Reduce copying in sending service responses.

runtime/vm/service_test.cc

 // Copyright (c) 2013, 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/globals.h"
 
 #include "include/dart_tools_api.h"
 #include "vm/dart_api_impl.h"
 #include "vm/dart_entry.h"
 #include "vm/debugger.h"
 #include "vm/globals.h"
 #include "vm/message_handler.h"
 #include "vm/object_id_ring.h"
 #include "vm/os.h"
 #include "vm/port.h"
+#include "vm/safepoint.h"
 #include "vm/service.h"
 #include "vm/unit_test.h"
 
 namespace dart {
 
 // This flag is used in the Service_Flags test below.
 DEFINE_FLAG(bool, service_testing_flag, false, "Comment");
 
 #ifndef PRODUCT
 
 class ServiceTestMessageHandler : public MessageHandler {
  public:
   ServiceTestMessageHandler() : _msg(NULL) {}
 
   ~ServiceTestMessageHandler() {
     free(_msg);
   }
 
   MessageStatus HandleMessage(Message* message) {
     if (_msg != NULL) {
       free(_msg);
     }
 
     // Parse the message.
-    String& response = String::Handle();
     Object& response_obj = Object::Handle();
     if (message->IsRaw()) {
       response_obj = message->raw_obj();
     } else {
       Thread* thread = Thread::Current();
       MessageSnapshotReader reader(message->data(), message->len(), thread);
       response_obj = reader.ReadObject();
     }
-    response ^= response_obj.raw();
-    _msg = strdup(response.ToCString());
+    if (response_obj.IsString()) {
+      String& response = String::Handle();
+      response ^= response_obj.raw();
+      _msg = strdup(response.ToCString());
+    } else {
+      ASSERT(response_obj.IsArray());
+      Array& response_array = Array::Handle();
+      response_array ^= response_obj.raw();
+      ASSERT(response_array.Length() == 1);
+      ExternalTypedData& response = ExternalTypedData::Handle();
+      response ^= response_array.At(0);
+      _msg = strdup(reinterpret_cast<char*>(response.DataAddr(0)));
+    }
+
     return kOK;
   }
 
   const char* msg() const { return _msg; }
 
   virtual Isolate* isolate() const { return Isolate::Current(); }
 
  private:
   char* _msg;
 };
@@ skipping 47 matching lines @@
 
 
 static RawClass* GetClass(const Library& lib, const char* name) {
   const Class& cls = Class::Handle(
       lib.LookupClass(String::Handle(Symbols::New(Thread::Current(), name))));
   EXPECT(!cls.IsNull());  // No ambiguity error expected.
   return cls.raw();
 }
 
 
+static void HandleIsolateMessage(Isolate* isolate, const Array& msg) {
+  TransitionNativeToVM transition(Thread::Current());
+  Service::HandleIsolateMessage(isolate, msg);
+}
+
+
+static void HandleRootMessage(const Array& message) {
+  TransitionNativeToVM transition(Thread::Current());
+  Service::HandleRootMessage(message);
+}
+
+
 TEST_CASE(Service_IsolateStickyError) {
   const char* kScript =
       "main() => throw 'HI THERE STICKY';\n";
 
   Isolate* isolate = thread->isolate();
   isolate->set_is_runnable(true);
   Dart_Handle lib = TestCase::LoadTestScript(kScript, NULL);
   EXPECT_VALID(lib);
   Library& vmlib = Library::Handle();
   vmlib ^= Api::UnwrapHandle(lib);
@@ skipping 110 matching lines @@
   Dart_Port port_id = PortMap::CreatePort(&handler);
   Dart_Handle port = Api::NewHandle(thread, SendPort::New(port_id));
   EXPECT_VALID(port);
   EXPECT_VALID(Dart_SetField(lib, NewString("port"), port));
 
   Array& service_msg = Array::Handle();
 
