AK+Userland: Introduce ByteString::create_and_overwrite

And replace two users of raw StringImpl with it.
lanmonster · Feb 24, 2024 · 061f902 · 061f902
1 parent f7c952f
commit 061f902
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Showing 3 changed files with 28 additions and 12 deletions.
diff --git a/AK/ByteString.h b/AK/ByteString.h
@@ -93,6 +93,23 @@ class ByteString {
  static ByteString must_from_utf8(StringView string) { return MUST(from_utf8(string)); }
  static ByteString from_utf8_without_validation(StringView string) { return ByteString { string }; }
 
+ template<
+ typename F,
+ typename PossiblyErrorOr = decltype(declval<F>()(declval<Bytes>())),
+ bool is_error_or = IsSpecializationOf<PossiblyErrorOr, ErrorOr>,
+ typename ReturnType = Conditional<is_error_or, ErrorOr<ByteString>, ByteString>>
+ static ReturnType create_and_overwrite(size_t length, F&& fill_function)
+ {
+ char* buffer;
+ auto impl = StringImpl::create_uninitialized(length, buffer);
+
+ if constexpr (is_error_or)
+ TRY(fill_function(Bytes { buffer, length }));
+ else
+ fill_function(Bytes { buffer, length });
+ return impl;
+ }
+
  [[nodiscard]] static ByteString repeated(char, size_t count);
  [[nodiscard]] static ByteString repeated(StringView, size_t count);
 

diff --git a/Userland/Libraries/LibC/netdb.cpp b/Userland/Libraries/LibC/netdb.cpp
@@ -394,19 +394,21 @@ hostent* gethostbyaddr(void const* addr, socklen_t addr_size, int type)
  return nullptr;
  }
 
- char* buffer;
- auto string_impl = StringImpl::create_uninitialized(response_header.name_length, buffer);
+ ssize_t nreceived;
 
- if (auto nreceived = read(fd, buffer, response_header.name_length); nreceived < 0) {
+ gethostbyaddr_name_buffer = ByteString::create_and_overwrite(response_header.name_length, [&](Bytes bytes) {
+ nreceived = read(fd, bytes.data(), bytes.size());
+ });
+
+ if (nreceived < 0) {
  h_errno = TRY_AGAIN;
  return nullptr;
  } else if (static_cast<u32>(nreceived) != response_header.name_length) {
  h_errno = NO_RECOVERY;
  return nullptr;
  }
 
- gethostbyaddr_name_buffer = move(string_impl);
- __gethostbyaddr_buffer.h_name = buffer;
+ __gethostbyaddr_buffer.h_name = const_cast<char*>(gethostbyaddr_name_buffer.characters());
  __gethostbyaddr_alias_list_buffer[0] = nullptr;
  __gethostbyaddr_buffer.h_aliases = __gethostbyaddr_alias_list_buffer;
  __gethostbyaddr_buffer.h_addrtype = AF_INET;

diff --git a/Userland/Libraries/LibIPC/Decoder.cpp b/Userland/Libraries/LibIPC/Decoder.cpp
@@ -39,13 +39,10 @@ ErrorOr<ByteString> decode(Decoder& decoder)
  if (length == 0)
  return ByteString::empty();
 
- char* text_buffer = nullptr;
- auto text_impl = StringImpl::create_uninitialized(length, text_buffer);
-
- Bytes bytes { text_buffer, length };
- TRY(decoder.decode_into(bytes));
-
- return ByteString { *text_impl };
+ return ByteString::create_and_overwrite(length, [&](Bytes bytes) -> ErrorOr<void> {
+ TRY(decoder.decode_into(bytes));
+ return {};
+ });
 }
 
 template<>