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diff --git a/includes/filerepo/backend/lockmanager/LockManager.php b/includes/filerepo/backend/lockmanager/LockManager.php
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+<?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();
+ }
+}