   // Request an invalid code object.
   service_msg =
       Eval(lib, "[0, port, '0', 'getObject', ['objectId'], ['code/0']]");
-  Service::HandleIsolateMessage(isolate, service_msg);
+  HandleIsolateMessage(isolate, service_msg);
   EXPECT_EQ(MessageHandler::kOK, handler.HandleNextMessage());
   EXPECT_SUBSTRING("\"error\"", handler.msg());
 
   // The following test checks that a code object can be found only
   // at compile_timestamp()-code.EntryPoint().
   service_msg = EvalF(lib, "[0, port, '0', 'getObject', "
                       "['objectId'], ['code/%" Px64"-%" Px "']]",
                       compile_timestamp,
                       entry);
-  Service::HandleIsolateMessage(isolate, service_msg);
+  HandleIsolateMessage(isolate, service_msg);
   EXPECT_EQ(MessageHandler::kOK, handler.HandleNextMessage());
   EXPECT_SUBSTRING("\"type\":\"Code\"", handler.msg());
   {
     // Only perform a partial match.
     const intptr_t kBufferSize = 512;
     char buffer[kBufferSize];
     OS::SNPrint(buffer, kBufferSize-1,
                 "\"fixedId\":true,\"id\":\"code\\/%" Px64 "-%" Px "\",",
                 compile_timestamp,
                 entry);
     EXPECT_SUBSTRING(buffer, handler.msg());
   }
 
   // Request code object at compile_timestamp-code.EntryPoint() + 16
   // Expect this to fail because the address is not the entry point.
   uintptr_t address = entry + 16;
   service_msg = EvalF(lib, "[0, port, '0', 'getObject', "
                       "['objectId'], ['code/%" Px64"-%" Px "']]",
                       compile_timestamp,
                       address);
-  Service::HandleIsolateMessage(isolate, service_msg);
+  HandleIsolateMessage(isolate, service_msg);
   EXPECT_EQ(MessageHandler::kOK, handler.HandleNextMessage());
   EXPECT_SUBSTRING("\"error\"", handler.msg());
 
   // Request code object at (compile_timestamp - 1)-code.EntryPoint()
   // Expect this to fail because the timestamp is wrong.
   address = entry;
   service_msg = EvalF(lib, "[0, port, '0', 'getObject', "
                       "['objectId'], ['code/%" Px64"-%" Px "']]",
                       compile_timestamp - 1,
                       address);
-  Service::HandleIsolateMessage(isolate, service_msg);
+  HandleIsolateMessage(isolate, service_msg);
   EXPECT_EQ(MessageHandler::kOK, handler.HandleNextMessage());
   EXPECT_SUBSTRING("\"error\"", handler.msg());
 
   // Request native code at address. Expect the null code object back.
   address = last;
   service_msg = EvalF(lib, "[0, port, '0', 'getObject', "
                       "['objectId'], ['code/native-%" Px "']]",
                       address);
-  Service::HandleIsolateMessage(isolate, service_msg);
+  HandleIsolateMessage(isolate, service_msg);
   EXPECT_EQ(MessageHandler::kOK, handler.HandleNextMessage());
   // TODO(turnidge): It is pretty broken to return an Instance here.  Fix.
   EXPECT_SUBSTRING("\"kind\":\"Null\"",
                    handler.msg());
 
   // Request malformed native code.
   service_msg = EvalF(lib, "[0, port, '0', 'getObject', ['objectId'], "
                       "['code/native%" Px "']]",
                       address);
-  Service::HandleIsolateMessage(isolate, service_msg);
+  HandleIsolateMessage(isolate, service_msg);
   EXPECT_EQ(MessageHandler::kOK, handler.HandleNextMessage());
   EXPECT_SUBSTRING("\"error\"", handler.msg());
 }
 
 
 TEST_CASE(Service_TokenStream) {
   const char* kScript =
       "var port;\n"  // Set to our mock port by C++.
       "\n"
       "main() {\n"
@@ skipping 22 matching lines @@
   Dart_Port port_id = PortMap::CreatePort(&handler);
   Dart_Handle port = Api::NewHandle(thread, SendPort::New(port_id));
   EXPECT_VALID(port);
   EXPECT_VALID(Dart_SetField(lib, NewString("port"), port));
 
