[lldb] [Host] Remove TerminalStateSwitcher

[mgorny]

Summary

Remove TerminalStateSwitcher class. It is not used anywhere and its API
is really weird. This is the first step towards cleaning up Terminal.h.

[labath]

yay

[teemperor]

LGTM

lldb/include/lldb/Host/Terminal.h

protected:
   int m_tflags = -1; ///< Cached tflags information.
 #if LLDB_ENABLE_TERMIOS
   std::unique_ptr<struct termios>
       m_termios_up; ///< Cached terminal state information.
 #endif
   lldb::pid_t m_process_group = -1; ///< Cached process group information.
 };
 
-/// \class TerminalStateSwitcher Terminal.h "lldb/Host/Terminal.h"
-/// A TTY state switching class.
-///
-/// This class can be used to remember 2 TTY states for a given file
-/// descriptor and switch between the two states.
-class TerminalStateSwitcher {
-public:
-  /// Constructor
-  TerminalStateSwitcher();
-
-  /// Destructor
-  ~TerminalStateSwitcher();
-
-  /// Get the number of possible states to save.
-  ///
-  /// \return
-  ///     The number of states that this TTY switcher object contains.
-  uint32_t GetNumberOfStates() const;
-
-  /// Restore the TTY state for state at index \a idx.
-  ///
-  /// \return
-  ///     Returns \b true if the TTY state was successfully restored,
-  ///     \b false otherwise.
-  bool Restore(uint32_t idx) const;
-
-  /// Save the TTY state information for the state at index \a idx. The TTY
-  /// state is saved for the file descriptor \a fd and the process group
-  /// information will also be saved if requested by \a save_process_group.
-  ///
-  /// \param[in] idx
-  ///     The index into the state array where the state should be
-  ///     saved.
-  ///
-  /// \param[in] fd
-  ///     The file descriptor for which to save the settings.
-  ///
-  /// \param[in] save_process_group
-  ///     If \b true, save the process group information for the TTY.
-  ///
-  /// \return
-  ///     Returns \b true if the save was successful, \b false
-  ///     otherwise.
-  bool Save(uint32_t idx, int fd, bool save_process_group);
-
-protected:
-  // Member variables
-  mutable uint32_t m_currentState =
-      UINT32_MAX; ///< The currently active TTY state index.
-  TerminalState
-      m_ttystates[2]; ///< The array of TTY states that holds saved TTY info.
-};
-
 } // namespace lldb_private
 
 #endif // #if defined(__cplusplus)
 #endif // LLDB_HOST_TERMINAL_H

lldb/source/Host/common/Terminal.cpp

#else
   return false;
 #endif
 }
 
 // Returns true if m_process_group is valid
 bool TerminalState::ProcessGroupIsValid() const {
   return static_cast<int32_t>(m_process_group) != -1;
 }
-
-// Constructor
-TerminalStateSwitcher::TerminalStateSwitcher() = default;
-
-// Destructor
-TerminalStateSwitcher::~TerminalStateSwitcher() = default;
-
-// Returns the number of states that this switcher contains
-uint32_t TerminalStateSwitcher::GetNumberOfStates() const {
-  return llvm::array_lengthof(m_ttystates);
-}
-
-// Restore the state at index "idx".
-//
-// Returns true if the restore was successful, false otherwise.
-bool TerminalStateSwitcher::Restore(uint32_t idx) const {
-  const uint32_t num_states = GetNumberOfStates();
-  if (idx >= num_states)
-    return false;
-
-  // See if we already are in this state?
-  if (m_currentState < num_states && (idx == m_currentState) &&
-      m_ttystates[idx].IsValid())
-    return true;
-
-  // Set the state to match the index passed in and only update the current
-  // state if there are no errors.
-  if (m_ttystates[idx].Restore()) {
-    m_currentState = idx;
-    return true;
-  }
-
-  // We failed to set the state. The tty state was invalid or not initialized.
-  return false;
-}
-
-// Save the state at index "idx" for file descriptor "fd" and save the process
-// group if requested.
-//
-// Returns true if the restore was successful, false otherwise.
-bool TerminalStateSwitcher::Save(uint32_t idx, int fd,
-                                 bool save_process_group) {
-  const uint32_t num_states = GetNumberOfStates();
-  if (idx < num_states)
-    return m_ttystates[idx].Save(fd, save_process_group);
-  return false;
-}