Unity SerializedProperty extensions and utilities

SerializedPropertyExtensions.cs

using System;
using System.Collections;
using UnityEditor;

namespace MikeSchweitzer
{
    public static class SerializedPropertyExtensions
    {
        public static T[] GetAllValues<T>(this SerializedProperty property)
        {
            var targetObjects = property.serializedObject.targetObjects;

            var values = new T[targetObjects.Length];
            for (var i = 0; i < targetObjects.Length; ++i)
                values[i] = property.GetValue<T>(i);
            return values;
        }

        public static void GetAllValues<T>(this SerializedProperty property, ref T[] values)
        {
            var targetObjects = property.serializedObject.targetObjects;

            if (values == null)
                values = new T[targetObjects.Length];
            else
                Array.Resize(ref values, targetObjects.Length);

            for (var i = 0; i < targetObjects.Length; ++i)
                values[i] = property.GetValue<T>(i);
        }

        public static T GetValue<T>(this SerializedProperty property, int targetObjectIndex = -1)
        {
            var value = targetObjectIndex < 0
                ? (object)property.serializedObject.targetObject
                : property.serializedObject.targetObjects[targetObjectIndex];

            var path = property.propertyPath;
            var prevIndex = -1;
            do
            {
                var nextIndex = path.IndexOf('.', prevIndex + 1);

                var subPathLength = (nextIndex < 0 ? path.Length : nextIndex) - prevIndex - 1;
                var subPath = path.AsSpan(prevIndex + 1, subPathLength).ToString();

                if (subPath == "Array")
                {
                    // list/array propertyPath values are weird and look like this
                    // {PropertyName}.Array.data[{ListIndex}]
                    // e.g.
                    // AudioLines.Array.data[0]
                    // RandomClipEntries.Array.data[0].ClipReference
                    var listIndexStart = path.IndexOf('[', nextIndex + 1) + 1;
                    var listIndexLength = path.IndexOf(']', listIndexStart) - listIndexStart;

                    var listIndexSpan = path.AsSpan(listIndexStart, listIndexLength);
                    var listIndex = int.Parse(listIndexSpan);

                    var enumerable = (IEnumerable)value;
                    var enumerator = enumerable!.GetEnumerator();
                    using var disposeDummy = enumerator as IDisposable;
                    var hasItemAtIndex = false;
                    for (var i = 0; i <= listIndex; ++i)
                        hasItemAtIndex = enumerator.MoveNext();
                    value = hasItemAtIndex ? enumerator.Current : null;

                    // have to move the prevIndex past the closing bracket and to the next dot
                    // OR the end of the string, whichever it happens to be
                    prevIndex = listIndexStart + listIndexLength + 1;
                }
                else
                {
                    value = value!.GetType().GetField(subPath).GetValue(value);

                    prevIndex = nextIndex;
                }
            } while (prevIndex >= 0 && prevIndex < path.Length);

            return (T)value;
        }
    }
}