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// Copyright 2025 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CHROME_BROWSER_UI_UNOWNED_USER_DATA_SCOPED_UNOWNED_USER_DATA_H_
#define CHROME_BROWSER_UI_UNOWNED_USER_DATA_SCOPED_UNOWNED_USER_DATA_H_
#include "base/memory/raw_ptr.h"
#include "base/memory/raw_ref.h"
#include "base/types/pass_key.h"
class UnownedUserDataHost;
namespace internal {
// Internal base class for handling setting / unsetting the UnownedUserData
// on the UnownedUserDataHost. Should not be used directly outside of this
// file.
class ScopedUnownedUserDataBase {
protected:
ScopedUnownedUserDataBase(UnownedUserDataHost& host,
const char* key,
void* data);
virtual ~ScopedUnownedUserDataBase();
static void* GetInternal(UnownedUserDataHost& host, const char* key);
private:
using PassKey = base::PassKey<ScopedUnownedUserDataBase>;
raw_ref<UnownedUserDataHost> host_;
const char* key_;
raw_ptr<void> data_;
};
} // namespace internal
// A scoped class to set and unset an UnownedUserData entry on an
// UnownedUserDataHost.
//
// Example Usage:
// class MyFeature {
// public:
// static const char* kDataKey;
//
// explicit MyFeature(UnownedUserDataHost& host)
// : scoped_data_holder_(host) {}
//
// static MyFeature* FromHost(UnownedUserDataHost& host) {
// return ScopedUnownedUserData<MyFeature>::Get(host);
// }
//
// private:
// ScopedUnowneduserData<MyFeature> scoped_data_holder_;
// };
//
// const char* MyFeature::kDataKey = "MyFeature";
//
// Note: See also UnownedUserDataInterface, if you prefer an inheritance pattern
// and want slightly less boilerplate.
template <class T>
class ScopedUnownedUserData : public internal::ScopedUnownedUserDataBase {
public:
ScopedUnownedUserData(UnownedUserDataHost& host, T* data)
: ScopedUnownedUserDataBase(host, T::kDataKey, data) {}
~ScopedUnownedUserData() override = default;
static T* Get(UnownedUserDataHost& host) {
return static_cast<T*>(GetInternal(host, T::kDataKey));
}
};
#endif // CHROME_BROWSER_UI_UNOWNED_USER_DATA_SCOPED_UNOWNED_USER_DATA_H_
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