Allocate a Dart_CMessage structure when decoding a message into C structures

runtime/vm/snapshot_test.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/bigint_operations.h"
 #include "vm/class_finalizer.h"
 #include "vm/dart_api_impl.h"
 #include "vm/dart_api_state.h"
 #include "vm/snapshot.h"
@@ skipping 19 matching lines @@
       dbl1 ^= expected.raw();
       dbl2 ^= actual.raw();
       return dbl1.value() == dbl2.value();
     }
     return false;
   }
   return false;
 }
 
 
-static uint8_t* allocator(uint8_t* ptr, intptr_t old_size, intptr_t new_size) {
+static uint8_t* malloc_allocator(
+    uint8_t* ptr, intptr_t old_size, intptr_t new_size) {
   return reinterpret_cast<uint8_t*>(realloc(ptr, new_size));
 }
 
 
+static uint8_t* zone_allocator(
+    uint8_t* ptr, intptr_t old_size, intptr_t new_size) {
+  Zone* zone = Isolate::Current()->current_zone();
+  return reinterpret_cast<uint8_t*>(
+      zone->Reallocate(reinterpret_cast<uword>(ptr), old_size, new_size));
+}
+
+
+static Dart_CMessage* DecodeMessage(uint8_t* message,
+                                    intptr_t length,
+                                    ReAlloc allocator) {
+  CMessageReader message_reader(message, length, allocator);
+  return message_reader.ReadMessage();
+}
+
+
 TEST_CASE(SerializeNull) {
   // Write snapshot with object content.
   uint8_t* buffer;
-  SnapshotWriter writer(Snapshot::kMessage, &buffer, &allocator);
+  SnapshotWriter writer(Snapshot::kMessage, &buffer, &malloc_allocator);
   const Object& null_object = Object::Handle();
   writer.WriteObject(null_object.raw());
   writer.FinalizeBuffer();
 
   // Create a snapshot object using the buffer.
   const Snapshot* snapshot = Snapshot::SetupFromBuffer(buffer);
 
   // Read object back from the snapshot.
   SnapshotReader reader(snapshot, Isolate::Current());
   const Object& serialized_object = Object::Handle(reader.ReadObject());
   EXPECT(Equals(null_object, serialized_object));
 
   // Read object back from the snapshot into a C structure.
-  CMessageReader mreader(buffer + Snapshot::kHeaderSize,
-                        writer.BytesWritten(),
-                        &allocator);
-  Dart_CObject* cobject = mreader.ReadObject();
+  Zone zone(Isolate::Current());
+  Dart_CMessage* cmessage = DecodeMessage(buffer + Snapshot::kHeaderSize,
+                                          writer.BytesWritten(),
+                                          &zone_allocator);
+  Dart_CObject* cobject = cmessage->root;
   EXPECT_NOTNULL(cobject);
   EXPECT_EQ(Dart_CObject::kNull, cobject->type);

[siva, 2012/02/02 03:46:45]

I think there was a leak originally in this test case, a free of 'buffer' (The
buffer into which the snapshot was written into) was not being done.
Sorry about that.

free(buffer);

would be needed in all these unit tests that invoke the SnapshotWriter.

Or we could use the new zone_allocator that you have added as the allocator for
the SnapshotWriter too and move your Zone zone(...) declaration above the writer
object.

Your choice.

[Søren Gjesse, 2012/02/02 10:49:33]

Changed to use zone allocator in all tests involving reading into Dart_CMessage.

-  free(cobject);
 }
 
 
 TEST_CASE(SerializeSmi1) {
   // Write snapshot with object content.
   uint8_t* buffer;
-  SnapshotWriter writer(Snapshot::kMessage, &buffer, &allocator);
+  SnapshotWriter writer(Snapshot::kMessage, &buffer, &malloc_allocator);
   const Smi& smi = Smi::Handle(Smi::New(124));
   writer.WriteObject(smi.raw());
   writer.FinalizeBuffer();
 
   // Create a snapshot object using the buffer.
   const Snapshot* snapshot = Snapshot::SetupFromBuffer(buffer);
 
   // Read object back from the snapshot.
   SnapshotReader reader(snapshot, Isolate::Current());
   const Object& serialized_object = Object::Handle(reader.ReadObject());
   EXPECT(Equals(smi, serialized_object));
 
   // Read object back from the snapshot into a C structure.
-  CMessageReader mreader(buffer + Snapshot::kHeaderSize,
-                         writer.BytesWritten(),
-                         &allocator);
-  Dart_CObject* cobject = mreader.ReadObject();
+  Zone zone(Isolate::Current());
+  Dart_CMessage* cmessage = DecodeMessage(buffer + Snapshot::kHeaderSize,
+                                          writer.BytesWritten(),
+                                          &zone_allocator);
+  Dart_CObject* cobject = cmessage->root;
   EXPECT_NOTNULL(cobject);
   EXPECT_EQ(Dart_CObject::kInt32, cobject->type);
   EXPECT_EQ(smi.Value(), cobject->value.as_int32);
-  free(cobject);
 }
 
