ActionScheduler_OptionLock.php
| 1 | <?php |
| 2 | |
| 3 | /** |
| 4 | * Provide a way to set simple transient locks to block behaviour |
| 5 | * for up-to a given duration. |
| 6 | * |
| 7 | * Class ActionScheduler_OptionLock |
| 8 | * |
| 9 | * @since 3.0.0 |
| 10 | */ |
| 11 | class ActionScheduler_OptionLock extends ActionScheduler_Lock { |
| 12 | |
| 13 | /** |
| 14 | * Set a lock using options for a given amount of time (60 seconds by default). |
| 15 | * |
| 16 | * Using an autoloaded option avoids running database queries or other resource intensive tasks |
| 17 | * on frequently triggered hooks, like 'init' or 'shutdown'. |
| 18 | * |
| 19 | * For example, ActionScheduler_QueueRunner->maybe_dispatch_async_request() uses a lock to avoid |
| 20 | * calling ActionScheduler_QueueRunner->has_maximum_concurrent_batches() every time the 'shutdown', |
| 21 | * hook is triggered, because that method calls ActionScheduler_QueueRunner->store->get_claim_count() |
| 22 | * to find the current number of claims in the database. |
| 23 | * |
| 24 | * @param string $lock_type A string to identify different lock types. |
| 25 | * @bool True if lock value has changed, false if not or if set failed. |
| 26 | */ |
| 27 | public function set( $lock_type ) { |
| 28 | global $wpdb; |
| 29 | |
| 30 | $lock_key = $this->get_key( $lock_type ); |
| 31 | $existing_lock_value = $this->get_existing_lock( $lock_type ); |
| 32 | $new_lock_value = $this->new_lock_value( $lock_type ); |
| 33 | |
| 34 | // The lock may not exist yet, or may have been deleted. |
| 35 | if ( empty( $existing_lock_value ) ) { |
| 36 | return (bool) $wpdb->insert( |
| 37 | $wpdb->options, |
| 38 | array( |
| 39 | 'option_name' => $lock_key, |
| 40 | 'option_value' => $new_lock_value, |
| 41 | 'autoload' => 'no', |
| 42 | ) |
| 43 | ); |
| 44 | } |
| 45 | |
| 46 | if ( $this->get_expiration_from( $existing_lock_value ) >= time() ) { |
| 47 | return false; |
| 48 | } |
| 49 | |
| 50 | // Otherwise, try to obtain the lock. |
| 51 | return (bool) $wpdb->update( |
| 52 | $wpdb->options, |
| 53 | array( 'option_value' => $new_lock_value ), |
| 54 | array( |
| 55 | 'option_name' => $lock_key, |
| 56 | 'option_value' => $existing_lock_value, |
| 57 | ) |
| 58 | ); |
| 59 | } |
| 60 | |
| 61 | /** |
| 62 | * If a lock is set, return the timestamp it was set to expiry. |
| 63 | * |
| 64 | * @param string $lock_type A string to identify different lock types. |
| 65 | * @return bool|int False if no lock is set, otherwise the timestamp for when the lock is set to expire. |
| 66 | */ |
| 67 | public function get_expiration( $lock_type ) { |
| 68 | return $this->get_expiration_from( $this->get_existing_lock( $lock_type ) ); |
| 69 | } |
| 70 | |
| 71 | /** |
| 72 | * Given the lock string, derives the lock expiration timestamp (or false if it cannot be determined). |
| 73 | * |
| 74 | * @param string $lock_value String containing a timestamp, or pipe-separated combination of unique value and timestamp. |
| 75 | * |
| 76 | * @return false|int |
| 77 | */ |
| 78 | private function get_expiration_from( $lock_value ) { |
| 79 | $lock_string = explode( '|', $lock_value ); |
| 80 | |
| 81 | // Old style lock? |
| 82 | if ( count( $lock_string ) === 1 && is_numeric( $lock_string[0] ) ) { |
| 83 | return (int) $lock_string[0]; |
| 84 | } |
| 85 | |
| 86 | // New style lock? |
| 87 | if ( count( $lock_string ) === 2 && is_numeric( $lock_string[1] ) ) { |
| 88 | return (int) $lock_string[1]; |
| 89 | } |
| 90 | |
| 91 | return false; |
| 92 | } |
| 93 | |
| 94 | /** |
| 95 | * Get the key to use for storing the lock in the transient |
| 96 | * |
| 97 | * @param string $lock_type A string to identify different lock types. |
| 98 | * @return string |
| 99 | */ |
| 100 | protected function get_key( $lock_type ) { |
| 101 | return sprintf( 'action_scheduler_lock_%s', $lock_type ); |
| 102 | } |
| 103 | |
| 104 | /** |
| 105 | * Supplies the existing lock value, or an empty string if not set. |
| 106 | * |
| 107 | * @param string $lock_type A string to identify different lock types. |
| 108 | * |
| 109 | * @return string |
| 110 | */ |
| 111 | private function get_existing_lock( $lock_type ) { |
| 112 | global $wpdb; |
| 113 | |
| 114 | // Now grab the existing lock value, if there is one. |
| 115 | return (string) $wpdb->get_var( |
| 116 | $wpdb->prepare( |
| 117 | "SELECT option_value FROM $wpdb->options WHERE option_name = %s", |
| 118 | $this->get_key( $lock_type ) |
| 119 | ) |
| 120 | ); |
| 121 | } |
| 122 | |
| 123 | /** |
| 124 | * Supplies a lock value consisting of a unique value and the current timestamp, which are separated by a pipe |
| 125 | * character. |
| 126 | * |
| 127 | * Example: (string) "649de012e6b262.09774912|1688068114" |
| 128 | * |
| 129 | * @param string $lock_type A string to identify different lock types. |
| 130 | * |
| 131 | * @return string |
| 132 | */ |
| 133 | private function new_lock_value( $lock_type ) { |
| 134 | return uniqid( '', true ) . '|' . ( time() + $this->get_duration( $lock_type ) ); |
| 135 | } |
| 136 | } |
| 137 |