Make v8::TryCatch able to consume natively thrown exceptions (again).

R=yangguo@chromium.org
BUG=chromium:362388
TEST=cctest/test-api/TryCatchNative
LOG=N

Review URL: https://codereview.chromium.org/291393002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21456 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/api.cc

@@ -1830,6 +1830,12 @@ v8::TryCatch::~TryCatch() {
     reinterpret_cast<Isolate*>(isolate_)->ThrowException(exc);
     ASSERT(!isolate_->thread_local_top()->rethrowing_message_);
   } else {
+    if (HasCaught() && isolate_->has_scheduled_exception()) {
+      // If an exception was caught but is still scheduled because no API call
+      // promoted it, then it is canceled to prevent it from being propagated.
+      // Note that this will not cancel termination exceptions.
+      isolate_->CancelScheduledExceptionFromTryCatch(this);
+    }
     isolate_->UnregisterTryCatchHandler(this);
     v8::internal::SimulatorStack::UnregisterCTryCatch();
   }

src/isolate.cc

@@ -908,6 +908,15 @@ void Isolate::RestorePendingMessageFromTryCatch(v8::TryCatch* handler) {
 }
 
 
+void Isolate::CancelScheduledExceptionFromTryCatch(v8::TryCatch* handler) {
+  ASSERT(has_scheduled_exception());
+  if (scheduled_exception() == handler->exception_) {
+    ASSERT(scheduled_exception() != heap()->termination_exception());
+    clear_scheduled_exception();
+  }
+}
+
+
 Object* Isolate::PromoteScheduledException() {
   Object* thrown = scheduled_exception();
   clear_scheduled_exception();
@@ -1213,8 +1222,7 @@ void Isolate::ReportPendingMessages() {
   PropagatePendingExceptionToExternalTryCatch();
 
   HandleScope scope(this);
-  if (thread_local_top_.pending_exception_ ==
-          heap()->termination_exception()) {
+  if (thread_local_top_.pending_exception_ == heap()->termination_exception()) {
     // Do nothing: if needed, the exception has been already propagated to
     // v8::TryCatch.
   } else {
@@ -1751,8 +1759,7 @@ void Isolate::PropagatePendingExceptionToExternalTryCatch() {
 
   if (!external_caught) return;
 
-  if (thread_local_top_.pending_exception_ ==
-             heap()->termination_exception()) {
+  if (thread_local_top_.pending_exception_ == heap()->termination_exception()) {
     try_catch_handler()->can_continue_ = false;
     try_catch_handler()->has_terminated_ = true;
     try_catch_handler()->exception_ = heap()->null_value();

src/isolate.h

@@ -735,6 +735,8 @@ class Isolate {
   // Re-set pending message, script and positions reported to the TryCatch
   // back to the TLS for re-use when rethrowing.
   void RestorePendingMessageFromTryCatch(v8::TryCatch* handler);
+  // Un-schedule an exception that was caught by a TryCatch handler.
+  void CancelScheduledExceptionFromTryCatch(v8::TryCatch* handler);
   void ReportPendingMessages();
   // Return pending location if any or unfilled structure.
   MessageLocation GetMessageLocation();

test/cctest/test-api.cc

@@ -5343,15 +5343,28 @@ THREADED_TEST(TryCatchAndFinally) {
 }
 
 
-static void TryCatchNestedHelper(int depth) {
+static void TryCatchNested1Helper(int depth) {
   if (depth > 0) {
     v8::TryCatch try_catch;
     try_catch.SetVerbose(true);
-    TryCatchNestedHelper(depth - 1);
+    TryCatchNested1Helper(depth - 1);
     CHECK(try_catch.HasCaught());
     try_catch.ReThrow();
   } else {
-    CcTest::isolate()->ThrowException(v8_str("back"));
+    CcTest::isolate()->ThrowException(v8_str("E1"));
+  }
+}
+
+
+static void TryCatchNested2Helper(int depth) {
+  if (depth > 0) {
+    v8::TryCatch try_catch;
+    try_catch.SetVerbose(true);
+    TryCatchNested2Helper(depth - 1);
+    CHECK(try_catch.HasCaught());
+    try_catch.ReThrow();
+  } else {
+    CompileRun("throw 'E2';");
   }
 }
 
@@ -5360,10 +5373,22 @@ TEST(TryCatchNested) {
   v8::V8::Initialize();
   LocalContext context;
   v8::HandleScope scope(context->GetIsolate());
-  v8::TryCatch try_catch;
-  TryCatchNestedHelper(5);
-  CHECK(try_catch.HasCaught());
-  CHECK_EQ(0, strcmp(*v8::String::Utf8Value(try_catch.Exception()), "back"));
+
+  {
+    // Test nested try-catch with a native throw in the end.
+    v8::TryCatch try_catch;
+    TryCatchNested1Helper(5);
+    CHECK(try_catch.HasCaught());
+    CHECK_EQ(0, strcmp(*v8::String::Utf8Value(try_catch.Exception()), "E1"));
+  }
+
+  {
+    // Test nested try-catch with a JavaScript throw in the end.
+    v8::TryCatch try_catch;
+    TryCatchNested2Helper(5);
+    CHECK(try_catch.HasCaught());
+    CHECK_EQ(0, strcmp(*v8::String::Utf8Value(try_catch.Exception()), "E2"));
+  }
 }
 
 
@@ -5409,6 +5434,28 @@ TEST(TryCatchMixedNesting) {
 }
 
 
+void TryCatchNativeHelper(const v8::FunctionCallbackInfo<v8::Value>& args) {
+  ApiTestFuzzer::Fuzz();
+  v8::TryCatch try_catch;
+  args.GetIsolate()->ThrowException(v8_str("boom"));
+  CHECK(try_catch.HasCaught());
+}
+
+
+TEST(TryCatchNative) {
+  v8::Isolate* isolate = CcTest::isolate();
+  v8::HandleScope scope(isolate);
+  v8::V8::Initialize();
+  v8::TryCatch try_catch;
+  Local<ObjectTemplate> templ = ObjectTemplate::New(isolate);
+  templ->Set(v8_str("TryCatchNativeHelper"),
+             v8::FunctionTemplate::New(isolate, TryCatchNativeHelper));
+  LocalContext context(0, templ);
+  CompileRun("TryCatchNativeHelper();");
+  CHECK(!try_catch.HasCaught());
+}
+
+
 THREADED_TEST(Equality) {
   LocalContext context;
   v8::Isolate* isolate = context->GetIsolate();