 
 TEST_CASE(SerializeSmi2) {
   // Write snapshot with object content.
   uint8_t* buffer;
-  SnapshotWriter writer(Snapshot::kMessage, &buffer, &allocator);
+  SnapshotWriter writer(Snapshot::kMessage, &buffer, &malloc_allocator);
   const Smi& smi = Smi::Handle(Smi::New(-1));
   writer.WriteObject(smi.raw());
   writer.FinalizeBuffer();
 
   // Create a snapshot object using the buffer.
   const Snapshot* snapshot = Snapshot::SetupFromBuffer(buffer);
 
   // Read object back from the snapshot.
   SnapshotReader reader(snapshot, Isolate::Current());
   const Object& serialized_object = Object::Handle(reader.ReadObject());
   EXPECT(Equals(smi, serialized_object));
 
   // Read object back from the snapshot into a C structure.
-  CMessageReader mreader(buffer + Snapshot::kHeaderSize,
-                         writer.BytesWritten(),
-                         &allocator);
-  Dart_CObject* cobject = mreader.ReadObject();
+  Zone zone(Isolate::Current());
+  Dart_CMessage* cmessage = DecodeMessage(buffer + Snapshot::kHeaderSize,
+                                          writer.BytesWritten(),
+                                          &zone_allocator);
+  Dart_CObject* cobject = cmessage->root;
   EXPECT_NOTNULL(cobject);
   EXPECT_EQ(Dart_CObject::kInt32, cobject->type);
   EXPECT_EQ(smi.Value(), cobject->value.as_int32);
-  free(cobject);
 }
 
 
 TEST_CASE(SerializeDouble) {
   // Write snapshot with object content.
   uint8_t* buffer;
-  SnapshotWriter writer(Snapshot::kMessage, &buffer, &allocator);
+  SnapshotWriter writer(Snapshot::kMessage, &buffer, &malloc_allocator);
   const Double& dbl = Double::Handle(Double::New(101.29));
   writer.WriteObject(dbl.raw());
   writer.FinalizeBuffer();
 
   // Create a snapshot object using the buffer.
   const Snapshot* snapshot = Snapshot::SetupFromBuffer(buffer);
 
   // Read object back from the snapshot.
   SnapshotReader reader(snapshot, Isolate::Current());
   const Object& serialized_object = Object::Handle(reader.ReadObject());
   EXPECT(Equals(dbl, serialized_object));
 
   // Read object back from the snapshot into a C structure.
-  CMessageReader mreader(buffer + Snapshot::kHeaderSize,
-                         writer.BytesWritten(),
-                         &allocator);
-  Dart_CObject* cobject = mreader.ReadObject();
+  Zone zone(Isolate::Current());
+  Dart_CMessage* cmessage = DecodeMessage(buffer + Snapshot::kHeaderSize,
+                                          writer.BytesWritten(),
+                                          &zone_allocator);
+  Dart_CObject* cobject = cmessage->root;
   EXPECT_NOTNULL(cobject);
   EXPECT_EQ(Dart_CObject::kDouble, cobject->type);
   EXPECT_EQ(dbl.value(), cobject->value.as_double);
-  free(cobject);
 }
 
 
 TEST_CASE(SerializeBool) {
   // Write snapshot with object content.
   uint8_t* buffer;
-  SnapshotWriter writer(Snapshot::kMessage, &buffer, &allocator);
+  SnapshotWriter writer(Snapshot::kMessage, &buffer, &malloc_allocator);
   const Bool& bool1 = Bool::Handle(Bool::True());
   const Bool& bool2 = Bool::Handle(Bool::False());
   writer.WriteObject(bool1.raw());
   writer.WriteObject(bool2.raw());
   writer.FinalizeBuffer();
 
   // Create a snapshot object using the buffer.
   const Snapshot* snapshot = Snapshot::SetupFromBuffer(buffer);
 
   // Read object back from the snapshot.
   SnapshotReader reader(snapshot, Isolate::Current());
   EXPECT(Bool::True() == reader.ReadObject());
   EXPECT(Bool::False() == reader.ReadObject());
+}
+
+
+TEST_CASE(SerializeTrue) {
+  // Write snapshot with true object.
+  uint8_t* buffer;
+  SnapshotWriter writer(Snapshot::kMessage, &buffer, &malloc_allocator);
+  const Bool& bl = Bool::Handle(Bool::True());
+  writer.WriteObject(bl.raw());
+  writer.FinalizeBuffer();
+
+  // Create a snapshot object using the buffer.
+  Snapshot::SetupFromBuffer(buffer);
 
