refactor(ios): replace DispatchQueue with Swift concurrency and release SVGKit memory

Author: pinpong

ios/GoogleMapViewImpl.swift

@@ -355,7 +355,7 @@ GMSIndoorDisplayDelegate {
   ) -> NitroModules.Promise<String?> {
     let promise = Promise<String?>()
 
-    DispatchQueue.main.async {
+    onMainAsync {
       guard let mapView = self.mapView else {
         promise.resolve(withResult: nil)
         return
@@ -847,12 +847,3 @@ GMSIndoorDisplayDelegate {
     }
   }
 }
-
-@inline(__always)
-func onMain(_ block: @escaping () -> Void) {
-  if Thread.isMainThread {
-    block()
-  } else {
-    DispatchQueue.main.async { block() }
-  }
-}

ios/LocationHandler.swift

@@ -34,7 +34,7 @@ final class LocationHandler: NSObject, CLLocationManagerDelegate {
   }
 
   func showLocationDialog() {
-    DispatchQueue.main.async {
+    onMainAsync { [weak self] in
       guard let vc = Self.topMostViewController() else { return }
       let title =
         Bundle.main.object(forInfoDictionaryKey: "LocationNotAvailableTitle")
@@ -61,7 +61,7 @@ final class LocationHandler: NSObject, CLLocationManagerDelegate {
           title: openLocationSettingsButton ?? "Open settings",
           style: .default
         ) { _ in
-          self.openLocationSettings()
+          self?.openLocationSettings()
         }
       )
       vc.present(alert, animated: true, completion: nil)
@@ -78,7 +78,7 @@ final class LocationHandler: NSObject, CLLocationManagerDelegate {
   }
 
   func openLocationSettings() {
-    DispatchQueue.main.async {
+    onMainAsync {
       let openSettings = {
         if #available(iOS 18.3, *) {
           guard

ios/MapHelper.swift

@@ -18,3 +18,23 @@ func withCATransaction(
   body()
   CATransaction.commit()
 }
+
+@MainActor @inline(__always)
+func onMain(_ block: @escaping @MainActor () -> Void) {
+  if Thread.isMainThread {
+    block()
+  } else {
+    Task { @MainActor in block() }
+  }
+}
+
+@inline(__always)
+func onMainAsync(
+  _ block: @MainActor @escaping () async -> Void
+) {
+  if Thread.isMainThread {
+    Task { @MainActor in await block() }
+  } else {
+    Task { @MainActor in await block() }
+  }
+}

ios/MapMarkerBuilder.swift

@@ -3,13 +3,12 @@ import SVGKit
 import UIKit
 
 final class MapMarkerBuilder {
-  private let iconCache = NSCache<NSString, UIImage>()
+  private let iconCache: NSCache<NSNumber, UIImage> = {
+    let c = NSCache<NSNumber, UIImage>()
+    c.countLimit = 512
+    return c
+  }()
   private var tasks: [String: Task<Void, Never>] = [:]
-  private let queue = DispatchQueue(
-    label: "map.marker.render",
-    qos: .userInitiated,
-    attributes: .concurrent
-  )
 
   func build(_ m: RNMarker, icon: UIImage?) -> GMSMarker {
     let marker = GMSMarker(
@@ -35,7 +34,8 @@ final class MapMarkerBuilder {
     }
     m.zIndex.map { marker.zIndex = Int32($0) }
 
-    DispatchQueue.main.asyncAfter(deadline: .now() + 0.25) { [weak marker] in
+    onMainAsync { [weak marker] in
+      try? await Task.sleep(nanoseconds: 250_000_000)
       marker?.tracksViewChanges = false
     }
 
@@ -99,7 +99,8 @@ final class MapMarkerBuilder {
           )
         }
 
-        DispatchQueue.main.asyncAfter(deadline: .now() + 0.25) { [weak m] in
+        onMainAsync { [weak m] in
+          try? await Task.sleep(nanoseconds: 250_000_000)
           m?.tracksViewChanges = false
         }
       }
@@ -144,7 +145,8 @@ final class MapMarkerBuilder {
       guard let self else { return }
       defer { self.tasks.removeValue(forKey: id) }
 
-      let img = await self.renderUIImage(m)
+      let scale = UIScreen.main.scale
+      let img = await self.renderUIImage(m, scale)
       guard let img, !Task.isCancelled else { return }
 
       self.iconCache.setObject(img, forKey: key)
@@ -172,65 +174,38 @@ final class MapMarkerBuilder {
     iconCache.removeAllObjects()
   }
 
