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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
using System;
using System.Collections.Immutable;
using System.Diagnostics;
using System.Linq;
using Microsoft.CodeAnalysis.Shared.Extensions;
using Roslyn.Utilities;
namespace Microsoft.CodeAnalysis.Shared.Utilities
{
internal partial class SymbolEquivalenceComparer
{
private class GetHashCodeVisitor
{
private readonly SymbolEquivalenceComparer _symbolEquivalenceComparer;
private readonly bool _compareMethodTypeParametersByIndex;
private readonly bool _objectAndDynamicCompareEqually;
private readonly Func<int, IParameterSymbol, int> _parameterAggregator;
private readonly Func<int, ISymbol, int> _symbolAggregator;
public GetHashCodeVisitor(
SymbolEquivalenceComparer symbolEquivalenceComparer,
bool compareMethodTypeParametersByIndex,
bool objectAndDynamicCompareEqually)
{
_symbolEquivalenceComparer = symbolEquivalenceComparer;
_compareMethodTypeParametersByIndex = compareMethodTypeParametersByIndex;
_objectAndDynamicCompareEqually = objectAndDynamicCompareEqually;
_parameterAggregator = (acc, sym) => Hash.Combine(symbolEquivalenceComparer.ParameterEquivalenceComparer.GetHashCode(sym), acc);
_symbolAggregator = (acc, sym) => GetHashCode(sym, acc);
}
public int GetHashCode(ISymbol? x, int currentHash)
{
if (x == null)
return 0;
x = UnwrapAlias(x);
// Special case. If we're comparing signatures then we want to compare 'object'
// and 'dynamic' as the same. However, since they're different types, we don't
// want to bail out using the above check.
if (x.Kind == SymbolKind.DynamicType ||
(_objectAndDynamicCompareEqually && IsObjectType(x)))
{
return Hash.Combine(GetNullableAnnotationsHashCode((ITypeSymbol)x), Hash.Combine(typeof(IDynamicTypeSymbol), currentHash));
}
return GetHashCodeWorker(x, currentHash);
}
private int GetNullableAnnotationsHashCode(ITypeSymbol type)
=> _symbolEquivalenceComparer._ignoreNullableAnnotations ? 0 : ((int)type.NullableAnnotation).GetHashCode();
private int GetHashCodeWorker(ISymbol x, int currentHash)
=> x.Kind switch
{
SymbolKind.ArrayType => CombineHashCodes((IArrayTypeSymbol)x, currentHash),
SymbolKind.Assembly => CombineHashCodes((IAssemblySymbol)x, currentHash),
SymbolKind.Event => CombineHashCodes((IEventSymbol)x, currentHash),
SymbolKind.Field => CombineHashCodes((IFieldSymbol)x, currentHash),
SymbolKind.Label => CombineHashCodes((ILabelSymbol)x, currentHash),
SymbolKind.Local => CombineHashCodes((ILocalSymbol)x, currentHash),
SymbolKind.Method => CombineHashCodes((IMethodSymbol)x, currentHash),
SymbolKind.NetModule => CombineHashCodes((IModuleSymbol)x, currentHash),
SymbolKind.NamedType => CombineHashCodes((INamedTypeSymbol)x, currentHash),
SymbolKind.Namespace => CombineHashCodes((INamespaceSymbol)x, currentHash),
SymbolKind.Parameter => CombineHashCodes((IParameterSymbol)x, currentHash),
SymbolKind.PointerType => CombineHashCodes((IPointerTypeSymbol)x, currentHash),
SymbolKind.Property => CombineHashCodes((IPropertySymbol)x, currentHash),
SymbolKind.RangeVariable => CombineHashCodes((IRangeVariableSymbol)x, currentHash),
SymbolKind.TypeParameter => CombineHashCodes((ITypeParameterSymbol)x, currentHash),
SymbolKind.Preprocessing => CombineHashCodes((IPreprocessingSymbol)x, currentHash),
_ => -1,
};
private int CombineHashCodes(IArrayTypeSymbol x, int currentHash)
{
return
Hash.Combine(GetNullableAnnotationsHashCode(x),
Hash.Combine(x.Rank,
GetHashCode(x.ElementType, currentHash)));
}
private int CombineHashCodes(IAssemblySymbol x, int currentHash)
=> Hash.Combine(_symbolEquivalenceComparer._assemblyComparerOpt?.GetHashCode(x) ?? 0, currentHash);
private int CombineHashCodes(IFieldSymbol x, int currentHash)
{
return
Hash.Combine(x.Name,
GetHashCode(x.ContainingSymbol, currentHash));
}
private static int CombineHashCodes(ILabelSymbol x, int currentHash)
{
return
Hash.Combine(x.Name,
Hash.Combine(x.Locations.FirstOrDefault(), currentHash));
}
private static int CombineHashCodes(ILocalSymbol x, int currentHash)
=> Hash.Combine(x.Locations.FirstOrDefault(), currentHash);
private static int CombineHashCodes<T>(ImmutableArray<T> array, int currentHash, Func<int, T, int> func)
=> array.Aggregate<int, T>(currentHash, func);
private int CombineHashCodes(IMethodSymbol x, int currentHash)
{
currentHash = Hash.Combine(x.MetadataName, currentHash);
if (x.MethodKind == MethodKind.AnonymousFunction)
{
return Hash.Combine(x.Locations.FirstOrDefault(), currentHash);
}
currentHash =
Hash.Combine(IsPartialMethodImplementationPart(x),
Hash.Combine(IsPartialMethodDefinitionPart(x),
Hash.Combine(x.IsDefinition,
Hash.Combine(IsConstructedFromSelf(x),
Hash.Combine(x.Arity,
Hash.Combine(x.Parameters.Length,
Hash.Combine(x.Name, currentHash)))))));
var checkContainingType = CheckContainingType(x);
if (checkContainingType)
{
currentHash = GetHashCode(x.ContainingSymbol, currentHash);
}
currentHash =
CombineHashCodes(x.Parameters, currentHash, _parameterAggregator);
return IsConstructedFromSelf(x)
? currentHash
: CombineHashCodes(x.TypeArguments, currentHash, _symbolAggregator);
}
private int CombineHashCodes(IModuleSymbol x, int currentHash)
=> CombineHashCodes(x.ContainingAssembly, Hash.Combine(x.Name, currentHash));
private int CombineHashCodes(INamedTypeSymbol x, int currentHash)
{
currentHash = CombineNamedTypeHashCode(x, currentHash);
if (x is IErrorTypeSymbol errorType)
{
foreach (var candidate in errorType.CandidateSymbols)
{
if (candidate is INamedTypeSymbol candidateNamedType)
{
currentHash = CombineNamedTypeHashCode(candidateNamedType, currentHash);
}
}
}
return currentHash;
}
private int CombineNamedTypeHashCode(INamedTypeSymbol x, int currentHash)
{
if (x.IsTupleType)
{
return Hash.Combine(currentHash, Hash.CombineValues(x.TupleElements));
}
// If we want object and dynamic to be the same, and this is 'object', then return
// the same hash we do for 'dynamic'.