   // Read object back from the snapshot into a C structure.
-  CMessageReader mreader(buffer + Snapshot::kHeaderSize,
-                         writer.BytesWritten(),
-                         &allocator);
-  Dart_CObject* cobject1 = mreader.ReadObject();
-  EXPECT_NOTNULL(cobject1);
-  EXPECT_EQ(Dart_CObject::kBool, cobject1->type);
-  EXPECT_EQ(true, cobject1->value.as_bool);
-  Dart_CObject* cobject2 = mreader.ReadObject();
-  EXPECT_NOTNULL(cobject2);
-  EXPECT_EQ(Dart_CObject::kBool, cobject2->type);
-  EXPECT_EQ(false, cobject2->value.as_bool);
-  free(cobject1);
-  free(cobject2);
+  Zone zone(Isolate::Current());
+  Dart_CMessage* cmessage = DecodeMessage(buffer + Snapshot::kHeaderSize,
+                                          writer.BytesWritten(),
+                                          &zone_allocator);
+  Dart_CObject* cobject = cmessage->root;
+  EXPECT_NOTNULL(cobject);
+  EXPECT_EQ(Dart_CObject::kBool, cobject->type);
+  EXPECT_EQ(true, cobject->value.as_bool);
+}
+
+
+TEST_CASE(SerializeFalse) {
+  // Write snapshot with false object.
+  uint8_t* buffer;
+  SnapshotWriter writer(Snapshot::kMessage, &buffer, &malloc_allocator);
+  const Bool& bl = Bool::Handle(Bool::False());
+  writer.WriteObject(bl.raw());
+  writer.FinalizeBuffer();
+
+  // Create a snapshot object using the buffer.
+  Snapshot::SetupFromBuffer(buffer);
+
+  // Read object back from the snapshot into a C structure.
+  Zone zone(Isolate::Current());
+  Dart_CMessage* cmessage = DecodeMessage(buffer + Snapshot::kHeaderSize,
+                                          writer.BytesWritten(),
+                                          &zone_allocator);
+  Dart_CObject* cobject = cmessage->root;
+  EXPECT_NOTNULL(cobject);
+  EXPECT_EQ(Dart_CObject::kBool, cobject->type);
+  EXPECT_EQ(false, cobject->value.as_bool);
 }
 
 
 TEST_CASE(SerializeBigint) {
   // Write snapshot with object content.
   uint8_t* buffer;
-  SnapshotWriter writer(Snapshot::kMessage, &buffer, &allocator);
+  SnapshotWriter writer(Snapshot::kMessage, &buffer, &malloc_allocator);
   const Bigint& bigint = Bigint::Handle(Bigint::New(0xfffffffffLL));
   writer.WriteObject(bigint.raw());
   writer.FinalizeBuffer();
 
   // Create a snapshot object using the buffer.
   const Snapshot* snapshot = Snapshot::SetupFromBuffer(buffer);
 
   // Read object back from the snapshot.
   SnapshotReader reader(snapshot, Isolate::Current());
   Bigint& obj = Bigint::Handle();
   obj ^= reader.ReadObject();
   OS::Print("%lld", BigintOperations::ToInt64(obj));
   EXPECT_EQ(BigintOperations::ToInt64(bigint), BigintOperations::ToInt64(obj));
 
   // Read object back from the snapshot into a C structure.
-  CMessageReader mreader(buffer + Snapshot::kHeaderSize,
-                         writer.BytesWritten(),
-                         &allocator);
-  Dart_CObject* cobject = mreader.ReadObject();
+  Zone zone(Isolate::Current());
+  Dart_CMessage* cmessage = DecodeMessage(buffer + Snapshot::kHeaderSize,
+                                          writer.BytesWritten(),
+                                          &zone_allocator);
+  Dart_CObject* cobject = cmessage->root;
   // Bigint not supported.
   EXPECT(cobject == NULL);
 }
 
 
 TEST_CASE(SerializeSingletons) {
   // Write snapshot with object content.
   uint8_t* buffer;
-  SnapshotWriter writer(Snapshot::kMessage, &buffer, &allocator);
+  SnapshotWriter writer(Snapshot::kMessage, &buffer, &malloc_allocator);
   writer.WriteObject(Object::class_class());
   writer.WriteObject(Object::null_class());
   writer.WriteObject(Object::type_class());
   writer.WriteObject(Object::type_parameter_class());
   writer.WriteObject(Object::instantiated_type_class());
   writer.WriteObject(Object::abstract_type_arguments_class());
   writer.WriteObject(Object::type_arguments_class());
   writer.WriteObject(Object::instantiated_type_arguments_class());
   writer.WriteObject(Object::function_class());
   writer.WriteObject(Object::field_class());
@@ skipping 31 matching lines @@
   EXPECT(Object::pc_descriptors_class() == reader.ReadObject());
   EXPECT(Object::exception_handlers_class() == reader.ReadObject());
   EXPECT(Object::context_class() == reader.ReadObject());
   EXPECT(Object::context_scope_class() == reader.ReadObject());
 }
 
