X-Git-Url: http://git.cyclocoop.org/?a=blobdiff_plain;f=includes%2Fdao%2FDBAccessObjectUtils.php;h=ee1036852172f955aa51ecfb53895b82b151afaf;hb=d6b0b9253544dae85d95e8f7e02c8d6a13a6fef4;hp=ad7804c21b52e418457e781f2019d5dc17e5735f;hpb=0e81e2108a7e088991249c72bd31786f45246366;p=lhc%2Fweb%2Fwiklou.git

diff --git a/includes/dao/DBAccessObjectUtils.php b/includes/dao/DBAccessObjectUtils.php
index ad7804c21b..ee10368521 100644
--- a/includes/dao/DBAccessObjectUtils.php
+++ b/includes/dao/DBAccessObjectUtils.php
@@ -26,10 +26,10 @@
  *
  * @since 1.26
  */
-class DBAccessObjectUtils {
+class DBAccessObjectUtils implements IDBAccessObject {
 	/**
-	 * @param integer $bitfield
-	 * @param integer $flags IDBAccessObject::READ_* constant
+	 * @param int $bitfield
+	 * @param int $flags IDBAccessObject::READ_* constant
 	 * @return bool Bitfield has flag $flag set
 	 */
 	public static function hasFlags( $bitfield, $flags ) {
@@ -37,23 +37,45 @@ class DBAccessObjectUtils {
 	}
 
 	/**
-	 * Get an appropriate DB index and options for a query
+	 * Get an appropriate DB index, options, and fallback DB index for a query
 	 *
-	 * @param integer $bitfield
-	 * @return array (DB_MASTER/DB_SLAVE, SELECT options array)
+	 * The fallback DB index and options are to be used if the entity is not found
+	 * with the initial DB index, typically querying the master DB to avoid lag
+	 *
+	 * @param int $bitfield Bitfield of IDBAccessObject::READ_* constants
+	 * @return array List of DB indexes and options in this order:
+	 *   - DB_MASTER or DB_REPLICA constant for the initial query
+	 *   - SELECT options array for the initial query
+	 *   - DB_MASTER constant for the fallback query; null if no fallback should happen
+	 *   - SELECT options array for the fallback query; empty if no fallback should happen
 	 */
 	public static function getDBOptions( $bitfield ) {
-		$index = self::hasFlags( $bitfield, IDBAccessObject::READ_LATEST )
-			? DB_MASTER
-			: DB_SLAVE;
+		if ( self::hasFlags( $bitfield, self::READ_LATEST_IMMUTABLE ) ) {
+			$index = DB_REPLICA; // override READ_LATEST if set
+			$fallbackIndex = DB_MASTER;
+		} elseif ( self::hasFlags( $bitfield, self::READ_LATEST ) ) {
+			$index = DB_MASTER;
+			$fallbackIndex = null;
+		} else {
+			$index = DB_REPLICA;
+			$fallbackIndex = null;
+		}
+
+		$lockingOptions = [];
+		if ( self::hasFlags( $bitfield, self::READ_EXCLUSIVE ) ) {
+			$lockingOptions[] = 'FOR UPDATE';
+		} elseif ( self::hasFlags( $bitfield, self::READ_LOCKING ) ) {
+			$lockingOptions[] = 'LOCK IN SHARE MODE';
+		}
 
-		$options = array();
-		if ( self::hasFlags( $bitfield, IDBAccessObject::READ_EXCLUSIVE ) ) {
-			$options[] = 'FOR UPDATE';
-		} elseif ( self::hasFlags( $bitfield, IDBAccessObject::READ_LOCKING ) ) {
-			$options[] = 'LOCK IN SHARE MODE';
+		if ( $fallbackIndex !== null ) {
+			$options = []; // locks on DB_REPLICA make no sense
+			$fallbackOptions = $lockingOptions;
+		} else {
+			$options = $lockingOptions;
+			$fallbackOptions = []; // no fallback
 		}
 
-		return array( $index, $options );
+		return [ $index, $options, $fallbackIndex, $fallbackOptions ];
 	}
 }