/// <summary>
/// Get a <see cref="NullCheckWalker"/> filtered by all null checks for <paramref name="parameter"/>.
/// </summary>
/// <param name="parameter">The <see cref="IParameterSymbol"/>.</param>
/// <param name="scope">The scope to walk.</param>
/// <param name="semanticModel">The <see cref="SemanticModel"/>.</param>
/// <param name="cancellationToken">The <see cref="CancellationToken"/>.</param>
/// <returns>A <see cref="NullCheckWalker"/> filtered by all null checks for <paramref name="parameter"/>.</returns>
public static NullCheckWalker For(IParameterSymbol parameter, SyntaxNode scope, SemanticModel semanticModel, CancellationToken cancellationToken)
{
var walker = NullCheckWalker.Borrow(scope.FirstAncestorOrSelf <MemberDeclarationSyntax>());
walker.Filter(parameter, semanticModel, cancellationToken);
return(walker);
}
/// <summary>
/// Check if <paramref name="parameter"/> is checked for null.
/// </summary>
/// <param name="parameter">The <see cref="IParameterSymbol"/>.</param>
/// <param name="scope">The scope to walk.</param>
/// <param name="semanticModel">The <see cref="SemanticModel"/>.</param>
/// <param name="cancellationToken">The <see cref="CancellationToken"/>.</param>
/// <returns>True if <paramref name="parameter"/> is checked for null.</returns>
public static bool IsChecked(IParameterSymbol parameter, SyntaxNode scope, SemanticModel semanticModel, CancellationToken cancellationToken)
{
if (parameter is null)
{
throw new System.ArgumentNullException(nameof(parameter));
}
using var walker = NullCheckWalker.Borrow(scope);
return(walker.TryGetFirst(parameter, semanticModel, cancellationToken, out _));
}
/// <summary>
/// Check if <paramref name="parameter"/> is checked for null.
/// </summary>
/// <param name="parameter">The <see cref="IParameterSymbol"/>.</param>
/// <param name="scope">The scope to walk.</param>
/// <param name="semanticModel">The <see cref="SemanticModel"/>.</param>
/// <param name="cancellationToken">The <see cref="CancellationToken"/>.</param>
/// <returns>True if <paramref name="parameter"/> is checked for null.</returns>
public static bool IsChecked(IParameterSymbol parameter, SyntaxNode scope, SemanticModel semanticModel, CancellationToken cancellationToken)
{
if (parameter is null ||
scope is null)
{
return(false);
}
using (var walker = NullCheckWalker.Borrow(scope))
{
return(walker.TryGetFirst(parameter, semanticModel, cancellationToken, out _));
}
}
/// <summary>
/// Check if <paramref name="parameter"/> is checked for null before <paramref name="location"/>.
/// </summary>
/// <param name="parameter">The <see cref="IParameterSymbol"/>.</param>
/// <param name="location">The location where we want to know if <paramref name="parameter"/> is checked for null.</param>
/// <param name="semanticModel">The <see cref="SemanticModel"/>.</param>
/// <param name="cancellationToken">The <see cref="CancellationToken"/>.</param>
/// <returns>True if <paramref name="parameter"/> is checked for null before <paramref name="location"/>.</returns>
public static bool IsCheckedBefore(IParameterSymbol parameter, SyntaxNode location, SemanticModel semanticModel, CancellationToken cancellationToken)
{
if (parameter is null ||
location is null)
{
return(false);
}
using (var walker = NullCheckWalker.Borrow(location.FirstAncestorOrSelf <MemberDeclarationSyntax>()))
{
return(walker.TryGetFirst(parameter, semanticModel, cancellationToken, out var check) &&
location.TryFirstAncestorOrSelf(out ExpressionSyntax? expression) &&
check.IsExecutedBefore(expression) == ExecutedBefore.Yes);
}
}
/// <summary>
/// Check if <paramref name="parameter"/> is checked for null before <paramref name="location"/>.
/// </summary>
/// <param name="parameter">The <see cref="IParameterSymbol"/>.</param>
/// <param name="location">The location where we want to know if <paramref name="parameter"/> is checked for null.</param>
/// <param name="semanticModel">The <see cref="SemanticModel"/>.</param>
/// <param name="cancellationToken">The <see cref="CancellationToken"/>.</param>
/// <returns>True if <paramref name="parameter"/> is checked for null before <paramref name="location"/>.</returns>
public static bool IsCheckedBefore(IParameterSymbol parameter, SyntaxNode location, SemanticModel semanticModel, CancellationToken cancellationToken)
{
if (parameter is null)
{
throw new System.ArgumentNullException(nameof(parameter));
}
if (location is null)
{
throw new System.ArgumentNullException(nameof(location));
}
if (location.FirstAncestorOrSelf <MemberDeclarationSyntax>() is { } member)
{
using var walker = NullCheckWalker.Borrow(member);
return(walker.TryGetFirst(parameter, semanticModel, cancellationToken, out var check) &&
location.TryFirstAncestorOrSelf(out ExpressionSyntax? expression) &&
check.IsExecutedBefore(expression) == ExecutedBefore.Yes);
}
return(false);
}