 
 TEST_CASE(SerializeString) {
   // Write snapshot with object content.
   uint8_t* buffer;
-  SnapshotWriter writer(Snapshot::kMessage, &buffer, &allocator);
+  SnapshotWriter writer(Snapshot::kMessage, &buffer, &malloc_allocator);
   static const char* cstr = "This string shall be serialized";
   String& str = String::Handle(String::New(cstr));
   writer.WriteObject(str.raw());
   writer.FinalizeBuffer();
 
   // Create a snapshot object using the buffer.
   const Snapshot* snapshot = Snapshot::SetupFromBuffer(buffer);
 
   // Read object back from the snapshot.
   SnapshotReader reader(snapshot, Isolate::Current());
   String& serialized_str = String::Handle();
   serialized_str ^= reader.ReadObject();
   EXPECT(str.Equals(serialized_str));
 
   // Read object back from the snapshot into a C structure.
-  CMessageReader mreader(buffer + Snapshot::kHeaderSize,
-                         writer.BytesWritten(),
-                         &allocator);
-  Dart_CObject* cobject = mreader.ReadObject();
+  Zone zone(Isolate::Current());
+  Dart_CMessage* cmessage = DecodeMessage(buffer + Snapshot::kHeaderSize,
+                                          writer.BytesWritten(),
+                                          &zone_allocator);
+  Dart_CObject* cobject = cmessage->root;
   EXPECT_EQ(Dart_CObject::kString, cobject->type);
   EXPECT_STREQ(cstr, cobject->value.as_string);
-  free(cobject);
 }
 
 
 TEST_CASE(SerializeArray) {
   // Write snapshot with object content.
   uint8_t* buffer;
-  SnapshotWriter writer(Snapshot::kMessage, &buffer, &allocator);
+  SnapshotWriter writer(Snapshot::kMessage, &buffer, &malloc_allocator);
   const int kArrayLength = 10;
   Array& array = Array::Handle(Array::New(kArrayLength));
   Smi& smi = Smi::Handle();
   for (int i = 0; i < kArrayLength; i++) {
     smi ^= Smi::New(i);
     array.SetAt(i, smi);
   }
   writer.WriteObject(array.raw());
   writer.FinalizeBuffer();
 
   // Create a snapshot object using the buffer.
   const Snapshot* snapshot = Snapshot::SetupFromBuffer(buffer);
 
   // Read object back from the snapshot.
   SnapshotReader reader(snapshot, Isolate::Current());
   Array& serialized_array = Array::Handle();
   serialized_array ^= reader.ReadObject();
   EXPECT(array.Equals(serialized_array));
 
   // Read object back from the snapshot into a C structure.
-  CMessageReader mreader(buffer + Snapshot::kHeaderSize,
-                         writer.BytesWritten(),
-                         &allocator);
-  Dart_CObject* cobject = mreader.ReadObject();
+  Zone zone(Isolate::Current());
+  Dart_CMessage* cmessage = DecodeMessage(buffer + Snapshot::kHeaderSize,
+                                          writer.BytesWritten(),
+                                          &zone_allocator);
+  Dart_CObject* cobject = cmessage->root;
   EXPECT_EQ(Dart_CObject::kArray, cobject->type);
   EXPECT_EQ(kArrayLength, cobject->value.as_array.length);
   for (int i = 0; i < kArrayLength; i++) {
     Dart_CObject* element = cobject->value.as_array.values[i];
     EXPECT_EQ(Dart_CObject::kInt32, element->type);
     EXPECT_EQ(i, element->value.as_int32);
-    free(element);
   }
-  free(cobject);
 }
 
 
 TEST_CASE(SerializeEmptyArray) {
   // Write snapshot with object content.
   uint8_t* buffer;
-  SnapshotWriter writer(Snapshot::kMessage, &buffer, &allocator);
+  SnapshotWriter writer(Snapshot::kMessage, &buffer, &malloc_allocator);
   const int kArrayLength = 0;
   Array& array = Array::Handle(Array::New(kArrayLength));
   writer.WriteObject(array.raw());
   writer.FinalizeBuffer();
 
   // Create a snapshot object using the buffer.
   const Snapshot* snapshot = Snapshot::SetupFromBuffer(buffer);
 
   // Read object back from the snapshot.
   SnapshotReader reader(snapshot, Isolate::Current());
   Array& serialized_array = Array::Handle();
   serialized_array ^= reader.ReadObject();
   EXPECT(array.Equals(serialized_array));
 