   Array& service_msg = Array::Handle();
 
   // Fetch object.
   service_msg = EvalF(lib, "[0, port, '0', 'getObject', "
                       "['objectId'], ['objects/%" Pd "']]", id);
-  Service::HandleIsolateMessage(isolate, service_msg);
+  HandleIsolateMessage(isolate, service_msg);
   EXPECT_EQ(MessageHandler::kOK, handler.HandleNextMessage());
 
   // Check type.
   EXPECT_SUBSTRING("\"type\":\"Object\"", handler.msg());
   EXPECT_SUBSTRING("\"_vmType\":\"TokenStream\"", handler.msg());
   // Check for members array.
   EXPECT_SUBSTRING("\"members\":[", handler.msg());
 }
 
 
@@ skipping 42 matching lines @@
   Dart_Port port_id = PortMap::CreatePort(&handler);
   Dart_Handle port = Api::NewHandle(thread, SendPort::New(port_id));
   EXPECT_VALID(port);
   EXPECT_VALID(Dart_SetField(lib, NewString("port"), port));
 
   Array& service_msg = Array::Handle();
 
   // Fetch object.
   service_msg = EvalF(lib, "[0, port, '0', 'getObject', "
                       "['objectId'], ['objects/%" Pd "']]", id);
-  Service::HandleIsolateMessage(isolate, service_msg);
+  HandleIsolateMessage(isolate, service_msg);
   EXPECT_EQ(MessageHandler::kOK, handler.HandleNextMessage());
   // Check type.
   EXPECT_SUBSTRING("\"type\":\"Object\"", handler.msg());
   EXPECT_SUBSTRING("\"_vmType\":\"PcDescriptors\"", handler.msg());
   // Check for members array.
   EXPECT_SUBSTRING("\"members\":[", handler.msg());
 }
 
 
 TEST_CASE(Service_LocalVarDescriptors) {
@@ skipping 41 matching lines @@
   Dart_Port port_id = PortMap::CreatePort(&handler);
   Dart_Handle port = Api::NewHandle(thread, SendPort::New(port_id));
   EXPECT_VALID(port);
   EXPECT_VALID(Dart_SetField(lib, NewString("port"), port));
 
   Array& service_msg = Array::Handle();
 
   // Fetch object.
   service_msg = EvalF(lib, "[0, port, '0', 'getObject', "
                       "['objectId'], ['objects/%" Pd "']]", id);
-  Service::HandleIsolateMessage(isolate, service_msg);
+  HandleIsolateMessage(isolate, service_msg);
   EXPECT_EQ(MessageHandler::kOK, handler.HandleNextMessage());
   // Check type.
   EXPECT_SUBSTRING("\"type\":\"Object\"", handler.msg());
   EXPECT_SUBSTRING("\"_vmType\":\"LocalVarDescriptors\"", handler.msg());
   // Check for members array.
   EXPECT_SUBSTRING("\"members\":[", handler.msg());
 }
 
 
 
@@ skipping 39 matching lines @@
   ServiceTestMessageHandler handler;
   Dart_Port port_id = PortMap::CreatePort(&handler);
   Dart_Handle port = Api::NewHandle(thread, SendPort::New(port_id));
   EXPECT_VALID(port);
   EXPECT_VALID(Dart_SetField(lib, NewString("port"), port));
 
   Array& service_msg = Array::Handle();
 
   // Get persistent handles.
   service_msg = Eval(lib, "[0, port, '0', '_getPersistentHandles', [], []]");
-  Service::HandleIsolateMessage(isolate, service_msg);
+  HandleIsolateMessage(isolate, service_msg);
   EXPECT_EQ(MessageHandler::kOK, handler.HandleNextMessage());
   // Look for a heart beat.
   EXPECT_SUBSTRING("\"type\":\"_PersistentHandles\"", handler.msg());
   EXPECT_SUBSTRING("\"peer\":\"0xdeadbeef\"", handler.msg());
   EXPECT_SUBSTRING("\"name\":\"A\"", handler.msg());
   EXPECT_SUBSTRING("\"externalSize\":\"128\"", handler.msg());
 
