameterView _empty = new ParameterView(ParameterViewLifetime.Unbound, _emptyFrames, 0, null);
private readonly ParameterViewLifetime _lifetime;
private readonly RenderTreeFrame[] _frames;
private readonly int _ownerIndex;
private readonly IReadOnlyList<CascadingParameterState> _cascadingParametersOrNull;
internal ParameterView(RenderBatchBuilder lifetimeOwnerOrNull, RenderTreeFrame[] frames, int ownerIndex)
: this(lifetimeOwnerOrNull, frames, ownerIndex, null)
internal ParameterView(ParameterViewLifetime lifetime, RenderTreeFrame[] frames, int ownerIndex)
: this(lifetime, frames, ownerIndex, null)
{
}
private ParameterView(RenderBatchBuilder lifetimeOwnerOrNull, RenderTreeFrame[] frames, int ownerIndex, IReadOnlyList<CascadingParameterState> cascadingParametersOrNull)
private ParameterView(ParameterViewLifetime lifetime, RenderTreeFrame[] frames, int ownerIndex, IReadOnlyList<CascadingParameterState> cascadingParametersOrNull)
{
_lifetimeOwner = lifetimeOwnerOrNull;
_lifetime = lifetime;
_frames = frames;
_ownerIndex = ownerIndex;
_cascadingParametersOrNull = cascadingParametersOrNull;
@ -49,12 +46,17 @@ namespace Microsoft.AspNetCore.Components
/// </summary>
public static ParameterView Empty => _empty;
internal ParameterViewLifetime Lifetime => _lifetime;
/// <summary>
/// Returns an enumerator that iterates through the <see cref="ParameterView"/>.
/// </summary>
/// <returns>The enumerator.</returns>
public Enumerator GetEnumerator()
=> new Enumerator(_frames, _ownerIndex, _cascadingParametersOrNull);
{
_lifetime.AssertNotExpired();
return new Enumerator(_frames, _ownerIndex, _cascadingParametersOrNull);
}
/// <summary>
/// Gets the value of the parameter with the specified name.
@ -114,7 +116,7 @@ namespace Microsoft.AspNetCore.Components
}
internal ParameterView WithCascadingParameters(IReadOnlyList<CascadingParameterState> cascadingParameters)
=> new ParameterView(_lifetimeOwner, _frames, _ownerIndex, cascadingParameters);
=> new ParameterView(_lifetime, _frames, _ownerIndex, cascadingParameters);
// It's internal because there isn't a known use case for user code comparing
// ParameterView instances, and even if there was, it's unlikely it should
@ -221,7 +223,7 @@ namespace Microsoft.AspNetCore.Components
frames[++i] = RenderTreeFrame.Attribute(i, kvp.Key, kvp.Value);
}
return new ParameterView(null, frames, 0);
return new ParameterView(ParameterViewLifetime.Unbound, frames, 0);
}
/// <summary>

8
src/Components/Components/src/RenderTree/RenderTreeDiffBuilder.cs
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@ -519,8 +519,9 @@ namespace Microsoft.AspNetCore.Components.RenderTree
// comparisons it wants with the old values. Later we could choose to pass the
// old parameter values if we wanted. By default, components always rerender
// after any SetParameters call, which is safe but now always optimal for perf.
var oldParameters = new ParameterView(null, oldTree, oldComponentIndex);
var newParameters = new ParameterView(diffContext.BatchBuilder, newTree, newComponentIndex);
var oldParameters = new ParameterView(ParameterViewLifetime.Unbound, oldTree, oldComponentIndex);
var newParametersLifetime = new ParameterViewLifetime(diffContext.BatchBuilder);
var newParameters = new ParameterView(newParametersLifetime, newTree, newComponentIndex);
if (!newParameters.DefinitelyEquals(oldParameters))
{
componentState.SetDirectParameters(newParameters);
@ -893,7 +894,8 @@ namespace Microsoft.AspNetCore.Components.RenderTree
var childComponentState = frame.ComponentState;
// Set initial parameters
var initialParameters = new ParameterView(diffContext.BatchBuilder, frames, frameIndex);
var initialParametersLifetime = new ParameterViewLifetime(diffContext.BatchBuilder);
var initialParameters = new ParameterView(initialParametersLifetime, frames, frameIndex);
childComponentState.SetDirectParameters(initialParameters);
}

