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[mediawiki.git] / includes / db / ORMRow.php

<?php

/**
 * Abstract base class for representing objects that are stored in some DB table.
 * This is basically an ORM-like wrapper around rows in database tables that
 * aims to be both simple and very flexible. It is centered around an associative
 * array of fields and various methods to do common interaction with the database.
 *
 * These methods are likely candidates for overriding:
 * * getDefaults
 * * remove
 * * insert
 * * saveExisting
 * * loadSummaryFields
 * * getSummaryFields
 *
 * Main instance methods:
 * * getField(s)
 * * setField(s)
 * * save
 * * remove
 *
 * Main static methods:
 * * select
 * * update
 * * delete
 * * count
 * * has
 * * selectRow
 * * selectFields
 * * selectFieldsRow
 *
 * @since 1.20
 *
 * @file ORMRow.php
 *
 * @licence GNU GPL v2 or later
 * @author Jeroen De Dauw < jeroendedauw@gmail.com >
 */
abstract class ORMRow {

        /**
         * The fields of the object.
         * field name (w/o prefix) => value
         *
         * @since 1.20
         * @var array
         */
        protected $fields = array( 'id' => null );

        /**
         * @since 1.20
         * @var ORMTable
         */
        protected $table;

        /**
         * If the object should update summaries of linked items when changed.
         * For example, update the course_count field in universities when a course in courses is deleted.
         * Settings this to false can prevent needless updating work in situations
         * such as deleting a university, which will then delete all it's courses.
         *
         * @since 1.20
         * @var bool
         */
        protected $updateSummaries = true;

        /**
         * Indicates if the object is in summary mode.
         * This mode indicates that only summary fields got updated,
         * which allows for optimizations.
         *
         * @since 1.20
         * @var bool
         */
        protected $inSummaryMode = false;

        /**
         * Constructor.
         *
         * @since 1.20
         *
         * @param ORMTable $table
         * @param array|null $fields
         * @param boolean $loadDefaults
         */
        public function __construct( ORMTable $table, $fields = null, $loadDefaults = false ) {
                $this->table = $table;

                if ( !is_array( $fields ) ) {
                        $fields = array();
                }

                if ( $loadDefaults ) {
                        $fields = array_merge( $this->table->getDefaults(), $fields );
                }

                $this->setFields( $fields );
        }

        /**
         * Load the specified fields from the database.
         *
         * @since 1.20
         *
         * @param array|null $fields
         * @param boolean $override
         * @param boolean $skipLoaded
         *
         * @return bool Success indicator
         */
        public function loadFields( $fields = null, $override = true, $skipLoaded = false ) {
                if ( is_null( $this->getId() ) ) {
                        return false;
                }

                if ( is_null( $fields ) ) {
                        $fields = array_keys( $this->table->getFields() );
                }

                if ( $skipLoaded ) {
                        $fields = array_diff( $fields, array_keys( $this->fields ) );
                }

                if ( !empty( $fields ) ) {
                        $result = $this->table->rawSelectRow(
                                $this->table->getPrefixedFields( $fields ),
                                array( $this->table->getPrefixedField( 'id' ) => $this->getId() ),
                                array( 'LIMIT' => 1 )
                        );

                        if ( $result !== false ) {
                                $this->setFields( $this->table->getFieldsFromDBResult( $result ), $override );
                                return true;
                        }
                        return false;
                }

                return true;
        }

        /**
         * Gets the value of a field.
         *
         * @since 1.20
         *
         * @param string $name
         * @param mixed $default
         *
         * @throws MWException
         * @return mixed
         */
        public function getField( $name, $default = null ) {
                if ( $this->hasField( $name ) ) {
                        return $this->fields[$name];
                } elseif ( !is_null( $default ) ) {
                        return $default;
                } else {
                        throw new MWException( 'Attempted to get not-set field ' . $name );
                }
        }

        /**
         * Gets the value of a field but first loads it if not done so already.
         *
         * @since 1.20
         *
         * @param string$name
         *
         * @return mixed
         */
        public function loadAndGetField( $name ) {
                if ( !$this->hasField( $name ) ) {
                        $this->loadFields( array( $name ) );
                }

                return $this->getField( $name );
        }

        /**
         * Remove a field.
         *
         * @since 1.20
         *
         * @param string $name
         */
        public function removeField( $name ) {
                unset( $this->fields[$name] );
        }

        /**
         * Returns the objects database id.
         *
         * @since 1.20
         *
         * @return integer|null
         */
        public function getId() {
                return $this->getField( 'id' );
        }

        /**
         * Sets the objects database id.
         *
         * @since 1.20
         *
         * @param integer|null $id
         */
        public function setId( $id ) {
                $this->setField( 'id', $id );
        }

        /**
         * Gets if a certain field is set.
         *
         * @since 1.20
         *
         * @param string $name
         *
         * @return boolean
         */
        public function hasField( $name ) {
                return array_key_exists( $name, $this->fields );
        }

