wiki.techinc.nl/includes/filerepo/backend/FileBackendStore.php
Aaron 159cc27fde [FileBackend] A few code cleanups and some error message improvements.
Change-Id: I75f066104b98638ca956042c4e877c0f6327509c
2012-05-17 11:34:15 -07:00

1689 lines
54 KiB
PHP

<?php
/**
* Base class for all backends using particular storage medium.
*
* 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 Aaron Schulz
*/
/**
* @brief Base class for all backends using particular storage medium.
*
* This class defines the methods as abstract that subclasses must implement.
* Outside callers should *not* use functions with "Internal" in the name.
*
* The FileBackend operations are implemented using basic functions
* such as storeInternal(), copyInternal(), deleteInternal() and the like.
* This class is also responsible for path resolution and sanitization.
*
* @ingroup FileBackend
* @since 1.19
*/
abstract class FileBackendStore extends FileBackend {
/** @var BagOStuff */
protected $memCache;
/** @var Array Map of paths to small (RAM/disk) cache items */
protected $cache = array(); // (storage path => key => value)
protected $maxCacheSize = 300; // integer; max paths with entries
/** @var Array Map of paths to large (RAM/disk) cache items */
protected $expensiveCache = array(); // (storage path => key => value)
protected $maxExpensiveCacheSize = 5; // integer; max paths with entries
/** @var Array Map of container names to sharding settings */
protected $shardViaHashLevels = array(); // (container name => config array)
protected $maxFileSize = 4294967296; // integer bytes (4GiB)
/**
* @see FileBackend::__construct()
*
* @param $config Array
*/
public function __construct( array $config ) {
parent::__construct( $config );
$this->memCache = new EmptyBagOStuff(); // disabled by default
}
/**
* Get the maximum allowable file size given backend
* medium restrictions and basic performance constraints.
* Do not call this function from places outside FileBackend and FileOp.
*
* @return integer Bytes
*/
final public function maxFileSizeInternal() {
return $this->maxFileSize;
}
/**
* Check if a file can be created at a given storage path.
* FS backends should check if the parent directory exists and the file is writable.
* Backends using key/value stores should check if the container exists.
*
* @param $storagePath string
* @return bool
*/
abstract public function isPathUsableInternal( $storagePath );
/**
* Create a file in the backend with the given contents.
* Do not call this function from places outside FileBackend and FileOp.
*
* $params include:
* content : the raw file contents
* dst : destination storage path
* overwrite : overwrite any file that exists at the destination
* async : Status will be returned immediately if supported.
* If the status is OK, then its value field will be
* set to a FileBackendStoreOpHandle object.
*
* @param $params Array
* @return Status
*/
final public function createInternal( array $params ) {
wfProfileIn( __METHOD__ );
wfProfileIn( __METHOD__ . '-' . $this->name );
if ( strlen( $params['content'] ) > $this->maxFileSizeInternal() ) {
$status = Status::newFatal( 'backend-fail-maxsize',
$params['dst'], $this->maxFileSizeInternal() );
} else {
$status = $this->doCreateInternal( $params );
$this->clearCache( array( $params['dst'] ) );
$this->deleteFileCache( $params['dst'] ); // persistent cache
}
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
return $status;
}
/**
* @see FileBackendStore::createInternal()
*/
abstract protected function doCreateInternal( array $params );
/**
* Store a file into the backend from a file on disk.
* Do not call this function from places outside FileBackend and FileOp.
*
* $params include:
* src : source path on disk
* dst : destination storage path
* overwrite : overwrite any file that exists at the destination
* async : Status will be returned immediately if supported.
* If the status is OK, then its value field will be
* set to a FileBackendStoreOpHandle object.
*
* @param $params Array
* @return Status
*/
final public function storeInternal( array $params ) {
wfProfileIn( __METHOD__ );
wfProfileIn( __METHOD__ . '-' . $this->name );
if ( filesize( $params['src'] ) > $this->maxFileSizeInternal() ) {
$status = Status::newFatal( 'backend-fail-maxsize',
$params['dst'], $this->maxFileSizeInternal() );
} else {
$status = $this->doStoreInternal( $params );
$this->clearCache( array( $params['dst'] ) );
$this->deleteFileCache( $params['dst'] ); // persistent cache
}
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
return $status;
}
/**
* @see FileBackendStore::storeInternal()
*/
abstract protected function doStoreInternal( array $params );
/**
* Copy a file from one storage path to another in the backend.
* Do not call this function from places outside FileBackend and FileOp.
*
* $params include:
* src : source storage path
* dst : destination storage path
* overwrite : overwrite any file that exists at the destination
* async : Status will be returned immediately if supported.
* If the status is OK, then its value field will be
* set to a FileBackendStoreOpHandle object.
*
* @param $params Array
* @return Status
*/
final public function copyInternal( array $params ) {
wfProfileIn( __METHOD__ );
wfProfileIn( __METHOD__ . '-' . $this->name );
$status = $this->doCopyInternal( $params );
$this->clearCache( array( $params['dst'] ) );
$this->deleteFileCache( $params['dst'] ); // persistent cache
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
return $status;
}
/**
* @see FileBackendStore::copyInternal()
*/
abstract protected function doCopyInternal( array $params );
/**
* Delete a file at the storage path.
* Do not call this function from places outside FileBackend and FileOp.
*
* $params include:
* src : source storage path
* ignoreMissingSource : do nothing if the source file does not exist
* async : Status will be returned immediately if supported.
* If the status is OK, then its value field will be
* set to a FileBackendStoreOpHandle object.
*
* @param $params Array
* @return Status
*/
final public function deleteInternal( array $params ) {
wfProfileIn( __METHOD__ );
wfProfileIn( __METHOD__ . '-' . $this->name );
$status = $this->doDeleteInternal( $params );
$this->clearCache( array( $params['src'] ) );
$this->deleteFileCache( $params['src'] ); // persistent cache
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
return $status;
}
/**
* @see FileBackendStore::deleteInternal()
*/
abstract protected function doDeleteInternal( array $params );
/**
* Move a file from one storage path to another in the backend.
* Do not call this function from places outside FileBackend and FileOp.
*
* $params include:
* src : source storage path
* dst : destination storage path
* overwrite : overwrite any file that exists at the destination
* async : Status will be returned immediately if supported.
