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Merged
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Apr 27, 2019
Merged

Avoid allocations in more cases #9788

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ee19ee1
Avoid allocations in more cases
Apr 26, 2019
510fa81
lol
Apr 26, 2019
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4 changes: 2 additions & 2 deletions src/Http/HttpAbstractions.sln
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Original file line number Diff line number Diff line change
Expand Up @@ -113,7 +113,7 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Microsoft.AspNetCore.HttpOv
EndProject
Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Microsoft.AspNetCore.Server.IISIntegration", "..\Servers\IIS\IISIntegration\src\Microsoft.AspNetCore.Server.IISIntegration.csproj", "{1062FCDE-E145-40EC-B175-FDBCAA0C59A0}"
EndProject
Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Microsoft.AspNetCore.WebUtilities.Performance", "WebUtilities\perf\Microsoft.AspNetCore.WebUtilities.Performance\Microsoft.AspNetCore.WebUtilities.Performance.csproj", "{21AC56E7-4E77-4B0E-B63E-C8E836E4D14E}"
Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Microsoft.AspNetCore.WebUtilities.Performance", "WebUtilities\perf\Microsoft.AspNetCore.WebUtilities.Performance\Microsoft.AspNetCore.WebUtilities.Performance.csproj", "{21AC56E7-4E77-4B0E-B63E-C8E836E4D14E}"
EndProject
Global
GlobalSection(SolutionConfigurationPlatforms) = preSolution
Expand Down Expand Up @@ -642,7 +642,7 @@ Global
{1A866315-5FD5-4F96-BFAC-1447E3CB4514} = {80A090C8-ED02-4DE3-875A-30DCCDBD84BA}
{068A1DA0-C7DF-4E3C-9933-4E79A141EFF8} = {80A090C8-ED02-4DE3-875A-30DCCDBD84BA}
{8C635944-51F0-4BB0-A89E-CA49A7D9BE7F} = {FB2DCA0F-EB9E-425B-ABBC-D543DBEC090F}
{1A74D674-5D19-4575-B443-8B7ED433EF2B} = {793FFE24-138A-4C3D-81AB-18D625E36230}
{1A74D674-5D19-4575-B443-8B7ED433EF2B} = {14A7B3DE-46C8-4245-B0BD-9AFF3795C163}
{B8812D83-0F76-48F4-B716-C7356DB51E72} = {14A7B3DE-46C8-4245-B0BD-9AFF3795C163}
{215E7408-A123-4B5F-B625-59ED22031109} = {DC519C5E-CA6E-48CA-BF35-B46305B83013}
{8B64326C-A87F-4157-8337-22B5C4D7A4B7} = {DC519C5E-CA6E-48CA-BF35-B46305B83013}
Expand Down
58 changes: 37 additions & 21 deletions src/Http/Routing/src/Matching/CandidateSet.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -20,9 +20,7 @@ namespace Microsoft.AspNetCore.Routing.Matching
/// </summary>
public sealed class CandidateSet
{
private const int BitVectorSize = 32;

private CandidateState[] _candidates;
internal CandidateState[] Candidates;

/// <summary>
/// <para>
Expand Down Expand Up @@ -59,26 +57,32 @@ public CandidateSet(Endpoint[] endpoints, RouteValueDictionary[] values, int[] s
throw new ArgumentException($"The provided {nameof(endpoints)}, {nameof(values)}, and {nameof(scores)} must have the same length.");
}

_candidates = new CandidateState[endpoints.Length];
Candidates = new CandidateState[endpoints.Length];
for (var i = 0; i < endpoints.Length; i++)
{
_candidates[i] = new CandidateState(endpoints[i], values[i], scores[i]);
Candidates[i] = new CandidateState(endpoints[i], values[i], scores[i]);
}
}

