From adedb662790fb2768d9d258dc1c7a44ac85b49b4 Mon Sep 17 00:00:00 2001
From: Aaron Schulz <aschulz@wikimedia.org>
Date: Sat, 28 Apr 2012 12:49:46 -0700
Subject: [PATCH] [FileBackend] Added getScopedLocksForOps() function.

This lets callers safely change files *and* update DB data.

Change-Id: I6ec70e98b1535528b756e109b8b28e4a3e839552
---
 includes/filerepo/backend/FileBackend.php      | 18 ++++++++++++++++++
 .../filerepo/backend/FileBackendMultiWrite.php | 16 ++++++++++++++++
 includes/filerepo/backend/FileBackendStore.php | 12 ++++++++++++
 3 files changed, 46 insertions(+)

diff --git a/includes/filerepo/backend/FileBackend.php b/includes/filerepo/backend/FileBackend.php
index 544c9c28dc..59ca04d43a 100644
--- a/includes/filerepo/backend/FileBackend.php
+++ b/includes/filerepo/backend/FileBackend.php
@@ -682,6 +682,24 @@ abstract class FileBackend {
 		return ScopedLock::factory( $this->lockManager, $paths, $type, $status );
 	}
 
+	/**
+	 * Get an array of scoped locks needed for a batch of file operations.
+	 *
+	 * Normally, FileBackend::doOperations() handles locking, unless
+	 * the 'nonLocking' param is passed in. This function is useful if you
+	 * want the files to be locked for a broader scope than just when the
+	 * files are changing. For example, if you need to update DB metadata,
+	 * you may want to keep the files locked until finished.
+	 *
+	 * @see FileBackend::doOperations()
+	 *
+	 * @param $ops Array List of file operations to FileBackend::doOperations()
+	 * @param $status Status Status to update on lock/unlock
+	 * @return Array List of ScopedFileLocks or null values
+	 * @since 1.20
+	 */
+	abstract public function getScopedLocksForOps( array $ops, Status $status );
+
 	/**
 	 * Get the root storage path of this backend.
 	 * All container paths are "subdirectories" of this path.
diff --git a/includes/filerepo/backend/FileBackendMultiWrite.php b/includes/filerepo/backend/FileBackendMultiWrite.php
index 208d34b6ad..7f2c5b7b37 100644
--- a/includes/filerepo/backend/FileBackendMultiWrite.php
+++ b/includes/filerepo/backend/FileBackendMultiWrite.php
@@ -434,4 +434,20 @@ class FileBackendMultiWrite extends FileBackend {
 			$backend->clearCache( $realPaths );
 		}
 	}
+
+	/**
+	 * @see FileBackend::getScopedLocksForOps()
+	 */
+	public function getScopedLocksForOps( array $ops, Status $status ) {
+		$fileOps = $this->backends[$this->masterIndex]->getOperationsInternal( $ops );
+		// Get the paths to lock from the master backend
+		$paths = $this->backends[$this->masterIndex]->getPathsToLockForOpsInternal( $fileOps );
+		// Get the paths under the proxy backend's name
+		$paths['sh'] = $this->unsubstPaths( $paths['sh'] );
+		$paths['ex'] = $this->unsubstPaths( $paths['ex'] );
+		return array(
+			$this->getScopedFileLocks( $paths['sh'], LockManager::LOCK_UW, $status ),
+			$this->getScopedFileLocks( $paths['ex'], LockManager::LOCK_EX, $status )
+		);
+	}
 }
diff --git a/includes/filerepo/backend/FileBackendStore.php b/includes/filerepo/backend/FileBackendStore.php
index fab62e5bd2..d091da91e5 100644
--- a/includes/filerepo/backend/FileBackendStore.php
+++ b/includes/filerepo/backend/FileBackendStore.php
@@ -856,6 +856,18 @@ abstract class FileBackendStore extends FileBackend {
 		return $paths;
 	}
 
+	/**
+	 * @see FileBackend::getScopedLocksForOps()
+	 * @return Array
+	 */
+	public function getScopedLocksForOps( array $ops, Status $status ) {
+		$paths = $this->getPathsToLockForOpsInternal( $this->getOperationsInternal( $ops ) );
+		return array(
+			$this->getScopedFileLocks( $paths['sh'], LockManager::LOCK_UW, $status ),
+			$this->getScopedFileLocks( $paths['ex'], LockManager::LOCK_EX, $status )
+		);
+	}
+
 	/**
 	 * @see FileBackend::doOperationsInternal()
 	 * @return Status
-- 
2.20.1