* If the status is OK, then its value field will be
* set to a FileBackendStoreOpHandle object.
*
* @param $params Array
* @return Status
*/
final public function moveInternal( array $params ) {
wfProfileIn( __METHOD__ );
wfProfileIn( __METHOD__ . '-' . $this->name );
$status = $this->doMoveInternal( $params );
$this->clearCache( array( $params['src'], $params['dst'] ) );
$this->deleteFileCache( $params['src'] ); // persistent cache
$this->deleteFileCache( $params['dst'] ); // persistent cache
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
return $status;
}
/**
* @see FileBackendStore::moveInternal()
* @return Status
*/
protected function doMoveInternal( array $params ) {
unset( $params['async'] ); // two steps, won't work here :)
// Copy source to dest
$status = $this->copyInternal( $params );
if ( $status->isOK() ) {
// Delete source (only fails due to races or medium going down)
$status->merge( $this->deleteInternal( array( 'src' => $params['src'] ) ) );
$status->setResult( true, $status->value ); // ignore delete() errors
}
return $status;
}
/**
* No-op file operation that does nothing.
* Do not call this function from places outside FileBackend and FileOp.
*
* @param $params Array
* @return Status
*/
final public function nullInternal( array $params ) {
return Status::newGood();
}
/**
* @see FileBackend::concatenate()
* @return Status
*/
final public function concatenate( array $params ) {
wfProfileIn( __METHOD__ );
wfProfileIn( __METHOD__ . '-' . $this->name );
$status = Status::newGood();
// Try to lock the source files for the scope of this function
$scopeLockS = $this->getScopedFileLocks( $params['srcs'], LockManager::LOCK_UW, $status );
if ( $status->isOK() ) {
// Actually do the concatenation
$status->merge( $this->doConcatenate( $params ) );
}
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
return $status;
}
/**
* @see FileBackendStore::concatenate()
* @return Status
*/
protected function doConcatenate( array $params ) {
$status = Status::newGood();
$tmpPath = $params['dst']; // convenience
// Check that the specified temp file is valid...
wfSuppressWarnings();
$ok = ( is_file( $tmpPath ) && !filesize( $tmpPath ) );
wfRestoreWarnings();
if ( !$ok ) { // not present or not empty
$status->fatal( 'backend-fail-opentemp', $tmpPath );
return $status;
}
// Build up the temp file using the source chunks (in order)...
$tmpHandle = fopen( $tmpPath, 'ab' );
if ( $tmpHandle === false ) {
$status->fatal( 'backend-fail-opentemp', $tmpPath );
return $status;
}
foreach ( $params['srcs'] as $virtualSource ) {
// Get a local FS version of the chunk
$tmpFile = $this->getLocalReference( array( 'src' => $virtualSource ) );
if ( !$tmpFile ) {
$status->fatal( 'backend-fail-read', $virtualSource );
return $status;
}
// Get a handle to the local FS version
$sourceHandle = fopen( $tmpFile->getPath(), 'r' );
if ( $sourceHandle === false ) {
fclose( $tmpHandle );
$status->fatal( 'backend-fail-read', $virtualSource );
return $status;
}
// Append chunk to file (pass chunk size to avoid magic quotes)
if ( !stream_copy_to_stream( $sourceHandle, $tmpHandle ) ) {
fclose( $sourceHandle );
fclose( $tmpHandle );
$status->fatal( 'backend-fail-writetemp', $tmpPath );
return $status;
}
fclose( $sourceHandle );
}
if ( !fclose( $tmpHandle ) ) {
$status->fatal( 'backend-fail-closetemp', $tmpPath );
return $status;
}
clearstatcache(); // temp file changed
return $status;
}
/**
* @see FileBackend::doPrepare()
* @return Status
*/
final protected function doPrepare( array $params ) {
wfProfileIn( __METHOD__ );
wfProfileIn( __METHOD__ . '-' . $this->name );
$status = Status::newGood();
list( $fullCont, $dir, $shard ) = $this->resolveStoragePath( $params['dir'] );
if ( $dir === null ) {
$status->fatal( 'backend-fail-invalidpath', $params['dir'] );
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
return $status; // invalid storage path
}
if ( $shard !== null ) { // confined to a single container/shard
$status->merge( $this->doPrepareInternal( $fullCont, $dir, $params ) );
} else { // directory is on several shards
wfDebug( __METHOD__ . ": iterating over all container shards.\n" );
list( $b, $shortCont, $r ) = self::splitStoragePath( $params['dir'] );
foreach ( $this->getContainerSuffixes( $shortCont ) as $suffix ) {
$status->merge( $this->doPrepareInternal( "{$fullCont}{$suffix}", $dir, $params ) );
}
}
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
return $status;
}
/**
* @see FileBackendStore::doPrepare()
* @return Status
*/
protected function doPrepareInternal( $container, $dir, array $params ) {
return Status::newGood();
}
/**
* @see FileBackend::doSecure()
* @return Status
*/
final protected function doSecure( array $params ) {
wfProfileIn( __METHOD__ );
wfProfileIn( __METHOD__ . '-' . $this->name );
$status = Status::newGood();
list( $fullCont, $dir, $shard ) = $this->resolveStoragePath( $params['dir'] );
if ( $dir === null ) {
$status->fatal( 'backend-fail-invalidpath', $params['dir'] );
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
return $status; // invalid storage path
}
if ( $shard !== null ) { // confined to a single container/shard
$status->merge( $this->doSecureInternal( $fullCont, $dir, $params ) );
} else { // directory is on several shards
wfDebug( __METHOD__ . ": iterating over all container shards.\n" );
list( $b, $shortCont, $r ) = self::splitStoragePath( $params['dir'] );
foreach ( $this->getContainerSuffixes( $shortCont ) as $suffix ) {
$status->merge( $this->doSecureInternal( "{$fullCont}{$suffix}", $dir, $params ) );
}
}
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
return $status;
}
/**
* @see FileBackendStore::doSecure()
* @return Status
*/
protected function doSecureInternal( $container, $dir, array $params ) {
return Status::newGood();
}
/**
* @see FileBackend::doClean()
* @return Status
*/
final protected function doClean( array $params ) {
wfProfileIn( __METHOD__ );
wfProfileIn( __METHOD__ . '-' . $this->name );
$status = Status::newGood();
// Recursive: first delete all empty subdirs recursively
if ( !empty( $params['recursive'] ) && !$this->directoriesAreVirtual() ) {
$subDirsRel = $this->getTopDirectoryList( array( 'dir' => $params['dir'] ) );
if ( $subDirsRel !== null ) { // no errors
foreach ( $subDirsRel as $subDirRel ) {
$subDir = $params['dir'] . "/{$subDirRel}"; // full path
$status->merge( $this->doClean( array( 'dir' => $subDir ) + $params ) );
}
}
}
list( $fullCont, $dir, $shard ) = $this->resolveStoragePath( $params['dir'] );
if ( $dir === null ) {
$status->fatal( 'backend-fail-invalidpath', $params['dir'] );
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
return $status; // invalid storage path
}
// Attempt to lock this directory...
