feat(utils): add network error classification helper

Author: GaspardKirira

include/vix/utils/NetworkError.hpp

@@ -0,0 +1,136 @@
+/**
+ *
+ *  @file NetworkError.hpp
+ *  @author Gaspard Kirira
+ *
+ *  Copyright 2026, Gaspard Kirira. All rights reserved.
+ *  https://github.com/vixcpp/vix
+ *  Use of this source code is governed by a MIT license
+ *  that can be found in the License file.
+ *
+ *  Vix.cpp
+ */
+#ifndef VIX_UTILS_NETWORK_ERROR_HPP
+#define VIX_UTILS_NETWORK_ERROR_HPP
+
+#include <cctype>
+#include <cstddef>
+#include <cerrno>
+#include <string_view>
+#include <system_error>
+
+namespace vix::utils
+{
+  inline bool contains_token_icase(std::string_view text, std::string_view token)
+  {
+    if (token.empty())
+    {
+      return true;
+    }
+
+    if (token.size() > text.size())
+    {
+      return false;
+    }
+
+    const auto lower_char = [](unsigned char c) -> char
+    {
+      return static_cast<char>(std::tolower(c));
+    };
+
+    const char first = lower_char(static_cast<unsigned char>(token.front()));
+    const std::size_t last = text.size() - token.size();
+
+    for (std::size_t i = 0; i <= last; ++i)
+    {
+      if (lower_char(static_cast<unsigned char>(text[i])) != first)
+      {
+        continue;
+      }
+
+      std::size_t j = 1;
+
+      for (; j < token.size(); ++j)
+      {
+        if (lower_char(static_cast<unsigned char>(text[i + j])) !=
+            lower_char(static_cast<unsigned char>(token[j])))
+        {
+          break;
+        }
+      }
+
+      if (j == token.size())
+      {
+        return true;
+      }
+    }
+
+    return false;
+  }
+
+  inline bool is_normal_network_disconnect_message(std::string_view message) noexcept
+  {
+    return contains_token_icase(message, "broken pipe") ||
+           contains_token_icase(message, "connection reset") ||
+           contains_token_icase(message, "connection reset by peer") ||
+           contains_token_icase(message, "operation canceled") ||
+           contains_token_icase(message, "operation cancelled") ||
+           contains_token_icase(message, "canceled") ||
+           contains_token_icase(message, "cancelled") ||
+           contains_token_icase(message, "end of file") ||
+           contains_token_icase(message, "eof");
+  }
+
+  inline bool is_normal_network_disconnect(const std::system_error &e) noexcept
+  {
+    const auto code = e.code();
+
+    if (code == std::errc::operation_canceled ||
+        code == std::errc::broken_pipe ||
+        code == std::errc::connection_reset ||
+        code == std::errc::connection_aborted ||
+        code == std::errc::timed_out)
+    {
+      return true;
+    }
+
+#ifdef ECANCELED
+    if (code.value() == ECANCELED)
+    {
+      return true;
+    }
+#endif
+
+#ifdef EPIPE
+    if (code.value() == EPIPE)
+    {
+      return true;
+    }
+#endif
+
+#ifdef ECONNRESET
+    if (code.value() == ECONNRESET)
+    {
+      return true;
+    }
+#endif
+
+#ifdef ECONNABORTED
+    if (code.value() == ECONNABORTED)
+    {
+      return true;
+    }
+#endif
+
+#ifdef ETIMEDOUT
+    if (code.value() == ETIMEDOUT)
+    {
+      return true;
+    }
+#endif
+
+    return is_normal_network_disconnect_message(e.what());
+  }
+}
+
+#endif