trx_sys_read_wsrep_checkpoint(): Return whether a checkpoint is present

storage/innobase/include/trx0sys.h

@@ -255,11 +255,11 @@ trx_sys_update_wsrep_checkpoint(
 	trx_sysf_t*	sys_header,	/*!< in: sys_header */
 	mtr_t*		mtr);		/*!< in: mtr */
 
-void
-/** Read WSREP checkpoint XID from sys header. */
-trx_sys_read_wsrep_checkpoint(
-/*==========================*/
-	XID* xid); /*!< out: WSREP XID */
+/** Read WSREP checkpoint XID from sys header.
+@param[out]	xid	WSREP XID
+@return	whether the checkpoint was present */
+bool
+trx_sys_read_wsrep_checkpoint(XID* xid);
 #endif /* WITH_WSREP */
 
 /** Initializes the tablespace tag system. */

storage/innobase/trx/trx0sys.cc

@@ -349,10 +349,11 @@ trx_sys_update_wsrep_checkpoint(
 
 }
 
-void
-trx_sys_read_wsrep_checkpoint(
-/*==========================*/
-	XID* xid)
+/** Read WSREP checkpoint XID from sys header.
+@param[out]	xid	WSREP XID
+@return	whether the checkpoint was present */
+bool
+trx_sys_read_wsrep_checkpoint(XID* xid)
 {
 	trx_sysf_t*	sys_header;
 	mtr_t		mtr;
@@ -372,7 +373,7 @@ trx_sys_read_wsrep_checkpoint(
 		memcpy(xid->data + 24, &seqno, sizeof(long long));
 		xid->formatID = -1;
 		mtr_commit(&mtr);
-		return;
+		return false;
 	}
 
 	xid->formatID = (int)mach_read_from_4(
@@ -389,6 +390,7 @@ trx_sys_read_wsrep_checkpoint(
 		  XIDDATASIZE);
 
 	mtr_commit(&mtr);
+	return true;
 }
 
 #endif /* WITH_WSREP */