$filesLockEx = array( $params['dir'] );
$scopedLockE = $this->getScopedFileLocks( $filesLockEx, LockManager::LOCK_EX, $status );
if ( !$status->isOK() ) {
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
return $status; // abort
}
if ( $shard !== null ) { // confined to a single container/shard
$status->merge( $this->doCleanInternal( $fullCont, $dir, $params ) );
$this->deleteContainerCache( $fullCont ); // purge cache
} else { // directory is on several shards
wfDebug( __METHOD__ . ": iterating over all container shards.\n" );
list( $b, $shortCont, $r ) = self::splitStoragePath( $params['dir'] );
foreach ( $this->getContainerSuffixes( $shortCont ) as $suffix ) {
$status->merge( $this->doCleanInternal( "{$fullCont}{$suffix}", $dir, $params ) );
$this->deleteContainerCache( "{$fullCont}{$suffix}" ); // purge cache
}
}
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
return $status;
}
/**
* @see FileBackendStore::doClean()
* @return Status
*/
protected function doCleanInternal( $container, $dir, array $params ) {
return Status::newGood();
}
/**
* @see FileBackend::fileExists()
* @return bool|null
*/
final public function fileExists( array $params ) {
wfProfileIn( __METHOD__ );
wfProfileIn( __METHOD__ . '-' . $this->name );
$stat = $this->getFileStat( $params );
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
return ( $stat === null ) ? null : (bool)$stat; // null => failure
}
/**
* @see FileBackend::getFileTimestamp()
* @return bool
*/
final public function getFileTimestamp( array $params ) {
wfProfileIn( __METHOD__ );
wfProfileIn( __METHOD__ . '-' . $this->name );
$stat = $this->getFileStat( $params );
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
return $stat ? $stat['mtime'] : false;
}
/**
* @see FileBackend::getFileSize()
* @return bool
*/
final public function getFileSize( array $params ) {
wfProfileIn( __METHOD__ );
wfProfileIn( __METHOD__ . '-' . $this->name );
$stat = $this->getFileStat( $params );
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
return $stat ? $stat['size'] : false;
}
/**
* @see FileBackend::getFileStat()
* @return bool
*/
final public function getFileStat( array $params ) {
wfProfileIn( __METHOD__ );
wfProfileIn( __METHOD__ . '-' . $this->name );
$path = self::normalizeStoragePath( $params['src'] );
if ( $path === null ) {
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
return false; // invalid storage path
}
$latest = !empty( $params['latest'] ); // use latest data?
if ( !isset( $this->cache[$path]['stat'] ) ) {
$this->primeFileCache( array( $path ) ); // check persistent cache
}
if ( isset( $this->cache[$path]['stat'] ) ) {
// If we want the latest data, check that this cached
// value was in fact fetched with the latest available data.
if ( !$latest || $this->cache[$path]['stat']['latest'] ) {
$this->pingCache( $path ); // LRU
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
return $this->cache[$path]['stat'];
}
}
wfProfileIn( __METHOD__ . '-miss' );
wfProfileIn( __METHOD__ . '-miss-' . $this->name );
$stat = $this->doGetFileStat( $params );
wfProfileOut( __METHOD__ . '-miss-' . $this->name );
wfProfileOut( __METHOD__ . '-miss' );
if ( is_array( $stat ) ) { // don't cache negatives
$stat['latest'] = $latest;
$this->trimCache(); // limit memory
$this->cache[$path]['stat'] = $stat;
$this->setFileCache( $path, $stat ); // update persistent cache
}
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
return $stat;
}
/**
* @see FileBackendStore::getFileStat()
*/
abstract protected function doGetFileStat( array $params );
/**
* @see FileBackend::getFileContents()
* @return bool|string
*/
public function getFileContents( array $params ) {
wfProfileIn( __METHOD__ );
wfProfileIn( __METHOD__ . '-' . $this->name );
$tmpFile = $this->getLocalReference( $params );
if ( !$tmpFile ) {
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
return false;
}
wfSuppressWarnings();
$data = file_get_contents( $tmpFile->getPath() );
wfRestoreWarnings();
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
return $data;
}
/**
* @see FileBackend::getFileSha1Base36()
* @return bool|string
*/
final public function getFileSha1Base36( array $params ) {
wfProfileIn( __METHOD__ );
wfProfileIn( __METHOD__ . '-' . $this->name );
$path = $params['src'];
if ( isset( $this->cache[$path]['sha1'] ) ) {
$this->pingCache( $path ); // LRU
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
return $this->cache[$path]['sha1'];
}
wfProfileIn( __METHOD__ . '-miss' );
wfProfileIn( __METHOD__ . '-miss-' . $this->name );
$hash = $this->doGetFileSha1Base36( $params );
wfProfileOut( __METHOD__ . '-miss-' . $this->name );
wfProfileOut( __METHOD__ . '-miss' );
if ( $hash ) { // don't cache negatives
$this->trimCache(); // limit memory
$this->cache[$path]['sha1'] = $hash;
}
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
return $hash;
}
/**
* @see FileBackendStore::getFileSha1Base36()
* @return bool
*/
protected function doGetFileSha1Base36( array $params ) {
$fsFile = $this->getLocalReference( $params );
if ( !$fsFile ) {
return false;
} else {
return $fsFile->getSha1Base36();
}
}
/**
* @see FileBackend::getFileProps()
* @return Array
*/
final public function getFileProps( array $params ) {
wfProfileIn( __METHOD__ );
wfProfileIn( __METHOD__ . '-' . $this->name );
$fsFile = $this->getLocalReference( $params );
$props = $fsFile ? $fsFile->getProps() : FSFile::placeholderProps();
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
return $props;
}
/**
* @see FileBackend::getLocalReference()
* @return TempFSFile|null
*/
public function getLocalReference( array $params ) {
wfProfileIn( __METHOD__ );
wfProfileIn( __METHOD__ . '-' . $this->name );
