e4bcbe722e
These are classes that provide facilities for use by any caller, are independent of user interface, and have a limited set of dependencies on the rest of MediaWiki. See the README file for a more precise definition. These classes cannot go in includes/libs because of a dependency on the MediaWiki framework, such as wfDebug() or MWException, but they are otherwise similar. I thought it would be useful to put them in their own directory, to make them more discoverable, and as part of a general program of reducing clutter in the base includes/ directory. I've probably missed a few classes which could be included here, but the following classes were considered and were rejected for now: * Fallback: single caller only * GitInfo: getViewers() has inappropriate dependencies * HttpFunctions: depends on configuration, $wgTitle * PoolCounter: depends on configuration * CacheHelper: depends on IContextSource, wfMemc() Also moved a couple of classes into libs/ instead, where that seemed to be more appropriate. Change-Id: I274cff805b7d694b728a89b764a049cd62d320fe
114 lines
3.3 KiB
PHP
114 lines
3.3 KiB
PHP
<?php
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/**
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* Convenience class for generating iterators from iterators.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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* http://www.gnu.org/copyleft/gpl.html
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*
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* @file
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* @author Aaron Schulz
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*/
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/**
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* Convenience class for generating iterators from iterators.
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*
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* @since 1.21
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*/
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class MappedIterator extends FilterIterator {
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/** @var callable */
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protected $vCallback;
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/** @var callable */
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protected $aCallback;
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/** @var array */
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protected $cache = array();
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protected $rewound = false; // boolean; whether rewind() has been called
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/**
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* Build an new iterator from a base iterator by having the former wrap the
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* later, returning the result of "value" callback for each current() invocation.
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* The callback takes the result of current() on the base iterator as an argument.
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* The keys of the base iterator are reused verbatim.
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*
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* An "accept" callback can also be provided which will be called for each value in
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* the base iterator (post-callback) and will return true if that value should be
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* included in iteration of the MappedIterator (otherwise it will be filtered out).
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*
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* @param Iterator|Array $iter
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* @param callable $vCallback Value transformation callback
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* @param array $options Options map (includes "accept") (since 1.22)
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* @throws MWException
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*/
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public function __construct( $iter, $vCallback, array $options = array() ) {
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if ( is_array( $iter ) ) {
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$baseIterator = new ArrayIterator( $iter );
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} elseif ( $iter instanceof Iterator ) {
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$baseIterator = $iter;
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} else {
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throw new MWException( "Invalid base iterator provided." );
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}
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parent::__construct( $baseIterator );
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$this->vCallback = $vCallback;
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$this->aCallback = isset( $options['accept'] ) ? $options['accept'] : null;
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}
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public function next() {
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$this->cache = array();
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parent::next();
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}
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public function rewind() {
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$this->rewound = true;
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$this->cache = array();
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parent::rewind();
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}
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public function accept() {
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$value = call_user_func( $this->vCallback, $this->getInnerIterator()->current() );
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$ok = ( $this->aCallback ) ? call_user_func( $this->aCallback, $value ) : true;
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if ( $ok ) {
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$this->cache['current'] = $value;
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}
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return $ok;
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}
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public function key() {
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$this->init();
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return parent::key();
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}
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public function valid() {
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$this->init();
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return parent::valid();
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}
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public function current() {
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$this->init();
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if ( parent::valid() ) {
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return $this->cache['current'];
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} else {
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return null; // out of range
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}
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}
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/**
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* Obviate the usual need for rewind() before using a FilterIterator in a manual loop
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*/
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protected function init() {
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if ( !$this->rewound ) {
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$this->rewind();
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}
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}
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}
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