5
src/Components/Components/src/Rendering/ComponentState.cs
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@ -73,6 +73,7 @@ namespace Microsoft.AspNetCore.Components.Rendering
_renderTreeBuilderPrevious.GetFrames(),
CurrentRenderTree.GetFrames());
batchBuilder.UpdatedComponentDiffs.Append(diff);
batchBuilder.InvalidateParameterViews();
}
public bool TryDisposeInBatch(RenderBatchBuilder batchBuilder, out Exception exception)
@ -156,10 +157,10 @@ namespace Microsoft.AspNetCore.Components.Rendering
_renderer.AddToPendingTasks(Component.SetParametersAsync(parameters));
}
public void NotifyCascadingValueChanged()
public void NotifyCascadingValueChanged(ParameterViewLifetime lifetime)
{
var directParams = _latestDirectParametersSnapshot != null
? new ParameterView(null, _latestDirectParametersSnapshot.Buffer, 0)
? new ParameterView(lifetime, _latestDirectParametersSnapshot.Buffer, 0)
: ParameterView.Empty;
var allParams = directParams.WithCascadingParameters(_cascadingParameters);
var task = Component.SetParametersAsync(allParams);

30
src/Components/Components/src/Rendering/ParameterViewLifetime.cs Normal file
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@ -0,0 +1,30 @@
// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
using System;
namespace Microsoft.AspNetCore.Components.Rendering
{
internal readonly struct ParameterViewLifetime
{
private readonly RenderBatchBuilder _owner;
private readonly int _stamp;
public static readonly ParameterViewLifetime Unbound = default;
public ParameterViewLifetime(RenderBatchBuilder owner)
{
_owner = owner;
_stamp = owner.ParameterViewValidityStamp;
}
public void AssertNotExpired()
{
// _owner will be null if this instance is default(ParameterViewLifetime)
if (_owner != null && _owner.ParameterViewValidityStamp != _stamp)
{
throw new InvalidOperationException($"The {nameof(ParameterView)} instance can no longer be read because it has expired. {nameof(ParameterView)} can only be read synchronously and must not be stored for later use.");
}
}
}
}

24
src/Components/Components/src/Rendering/RenderBatchBuilder.cs
View File

@ -3,6 +3,7 @@
using System;
using System.Collections.Generic;
using System.Threading;
using Microsoft.AspNetCore.Components.RenderTree;
namespace Microsoft.AspNetCore.Components.Rendering
@ -15,6 +16,11 @@ namespace Microsoft.AspNetCore.Components.Rendering
/// </summary>
internal class RenderBatchBuilder : IDisposable
{
// A value that, if changed, causes expiry of all ParameterView instances issued
// for this RenderBatchBuilder. This is to prevent invalid reads from arrays that
// may have been returned to the shared pool.
private int _parameterViewValidityStamp;
// Primary result data
public ArrayBuilder<RenderTreeDiff> UpdatedComponentDiffs { get; } = new ArrayBuilder<RenderTreeDiff>();
public ArrayBuilder<int> DisposedComponentIds { get; } = new ArrayBuilder<int>();
@ -31,6 +37,8 @@ namespace Microsoft.AspNetCore.Components.Rendering
// Scratch data structure for understanding attribute diffs.
public Dictionary<string, int> AttributeDiffSet { get; } = new Dictionary<string, int>();
public int ParameterViewValidityStamp => _parameterViewValidityStamp;
internal StackObjectPool<Dictionary<object, KeyedItemInfo>> KeyedItemInfoDictionaryPool { get; }
= new StackObjectPool<Dictionary<object, KeyedItemInfo>>(maxPreservedItems: 10, () => new Dictionary<object, KeyedItemInfo>());
@ -58,6 +66,22 @@ namespace Microsoft.AspNetCore.Components.Rendering
DisposedComponentIds.ToRange(),
DisposedEventHandlerIds.ToRange());
public void InvalidateParameterViews()
{
// Wrapping is fine because all that matters is whether a snapshotted value matches
// the current one. There's no plausible case where it wraps around and happens to
// increment all the way back to a previously-snapshotted value on the exact same
// call that's checking the value.
if (_parameterViewValidityStamp == int.MaxValue)
{
_parameterViewValidityStamp = int.MinValue;
}
else
{
_parameterViewValidityStamp++;
}
}
public void Dispose()
{
EditsBuffer.Dispose();