$path = $params['src'];
if ( isset( $this->expensiveCache[$path]['localRef'] ) ) {
$this->pingExpensiveCache( $path );
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
return $this->expensiveCache[$path]['localRef'];
}
$tmpFile = $this->getLocalCopy( $params );
if ( $tmpFile ) { // don't cache negatives
$this->trimExpensiveCache(); // limit memory
$this->expensiveCache[$path]['localRef'] = $tmpFile;
}
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
return $tmpFile;
}
/**
* @see FileBackend::streamFile()
* @return Status
*/
final public function streamFile( array $params ) {
wfProfileIn( __METHOD__ );
wfProfileIn( __METHOD__ . '-' . $this->name );
$status = Status::newGood();
$info = $this->getFileStat( $params );
if ( !$info ) { // let StreamFile handle the 404
$status->fatal( 'backend-fail-notexists', $params['src'] );
}
// Set output buffer and HTTP headers for stream
$extraHeaders = isset( $params['headers'] ) ? $params['headers'] : array();
$res = StreamFile::prepareForStream( $params['src'], $info, $extraHeaders );
if ( $res == StreamFile::NOT_MODIFIED ) {
// do nothing; client cache is up to date
} elseif ( $res == StreamFile::READY_STREAM ) {
wfProfileIn( __METHOD__ . '-send' );
wfProfileIn( __METHOD__ . '-send-' . $this->name );
$status = $this->doStreamFile( $params );
wfProfileOut( __METHOD__ . '-send-' . $this->name );
wfProfileOut( __METHOD__ . '-send' );
} else {
$status->fatal( 'backend-fail-stream', $params['src'] );
}
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
return $status;
}
/**
* @see FileBackendStore::streamFile()
* @return Status
*/
protected function doStreamFile( array $params ) {
$status = Status::newGood();
$fsFile = $this->getLocalReference( $params );
if ( !$fsFile ) {
$status->fatal( 'backend-fail-stream', $params['src'] );
} elseif ( !readfile( $fsFile->getPath() ) ) {
$status->fatal( 'backend-fail-stream', $params['src'] );
}
return $status;
}
/**
* @see FileBackend::directoryExists()
* @return bool|null
*/
final public function directoryExists( array $params ) {
list( $fullCont, $dir, $shard ) = $this->resolveStoragePath( $params['dir'] );
if ( $dir === null ) {
return false; // invalid storage path
}
if ( $shard !== null ) { // confined to a single container/shard
return $this->doDirectoryExists( $fullCont, $dir, $params );
} else { // directory is on several shards
wfDebug( __METHOD__ . ": iterating over all container shards.\n" );
list( $b, $shortCont, $r ) = self::splitStoragePath( $params['dir'] );
$res = false; // response
foreach ( $this->getContainerSuffixes( $shortCont ) as $suffix ) {
$exists = $this->doDirectoryExists( "{$fullCont}{$suffix}", $dir, $params );
if ( $exists ) {
$res = true;
break; // found one!
} elseif ( $exists === null ) { // error?
$res = null; // if we don't find anything, it is indeterminate
}
}
return $res;
}
}
/**
* @see FileBackendStore::directoryExists()
*
* @param $container string Resolved container name
* @param $dir string Resolved path relative to container
* @param $params Array
* @return bool|null
*/
abstract protected function doDirectoryExists( $container, $dir, array $params );
/**
* @see FileBackend::getDirectoryList()
* @return Traversable|Array|null Returns null on failure
*/
final public function getDirectoryList( array $params ) {
list( $fullCont, $dir, $shard ) = $this->resolveStoragePath( $params['dir'] );
if ( $dir === null ) { // invalid storage path
return null;
}
if ( $shard !== null ) {
// File listing is confined to a single container/shard
return $this->getDirectoryListInternal( $fullCont, $dir, $params );
} else {
wfDebug( __METHOD__ . ": iterating over all container shards.\n" );
// File listing spans multiple containers/shards
list( $b, $shortCont, $r ) = self::splitStoragePath( $params['dir'] );
return new FileBackendStoreShardDirIterator( $this,
$fullCont, $dir, $this->getContainerSuffixes( $shortCont ), $params );
}
}
/**
* Do not call this function from places outside FileBackend
*
* @see FileBackendStore::getDirectoryList()
*
* @param $container string Resolved container name
* @param $dir string Resolved path relative to container
* @param $params Array
* @return Traversable|Array|null Returns null on failure
*/
abstract public function getDirectoryListInternal( $container, $dir, array $params );
/**
* @see FileBackend::getFileList()
* @return Traversable|Array|null Returns null on failure
*/
final public function getFileList( array $params ) {
list( $fullCont, $dir, $shard ) = $this->resolveStoragePath( $params['dir'] );
if ( $dir === null ) { // invalid storage path
return null;
}
if ( $shard !== null ) {
// File listing is confined to a single container/shard
return $this->getFileListInternal( $fullCont, $dir, $params );
} else {
wfDebug( __METHOD__ . ": iterating over all container shards.\n" );
// File listing spans multiple containers/shards
list( $b, $shortCont, $r ) = self::splitStoragePath( $params['dir'] );
return new FileBackendStoreShardFileIterator( $this,
$fullCont, $dir, $this->getContainerSuffixes( $shortCont ), $params );
}
}
/**
* Do not call this function from places outside FileBackend
*
* @see FileBackendStore::getFileList()
*
* @param $container string Resolved container name
* @param $dir string Resolved path relative to container
* @param $params Array
* @return Traversable|Array|null Returns null on failure
*/
abstract public function getFileListInternal( $container, $dir, array $params );
/**
* Return a list of FileOp objects from a list of operations.
* Do not call this function from places outside FileBackend.
*
* The result must have the same number of items as the input.
* An exception is thrown if an unsupported operation is requested.
