Avoid passing string parameters by value in KeyPathMapping interface

src/realm/collection_parent.hpp

@@ -104,7 +104,6 @@ struct PathElement {
         , m_type(Type::index)
     {
     }
-
     PathElement(StringData str)
         : string_val(str)
         , m_type(Type::key)
@@ -115,6 +114,11 @@ struct PathElement {
         , m_type(Type::key)
     {
     }
+    PathElement(const std::string& str)
+        : string_val(str)
+        , m_type(Type::key)
+    {
+    }
     PathElement(const PathElement& other)
         : m_type(other.m_type)
     {

src/realm/obj.cpp

@@ -2201,7 +2201,7 @@ CollectionPtr Obj::get_collection_by_stable_path(const StablePath& path) const
             else {
                 std::string key = mpark::get<std::string>(index);
                 auto ref = dynamic_cast<Dictionary*>(collection.get())->get(key);
-                return {ref, StringData(key)};
+                return {ref, key};
             }
         };
         auto [ref, path_elem] = get_ref();

src/realm/parser/keypath_mapping.cpp

@@ -35,14 +35,14 @@ std::size_t TableAndColHash::operator()(const std::pair<TableKey, std::string>&
 }
 
 
-bool KeyPathMapping::add_mapping(ConstTableRef table, std::string name, std::string alias)
+bool KeyPathMapping::add_mapping(ConstTableRef table, const std::string& name, std::string alias)
 {
     auto table_key = table->get_key();
     auto it_and_success = m_mapping.insert({{table_key, name}, alias});
     return it_and_success.second;
 }
 
-bool KeyPathMapping::remove_mapping(ConstTableRef table, std::string name)
+bool KeyPathMapping::remove_mapping(ConstTableRef table, const std::string& name)
 {
     auto table_key = table->get_key();
     return m_mapping.erase({table_key, name}) > 0;
@@ -65,7 +65,7 @@ util::Optional<std::string> KeyPathMapping::get_mapping(TableKey table_key, cons
     return ret;
 }
 
-bool KeyPathMapping::add_table_mapping(ConstTableRef table, std::string alias)
+bool KeyPathMapping::add_table_mapping(ConstTableRef table, const std::string& alias)
 {
     std::string real_table_name = table->get_name();
     if (alias == real_table_name) {
@@ -75,7 +75,7 @@ bool KeyPathMapping::add_table_mapping(ConstTableRef table, std::string alias)
     return it_and_success.second;
 }
 
-bool KeyPathMapping::remove_table_mapping(std::string alias_to_remove)
+bool KeyPathMapping::remove_table_mapping(const std::string& alias_to_remove)
 {
     return m_table_mappings.erase(alias_to_remove) > 0;
 }
@@ -85,7 +85,7 @@ bool KeyPathMapping::has_table_mapping(const std::string& alias) const
     return m_table_mappings.count(alias) > 0;
 }
 
-util::Optional<std::string> KeyPathMapping::get_table_mapping(const std::string alias) const
+util::Optional<std::string> KeyPathMapping::get_table_mapping(const std::string& alias) const
 {
     if (auto it = m_table_mappings.find(alias); it != m_table_mappings.end()) {
         return it->second;
@@ -95,10 +95,10 @@ util::Optional<std::string> KeyPathMapping::get_table_mapping(const std::string
 
 constexpr static size_t max_substitutions_allowed = 50;
 
-std::string KeyPathMapping::translate_table_name(const std::string& identifier)
+std::string KeyPathMapping::translate_table_name(std::string_view identifier)
 {
     size_t substitutions = 0;
-    std::string alias = identifier;
+    std::string alias{identifier};
     while (auto mapped = get_table_mapping(alias)) {
         if (substitutions > max_substitutions_allowed) {
             throw MappingError(
@@ -115,11 +115,11 @@ std::string KeyPathMapping::translate_table_name(const std::string& identifier)
     return alias;
 }
 
-std::string KeyPathMapping::translate(ConstTableRef table, const std::string& identifier)
+std::string KeyPathMapping::translate(ConstTableRef table, std::string_view identifier)
 {
     size_t substitutions = 0;
     auto tk = table->get_key();
-    std::string alias = identifier;
+    std::string alias{identifier};
     while (auto mapped = get_mapping(tk, alias)) {
         if (substitutions > max_substitutions_allowed) {
             throw MappingError(
@@ -132,10 +132,10 @@ std::string KeyPathMapping::translate(ConstTableRef table, const std::string& id
     return alias;
 }
 
-std::string KeyPathMapping::translate(const LinkChain& link_chain, const std::string& identifier)
+std::string KeyPathMapping::translate(const LinkChain& link_chain, std::string_view identifier)
 {
     auto table = link_chain.get_current_table();
-    return translate(table, identifier);
+    return translate(table, std::string{identifier});
 }
 
 } // namespace query_parser

src/realm/parser/keypath_mapping.hpp

@@ -63,18 +63,20 @@ class KeyPathMapping {
 public:
     KeyPathMapping() = default;
     // returns true if added, false if duplicate key already exists
-    bool add_mapping(ConstTableRef table, std::string name, std::string alias);
-    bool remove_mapping(ConstTableRef table, std::string name);
+    bool add_mapping(ConstTableRef table, const std::string&, std::string alias);
+    bool remove_mapping(ConstTableRef table, const std::string&);
     bool has_mapping(ConstTableRef table, const std::string& name) const;
     util::Optional<std::string> get_mapping(TableKey table_key, const std::string& name) const;
     // table names are only used in backlink queries with the syntax '@links.TableName.property'
-    bool add_table_mapping(ConstTableRef table, std::string alias);
-    bool remove_table_mapping(std::string alias_to_remove);
+
+    bool add_table_mapping(ConstTableRef table, const std::string& alias);
+    bool remove_table_mapping(const std::string& alias_to_remove);
     bool has_table_mapping(const std::string& alias) const;
-    util::Optional<std::string> get_table_mapping(const std::string name) const;
-    std::string translate(const LinkChain&, const std::string& identifier);
-    std::string translate(ConstTableRef table, const std::string& identifier);
-    std::string translate_table_name(const std::string& identifier);
+    util::Optional<std::string> get_table_mapping(const std::string& name) const;
+
+    std::string translate(const LinkChain&, std::string_view identifier);
+    std::string translate(ConstTableRef table, std::string_view identifier);
+    std::string translate_table_name(std::string_view identifier);
 
 protected:
     std::unordered_map<std::pair<TableKey, std::string>, std::string, TableAndColHash> m_mapping;