Avalonia/tests/Avalonia.LeakTests/BindingExpressionExtensions.cs

using System;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.Linq.Expressions;
using Avalonia.Data;
using Avalonia.Data.Converters;
using Avalonia.Data.Core;
using Avalonia.Data.Core.ExpressionNodes;
using Avalonia.Data.Core.Parsers;
using Avalonia.Utilities;

namespace Avalonia.LeakTests;

/// <summary>
/// Test extensions for creating BindingExpression instances from lambda expressions.
/// </summary>
internal static class BindingExpressionExtensions
{
    [RequiresUnreferencedCode(TrimmingMessages.ExpressionNodeRequiresUnreferencedCodeMessage)]
    [RequiresDynamicCode(TrimmingMessages.ExpressionNodeRequiresDynamicCodeMessage)]
    public static BindingExpression CreateBindingExpression<TIn, TOut>(
        TIn source,
        Expression<Func<TIn, TOut>> expression,
        IValueConverter? converter = null,
        CultureInfo? converterCulture = null,
        object? converterParameter = null,
        bool enableDataValidation = false,
        Optional<object?> fallbackValue = default,
        BindingMode mode = BindingMode.OneWay,
        BindingPriority priority = BindingPriority.LocalValue,
        object? targetNullValue = null,
        bool allowReflection = true)
        where TIn : class?
    {
        var path = BindingExpressionVisitor<TIn>.BuildPath(expression);
        var nodes = new List<ExpressionNode>();
        path.BuildExpression(nodes, out var _);
        var fallback = fallbackValue.HasValue ? fallbackValue.Value : AvaloniaProperty.UnsetValue;

        return new BindingExpression(
            source,
            nodes,
            fallback,
            converter: converter,
            converterCulture: converterCulture,
            converterParameter: converterParameter,
            enableDataValidation: enableDataValidation,
            mode: mode,
            priority: priority,
            targetNullValue: targetNullValue,
            targetTypeConverter: allowReflection ?
                TargetTypeConverter.GetReflectionConverter() :
                TargetTypeConverter.GetDefaultConverter());
    }
}