components/variations/scoped_variations_ids_provider.h

// Copyright 2021 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef COMPONENTS_VARIATIONS_SCOPED_VARIATIONS_IDS_PROVIDER_H_
#define COMPONENTS_VARIATIONS_SCOPED_VARIATIONS_IDS_PROVIDER_H_

#include "base/memory/raw_ptr.h"
#include "components/variations/variations_ids_provider.h"

namespace variations::test {


// A helper class for tests that need to create a `VariationsIdsProvider`
// instance for the duration of the test.
class ScopedVariationsIdsProvider {
 public:
  explicit ScopedVariationsIdsProvider(VariationsIdsProvider::Mode mode);
  ~ScopedVariationsIdsProvider();

  ScopedVariationsIdsProvider(const ScopedVariationsIdsProvider&) = delete;
  ScopedVariationsIdsProvider& operator=(const ScopedVariationsIdsProvider&) =
      delete;

  VariationsIdsProvider* operator->();
  VariationsIdsProvider& operator*();

 private:
  // A pointer to the previous instance of `VariationsIdsProvider` that is
  // in place when this class is instantiated. This is used to restore the
  // global instance pointer to the previous instance upon destruction.
  raw_ptr<VariationsIdsProvider> previous_instance_ = nullptr;

  // The scoped instance of `VariationsIdsProvider` that is created and
  // destroyed by this class. This should match the global variations ids
  // provider pointer for the lifetime of this `ScopedVariationsIdsProvider
  // instance, as verified by CHECKs in the implementation.
  raw_ptr<VariationsIdsProvider> current_instance_ = nullptr;
};

}  // namespace variations::test

#endif  // COMPONENTS_VARIATIONS_SCOPED_VARIATIONS_IDS_PROVIDER_H_