category_registry.h

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/* -*- Mode: C++; tab-width: 4; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/*
 *     Copyright 2016 Couchbase, Inc
 *
 *   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.
 */
#pragma once

#include <array>
#include <atomic>
#include <mutex>
#include <string>
#include <vector>

#include "phosphor/platform/core.h"

namespace phosphor {

    enum class CategoryStatus : char { Disabled, Enabled };

    using AtomicCategoryStatus = std::atomic<CategoryStatus>;

    // Forward declare
    class StatsCallback;

    class PHOSPHOR_API CategoryRegistry {
    public:
        static constexpr int registry_size = 250;

        CategoryRegistry();

        const AtomicCategoryStatus& getStatus(const char* category_group);

        void updateEnabled(const std::vector<std::string>& enabled,
                           const std::vector<std::string>& disabled);

        void disableAll();

        static CategoryStatus calculateEnabled(
                const std::string& category_group,
                const std::vector<std::string>& enabled,
                const std::vector<std::string>& disabled);

        void getStats(StatsCallback& addStats) const;

    protected:
        CategoryStatus calculateEnabled(size_t index);

        mutable std::mutex mutex;

        std::array<std::string, registry_size> groups;
        static constexpr int index_category_limit = 1;
        static constexpr int index_metadata = 2;
        static constexpr int index_non_default_categories = 3;

        std::array<AtomicCategoryStatus, registry_size> group_statuses;
        std::atomic<size_t> group_count;

        std::vector<std::string> enabled_categories;
        std::vector<std::string> disabled_categories;
    };
}