/includes/filerepo/backend/lockmanager/LockManager.php
PHP | 182 lines | 64 code | 18 blank | 100 comment | 2 complexity | b5894992d085cfb98ca55c05a1c2798c MD5 | raw file
Possible License(s): GPL-2.0, Apache-2.0, LGPL-3.0
- <?php
- /**
- * @defgroup LockManager Lock management
- * @ingroup FileBackend
- */
- /**
- * @file
- * @ingroup LockManager
- * @author Aaron Schulz
- */
- /**
- * Class for handling resource locking.
- *
- * Locks on resource keys can either be shared or exclusive.
- *
- * Implementations must keep track of what is locked by this proccess
- * in-memory and support nested locking calls (using reference counting).
- * At least LOCK_UW and LOCK_EX must be implemented. LOCK_SH can be a no-op.
- * Locks should either be non-blocking or have low wait timeouts.
- *
- * Subclasses should avoid throwing exceptions at all costs.
- *
- * @ingroup LockManager
- * @since 1.19
- */
- abstract class LockManager {
- /** @var Array Mapping of lock types to the type actually used */
- protected $lockTypeMap = array(
- self::LOCK_SH => self::LOCK_SH,
- self::LOCK_UW => self::LOCK_EX, // subclasses may use self::LOCK_SH
- self::LOCK_EX => self::LOCK_EX
- );
- /** @var Array Map of (resource path => lock type => count) */
- protected $locksHeld = array();
- /* Lock types; stronger locks have higher values */
- const LOCK_SH = 1; // shared lock (for reads)
- const LOCK_UW = 2; // shared lock (for reads used to write elsewhere)
- const LOCK_EX = 3; // exclusive lock (for writes)
- /**
- * Construct a new instance from configuration
- *
- * @param $config Array
- */
- public function __construct( array $config ) {}
- /**
- * Lock the resources at the given abstract paths
- *
- * @param $paths Array List of resource names
- * @param $type integer LockManager::LOCK_* constant
- * @return Status
- */
- final public function lock( array $paths, $type = self::LOCK_EX ) {
- return $this->doLock( array_unique( $paths ), $this->lockTypeMap[$type] );
- }
- /**
- * Unlock the resources at the given abstract paths
- *
- * @param $paths Array List of storage paths
- * @param $type integer LockManager::LOCK_* constant
- * @return Status
- */
- final public function unlock( array $paths, $type = self::LOCK_EX ) {
- return $this->doUnlock( array_unique( $paths ), $this->lockTypeMap[$type] );
- }
- /**
- * Get the base 36 SHA-1 of a string, padded to 31 digits
- *
- * @param $path string
- * @return string
- */
- final protected static function sha1Base36( $path ) {
- return wfBaseConvert( sha1( $path ), 16, 36, 31 );
- }
- /**
- * Lock resources with the given keys and lock type
- *
- * @param $paths Array List of storage paths
- * @param $type integer LockManager::LOCK_* constant
- * @return string
- */
- abstract protected function doLock( array $paths, $type );
- /**
- * Unlock resources with the given keys and lock type
- *
- * @param $paths Array List of storage paths
- * @param $type integer LockManager::LOCK_* constant
- * @return string
- */
- abstract protected function doUnlock( array $paths, $type );
- }
- /**
- * Self releasing locks
- *
- * LockManager helper class to handle scoped locks, which
- * release when an object is destroyed or goes out of scope.
- *
- * @ingroup LockManager
- * @since 1.19
- */
- class ScopedLock {
- /** @var LockManager */
- protected $manager;
- /** @var Status */
- protected $status;
- /** @var Array List of resource paths*/
- protected $paths;
- protected $type; // integer lock type
- /**
- * @param $manager LockManager
- * @param $paths Array List of storage paths
- * @param $type integer LockManager::LOCK_* constant
- * @param $status Status
- */
- protected function __construct(
- LockManager $manager, array $paths, $type, Status $status
- ) {
- $this->manager = $manager;
- $this->paths = $paths;
- $this->status = $status;
- $this->type = $type;
- }
- protected function __clone() {}
- /**
- * Get a ScopedLock object representing a lock on resource paths.
- * Any locks are released once this object goes out of scope.
- * The status object is updated with any errors or warnings.
- *
- * @param $manager LockManager
- * @param $paths Array List of storage paths
- * @param $type integer LockManager::LOCK_* constant
- * @param $status Status
- * @return ScopedLock|null Returns null on failure
- */
- public static function factory(
- LockManager $manager, array $paths, $type, Status $status
- ) {
- $lockStatus = $manager->lock( $paths, $type );
- $status->merge( $lockStatus );
- if ( $lockStatus->isOK() ) {
- return new self( $manager, $paths, $type, $status );
- }
- return null;
- }
- function __destruct() {
- $wasOk = $this->status->isOK();
- $this->status->merge( $this->manager->unlock( $this->paths, $this->type ) );
- if ( $wasOk ) {
- // Make sure status is OK, despite any unlockFiles() fatals
- $this->status->setResult( true, $this->status->value );
- }
- }
- }
- /**
- * Simple version of LockManager that does nothing
- * @since 1.19
- */
- class NullLockManager extends LockManager {
- protected function doLock( array $paths, $type ) {
- return Status::newGood();
- }
- protected function doUnlock( array $paths, $type ) {
- return Status::newGood();
- }
- }