cs\DB

Complexity

Total Complexity

30

Size/Duplication

Total Lines	241
Duplicated Lines	0 %

Coupling/Cohesion

Components	1
Dependencies	5

Test Coverage

Coverage

100%

Importance

Changes

0

8 Methods

Rating	Name	Duplication	Size	Complexity
A	get_connections_list()	0	3	1
A	queries()	0	13	3
A	time()	0	13	3
A	db()	0	3	1
A	db_prime()	0	3	1
C	connect()	0	71	12
B	get_db_connection_settings()	0	30	3
B	choose_mirror()	0	25	6

<?php
/**
 * @package   CleverStyle Framework
 * @author    Nazar Mokrynskyi <nazar@mokrynskyi.com>
 * @copyright Copyright (c) 2011-2016, Nazar Mokrynskyi
 * @license   MIT License, see license.txt
 */
namespace cs;

/**
 * @method static $this instance($check = false)
 */
class DB {
	use
		Singleton;
	const CONNECTIONS_MASTER        = 0;
	const CONNECTIONS_MIRROR        = 1;
	const CONNECTIONS_SUCCESSFUL    = 2;
	const CONNECTIONS_FAILED        = 3;
	const MASTER_MIRROR             = -1;
	const MIRROR_MODE_MASTER_MASTER = 0;
	const MIRROR_MODE_MASTER_SLAVE  = 1;
	/**
	 * @var array[]
	 */
	protected $connections = [
		self::CONNECTIONS_MASTER     => [],
		self::CONNECTIONS_MIRROR     => [],
		self::CONNECTIONS_SUCCESSFUL => [],
		self::CONNECTIONS_FAILED     => [],
	];
	/**
	 * Get list of connections of specified type
	 *
	 * @param int $type One of constants `self::CONNECTIONS_*`
	 *
	 * @return array For `self::CONNECTIONS_MASTER` and `self::CONNECTIONS_MIRRORS` array of successful connections with corresponding objects as values of
	 *               array, otherwise array where keys are database ids and values are strings with information about database
	 */
	public function get_connections_list ($type) {
		return $this->connections[$type];
	}
	/**
	 * Total number of executed queries
	 *
	 * @return int
	 */
	public function queries () {
		$queries = 0;
		/**
		 * @var DB\_Abstract $c
		 */
		foreach ($this->connections[self::CONNECTIONS_MASTER] as $c) {
			$queries += $c->queries_count();
		}
		foreach ($this->connections[self::CONNECTIONS_MIRROR] as $c) {
			$queries += $c->queries_count();
		}
		return $queries;
	}
	/**
	 * Total time spent on all queries and connections
	 *
	 * @return float
	 */
	public function time () {
		$time = 0;
		/**
		 * @var DB\_Abstract $c
		 */
		foreach ($this->connections[self::CONNECTIONS_MASTER] as $c) {
			$time += $c->connecting_time() + $c->time();
		}
		foreach ($this->connections[self::CONNECTIONS_MIRROR] as $c) {
			$time += $c->connecting_time() + $c->time();
		}
		return $time;
	}
	/**
	 * Get database instance for read queries
	 *
	 * @param int $database_id
	 *
	 * @return DB\_Abstract|False_class Returns instance of False_class on failure
	 *
	 * @throws ExitException
	 */
	public function db ($database_id) {
		return $this->connect($database_id, true);
	}
	/**
	 * Get database instance for write queries
	 *
	 * @param int $database_id
	 *
	 * @return DB\_Abstract|False_class Returns instance of False_class on failure
	 *
	 * @throws ExitException
	 */
	public function db_prime ($database_id) {
		return $this->connect($database_id, false);
	}
	/**
	 * @param int  $database_id
	 * @param bool $read_query
	 *
	 * @return DB\_Abstract|False_class
	 *
	 * @throws ExitException
	 */
	protected function connect ($database_id, $read_query) {
		$database_id = (int)$database_id;
		/**
		 * If connection found in list of failed connections - return instance of False_class
		 */
		if (isset($this->connections[self::CONNECTIONS_FAILED][$database_id])) {
			return False_class::instance();
		}
		/**
		 * If connection to DB mirror already established
		 */
		if (
			$read_query &&
			isset($this->connections[self::CONNECTIONS_MIRROR][$database_id])
		) {
			return $this->connections[self::CONNECTIONS_MIRROR][$database_id];
		}
		/**
		 * If connection already established
		 */
		if (isset($this->connections[self::CONNECTIONS_MASTER][$database_id])) {
			return $this->connections[self::CONNECTIONS_MASTER][$database_id];
		}
		$Core = Core::instance();