*
* @param $ops Array Same format as doOperations()
* @return Array List of FileOp objects
* @throws MWException
*/
final public function getOperationsInternal( array $ops ) {
$supportedOps = array(
'store' => 'StoreFileOp',
'copy' => 'CopyFileOp',
'move' => 'MoveFileOp',
'delete' => 'DeleteFileOp',
'create' => 'CreateFileOp',
'null' => 'NullFileOp'
);
$performOps = array(); // array of FileOp objects
// Build up ordered array of FileOps...
foreach ( $ops as $operation ) {
$opName = $operation['op'];
if ( isset( $supportedOps[$opName] ) ) {
$class = $supportedOps[$opName];
// Get params for this operation
$params = $operation;
// Append the FileOp class
$performOps[] = new $class( $this, $params );
} else {
throw new MWException( "Operation '$opName' is not supported." );
}
}
return $performOps;
}
/**
* Get a list of storage paths to lock for a list of operations
* Returns an array with 'sh' (shared) and 'ex' (exclusive) keys,
* each corresponding to a list of storage paths to be locked.
*
* @param $performOps Array List of FileOp objects
* @return Array ('sh' => list of paths, 'ex' => list of paths)
*/
final public function getPathsToLockForOpsInternal( array $performOps ) {
// Build up a list of files to lock...
$paths = array( 'sh' => array(), 'ex' => array() );
foreach ( $performOps as $fileOp ) {
$paths['sh'] = array_merge( $paths['sh'], $fileOp->storagePathsRead() );
$paths['ex'] = array_merge( $paths['ex'], $fileOp->storagePathsChanged() );
}
// Optimization: if doing an EX lock anyway, don't also set an SH one
$paths['sh'] = array_diff( $paths['sh'], $paths['ex'] );
// Get a shared lock on the parent directory of each path changed
$paths['sh'] = array_merge( $paths['sh'], array_map( 'dirname', $paths['ex'] ) );
return $paths;
}
/**
* @see FileBackend::doOperationsInternal()
* @return Status
*/
protected function doOperationsInternal( array $ops, array $opts ) {
wfProfileIn( __METHOD__ );
wfProfileIn( __METHOD__ . '-' . $this->name );
$status = Status::newGood();
// Build up a list of FileOps...
$performOps = $this->getOperationsInternal( $ops );
// Acquire any locks as needed...
if ( empty( $opts['nonLocking'] ) ) {
// Build up a list of files to lock...
$paths = $this->getPathsToLockForOpsInternal( $performOps );
// Try to lock those files for the scope of this function...
$scopeLockS = $this->getScopedFileLocks( $paths['sh'], LockManager::LOCK_UW, $status );
$scopeLockE = $this->getScopedFileLocks( $paths['ex'], LockManager::LOCK_EX, $status );
if ( !$status->isOK() ) {
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
return $status; // abort
}
}
// Clear any file cache entries (after locks acquired)
$this->clearCache();
// Load from the persistent file and container caches
$this->primeFileCache( $performOps );
$this->primeContainerCache( $performOps );
// Actually attempt the operation batch...
$subStatus = FileOpBatch::attempt( $performOps, $opts, $this->fileJournal );
// Merge errors into status fields
$status->merge( $subStatus );
$status->success = $subStatus->success; // not done in merge()
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
return $status;
}
/**
* @see FileBackend::doQuickOperationsInternal()
* @return Status
* @throws MWException
*/
final protected function doQuickOperationsInternal( array $ops ) {
$status = Status::newGood();
$async = $this->parallelize;
$maxConcurrency = $this->concurrency; // throttle
$statuses = array(); // array of (index => Status)
$fileOpHandles = array(); // list of (index => handle) arrays
$curFileOpHandles = array(); // current handle batch
// Perform the sync-only ops and build up op handles for the async ops...
foreach ( $ops as $index => $params ) {
$method = $params['op'] . 'Internal'; // e.g. "storeInternal"
if ( !MWInit::methodExists( __CLASS__, $method ) ) {
throw new MWException( "Operation '{$params['op']}' is not supported." );
}
$subStatus = $this->$method( array( 'async' => $async ) + $params );
if ( $subStatus->value instanceof FileBackendStoreOpHandle ) { // async
if ( count( $curFileOpHandles ) >= $maxConcurrency ) {
$fileOpHandles[] = $curFileOpHandles; // push this batch
$curFileOpHandles = array();
}
$curFileOpHandles[$index] = $subStatus->value; // keep index
} else { // error or completed
$statuses[$index] = $subStatus; // keep index
}
}
if ( count( $curFileOpHandles ) ) {
$fileOpHandles[] = $curFileOpHandles; // last batch
}
// Do all the async ops that can be done concurrently...
foreach ( $fileOpHandles as $fileHandleBatch ) {
$statuses = $statuses + $this->executeOpHandlesInternal( $fileHandleBatch );
}
// Marshall and merge all the responses...
foreach ( $statuses as $index => $subStatus ) {
$status->merge( $subStatus );
if ( $subStatus->isOK() ) {
$status->success[$index] = true;
++$status->successCount;
} else {
$status->success[$index] = false;
++$status->failCount;
}
}
return $status;
}
/**
* Execute a list of FileBackendStoreOpHandle handles in parallel.
* The resulting Status object fields will correspond
* to the order in which the handles where given.
*
* @param $handles Array List of FileBackendStoreOpHandle objects
* @return Array Map of Status objects
* @throws MWException
*/
final public function executeOpHandlesInternal( array $fileOpHandles ) {
wfProfileIn( __METHOD__ );
wfProfileIn( __METHOD__ . '-' . $this->name );
foreach ( $fileOpHandles as $fileOpHandle ) {
if ( !( $fileOpHandle instanceof FileBackendStoreOpHandle ) ) {
throw new MWException( "Given a non-FileBackendStoreOpHandle object." );
} elseif ( $fileOpHandle->backend->getName() !== $this->getName() ) {
throw new MWException( "Given a FileBackendStoreOpHandle for the wrong backend." );
}
}
$res = $this->doExecuteOpHandlesInternal( $fileOpHandles );
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
return $res;
}
/**
* @see FileBackendStore::executeOpHandlesInternal()
* @return Array List of corresponding Status objects
* @throws MWException
*/
protected function doExecuteOpHandlesInternal( array $fileOpHandles ) {
foreach ( $fileOpHandles as $fileOpHandle ) { // OK if empty
throw new MWException( "This backend supports no asynchronous operations." );
}
return array();
}
/**
* @see FileBackend::clearCache()
*/
final public function clearCache( array $paths = null ) {
if ( is_array( $paths ) ) {
$paths = array_map( 'FileBackend::normalizeStoragePath', $paths );
$paths = array_filter( $paths, 'strlen' ); // remove nulls
}
if ( $paths === null ) {
$this->cache = array();
$this->expensiveCache = array();
} else {
foreach ( $paths as $path ) {
unset( $this->cache[$path] );
unset( $this->expensiveCache[$path] );
}
}
$this->doClearCache( $paths );
}
/**
* Clears any additional stat caches for storage paths
*
* @see FileBackend::clearCache()
*
* @param $paths Array Storage paths (optional)
* @return void
*/
protected function doClearCache( array $paths = null ) {}
/**
* Is this a key/value store where directories are just virtual?