2
src/Components/Components/test/CascadingParameterTest.cs
View File

@ -385,7 +385,7 @@ namespace Microsoft.AspNetCore.Components.Test
// It's no longer able to access anything in the ParameterView it just received
var ex = Assert.Throws<InvalidOperationException>(nestedComponent.AttemptIllegalAccessToLastParameterView);
Assert.Equal("blah", ex.Message);
Assert.Equal($"The {nameof(ParameterView)} instance can no longer be read because it has expired. {nameof(ParameterView)} can only be read synchronously and must not be stored for later use.", ex.Message);
}
private static T FindComponent<T>(CapturedBatch batch, out int componentId)

2
src/Components/Components/test/ParameterViewTest.Assignment.cs
View File

@ -673,7 +673,7 @@ namespace Microsoft.AspNetCore.Components
}
builder.CloseComponent();
var view = new ParameterView(null, builder.GetFrames().Array, ownerIndex: 0);
var view = new ParameterView(ParameterViewLifetime.Unbound, builder.GetFrames().Array, ownerIndex: 0);
var cascadingParameters = new List<CascadingParameterState>();
foreach (var kvp in _keyValuePairs)

28
src/Components/Components/test/ParameterViewTest.cs
View File

@ -20,7 +20,7 @@ namespace Microsoft.AspNetCore.Components
{
RenderTreeFrame.ChildComponent(0, typeof(FakeComponent)).WithComponentSubtreeLength(1)
};
var parameters = new ParameterView(null, frames, 0);
var parameters = new ParameterView(ParameterViewLifetime.Unbound, frames, 0);
// Assert
Assert.Empty(ToEnumerable(parameters));
@ -34,7 +34,7 @@ namespace Microsoft.AspNetCore.Components
{
RenderTreeFrame.Element(0, "some element").WithElementSubtreeLength(1)
};
var parameters = new ParameterView(null, frames, 0);
var parameters = new ParameterView(ParameterViewLifetime.Unbound, frames, 0);
// Assert
Assert.Empty(ToEnumerable(parameters));
@ -56,7 +56,7 @@ namespace Microsoft.AspNetCore.Components
// end of the owner's descendants
RenderTreeFrame.Attribute(3, "orphaned attribute", "value")
};
var parameters = new ParameterView(null, frames, 0);
var parameters = new ParameterView(ParameterViewLifetime.Unbound, frames, 0);
// Assert
Assert.Collection(ToEnumerable(parameters),
@ -78,7 +78,7 @@ namespace Microsoft.AspNetCore.Components
RenderTreeFrame.Element(3, "child element").WithElementSubtreeLength(2),
RenderTreeFrame.Attribute(4, "child attribute", "some value")
};
var parameters = new ParameterView(null, frames, 0);
var parameters = new ParameterView(ParameterViewLifetime.Unbound, frames, 0);
// Assert
Assert.Collection(ToEnumerable(parameters),
@ -93,7 +93,7 @@ namespace Microsoft.AspNetCore.Components
var attribute1Value = new object();
var attribute2Value = new object();
var attribute3Value = new object();
var parameters = new ParameterView(null, new[]
var parameters = new ParameterView(ParameterViewLifetime.Unbound, new[]
{
RenderTreeFrame.Element(0, "some element").WithElementSubtreeLength(2),
RenderTreeFrame.Attribute(1, "attribute 1", attribute1Value)
@ -114,7 +114,7 @@ namespace Microsoft.AspNetCore.Components
public void CanTryGetNonExistingValue()
{
// Arrange
var parameters = new ParameterView(null, new[]
var parameters = new ParameterView(ParameterViewLifetime.Unbound, new[]
{
RenderTreeFrame.Element(0, "some element").WithElementSubtreeLength(2),
RenderTreeFrame.Attribute(1, "some other entry", new object())
@ -132,7 +132,7 @@ namespace Microsoft.AspNetCore.Components
public void CanTryGetExistingValueWithCorrectType()
{
// Arrange
var parameters = new ParameterView(null, new[]
var parameters = new ParameterView(ParameterViewLifetime.Unbound, new[]
{
RenderTreeFrame.Element(0, "some element").WithElementSubtreeLength(2),
RenderTreeFrame.Attribute(1, "my entry", "hello")
@ -151,7 +151,7 @@ namespace Microsoft.AspNetCore.Components
{
// Arrange
var myEntryValue = new object();
var parameters = new ParameterView(null, new[]
var parameters = new ParameterView(ParameterViewLifetime.Unbound, new[]
{
RenderTreeFrame.Element(0, "some element").WithElementSubtreeLength(2),
RenderTreeFrame.Attribute(1, "my entry", myEntryValue),
@ -170,7 +170,7 @@ namespace Microsoft.AspNetCore.Components
{
// Arrange
var myEntryValue = new object();
var parameters = new ParameterView(null, new[]
var parameters = new ParameterView(ParameterViewLifetime.Unbound, new[]
{
RenderTreeFrame.Element(0, "some element").WithElementSubtreeLength(3),
RenderTreeFrame.Attribute(1, "my entry", myEntryValue),
@ -188,7 +188,7 @@ namespace Microsoft.AspNetCore.Components
public void CanGetValueOrDefault_WithNonExistingValue()
{
// Arrange
var parameters = new ParameterView(null, new[]
var parameters = new ParameterView(ParameterViewLifetime.Unbound, new[]
{
RenderTreeFrame.Element(0, "some element").WithElementSubtreeLength(2),
RenderTreeFrame.Attribute(1, "some other entry", new object())
@ -209,7 +209,7 @@ namespace Microsoft.AspNetCore.Components
{
// Arrange
var explicitDefaultValue = new DateTime(2018, 3, 20);
var parameters = new ParameterView(null, new[]
var parameters = new ParameterView(ParameterViewLifetime.Unbound, new[]
{
RenderTreeFrame.Element(0, "some element").WithElementSubtreeLength(2),
RenderTreeFrame.Attribute(1, "some other entry", new object())
@ -226,7 +226,7 @@ namespace Microsoft.AspNetCore.Components
public void ThrowsIfTryGetExistingValueWithIncorrectType()
{
// Arrange
var parameters = new ParameterView(null, new[]
var parameters = new ParameterView(ParameterViewLifetime.Unbound, new[]
{
RenderTreeFrame.Element(0, "some element").WithElementSubtreeLength(2),
RenderTreeFrame.Attribute(1, "my entry", "hello")
@ -275,7 +275,7 @@ namespace Microsoft.AspNetCore.Components
{
// Arrange
var entry2Value = new object();
var parameters = new ParameterView(null, new[]
var parameters = new ParameterView(ParameterViewLifetime.Unbound, new[]
{
RenderTreeFrame.Element(0, "some element").WithElementSubtreeLength(3),
RenderTreeFrame.Attribute(0, "entry 1", "value 1"),
@ -304,7 +304,7 @@ namespace Microsoft.AspNetCore.Components
{
// Arrange
var myEntryValue = new object();
var parameters = new ParameterView(null, new[]
var parameters = new ParameterView(ParameterViewLifetime.Unbound, new[]
{
RenderTreeFrame.Element(0, "some element").WithElementSubtreeLength(2),
RenderTreeFrame.Attribute(1, "unrelated value", new object())