// Used in tests.
internal CandidateSet(Candidate[] candidates)
{
_candidates = new CandidateState[candidates.Length];
Candidates = new CandidateState[candidates.Length];
for (var i = 0; i < candidates.Length; i++)
{
_candidates[i] = new CandidateState(candidates[i].Endpoint, candidates[i].Score);
Candidates[i] = new CandidateState(candidates[i].Endpoint, candidates[i].Score);
}
}

internal CandidateSet(CandidateState[] candidates)
{
Candidates = candidates;
}

/// <summary>
/// Gets the count of candidates in the set.
/// </summary>
public int Count => _candidates.Length;
public int Count => Candidates.Length;

/// <summary>
/// Gets the <see cref="CandidateState"/> associated with the candidate <see cref="Endpoint"/>
Expand All @@ -103,7 +107,7 @@ public ref CandidateState this[int index]
ThrowIndexArgumentOutOfRangeException();
}

return ref _candidates[index];
return ref Candidates[index];
}
}

Expand All @@ -124,7 +128,12 @@ public bool IsValidCandidate(int index)
ThrowIndexArgumentOutOfRangeException();
}

return _candidates[index].Score >= 0;
return IsValidCandidate(ref Candidates[index]);
}

internal static bool IsValidCandidate(ref CandidateState candidate)
{
return candidate.Score >= 0;
}

/// <summary>
Expand All @@ -142,8 +151,15 @@ public void SetValidity(int index, bool value)
ThrowIndexArgumentOutOfRangeException();
}

ref var original = ref _candidates[index];
_candidates[index] = new CandidateState(original.Endpoint, original.Values, original.Score >= 0 ^ value ? ~original.Score : original.Score);
ref var original = ref Candidates[index];
SetValidity(ref original, value);
}

internal static void SetValidity(ref CandidateState candidate, bool value)
{
var originalScore = candidate.Score;
var score = originalScore >= 0 ^ value ? ~originalScore : originalScore;
candidate = new CandidateState(candidate.Endpoint, candidate.Values, score);
}

/// <summary>
Expand All @@ -168,7 +184,7 @@ public void ReplaceEndpoint(int index, Endpoint endpoint, RouteValueDictionary v
ThrowIndexArgumentOutOfRangeException();
}

_candidates[index] = new CandidateState(endpoint, values, _candidates[index].Score);
Candidates[index] = new CandidateState(endpoint, values, Candidates[index].Score);

if (endpoint == null)
{
Expand Down Expand Up @@ -229,18 +245,18 @@ public void ExpandEndpoint(int index, IReadOnlyList<Endpoint> endpoints, ICompar
break;

case 1:
ReplaceEndpoint(index, endpoints[0], _candidates[index].Values);
ReplaceEndpoint(index, endpoints[0], Candidates[index].Values);
break;

default:

var score = GetOriginalScore(index);
var values = _candidates[index].Values;
var values = Candidates[index].Values;

// Adding candidates requires expanding the array and computing new score values for the new candidates.
var original = _candidates;
var original = Candidates;
var candidates = new CandidateState[original.Length - 1 + endpoints.Count];
_candidates = candidates;
Candidates = candidates;

// Since the new endpoints have an unknown ordering relationship to each other, we need to:
// - order them
Expand Down Expand Up @@ -293,12 +309,12 @@ public void ExpandEndpoint(int index, IReadOnlyList<Endpoint> endpoints, ICompar
scoreOffset++;
}

_candidates[i + index] = new CandidateState(buffer[i], values, score + scoreOffset);
Candidates[i + index] = new CandidateState(buffer[i], values, score + scoreOffset);
}

for (var i = index + 1; i < original.Length; i++)
{
_candidates[i + endpoints.Count - 1] = new CandidateState(original[i].Endpoint, original[i].Values, original[i].Score + scoreOffset);
Candidates[i + endpoints.Count - 1] = new CandidateState(original[i].Endpoint, original[i].Values, original[i].Score + scoreOffset);
}

break;
Expand All @@ -311,7 +327,7 @@ public void ExpandEndpoint(int index, IReadOnlyList<Endpoint> endpoints, ICompar
// This is the original score and used to determine if there are ambiguities.
private int GetOriginalScore(int index)
{
var score = _candidates[index].Score;
var score = Candidates[index].Score;
return score >= 0 ? score : ~score;
}

