Revert "Fix processing chain interface (#556)"

This reverts commit 795c0fd.

.github/workflows/testing-matrix.yaml

@@ -12,7 +12,7 @@ concurrency:
   cancel-in-progress: true
 
 env:
-  TESTS: "FunctionTests ProcessingChainTests SDKTests RoomTests PublishDataTests PublishBufferCapturerTests VideoViewTests TrackTests"
+  TESTS: "FunctionTests SDKTests RoomTests PublishDataTests PublishBufferCapturerTests VideoViewTests TrackTests"
 
 jobs:
   test:

Sources/LiveKit/Protocols/ChainedProcessor.swift

@@ -17,7 +17,6 @@
 import Foundation
 
 public protocol ChainedProcessor: AnyObject {
-    associatedtype NextProcessorType: ChainedProcessor
     // Next object in the chain.
-    var nextProcessor: NextProcessorType? { get set }
+    var nextProcessor: Self? { get set }
 }

Sources/LiveKit/Support/ProcessingChain.swift

@@ -16,7 +16,7 @@
 
 import Foundation
 
-public class ProcessingChain<T: ChainedProcessor> {
+public class ProcessingChain<T: ChainedProcessor>: NSObject, Loggable {
     // MARK: - Public properties
 
     public var isProcessorsEmpty: Bool { countProcessors == 0 }
@@ -61,15 +61,15 @@ public class ProcessingChain<T: ChainedProcessor> {
         guard !processors.isEmpty else { return nil }
 
         for i in 0 ..< (processors.count - 1) {
-            processors[i].nextProcessor = processors[i + 1] as? T.NextProcessorType
+            processors[i].nextProcessor = processors[i + 1]
         }
         // The last one doesn't have a successor
         processors.last?.nextProcessor = nil
 
         return processors.first
     }
 
-    public func invokeChain<R>(_ fnc: @escaping (T) -> R) -> R? {
+    public func invokeProcessor<R>(_ fnc: @escaping (T) -> R) -> R? {
         guard let chain = buildProcessorChain() else { return nil }
         return fnc(chain)
     }

Tests/LiveKitTests/ProcessingChainTests.swift

@@ -17,13 +17,9 @@
 @testable import LiveKit
 import XCTest
 
-protocol MockProcessingInterface: ChainedProcessor {
-    func process(value: Int) -> Int
-}
-
 class ProcessingChainTests: XCTestCase {
     // Mock processor for testing
-    class MockProcessor: MockProcessingInterface {
+    final class MockProcessor: NSObject, ChainedProcessor {
         weak var nextProcessor: MockProcessor?
 
         func process(value: Int) -> Int {
@@ -115,7 +111,7 @@ class ProcessingChainTests: XCTestCase {
         chain.add(processor: processor2)
         chain.add(processor: processor3)
 
-        let result = chain.invokeChain { $0.process(value: 0) }
+        let result = chain.invokeProcessor { $0.process(value: 0) }
 
         // Each processor adds 1, so with 3 processors the final result should be 3
         XCTAssertEqual(result, 3)