neo4j_qt.py: refactor query transformation logic to dedicated file

1 files changed, 93 insertions, 0 deletions

diff --git a/src/server/neo4j_qt.py b/src/server/neo4j_qt.py
new file mode 100644
index 00000000..5bdb9604
--- /dev/null
+++ b/src/server/neo4j_qt.py
@@ -0,0 +1,93 @@
+from neo4j_cypher import Query_Struct_Type, DB_Query
+from neo4j_util import rzdoc__ns_label, rzdoc__meta_ns_label
+from neo4j_cypher_parser import p_path, p_node
+from db_op import DBO_rzdoc__clone, DB_op
+import re
+import neo4j_schema
+
+class Query_Transformation(object):
+    """
+    DB_op / DB_Query transformation
+    """
+
+    def __call__(self, value):
+        """
+        Apply transformation to either a DB_op or a DB_Query
+        """
+        if isinstance(value, DB_Query):
+            return self.apply_to_db_op(value)
+        if isinstance(value, DB_op):
+            return self.apply_to_db_op(value)
+
+    def apply_to_db_op(self, op):
+        for dbq in op: # apply to sub queries
+            self.apply_to_single_query(dbq)
+        return op
+
+    def apply_to_single_query(self, dbq): pass # subclass hook
+
+class QT_RZDOC_NS_Filter__common(Query_Transformation):
+    """
+    Add RZDoc name-space filter:
+       - inject NS labels into node patterns
+       - [!] ignore nodes which are part of path patterns to avoid overriding bound references
+    """
+
+    def __init__(self, ns_label):
+        self.ns_label = ns_label
+
+    def deco__process_q_ret__n_label_set(self, label_set):
+        ret = [lbl for lbl in label_set if lbl != self.ns_label]
+        return ret
+
+    def apply_to_db_op(self, op):
+        ret = Query_Transformation.apply_to_db_op(self, op)
+
+        # override DBO_rzdoc__clone.process_q_ret__n_label_set hook
+        if op.__class__ == DBO_rzdoc__clone:
+            op.process_q_ret__n_label_set = self.deco__process_q_ret__n_label_set
+
+        return ret
+
+    def apply_to_single_query(self, dbq):
+        q_type = dbq.query_struct_type
+        clause_set = []
+
+        if Query_Struct_Type.w == q_type:
+            clause_set += dbq.pt_root.clause_set_by_kw('create')
+        if Query_Struct_Type.r == q_type:
+            clause_set += dbq.pt_root.clause_set_by_kw('match')
+        if Query_Struct_Type.rw == q_type:
+            clause_set += dbq.pt_root.clause_set_by_kw('create')
+            clause_set += dbq.pt_root.clause_set_by_kw('match')
+
+        for c in clause_set:
+            n_exp_set = c.sub_exp_set_by_type(p_node, recurse=True)
+            for n_exp in n_exp_set:
+
+                if n_exp.parent.__class__ == p_path:
+                    continue;
+
+                lbl_set = n_exp.label_set
+                if not lbl_set:  # add label set if necessary
+                    lbl_set = n_exp.spawn_label_set()
+                lbl_set.add_label(self.ns_label)
+
+            # log.debug('db_q trans: in clause: %s, out clause: %s' % (cur_clause, new_clause))
+
+class QT_RZDOC_NS_Filter(QT_RZDOC_NS_Filter__common):
+
+    def __init__(self, rzdoc):
+        ns_label = rzdoc__ns_label(rzdoc)
+        super(QT_RZDOC_NS_Filter, self).__init__(ns_label)
+
+class QT_RZDOC_Meta_NS_Filter(QT_RZDOC_NS_Filter__common):
+
+    def __init__(self, rzdoc):
+        ns_label = rzdoc__meta_ns_label(rzdoc)
+        super(QT_RZDOC_Meta_NS_Filter, self).__init__(ns_label)
+
+class QT_Node_Filter__meta_label_set(Query_Transformation):
+    # TODO: impl
+    # 'where 0 = length(filter(_lbl in labels(n) where _lbl =~ \'^__.*$\'))',  # filter nodes with meta labels
+    pass