BridgeJS: Add lifetime tracking mode to BridgeJSLink

Author: kateinoigakukun

Plugins/BridgeJS/Sources/BridgeJSLink/BridgeJSLink.swift

@@ -10,12 +10,16 @@ import BridgeJSUtilities
 public struct BridgeJSLink {
     var skeletons: [BridgeJSSkeleton] = []
     let sharedMemory: Bool
+    /// Whether to track the lifetime of Swift objects.
+    ///
+    /// This is useful for debugging memory issues.
+    let enableLifetimeTracking: Bool = false
     private let namespaceBuilder = NamespaceBuilder()
     private let intrinsicRegistry = JSIntrinsicRegistry()
 
     public init(
         skeletons: [BridgeJSSkeleton] = [],
-        sharedMemory: Bool
+        sharedMemory: Bool = false
     ) {
         self.skeletons = skeletons
         self.sharedMemory = sharedMemory
@@ -50,8 +54,33 @@ public struct BridgeJSLink {
         }
         """
 
-    let swiftHeapObjectClassJs = """
+    let lifetimeTrackingClassJs = """
+        const TRACKING = {
+            wrap: (pointer, deinit, prototype, state) => {
+                console.log(JSON.stringify({ DEBUG: true, event: "WRP", class: prototype.constructor.name, state }));
+            },
+            release: (obj) => {
+                console.log(JSON.stringify({ DEBUG: true, event: "REL", class: obj.constructor.name, state: obj.__swiftHeapObjectState }));
+            },
+            finalization: (state) => {
+                console.log(JSON.stringify({ DEBUG: true, event: "FIN", state }));
+            }
+        };
+        """
+
+    var swiftHeapObjectClassJs: String {
+        var output = ""
+        if enableLifetimeTracking {
+            output += lifetimeTrackingClassJs + "\n"
+        }
+        output += """
         const swiftHeapObjectFinalizationRegistry = (typeof FinalizationRegistry === "undefined") ? { register: () => {}, unregister: () => {} } : new FinalizationRegistry((state) => {
+
+        """
+        if enableLifetimeTracking {
+            output += "        TRACKING.finalization(state);\n"
+        }
+        output += """
             if (state.hasReleased) {
                 return;
             }
@@ -64,13 +93,25 @@ public struct BridgeJSLink {
             static __wrap(pointer, deinit, prototype) {
                 const obj = Object.create(prototype);
                 const state = { pointer, deinit, hasReleased: false };
+
+        """
+        if enableLifetimeTracking {
+            output += "        TRACKING.wrap(pointer, deinit, prototype, state);\n"
+        }
+        output += """
                 obj.pointer = pointer;
                 obj.__swiftHeapObjectState = state;
                 swiftHeapObjectFinalizationRegistry.register(obj, state, state);
                 return obj;
             }
 
             release() {
+
+        """
+        if enableLifetimeTracking {
+            output += "        TRACKING.release(this);\n"
+        }
+        output += """
                 const state = this.__swiftHeapObjectState;
                 if (state.hasReleased) {
                     return;
@@ -81,6 +122,8 @@ public struct BridgeJSLink {
             }
         }
         """
+        return output
+    }
 
     fileprivate struct LinkData {
         var exportsLines: [String] = []