O2 Exposer

O2 Exposer is a lightweight, high-performance member access library that enables fast runtime access to fields and properties of any object — without the overhead of slow reflection calls.

Traditional reflection in .NET can be slow and impact application performance, especially when accessing members repeatedly. O2.Exposer solves this by generating and caching delegate-based getters and setters for each member, ensuring:

• Reflection is performed only once per type (type caching)
• Each member’s getter/setter delegate is compiled once and reused indefinitely (delegate caching)

It also offers advanced filtering capabilities, allowing you to expose members based on access level (public/private), attributes, and accessibility rules. This makes it a perfect choice for creating serialization systems, debugging tools, runtime inspectors, and other utilities where dynamic and efficient member access is critical.

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🔑 Key Features

• 🔍 Access by Name
  Access private and public fields and properties via string names.

• ⚡ High Performance
  Reflection is only used once per member type. Afterwards, access is done through compiled delegates, completely reflection-free and with zero GC allocations.

• 🧠 Smart Caching
  Caches types, members, and delegates for maximum runtime performance.

• 🧹 GC-Free Access
  No boxing or allocations during get/set operations — ideal for performance-critical applications.

• 🎯 Flexible Filtering
  Filter exposed members by:

  • Access level (private, public, etc.)
  • Attributes (e.g. [SerializeField])
  • Accessibility (read, write)

• 🧩 Clean Value Access
  Get/set directly via .Value, with full type safety.

• 🛡 Interface-Based Control
  Restrict access via IExposedGetOnly<T> or IExposedSetOnly<T> interfaces.

🔢 Benchmark Comparison

Operation	Faster Method	Slower Method	Faster Mean (ns)	Slower Mean (ns)	× Faster	Performance Gain
Field Get	ExposedMemberGet	FieldInfoGet	0.2045 ns	2.3544 ns	~11.5×	~1051% faster
Field Set	ExposedMemberSet	FieldInfoSet	1.0329 ns	5.2493 ns	~5.1×	~408% faster
Property Get	ExposedMemberPropertyGet	PropertyInfoGet	0.8029 ns	6.7075 ns	~8.4×	~736% faster
Property Set	ExposedMemberPropertySet	PropertyInfoSet	1.0093 ns	9.9785 ns	~9.9×	~889% faster

📦 Installation

Download the latest release from the Releases page.

Extract the package and add the DLL file (O2.Exposer.dll) to your project references manually

📌 Sample Usage & 🚀 Quick Start

Using ExposedGroup (Recommended for Accessing Multiple Members)

ExposedGroup<TargetType> exposedGroup = new(TargetInstance);

Configure Optional Filters to Control Which Members Are Exposed

ExposerFilter exposerFilter = new ExposerFilter {
    GetterRequired = true,
    SetterRequired = true,
    RequiredAttributes = [
        typeof(PreserveBaseOverridesAttribute),
        typeof(CompilerGeneratedAttribute)
        // Add any other required attributes here
    ],
    AccessModifiers = AccessModifierTarget.Public | AccessModifierTarget.Protected | AccessModifierTarget.Internal
};

Create an Exposed Group with Filters

ExposedGroup<TargetType> filteredGroup = new ExposedGroup<TargetType>(TargetInstance, exposerFilter);

Retrieve a Member by Name and Expected Type

ExposedMember<string, TargetType> fieldExposed = exposedGroup.GetMember<string>("fieldName");

Convert Exposed Member into Interfaces with Restricted Access

IGetterOnlyMember<string, TargetType> readOnly = fieldExposed.AsReadOnly();
ISetterOnlyMember<string, TargetType> writeOnly = fieldExposed.AsSetOnly();

Expose a Property or Field by Name Without Filters

ExposedMember<int, TargetType> intField = ExposedMember<int, TargetType>.Expose("GetIntField", TargetInstance);