mdbx++: добавление перегрузок со std::string_view для методов open_map/create_map_/drop_map/clear_map/rename_map().

mdbx.h++

@@ -4353,6 +4353,37 @@ public:
   bool rename_map(const ::std::string &old_name, const ::std::string &new_name,
                   bool throw_if_absent = false);
 
+#if defined(DOXYGEN) ||                                                        \
+    (defined(__cpp_lib_string_view) && __cpp_lib_string_view >= 201606L)
+
+  /// \brief Open existing key-value map.
+  inline map_handle open_map(
+      const ::std::string_view &name,
+      const ::mdbx::key_mode key_mode = ::mdbx::key_mode::usual,
+      const ::mdbx::value_mode value_mode = ::mdbx::value_mode::single) const;
+  /// \brief Create new or open existing key-value map.
+  inline map_handle
+  create_map(const ::std::string_view &name,
+             const ::mdbx::key_mode key_mode = ::mdbx::key_mode::usual,
+             const ::mdbx::value_mode value_mode = ::mdbx::value_mode::single);
+  /// \brief Drop key-value map.
+  /// \return `True` if the key-value map existed and was deleted, either
+  /// `false` if the key-value map did not exist and there is nothing to delete.
+  bool drop_map(const ::std::string_view &name, bool throw_if_absent = false);
+  /// \return `True` if the key-value map existed and was cleared, either
+  /// `false` if the key-value map did not exist and there is nothing to clear.
+  bool clear_map(const ::std::string_view &name, bool throw_if_absent = false);
+  /// \brief Переименовывает таблицу ключ-значение.
+  inline void rename_map(map_handle map, const ::std::string_view &new_name);
+  /// \brief Переименовывает таблицу ключ-значение.
+  /// \return `True` если таблица существует и была переименована, либо
+  /// `false` в случае отсутствия исходной таблицы.
+  bool rename_map(const ::std::string_view &old_name,
+                  const ::std::string_view &new_name,
+                  bool throw_if_absent = false);
+
+#endif /* __cpp_lib_string_view >= 201606L */
+
   using map_stat = ::MDBX_stat;
   /// \brief Returns statistics for a sub-database.
   inline map_stat get_map_stat(map_handle map) const;
@@ -6294,12 +6325,6 @@ txn::open_map(const char *name, const ::mdbx::key_mode key_mode,
   return map;
 }
 
-inline ::mdbx::map_handle
-txn::open_map(const ::std::string &name, const ::mdbx::key_mode key_mode,
-              const ::mdbx::value_mode value_mode) const {
-  return open_map(name.c_str(), key_mode, value_mode);
-}
-
 inline ::mdbx::map_handle txn::create_map(const char *name,
                                           const ::mdbx::key_mode key_mode,
                                           const ::mdbx::value_mode value_mode) {
@@ -6312,36 +6337,102 @@ inline ::mdbx::map_handle txn::create_map(const char *name,
   return map;
 }
 
-inline ::mdbx::map_handle txn::create_map(const ::std::string &name,
-                                          const ::mdbx::key_mode key_mode,
-                                          const ::mdbx::value_mode value_mode) {
-  return create_map(name.c_str(), key_mode, value_mode);
-}
-
 inline void txn::drop_map(map_handle map) {
   error::success_or_throw(::mdbx_drop(handle_, map.dbi, true));
 }
 
-inline bool txn::drop_map(const ::std::string &name, bool throw_if_absent) {
-  return drop_map(name.c_str(), throw_if_absent);
-}
-
 inline void txn::clear_map(map_handle map) {
   error::success_or_throw(::mdbx_drop(handle_, map.dbi, false));
 }
 
-inline bool txn::clear_map(const ::std::string &name, bool throw_if_absent) {
-  return clear_map(name.c_str(), throw_if_absent);
-}
-
 inline void txn::rename_map(map_handle map, const char *new_name) {
   error::success_or_throw(::mdbx_dbi_rename(handle_, map, new_name));
 }
 