Expand All @@ -320,7 +336,7 @@ private void ValidateUniqueScore(int index)
var score = GetOriginalScore(index);

var count = 0;
var candidates = _candidates;
var candidates = Candidates;
for (var i = 0; i < candidates.Length; i++)
{
if (GetOriginalScore(i) == score)
Expand Down
40 changes: 24 additions & 16 deletions src/Http/Routing/src/Matching/DefaultEndpointSelector.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -9,7 +9,7 @@

namespace Microsoft.AspNetCore.Routing.Matching
{
internal class DefaultEndpointSelector : EndpointSelector
internal sealed class DefaultEndpointSelector : EndpointSelector
{
public override Task SelectAsync(
HttpContext httpContext,
Expand All @@ -31,9 +31,18 @@ public override Task SelectAsync(
throw new ArgumentNullException(nameof(candidateSet));
}

Select(httpContext, context, candidateSet.Candidates);
return Task.CompletedTask;
}

internal static void Select(
HttpContext httpContext,
EndpointSelectorContext context,
CandidateState[] candidateState)
{
// Fast path: We can specialize for trivial numbers of candidates since there can
// be no ambiguities
switch (candidateSet.Count)
switch (candidateState.Length)
{
case 0:
{
Expand All @@ -43,9 +52,9 @@ public override Task SelectAsync(

case 1:
{
if (candidateSet.IsValidCandidate(0))
ref var state = ref candidateState[0];
if (CandidateSet.IsValidCandidate(ref state))
{
ref var state = ref candidateSet[0];
context.Endpoint = state.Endpoint;
context.RouteValues = state.Values;
}
Expand All @@ -57,30 +66,28 @@ public override Task SelectAsync(
{
// Slow path: There's more than one candidate (to say nothing of validity) so we
// have to process for ambiguities.
ProcessFinalCandidates(httpContext, context, candidateSet);
ProcessFinalCandidates(httpContext, context, candidateState);
break;
}
}

return Task.CompletedTask;
}

private static void ProcessFinalCandidates(
HttpContext httpContext,
EndpointSelectorContext context,
CandidateSet candidateSet)
CandidateState[] candidateState)
{
Endpoint endpoint = null;
RouteValueDictionary values = null;
int? foundScore = null;
for (var i = 0; i < candidateSet.Count; i++)
for (var i = 0; i < candidateState.Length; i++)
{
if (!candidateSet.IsValidCandidate(i))
ref var state = ref candidateState[i];
if (!CandidateSet.IsValidCandidate(ref state))
{
continue;
}

ref var state = ref candidateSet[i];
if (foundScore == null)
{
// This is the first match we've seen - speculatively assign it.
Expand All @@ -103,7 +110,7 @@ private static void ProcessFinalCandidates(
//
// Don't worry about the 'null == state.Score' case, it returns false.

ReportAmbiguity(candidateSet);
ReportAmbiguity(candidateState);

// Unreachable, ReportAmbiguity always throws.
throw new NotSupportedException();
Expand All @@ -117,16 +124,17 @@ private static void ProcessFinalCandidates(
}
}

private static void ReportAmbiguity(CandidateSet candidates)
private static void ReportAmbiguity(CandidateState[] candidateState)
{
// If we get here it's the result of an ambiguity - we're OK with this
// being a littler slower and more allocatey.
var matches = new List<Endpoint>();
for (var i = 0; i < candidates.Count; i++)
for (var i = 0; i < candidateState.Length; i++)
{
if (candidates.IsValidCandidate(i))
ref var state = ref candidateState[i];
if (CandidateSet.IsValidCandidate(ref state))
{
matches.Add(candidates[i].Endpoint);
matches.Add(state.Endpoint);
}
}

