Initial doxygen comments on Db and Graph classes

Summary: Initial doxygen comments on Db and Graph classes

Test Plan: manual

Reviewers: sale

Subscribers: sale, buda

Differential Revision: https://memgraph.phacility.com/D23

include/database/db.hpp

@@ -10,44 +10,85 @@
 
 class Indexes;
 
-// Main class which represents Database concept in code.
 // TODO: Maybe split this in another layer between Db and Dbms. Where the new
 // layer would hold SnapshotEngine and his kind of concept objects. Some
 // guidelines would be: retain objects which are necessary to implement querys
 // in Db, the rest can be moved to the new layer.
+
+/**
+ * Main class which represents Database concept in code.
+ */
 class Db
 {
 public:
     using sptr = std::shared_ptr<Db>;
 
-    // import_snapshot will in constructor import latest snapshot into the db.
-    // NOTE: explicit is here to prevent compiler from evaluating const char *
-    // into a bool.
+    /**
+     * This constructor will create a database with the name "default"
+     *
+     * NOTE: explicit is here to prevent compiler from evaluating const char *
+     * into a bool.
+     *
+     * @param import_snapshot will in constructor import latest snapshot
+     *                        into the db.
+     */
     explicit Db(bool import_snapshot = true);
 
-    // import_snapshot will in constructor import latest snapshot into the db.
+    /**
+     * Construct database with a custom name.
+     *
+     * @param name database name
+     * @param import_snapshot will in constructor import latest snapshot
+     *                        into the db.
+     */
     Db(const char *name, bool import_snapshot = true);
 
-    // import_snapshot will in constructor import latest snapshot into the db.
+    /**
+     * Construct database with a custom name.
+     *
+     * @param name database name
+     * @param import_snapshot will in constructor import latest snapshot
+     *                        into the db.
+     */
     Db(const std::string &name, bool import_snapshot = true);
 
+    /**
+     * Database object can't be copied.
+     */
     Db(const Db &db) = delete;
 
 private:
+    /** database name */
     const std::string name_;
 
 public:
+    /** transaction engine related to this database */
     tx::Engine tx_engine;
+
+    /** graph related to this database */
     Graph graph;
+
+    /** garbage collector related to this database*/
     Garbage garbage = {tx_engine};
 
-    // This must be initialized after name.
+    /**
+     * snapshot engine related to this database
+     *
+     * \b IMPORTANT: has to be initialized after name
+     * */
     SnapshotEngine snap_engine = {*this};
 
-    // Creates Indexes for this db.
+    /**
+     * Creates Indexes for this database.
+     */
+    Indexes indexes();
     // TODO: Indexes should be created only once somwhere Like Db or layer
     // between Db and Dbms.
-    Indexes indexes();
 
+    /**
+     * Returns a name of the database.
+     *
+     * @return database name
+     */
     std::string const &name() const;
 };

include/storage/graph.hpp

@@ -5,14 +5,28 @@
 #include "storage/label/label_store.hpp"
 #include "storage/vertices.hpp"
 
+/**
+ * Graph storage. Contains vertices and edges, labels and edges.
+ */
 class Graph
 {
 public:
-    Graph() {}
+    /**
+     * default constructor 
+     *
+     * At the beginning the graph is empty.
+     */
+    Graph() = default;
 
+    /** storage for all vertices related to this graph */
     Vertices vertices;
+
+    /** storage for all edges related to this graph */
     Edges edges;
 
+    /** storage for all labels */
     LabelStore label_store;
+
+    /** storage for all types related for this graph */
     EdgeTypeStore edge_type_store;
 };