android/libwvdrmengine/oemcrypto/util/include/scoped_object.h

// Copyright 2021 Google LLC. All Rights Reserved. This file and proprietary
// source code may only be used and distributed under the Widevine License
// Agreement.
//
//  Reference implementation utilities of OEMCrypto APIs
//
#ifndef WVOEC_UTIL_SCOPED_OBJECT_H_
#define WVOEC_UTIL_SCOPED_OBJECT_H_

namespace wvoec {
namespace util {
// A generic wrapper around pointer.  This allows for automatic
// memory clean up when the ScopedObject variable goes out of scope.
// This is intended to be used with OpenSSL/BoringSSL structs.
template <typename Type, void Destructor(Type*)>
class ScopedObject {
 public:
  ScopedObject() : ptr_(nullptr) {}
  ScopedObject(Type* ptr) : ptr_(ptr) {}
  ~ScopedObject() {
    if (ptr_) {
      Destructor(ptr_);
      ptr_ = nullptr;
    }
  }

  // Copy construction and assignment are not allowed.
  ScopedObject(const ScopedObject& other) = delete;
  ScopedObject& operator=(const ScopedObject& other) = delete;

  // Move construction and assignment are allowed.
  ScopedObject(ScopedObject&& other) : ptr_(other.ptr_) {
    other.ptr_ = nullptr;
  }
  ScopedObject& operator=(ScopedObject&& other) {
    if (ptr_) {
      Destructor(ptr_);
    }
    ptr_ = other.ptr_;
    other.ptr_ = nullptr;
    return *this;
  }

  explicit operator bool() const { return ptr_ != nullptr; }

  Type& operator*() { return *ptr_; }
  Type* get() const { return ptr_; }
  Type* operator->() const { return ptr_; }

  // Releasing the pointer will remove the responsibility of the
  // ScopedObject to clean up the pointer.
  Type* release() {
    Type* temp = ptr_;
    ptr_ = nullptr;
    return temp;
  }

  void reset(Type* ptr = nullptr) {
    if (ptr_) {
      Destructor(ptr_);
    }
    ptr_ = ptr;
  }

 private:
  Type* ptr_ = nullptr;
};
}  // namespace util
}  // namespace wvoec
#endif  // WVOEC_UTIL_SCOPED_OBJECT_H_