+#if defined(DOXYGEN) ||                                                        \
+    (defined(__cpp_lib_string_view) && __cpp_lib_string_view >= 201606L)
+
+inline ::mdbx::map_handle
+txn::open_map(const ::std::string_view &name, const ::mdbx::key_mode key_mode,
+              const ::mdbx::value_mode value_mode) const {
+  ::mdbx::map_handle map;
+  error::success_or_throw(::mdbx_dbi_open2(
+      handle_, ::mdbx::slice(name),
+      MDBX_db_flags_t(key_mode) | MDBX_db_flags_t(value_mode), &map.dbi));
+  assert(map.dbi != 0);
+  return map;
+}
+
+inline ::mdbx::map_handle txn::create_map(const ::std::string_view &name,
+                                          const ::mdbx::key_mode key_mode,
+                                          const ::mdbx::value_mode value_mode) {
+  ::mdbx::map_handle map;
+  error::success_or_throw(::mdbx_dbi_open2(
+      handle_, ::mdbx::slice(name),
+      MDBX_CREATE | MDBX_db_flags_t(key_mode) | MDBX_db_flags_t(value_mode),
+      &map.dbi));
+  assert(map.dbi != 0);
+  return map;
+}
+
+inline void txn::rename_map(map_handle map,
+                            const ::std::string_view &new_name) {
+  error::success_or_throw(
+      ::mdbx_dbi_rename2(handle_, map, ::mdbx::slice(new_name)));
+}
+
+inline ::mdbx::map_handle
+txn::open_map(const ::std::string &name, const ::mdbx::key_mode key_mode,
+              const ::mdbx::value_mode value_mode) const {
+  return open_map(::std::string_view(name), key_mode, value_mode);
+}
+
+inline ::mdbx::map_handle txn::create_map(const ::std::string &name,
+                                          const ::mdbx::key_mode key_mode,
+                                          const ::mdbx::value_mode value_mode) {
+  return create_map(::std::string_view(name), key_mode, value_mode);
+}
+
+inline bool txn::drop_map(const ::std::string &name, bool throw_if_absent) {
+  return drop_map(::std::string_view(name), throw_if_absent);
+}
+
+inline bool txn::clear_map(const ::std::string &name, bool throw_if_absent) {
+  return clear_map(::std::string_view(name), throw_if_absent);
+}
+
+inline void txn::rename_map(map_handle map, const ::std::string &new_name) {
+  return rename_map(map, ::std::string_view(new_name));
+}
+
+#else
+
+inline ::mdbx::map_handle
+txn::open_map(const ::std::string &name, const ::mdbx::key_mode key_mode,
+              const ::mdbx::value_mode value_mode) const {
+  return open_map(name.c_str(), key_mode, value_mode);
+}
+
+inline ::mdbx::map_handle txn::create_map(const ::std::string &name,
+                                          const ::mdbx::key_mode key_mode,
+                                          const ::mdbx::value_mode value_mode) {
+  return create_map(name.c_str(), key_mode, value_mode);
+}
+
+inline bool txn::drop_map(const ::std::string &name, bool throw_if_absent) {
+  return drop_map(name.c_str(), throw_if_absent);
+}
+
+inline bool txn::clear_map(const ::std::string &name, bool throw_if_absent) {
+  return clear_map(name.c_str(), throw_if_absent);
+}
+
 inline void txn::rename_map(map_handle map, const ::std::string &new_name) {
   return rename_map(map, new_name.c_str());
 }
 
+#endif /* __cpp_lib_string_view >= 201606L */
+
 inline txn::map_stat txn::get_map_stat(map_handle map) const {
   txn::map_stat r;
   error::success_or_throw(::mdbx_dbi_stat(handle_, map.dbi, &r, sizeof(r)));

src/mdbx.c++

@@ -1605,12 +1605,83 @@ __cold bool txn::rename_map(const char *old_name, const char *new_name,
   }
 }
 
+#if defined(__cpp_lib_string_view) && __cpp_lib_string_view >= 201606L
+
+__cold bool txn::drop_map(const ::std::string_view &name,
+                          bool throw_if_absent) {
+  map_handle map;
+  const int err =
+      ::mdbx_dbi_open2(handle_, mdbx::slice(name), MDBX_DB_ACCEDE, &map.dbi);
+  switch (err) {
+  case MDBX_SUCCESS:
+    drop_map(map);
+    return true;
+  case MDBX_NOTFOUND:
+  case MDBX_BAD_DBI:
+    if (!throw_if_absent)
+      return false;
+    MDBX_CXX17_FALLTHROUGH /* fallthrough */;
+  default:
+    MDBX_CXX20_UNLIKELY error::throw_exception(err);
+  }
+}
+
+__cold bool txn::clear_map(const ::std::string_view &name,
+                           bool throw_if_absent) {
+  map_handle map;
+  const int err =
+      ::mdbx_dbi_open2(handle_, mdbx::slice(name), MDBX_DB_ACCEDE, &map.dbi);
+  switch (err) {
+  case MDBX_SUCCESS:
+    clear_map(map);
+    return true;
+  case MDBX_NOTFOUND:
+  case MDBX_BAD_DBI:
+    if (!throw_if_absent)
+      return false;
+    MDBX_CXX17_FALLTHROUGH /* fallthrough */;
+  default:
+    MDBX_CXX20_UNLIKELY error::throw_exception(err);
+  }
+}
+
+__cold bool txn::rename_map(const ::std::string_view &old_name,
+                            const ::std::string_view &new_name,
+                            bool throw_if_absent) {
+  map_handle map;
+  const int err = ::mdbx_dbi_open2(handle_, mdbx::slice(old_name),
+                                   MDBX_DB_ACCEDE, &map.dbi);
+  switch (err) {
+  case MDBX_SUCCESS:
+    rename_map(map, new_name);
+    return true;
+  case MDBX_NOTFOUND:
+  case MDBX_BAD_DBI:
+    if (!throw_if_absent)
+      return false;
+    MDBX_CXX17_FALLTHROUGH /* fallthrough */;
+  default:
+    MDBX_CXX20_UNLIKELY error::throw_exception(err);
+  }
+}
+
+__cold bool txn::rename_map(const ::std::string &old_name,
+                            const ::std::string &new_name,
+                            bool throw_if_absent) {
+  return rename_map(::std::string_view(old_name), ::std::string_view(new_name),
+                    throw_if_absent);
+}
+
+#else
+
 __cold bool txn::rename_map(const ::std::string &old_name,
                             const ::std::string &new_name,
                             bool throw_if_absent) {
   return rename_map(old_name.c_str(), new_name.c_str(), throw_if_absent);
 }
 
+#endif /* __cpp_lib_string_view >= 201606L */
+
 //------------------------------------------------------------------------------
 
 void cursor_managed::close() {