chromium/components/prefs/wrap_with_prefix_pref_store.h

// Copyright 2024 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_PREFS_WRAP_WITH_PREFIX_PREF_STORE_H_
#define COMPONENTS_PREFS_WRAP_WITH_PREFIX_PREF_STORE_H_

#include <optional>
#include <string>
#include <string_view>

#include "base/observer_list.h"
#include "components/prefs/persistent_pref_store.h"

// This is a wrapper over another PersistentPrefStore.
// This can be used to implement a pref store over a dictionary in the
// PersistentPrefStore.
// For example, consider the following JSON being handled by a JsonPrefStore:
// {
//   "foo": "Hello World",
//   "bar": {
//     "foobar": "Goodbye World"
//   }
// }
//
// A WrapWithPrefixPrefStore can help operate on the dict for "bar", directly.
// That is, any query for "foobar" on this store will correspond to a query for
// "bar.foobar" in the JsonPrefStore.
//
// This is achieved by prefixing all the queries with the provided prefix.
//
// This can be used to merge separate pref stores into one single storage under
// separate dictionary items.
//
// NOTE: Users are responsible for ensuring the prefix is not an existing pref.
class COMPONENTS_PREFS_EXPORT WrapWithPrefixPrefStore
    : public PersistentPrefStore,
      public PrefStore::Observer { … };

#endif  // COMPONENTS_PREFS_WRAP_WITH_PREFIX_PREF_STORE_H_