PageProps.php

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<?php
class PageProps {

    private static $instance;

    public static function overrideInstance( PageProps $store = null ) {
        if ( !defined( 'MW_PHPUNIT_TEST' ) ) {
            throw new MWException(
                'Cannot override ' . __CLASS__ . 'default instance in operation.'
            );
        }
        $previousValue = self::$instance;
        self::$instance = $store;
        return new ScopedCallback( function() use ( $previousValue ) {
            self::$instance = $previousValue;
        } );
    }

    public static function getInstance() {
        if ( self::$instance === null ) {
            self::$instance = new self();
        }
        return self::$instance;
    }

    const CACHE_TTL = 10; // integer; TTL in seconds
    const CACHE_SIZE = 100; // integer; max cached pages

    private $cache = null;

    private function __construct() {
        $this->cache = new ProcessCacheLRU( self::CACHE_SIZE );
    }

    public function getProperties( $titles, $propertyNames ) {
        if ( is_array( $propertyNames ) ) {
            $gotArray = true;
        } else {
            $propertyNames = [ $propertyNames ];
            $gotArray = false;
        }

        $values = [];
        $goodIDs = $this->getGoodIDs( $titles );
        $queryIDs = [];
        foreach ( $goodIDs as $pageID ) {
            foreach ( $propertyNames as $propertyName ) {
                $propertyValue = $this->getCachedProperty( $pageID, $propertyName );
                if ( $propertyValue === false ) {
                    $queryIDs[] = $pageID;
                    break;
                } else {
                    if ( $gotArray ) {
                        $values[$pageID][$propertyName] = $propertyValue;
                    } else {
                        $values[$pageID] = $propertyValue;
                    }
                }
            }
        }

        if ( $queryIDs ) {
            $dbr = wfGetDB( DB_SLAVE );
            $result = $dbr->select(
                'page_props',
                [
                    'pp_page',
                    'pp_propname',
                    'pp_value'
                ],
                [
                    'pp_page' => $queryIDs,
                    'pp_propname' => $propertyNames
                ],
                __METHOD__
            );

            foreach ( $result as $row ) {
                $pageID = $row->pp_page;
                $propertyName = $row->pp_propname;
                $propertyValue = $row->pp_value;
                $this->cacheProperty( $pageID, $propertyName, $propertyValue );
                if ( $gotArray ) {
                    $values[$pageID][$propertyName] = $propertyValue;
                } else {
                    $values[$pageID] = $propertyValue;
                }
            }
        }

        return $values;
    }

    public function getAllProperties( $titles ) {
        $values = [];
        $goodIDs = $this->getGoodIDs( $titles );
        $queryIDs = [];
        foreach ( $goodIDs as $pageID ) {
            $pageProperties = $this->getCachedProperties( $pageID );
            if ( $pageProperties === false ) {
                $queryIDs[] = $pageID;
            } else {
                $values[$pageID] = $pageProperties;
            }
        }

        if ( $queryIDs != [] ) {
            $dbr = wfGetDB( DB_SLAVE );
            $result = $dbr->select(
                'page_props',
                [
                    'pp_page',
                    'pp_propname',
                    'pp_value'
                ],
                [
                    'pp_page' => $queryIDs,
                ],
                __METHOD__
            );

            $currentPageID = 0;
            $pageProperties = [];
            foreach ( $result as $row ) {
                $pageID = $row->pp_page;
                if ( $currentPageID != $pageID ) {
                    if ( $pageProperties != [] ) {
                        $this->cacheProperties( $currentPageID, $pageProperties );
                        $values[$currentPageID] = $pageProperties;
                    }
                    $currentPageID = $pageID;
                    $pageProperties = [];
                }
                $pageProperties[$row->pp_propname] = $row->pp_value;
            }
            if ( $pageProperties != [] ) {
                $this->cacheProperties( $pageID, $pageProperties );
                $values[$pageID] = $pageProperties;
            }
        }

        return $values;
    }

    private function getGoodIDs( $titles ) {
        $result = [];
        if ( is_array( $titles ) ) {
            foreach ( $titles as $title ) {
                $pageID = $title->getArticleID();
                if ( $pageID > 0 ) {
                    $result[] = $pageID;
                }
            }
        } else {
            $pageID = $titles->getArticleID();
            if ( $pageID > 0 ) {
                $result[] = $pageID;
            }
        }
        return $result;
    }

    private function getCachedProperty( $pageID, $propertyName ) {
        if ( $this->cache->has( $pageID, $propertyName, self::CACHE_TTL ) ) {
            return $this->cache->get( $pageID, $propertyName );
        }
        if ( $this->cache->has( 0, $pageID, self::CACHE_TTL ) ) {
            $pageProperties = $this->cache->get( 0, $pageID );
            if ( isset( $pageProperties[$propertyName] ) ) {
                return $pageProperties[$propertyName];
            }
        }
        return false;
    }

    private function getCachedProperties( $pageID ) {
        if ( $this->cache->has( 0, $pageID, self::CACHE_TTL ) ) {
            return $this->cache->get( 0, $pageID );
        }
        return false;
    }

    private function cacheProperty( $pageID, $propertyName, $propertyValue ) {
        $this->cache->set( $pageID, $propertyName, $propertyValue );
    }

    private function cacheProperties( $pageID, $pageProperties ) {
        $this->cache->clear( $pageID );
        $this->cache->set( 0, $pageID, $pageProperties );
    }
}