wikimedia /
mediawiki
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 SpecialWhatLinksHere 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 SpecialWhatLinksHere, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 29 | class SpecialWhatLinksHere extends IncludableSpecialPage { |
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| 30 | /** @var FormOptions */ |
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| 31 | protected $opts; |
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| 32 | |||
| 33 | protected $selfTitle; |
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| 34 | |||
| 35 | /** @var Title */ |
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| 36 | protected $target; |
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| 37 | |||
| 38 | protected $limits = [ 20, 50, 100, 250, 500 ]; |
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| 39 | |||
| 40 | public function __construct() { |
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| 43 | |||
| 44 | function execute( $par ) { |
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| 98 | |||
| 99 | /** |
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| 100 | * @param int $level Recursion level |
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| 101 | * @param Title $target Target title |
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| 102 | * @param int $limit Number of entries to display |
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| 103 | * @param int $from Display from this article ID (default: 0) |
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| 104 | * @param int $back Display from this article ID at backwards scrolling (default: 0) |
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| 105 | */ |
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| 106 | function showIndirectLinks( $level, $target, $limit, $from = 0, $back = 0 ) { |
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| 107 | $out = $this->getOutput(); |
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| 108 | $dbr = wfGetDB( DB_SLAVE ); |
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| 109 | |||
| 110 | $hidelinks = $this->opts->getValue( 'hidelinks' ); |
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| 111 | $hideredirs = $this->opts->getValue( 'hideredirs' ); |
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| 112 | $hidetrans = $this->opts->getValue( 'hidetrans' ); |
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| 113 | $hideimages = $target->getNamespace() != NS_FILE || $this->opts->getValue( 'hideimages' ); |
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| 114 | |||
| 115 | $fetchlinks = ( !$hidelinks || !$hideredirs ); |
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| 116 | |||
| 117 | // Build query conds in concert for all three tables... |
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| 118 | $conds['pagelinks'] = [ |
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| 119 | 'pl_namespace' => $target->getNamespace(), |
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| 120 | 'pl_title' => $target->getDBkey(), |
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| 121 | ]; |
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| 122 | $conds['templatelinks'] = [ |
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| 123 | 'tl_namespace' => $target->getNamespace(), |
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| 124 | 'tl_title' => $target->getDBkey(), |
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| 125 | ]; |
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| 126 | $conds['imagelinks'] = [ |
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| 127 | 'il_to' => $target->getDBkey(), |
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| 128 | ]; |
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| 129 | |||
| 130 | $namespace = $this->opts->getValue( 'namespace' ); |
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| 131 | $invert = $this->opts->getValue( 'invert' ); |
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| 132 | $nsComparison = ( $invert ? '!= ' : '= ' ) . $dbr->addQuotes( $namespace ); |
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| 133 | View Code Duplication | if ( is_int( $namespace ) ) { |
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| 134 | $conds['pagelinks'][] = "pl_from_namespace $nsComparison"; |
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| 135 | $conds['templatelinks'][] = "tl_from_namespace $nsComparison"; |
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| 136 | $conds['imagelinks'][] = "il_from_namespace $nsComparison"; |
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| 137 | } |
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| 138 | |||
| 139 | View Code Duplication | if ( $from ) { |
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| 140 | $conds['templatelinks'][] = "tl_from >= $from"; |
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| 141 | $conds['pagelinks'][] = "pl_from >= $from"; |
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| 142 | $conds['imagelinks'][] = "il_from >= $from"; |
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| 143 | } |
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| 144 | |||
| 145 | if ( $hideredirs ) { |
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| 146 | $conds['pagelinks']['rd_from'] = null; |
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| 147 | } elseif ( $hidelinks ) { |
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| 148 | $conds['pagelinks'][] = 'rd_from is NOT NULL'; |
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| 149 | } |
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| 150 | |||
| 151 | $queryFunc = function ( IDatabase $dbr, $table, $fromCol ) use ( |
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| 152 | $conds, $target, $limit |
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| 153 | ) { |
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| 154 | // Read an extra row as an at-end check |
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| 155 | $queryLimit = $limit + 1; |
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| 156 | $on = [ |
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| 157 | "rd_from = $fromCol", |
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| 158 | 'rd_title' => $target->getDBkey(), |
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| 159 | 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL' |
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| 160 | ]; |
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| 161 | $on['rd_namespace'] = $target->getNamespace(); |
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| 162 | // Inner LIMIT is 2X in case of stale backlinks with wrong namespaces |
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| 163 | $subQuery = $dbr->selectSQLText( |
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| 164 | [ $table, 'redirect', 'page' ], |
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| 165 | [ $fromCol, 'rd_from' ], |
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| 166 | $conds[$table], |
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| 167 | __CLASS__ . '::showIndirectLinks', |
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| 168 | // Force JOIN order per T106682 to avoid large filesorts |
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| 169 | [ 'ORDER BY' => $fromCol, 'LIMIT' => 2 * $queryLimit, 'STRAIGHT_JOIN' ], |
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| 170 | [ |
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| 171 | 'page' => [ 'INNER JOIN', "$fromCol = page_id" ], |
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| 172 | 'redirect' => [ 'LEFT JOIN', $on ] |
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| 173 | ] |
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| 174 | ); |
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| 175 | return $dbr->select( |
