Second version of support for specifying an unhandled exception callback

runtime/lib/isolate.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "platform/assert.h"
 #include "vm/bootstrap_natives.h"
 #include "vm/class_finalizer.h"
 #include "vm/dart.h"
 #include "vm/dart_api_impl.h"
 #include "vm/dart_entry.h"
@@ skipping 184 matching lines @@
     *error = zone->PrintToString("Unable to canonicalize uri '%s': "
                                  "library tag handler returned wrong type",
                                  uri.ToCString());
     return false;
   }
 }
 
 
 class SpawnState {
  public:
-  explicit SpawnState(const Function& func)
+  explicit SpawnState(const Function& func, const Function& callback_func)
       : isolate_(NULL),
         script_url_(NULL),
         library_url_(NULL),
-        function_name_(NULL) {
+        function_name_(NULL),
+        exception_callback_name_(NULL) {
     script_url_ = strdup(GetRootScriptUri(Isolate::Current()));
     const Class& cls = Class::Handle(func.Owner());
     ASSERT(cls.IsTopLevel());
     const Library& lib = Library::Handle(cls.library());
     const String& lib_url = String::Handle(lib.url());
     library_url_ = strdup(lib_url.ToCString());
 
     const String& func_name = String::Handle(func.name());
     function_name_ = strdup(func_name.ToCString());
+    if (!callback_func.IsNull()) {
+      const String& callback_name = String::Handle(callback_func.name());
+      exception_callback_name_ = strdup(callback_name.ToCString());
+    } else {
+      exception_callback_name_ = strdup("_unhandledExceptionCallback");
+    }
   }
 
   explicit SpawnState(const char* script_url)
       : isolate_(NULL),
         library_url_(NULL),
         function_name_(NULL) {
     script_url_ = strdup(script_url);
     library_url_ = NULL;
     function_name_ = strdup("main");
+    exception_callback_name_ = strdup("_unhandledExceptionCallback");
   }
 
   ~SpawnState() {
     free(script_url_);
     free(library_url_);
     free(function_name_);
+    if (exception_callback_name_ != NULL) {
+      free(exception_callback_name_);
+    }
   }
 
   Isolate* isolate() const { return isolate_; }
   void set_isolate(Isolate* value) { isolate_ = value; }
   char* script_url() const { return script_url_; }
   char* library_url() const { return library_url_; }
   char* function_name() const { return function_name_; }
+  char* exception_callback_name() const { return exception_callback_name_; }
 
   RawObject* ResolveFunction() {
     // Resolve the library.
     Library& lib = Library::Handle();
     if (library_url()) {
       const String& lib_url = String::Handle(String::New(library_url()));
       lib = Library::LookupLibrary(lib_url);
       if (lib.IsNull() || lib.IsError()) {
         const String& msg = String::Handle(String::NewFormatted(
             "Unable to find library '%s'.", library_url()));
@@ skipping 20 matching lines @@
   void Cleanup() {
     SwitchIsolateScope switch_scope(isolate());
     Dart::ShutdownIsolate();
   }
 
  private:
   Isolate* isolate_;
   char* script_url_;
   char* library_url_;
   char* function_name_;
+  char* exception_callback_name_;
 };
 
 
 static bool CreateIsolate(SpawnState* state, char** error) {
   Isolate* parent_isolate = Isolate::Current();
 
   Dart_IsolateCreateCallback callback = Isolate::CreateCallback();
   if (callback == NULL) {
     *error = strdup("Null callback specified for isolate creation\n");
     Isolate::SetCurrent(parent_isolate);
@@ skipping 22 matching lines @@
   {
     StackZone zone(child_isolate);
     HandleScope handle_scope(child_isolate);
     const Object& result = Object::Handle(state->ResolveFunction());
     if (result.IsError()) {
       Error& errobj = Error::Handle();
       errobj ^= result.raw();
       *error = strdup(errobj.ToErrorCString());
       resolve_error = true;
     }
+
+    if (!resolve_error) {
+      StackZone zone(child_isolate);
+      HandleScope handle_scope(child_isolate);
+      RawString* raw_name = String::New(state->exception_callback_name());
+      const String& callback_name = String::Handle(child_isolate, raw_name);
+      child_isolate->object_store()->
+          set_unhandled_exception_handler(callback_name);
+    }
   }
   if (resolve_error) {
     Dart::ShutdownIsolate();
     Isolate::SetCurrent(parent_isolate);
     return false;
   }
 
