Decode the Dart message into a Dart_CMessage structure before calling the native port callback

runtime/vm/snapshot.cc

Index: runtime/vm/snapshot.cc
diff --git a/runtime/vm/snapshot.cc b/runtime/vm/snapshot.cc
index 78fe6a70d2f910f8ec6c74c601e35cd268f996ad..3006984692476b84d6c5c2159ccf39f3d19591ba 100644
--- a/runtime/vm/snapshot.cc
+++ b/runtime/vm/snapshot.cc
@@ -441,8 +441,31 @@ CMessageReader::CMessageReader(const uint8_t* buffer,
                                intptr_t length,
                                ReAlloc alloc)
     : BaseReader(buffer, length),
+      zone_(NULL),
       alloc_(alloc),
       backward_references_(kNumInitialReferences) {
+  // When no explicit zone is used ensure that there is a current
+  // isolate zone as backward_references_ needs an isolate zone for
+  // allocation.
+  ASSERT(Isolate::Current() != NULL);
+  ASSERT(Isolate::Current()->current_zone() != NULL);
+  Init();
+}
+
+
+CMessageReader::CMessageReader(const uint8_t* buffer,
+                               intptr_t length,
+                               Zone* zone)
+    : BaseReader(buffer, length),
+      zone_(zone),
+      alloc_(NULL),
+      backward_references_(kNumInitialReferences, zone) {
+  ASSERT(zone != NULL);
+  Init();
+}
+
+
+void CMessageReader::Init() {
   // Initialize marker objects used to handle Lists.
   // TODO(sjesse): Remove this when message serialization format is
   // updated.
@@ -460,7 +483,8 @@ Dart_CMessage* CMessageReader::ReadMessage() {
   Dart_CObject* object = ReadObject();
 
   Dart_CMessage* message =
-      reinterpret_cast<Dart_CMessage*>(alloc_(NULL, 0, sizeof(Dart_CMessage)));
+      reinterpret_cast<Dart_CMessage*>(
+          Allocate(NULL, 0, sizeof(Dart_CMessage)));
   if (message == NULL) return NULL;
   message->root = object;
   return message;
@@ -473,11 +497,21 @@ intptr_t CMessageReader::LookupInternalClass(intptr_t class_header) {
   return header_value;
 }
 
+uint8_t* CMessageReader::Allocate(uint8_t* ptr,
+                                  intptr_t old_size,
+                                  intptr_t new_size) {
+  if (alloc_ != NULL) {
+    return alloc_(ptr, old_size, new_size);
+  } else {
+    return reinterpret_cast<uint8_t*>(
+        zone_->Reallocate(reinterpret_cast<uword>(ptr), old_size, new_size));
+  }
+}
 
 Dart_CObject* CMessageReader::AllocateDartCObject(Dart_CObject::Type type) {
   Dart_CObject* value =
       reinterpret_cast<Dart_CObject*>(
-          alloc_(NULL, 0, sizeof(Dart_CObject)));
+          Allocate(NULL, 0, sizeof(Dart_CObject)));
   value->type = type;
   return value;
 }
@@ -515,7 +549,7 @@ Dart_CObject* CMessageReader::AllocateDartCObjectString(intptr_t length) {
   // up to this area.
   Dart_CObject* value =
       reinterpret_cast<Dart_CObject*>(
-          alloc_(NULL, 0, sizeof(Dart_CObject) + length + 1));
+          Allocate(NULL, 0, sizeof(Dart_CObject) + length + 1));
   value->value.as_string = reinterpret_cast<char*>(value) + sizeof(*value);
   value->type = Dart_CObject::kString;
   return value;
@@ -528,7 +562,7 @@ Dart_CObject* CMessageReader::AllocateDartCObjectArray(intptr_t length) {
   // content is set up to this area.
   Dart_CObject* value =
       reinterpret_cast<Dart_CObject*>(
-          alloc_(NULL, 0, sizeof(Dart_CObject) + length * sizeof(value)));
+          Allocate(NULL, 0, sizeof(Dart_CObject) + length * sizeof(value)));
   value->type = Dart_CObject::kArray;
   value->value.as_array.length = length;
   if (length > 0) {