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<?php
/**
* OpenStack Swift based file backend.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
* http://www.gnu.org/copyleft/gpl.html
*
* @file
* @ingroup FileBackend
* @author Russ Nelson
*/
namespace Wikimedia\FileBackend\FileIteration;
use Iterator;
use Traversable;
use Wikimedia\FileBackend\SwiftFileBackend;
/**
* SwiftFileBackend helper class to page through listings.
* Swift also has a listing limit of 10,000 objects for performance.
* Do not use this class from places outside SwiftFileBackend.
*
* @ingroup FileBackend
*/
abstract class SwiftFileBackendList implements Iterator {
/** @var string[]|array[] Current page of entries; path list or (path,stat map) list */
protected $iterableBuffer = [];
/** @var string|null Continuation marker; the next page starts *after* this path */
protected $continueAfter = null;
/** @var int */
protected $pos = 0;
/** @var array */
protected $params = [];
/** @var SwiftFileBackend */
protected $backend;
/** @var string Container name */
protected $container;
/** @var string Storage directory */
protected $dir;
/** @var int */
protected $suffixStart;
private const PAGE_SIZE = 9000; // file listing buffer size
/**
* @param SwiftFileBackend $backend
* @param string $fullCont Resolved container name
* @param string $dir Resolved directory relative to container
* @param array $params
* @note This defers I/O by not buffering the first page (useful for AppendIterator use)
* @note Do not call current()/valid() without calling rewind() first
*/
public function __construct( SwiftFileBackend $backend, $fullCont, $dir, array $params ) {
$this->backend = $backend;
$this->container = $fullCont;
$this->dir = $dir;
if ( substr( $this->dir, -1 ) === '/' ) {
$this->dir = substr( $this->dir, 0, -1 ); // remove trailing slash
}
if ( $this->dir == '' ) { // whole container
$this->suffixStart = 0;
} else { // dir within container
$this->suffixStart = strlen( $this->dir ) + 1; // size of "path/to/dir/"
}
$this->params = $params;
}
/**
* @see Iterator::key()
* @return int
*/
public function key(): int {
return $this->pos;
}
/**
* @inheritDoc
*/
public function next(): void {
++$this->pos;
if ( $this->iterableBuffer === null ) {
// Last page of entries failed to load
return;
}
// Advance to the next entry in the page
next( $this->iterableBuffer );
// Check if there are no entries left in this page and
// advance to the next page if this page was not empty.
if ( !$this->valid() && count( $this->iterableBuffer ) ) {
$this->iterableBuffer = $this->pageFromList(
$this->container,
$this->dir,
$this->continueAfter,
self::PAGE_SIZE,
$this->params
);
}
}
/**
* @inheritDoc
*/
public function rewind(): void {
$this->pos = 0;
$this->continueAfter = null;
$this->iterableBuffer = $this->pageFromList(
$this->container,
$this->dir,
// @phan-suppress-next-line PhanTypeMismatchArgumentPropertyReferenceReal
$this->continueAfter,
self::PAGE_SIZE,
$this->params
);
}
/**
* @see Iterator::valid()
* @return bool
*/
public function valid(): bool {
if ( $this->iterableBuffer === null ) {
// Last page of entries failed to load
return false;
}
// Note that entries (paths/tuples) are never boolean
return ( current( $this->iterableBuffer ) !== false );
}
/**
* Get the next page of entries
*
* @param string $container Resolved container name
* @param string $dir Resolved path relative to container
* @param string &$after @phan-output-reference Continuation marker
* @param int $limit
* @param array $params
* @return Traversable|array
*/
abstract protected function pageFromList( $container, $dir, &$after, $limit, array $params );
}
/** @deprecated class alias since 1.43 */
class_alias( SwiftFileBackendList::class, 'SwiftFileBackendList' );
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