   // Read object back from the snapshot into a C structure.
-  CMessageReader mreader(buffer + Snapshot::kHeaderSize,
-                         writer.BytesWritten(),
-                         &allocator);
-  Dart_CObject* cobject = mreader.ReadObject();
+  Zone zone(Isolate::Current());
+  Dart_CMessage* cmessage = DecodeMessage(buffer + Snapshot::kHeaderSize,
+                                          writer.BytesWritten(),
+                                          &zone_allocator);
+  Dart_CObject* cobject = cmessage->root;
   EXPECT_EQ(Dart_CObject::kArray, cobject->type);
   EXPECT_EQ(kArrayLength, cobject->value.as_array.length);
   EXPECT(cobject->value.as_array.values == NULL);
-  free(cobject);
 }
 
 
 TEST_CASE(SerializeScript) {
   const char* kScriptChars =
       "class A {\n"
       "  static bar() { return 42; }\n"
       "  static fly() { return 5; }\n"
       "}\n";
 
   String& url = String::Handle(String::New("dart-test:SerializeScript"));
   String& source = String::Handle(String::New(kScriptChars));
   Script& script = Script::Handle(Script::New(url, source, RawScript::kSource));
   const String& lib_url = String::Handle(String::NewSymbol("TestLib"));
   Library& lib = Library::Handle(Library::New(lib_url));
   lib.Register();
   EXPECT(CompilerTest::TestCompileScript(lib, script));
 
   // Write snapshot with object content.
   uint8_t* buffer;
-  SnapshotWriter writer(Snapshot::kScript, &buffer, &allocator);
+  SnapshotWriter writer(Snapshot::kScript, &buffer, &malloc_allocator);
   writer.WriteObject(script.raw());
   writer.FinalizeBuffer();
 
   // Create a snapshot object using the buffer.
   const Snapshot* snapshot = Snapshot::SetupFromBuffer(buffer);
 
   // Read object back from the snapshot.
   SnapshotReader reader(snapshot, Isolate::Current());
   Script& serialized_script = Script::Handle();
   serialized_script ^= reader.ReadObject();
@@ skipping 48 matching lines @@
 
     // Create a test library and Load up a test script in it.
     TestCase::LoadTestScript(kScriptChars, NULL);
     timer1.Stop();
     OS::PrintErr("Without Snapshot: %dus\n", timer1.TotalElapsedTime());
 
     // Write snapshot with object content.
     Isolate* isolate = Isolate::Current();
     Zone zone(isolate);
     HandleScope scope(isolate);
-    SnapshotWriter writer(Snapshot::kFull, &buffer, &allocator);
+    SnapshotWriter writer(Snapshot::kFull, &buffer, &malloc_allocator);
     writer.WriteFullSnapshot();
   }
 
   // Now Create another isolate using the snapshot and execute a method
   // from the script.
   Timer timer2(true, "Snapshot_test");
   timer2.Start();
   TestCase::CreateTestIsolateFromSnapshot(buffer);
   {
     Dart_EnterScope();  // Start a Dart API scope for invoking API functions.
@@ skipping 35 matching lines @@
     Zone zone(isolate);
     HandleScope scope(isolate);
 
     // Create a test library and Load up a test script in it.
     Dart_Handle lib = TestCase::LoadTestScript(kScriptChars, NULL);
     ClassFinalizer::FinalizePendingClasses();
     timer1.Stop();
     OS::PrintErr("Without Snapshot: %dus\n", timer1.TotalElapsedTime());
 
     // Write snapshot with object content.
-    SnapshotWriter writer(Snapshot::kFull, &buffer, &allocator);
+    SnapshotWriter writer(Snapshot::kFull, &buffer, &malloc_allocator);
     writer.WriteFullSnapshot();
 
     // Invoke a function which returns an object.
     Dart_Handle result = Dart_InvokeStatic(lib,
                                Dart_NewString("FieldsTest"),
                                Dart_NewString("testMain"),
                                0,
                                NULL);
     EXPECT_VALID(result);
   }
@@ skipping 116 matching lines @@
     Dart_ExitScope();
   }
   Dart_ShutdownIsolate();
   free(full_snapshot);
   free(script_snapshot);
 }
 
 
 TEST_CASE(IntArrayMessage) {
   uint8_t* buffer = NULL;
-  MessageWriter writer(&buffer, &allocator);
+  MessageWriter writer(&buffer, &malloc_allocator);
 
   static const int kArrayLength = 2;
   intptr_t data[kArrayLength] = {1, 2};
   int len = kArrayLength;
   writer.WriteMessage(len, data);
 