   // Delete persistent handles.
   Dart_DeletePersistentHandle(persistent_handle);
   Dart_DeleteWeakPersistentHandle(Dart_CurrentIsolate(),
                                   weak_persistent_handle);
 
   // Get persistent handles (again).
   service_msg = Eval(lib, "[0, port, '0', '_getPersistentHandles', [], []]");
-  Service::HandleIsolateMessage(isolate, service_msg);
+  HandleIsolateMessage(isolate, service_msg);
   EXPECT_EQ(MessageHandler::kOK, handler.HandleNextMessage());
   EXPECT_SUBSTRING("\"type\":\"_PersistentHandles\"", handler.msg());
   // Verify that old persistent handles are not present.
   EXPECT_NOTSUBSTRING("\"peer\":\"0xdeadbeef\"", handler.msg());
   EXPECT_NOTSUBSTRING("\"name\":\"A\"", handler.msg());
   EXPECT_NOTSUBSTRING("\"externalSize\":\"128\"", handler.msg());
 }
 
 
 TEST_CASE(Service_Address) {
@@ skipping 25 matching lines @@
     char buf[1024];
     bool ref = offset % 2 == 0;
     OS::SNPrint(buf, sizeof(buf),
                 (ref
                  ? "[0, port, '0', '_getObjectByAddress', "
                    "['address', 'ref'], ['%" Px "', 'true']]"
                  : "[0, port, '0', '_getObjectByAddress', "
                    "['address'], ['%" Px "']]"),
                 addr);
     service_msg = Eval(lib, buf);
-    Service::HandleIsolateMessage(isolate, service_msg);
+    HandleIsolateMessage(isolate, service_msg);
     EXPECT_EQ(MessageHandler::kOK, handler.HandleNextMessage());
     EXPECT_SUBSTRING(ref ? "\"type\":\"@Instance\"" :
                            "\"type\":\"Instance\"",
                      handler.msg());
     EXPECT_SUBSTRING("\"kind\":\"String\"", handler.msg());
     EXPECT_SUBSTRING("foobar", handler.msg());
   }
   // Expect null when no object is found.
   service_msg = Eval(lib, "[0, port, '0', '_getObjectByAddress', "
                      "['address'], ['7']]");
-  Service::HandleIsolateMessage(isolate, service_msg);
+  HandleIsolateMessage(isolate, service_msg);
   EXPECT_EQ(MessageHandler::kOK, handler.HandleNextMessage());
   // TODO(turnidge): Should this be a ServiceException instead?
   EXPECT_SUBSTRING("{\"type\":\"Sentinel\",\"kind\":\"Free\","
                    "\"valueAsString\":\"<free>\"",
                handler.msg());
 }
 
 
 static bool alpha_callback(
     const char* name,
@@ skipping 40 matching lines @@
   // Build a mock message handler and wrap it in a dart port.
   ServiceTestMessageHandler handler;
   Dart_Port port_id = PortMap::CreatePort(&handler);
   Dart_Handle port = Api::NewHandle(thread, SendPort::New(port_id));
   EXPECT_VALID(port);
   EXPECT_VALID(Dart_SetField(lib, NewString("port"), port));
 
 
   Array& service_msg = Array::Handle();
   service_msg = Eval(lib, "[0, port, '\"', 'alpha', [], []]");
-  Service::HandleRootMessage(service_msg);
+  HandleRootMessage(service_msg);
   EXPECT_EQ(MessageHandler::kOK, handler.HandleNextMessage());
   EXPECT_STREQ("{\"jsonrpc\":\"2.0\", \"result\":alpha,\"id\":\"\\\"\"}",
                handler.msg());
   service_msg = Eval(lib, "[0, port, 1, 'beta', [], []]");
-  Service::HandleRootMessage(service_msg);
+  HandleRootMessage(service_msg);
   EXPECT_EQ(MessageHandler::kOK, handler.HandleNextMessage());
   EXPECT_STREQ("{\"jsonrpc\":\"2.0\", \"error\":beta,\"id\":1}",
                handler.msg());
 }
 
