Merge pull request #1068 from daaku/c-purge-old-backups

rocksdb_backup_engine_purge_old_backups for C libraries

db/c.cc

@@ -446,6 +446,12 @@ void rocksdb_backup_engine_create_new_backup(rocksdb_backup_engine_t* be,
   SaveError(errptr, be->rep->CreateNewBackup(db->rep));
 }
 
+void rocksdb_backup_engine_purge_old_backups(rocksdb_backup_engine_t* be,
+                                             uint32_t num_backups_to_keep,
+                                             char** errptr) {
+  SaveError(errptr, be->rep->PurgeOldBackups(num_backups_to_keep));
+}
+
 rocksdb_restore_options_t* rocksdb_restore_options_create() {
   return new rocksdb_restore_options_t;
 }

db/c_test.c

@@ -365,6 +365,24 @@ int main(int argc, char** argv) {
     rocksdb_backup_engine_create_new_backup(be, db, &err);
     CheckNoError(err);
 
+    // need a change to trigger a new backup
+    rocksdb_delete(db, woptions, "does-not-exist", 14, &err);
+    CheckNoError(err);
+
+    rocksdb_backup_engine_create_new_backup(be, db, &err);
+    CheckNoError(err);
+
+    const rocksdb_backup_engine_info_t* bei = rocksdb_backup_engine_get_backup_info(be);
+    CheckCondition(rocksdb_backup_engine_info_count(bei) > 1);
+    rocksdb_backup_engine_info_destroy(bei);
+
+    rocksdb_backup_engine_purge_old_backups(be, 1, &err);
+    CheckNoError(err);
+
+    bei = rocksdb_backup_engine_get_backup_info(be);
+    CheckCondition(rocksdb_backup_engine_info_count(bei) == 1);
+    rocksdb_backup_engine_info_destroy(bei);
+
     rocksdb_delete(db, woptions, "foo", 3, &err);
     CheckNoError(err);
 

include/rocksdb/c.h

@@ -121,6 +121,9 @@ extern ROCKSDB_LIBRARY_API rocksdb_backup_engine_t* rocksdb_backup_engine_open(
 extern ROCKSDB_LIBRARY_API void rocksdb_backup_engine_create_new_backup(
     rocksdb_backup_engine_t* be, rocksdb_t* db, char** errptr);
 
+extern ROCKSDB_LIBRARY_API void rocksdb_backup_engine_purge_old_backups(
+    rocksdb_backup_engine_t* be, uint32_t num_backups_to_keep, char** errptr);
+
 extern ROCKSDB_LIBRARY_API rocksdb_restore_options_t*
 rocksdb_restore_options_create();
 extern ROCKSDB_LIBRARY_API void rocksdb_restore_options_destroy(