        /**
         * Gets if the id field is set.
         *
         * @since 1.20
         *
         * @return boolean
         */
        public function hasIdField() {
                return $this->hasField( 'id' )
                        && !is_null( $this->getField( 'id' ) );
        }

        /**
         * Sets multiple fields.
         *
         * @since 1.20
         *
         * @param array $fields The fields to set
         * @param boolean $override Override already set fields with the provided values?
         */
        public function setFields( array $fields, $override = true ) {
                foreach ( $fields as $name => $value ) {
                        if ( $override || !$this->hasField( $name ) ) {
                                $this->setField( $name, $value );
                        }
                }
        }

        /**
         * Gets the fields => values to write to the table.
         *
         * @since 1.20
         *
         * @return array
         */
        protected function getWriteValues() {
                $values = array();

                foreach ( $this->table->getFields() as $name => $type ) {
                        if ( array_key_exists( $name, $this->fields ) ) {
                                $value = $this->fields[$name];

                                switch ( $type ) {
                                        case 'array':
                                                $value = (array)$value;
                                        case 'blob':
                                                $value = serialize( $value );
                                }

                                $values[$this->table->getPrefixedField( $name )] = $value;
                        }
                }

                return $values;
        }

        /**
         * Serializes the object to an associative array which
         * can then easily be converted into JSON or similar.
         *
         * @since 1.20
         *
         * @param null|array $fields
         * @param boolean $incNullId
         *
         * @return array
         */
        public function toArray( $fields = null, $incNullId = false ) {
                $data = array();
                $setFields = array();

                if ( !is_array( $fields ) ) {
                        $setFields = $this->getSetFieldNames();
                } else {
                        foreach ( $fields as $field ) {
                                if ( $this->hasField( $field ) ) {
                                        $setFields[] = $field;
                                }
                        }
                }

                foreach ( $setFields as $field ) {
                        if ( $incNullId || $field != 'id' || $this->hasIdField() ) {
                                $data[$field] = $this->getField( $field );
                        }
                }

                return $data;
        }

        /**
         * Load the default values, via getDefaults.
         *
         *  @since 1.20
         *
         * @param boolean $override
         */
        public function loadDefaults( $override = true ) {
                $this->setFields( $this->table->getDefaults(), $override );
        }

        /**
         * Writes the answer to the database, either updating it
         * when it already exists, or inserting it when it doesn't.
         *
         * @since 1.20
         *
         * @param string|null $functionName
         *
         * @return boolean Success indicator
         */
        public function save( $functionName = null ) {
                if ( $this->hasIdField() ) {
                        return $this->saveExisting( $functionName );
                } else {
                        return $this->insert( $functionName );
                }
        }

        /**
         * Updates the object in the database.
         *
         * @since 1.20
         *
         * @param string|null $functionName
         *
         * @return boolean Success indicator
         */
        protected function saveExisting( $functionName = null ) {
                $dbw = wfGetDB( DB_MASTER );

                $success = $dbw->update(
                        $this->table->getName(),
                        $this->getWriteValues(),
                        $this->table->getPrefixedValues( $this->getUpdateConditions() ),
                        is_null( $functionName ) ? __METHOD__ : $functionName
                );

                return $success;
        }

        /**
         * Returns the WHERE considtions needed to identify this object so
         * it can be updated.
         *
         * @since 1.20
         *
         * @return array
         */
        protected function getUpdateConditions() {
                return array( 'id' => $this->getId() );
        }

        /**
         * Inserts the object into the database.
         *
         * @since 1.20
         *
         * @param string|null $functionName
         * @param array|null $options
         *
         * @return boolean Success indicator
         */
        protected function insert( $functionName = null, array $options = null ) {
                $dbw = wfGetDB( DB_MASTER );

                $result = $dbw->insert(
                        $this->table->getName(),
                        $this->getWriteValues(),
                        is_null( $functionName ) ? __METHOD__ : $functionName,
                        is_null( $options ) ? array( 'IGNORE' ) : $options
                );

                if ( $result ) {
                        $this->setField( 'id', $dbw->insertId() );
                }

                return $result;
        }

        /**
         * Removes the object from the database.
         *
         * @since 1.20
         *
         * @return boolean Success indicator
         */
        public function remove() {
                $this->beforeRemove();

                $success = $this->table->delete( array( 'id' => $this->getId() ) );

                if ( $success ) {
                        $this->onRemoved();
                }

                return $success;
        }

        /**
         * Gets called before an object is removed from the database.
         *
         * @since 1.20
         */
        protected function beforeRemove() {
                $this->loadFields( $this->getBeforeRemoveFields(), false, true );
        }

        /**
         * Before removal of an object happens, @see beforeRemove gets called.
         * This method loads the fields of which the names have been returned by this one (or all fields if null is returned).
         * This allows for loading info needed after removal to get rid of linked data and the like.
         *
         * @since 1.20
         *
         * @return array|null
         */
        protected function getBeforeRemoveFields() {
                return array();
        }

