inspector: use inspector API for "break on start"

This change removes a need for using deprecated debug context for
breaking at the start of the main module.

PR-URL: https://github.com/nodejs/node/pull/12076
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

lib/internal/bootstrap_node.js

@@ -262,7 +262,9 @@
     if (process.inspector) {
       inspectorConsole = global.console;
       wrapConsoleCall = process.inspector.wrapConsoleCall;
-      delete process.inspector;
+      delete process.inspector.wrapConsoleCall;
+      if (Object.keys(process.inspector).length === 0)
+        delete process.inspector;
     }
     var console;
     Object.defineProperty(global, 'console', {

lib/module.js

@@ -472,6 +472,19 @@ function tryModuleLoad(module, filename) {
   }
 }
 
+function getInspectorCallWrapper() {
+  var inspector = process.inspector;
+  if (!inspector || !inspector.callAndPauseOnStart) {
+    return null;
+  }
+  var wrapper = inspector.callAndPauseOnStart.bind(inspector);
+  delete inspector.callAndPauseOnStart;
+  if (Object.keys(process.inspector).length === 0) {
+    delete process.inspector;
+  }
+  return wrapper;
+}
+
 Module._resolveFilename = function(request, parent, isMain) {
   if (NativeModule.nonInternalExists(request)) {
     return request;
@@ -561,6 +574,7 @@ Module.prototype._compile = function(content, filename) {
     displayErrors: true
   });
 
+  var inspectorWrapper = null;
   if (process._debugWaitConnect && process._eval == null) {
     if (!resolvedArgv) {
       // we enter the repl if we're not given a filename argument.
@@ -574,16 +588,25 @@ Module.prototype._compile = function(content, filename) {
     // Set breakpoint on module start
     if (filename === resolvedArgv) {
       delete process._debugWaitConnect;
-      const Debug = vm.runInDebugContext('Debug');
+      inspectorWrapper = getInspectorCallWrapper();
-      Debug.setBreakPoint(compiledWrapper, 0, 0);
+      if (!inspectorWrapper) {
+        const Debug = vm.runInDebugContext('Debug');
+        Debug.setBreakPoint(compiledWrapper, 0, 0);
+      }
     }
   }
   var dirname = path.dirname(filename);
   var require = internalModule.makeRequireFunction(this);
   var depth = internalModule.requireDepth;
   if (depth === 0) stat.cache = new Map();
-  var result = compiledWrapper.call(this.exports, this.exports, require, this,
+  var result;
-                                    filename, dirname);
+  if (inspectorWrapper) {
+    result = inspectorWrapper(compiledWrapper, this.exports, this.exports,
+                              require, this, filename, dirname);
+  } else {
+    result = compiledWrapper.call(this.exports, this.exports, require, this,
+                                  filename, dirname);
+  }
   if (depth === 0) stat.cache = null;
   return result;
 };

src/inspector_agent.cc

@@ -94,7 +94,6 @@ std::unique_ptr<StringBuffer> Utf8ToStringView(const std::string& message) {
                   utf16.length());
   return StringBuffer::create(view);
 }
-
 }  // namespace
 
 class V8NodeInspector;
@@ -145,6 +144,8 @@ class AgentImpl {
   void FatalException(v8::Local<v8::Value> error,
                       v8::Local<v8::Message> message);
 
+  void SchedulePauseOnNextStatement(const std::string& reason);
+
   void PostIncomingMessage(InspectorAction action, int session_id,
                            const std::string& message);
   void ResumeStartup() {
@@ -160,6 +161,8 @@ class AgentImpl {
   static void ThreadCbIO(void* agent);
   static void WriteCbIO(uv_async_t* async);
   static void MainThreadAsyncCb(uv_async_t* req);
+  static void CallAndPauseOnStart(
+      const v8::FunctionCallbackInfo<v8::Value>& args);
 
   void InstallInspectorOnProcess();
 
@@ -310,6 +313,14 @@ class V8NodeInspector : public v8_inspector::V8InspectorClient {
     session_->dispatchProtocolMessage(message);
   }
 
+  void schedulePauseOnNextStatement(const std::string& reason) {
+    if (session_ != nullptr) {
+      std::unique_ptr<StringBuffer> buffer = Utf8ToStringView(reason);
+      session_->schedulePauseOnNextStatement(buffer->string(),
+                                             buffer->string());
+    }
+  }
+
   v8::Local<v8::Context> ensureDefaultContextInGroup(int contextGroupId)
       override {
     return env_->context();
@@ -477,6 +488,28 @@ void AgentImpl::InstallInspectorOnProcess() {
   v8::Local<v8::Object> inspector = v8::Object::New(env->isolate());
   READONLY_PROPERTY(process, "inspector", inspector);
   env->SetMethod(inspector, "wrapConsoleCall", InspectorWrapConsoleCall);
+  if (options_.wait_for_connect()) {
+    env->SetMethod(inspector, "callAndPauseOnStart", CallAndPauseOnStart);
+  }
+}
+
+// static
+void AgentImpl::CallAndPauseOnStart(
+      const v8::FunctionCallbackInfo<v8::Value>& args) {
+  Environment* env = Environment::GetCurrent(args);
+  CHECK_GT(args.Length(), 1);
+  CHECK(args[0]->IsFunction());
+  std::vector<v8::Local<v8::Value>> call_args;
+  for (int i = 2; i < args.Length(); i++) {
+    call_args.push_back(args[i]);
+  }
+
+  env->inspector_agent()->SchedulePauseOnNextStatement("Break on start");
+
+  v8::MaybeLocal<v8::Value> retval =
+      args[0].As<v8::Function>()->Call(env->context(), args[1],
+                                       call_args.size(), call_args.data());
+  args.GetReturnValue().Set(retval.ToLocalChecked());
 }
 
 std::unique_ptr<StringBuffer> ToProtocolString(v8::Local<v8::Value> value) {
@@ -682,6 +715,10 @@ void AgentImpl::Write(TransportAction action, int session_id,
   CHECK_EQ(0, err);
 }
 
+void AgentImpl::SchedulePauseOnNextStatement(const std::string& reason) {
+  inspector_->schedulePauseOnNextStatement(reason);
+}
+
 // Exported class Agent
 Agent::Agent(node::Environment* env) : impl(new AgentImpl(env)) {}
 
@@ -715,6 +752,10 @@ void Agent::FatalException(v8::Local<v8::Value> error,
   impl->FatalException(error, message);
 }
 
+void Agent::SchedulePauseOnNextStatement(const std::string& reason) {
+  impl->SchedulePauseOnNextStatement(reason);
+}
+
 InspectorAgentDelegate::InspectorAgentDelegate(AgentImpl* agent,
                                                const std::string& script_path,
                                                const std::string& script_name,

src/inspector_agent.h

@@ -43,6 +43,7 @@ class Agent {
   void WaitForDisconnect();
   void FatalException(v8::Local<v8::Value> error,
                       v8::Local<v8::Message> message);
+  void SchedulePauseOnNextStatement(const std::string& reason);
  private:
   AgentImpl* impl;
 };