		/**
		 * Try to connect second time if first time fails, probably, to another mirror
		 */
		for ($trial = 0; $trial < 2; ++$trial) {
			list($database_settings, $is_mirror) = $this->get_db_connection_settings($database_id, $read_query);
			/**
			 * Establish new connection
			 *
			 * @var DB\_Abstract $connection
			 */
			$engine_class    = "cs\\DB\\$database_settings[type]";
			$connection      = new $engine_class(
				$database_settings['name'],
				$database_settings['user'],
				$database_settings['password'],
				$database_settings['host'],
				$database_settings['prefix']
			);
			$connection_name = ($database_id == 0 ? "Core DB ($Core->db_type)" : $database_id)."/$database_settings[host]/$database_settings[type]";
			unset($engine_class, $database_settings);
			/**
			 * If successfully - add connection to the list of success connections and return instance of DB engine object
			 */
			if (is_object($connection) && $connection->connected()) {
				$this->connections[self::CONNECTIONS_SUCCESSFUL][] = $connection_name;
				if ($is_mirror) {
					$this->connections[self::CONNECTIONS_MIRROR][$database_id] = $connection;
				} else {
					$this->connections[self::CONNECTIONS_MASTER][$database_id] = $connection;
				}
				return $connection;
			}
		}
		/**
		 * If failed - add connection to the list of failed connections and log error
		 */
		/** @noinspection PhpUndefinedVariableInspection */
		$this->connections[self::CONNECTIONS_FAILED][$database_id] = $connection_name;
		trigger_error(
			$database_id == 0 ? 'Error connecting to core DB of site' : "Error connecting to DB $connection_name",
			E_USER_WARNING
		);
		if ($database_id == 0) {
			throw new ExitException('Error connecting to core DB of site', 500);
		}
		return False_class::instance();
	}
	/**
	 * Get database connection settings, depending on query type and system configuration settings of main db or one of mirrors might be returned
	 *
	 * @param int  $database_id
	 * @param bool $read_query
	 *
	 * @return array
	 */
	protected function get_db_connection_settings ($database_id, $read_query) {
		$Config = Config::instance();
		$Core   = Core::instance();
		/**
		 * Choose right mirror depending on system configuration
		 */
		$is_mirror    = false;
		$mirror_index = $this->choose_mirror($database_id, $read_query);
		if ($mirror_index === self::MASTER_MIRROR) {
			if ($database_id == 0) {
				$database_settings = [
					'type'     => $Core->db_type,
					'name'     => $Core->db_name,
					'user'     => $Core->db_user,
					'password' => $Core->db_password,
					'host'     => $Core->db_host,
					'prefix'   => $Core->db_prefix
				];
			} else {
				$database_settings = $Config->db[$database_id];
			}
		} else {
			$database_settings = $Config->db[$database_id]['mirrors'][$mirror_index];
			$is_mirror         = true;
		}
		return [
			$database_settings,
			$is_mirror
		];
	}
	/**
	 * Choose index of DB mirrors among available
	 *
	 * @param int  $database_id
	 * @param bool $read_query
	 *
	 * @return int
	 */
	protected function choose_mirror ($database_id, $read_query = true) {
		$Config = Config::instance(true);
		/**
		 * $Config might not be initialized yet
		 */
		if (
			!@$Config->core['db_balance'] ||
			!isset($Config->db[$database_id]['mirrors'][0])
		) {
			return self::MASTER_MIRROR;
		}
		$mirrors_count = count($Config->db[$database_id]['mirrors']);
		/**
		 * Main db should be excluded from read requests if writes to mirrors are not allowed
		 */
		$selected_mirror = mt_rand(
			0,
			$read_query && $Config->core['db_mirror_mode'] == self::MIRROR_MODE_MASTER_SLAVE ? $mirrors_count - 1 : $mirrors_count
		);
		/**
		 * Main DB assumed to be in the end of interval, that is why `$select_mirror < $mirrors_count` will correspond to one of available mirrors,
		 * and `$select_mirror == $mirrors_count` to master DB itself
		 */
		return $selected_mirror < $mirrors_count ? $selected_mirror : self::MASTER_MIRROR;
	}
}