private static MethodDeclarationSyntax EqualsImplementation(EquatableGenerationContext context)
{
return(MethodDeclaration(
PredefinedType(Token(SyntaxKind.BoolKeyword)),
Identifier("Equals")
).AddModifiers(
Token(SyntaxKind.PublicKeyword),
Token(SyntaxKind.OverrideKeyword)
).AddParameterListParameters(
Parameter(Identifier("obj"))
.WithType(PredefinedType(Token(SyntaxKind.ObjectKeyword)))
).AddBodyStatements(
ReturnStatement(
InvocationExpression(IdentifierName("Equals"))
.AddArgumentListArguments(
Argument(
BinaryExpression(
SyntaxKind.AsExpression,
IdentifierName("obj"),
IdentifierName(context.ClassIdentifier)
)
)
)
)
));
}
private static MethodDeclarationSyntax GetHashCode(EquatableGenerationContext context)
{
var statements = new List <StatementSyntax>()
{
LocalDeclarationStatement(
VariableDeclaration(PredefinedType(Token(SyntaxKind.IntKeyword)))
.AddVariables(
VariableDeclarator(Identifier("HashingBase"))
.WithInitializer(EqualsValueClause(CastExpression(
PredefinedType(Token(SyntaxKind.IntKeyword)),
LiteralExpression(SyntaxKind.NumericLiteralExpression, Literal(2166136261))
)))
)
).AddModifiers(Token(SyntaxKind.ConstKeyword)),
LocalDeclarationStatement(
VariableDeclaration(PredefinedType(Token(SyntaxKind.IntKeyword)))
.AddVariables(
VariableDeclarator(Identifier("HashingMultiplier"))
.WithInitializer(
EqualsValueClause(
LiteralExpression(SyntaxKind.NumericLiteralExpression, Literal(16777619))
)
)
)
).AddModifiers(Token(SyntaxKind.ConstKeyword)),
LocalDeclarationStatement(
VariableDeclaration(IdentifierName("var"))
.AddVariables(
VariableDeclarator(Identifier("hashCode"))
.WithInitializer(EqualsValueClause(IdentifierName("HashingBase")))
)
)
};
statements.AddRange(context.Properties.Select(property => HashCodeForProperty(property, context.CanBeNull(property))));
statements.Add(ReturnStatement(IdentifierName("hashCode")));
return(MethodDeclaration(PredefinedType(Token(SyntaxKind.IntKeyword)), Identifier("GetHashCode"))
.AddModifiers(Token(SyntaxKind.PublicKeyword))
.AddModifiers(Token(SyntaxKind.OverrideKeyword))
.AddBodyStatements(
CheckedStatement(
SyntaxKind.UncheckedStatement,
Block(statements.ToArray())
)
));
}
public Task <SyntaxList <MemberDeclarationSyntax> > GenerateAsync(TransformationContext context, IProgress <Diagnostic> progress, CancellationToken cancellationToken)
{
var targetClass = (ClassDeclarationSyntax)context.ProcessingNode;
var equatableContext = EquatableGenerationContext.Create(targetClass, context.Compilation, context.SemanticModel);
var resultClass = targetClass
.WithBaseList(GetBaseList(equatableContext))
.WithAttributeLists(List(new AttributeListSyntax[0]))
.WithModifiers(TokenList(Token(SyntaxKind.PartialKeyword)))
.WithMembers(List(new MemberDeclarationSyntax[]
{
EqualsImplementation(equatableContext),
EquatableImplementation(equatableContext),
GetHashCode(equatableContext)
}));
return(Task.FromResult(List <MemberDeclarationSyntax>().Add(resultClass)));
}
private BaseListSyntax GetBaseList(EquatableGenerationContext context)
{
if (context.IsIEquatableTDefined)
{
return(null);
}
return(BaseList(
SingletonSeparatedList <BaseTypeSyntax>(
SimpleBaseType(
QualifiedName(IdentifierName("System"), GenericName(Identifier("IEquatable"))
.WithTypeArgumentList(
TypeArgumentList(
SingletonSeparatedList <TypeSyntax>(IdentifierName(context.ClassIdentifier))
)
)
)
)
)
));
}
private static MethodDeclarationSyntax EquatableImplementation(EquatableGenerationContext context)
{
var notNullCheck = BinaryExpression(SyntaxKind.NotEqualsExpression,
IdentifierName("other"),
LiteralExpression(SyntaxKind.NullLiteralExpression)
);
var body = context.Properties.Select(property => EqualsCondition(property, context.IsEnumerable(property)))
.Aggregate(
notNullCheck,
(prev, curr) => BinaryExpression(SyntaxKind.LogicalAndExpression, prev, curr)
);
return(MethodDeclaration(
PredefinedType(Token(SyntaxKind.BoolKeyword)),
Identifier("Equals")
)
.AddModifiers(Token(SyntaxKind.PublicKeyword))
.AddParameterListParameters(
Parameter(Identifier("other")).WithType(IdentifierName(context.ClassIdentifier))
)
.AddBodyStatements(ReturnStatement(body)));
}