Serialize Ast via SLK

Reviewers: mtomic, llugovic

Reviewed By: mtomic

Subscribers: pullbot

Differential Revision: https://phabricator.memgraph.io/D1764

src/query/frontend/ast/ast_serialization.lcp

@@ -1,6 +1,8 @@
 #>cpp
 #pragma once
 
+#include <type_traits>
+
 #include "query/frontend/ast/ast.hpp"
 #include "query/frontend/ast/ast_serialization.capnp.h"
 #include "query/serialization.hpp"
@@ -12,12 +14,72 @@ cpp<#
 (lcp:namespace query)
 
 #>cpp
+/// Primary function for saving Ast nodes via SLK.
+void SaveAstPointer(const Tree *ast, slk::Builder *builder,
+                    std::vector<int32_t> *saved_uids);
+
 Tree *Load(AstStorage *ast, const capnp::Tree::Reader &tree,
-           std::vector<int> *loaded_uids);
+           std::vector<int32_t> *loaded_uids);
+
+Tree *Load(AstStorage *ast, slk::Reader *reader,
+           std::vector<int32_t> *loaded_uids);
+
+/// Primary function for loading Ast nodes via SLK.
+template <class TAst>
+TAst *LoadAstPointer(AstStorage *ast, slk::Reader *reader,
+                     std::vector<int32_t> *loaded_uids) {
+  static_assert(std::is_base_of<query::Tree, TAst>::value);
+  bool has_ptr = false;
+  slk::Load(&has_ptr, reader);
+  if (!has_ptr) {
+    return nullptr;
+  }
+  auto *ret = dynamic_cast<TAst *>(Load(ast, reader, loaded_uids));
+  if (!ret) {
+    throw slk::SlkDecodeException("Loading unknown Ast node type");
+  }
+  return ret;
+}
 cpp<#
 
 (lcp:in-impl
   #>cpp
+  void SaveAstPointer(const Tree *ast, slk::Builder *builder,
+                      std::vector<int32_t> *saved_uids) {
+    slk::Save(static_cast<bool>(ast), builder);
+    if (!ast) {
+      return;
+    }
+    slk::Save(ast->uid_, builder);
+    if (utils::Contains(*saved_uids, ast->uid_)) {
+      return;
+    }
+    slk::Save(*ast, builder, saved_uids);
+    CHECK(!utils::Contains(*saved_uids, ast->uid_)) << "Serializing cyclic AST";
+    saved_uids->push_back(ast->uid_);
+  }
+
+  Tree *Load(AstStorage *ast, slk::Reader *reader,
+             std::vector<int32_t> *loaded_uids) {
+    // Check if element already deserialized and if yes, return existing
+    // element from storage.
+    int32_t uid;
+    slk::Load(&uid, reader);
+    if (utils::Contains(*loaded_uids, uid)) {
+      auto found = std::find_if(ast->storage_.begin(), ast->storage_.end(),
+                                [&](const auto &n) { return n->uid_ == uid; });
+      CHECK(found != ast->storage_.end());
+      return found->get();
+    }
+    std::unique_ptr<Tree> root;
+    slk::ConstructAndLoad(&root, reader, ast, loaded_uids);
+    root->uid_ = uid;
+    ast->storage_.emplace_back(std::move(root));
+    loaded_uids->push_back(uid);
+    ast->max_existing_uid_ = std::max(ast->max_existing_uid_, uid);
+    return ast->storage_.back().get();
+  }
+
   Tree *Load(AstStorage *ast, const capnp::Tree::Reader &tree,
              std::vector<int> *loaded_uids) {
     // Check if element already deserialized and if yes, return existing

tests/unit/CMakeLists.txt

@@ -19,6 +19,9 @@ function(add_unit_test test_cpp)
   add_dependencies(memgraph__unit ${target_name})
 endfunction(add_unit_test)
 
+add_unit_test(ast_serialization.cpp)
+target_link_libraries(${test_prefix}ast_serialization mg-distributed kvstore_dummy_lib)
+
 add_unit_test(bolt_encoder.cpp)
 target_link_libraries(${test_prefix}bolt_encoder mg-single-node kvstore_dummy_lib)
 

tests/unit/cypher_main_visitor.cpp

@@ -11,17 +11,11 @@
 
 #include "query/context.hpp"
 #include "query/frontend/ast/ast.hpp"
-// TODO: FIXME
-// #include "query/frontend/ast/ast_serialization.hpp"
 #include "query/frontend/ast/cypher_main_visitor.hpp"
 #include "query/frontend/opencypher/parser.hpp"
 #include "query/frontend/stripped.hpp"
 #include "query/typed_value.hpp"
 
-// TODO: FIXME
-// #include "capnp/message.h"
-// #include "query/frontend/ast/ast_serialization.capnp.h"
-
 namespace {
 
 using namespace query;
@@ -140,52 +134,13 @@ class CachedAstGenerator : public Base {
   Query *query_;
 };
 
-/* TODO: FIXME
-class CapnpAstGenerator : public Base {
- public:
-  CapnpAstGenerator(const std::string &query)
-      : Base(query),
-        storage_([&]() {
-          ::frontend::opencypher::Parser parser(query);
-          CypherMainVisitor visitor(context_, db_accessor_.get());
-          visitor.visit(parser.tree());
-
-          ::capnp::MallocMessageBuilder message;
-          {
-            query::capnp::Tree::Builder builder =
-                message.initRoot<query::capnp::Tree>();
-            std::vector<int> saved_uids;
-            Save(*visitor.query(), &builder, &saved_uids);
-          }
-
-          AstStorage new_ast;
-          {
-            const query::capnp::Tree::Reader reader =
-                message.getRoot<query::capnp::Tree>();
-            std::vector<int> loaded_uids;
-            Load(&new_ast, reader, &loaded_uids);
-          }
-          return new_ast;
-        }()),
-        query_(storage_.query()) {}
-
-  AstStorage storage_;
-  Query *query_;
-};
-*/
-
 template <typename T>
 class CypherMainVisitorTest : public ::testing::Test {};
 
-/* TODO: FIXME I have removed `CapnpAstGenerator` from the lower list
-typedef ::testing::Types<AstGenerator, OriginalAfterCloningAstGenerator,
-                         ClonedAstGenerator, CachedAstGenerator,
-                         CapnpAstGenerator>
-    AstGeneratorTypes;
-*/
 typedef ::testing::Types<AstGenerator, OriginalAfterCloningAstGenerator,
                          ClonedAstGenerator, CachedAstGenerator>
     AstGeneratorTypes;
+
 TYPED_TEST_CASE(CypherMainVisitorTest, AstGeneratorTypes);
 
 TYPED_TEST(CypherMainVisitorTest, SyntaxException) {