Zabbix

/*

** Copyright (C) 2001-2024 Zabbix SIA

**

** This program is free software: you can redistribute it and/or modify it under the terms of

** the GNU Affero General Public License as published by the Free Software Foundation, version 3.

**

** This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;

** without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

** See the GNU Affero General Public License for more details.

**

** You should have received a copy of the GNU Affero General Public License along with this program.

** If not, see <https://www.gnu.org/licenses/>.

**/

​

​

class CEventHub {

​

    #subscribers = new Map();

​

    #latest_data = new Map();

​

    publish({data, descriptor}) {

        descriptor = Object.keys(descriptor).sort().reduce(

            (descriptor_sorted, key) => {

                descriptor_sorted[key] = descriptor[key];

​

                return descriptor_sorted;

            },

            {}

        );

​

        const descriptor_hash = JSON.stringify(descriptor);

​

        this.#latest_data.delete(descriptor_hash);

        this.#latest_data.set(descriptor_hash, {data, descriptor});

​

        for (const {require, callback} of this.#subscribers.values()) {

            if (CEventHub.#match(require, descriptor)) {

                callback({data, descriptor});

            }

        }

    }

​

    subscribe({require = {}, callback}) {

        for (const {data, descriptor} of [...this.#latest_data.values()].reverse()) {

            if (CEventHub.#match(require, descriptor)) {

                callback({data, descriptor});

​

                break;

            }

        }

​

        const subscription = {};

​

        this.#subscribers.set(subscription, {require, callback});

​

        return subscription;

    }

​

    unsubscribe(subscription) {

        return this.#subscribers.delete(subscription);

    }

​

    getData(require) {

        for (const {data, descriptor} of [...this.#latest_data.values()].reverse()) {

            if (CEventHub.#match(require, descriptor)) {

                return data;

            }

        }

​

        return undefined;

    }

​

    invalidateData(require) {

        for (const [descriptor_hash, {descriptor}] of this.#latest_data.entries()) {

            if (CEventHub.#match(require, descriptor)) {

                this.#latest_data.delete(descriptor_hash);

            }

        }

    }

​

    static #match(require, descriptor) {

        for (const [key, value] of Object.entries(require)) {

            if (!(key in descriptor) || descriptor[key] !== value) {

                return false;

            }

        }

​

        return true;

    }

}