* Virtual directories exists in so much as files exists that are
* prefixed with the directory path followed by a forward slash.
*
* @return bool
*/
abstract protected function directoriesAreVirtual();
/**
* Move a cache entry to the top (such as when accessed)
*
* @param $path string Storage path
* @return void
*/
protected function pingCache( $path ) {
if ( isset( $this->cache[$path] ) ) {
$tmp = $this->cache[$path];
unset( $this->cache[$path] );
$this->cache[$path] = $tmp;
}
}
/**
* Prune the inexpensive cache if it is too big to add an item
*
* @return void
*/
protected function trimCache() {
if ( count( $this->cache ) >= $this->maxCacheSize ) {
reset( $this->cache );
unset( $this->cache[key( $this->cache )] );
}
}
/**
* Move a cache entry to the top (such as when accessed)
*
* @param $path string Storage path
* @return void
*/
protected function pingExpensiveCache( $path ) {
if ( isset( $this->expensiveCache[$path] ) ) {
$tmp = $this->expensiveCache[$path];
unset( $this->expensiveCache[$path] );
$this->expensiveCache[$path] = $tmp;
}
}
/**
* Prune the expensive cache if it is too big to add an item
*
* @return void
*/
protected function trimExpensiveCache() {
if ( count( $this->expensiveCache ) >= $this->maxExpensiveCacheSize ) {
reset( $this->expensiveCache );
unset( $this->expensiveCache[key( $this->expensiveCache )] );
}
}
/**
* Check if a container name is valid.
* This checks for for length and illegal characters.
*
* @param $container string
* @return bool
*/
final protected static function isValidContainerName( $container ) {
// This accounts for Swift and S3 restrictions while leaving room
// for things like '.xxx' (hex shard chars) or '.seg' (segments).
// This disallows directory separators or traversal characters.
// Note that matching strings URL encode to the same string;
// in Swift, the length restriction is *after* URL encoding.
return preg_match( '/^[a-z0-9][a-z0-9-_]{0,199}$/i', $container );
}
/**
* Splits a storage path into an internal container name,
* an internal relative file name, and a container shard suffix.
* Any shard suffix is already appended to the internal container name.
* This also checks that the storage path is valid and within this backend.
*
* If the container is sharded but a suffix could not be determined,
* this means that the path can only refer to a directory and can only
* be scanned by looking in all the container shards.
*
* @param $storagePath string
* @return Array (container, path, container suffix) or (null, null, null) if invalid
*/
final protected function resolveStoragePath( $storagePath ) {
list( $backend, $container, $relPath ) = self::splitStoragePath( $storagePath );
if ( $backend === $this->name ) { // must be for this backend
$relPath = self::normalizeContainerPath( $relPath );
if ( $relPath !== null ) {
// Get shard for the normalized path if this container is sharded
$cShard = $this->getContainerShard( $container, $relPath );
// Validate and sanitize the relative path (backend-specific)
$relPath = $this->resolveContainerPath( $container, $relPath );
if ( $relPath !== null ) {
// Prepend any wiki ID prefix to the container name
$container = $this->fullContainerName( $container );
if ( self::isValidContainerName( $container ) ) {
// Validate and sanitize the container name (backend-specific)
$container = $this->resolveContainerName( "{$container}{$cShard}" );
if ( $container !== null ) {
return array( $container, $relPath, $cShard );
}
}
}
}
}
return array( null, null, null );
}
/**
* Like resolveStoragePath() except null values are returned if
* the container is sharded and the shard could not be determined.
*
* @see FileBackendStore::resolveStoragePath()
*
* @param $storagePath string
* @return Array (container, path) or (null, null) if invalid
*/
final protected function resolveStoragePathReal( $storagePath ) {
list( $container, $relPath, $cShard ) = $this->resolveStoragePath( $storagePath );
if ( $cShard !== null ) {
return array( $container, $relPath );
}
return array( null, null );
}
/**
* Get the container name shard suffix for a given path.
* Any empty suffix means the container is not sharded.
*
* @param $container string Container name
* @param $relStoragePath string Storage path relative to the container
* @return string|null Returns null if shard could not be determined
*/
final protected function getContainerShard( $container, $relPath ) {
list( $levels, $base, $repeat ) = $this->getContainerHashLevels( $container );
if ( $levels == 1 || $levels == 2 ) {
// Hash characters are either base 16 or 36
$char = ( $base == 36 ) ? '[0-9a-z]' : '[0-9a-f]';
// Get a regex that represents the shard portion of paths.
// The concatenation of the captures gives us the shard.
if ( $levels === 1 ) { // 16 or 36 shards per container
$hashDirRegex = '(' . $char . ')';
} else { // 256 or 1296 shards per container
if ( $repeat ) { // verbose hash dir format (e.g. "a/ab/abc")
$hashDirRegex = $char . '/(' . $char . '{2})';
} else { // short hash dir format (e.g. "a/b/c")
$hashDirRegex = '(' . $char . ')/(' . $char . ')';
}
}
// Allow certain directories to be above the hash dirs so as
// to work with FileRepo (e.g. "archive/a/ab" or "temp/a/ab").
// They must be 2+ chars to avoid any hash directory ambiguity.
$m = array();
if ( preg_match( "!^(?:[^/]{2,}/)*$hashDirRegex(?:/|$)!", $relPath, $m ) ) {
return '.' . implode( '', array_slice( $m, 1 ) );
}
return null; // failed to match
}
return ''; // no sharding
}
/**
* Check if a storage path maps to a single shard.
