Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
Complex classes like Give_Logging often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use Give_Logging, and based on these observations, apply Extract Interface, too.
| 1 | <?php  | 
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| 24 | class Give_Logging { | 
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| 25 | /**  | 
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| 26 | * Logs data operation handler object.  | 
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| 27 | *  | 
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| 28 | * @since 2.0  | 
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| 29 | * @access private  | 
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| 30 | * @var Give_DB_Logs  | 
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| 31 | 6 | */  | 
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| 32 | public $log_db;  | 
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| 33 | 6 | ||
| 34 | /**  | 
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| 35 | * Log meta data operation handler object.  | 
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| 36 | 6 | *  | 
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| 37 | * @since 2.0  | 
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| 38 | 6 | * @access private  | 
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| 39 | * @var Give_DB_Log_Meta  | 
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| 40 | */  | 
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| 41 | public $logmeta_db;  | 
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| 42 | |||
| 43 | /**  | 
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| 44 | * Class Constructor  | 
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| 45 | *  | 
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| 46 | * Set up the Give Logging Class.  | 
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| 47 | 6 | *  | 
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| 48 | * @since 1.0  | 
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| 49 | * @access public  | 
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| 50 | 6 | */  | 
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| 51 | 6 | 	public function __construct() { | 
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| 82 | |||
| 83 | |||
| 84 | /**  | 
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| 85 | * Log Post Type  | 
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| 86 | *  | 
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| 87 | 55 | * Registers the 'give_log' Post Type.  | 
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| 88 | *  | 
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| 89 | 55 | * @since 1.0  | 
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| 90 | 55 | * @access public  | 
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| 91 | *  | 
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| 92 | 55 | * @return void  | 
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| 93 | */  | 
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| 94 | 55 | 	public function register_post_type() { | 
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| 113 | |||
| 114 | /**  | 
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| 115 | * Log Type Taxonomy  | 
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| 116 | *  | 
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| 117 | * Registers the "Log Type" taxonomy. Used to determine the type of log entry.  | 
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| 118 | *  | 
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| 119 | * @since 1.0  | 
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| 120 | * @access public  | 
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| 121 | *  | 
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| 122 | * @return void  | 
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| 123 | */  | 
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| 124 | 	public function register_taxonomy() { | 
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| 129 | |||
| 130 | /**  | 
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| 131 | 1 | * Log Types  | 
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| 132 | *  | 
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| 133 | 1 | * Sets up the default log types and allows for new ones to be created.  | 
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| 134 | 1 | *  | 
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| 135 | 1 | * @since 1.0  | 
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| 136 | * @access public  | 
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| 137 | 1 | *  | 
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| 138 | * @return array $terms  | 
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| 139 | 1 | */  | 
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| 140 | 	public function log_types() { | 
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| 150 | |||
| 151 | /**  | 
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| 152 | * Check if a log type is valid  | 
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| 153 | *  | 
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| 154 | * Checks to see if the specified type is in the registered list of types.  | 
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| 155 | 1 | *  | 
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| 156 | 1 | * @since 1.0  | 
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| 157 | 1 | * @access public  | 
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| 158 | 1 | *  | 
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| 159 | * @param string $type Log type.  | 
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| 160 | 1 | *  | 
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| 161 | * @return bool Whether log type is valid.  | 
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| 162 | */  | 
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| 163 | 	public function valid_type( $type ) { | 
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| 166 | |||
| 167 | /**  | 
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| 168 | * Create new log entry  | 
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| 169 | *  | 
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| 170 | * This is just a simple and fast way to log something. Use $this->insert_log()  | 
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| 171 | * if you need to store custom meta data.  | 
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| 172 | *  | 
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| 173 | * @since 1.0  | 
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| 174 | * @access public  | 
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| 175 | 43 | *  | 
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| 176 | * @param string $title Log entry title. Default is empty.  | 
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| 177 | 43 | * @param string $message Log entry message. Default is empty.  | 
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| 178 | 43 | * @param int $parent Log entry parent. Default is 0.  | 
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| 179 | 43 | * @param string $type Log type. Default is empty string.  | 
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| 180 | 43 | *  | 
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| 181 | * @return int Log ID.  | 
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| 182 | 43 | */  | 
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| 183 | 	public function add( $title = '', $message = '', $parent = 0, $type = '' ) { | 
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| 193 | 43 | ||
| 194 | 43 | /**  | 
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| 195 | * Get Logs  | 
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| 196 | *  | 
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| 197 | 43 | * Retrieves log items for a particular object ID.  | 
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| 198 | 42 | *  | 
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| 199 | 42 | * @since 1.0  | 
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| 200 | 42 | * @access public  | 
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| 201 | 42 | *  | 
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| 202 | * @param int $object_id Log object ID. Default is 0.  | 
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| 203 | 43 | * @param string $type Log type. Default is empty string.  | 
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| 204 | * @param int $paged Page number Default is null.  | 
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| 205 | 43 | *  | 
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| 206 | * @return array An array of the connected logs.  | 
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| 207 | */  | 
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| 208 | 	public function get_logs( $object_id = 0, $type = '', $paged = null ) { | 
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| 215 | |||
| 216 | /**  | 
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| 217 | * Stores a log entry  | 
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| 218 | *  | 
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| 219 | * @since 1.0  | 
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| 220 | * @access public  | 
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| 221 | *  | 
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| 222 | * @param array $log_data Log entry data.  | 
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| 223 | * @param array $log_meta Log entry meta.  | 
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| 224 | *  | 
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| 225 | * @return int The ID of the newly created log item.  | 
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| 226 | */  | 
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| 227 | 	public function insert_log( $log_data = array(), $log_meta = array() ) { | 
