feat(inspector): attach Chrome DevTools to Web Worker isolates (#386)

Author: edusperoni

NativeScript/inspector/JsV8InspectorClient.h

@@ -5,6 +5,7 @@
 
 #include <functional>
 #include <map>
+#include <mutex>
 #include <string>
 #include <vector>
 
@@ -15,6 +16,8 @@
 
 namespace v8_inspector {
 
+class WorkerInspectorClient;
+
 class JsV8InspectorClient : V8InspectorClient, V8Inspector::Channel {
  public:
   JsV8InspectorClient(tns::Runtime* runtime);
@@ -23,6 +26,20 @@ class JsV8InspectorClient : V8InspectorClient, V8Inspector::Channel {
   void disconnect();
   void dispatchMessage(const std::string& message);
 
+  // The single instance debugging the main isolate (created when IsDebug);
+  // also acts as the router for worker sessions. Null in release builds.
+  static JsV8InspectorClient* GetInstance();
+
+  // Thread-safe write to the connected frontend (no-op when disconnected).
+  void SendToFrontend(const std::string& message);
+
+  // Worker targets (Chrome DevTools Target domain, flat-session mode).
+  // Register/Unregister are called on the worker's own thread.
+  void RegisterWorkerTarget(int workerId, WorkerInspectorClient* client);
+  void UnregisterWorkerTarget(int workerId);
+  // Called on a worker thread by the Debugger.pause interrupt.
+  void SchedulePauseInWorker(int workerId);
+
   // Overrides of V8Inspector::Channel
   void sendResponse(int callId, std::unique_ptr<StringBuffer> message) override;
   void sendNotification(std::unique_ptr<StringBuffer> message) override;
@@ -63,13 +80,39 @@ class JsV8InspectorClient : V8InspectorClient, V8Inspector::Channel {
 
   // Streams backing Network.loadNetworkResource responses, read by the
   // frontend through IO.read/IO.close (how Chrome DevTools fetches source
-  // maps from the target). Only touched from dispatchMessage (main thread).
+  // maps from the target). Served on the socket thread for any session;
+  // guarded by resourceStreamsMutex_.
   struct ResourceStream {
     std::string data;
     size_t offset = 0;
   };
   std::map<std::string, ResourceStream> resourceStreams_;
   int lastStreamId_ = 0;
+  std::mutex resourceStreamsMutex_;
+
+  // Worker targets announced to the frontend via Target.attachedToTarget,
+  // keyed by their flat-protocol sessionId. Guarded by workerTargetsMutex_;
+  // a registered client pointer stays valid until UnregisterWorkerTarget
+  // (which runs on the worker's own thread, before the client is deleted).
+  struct WorkerTarget {
+    int workerId;
+    WorkerInspectorClient* client;
+    bool announced = false;
+  };
+  std::map<std::string, WorkerTarget> workerTargets_;
+  std::mutex workerTargetsMutex_;
+  bool autoAttach_ = false;  // guarded by workerTargetsMutex_
+
+  static JsV8InspectorClient* instance_;
+
+  std::mutex senderMutex_;
+
+  // Routes a frontend message carrying a sessionId to its worker session
+  // (socket thread). msgId is -1 when the message has no id.
+  void RouteToWorker(const std::string& sessionId, const std::string& method,
+                     long long msgId, const std::string& message);
+  // Announces all not-yet-announced workers (after Target.setAutoAttach).
+  void AnnounceWorkerTargets();
 
   // Override of V8InspectorClient
   v8::Local<v8::Context> ensureDefaultContextInGroup(
@@ -90,10 +133,15 @@ class JsV8InspectorClient : V8InspectorClient, V8Inspector::Channel {
       const v8::FunctionCallbackInfo<v8::Value>& args);
 
   // Source map delivery to Chrome DevTools (Network.loadNetworkResource + IO
-  // domain). V8's inspector doesn't implement these embedder domains.
-  void HandleLoadNetworkResource(int msgId, const std::string& url);
-  void HandleIORead(int msgId, const std::string& handle, int size);
-  void HandleIOClose(int msgId, const std::string& handle);
+  // domain). V8's inspector doesn't implement these embedder domains. The
+  // handlers are filesystem-only and thread-safe; they serve any session
+  // (sessionId is echoed in the reply when non-empty).
+  void HandleLoadNetworkResource(int msgId, const std::string& url,
+                                 const std::string& sessionId);
+  void HandleIORead(int msgId, const std::string& handle, int size,
+                    const std::string& sessionId);
+  void HandleIOClose(int msgId, const std::string& handle,
+                     const std::string& sessionId);
 
   // {N} specific helpers
   bool CallDomainHandlerFunction(v8::Local<v8::Context> context,