Reimplemented zone memory tracking to avoid race conditions that were causing crashes in the previo…

runtime/vm/dart_api_state.h

 // 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.
 
 #ifndef RUNTIME_VM_DART_API_STATE_H_
 #define RUNTIME_VM_DART_API_STATE_H_
 
 #include "include/dart_api.h"
 
 #include "platform/utils.h"
@@ skipping 658 matching lines @@
 
 class ApiNativeScope {
  public:
   ApiNativeScope() {
     // Currently no support for nesting native scopes.
     ASSERT(Current() == NULL);
     OSThread::SetThreadLocal(Api::api_native_key_,
                              reinterpret_cast<uword>(this));
     // We manually increment the memory usage counter since there is memory
     // initially allocated within the zone on creation.
-    IncrementNativeScopeMemoryUsage(zone_.GetZone()->CapacityInBytes());
+    IncrementNativeScopeMemoryCapacity(zone_.GetZone()->CapacityInBytes());
   }
 
   ~ApiNativeScope() {
     ASSERT(Current() == this);
     OSThread::SetThreadLocal(Api::api_native_key_, 0);
     // We must also manually decrement the memory usage counter since the native
     // is still holding it's initial memory and ~Zone() won't be able to
     // determine which memory usage counter to decrement.
-    DecrementNativeScopeMemoryUsage(zone_.GetZone()->CapacityInBytes());
+    DecrementNativeScopeMemoryCapacity(zone_.GetZone()->CapacityInBytes());
   }
 
   static inline ApiNativeScope* Current() {
     return reinterpret_cast<ApiNativeScope*>(
         OSThread::GetThreadLocal(Api::api_native_key_));
   }
 
-  static intptr_t current_memory_usage() { return current_memory_usage_; }
+  static uintptr_t current_memory_usage() { return current_memory_usage_; }
 
-  static void IncrementNativeScopeMemoryUsage(intptr_t size) {
+  static void IncrementNativeScopeMemoryCapacity(intptr_t size) {
     AtomicOperations::IncrementBy(&current_memory_usage_, size);
   }
 
-  static void DecrementNativeScopeMemoryUsage(intptr_t size) {
+  static void DecrementNativeScopeMemoryCapacity(intptr_t size) {
     AtomicOperations::DecrementBy(&current_memory_usage_, size);
   }
 
   Zone* zone() {
     Zone* result = zone_.GetZone();
     ASSERT(result->handles()->CountScopedHandles() == 0);
     ASSERT(result->handles()->CountZoneHandles() == 0);
     return result;
   }
 
@@ skipping 150 matching lines @@
   ref->set_callback(callback);
   ref->set_is_queued_for_finalization(false);
   // This may trigger GC, so it must be called last.
   ref->SetExternalSize(external_size, isolate);
   return ref;
 }
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_DART_API_STATE_H_