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// Copyright 2021 The Cobalt Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Module Overview: Starboard Once module
//
// Onces represent initializations that should only ever happen once per
// process, in a thread-safe way.
#ifndef STARBOARD_SHARED_LINUX_SINGLETON_H_
#define STARBOARD_SHARED_LINUX_SINGLETON_H_
#include "starboard/once.h"
#include "starboard/shared/internal_only.h"
namespace starboard {
// Singleton helper class.
template <typename Type>
class Singleton {
public:
Singleton() {}
// This helper class assumes that Type has a function
// "bool Initialize();" that returns false when
// initialization fails.
static Type* GetOrCreateInstance() {
static SbOnceControl s_once_flag = SB_ONCE_INITIALIZER;
static Type* s_singleton = NULL;
struct Local {
static void Init() {
Type* singleton = new Type();
if (singleton && singleton->Type::Initialize()) {
s_singleton = singleton;
}
}
};
SbOnce(&s_once_flag, Local::Init);
return s_singleton;
}
// Prevent copying and moving.
Singleton(Singleton const&) = delete;
Singleton& operator=(const Singleton&) = delete;
// Prevent deleting.
void operator delete(void* p) = delete;
protected:
// Prevent destroying.
~Singleton();
};
} // namespace starboard
#endif // STARBOARD_SHARED_LINUX_SINGLETON_H_