currentHash =
Hash.Combine((int)GetTypeKind(x),
Hash.Combine(IsConstructedFromSelf(x),
Hash.Combine(x.Arity,
Hash.Combine(x.Name,
Hash.Combine(x.IsAnonymousType,
Hash.Combine(x.IsUnboundGenericType,
Hash.Combine(GetNullableAnnotationsHashCode(x),
GetHashCode(x.ContainingSymbol, currentHash))))))));
if (x.IsAnonymousType)
{
return CombineAnonymousTypeHashCode(x, currentHash);
}
return IsConstructedFromSelf(x) || x.IsUnboundGenericType
? currentHash
: CombineHashCodes(x.TypeArguments, currentHash, _symbolAggregator);
}
private int CombineAnonymousTypeHashCode(INamedTypeSymbol x, int currentHash)
{
if (x.TypeKind == TypeKind.Delegate)
{
return GetHashCode(x.DelegateInvokeMethod, currentHash);
}
else
{
var xMembers = x.GetValidAnonymousTypeProperties();
return xMembers.Aggregate(currentHash, (a, p) =>
{
return Hash.Combine(p.Name,
Hash.Combine(p.IsReadOnly,
GetHashCode(p.Type, a)));
});
}
}
private int CombineHashCodes(INamespaceSymbol x, int currentHash)
{
if (x.IsGlobalNamespace && _symbolEquivalenceComparer._assemblyComparerOpt == null)
{
// Exclude global namespace's container's hash when assemblies can differ.
return Hash.Combine(x.Name, currentHash);
}
return
Hash.Combine(x.IsGlobalNamespace,
Hash.Combine(x.Name,
GetHashCode(x.ContainingSymbol, currentHash)));
}
private int CombineHashCodes(IParameterSymbol x, int currentHash)
{
return
Hash.Combine(x.IsRefOrOut(),
Hash.Combine(x.Name,
GetHashCode(x.Type,
GetHashCode(x.ContainingSymbol, currentHash))));
}
private int CombineHashCodes(IPointerTypeSymbol x, int currentHash)
{
return
Hash.Combine(typeof(IPointerTypeSymbol).GetHashCode(),
GetHashCode(x.PointedAtType, currentHash));
}
private int CombineHashCodes(IPropertySymbol x, int currentHash)
{
currentHash =
Hash.Combine(x.IsIndexer,
Hash.Combine(x.Name,
Hash.Combine(x.Parameters.Length,
GetHashCode(x.ContainingSymbol, currentHash))));
return CombineHashCodes(x.Parameters, currentHash, _parameterAggregator);
}
private int CombineHashCodes(IEventSymbol x, int currentHash)
{
return
Hash.Combine(x.Name,
GetHashCode(x.ContainingSymbol, currentHash));
}
public int CombineHashCodes(ITypeParameterSymbol x, int currentHash)
{
Debug.Assert(
(x.TypeParameterKind == TypeParameterKind.Method && IsConstructedFromSelf(x.DeclaringMethod!)) ||
(x.TypeParameterKind == TypeParameterKind.Type && IsConstructedFromSelf(x.ContainingType)) ||
x.TypeParameterKind == TypeParameterKind.Cref);
currentHash =
Hash.Combine(x.Ordinal,
Hash.Combine((int)x.TypeParameterKind, currentHash));
if (x.TypeParameterKind == TypeParameterKind.Method && _compareMethodTypeParametersByIndex)
{
return currentHash;
}
if (x.TypeParameterKind == TypeParameterKind.Type && x.ContainingType.IsAnonymousType)
{
// Anonymous type type parameters compare by index as well to prevent
// recursion.
return currentHash;
}
if (x.TypeParameterKind == TypeParameterKind.Cref)
{
return currentHash;
}
return
GetHashCode(x.ContainingSymbol, currentHash);
}
private static int CombineHashCodes(IRangeVariableSymbol x, int currentHash)
=> Hash.Combine(x.Locations.FirstOrDefault(), currentHash);
private static int CombineHashCodes(IPreprocessingSymbol x, int currentHash)
=> Hash.Combine(x.GetHashCode(), currentHash);
}
}
}
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