arangodb · cpjulia · Aug 12, 2025 · Aug 13, 2025 · Aug 13, 2025 · Aug 18, 2025
diff --git a/lib/Basics/SupervisedBuffer.h b/lib/Basics/SupervisedBuffer.h
@@ -0,0 +1,46 @@
+#pragma once
+
+#include "velocypack/Buffer.h"
+#include "Basics/ResourceUsage.h"
+
+namespace arangodb::velocypack {
+
+class SupervisedBuffer : public arangodb::velocypack::Buffer<uint8_t> {
+ public:
+  SupervisedBuffer() = default;
+
+  explicit SupervisedBuffer(ResourceMonitor& monitor)
+      : _usageScope(std::make_unique<ResourceUsageScope>(monitor)) {}
+
+  uint8_t* steal() override noexcept {
+    uint8_t* ptr = velocypack::Buffer<uint8_t>::steal();
+    if (_usageScope) {  // assume it exists without checking?
+      _usageScope->steal();
+    }
+    return ptr;
+  }
+
+ private:
+  void grow(ValueLength length) override {
+    auto currentCapacity = this->capacity();
+    velocypack::Buffer<uint8_t>::grow(length);
+    auto newCapacity = this->capacity();
+    if (_usageScope && newCapacity > currentCapacity) {
+      _usageScope->increase(newCapacity - currentCapacity);
+    }
+  }
+
+  void clear() override noexcept {
+    auto before = this->capacity();
+    Buffer<uint8_t>::clear();
+    auto after = this->capacity();
+    // if before > after, means that it has released usage from the heap
+    if (_usageScope && before > after) {
+      _usageScope->decrease(before - after);
+    }
+  }
+
+  std::unique_ptr<ResourceUsageScope> _usageScope;
+};
+
+}  // namespace arangodb::velocypack
diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
@@ -79,6 +79,7 @@ add_library(arango_basic_utils STATIC
         Basics/NumberUtils.cpp
         Basics/ReadWriteSpinLock.cpp
         Basics/ResourceUsage.cpp
+		Basics/SupervisedBuffer.h
         Basics/StringBufferAdvanced.cpp
         Basics/Utf8Helper.cpp
         Basics/VelocyPackHelper.cpp