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| 176 | [ 'page', 'temp_backlink_range' => "($subQuery)" ], |
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| 177 | [ 'page_id', 'page_namespace', 'page_title', 'rd_from', 'page_is_redirect' ], |
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| 178 | [], |
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| 179 | __CLASS__ . '::showIndirectLinks', |
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| 180 | [ 'ORDER BY' => 'page_id', 'LIMIT' => $queryLimit ], |
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| 181 | [ 'page' => [ 'INNER JOIN', "$fromCol = page_id" ] ] |
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| 182 | ); |
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| 183 | }; |
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| 184 | |||
| 185 | if ( $fetchlinks ) { |
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| 186 | $plRes = $queryFunc( $dbr, 'pagelinks', 'pl_from' ); |
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| 187 | } |
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| 188 | |||
| 189 | if ( !$hidetrans ) { |
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| 190 | $tlRes = $queryFunc( $dbr, 'templatelinks', 'tl_from' ); |
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| 191 | } |
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| 192 | |||
| 193 | if ( !$hideimages ) { |
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| 194 | $ilRes = $queryFunc( $dbr, 'imagelinks', 'il_from' ); |
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| 195 | } |
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| 196 | |||
| 197 | if ( ( !$fetchlinks || !$plRes->numRows() ) |
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| 198 | && ( $hidetrans || !$tlRes->numRows() ) |
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| 199 | && ( $hideimages || !$ilRes->numRows() ) |
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| 200 | ) { |
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| 201 | if ( 0 == $level ) { |
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| 202 | if ( !$this->including() ) { |
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| 203 | $out->addHTML( $this->whatlinkshereForm() ); |
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| 204 | |||
| 205 | // Show filters only if there are links |
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| 206 | if ( $hidelinks || $hidetrans || $hideredirs || $hideimages ) { |
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| 207 | $out->addHTML( $this->getFilterPanel() ); |
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| 208 | } |
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| 209 | $errMsg = is_int( $namespace ) ? 'nolinkshere-ns' : 'nolinkshere'; |
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| 210 | $out->addWikiMsg( $errMsg, $this->target->getPrefixedText() ); |
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| 211 | $out->setStatusCode( 404 ); |
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| 212 | } |
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| 213 | } |
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| 214 | |||
| 215 | return; |
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| 216 | } |
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| 217 | |||
| 218 | // Read the rows into an array and remove duplicates |
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| 219 | // templatelinks comes second so that the templatelinks row overwrites the |
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| 220 | // pagelinks row, so we get (inclusion) rather than nothing |
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| 221 | if ( $fetchlinks ) { |
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| 222 | foreach ( $plRes as $row ) { |
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| 223 | $row->is_template = 0; |
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| 224 | $row->is_image = 0; |
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| 225 | $rows[$row->page_id] = $row; |
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| 226 | } |
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| 227 | } |
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| 228 | if ( !$hidetrans ) { |
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| 229 | foreach ( $tlRes as $row ) { |
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| 230 | $row->is_template = 1; |
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| 231 | $row->is_image = 0; |
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| 232 | $rows[$row->page_id] = $row; |
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| 233 | } |
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| 234 | } |
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| 235 | if ( !$hideimages ) { |
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| 236 | foreach ( $ilRes as $row ) { |
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| 237 | $row->is_template = 0; |
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| 238 | $row->is_image = 1; |
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| 239 | $rows[$row->page_id] = $row; |
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| 240 | } |
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| 241 | } |
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| 242 | |||
| 243 | // Sort by key and then change the keys to 0-based indices |
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| 244 | ksort( $rows ); |
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| 245 | $rows = array_values( $rows ); |
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| 246 | |||
| 247 | $numRows = count( $rows ); |
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| 248 | |||
| 249 | // Work out the start and end IDs, for prev/next links |
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| 250 | if ( $numRows > $limit ) { |
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| 251 | // More rows available after these ones |
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| 252 | // Get the ID from the last row in the result set |
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| 253 | $nextId = $rows[$limit]->page_id; |
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| 254 | // Remove undisplayed rows |
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| 255 | $rows = array_slice( $rows, 0, $limit ); |
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| 256 | } else { |
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| 257 | // No more rows after |
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| 258 | $nextId = false; |
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| 259 | } |
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| 260 | $prevId = $from; |
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| 261 | |||
| 262 | // use LinkBatch to make sure, that all required data (associated with Titles) |
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| 263 | // is loaded in one query |
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| 264 | $lb = new LinkBatch(); |
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| 265 | foreach ( $rows as $row ) { |
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| 266 | $lb->add( $row->page_namespace, $row->page_title ); |
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| 267 | } |
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| 268 | $lb->execute(); |
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| 269 | |||
| 270 | if ( $level == 0 ) { |
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| 271 | if ( !$this->including() ) { |
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| 272 | $out->addHTML( $this->whatlinkshereForm() ); |
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| 273 | $out->addHTML( $this->getFilterPanel() ); |
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| 274 | $out->addWikiMsg( 'linkshere', $this->target->getPrefixedText() ); |
