58 lines
1.7 KiB
PHP
58 lines
1.7 KiB
PHP
<?php
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/******************************************************************************
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* YMS - Yacht Management Software
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* Copyright (C) 2024-2026 Thomas Hooge
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*
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* SPDX-License-Identifier: WTFPL
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******************************************************************************
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*/
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function db_lock_acquire($table, $key, $userid) {
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global $pdo;
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$token = bin2hex(random_bytes(8));
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// first try new lock
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$sql = "INSERT INTO recordlock (lock_table, lock_key, token, userid) "
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. "VALUES (?, ?, ?, ?)";
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try {
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$sth = $pdo->prepare($sql);
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$sth->execute([$table, $key, $token, $userid]);
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return $token;
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} catch (PDOException $e) {
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if ($e->errorInfo[1] != 1062) {
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throw $e;
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}
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}
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// lazy locking: lock exists but is old, so we use it
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$sql = "UPDATE recordlock "
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. "SET token=?, userid=?, "
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. "created_at=CURRENT_TIMESTAMP, last_seen=CURRENT_TIMESTAMP "
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. "WHERE lock_table=? AND lock_key=? "
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. "AND last_seen<CURRENT_TIMESTAMP-INTERVAL 5 MINUTE";
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$sth = $pdo->prepare($sql);
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$sth->execute([$token, $userid, $table, $key]);
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if ($stmt->rowCount() === 1) {
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return $token;
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}
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return null;
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}
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function db_lock_refresh($token) {
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global $pdo;
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$sql = "UPDATE recordlock "
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. "SET last_seen=CURRENT_TIMESTAMP "
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. "WHERE token=?";
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$sth = $pdo->prepare($sql);
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$sth->execute([$token]);
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return $sth->rowCount() === 1;
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}
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function db_lock_release($token) {
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global $pdo;
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$sql = "DELETE FROM recordlock WHERE token=?";
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$sth = $pdo->prepare($sql);
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$sth->execute([$token]);
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return $sth->rowCount() === 1;
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}
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