* Container dirs like "a", where the container shards on "x/xy",
* can reside on several shards. Such paths are tricky to handle.
*
* @param $storagePath string Storage path
* @return bool
*/
final public function isSingleShardPathInternal( $storagePath ) {
list( $c, $r, $shard ) = $this->resolveStoragePath( $storagePath );
return ( $shard !== null );
}
/**
* Get the sharding config for a container.
* If greater than 0, then all file storage paths within
* the container are required to be hashed accordingly.
*
* @param $container string
* @return Array (integer levels, integer base, repeat flag) or (0, 0, false)
*/
final protected function getContainerHashLevels( $container ) {
if ( isset( $this->shardViaHashLevels[$container] ) ) {
$config = $this->shardViaHashLevels[$container];
$hashLevels = (int)$config['levels'];
if ( $hashLevels == 1 || $hashLevels == 2 ) {
$hashBase = (int)$config['base'];
if ( $hashBase == 16 || $hashBase == 36 ) {
return array( $hashLevels, $hashBase, $config['repeat'] );
}
}
}
return array( 0, 0, false ); // no sharding
}
/**
* Get a list of full container shard suffixes for a container
*
* @param $container string
* @return Array
*/
final protected function getContainerSuffixes( $container ) {
$shards = array();
list( $digits, $base ) = $this->getContainerHashLevels( $container );
if ( $digits > 0 ) {
$numShards = pow( $base, $digits );
for ( $index = 0; $index < $numShards; $index++ ) {
$shards[] = '.' . wfBaseConvert( $index, 10, $base, $digits );
}
}
return $shards;
}
/**
* Get the full container name, including the wiki ID prefix
*
* @param $container string
* @return string
*/
final protected function fullContainerName( $container ) {
if ( $this->wikiId != '' ) {
return "{$this->wikiId}-$container";
} else {
return $container;
}
}
/**
* Resolve a container name, checking if it's allowed by the backend.
* This is intended for internal use, such as encoding illegal chars.
* Subclasses can override this to be more restrictive.
*
* @param $container string
* @return string|null
*/
protected function resolveContainerName( $container ) {
return $container;
}
/**
* Resolve a relative storage path, checking if it's allowed by the backend.
* This is intended for internal use, such as encoding illegal chars or perhaps
* getting absolute paths (e.g. FS based backends). Note that the relative path
* may be the empty string (e.g. the path is simply to the container).
*
* @param $container string Container name
* @param $relStoragePath string Storage path relative to the container
* @return string|null Path or null if not valid
*/
protected function resolveContainerPath( $container, $relStoragePath ) {
return $relStoragePath;
}
/**
* Get the cache key for a container
*
* @param $container string Resolved container name
* @return string
*/
private function containerCacheKey( $container ) {
return wfMemcKey( 'backend', $this->getName(), 'container', $container );
}
/**
* Set the cached info for a container
*
* @param $container string Resolved container name
* @param $val mixed Information to cache
* @return void
*/
final protected function setContainerCache( $container, $val ) {
$this->memCache->set( $this->containerCacheKey( $container ), $val, 14*86400 );
}
/**
* Delete the cached info for a container
*
* @param $containers string Resolved container name
* @return void
*/
final protected function deleteContainerCache( $container ) {
if ( !$this->memCache->delete( $this->containerCacheKey( $container ) ) ) {
trigger_error( "Unable to delete stat cache for container $container." );
}
}
/**
* Do a batch lookup from cache for container stats for all containers
* used in a list of container names, storage paths, or FileOp objects.
*
* @param $items Array
* @return void
*/
final protected function primeContainerCache( array $items ) {
wfProfileIn( __METHOD__ );
wfProfileIn( __METHOD__ . '-' . $this->name );
$paths = array(); // list of storage paths
$contNames = array(); // (cache key => resolved container name)
// Get all the paths/containers from the items...
foreach ( $items as $item ) {
if ( $item instanceof FileOp ) {
$paths = array_merge( $paths, $item->storagePathsRead() );
$paths = array_merge( $paths, $item->storagePathsChanged() );
} elseif ( self::isStoragePath( $item ) ) {
$paths[] = $item;
} elseif ( is_string( $item ) ) { // full container name
$contNames[$this->containerCacheKey( $item )] = $item;
}
}
// Get all the corresponding cache keys for paths...
foreach ( $paths as $path ) {
list( $fullCont, $r, $s ) = $this->resolveStoragePath( $path );
if ( $fullCont !== null ) { // valid path for this backend
$contNames[$this->containerCacheKey( $fullCont )] = $fullCont;
}
}
$contInfo = array(); // (resolved container name => cache value)
// Get all cache entries for these container cache keys...
$values = $this->memCache->getMulti( array_keys( $contNames ) );
foreach ( $values as $cacheKey => $val ) {
$contInfo[$contNames[$cacheKey]] = $val;
}
// Populate the container process cache for the backend...
$this->doPrimeContainerCache( array_filter( $contInfo, 'is_array' ) );
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
}
/**
* Fill the backend-specific process cache given an array of
* resolved container names and their corresponding cached info.
* Only containers that actually exist should appear in the map.
*
* @param $containerInfo Array Map of resolved container names to cached info
* @return void
*/
protected function doPrimeContainerCache( array $containerInfo ) {}
/**
* Get the cache key for a file path
*
* @param $path string Storage path
* @return string
*/
private function fileCacheKey( $path ) {
return wfMemcKey( 'backend', $this->getName(), 'file', sha1( $path ) );
}
/**
* Set the cached stat info for a file path
*
* @param $path string Storage path
* @param $val mixed Information to cache
* @return void
*/
final protected function setFileCache( $path, $val ) {
$this->memCache->set( $this->fileCacheKey( $path ), $val, 7*86400 );
}
/**
* Delete the cached stat info for a file path
*
* @param $path string Storage path
* @return void
*/
final protected function deleteFileCache( $path ) {
if ( !$this->memCache->delete( $this->fileCacheKey( $path ) ) ) {
trigger_error( "Unable to delete stat cache for file $path." );
}
}
/**
* Do a batch lookup from cache for file stats for all paths
* used in a list of storage paths or FileOp objects.