        /**
         * Gets called after successfull removal.
         * Can be overriden to get rid of linked data.
         *
         * @since 1.20
         */
        protected function onRemoved() {
                $this->setField( 'id', null );
        }

        /**
         * Return the names and values of the fields.
         *
         * @since 1.20
         *
         * @return array
         */
        public function getFields() {
                return $this->fields;
        }

        /**
         * Return the names of the fields.
         *
         * @since 1.20
         *
         * @return array
         */
        public function getSetFieldNames() {
                return array_keys( $this->fields );
        }

        /**
         * Sets the value of a field.
         * Strings can be provided for other types,
         * so this method can be called from unserialization handlers.
         *
         * @since 1.20
         *
         * @param string $name
         * @param mixed $value
         *
         * @throws MWException
         */
        public function setField( $name, $value ) {
                $fields = $this->table->getFields();

                if ( array_key_exists( $name, $fields ) ) {
                        switch ( $fields[$name] ) {
                                case 'int':
                                        $value = (int)$value;
                                        break;
                                case 'float':
                                        $value = (float)$value;
                                        break;
                                case 'bool':
                                        if ( is_string( $value ) ) {
                                                $value = $value !== '0';
                                        } elseif ( is_int( $value ) ) {
                                                $value = $value !== 0;
                                        }
                                        break;
                                case 'array':
                                        if ( is_string( $value ) ) {
                                                $value = unserialize( $value );
                                        }

                                        if ( !is_array( $value ) ) {
                                                $value = array();
                                        }
                                        break;
                                case 'blob':
                                        if ( is_string( $value ) ) {
                                                $value = unserialize( $value );
                                        }
                                        break;
                                case 'id':
                                        if ( is_string( $value ) ) {
                                                $value = (int)$value;
                                        }
                                        break;
                        }

                        $this->fields[$name] = $value;
                } else {
                        throw new MWException( 'Attempted to set unknown field ' . $name );
                }
        }

        /**
         * Add an amount (can be negative) to the specified field (needs to be numeric).
         *
         * @since 1.20
         *
         * @param string $field
         * @param integer $amount
         *
         * @return boolean Success indicator
         */
        public function addToField( $field, $amount ) {
                if ( $amount == 0 ) {
                        return true;
                }

                if ( !$this->hasIdField() ) {
                        return false;
                }

                $absoluteAmount = abs( $amount );
                $isNegative = $amount < 0;

                $dbw = wfGetDB( DB_MASTER );

                $fullField = $this->table->getPrefixedField( $field );

                $success = $dbw->update(
                        $this->table->getName(),
                        array( "$fullField=$fullField" . ( $isNegative ? '-' : '+' ) . $absoluteAmount ),
                        array( $this->table->getPrefixedField( 'id' ) => $this->getId() ),
                        __METHOD__
                );

                if ( $success && $this->hasField( $field ) ) {
                        $this->setField( $field, $this->getField( $field ) + $amount );
                }

                return $success;
        }

        /**
         * Return the names of the fields.
         *
         * @since 1.20
         *
         * @return array
         */
        public function getFieldNames() {
                return array_keys( $this->table->getFields() );
        }

        /**
         * Computes and updates the values of the summary fields.
         *
         * @since 1.20
         *
         * @param array|string|null $summaryFields
         */
        public function loadSummaryFields( $summaryFields = null ) {

        }

        /**
         * Sets the value for the @see $updateSummaries field.
         *
         * @since 1.20
         *
         * @param boolean $update
         */
        public function setUpdateSummaries( $update ) {
                $this->updateSummaries = $update;
        }

        /**
         * Sets the value for the @see $inSummaryMode field.
         *
         * @since 1.20
         *
         * @param boolean $summaryMode
         */
        public function setSummaryMode( $summaryMode ) {
                $this->inSummaryMode = $summaryMode;
        }

        /**
         * Return if any fields got changed.
         *
         * @since 1.20
         *
         * @param ORMRow $object
         * @param boolean|array $excludeSummaryFields
         *  When set to true, summary field changes are ignored.
         *  Can also be an array of fields to ignore.
         *
         * @return boolean
         */
        protected function fieldsChanged( ORMRow $object, $excludeSummaryFields = false ) {
                $exclusionFields = array();

                if ( $excludeSummaryFields !== false ) {
                        $exclusionFields = is_array( $excludeSummaryFields ) ? $excludeSummaryFields : $this->table->getSummaryFields();
                }

                foreach ( $this->fields as $name => $value ) {
                        $excluded = $excludeSummaryFields && in_array( $name, $exclusionFields );

                        if ( !$excluded && $object->getField( $name ) !== $value ) {
                                return true;
                        }
                }

                return false;
        }

        /**
         * Returns the table this ORMRow is a row in.
         *
         * @since 1.20
         *
         * @return ORMTable
         */
        public function getTable() {
                return $this->table;
        }

}