Complex classes like Scheduled_Backup 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 Scheduled_Backup, and based on these observations, apply Extract Interface, too.
| 1 | <?php  | 
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| 13 | class Scheduled_Backup { | 
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| 14 | |||
| 15 | /**  | 
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| 16 | * The unique schedule id  | 
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| 17 | *  | 
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| 18 | * @var string  | 
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| 19 | * @access private  | 
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| 20 | */  | 
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| 21 | private $id = '';  | 
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| 22 | |||
| 23 | /**  | 
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| 24 | * The slugified version of the schedule name  | 
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| 25 | *  | 
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| 26 | * @var string  | 
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| 27 | * @access private  | 
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| 28 | */  | 
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| 29 | private $slug = '';  | 
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| 30 | |||
| 31 | /**  | 
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| 32 | * The raw schedule options from the database  | 
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| 33 | *  | 
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| 34 | * @var array  | 
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| 35 | * @access private  | 
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| 36 | */  | 
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| 37 | private $options = array(  | 
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| 38 | 'max_backups' => 3,  | 
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| 39 | 'excludes' => array(),  | 
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| 40 | 'type' => 'complete',  | 
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| 41 | 'reoccurrence' => 'manually'  | 
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| 42 | );  | 
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| 43 | |||
| 44 | /**  | 
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| 45 | * Setup the schedule object  | 
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| 46 | * Loads the options from the database and populates properties  | 
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| 47 | *  | 
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| 48 | * @param string $id  | 
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| 49 | *  | 
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| 50 | * @throws Exception  | 
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| 51 | */  | 
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| 52 | |||
| 53 | 	public function __construct( $id ) { | 
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| 54 | |||
| 55 | // Verify the schedule id  | 
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| 56 | 		if ( ! is_string( $id ) || ! trim( $id ) ) { | 
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| 57 | throw new \Exception( 'Argument 1 for ' . __METHOD__ . ' must be a non-empty string' );  | 
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| 58 | }  | 
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| 59 | |||
| 60 | // Store id for later  | 
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| 61 | $this->id = $id;  | 
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| 62 | |||
| 63 | // Load the options  | 
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| 64 | $this->options = array_merge( $this->options, array_filter( (array) get_option( 'hmbkp_schedule_' . $this->get_id() ) ) );  | 
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| 65 | |||
| 66 | 		if ( defined( 'HMBKP_SCHEDULE_START_TIME' ) && strtotime( 'HMBKP_SCHEDULE_START_TIME' ) ) { | 
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| 67 | $this->set_schedule_start_time( strtotime( 'HMBKP_SCHEDULE_START_TIME' ) );  | 
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| 68 | }  | 
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| 69 | |||
| 70 | // Setup the schedule if it isn't set  | 
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| 71 | 		if ( ( ! $this->is_cron_scheduled() && $this->get_reoccurrence() !== 'manually' ) ) { | 
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| 72 | $this->schedule();  | 
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| 73 | }  | 
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| 74 | |||
| 75 | $this->backup_filename = implode( '-', array(  | 
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| 76 | sanitize_title( str_ireplace( array(  | 
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| 77 | 'http://',  | 
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| 78 | 'https://',  | 
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| 79 | 'www'  | 
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| 80 | ), '', home_url() ) ),  | 
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| 81 | $this->get_id(),  | 
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| 82 | $this->get_type(),  | 
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| 83 | current_time( 'Y-m-d-H-i-s' )  | 
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| 84 | ) ) . '.zip';  | 
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| 85 | |||
| 86 | $this->database_dump_filename = implode( '-', array(  | 
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| 87 | 'database',  | 
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| 88 | sanitize_title( str_ireplace( array( 'http://', 'https://', 'www' ), '', home_url() ) ),  | 
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| 89 | $this->get_id()  | 
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| 90 | ) ) . '.sql';  | 
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| 91 | |||
| 92 | $this->status = new Backup_Status( $this->get_id() );  | 
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| 93 | |||
| 94 | }  | 
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| 95 | |||
| 96 | /**  | 
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| 97 | * Get the id for this schedule  | 
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| 98 | */  | 
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| 99 | 	public function get_id() { | 
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| 102 | |||
| 103 | /**  | 
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| 104 | * Get a slugified version of name  | 
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| 105 | */  | 
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| 106 | 	public function get_slug() { | 
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| 107 | |||
| 108 | // We cache slug in $this to save expensive calls to sanitize_title  | 
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| 109 | 		if ( ! empty( $this->slug ) ) { | 
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| 110 | return $this->slug;  | 
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| 111 | }  | 
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| 112 | |||
| 113 | return $this->slug = sanitize_title( $this->get_name() );  | 
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| 114 | |||
| 115 | }  | 
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| 116 | |||
| 117 | /**  | 
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| 118 | * Returns the given option value  | 
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| 119 | *  | 
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| 120 | * @param $option_name  | 
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| 121 | * @return mixed The option value  | 
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| 122 | */  | 
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| 123 | 	public function get_schedule_option( $option_name ) { | 
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| 124 | 		if ( isset( $this->options[ $option_name ] ) ) { | 
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| 125 | return $this->options[ $option_name ];  | 
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| 126 | }  | 
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| 127 | }  | 
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| 128 | |||
| 129 | /**  | 
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| 130 | * Get the name of this backup schedule  | 