   // Read object back from the snapshot into a C structure.
-  CMessageReader mreader(buffer + Snapshot::kHeaderSize,
-                         writer.BytesWritten(),
-                         &allocator);
-  Dart_CObject* value = mreader.ReadObject();
-  EXPECT_EQ(Dart_CObject::kArray, value->type);
-  EXPECT_EQ(kArrayLength, value->value.as_array.length);
+  Zone zone(Isolate::Current());
+  Dart_CMessage* cmessage = DecodeMessage(buffer + Snapshot::kHeaderSize,
+                                          writer.BytesWritten(),
+                                          &zone_allocator);
+  Dart_CObject* cobject = cmessage->root;
+  EXPECT_EQ(Dart_CObject::kArray, cobject->type);
+  EXPECT_EQ(kArrayLength, cobject->value.as_array.length);
   for (int i = 0; i < kArrayLength; i++) {
-    Dart_CObject* element = value->value.as_array.values[i];
+    Dart_CObject* element = cobject->value.as_array.values[i];
     EXPECT_EQ(Dart_CObject::kInt32, element->type);
     EXPECT_EQ(i + 1, element->value.as_int32);
-    free(element);
   }
-  free(value);
 }
 
 
 // Helper function to call a top level Dart function, serialize the
 // result and deserialize the result into a Dart_CObject structure.
-static Dart_CObject* GetDeserializedDartObject(Dart_Handle lib,
-                                               const char* dart_function) {
+static Dart_CMessage* GetDeserializedDartMessage(Dart_Handle lib,
+                                                 const char* dart_function) {
   Dart_Handle result;
   result = Dart_InvokeStatic(lib,
                              Dart_NewString(""),
                              Dart_NewString(dart_function),
                              0,
                              NULL);
   EXPECT_VALID(result);
 
   // Serialize the list into a message.
   uint8_t* buffer;
-  SnapshotWriter writer(Snapshot::kMessage, &buffer, &allocator);
+  SnapshotWriter writer(Snapshot::kMessage, &buffer, &malloc_allocator);
   const Object& list = Object::Handle(Api::UnwrapHandle(result));
   writer.WriteObject(list.raw());
   writer.FinalizeBuffer();
 
   // Read object back from the snapshot into a C structure.
-  CMessageReader reader(buffer + Snapshot::kHeaderSize,
-                        writer.BytesWritten(),
-                        &allocator);
-  Dart_CObject* value = reader.ReadObject();
-  free(buffer);
-  return value;
+  Dart_CMessage* cmessage = DecodeMessage(buffer + Snapshot::kHeaderSize,
+                                          writer.BytesWritten(),
+                                          &zone_allocator);
+  return cmessage;
 }
 
 
 UNIT_TEST_CASE(DartGeneratedMessages) {
   static const char* kCustomIsolateScriptChars =
       "getSmi() {\n"
       "  return 42;\n"
       "}\n"
       "getString() {\n"
       "  return \"Hello, world!\";\n"
@@ skipping 24 matching lines @@
                                     0,
                                     NULL);
   EXPECT_VALID(string_result);
   EXPECT(Dart_IsString(string_result));
 
   {
     DARTSCOPE_NOCHECKS(isolate);
 
     {
       uint8_t* buffer;
-      SnapshotWriter writer(Snapshot::kMessage, &buffer, &allocator);
+      SnapshotWriter writer(Snapshot::kMessage, &buffer, &malloc_allocator);
       Smi& smi = Smi::Handle();
       smi ^= Api::UnwrapHandle(smi_result);
       writer.WriteObject(smi.raw());
       writer.FinalizeBuffer();
 
       // Read object back from the snapshot into a C structure.
-      CMessageReader mreader(buffer + Snapshot::kHeaderSize,
-                             writer.BytesWritten(),
-                             &allocator);
-      Dart_CObject* value = mreader.ReadObject();
-      EXPECT_NOTNULL(value);
-      EXPECT_EQ(Dart_CObject::kInt32, value->type);
-      EXPECT_EQ(42, value->value.as_int32);
-      free(value);
-      free(buffer);
+      Zone zone(Isolate::Current());
+      Dart_CMessage* cmessage = DecodeMessage(buffer + Snapshot::kHeaderSize,
+                                              writer.BytesWritten(),
+                                              &zone_allocator);
+      Dart_CObject* cobject = cmessage->root;
+      EXPECT_NOTNULL(cobject);
+      EXPECT_EQ(Dart_CObject::kInt32, cobject->type);
+      EXPECT_EQ(42, cobject->value.as_int32);
     }
     {
       uint8_t* buffer;
-      SnapshotWriter writer(Snapshot::kMessage, &buffer, &allocator);
+      SnapshotWriter writer(Snapshot::kMessage, &buffer, &malloc_allocator);
       String& str = String::Handle();
       str ^= Api::UnwrapHandle(string_result);
       writer.WriteObject(str.raw());
       writer.FinalizeBuffer();
 