Expand Down
44 changes: 25 additions & 19 deletions src/Http/Routing/src/Matching/DfaMatcher.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -101,7 +101,7 @@ public sealed override Task MatchAsync(HttpContext httpContext, EndpointSelector
// set of endpoints before we call the EndpointSelector.
//
// `candidateSet` is the mutable state that we pass to the EndpointSelector.
var candidateSet = new CandidateSet(candidates);
var candidateState = new CandidateState[candidateCount];

for (var i = 0; i < candidateCount; i++)
{
Expand All @@ -111,17 +111,13 @@ public sealed override Task MatchAsync(HttpContext httpContext, EndpointSelector
// candidate: readonly data about the endpoint and how to match
// state: mutable storarge for our processing
ref var candidate = ref candidates[i];
ref var state = ref candidateSet[i];
ref var state = ref candidateState[i];
state = new CandidateState(candidate.Endpoint, candidate.Score);

var flags = candidate.Flags;

// First process all of the parameters and defaults.
RouteValueDictionary values;
if ((flags & Candidate.CandidateFlags.HasSlots) == 0)
{
values = new RouteValueDictionary();
}
else
if ((flags & Candidate.CandidateFlags.HasSlots) != 0)
{
// The Slots array has the default values of the route values in it.
//
Expand All @@ -145,29 +141,29 @@ public sealed override Task MatchAsync(HttpContext httpContext, EndpointSelector
ProcessCatchAll(slots, candidate.CatchAll, path, segments);
}

values = RouteValueDictionary.FromArray(slots);
state.Values = RouteValueDictionary.FromArray(slots);
}

state.Values = values;

// Now that we have the route values, we need to process complex segments.
// Complex segments go through an old API that requires a fully-materialized
// route value dictionary.
var isMatch = true;
if ((flags & Candidate.CandidateFlags.HasComplexSegments) != 0)
{
if (!ProcessComplexSegments(candidate.Endpoint, candidate.ComplexSegments, path, segments, values))
state.Values ??= new RouteValueDictionary();
if (!ProcessComplexSegments(candidate.Endpoint, candidate.ComplexSegments, path, segments, state.Values))
{
candidateSet.SetValidity(i, false);
CandidateSet.SetValidity(ref state, false);
isMatch = false;
}
}

if ((flags & Candidate.CandidateFlags.HasConstraints) != 0)
{
if (!ProcessConstraints(candidate.Endpoint, candidate.Constraints, httpContext, values))
state.Values ??= new RouteValueDictionary();
if (!ProcessConstraints(candidate.Endpoint, candidate.Constraints, httpContext, state.Values))
{
candidateSet.SetValidity(i, false);
CandidateSet.SetValidity(ref state, false);
isMatch = false;
}
}
Expand All @@ -185,13 +181,23 @@ public sealed override Task MatchAsync(HttpContext httpContext, EndpointSelector
}
}

if (policyCount == 0)
if (policyCount == 0 && _isDefaultEndpointSelector)
{
// Fast path that avoids allocating the candidate set.
//
// We can use this when there are no policies and we're using the default selector.
DefaultEndpointSelector.Select(httpContext, context, candidateState);
return Task.CompletedTask;
}
else if (policyCount == 0)
{
// Perf: avoid a state machine if there are no polices
return _selector.SelectAsync(httpContext, context, candidateSet);
// Fast path that avoids a state machine.
//
// We can use this when there are no policies and a non-default selector.
return _selector.SelectAsync(httpContext, context, new CandidateSet(candidateState));
}

return SelectEndpointWithPoliciesAsync(httpContext, context, policies, candidateSet);
return SelectEndpointWithPoliciesAsync(httpContext, context, policies, new CandidateSet(candidateState));
}

internal (Candidate[] candidates, IEndpointSelectorPolicy[] policies) FindCandidateSet(
Expand Down
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