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| 131 | *  | 
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| 132 | * @return string  | 
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| 133 | */  | 
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| 134 | 	public function get_name() { | 
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| 137 | |||
| 138 | /**  | 
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| 139 | * Get the type of backup  | 
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| 140 | *  | 
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| 141 | * @return string  | 
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| 142 | */  | 
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| 143 | 	public function get_type() { | 
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| 146 | |||
| 147 | /**  | 
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| 148 | * Set the type of backup  | 
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| 149 | *  | 
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| 150 | * @param string $type  | 
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| 151 | */  | 
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| 152 | 	public function set_type( $type ) { | 
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| 153 | 		if ( ! isset( $this->options['type'] ) || $this->options['type'] !== $type ) { | 
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| 154 | $this->options['type'] = $type;  | 
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| 155 | }  | 
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| 156 | }  | 
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| 157 | |||
| 158 | /**  | 
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| 159 | * Get the exclude rules  | 
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| 160 | *  | 
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| 161 | * @return array  | 
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| 162 | */  | 
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| 163 | 	public function get_excludes() { | 
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| 166 | |||
| 167 | /**  | 
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| 168 | * Set the exclude rules  | 
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| 169 | *  | 
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| 170 | * @param mixed $excludes A comma separated list or array of exclude rules  | 
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| 171 | * @param bool $append Whether to replace or append to existing rules  | 
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| 172 | *  | 
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| 173 | * @return string  | 
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| 174 | */  | 
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| 175 | 	public function set_excludes( $exclude_rules, $append = false ) { | 
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| 176 | |||
| 177 | // Normalize the exclude rules before we save them  | 
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| 178 | $excludes = new Excludes;  | 
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| 179 | $excludes = $excludes->normalize( (array) $exclude_rules );  | 
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| 180 | |||
| 181 | // If these are valid excludes and they are different save them  | 
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| 182 | 		if ( empty( $this->options['excludes'] ) || $this->options['excludes'] !== $excludes ) { | 
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| 183 | $this->options['excludes'] = $append && ! empty( $this->options['excludes'] ) ? array_merge( (array) $this->options['excludes'], (array) $excludes ) : (array) $excludes;  | 
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| 184 | }  | 
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| 185 | |||
| 186 | }  | 
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| 187 | |||
| 188 | /**  | 
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| 189 | * Get the maximum number of backups to keep  | 
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| 190 | *  | 
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| 191 | * @return int  | 
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| 192 | */  | 
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| 193 | 	public function get_max_backups() { | 
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| 196 | |||
| 197 | /**  | 
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| 198 | * Set the maximum number of backups to keep  | 
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| 199 | *  | 
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| 200 | * @param int $max  | 
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| 201 | *  | 
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| 202 | * @return WP_Error|boolean  | 
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| 203 | */  | 
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| 204 | 	public function set_max_backups( $max ) { | 
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| 207 | |||
| 208 | 	public function get_status() { | 
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| 211 | |||
| 212 | /**  | 
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| 213 | * Back compat with old set_status mathod  | 
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| 214 | *  | 
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| 215 | * @deprecated 3.4 Backup->status->set_status()  | 
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| 216 | */  | 
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| 217 | 	public function set_status( $message ) { | 
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| 221 | |||
| 222 | /**  | 
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| 223 | * Get the array of services options for this schedule  | 
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| 224 | *  | 
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| 225 | * @param $service  | 
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| 226 | * @param null $option  | 
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| 227 | *  | 
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| 228 | * @return array  | 
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| 229 | */  | 
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| 230 | 	public function get_service_options( $service, $option = null ) { | 
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| 249 | |||
| 250 | /**  | 
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| 251 | * Set the service options for this schedule  | 
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| 252 | *  | 
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| 253 | * @param $service  | 
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| 254 | * @param array $options  | 
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| 255 | */  | 
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| 256 | 	public function set_service_options( $service, Array $options ) { | 
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| 259 | |||
| 260 | /**  | 
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| 261 | * Get the start time for the schedule  | 
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| 262 | *  | 
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| 263 | * @return int timestamp || 0 for manual only schedules  | 
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| 264 | */  | 
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| 265 | 	public function get_schedule_start_time( $gmt = true ) { | 
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| 286 | |||
| 287 | /**  | 
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| 288 | * Set the schedule start time.  | 
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| 289 | *  | 
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| 290 | * @param timestamp $time  | 
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| 291 | */  | 
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| 292 | 	public function set_schedule_start_time( $time ) { | 
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| 299 | |||
| 300 | /**  | 
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| 301 | * Get the schedule reoccurrence  | 
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| 302 | *  | 
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| 303 | */  | 
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| 304 | 	public function get_reoccurrence() { | 
