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:
1 | <?php |
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10 | class Backup_Status { |
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11 | |||
12 | /** |
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13 | * The filename for the backup file we are the tracking status of |
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14 | * |
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15 | * @var string |
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16 | */ |
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17 | private $filename = ''; |
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18 | |||
19 | /** |
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20 | * [$lock_handler description] |
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21 | * |
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22 | * @var LockHandler |
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23 | */ |
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24 | private $lock_handler = ''; |
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25 | |||
26 | private $callback; |
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27 | |||
28 | /** |
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29 | * @param string $id The unique id for the backup job |
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30 | */ |
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31 | public function __construct( $id ) { |
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35 | |||
36 | /** |
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37 | * Start the tracking a backup process. |
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38 | * |
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39 | * This creates a backup running file and issues a file lock. This prevents duplicate |
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40 | * instances of this backup process running concurrently and allows us to detect if |
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41 | * the PHP thread running the process is killed as that will clear the lock. |
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42 | * |
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43 | * @param string $backup_filename The filename for the backup file that we're tracking |
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44 | * @param string $status_message The initial status for the backup process |
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45 | * |
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46 | * @return boolean Whether the backup process was success marked as started |
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47 | */ |
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48 | public function start( $backup_filename, $status_message ) { |
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64 | |||
65 | /** |
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66 | * Mark a backup process as finished. |
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67 | * |
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68 | * This removes the file lock and deletes the running file. |
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69 | */ |
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70 | public function finish() { |
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83 | |||
84 | /** |
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85 | * Check if the backup has been started by checking if the running file |
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86 | * exists. |
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87 | * |
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88 | * @return boolean Whether the backup process has been started |
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89 | */ |
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90 | public function is_started() { |
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93 | |||
94 | public function is_running() { |
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109 | |||
110 | /** |
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111 | * If the running file exists but isn't locked then the thread that |
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112 | * the backup process is running in must have been killed. |
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113 | * |
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114 | * You should only be running this command from a separate thread |
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115 | * |
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116 | * @return boolean Whether the backup process has crashed or not |
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117 | */ |
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118 | public function has_crashed() { |
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121 | |||
122 | /** |
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123 | * Handle a process that's previouly crashed. |
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124 | * |
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125 | * Delete the partially created backup if it exists and then run the standard |
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126 | * cleanup tasks and set an error message for the user. |
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127 | * |
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128 | * @return bool Whether the crash was handled or not |
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129 | */ |
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130 | public function cleanup_after_crash() { |
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148 | |||
149 | /** |
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150 | * Catch fatal errors and react accordingly. |
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151 | * |
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152 | * Hooked into the shutdown action. If we've shutdown because of a Fatal error |
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153 | * then we cleanup and set an error message for the user. |
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154 | */ |
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155 | public function catch_fatals() { |
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177 | |||
178 | /** |
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179 | * Get the filepath for the backup file we're tracking |
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180 | * |
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181 | * @return string The path to the backup file |
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182 | */ |
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183 | public function get_backup_filename() { |
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195 | |||
196 | /** |
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197 | * Get the status of the running backup. |
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198 | * |
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199 | * @return string |
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200 | */ |
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201 | public function get_status() { |
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216 | |||
217 | /** |
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218 | * Set the status of the running backup |
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219 | * |
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220 | * @param string $message |
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221 | * |
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222 | * @return null |
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223 | */ |
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224 | public function set_status( $message ) { |
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244 | |||
245 | /** |
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246 | * Get the time that the current running backup was started |
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247 | * |
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248 | * @return int $timestamp |
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249 | */ |
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250 | public function get_start_time() { |
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265 | |||
266 | /** |
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267 | * Get the path to the backup running file that stores the running backup status |
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268 | * |
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269 | * @return string |
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270 | */ |
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271 | public function get_status_filepath() { |
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274 | |||
275 | public function set_status_callback( $callback ) { |
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278 | } |
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279 |
In PHP it is possible to write to properties without declaring them. For example, the following is perfectly valid PHP code:
Generally, it is a good practice to explictly declare properties to avoid accidental typos and provide IDE auto-completion: