Extension handler support in DivState

client/ios/DivKit/DivExtensionHandler.swift

@@ -18,7 +18,17 @@ import LayoutKit
 public protocol DivExtensionHandler: AccessibilityContaining {
   /// A unique identifier for the extension.
   var id: String { get }
-
+  
+  /// Notifies extension handler that div will be processed by DivKit.
+  ///
+  /// - Parameters:
+  ///   - div: The `DivBase` to which extension handler is attached.
+  ///   - context: The context in which the block is being modeled.
+  func accept(
+    div: DivBase,
+    context: DivBlockModelingContext
+  )
+  
   /// Applies additional properties to the block before the base properties.
   ///
   /// - Parameters:
@@ -49,6 +59,11 @@ public protocol DivExtensionHandler: AccessibilityContaining {
 }
 
 extension DivExtensionHandler {
+  public func accept(
+    div: DivBase,
+    context: DivBlockModelingContext
+  ) {}
+  
   public func applyBeforeBaseProperties(
     to block: Block,
     div _: DivBase,

client/ios/DivKit/Extensions/DivBase/DivBaseExtensions.swift

@@ -14,6 +14,12 @@ extension DivBase {
     customAccessibilityParams: CustomAccessibilityParams = .default,
     clipToBounds: Bool = true
   ) throws -> Block {
+    let extensionHandlers = context.getExtensionHandlers(for: self)
+    
+    extensionHandlers.forEach {
+      $0.accept(div: self, context: context)
+    }
+    
     let expressionResolver = context.expressionResolver
     let statePath = context.parentDivStatePath ?? DivData.rootPath
 
@@ -26,7 +32,7 @@ extension DivBase {
 
     var block = try block()
 
-    let extensionHandlers = context.getExtensionHandlers(for: self)
+    
     extensionHandlers.forEach {
       block = $0.applyBeforeBaseProperties(to: block, div: self, context: context)
     }