*
* @param $items Array List of storage paths or FileOps
* @return void
*/
final protected function primeFileCache( array $items ) {
wfProfileIn( __METHOD__ );
wfProfileIn( __METHOD__ . '-' . $this->name );
$paths = array(); // list of storage paths
$pathNames = array(); // (cache key => storage path)
// Get all the paths/containers from the items...
foreach ( $items as $item ) {
if ( $item instanceof FileOp ) {
$paths = array_merge( $paths, $item->storagePathsRead() );
$paths = array_merge( $paths, $item->storagePathsChanged() );
} elseif ( self::isStoragePath( $item ) ) {
$paths[] = $item;
}
}
// Get all the corresponding cache keys for paths...
foreach ( $paths as $path ) {
list( $cont, $rel, $s ) = $this->resolveStoragePath( $path );
if ( $rel !== null ) { // valid path for this backend
$pathNames[$this->fileCacheKey( $path )] = $path;
}
}
// Get all cache entries for these container cache keys...
$values = $this->memCache->getMulti( array_keys( $pathNames ) );
foreach ( $values as $cacheKey => $val ) {
if ( is_array( $val ) ) {
$this->trimCache(); // limit memory
$this->cache[$pathNames[$cacheKey]]['stat'] = $val;
}
}
wfProfileOut( __METHOD__ . '-' . $this->name );
wfProfileOut( __METHOD__ );
}
}
/**
* FileBackendStore helper class for performing asynchronous file operations.
*
* For example, calling FileBackendStore::createInternal() with the "async"
* param flag may result in a Status that contains this object as a value.
* This class is largely backend-specific and is mostly just "magic" to be
* passed to FileBackendStore::executeOpHandlesInternal().
*/
abstract class FileBackendStoreOpHandle {
/** @var Array */
public $params = array(); // params to caller functions
/** @var FileBackendStore */
public $backend;
/** @var Array */
public $resourcesToClose = array();
public $call; // string; name that identifies the function called
/**
* Close all open file handles
*
* @return void
*/
public function closeResources() {
array_map( 'fclose', $this->resourcesToClose );
}
}
/**
* FileBackendStore helper function to handle listings that span container shards.
* Do not use this class from places outside of FileBackendStore.
*
* @ingroup FileBackend
*/
abstract class FileBackendStoreShardListIterator implements Iterator {
/** @var FileBackendStore */
protected $backend;
/** @var Array */
protected $params;
/** @var Array */
protected $shardSuffixes;
protected $container; // string; full container name
protected $directory; // string; resolved relative path
/** @var Traversable */
protected $iter;
protected $curShard = 0; // integer
protected $pos = 0; // integer
/** @var Array */
protected $multiShardPaths = array(); // (rel path => 1)
/**
* @param $backend FileBackendStore
* @param $container string Full storage container name
* @param $dir string Storage directory relative to container
* @param $suffixes Array List of container shard suffixes
* @param $params Array
*/
public function __construct(
FileBackendStore $backend, $container, $dir, array $suffixes, array $params
) {
$this->backend = $backend;
$this->container = $container;
$this->directory = $dir;
$this->shardSuffixes = $suffixes;
$this->params = $params;
}
/**
* @see Iterator::current()
* @return string|bool String or false
*/
public function current() {
if ( is_array( $this->iter ) ) {
return current( $this->iter );
} else {
return $this->iter->current();
}
}
/**
* @see Iterator::key()
* @return integer
*/
public function key() {
return $this->pos;
}
/**
* @see Iterator::next()
* @return void
*/
public function next() {
++$this->pos;
if ( is_array( $this->iter ) ) {
next( $this->iter );
} else {
$this->iter->next();
}
// Filter out items that we already listed
$this->filterViaNext();
// Find the next non-empty shard if no elements are left
$this->nextShardIteratorIfNotValid();
}
/**
* @see Iterator::rewind()
* @return void
*/
public function rewind() {
$this->pos = 0;
$this->curShard = 0;
$this->setIteratorFromCurrentShard();
// Filter out items that we already listed
$this->filterViaNext();
// Find the next non-empty shard if this one has no elements
$this->nextShardIteratorIfNotValid();
}
/**
* @see Iterator::valid()
* @return bool
*/
public function valid() {
if ( $this->iter === null ) {
return false; // some failure?
} elseif ( is_array( $this->iter ) ) {
return ( current( $this->iter ) !== false ); // no paths can have this value
} else {
return $this->iter->valid();
}
}
/**
* Filter out duplicate items by advancing to the next ones
*/
protected function filterViaNext() {
while ( $this->iter->valid() ) {
$rel = $this->iter->current(); // path relative to given directory
$path = $this->params['dir'] . "/{$rel}"; // full storage path
if ( !$this->backend->isSingleShardPathInternal( $path ) ) {
// Don't keep listing paths that are on multiple shards
if ( isset( $this->multiShardPaths[$rel] ) ) {
$this->iter->next(); // we already listed this path
} else {
$this->multiShardPaths[$rel] = 1;
break;
}
}
}
}
/**
* If the list iterator for this container shard is out of items,
* then move on to the next container that has items.
* If there are none, then it advances to the last container.
*/
protected function nextShardIteratorIfNotValid() {
while ( !$this->valid() ) {
if ( ++$this->curShard >= count( $this->shardSuffixes ) ) {
break; // no more container shards
}
$this->setIteratorFromCurrentShard();
}
}
/**
* Set the list iterator to that of the current container shard
*/
protected function setIteratorFromCurrentShard() {
$suffix = $this->shardSuffixes[$this->curShard];
$this->iter = $this->listFromShard(
"{$this->container}{$suffix}", $this->directory, $this->params );
}
/**
* Get the list for a given container shard
*
* @param $container string Resolved container name
* @param $dir string Resolved path relative to container
* @param $params Array
* @return Traversable|Array|null
*/
abstract protected function listFromShard( $container, $dir, array $params );
}
/**
* Iterator for listing directories
*/
class FileBackendStoreShardDirIterator extends FileBackendStoreShardListIterator {
protected function listFromShard( $container, $dir, array $params ) {
return $this->backend->getDirectoryListInternal( $container, $dir, $params );
}
}
/**
* Iterator for listing regular files
*/
class FileBackendStoreShardFileIterator extends FileBackendStoreShardListIterator {
protected function listFromShard( $container, $dir, array $params ) {
return $this->backend->getFileListInternal( $container, $dir, $params );
}
}