       // Read object back from the snapshot into a C structure.
-      CMessageReader mreader(buffer + Snapshot::kHeaderSize,
-                             writer.BytesWritten(),
-                             &allocator);
-      Dart_CObject* value = mreader.ReadObject();
-      EXPECT_NOTNULL(value);
-      EXPECT_EQ(Dart_CObject::kString, value->type);
-      EXPECT_STREQ("Hello, world!", value->value.as_string);
-      free(value);
-      free(buffer);
+      Zone zone(Isolate::Current());
+      Dart_CMessage* cmessage = DecodeMessage(buffer + Snapshot::kHeaderSize,
+                                              writer.BytesWritten(),
+                                              &zone_allocator);
+      Dart_CObject* cobject = cmessage->root;
+      EXPECT_NOTNULL(cobject);
+      EXPECT_EQ(Dart_CObject::kString, cobject->type);
+      EXPECT_STREQ("Hello, world!", cobject->value.as_string);
     }
   }
   Dart_ExitScope();
   Dart_ShutdownIsolate();
 }
 
 
 UNIT_TEST_CASE(DartGeneratedListMessages) {
   const int kArrayLength = 10;
   static const char* kScriptChars =
@@ skipping 26 matching lines @@
   Dart_EnterScope();
 
   Dart_Handle lib = TestCase::LoadTestScript(kScriptChars, NULL);
   EXPECT_VALID(lib);
 
   {
     DARTSCOPE_NOCHECKS(isolate);
 
     {
       // Generate a list of nulls from Dart code.
-      Dart_CObject* value = GetDeserializedDartObject(lib, "getList");
+      Zone zone(Isolate::Current());
+      Dart_CMessage* cmessage = GetDeserializedDartMessage(lib, "getList");
+      Dart_CObject* value = cmessage->root;
       EXPECT_NOTNULL(value);
       EXPECT_EQ(Dart_CObject::kArray, value->type);
       EXPECT_EQ(kArrayLength, value->value.as_array.length);
       for (int i = 0; i < kArrayLength; i++) {
         EXPECT_EQ(Dart_CObject::kNull, value->value.as_array.values[i]->type);
-        free(value->value.as_array.values[i]);
       }
-      free(value);
     }
     {
       // Generate a list of ints from Dart code.
-      Dart_CObject* value = GetDeserializedDartObject(lib, "getIntList");
+      Zone zone(Isolate::Current());
+      Dart_CMessage* cmessage = GetDeserializedDartMessage(lib, "getIntList");
+      Dart_CObject* value = cmessage->root;
       EXPECT_NOTNULL(value);
       EXPECT_EQ(Dart_CObject::kArray, value->type);
       EXPECT_EQ(kArrayLength, value->value.as_array.length);
       for (int i = 0; i < kArrayLength; i++) {
         EXPECT_EQ(Dart_CObject::kInt32, value->value.as_array.values[i]->type);
         EXPECT_EQ(i, value->value.as_array.values[i]->value.as_int32);
-        free(value->value.as_array.values[i]);
       }
-      free(value);
     }
     {
       // Generate a list of strings from Dart code.
-      Dart_CObject* value = GetDeserializedDartObject(lib, "getStringList");
+      Zone zone(Isolate::Current());
+      Dart_CMessage* cmessage =
+          GetDeserializedDartMessage(lib, "getStringList");
+      Dart_CObject* value = cmessage->root;
       EXPECT_NOTNULL(value);
       EXPECT_EQ(Dart_CObject::kArray, value->type);
       EXPECT_EQ(kArrayLength, value->value.as_array.length);
       for (int i = 0; i < kArrayLength; i++) {
         EXPECT_EQ(Dart_CObject::kString, value->value.as_array.values[i]->type);
         char buffer[3];
         snprintf(buffer, sizeof(buffer), "%d", i);
         EXPECT_STREQ(buffer, value->value.as_array.values[i]->value.as_string);
-        free(value->value.as_array.values[i]);
       }
-      free(value);
     }
     {
       // Generate a list of objects of different types from Dart code.
-      Dart_CObject* value = GetDeserializedDartObject(lib, "getMixedList");
+      Zone zone(Isolate::Current());
+      Dart_CMessage* cmessage = GetDeserializedDartMessage(lib, "getMixedList");
+      Dart_CObject* value = cmessage->root;
       EXPECT_NOTNULL(value);
       EXPECT_EQ(Dart_CObject::kArray, value->type);
       EXPECT_EQ(kArrayLength, value->value.as_array.length);
 
       EXPECT_EQ(Dart_CObject::kInt32, value->value.as_array.values[0]->type);
       EXPECT_EQ(0, value->value.as_array.values[0]->value.as_int32);
       EXPECT_EQ(Dart_CObject::kString, value->value.as_array.values[1]->type);
       EXPECT_STREQ("1", value->value.as_array.values[1]->value.as_string);
       EXPECT_EQ(Dart_CObject::kDouble, value->value.as_array.values[2]->type);
       EXPECT_EQ(2.2, value->value.as_array.values[2]->value.as_double);
       EXPECT_EQ(Dart_CObject::kBool, value->value.as_array.values[3]->type);
       EXPECT_EQ(true, value->value.as_array.values[3]->value.as_bool);
 
       for (int i = 0; i < kArrayLength; i++) {
         if (i > 3) {
           EXPECT_EQ(Dart_CObject::kNull, value->value.as_array.values[i]->type);
         }
-        free(value->value.as_array.values[i]);
       }
-      free(value);
     }
   }
   Dart_ExitScope();
   Dart_ShutdownIsolate();
 }
 
