Implement algo.cover

cpp/algo_module/algo_module.cpp

@@ -5,6 +5,9 @@
 extern "C" int mgp_init_module(struct mgp_module *module, struct mgp_memory *memory) {
   try {
     mgp::MemoryDispatcherGuard guard{memory};
+    AddProcedure(Algo::Cover, std::string(Algo::kProcedureCover).c_str(), mgp::ProcedureType::Read,
+                 {mgp::Parameter(std::string(Algo::kCoverArg1).c_str(), {mgp::Type::List, mgp::Type::Node})},
+                 {mgp::Return(std::string(Algo::kCoverRet1).c_str(), mgp::Type::Relationship)}, module, memory);
 
   } catch (const std::exception &e) {
     return 1;

cpp/algo_module/algorithm/algo.cpp

@@ -1 +1,28 @@
 #include "algo.hpp"
+
+void Algo::Cover(mgp_list *args, mgp_graph *memgraph_graph, mgp_result *result, mgp_memory *memory) {
+  mgp::MemoryDispatcherGuard guard{memory};
+  const auto arguments = mgp::List(args);
+  const auto record_factory = mgp::RecordFactory(result);
+  try {
+    auto list_nodes = arguments[0].ValueList();
+    std::unordered_set<mgp::Node> nodes;
+    for (const auto elem : list_nodes) {
+      auto node = elem.ValueNode();
+      nodes.insert(node);
+    }
+
+    for (auto node : nodes) {
+      for (auto rel : node.OutRelationships()) {
+        if (nodes.find(rel.To()) != nodes.end()) {
+          auto record = record_factory.NewRecord();
+          record.Insert(std::string(kCoverRet1).c_str(), rel);
+        }
+      }
+    }
+
+  } catch (const std::exception &e) {
+    record_factory.SetErrorMessage(e.what());
+    return;
+  }
+}

cpp/algo_module/algorithm/algo.hpp

@@ -1,5 +1,14 @@
 #pragma once
 
 #include <mgp.hpp>
+#include <unordered_set>
 
-namespace Algo {}  // namespace Algo
+namespace Algo {
+
+/* cover constants */
+constexpr std::string_view kProcedureCover = "cover";
+constexpr std::string_view kCoverArg1 = "nodes";
+constexpr std::string_view kCoverRet1 = "rel";
+
+void Cover(mgp_list *args, mgp_graph *memgraph_graph, mgp_result *result, mgp_memory *memory);
+}  // namespace Algo

e2e/algo_test/test_cover1/input.cyp

@@ -0,0 +1 @@
+CREATE (d:Dog),(h:Human),(ho:House), (d)-[l:LOVES]->(h),(h)-[:LIVES_IN]->(ho),(d)-[se:SELF_REL]->(d)

e2e/algo_test/test_cover1/test.yml

@@ -0,0 +1,9 @@
+query: >
+    MATCH (n)
+    WITH collect(n) AS list
+    CALL algo.cover(list) YIELD rel RETURN rel;
+
+output:
+    - rel: {'label': 'LIVES_IN','properties': {}}
+    - rel: {'label': 'LOVES','properties': {}}
+    - rel: {'label': 'SELF_REL','properties': {}}

e2e/algo_test/test_cover2/input.cyp

@@ -0,0 +1 @@
+CREATE (d:Dog),(h:Human),(ho:House), (d)-[l:LOVES]->(h),(h)-[:LIVES_IN]->(ho),(d)-[se:SELF_REL]->(d)

e2e/algo_test/test_cover2/test.yml

@@ -0,0 +1,6 @@
+query: >
+    MATCH (d:Dog)
+    CALL algo.cover([d]) YIELD rel RETURN rel;
+
+output:
+    - rel: {'label': 'SELF_REL','properties': {}}

e2e/algo_test/test_cover3/input.cyp

@@ -0,0 +1 @@
+MERGE (d:Dog {name: "Rex" ,id:0}) WITH d UNWIND range(0, 1000) AS id MERGE (h:Human {name: "Humie" + id, id:id}) MERGE (d)-[l:LOVES {id:id, how:"very"}]->(h);

e2e/algo_test/test_cover3/test.yml

@@ -0,0 +1,7 @@
+query: >
+  MATCH (n)
+  WITH collect(n) AS list
+  CALL algo.cover(list) YIELD rel RETURN count(rel) AS count;
+
+output:
+    - count: 1001