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| 271 | |||
| 272 | 1 | /**  | 
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| 273 | 1 | * Update and existing log item  | 
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| 274 | 1 | *  | 
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| 275 | 1 | * @since 1.0  | 
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| 276 | 1 | * @access public  | 
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| 277 | 1 | *  | 
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| 278 | * @param array $log_data Log entry data.  | 
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| 279 | 1 | * @param array $log_meta Log entry meta.  | 
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| 280 | *  | 
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| 281 | 1 | * @return bool|null True if successful, false otherwise.  | 
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| 282 | 1 | */  | 
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| 283 | 	public function update_log( $log_data = array(), $log_meta = array() ) { | 
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| 342 | |||
| 343 | /**  | 
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| 344 | * Retrieve all connected logs  | 
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| 345 | *  | 
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| 346 | * Used for retrieving logs related to particular items, such as a specific donation.  | 
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| 347 | * For new table params check: Give_DB_Logs::get_column_defaults and Give_DB_Logs::get_sql#L262  | 
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| 348 | 32 | *  | 
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| 349 | * @since 1.0  | 
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| 350 | 32 | * @since 2.0 Added new table logic.  | 
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| 351 | 32 | * @access public  | 
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| 352 | 32 | *  | 
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| 353 | 32 | * @param array $args Query arguments.  | 
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| 354 | *  | 
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| 355 | 32 | * @return array|false Array if logs were found, false otherwise.  | 
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| 356 | */  | 
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| 357 | 32 | 	public function get_connected_logs( $args = array() ) { | 
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| 382 | |||
| 383 | /**  | 
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| 384 | * Retrieve Log Count  | 
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| 385 | *  | 
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| 386 | * Retrieves number of log entries connected to particular object ID.  | 
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| 387 | *  | 
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| 388 | * @since 1.0  | 
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| 389 | * @access public  | 
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| 390 | *  | 
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| 391 | * @param int $object_id Log object ID. Default is 0.  | 
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| 392 | * @param string $type Log type. Default is empty string.  | 
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| 393 | * @param array $meta_query Log meta query. Default is null.  | 
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| 394 | * @param array $date_query Log data query. Default is null.  | 
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| 395 | *  | 
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| 396 | * @return int Log count.  | 
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| 397 | */  | 
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| 398 | 	public function get_log_count( $object_id = 0, $type = '', $meta_query = null, $date_query = null ) { | 
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| 437 | |||
| 438 | /**  | 
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| 439 | * Delete Logs  | 
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| 440 | *  | 
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| 441 | * Remove log entries connected to particular object ID.  | 
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| 442 | *  | 
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| 443 | * @since 1.0  | 
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| 444 | * @access public  | 
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| 445 | *  | 
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| 446 | * @param int $object_id Log object ID. Default is 0.  | 
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| 447 | * @param string $type Log type. Default is empty string.  | 
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| 448 | * @param array $meta_query Log meta query. Default is null.  | 
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| 449 | *  | 
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| 450 | * @return void  | 
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| 451 | */  | 
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| 452 | 	public function delete_logs( $object_id = 0, $type = '', $meta_query = null ) { | 
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| 496 | |||
| 497 | /**  | 
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| 498 | * Setup cron to delete log cache in background.  | 
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| 499 | *  | 
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| 500 | * @since 1.7  | 
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| 501 | * @access public  | 
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| 502 | *  | 
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| 503 | * @param int $post_id  | 
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| 504 | */  | 
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| 505 | 	public function background_process_delete_cache( $post_id ) { | 
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| 509 | |||
| 510 | /**  | 
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| 511 | * Delete all logging cache when form, log or payment updates  | 
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| 512 | *  | 
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| 513 | * @since 1.7  | 
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| 514 | * @access public  | 
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| 515 | *  | 
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| 516 | * @return bool  | 
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| 517 | */  | 
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| 518 | 	public function delete_cache() { | 
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| 532 | |||
| 533 | /**  | 
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| 534 | * Validate query params.  | 
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| 535 | *  | 
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| 536 | * @since 2.0  | 
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| 537 | * @access private  | 
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| 538 | *  | 
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| 539 | * @param array $log_query  | 
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| 540 | * @param array $log_meta  | 
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| 541 | */  | 
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| 542 | 	private function bc_200_validate_params( &$log_query, &$log_meta = array() ) { | 
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| 634 | |||
| 635 | /**  | 
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| 636 | * Set new log properties.  | 
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| 637 | *  | 
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| 638 | * @since 2.0  | 
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| 639 | * @access private  | 
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| 640 | *  | 
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| 641 | * @param array $logs  | 
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| 642 | */  | 
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| 643 | 	private function bc_200_add_new_properties( &$logs ) { | 
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| 686 | |||
| 687 | /**  | 
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| 688 | * Change log parent to payment if set to form.  | 
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| 689 | *  | 
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| 690 | * @since 2.0  | 
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| 691 | * @access public  | 
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| 692 | *  | 
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| 693 | * @param mixed $check  | 
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| 694 | * @param int $log_id  | 
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| 695 | * @param array $meta_key  | 
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| 696 | * @param array $meta_value  | 
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| 697 | *  | 
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| 698 | * @return mixed  | 
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| 699 | */  | 
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| 700 | 	public function bc_200_set_payment_as_log_parent( $check, $log_id, $meta_key, $meta_value ) { | 
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| 746 | }  | 
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| 747 | 
This check looks for variable assignements that are either overwritten by other assignments or where the variable is not used subsequently.
Both the
$myVarassignment in line 1 and the$higherassignment in line 2 are dead. The first because$myVaris never used and the second because$higheris always overwritten for every possible time line.