Actor BackgroundDeallocationQueue (#419)

Sources/Verge/Library/BackgroundDeallocationQueue.swift

@@ -20,43 +20,40 @@
 // THE SOFTWARE.
 
 import Foundation
+import Collections
 
-final class BackgroundDeallocationQueue {
+actor BackgroundDeallocationQueue {
 
-  private let queue = DispatchQueue.init(label: "org.VergeGroup.deallocQueue", qos: .background)
-
-  private var buffer: ContiguousArray<Unmanaged<AnyObject>> = .init()
-
-  private let lock = NSLock()
+  private var buffer: Deque<Unmanaged<AnyObject>> = .init()
 
   func releaseObjectInBackground(object: AnyObject) {
 
     let innerCurrentRef = Unmanaged.passRetained(object)
 
-    lock.lock()
-
     let isFirstEntry = buffer.isEmpty
     buffer.append(innerCurrentRef)
 
-    lock.unlock()
-
     if isFirstEntry {
-      queue.asyncAfter(deadline: .now() + 0.1) {
-        self.drain()
+      Task {
+        // accumulate objects to dealloc for batching
+        try? await Task.sleep(nanoseconds: 1_000_000)
+        await self.drain()
       }
     }
   }
 
-  func drain() {
+  func drain() async {
 
-    lock.lock()
-    let block = buffer
-    buffer = .init()
-    lock.unlock()
+    guard buffer.isEmpty == false else {
+      return
+    }
 
-    for pointer in block {
+    while let pointer = buffer.popFirst() {
       pointer.release()
+      await Task.yield()
     }
 
+    await drain()
+
   }
 }

Sources/Verge/Store/Changes.swift

@@ -24,7 +24,7 @@ import Foundation
 #if !COCOAPODS
 #endif
 
-private let changesDeallocationQueue = BackgroundDeallocationQueue()
+private let _shared_changesDeallocationQueue = BackgroundDeallocationQueue()
 
 public protocol AnyChangesType: AnyObject, Sendable {
 
@@ -169,7 +169,9 @@ public final class Changes<Value: Equatable>: @unchecked Sendable, ChangesType,
   deinit {
     vergeSignpostEvent("Changes.deinit", label: "\(type(of: self))")
 
-    changesDeallocationQueue.releaseObjectInBackground(object: innerBox)
+    Task { [innerBox] in
+      await _shared_changesDeallocationQueue.releaseObjectInBackground(object: innerBox)
+    }
   }
 
   @inline(__always)