#pragma once

#include "envoy/extensions/resource_monitors/fixed_heap/v3/fixed_heap.pb.h"

#include "envoy/server/resource_monitor.h"

namespace Envoy {

namespace Extensions {

namespace ResourceMonitors {

namespace FixedHeapMonitor {

/**

 * Helper class for getting memory heap stats.

 */

class MemoryStatsReader {

public:

  // Memory reserved for the process by the heap.

  virtual uint64_t reservedHeapBytes();

  // Memory in free, unmapped pages in the page heap.

  virtual uint64_t unmappedHeapBytes();

  // Memory in free, mapped pages in the page heap.

  virtual uint64_t freeMappedHeapBytes();

  // Memory currently allocated by the process.

  virtual uint64_t allocatedHeapBytes();

};

/**

 * Heap memory monitor with a statically configured maximum.

 */

class FixedHeapMonitor : public Server::ResourceMonitor {

public:

  FixedHeapMonitor(

      const envoy::extensions::resource_monitors::fixed_heap::v3::FixedHeapConfig& config,

      std::unique_ptr<MemoryStatsReader> stats = std::make_unique<MemoryStatsReader>());

  void updateResourceUsage(Server::ResourceUpdateCallbacks& callbacks) override;

private:

  const uint64_t max_heap_;

  std::unique_ptr<MemoryStatsReader> stats_;

};

} // namespace FixedHeapMonitor

} // namespace ResourceMonitors

} // namespace Extensions

} // namespace Envoy