21
src/Components/Components/test/RendererTest.cs
View File

@ -3706,17 +3706,26 @@ namespace Microsoft.AspNetCore.Components.Test
{
// Arrange
var renderer = new TestRenderer();
var component = new ParameterViewIllegalCapturingComponent();
var componentId = renderer.AssignRootComponentId(component);
renderer.RenderRootComponentAsync(componentId);
var rootComponent = new TestComponent(builder =>
{
builder.OpenComponent<ParameterViewIllegalCapturingComponent>(0);
builder.AddAttribute(1, nameof(ParameterViewIllegalCapturingComponent.SomeParam), 0);
builder.CloseComponent();
});
var rootComponentId = renderer.AssignRootComponentId(rootComponent);
// Note that we're not waiting for the async render to complete, since we want to assert
// about the situation immediately after the component yields the thread
renderer.RenderRootComponentAsync(rootComponentId);
// Act/Assert
var capturingComponent = (ParameterViewIllegalCapturingComponent)renderer.GetCurrentRenderTreeFrames(rootComponentId).Array[0].Component;
var ex = Assert.Throws<InvalidOperationException>(() =>
{
// TODO: check other types of access too
component.CapturedParameterView.TryGetValue<object>("anything", out _);
capturingComponent.CapturedParameterView.TryGetValue<object>("anything", out _);
});
Assert.Equal("blah", ex.Message);
Assert.Equal($"The {nameof(ParameterView)} instance can no longer be read because it has expired. {nameof(ParameterView)} can only be read synchronously and must not be stored for later use.", ex.Message);
}
private class NoOpRenderer : Renderer
@ -4466,6 +4475,8 @@ namespace Microsoft.AspNetCore.Components.Test
{
public ParameterView CapturedParameterView { get; private set; }
[Parameter] public int SomeParam { get; set; }
public void Attach(RenderHandle renderHandle)
{
}