 
 UNIT_TEST_CASE(DartGeneratedListMessagesWithBackref) {
   const int kArrayLength = 10;
   static const char* kScriptChars =
@@ skipping 31 matching lines @@
   Dart_EnterScope();
 
   Dart_Handle lib = TestCase::LoadTestScript(kScriptChars, NULL);
   EXPECT_VALID(lib);
 
   {
     DARTSCOPE_NOCHECKS(isolate);
 
     {
       // Generate a list of strings from Dart code.
-      Dart_CObject* object = GetDeserializedDartObject(lib, "getStringList");
+      Zone zone(Isolate::Current());
+      Dart_CMessage* cmessage =
+          GetDeserializedDartMessage(lib, "getStringList");
+      Dart_CObject* object = cmessage->root;
       EXPECT_NOTNULL(object);
       EXPECT_EQ(Dart_CObject::kArray, object->type);
       EXPECT_EQ(kArrayLength, object->value.as_array.length);
       for (int i = 0; i < kArrayLength; i++) {
         Dart_CObject* element = object->value.as_array.values[i];
         EXPECT_EQ(object->value.as_array.values[0], element);
         EXPECT_EQ(Dart_CObject::kString, element->type);
         EXPECT_STREQ("Hello, world!", element->value.as_string);
       }
-      free(object->value.as_array.values[0]);
-      free(object);
     }
     {
       // Generate a list of doubles from Dart code.
-      Dart_CObject* object = GetDeserializedDartObject(lib, "getDoubleList");
+      Zone zone(Isolate::Current());
+      Dart_CMessage* cmessage =
+          GetDeserializedDartMessage(lib, "getDoubleList");
+      Dart_CObject* object = cmessage->root;
       EXPECT_NOTNULL(object);
       EXPECT_EQ(Dart_CObject::kArray, object->type);
       EXPECT_EQ(kArrayLength, object->value.as_array.length);
       for (int i = 0; i < kArrayLength; i++) {
         Dart_CObject* element = object->value.as_array.values[i];
         EXPECT_EQ(object->value.as_array.values[0], element);
         EXPECT_EQ(Dart_CObject::kDouble, element->type);
         EXPECT_EQ(3.14, element->value.as_double);
       }
-      free(object->value.as_array.values[0]);
-      free(object);
     }
     {
       // Generate a list of objects of different types from Dart code.
-      Dart_CObject* object = GetDeserializedDartObject(lib, "getMixedList");
+      Zone zone(Isolate::Current());
+      Dart_CMessage* cmessage = GetDeserializedDartMessage(lib, "getMixedList");
+      Dart_CObject* object = cmessage->root;
       EXPECT_NOTNULL(object);
       EXPECT_EQ(Dart_CObject::kArray, object->type);
       EXPECT_EQ(kArrayLength, object->value.as_array.length);
       for (int i = 0; i < kArrayLength; i++) {
         Dart_CObject* element = object->value.as_array.values[i];
         if ((i % 2) == 0) {
           EXPECT_EQ(object->value.as_array.values[0], element);
           EXPECT_EQ(Dart_CObject::kString, element->type);
           EXPECT_STREQ("A", element->value.as_string);
         } else {
           EXPECT_EQ(object->value.as_array.values[1], element);
           EXPECT_EQ(Dart_CObject::kDouble, element->type);
           EXPECT_STREQ(2.72, element->value.as_double);
         }
       }
-      free(object->value.as_array.values[0]);
-      free(object->value.as_array.values[1]);
-      free(object);
     }
     {
       // Generate a list of objects of different types from Dart code.
-      Dart_CObject* object = GetDeserializedDartObject(lib, "getSelfRefList");
+      Zone zone(Isolate::Current());
+      Dart_CMessage* cmessage =
+          GetDeserializedDartMessage(lib, "getSelfRefList");
+      Dart_CObject* object = cmessage->root;
       EXPECT_NOTNULL(object);
       EXPECT_EQ(Dart_CObject::kArray, object->type);
       EXPECT_EQ(kArrayLength, object->value.as_array.length);
       for (int i = 0; i < kArrayLength; i++) {
         Dart_CObject* element = object->value.as_array.values[i];
         EXPECT_EQ(Dart_CObject::kArray, element->type);
         EXPECT_EQ(object, element);
       }
-      free(object);
     }
   }
   Dart_ExitScope();
   Dart_ShutdownIsolate();
 }
 
 #endif  // defined(TARGET_ARCH_IA32) || defined(TARGET_ARCH_X64).
 
 }  // namespace dart