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// 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 {
public:
WrapWithPrefixPrefStore(scoped_refptr<PersistentPrefStore> target_pref_store,
std::string_view path_prefix);
WrapWithPrefixPrefStore(const WrapWithPrefixPrefStore&) = delete;
WrapWithPrefixPrefStore& operator=(const WrapWithPrefixPrefStore&) = delete;
// PrefStore implementation.
bool GetValue(std::string_view key,
const base::Value** result) const override;
base::Value::Dict GetValues() const override;
void AddObserver(PrefStore::Observer* observer) override;
void RemoveObserver(PrefStore::Observer* observer) override;
bool HasObservers() const override;
bool IsInitializationComplete() const override;
// PersistentPrefStore implementation.
bool GetMutableValue(std::string_view key, base::Value** result) override;
void ReportValueChanged(std::string_view key, uint32_t flags) override;
void SetValue(std::string_view key,
base::Value value,
uint32_t flags) override;
void SetValueSilently(std::string_view key,
base::Value value,
uint32_t flags) override;
void RemoveValue(std::string_view key, uint32_t flags) override;
bool ReadOnly() const override;
PrefReadError GetReadError() const override;
PersistentPrefStore::PrefReadError ReadPrefs() override;
void ReadPrefsAsync(ReadErrorDelegate* error_delegate) override;
void SchedulePendingLossyWrites() override;
void OnStoreDeletionFromDisk() override;
void RemoveValuesByPrefixSilently(std::string_view prefix) override;
bool HasReadErrorDelegate() const override;
// PrefStore::Observer implementation.
void OnPrefValueChanged(std::string_view key) override;
void OnInitializationCompleted(bool succeeded) override;
protected:
~WrapWithPrefixPrefStore() override;
private:
std::string AddDottedPrefix(std::string_view path) const;
std::string_view RemoveDottedPrefix(std::string_view path) const;
bool HasDottedPrefix(std::string_view path) const;
scoped_refptr<PersistentPrefStore> target_pref_store_;
const std::string dotted_prefix_;
base::ObserverList<PrefStore::Observer, true> observers_;
// Optional so we can differentiate `nullopt` from `nullptr`.
std::optional<std::unique_ptr<PersistentPrefStore::ReadErrorDelegate>>
read_error_delegate_;
};
#endif // COMPONENTS_PREFS_WRAP_WITH_PREFIX_PREF_STORE_H_
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