-  private func renderUIImage(_ m: RNMarker) async -> UIImage? {
-    guard let iconSvg = m.iconSvg else {
-      return nil
-    }
-
-    return await withTaskCancellationHandler(
-      operation: {
-        await withCheckedContinuation {
-          (cont: CheckedContinuation<UIImage?, Never>) in
-          queue.async {
-            if Task.isCancelled {
-              cont.resume(returning: nil)
-              return
-            }
-
-            let targetW = max(1, Int(CGFloat(iconSvg.width)))
-            let targetH = max(1, Int(CGFloat(iconSvg.height)))
-            let size = CGSize(width: targetW, height: targetH)
-
-            guard
-              let data = iconSvg.svgString.data(using: .utf8),
-              let svgImg = SVGKImage(data: data)
-            else {
-              cont.resume(returning: nil)
-              return
-            }
-
-            svgImg.size = size
-
-            if Task.isCancelled {
-              cont.resume(returning: nil)
-              return
-            }
-
-            guard let base = svgImg.uiImage else {
-              cont.resume(returning: nil)
-              return
-            }
-
-            let scale = UIScreen.main.scale
-            let img: UIImage
-            if let cg = base.cgImage {
-              img = UIImage(cgImage: cg, scale: scale, orientation: .up)
-            } else {
-              let fmt = UIGraphicsImageRendererFormat.default()
-              fmt.opaque = false
-              fmt.scale = scale
-              let renderer = UIGraphicsImageRenderer(size: size, format: fmt)
-              img = renderer.image { _ in
-                base.draw(in: CGRect(origin: .zero, size: size))
-              }
-            }
-
-            cont.resume(returning: img)
-          }
-        }
+  private func renderUIImage(_ m: RNMarker, _ scale: CGFloat) async -> UIImage? {
+    guard let iconSvg = m.iconSvg,
+          let data = iconSvg.svgString.data(using: .utf8)
+    else { return nil }
 
-      },
-      onCancel: {}
+    let size = CGSize(
+      width: max(1, CGFloat(iconSvg.width)),
+      height: max(1, CGFloat(iconSvg.height))
     )
+
+    return await Task.detached(priority: .userInitiated) {
+      autoreleasepool {
+        guard let svgImg = SVGKImage(data: data) else { return nil }
+        svgImg.size = size
+
+        guard !Task.isCancelled else { return nil }
+        guard let base = svgImg.uiImage else { return nil }
+
+        if let cg = base.cgImage {
+          return UIImage(cgImage: cg, scale: scale, orientation: .up)
+        }
+        guard !Task.isCancelled else { return nil }
+        let fmt = UIGraphicsImageRendererFormat.default()
+        fmt.opaque = false
+        fmt.scale = scale
+        guard !Task.isCancelled else { return nil }
+        let renderer = UIGraphicsImageRenderer(size: size, format: fmt)
+        return renderer.image { _ in
+          base.draw(in: CGRect(origin: .zero, size: size))
+        }
+      }
+    }.value
   }
+
 }

ios/RNGoogleMapsPlusView.swift

@@ -34,15 +34,13 @@ final class RNGoogleMapsPlusView: HybridRNGoogleMapsPlusViewSpec {
   func afterUpdate() {
     if !propsInitialized {
       propsInitialized = true
-      Task { @MainActor in
-        let options = GMSMapViewOptions()
-        initialProps?.mapId.map { options.mapID = GMSMapID(identifier: $0) }
-        initialProps?.liteMode.map { _ in /* not supported */ }
-        initialProps?.camera.map {
-          options.camera = $0.toGMSCameraPosition(current: nil)
-        }
-        impl.initMapView(googleMapOptions: options)
+      let options = GMSMapViewOptions()
+      initialProps?.mapId.map { options.mapID = GMSMapID(identifier: $0) }
+      initialProps?.liteMode.map { _ in /* not supported */ }
+      initialProps?.camera.map {
+        options.camera = $0.toGMSCameraPosition(current: nil)
       }
+      impl.initMapView(googleMapOptions: options)
     }
   }
 

ios/extensions/RNMarker+Extension.swift

@@ -17,14 +17,13 @@ extension RNMarker {
   func markerStyleEquals(_ b: RNMarker) -> Bool {
     iconSvg?.width == b.iconSvg?.width && iconSvg?.height == b.iconSvg?.height
       && iconSvg?.svgString == b.iconSvg?.svgString
-
   }
 
-  func styleHash() -> NSString {
+  func styleHash() -> NSNumber {
     var hasher = Hasher()
     hasher.combine(iconSvg?.width)
     hasher.combine(iconSvg?.height)
     hasher.combine(iconSvg?.svgString)
-    return String(hasher.finalize()) as NSString
+    return NSNumber(value: hasher.finalize())
   }
 }