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| 275 | |||
| 276 | $prevnext = $this->getPrevNext( $prevId, $nextId ); |
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| 277 | $out->addHTML( $prevnext ); |
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| 278 | } |
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| 279 | } |
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| 280 | $out->addHTML( $this->listStart( $level ) ); |
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| 281 | foreach ( $rows as $row ) { |
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| 282 | $nt = Title::makeTitle( $row->page_namespace, $row->page_title ); |
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| 283 | |||
| 284 | if ( $row->rd_from && $level < 2 ) { |
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| 285 | $out->addHTML( $this->listItem( $row, $nt, $target, true ) ); |
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| 286 | $this->showIndirectLinks( |
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| 287 | $level + 1, |
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| 288 | $nt, |
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| 289 | $this->getConfig()->get( 'MaxRedirectLinksRetrieved' ) |
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| 290 | ); |
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| 291 | $out->addHTML( Xml::closeElement( 'li' ) ); |
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| 292 | } else { |
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| 293 | $out->addHTML( $this->listItem( $row, $nt, $target ) ); |
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| 294 | } |
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| 295 | } |
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| 296 | |||
| 297 | $out->addHTML( $this->listEnd() ); |
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| 298 | |||
| 299 | if ( $level == 0 ) { |
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| 300 | if ( !$this->including() ) { |
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| 301 | $out->addHTML( $prevnext ); |
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| 302 | } |
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| 303 | } |
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| 304 | } |
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| 305 | |||
| 306 | protected function listStart( $level ) { |
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| 309 | |||
| 310 | protected function listItem( $row, $nt, $target, $notClose = false ) { |
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| 368 | |||
| 369 | protected function listEnd() { |
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| 372 | |||
| 373 | protected function wlhLink( Title $target, $text, $editText ) { |
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| 374 | static $title = null; |
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| 375 | if ( $title === null ) { |
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| 376 | $title = $this->getPageTitle(); |
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| 377 | } |
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| 378 | |||
| 379 | // always show a "<- Links" link |
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| 380 | $links = [ |
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| 381 | 'links' => Linker::linkKnown( |
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| 382 | $title, |
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| 383 | $text, |
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| 384 | [], |
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| 385 | [ 'target' => $target->getPrefixedText() ] |
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| 386 | ), |
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| 387 | ]; |
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| 388 | |||
| 389 | // if the page is editable, add an edit link |
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| 390 | View Code Duplication | if ( |
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| 391 | // check user permissions |
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| 392 | $this->getUser()->isAllowed( 'edit' ) && |
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| 393 | // check, if the content model is editable through action=edit |
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| 394 | ContentHandler::getForTitle( $target )->supportsDirectEditing() |
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| 395 | ) { |
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| 396 | $links['edit'] = Linker::linkKnown( |
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| 397 | $target, |
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| 398 | $editText, |
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| 399 | [], |
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| 400 | [ 'action' => 'edit' ] |
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| 401 | ); |
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| 402 | } |
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| 403 | |||
| 404 | // build the links html |
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| 405 | return $this->getLanguage()->pipeList( $links ); |
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| 406 | } |
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| 407 | |||
| 408 | function makeSelfLink( $text, $query ) { |
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| 416 | |||
| 417 | function getPrevNext( $prevId, $nextId ) { |
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| 446 | |||
| 447 | function whatlinkshereForm() { |
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| 506 | |||
| 507 | /** |
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| 508 | * Create filter panel |
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| 509 | * |
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| 510 | * @return string HTML fieldset and filter panel with the show/hide links |
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| 511 | */ |
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| 512 | function getFilterPanel() { |
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| 541 | |||
| 542 | /** |
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| 543 | * Return an array of subpages beginning with $search that this special page will accept. |
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| 544 | * |
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| 545 | * @param string $search Prefix to search for |
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| 546 | * @param int $limit Maximum number of results to return (usually 10) |
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| 547 | * @param int $offset Number of results to skip (usually 0) |
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| 548 | * @return string[] Matching subpages |
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| 549 | */ |
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| 550 | public function prefixSearchSubpages( $search, $limit, $offset ) { |
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| 553 | |||
| 554 | protected function getGroupName() { |
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| 557 | } |
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| 558 |
Loading history...
Adding an explicit array definition is generally preferable to implicit array definition as it guarantees a stable state of the code.
Let’s take a look at an example:
As you can see in this example, the array
$myArrayis initialized the first time when the foreach loop is entered. You can also see that the value of thebarkey is only written conditionally; thus, its value might result from a previous iteration.This might or might not be intended. To make your intention clear, your code more readible and to avoid accidental bugs, we recommend to add an explicit initialization $myArray = array() either outside or inside the foreach loop.