 
 TEST_CASE(Service_EmbedderIsolateHandler) {
   const char* kScript =
     "var port;\n"  // Set to our mock port by C++.
     "\n"
@@ skipping 14 matching lines @@
 
   // Build a mock message handler and wrap it in a dart port.
   ServiceTestMessageHandler handler;
   Dart_Port port_id = PortMap::CreatePort(&handler);
   Dart_Handle port = Api::NewHandle(thread, SendPort::New(port_id));
   EXPECT_VALID(port);
   EXPECT_VALID(Dart_SetField(lib, NewString("port"), port));
 
   Array& service_msg = Array::Handle();
   service_msg = Eval(lib, "[0, port, '0', 'alpha', [], []]");
-  Service::HandleIsolateMessage(isolate, service_msg);
+  HandleIsolateMessage(isolate, service_msg);
   EXPECT_EQ(MessageHandler::kOK, handler.HandleNextMessage());
   EXPECT_STREQ("{\"jsonrpc\":\"2.0\", \"result\":alpha,\"id\":\"0\"}",
                handler.msg());
   service_msg = Eval(lib, "[0, port, '0', 'beta', [], []]");
-  Service::HandleIsolateMessage(isolate, service_msg);
+  HandleIsolateMessage(isolate, service_msg);
   EXPECT_EQ(MessageHandler::kOK, handler.HandleNextMessage());
   EXPECT_STREQ("{\"jsonrpc\":\"2.0\", \"error\":beta,\"id\":\"0\"}",
                handler.msg());
 }
 
 // TODO(zra): Remove when tests are ready to enable.
 #if !defined(TARGET_ARCH_ARM64)
 
 TEST_CASE(Service_Profile) {
   const char* kScript =
@@ skipping 14 matching lines @@
 
   // Build a mock message handler and wrap it in a dart port.
   ServiceTestMessageHandler handler;
   Dart_Port port_id = PortMap::CreatePort(&handler);
   Dart_Handle port = Api::NewHandle(thread, SendPort::New(port_id));
   EXPECT_VALID(port);
   EXPECT_VALID(Dart_SetField(lib, NewString("port"), port));
 
   Array& service_msg = Array::Handle();
   service_msg = Eval(lib, "[0, port, '0', '_getCpuProfile', [], []]");
-  Service::HandleIsolateMessage(isolate, service_msg);
+  HandleIsolateMessage(isolate, service_msg);
   EXPECT_EQ(MessageHandler::kOK, handler.HandleNextMessage());
   // Expect error (tags required).
   EXPECT_SUBSTRING("\"error\"", handler.msg());
 
   service_msg =
       Eval(lib, "[0, port, '0', '_getCpuProfile', ['tags'], ['None']]");
-  Service::HandleIsolateMessage(isolate, service_msg);
+  HandleIsolateMessage(isolate, service_msg);
   EXPECT_EQ(MessageHandler::kOK, handler.HandleNextMessage());
   // Expect profile
   EXPECT_SUBSTRING("\"type\":\"_CpuProfile\"", handler.msg());
 
   service_msg =
       Eval(lib, "[0, port, '0', '_getCpuProfile', ['tags'], ['Bogus']]");
-  Service::HandleIsolateMessage(isolate, service_msg);
+  HandleIsolateMessage(isolate, service_msg);
   EXPECT_EQ(MessageHandler::kOK, handler.HandleNextMessage());
   // Expect error.
   EXPECT_SUBSTRING("\"error\"", handler.msg());
 }
 
 #endif  // !defined(TARGET_ARCH_ARM64)
 
 #endif  // !PRODUCT
 
 }  // namespace dart