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| 307 | |||
| 308 | /**  | 
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| 309 | * Set the schedule reoccurrence  | 
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| 310 | *  | 
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| 311 | * @param string $reoccurrence  | 
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| 312 | *  | 
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| 313 | * @return \WP_Error|null|boolean  | 
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| 314 | */  | 
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| 315 | 	public function set_reoccurrence( $reoccurrence ) { | 
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| 342 | |||
| 343 | /**  | 
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| 344 | * Get the interval between backups  | 
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| 345 | *  | 
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| 346 | * @return int  | 
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| 347 | */  | 
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| 348 | 	public function get_interval() { | 
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| 359 | |||
| 360 | /**  | 
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| 361 | * Get the next occurrence of this scheduled backup  | 
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| 362 | *  | 
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| 363 | */  | 
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| 364 | 	public function get_next_occurrence( $gmt = true ) { | 
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| 379 | |||
| 380 | 	public function is_cron_scheduled() { | 
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| 383 | |||
| 384 | /**  | 
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| 385 | * Schedule the backup cron  | 
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| 386 | *  | 
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| 387 | */  | 
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| 388 | 	public function schedule() { | 
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| 398 | |||
| 399 | |||
| 400 | /**  | 
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| 401 | * Unschedule the backup cron.  | 
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| 402 | *  | 
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| 403 | * @return void  | 
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| 404 | */  | 
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| 405 | 	public function unschedule() { | 
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| 408 | |||
| 409 | /**  | 
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| 410 | * Run the backup  | 
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| 411 | *  | 
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| 412 | */  | 
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| 413 | 	public function run() { | 
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| 456 | |||
| 457 | 	public function get_backup_filename() { | 
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| 465 | |||
| 466 | 	public function get_database_dump_filename() { | 
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| 469 | |||
| 470 | /**  | 
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| 471 | * Hook into the actions fired in the Backup class and set the status  | 
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| 472 | *  | 
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| 473 | * @param $action  | 
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| 474 | */  | 
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| 475 | 	public function do_action( $action, Backup $backup ) { | 
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| 487 | |||
| 488 | /**  | 
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| 489 | * Calculate schedule run time.  | 
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| 490 | *  | 
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| 491 | * @param int Timestamp $end  | 
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| 492 | */  | 
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| 493 | 	public function update_average_schedule_run_time( $start, $end ) { | 
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| 516 | |||
| 517 | /**  | 
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| 518 | * Calculates the average run time for this schedule.  | 
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| 519 | *  | 
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| 520 | * @return string  | 
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| 521 | */  | 
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| 522 | 	public function get_schedule_average_duration() { | 
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| 560 | |||
| 561 | /**  | 
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| 562 | * Get the backups created by this schedule  | 
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| 563 | *  | 
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| 564 | * @todo look into using recursiveDirectoryIterator and recursiveRegexIterator  | 
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| 565 | * @return string[] - file paths of the backups  | 
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| 566 | */  | 
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| 567 | 	public function get_backups() { | 
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| 590 | |||
| 591 | /**  | 
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| 592 | * Delete old backups  | 
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| 593 | *  | 
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| 594 | * @access private  | 
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| 595 | */  | 
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| 596 | 	public function delete_old_backups() { | 
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| 605 | |||
| 606 | /**  | 
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| 607 | * Delete a specific back up file created by this schedule  | 
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| 608 | *  | 
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| 609 | * @param string $filepath  | 
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| 610 | *  | 
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| 611 | * @return \WP_Error|boolean  | 
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| 612 | */  | 
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| 613 | 	public function delete_backup( $filepath ) { | 
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| 635 | |||
| 636 | /**  | 
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| 637 | * Delete all back up files created by this schedule  | 
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| 638 | *  | 
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| 639 | */  | 
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| 640 | 	public function delete_backups() { | 
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| 643 | |||
| 644 | /**  | 
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| 645 | * Save the schedules options.  | 
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| 646 | *  | 
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| 647 | */  | 
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| 648 | 	public function save() { | 
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| 656 | |||
| 657 | /**  | 
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| 658 | * Cancel this schedule  | 
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| 659 | *  | 
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| 660 | * Cancels the cron job, removes the schedules options  | 
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| 661 | * and optionally deletes all backups created by  | 
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| 662 | * this schedule.  | 
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| 663 | *  | 
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| 664 | */  | 
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| 665 | 	public function cancel( $delete_backups = false ) { | 
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| 679 | |||
| 680 | }  | 
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| 681 | 
It seems like the type of the argument is not accepted by the function/method which you are calling.
In some cases, in particular if PHP’s automatic type-juggling kicks in this might be fine. In other cases, however this might be a bug.
We suggest to add an explicit type cast like in the following example: