2 files changed, 89 insertions, 8 deletions

diff --git a/includes/filebackend/filejournal/DBFileJournal.php b/includes/filebackend/filejournal/DBFileJournal.php
index f6268c25..73f29a95 100644
--- a/includes/filebackend/filejournal/DBFileJournal.php
+++ b/includes/filebackend/filejournal/DBFileJournal.php
@@ -75,6 +75,9 @@ class DBFileJournal extends FileJournal {
 
 		try {
 			$dbw->insert( 'filejournal', $data, __METHOD__ );
+			if ( mt_rand( 0, 99 ) == 0 ) {
+				$this->purgeOldLogs(); // occasionally delete old logs
+			}
 		} catch ( DBError $e ) {
 			$status->fatal( 'filejournal-fail-dbquery', $this->backend );
 			return $status;
@@ -84,6 +87,35 @@ class DBFileJournal extends FileJournal {
 	}
 
 	/**
+	 * @see FileJournal::doGetCurrentPosition()
+	 * @return integer|false
+	 */
+	protected function doGetCurrentPosition() {
+		$dbw = $this->getMasterDB();
+
+		return $dbw->selectField( 'filejournal', 'MAX(fj_id)',
+			array( 'fj_backend' => $this->backend ),
+			__METHOD__
+		);
+	}
+
+	/**
+	 * @see FileJournal::doGetPositionAtTime()
+	 * @param $time integer|string timestamp
+	 * @return integer|false
+	 */
+	protected function doGetPositionAtTime( $time ) {
+		$dbw = $this->getMasterDB();
+
+		$encTimestamp = $dbw->addQuotes( $dbw->timestamp( $time ) );
+		return $dbw->selectField( 'filejournal', 'fj_id',
+			array( 'fj_backend' => $this->backend, "fj_timestamp <= $encTimestamp" ),
+			__METHOD__,
+			array( 'ORDER BY' => 'fj_timestamp DESC' )
+		);
+	}
+
+	/**
 	 * @see FileJournal::doGetChangeEntries()
 	 * @return Array
 	 * @throws DBError
diff --git a/includes/filebackend/filejournal/FileJournal.php b/includes/filebackend/filejournal/FileJournal.php
index ce029bbe..a1b7a459 100644
--- a/includes/filebackend/filejournal/FileJournal.php
+++ b/includes/filebackend/filejournal/FileJournal.php
@@ -54,7 +54,7 @@ abstract class FileJournal {
 	 * Create an appropriate FileJournal object from config
 	 *
 	 * @param $config Array
-	 * @param $backend string A registered file backend name
+	 * @param string $backend A registered file backend name
 	 * @throws MWException
 	 * @return FileJournal
 	 */
@@ -85,13 +85,13 @@ abstract class FileJournal {
 	/**
 	 * Log changes made by a batch file operation.
 	 * $entries is an array of log entries, each of which contains:
-	 *     op      : Basic operation name (create, store, copy, delete)
+	 *     op      : Basic operation name (create, update, delete)
 	 *     path    : The storage path of the file
 	 *     newSha1 : The final base 36 SHA-1 of the file
 	 * Note that 'false' should be used as the SHA-1 for non-existing files.
 	 *
-	 * @param $entries Array List of file operations (each an array of parameters)
-	 * @param $batchId string UUID string that identifies the operation batch
+	 * @param array $entries List of file operations (each an array of parameters)
+	 * @param string $batchId UUID string that identifies the operation batch
 	 * @return Status
 	 */
 	final public function logChangeBatch( array $entries, $batchId ) {
@@ -104,13 +104,45 @@ abstract class FileJournal {
 	/**
 	 * @see FileJournal::logChangeBatch()
 	 *
-	 * @param $entries Array List of file operations (each an array of parameters)
-	 * @param $batchId string UUID string that identifies the operation batch
+	 * @param array $entries List of file operations (each an array of parameters)
+	 * @param string $batchId UUID string that identifies the operation batch
 	 * @return Status
 	 */
 	abstract protected function doLogChangeBatch( array $entries, $batchId );
 
 	/**
+	 * Get the position ID of the latest journal entry
+	 *
+	 * @return integer|false
+	 */
+	final public function getCurrentPosition() {
+		return $this->doGetCurrentPosition();
+	}
+
+	/**
+	 * @see FileJournal::getCurrentPosition()
+	 * @return integer|false
+	 */
+	abstract protected function doGetCurrentPosition();
+
+	/**
+	 * Get the position ID of the latest journal entry at some point in time
+	 *
+	 * @param $time integer|string timestamp
+	 * @return integer|false
+	 */
+	final public function getPositionAtTime( $time ) {
+		return $this->doGetPositionAtTime( $time );
+	}
+
+	/**
+	 * @see FileJournal::getPositionAtTime()
+	 * @param $time integer|string timestamp
+	 * @return integer|false
+	 */
+	abstract protected function doGetPositionAtTime( $time );
+
+	/**
 	 * Get an array of file change log entries.
 	 * A starting change ID and/or limit can be specified.
 	 *
@@ -169,7 +201,7 @@ abstract class FileJournal {
  */
 class NullFileJournal extends FileJournal {
 	/**
-	 * @see FileJournal::logChangeBatch()
+	 * @see FileJournal::doLogChangeBatch()
 	 * @param $entries array
 	 * @param $batchId string
 	 * @return Status
@@ -179,6 +211,23 @@ class NullFileJournal extends FileJournal {
 	}
 
 	/**
+	 * @see FileJournal::doGetCurrentPosition()
+	 * @return integer|false
+	 */
+	protected function doGetCurrentPosition() {
+		return false;
+	}
+
+	/**
+	 * @see FileJournal::doGetPositionAtTime()
+	 * @param $time integer|string timestamp
+	 * @return integer|false
+	 */
+	protected function doGetPositionAtTime( $time ) {
+		return false;
+	}
+
+	/**
 	 * @see FileJournal::doGetChangeEntries()
 	 * @return Array
 	 */
@@ -187,7 +236,7 @@ class NullFileJournal extends FileJournal {
 	}
 
 	/**
-	 * @see FileJournal::purgeOldLogs()
+	 * @see FileJournal::doPurgeOldLogs()
 	 * @return Status
 	 */
 	protected function doPurgeOldLogs() {