From 972c50e10e3727d697457299ae71918c1f444af5 Mon Sep 17 00:00:00 2001
From: LV-426 <lv-426@taproot.org.il>
Date: Wed, 29 Apr 2015 03:51:44 +0300
Subject: db_op: DBO_rzdb__fetch_DB_metablock

---
 src/server/db_op.py | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

(limited to 'src/server')

diff --git a/src/server/db_op.py b/src/server/db_op.py
index f28dc320..aa0046a0 100644
--- a/src/server/db_op.py
+++ b/src/server/db_op.py
@@ -716,6 +716,29 @@ class DBO_rm_link_set(DB_op):
         q_params = {'id_set': id_set}
         self.add_statement(q_arr, q_params)
 
+class DBO_rzdb__fetch_DB_metablock(DB_op):
+
+    def __init__(self, length_lim=None):
+        """
+        Fetch DB metadata
+
+        @retrun metablock or None if none was found
+        """
+        super(DBO_rzdb__fetch_DB_metablock, self).__init__()
+
+        q_arr = ['match (n:%s)' % (neo4j_schema.META_LABEL__RZDB_META),
+                 'return n'
+                 ]
+        self.add_statement(q_arr)
+
+    def process_result_set(self):
+        ret = super(DBO_rzdb__fetch_DB_metablock, self).process_result_set()
+        if len(ret) > 1:  # assert DB contains single metablock
+            raise Exception('found more than one DB metablocks, DB may be corrupt')
+        if 0 == len(ret):
+            return None
+        return ret.pop()
+
 class DBO_rzdoc__clone(DB_op):
 
     def __init__(self, limit=16384):
-- 
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