fixup! fixup! [lldb] improve the heuristics for checking if a terminal supports Unicode

Author: charles-zablit

lldb/include/lldb/Host/Terminal.h

@@ -68,6 +68,18 @@ class Terminal {
 
   llvm::Error SetHardwareFlowControl(bool enabled);
 
+  /// Returns whether or not the current terminal supports Unicode rendering.
+  ///
+  /// The value is cached after the first computation.
+  ///
+  /// On POSIX systems, we check if the LANG environment variable contains the
+  /// substring "UTF-8", case insensitive.
+  ///
+  /// On Windows, we always return true since we use the `WriteConsoleW` API
+  /// internally. Note that the default Windows codepage (437) does not support
+  /// all Unicode characters. This function does not check the codepage.
+  static bool SupportsUnicode();
+
 protected:
   struct Data;
 
@@ -169,18 +181,6 @@ class TerminalState {
   lldb::pid_t m_process_group = -1;       ///< Cached process group information.
 };
 
-/// Returns whether or not the current terminal supports Unicode rendering.
-///
-/// The value is cached after the first computation.
-///
-/// On POSIX systems, we check if the LANG environment variable contains the
-/// substring "UTF-8", case insensitive.
-///
-/// On Windows, we always return true since we use the `WriteConsoleW` API
-/// internally. Note that the default Windows codepage (437) does not support
-/// all Unicode characters. This function does not check the codepage.
-bool TerminalSupportsUnicode();
-
 } // namespace lldb_private
 
 #endif // LLDB_HOST_TERMINAL_H

lldb/source/Host/common/Terminal.cpp

@@ -400,6 +400,21 @@ llvm::Error Terminal::SetHardwareFlowControl(bool enabled) {
 #endif // LLDB_ENABLE_TERMIOS
 }
 
+bool Terminal::SupportsUnicode() {
+  static std::optional<bool> result;
+  if (result)
+    return result.value();
+#ifdef _WIN32
+  return true;
+#else
+  const char *lang_var = std::getenv("LANG");
+  if (!lang_var)
+    return false;
+  result = llvm::StringRef(lang_var).lower().find("utf-8") != std::string::npos;
+#endif
+  return result.value();
+}
+
 TerminalState::TerminalState(Terminal term, bool save_process_group)
     : m_tty(term) {
   Save(term, save_process_group);
@@ -472,18 +487,3 @@ bool TerminalState::TTYStateIsValid() const { return bool(m_data); }
 bool TerminalState::ProcessGroupIsValid() const {
   return static_cast<int32_t>(m_process_group) != -1;
 }
-
-bool lldb_private::TerminalSupportsUnicode() {
-  static std::optional<bool> result;
-  if (result)
-    return result.value();
-#ifdef _WIN32
-  return true;
-#else
-  const char *lang_var = std::getenv("LANG");
-  if (!lang_var)
-    return false;
-  result = llvm::StringRef(lang_var).lower().find("utf-8") != std::string::npos;
-#endif
-  return result.value();
-}