   Isolate::SetCurrent(parent_isolate);
   return true;
 }
 
 
 static bool RunIsolate(uword parameter) {
   Isolate* isolate = reinterpret_cast<Isolate*>(parameter);
   SpawnState* state = reinterpret_cast<SpawnState*>(isolate->spawn_data());
   isolate->set_spawn_data(0);
   {
     StartIsolateScope start_scope(isolate);
     StackZone zone(isolate);
     HandleScope handle_scope(isolate);
     if (!ClassFinalizer::FinalizePendingClasses()) {
       // Error is in sticky error already.
       return false;
     }
+
     Object& result = Object::Handle();
-
     result = state->ResolveFunction();
     delete state;
     state = NULL;
     if (result.IsError()) {
       StoreError(isolate, result);
       return false;
     }
     ASSERT(result.IsFunction());
     Function& func = Function::Handle(isolate);
     func ^= result.raw();
@@ skipping 31 matching lines @@
   // Start the new isolate.
   state->isolate()->set_spawn_data(reinterpret_cast<uword>(state));
   state->isolate()->message_handler()->Run(
       Dart::thread_pool(), RunIsolate, ShutdownIsolate,
       reinterpret_cast<uword>(state->isolate()));
 
   return port.raw();
 }
 
 
-DEFINE_NATIVE_ENTRY(isolate_spawnFunction, 1) {
+DEFINE_NATIVE_ENTRY(isolate_spawnFunction, 2) {
   GET_NON_NULL_NATIVE_ARGUMENT(Instance, closure, arguments->NativeArgAt(0));
   bool throw_exception = false;
   Function& func = Function::Handle();
   if (closure.IsClosure()) {
     func ^= Closure::function(closure);
     const Class& cls = Class::Handle(func.Owner());
     if (!func.IsClosureFunction() || !func.is_static() || !cls.IsTopLevel()) {
       throw_exception = true;
     }
   } else {
     throw_exception = true;
   }
   if (throw_exception) {
     const String& msg = String::Handle(String::New(
         "spawnFunction expects to be passed a closure to a top-level static "
         "function"));
     ThrowIllegalArgException(msg);
   }
 
+  GET_NATIVE_ARGUMENT(Instance, callback, arguments->NativeArgAt(1));
+  Function& callback_func = Function::Handle();
+  if (callback.IsNull()) {
+    callback_func = Function::null();

[siva, 2012/12/13 18:30:38]

When a handle is created it is initialized with null there is no need to assign
a null again to it.
Maybe you can structure as:
if (callback.IsClosure()) {
   ...
} else if (!callback.IsNull()) {
   ...
}

[Tom Ball, 2012/12/13 19:33:22]

Fixed.

+  } else if (callback.IsClosure()) {
+    callback_func ^= Closure::function(callback);
+    const Class& cls = Class::Handle(callback_func.Owner());
+    if (!callback_func.IsClosureFunction() || !callback_func.is_static() ||
+        !cls.IsTopLevel()) {
+      throw_exception = true;
+    }
+  } else {
+    throw_exception = true;
+  }
+  if (throw_exception) {
+    const String& msg = String::Handle(String::New(
+        "spawnFunction expects to be passed either a unhandled exception "
+        "callback to a top-level static function, or null"));
+    ThrowIllegalArgException(msg);
+  }
+
 #if defined(DEBUG)
   const Context& ctx = Context::Handle(Closure::context(closure));
   ASSERT(ctx.num_variables() == 0);

[siva, 2012/12/13 18:30:38]

We need a similar assert for callback.

[Tom Ball, 2012/12/13 19:33:22]

Done.

 #endif
 
-  return Spawn(arguments, new SpawnState(func));
+  return Spawn(arguments, new SpawnState(func, callback_func));
 }
 
 
 DEFINE_NATIVE_ENTRY(isolate_spawnUri, 1) {
   GET_NON_NULL_NATIVE_ARGUMENT(String, uri, arguments->NativeArgAt(0));
 
   // Canonicalize the uri with respect to the current isolate.
   char* error = NULL;
   char* canonical_uri = NULL;
   const Library& root_lib =
@@ skipping 11 matching lines @@
 
 DEFINE_NATIVE_ENTRY(isolate_getPortInternal, 0) {
   const Object& port = Object::Handle(ReceivePortCreate(isolate->main_port()));
   if (port.IsError()) {
     Exceptions::PropagateError(Error::Cast(port));
   }
   return port.raw();
 }
 
 }  // namespace dart