Implemented label.exists procedure

Author: idoraban

cpp/CMakeLists.txt

@@ -148,4 +148,5 @@ add_subdirectory(periodic_module)
 add_subdirectory(map_module)
 add_subdirectory(collections_module)
 add_subdirectory(text_module)
+add_subdirectory(label_module)
 add_cugraph_subdirectory(cugraph_module)

cpp/label_module/CMakeLists.txt

@@ -0,0 +1,5 @@
+set(label_module_src
+    label_module.cpp
+    algorithm/label.cpp)
+
+add_query_module(label 1 "${label_module_src}")

cpp/label_module/algorithm/label.cpp

@@ -0,0 +1,23 @@
+#include "label.hpp"
+
+void Label::Exists(mgp_list *args, mgp_graph *memgraph_graph, mgp_result *result, mgp_memory *memory) {
+  mgp::memory = memory;
+  const auto arguments = mgp::List(args);
+  const auto record_factory = mgp::RecordFactory(result);
+  try {
+    bool exists = false;
+
+    const auto label = arguments[1].ValueString();
+    if (arguments[0].IsNode()) {
+      const auto node = arguments[0].ValueNode();
+      exists = node.HasLabel(label);
+    }
+
+    auto record = record_factory.NewRecord();
+    record.Insert(std::string(kResultExists).c_str(), std::move(exists));
+
+  } catch (const std::exception &e) {
+    record_factory.SetErrorMessage(e.what());
+    return;
+  }
+}

cpp/label_module/algorithm/label.hpp

@@ -0,0 +1,16 @@
+#pragma once
+
+#include <mgp.hpp>
+
+namespace Label {
+
+/* exists constants */
+constexpr std::string_view kReturnExists = "exists";
+constexpr std::string_view kProcedureExists = "exists";
+constexpr std::string_view kArgumentsNode = "node";
+constexpr std::string_view kArgumentsLabel = "label";
+constexpr std::string_view kResultExists = "exists";
+
+void Exists(mgp_list *args, mgp_graph *memgraph_graph, mgp_result *result, mgp_memory *memory);
+
+}  // namespace Label

cpp/label_module/label_module.cpp

@@ -0,0 +1,20 @@
+#include <mgp.hpp>
+
+#include "algorithm/label.hpp"
+
+extern "C" int mgp_init_module(struct mgp_module *module, struct mgp_memory *memory) {
+  try {
+    mgp::memory = memory;
+    AddProcedure(Label::Exists, Label::kProcedureExists, mgp::ProcedureType::Read,
+                 {mgp::Parameter(Label::kArgumentsNode, mgp::Type::Any),
+                  mgp::Parameter(Label::kArgumentsLabel, mgp::Type::String)},
+                 {mgp::Return(Label::kReturnExists, mgp::Type::Bool)}, module, memory);
+
+  } catch (const std::exception &e) {
+    return 1;
+  }
+
+  return 0;
+}
+
+extern "C" int mgp_shutdown_module() { return 0; }

e2e/label_test/test_exists_false/input.cyp

@@ -0,0 +1 @@
+CREATE (s1:Student {name: 'Ana'});

e2e/label_test/test_exists_false/test.yml

@@ -0,0 +1,7 @@
+query: >
+  MATCH (s1:Student {name: 'Ana'})
+  CALL label.exists(s1, "Teacher") YIELD exists
+  RETURN exists
+
+output:
+  - exists: False

e2e/label_test/test_exists_not_node/input.cyp

@@ -0,0 +1 @@
+MERGE (s1:Student {name: 'Ana'}) MERGE (s2:Student {name: 'Marija'}) CREATE (s1)-[k:KNOWS]->(s2);

e2e/label_test/test_exists_not_node/test.yml

@@ -0,0 +1,7 @@
+query: >
+  MATCH (:Student)-[k:KNOWS]->(:Student)
+  CALL label.exists(k, "Knows") YIELD exists
+  RETURN exists
+
+output:
+  - exists: False

e2e/label_test/test_exists_true/input.cyp

@@ -0,0 +1 @@
+CREATE (s1:Student {name: 'Ana'});