# coding=utf-8 """ Imports the proper readline for the platform and provides utility functions for it """ import sys from enum import ( Enum, ) # Prefer statically linked gnureadline if available (for macOS compatibility due to issues with libedit) try: # noinspection PyPackageRequirements import gnureadline as readline # type: ignore[import] except ImportError: # Try to import readline, but allow failure for convenience in Windows unit testing # Note: If this actually fails, you should install readline on Linux or Mac or pyreadline on Windows try: # noinspection PyUnresolvedReferences import readline # type: ignore[no-redef] except ImportError: # pragma: no cover pass class RlType(Enum): """Readline library types we recognize""" GNU = 1 PYREADLINE = 2 NONE = 3 # Check what implementation of readline we are using rl_type = RlType.NONE # Tells if the terminal we are running in supports vt100 control characters vt100_support = False # Explanation for why readline wasn't loaded _rl_warn_reason = '' # The order of this check matters since importing pyreadline/pyreadline3 will also show readline in the modules list if 'pyreadline' in sys.modules or 'pyreadline3' in sys.modules: rl_type = RlType.PYREADLINE import atexit from ctypes import ( byref, ) from ctypes.wintypes import ( DWORD, HANDLE, ) # Check if we are running in a terminal if sys.stdout.isatty(): # pragma: no cover # noinspection PyPep8Naming,PyUnresolvedReferences def enable_win_vt100(handle: HANDLE) -> bool: """ Enables VT100 character sequences in a Windows console This only works on Windows 10 and up :param handle: the handle on which to enable vt100 :return: True if vt100 characters are enabled for the handle """ ENABLE_VIRTUAL_TERMINAL_PROCESSING = 0x0004 # Get the current mode for this handle in the console cur_mode = DWORD(0) readline.rl.console.GetConsoleMode(handle, byref(cur_mode)) retVal = False # Check if ENABLE_VIRTUAL_TERMINAL_PROCESSING is already enabled if (cur_mode.value & ENABLE_VIRTUAL_TERMINAL_PROCESSING) != 0: retVal = True elif readline.rl.console.SetConsoleMode(handle, cur_mode.value | ENABLE_VIRTUAL_TERMINAL_PROCESSING): # Restore the original mode when we exit atexit.register(readline.rl.console.SetConsoleMode, handle, cur_mode) retVal = True return retVal # Enable VT100 sequences for stdout and stderr STD_OUT_HANDLE = -11 STD_ERROR_HANDLE = -12 # noinspection PyUnresolvedReferences vt100_stdout_support = enable_win_vt100(readline.rl.console.GetStdHandle(STD_OUT_HANDLE)) # noinspection PyUnresolvedReferences vt100_stderr_support = enable_win_vt100(readline.rl.console.GetStdHandle(STD_ERROR_HANDLE)) vt100_support = vt100_stdout_support and vt100_stderr_support ############################################################################################################ # pyreadline is incomplete in terms of the Python readline API. Add the missing functions we need. ############################################################################################################ # readline.redisplay() try: getattr(readline, 'redisplay') except AttributeError: # noinspection PyProtectedMember,PyUnresolvedReferences readline.redisplay = readline.rl.mode._update_line # readline.remove_history_item() try: getattr(readline, 'remove_history_item') except AttributeError: # noinspection PyProtectedMember,PyUnresolvedReferences def pyreadline_remove_history_item(pos: int) -> None: """ An implementation of remove_history_item() for pyreadline :param pos: The 0-based position in history to remove """ # Save of the current location of the history cursor saved_cursor = readline.rl.mode._history.history_cursor # Delete the history item del readline.rl.mode._history.history[pos] # Update the cursor if needed if saved_cursor > pos: readline.rl.mode._history.history_cursor -= 1 readline.remove_history_item = pyreadline_remove_history_item elif 'gnureadline' in sys.modules or 'readline' in sys.modules: # We don't support libedit if 'libedit' not in readline.__doc__: try: # Load the readline lib so we can access members of it import ctypes readline_lib = ctypes.CDLL(readline.__file__) except (AttributeError, OSError): # pragma: no cover _rl_warn_reason = ( "this application is running in a non-standard Python environment in\n" "which GNU readline is not loaded dynamically from a shared library file." ) else: rl_type = RlType.GNU vt100_support = sys.stdout.isatty() # Check if readline was loaded if rl_type == RlType.NONE: # pragma: no cover if not _rl_warn_reason: _rl_warn_reason = ( "no supported version of readline was found. To resolve this, install\n" "pyreadline on Windows or gnureadline on Mac." ) rl_warning = "Readline features including tab completion have been disabled because\n" + _rl_warn_reason + '\n\n' else: rl_warning = '' # noinspection PyProtectedMember,PyUnresolvedReferences def rl_force_redisplay() -> None: # pragma: no cover """ Causes readline to display the prompt and input text wherever the cursor is and start reading input from this location. This is the proper way to restore the input line after printing to the screen """ if not sys.stdout.isatty(): return if rl_type == RlType.GNU: readline_lib.rl_forced_update_display() # After manually updating the display, readline asks that rl_display_fixed be set to 1 for efficiency display_fixed = ctypes.c_int.in_dll(readline_lib, "rl_display_fixed") display_fixed.value = 1 elif rl_type == RlType.PYREADLINE: # Call _print_prompt() first to set the new location of the prompt readline.rl.mode._print_prompt() readline.rl.mode._update_line() # noinspection PyProtectedMember, PyUnresolvedReferences def rl_get_point() -> int: # pragma: no cover """ Returns the offset of the current cursor position in rl_line_buffer """ if rl_type == RlType.GNU: return ctypes.c_int.in_dll(readline_lib, "rl_point").value elif rl_type == RlType.PYREADLINE: return int(readline.rl.mode.l_buffer.point) else: return 0 # noinspection PyProtectedMember, PyUnresolvedReferences def rl_set_prompt(prompt: str) -> None: # pragma: no cover """ Sets readline's prompt :param prompt: the new prompt value """ safe_prompt = rl_make_safe_prompt(prompt) if rl_type == RlType.GNU: encoded_prompt = bytes(safe_prompt, encoding='utf-8') readline_lib.rl_set_prompt(encoded_prompt) elif rl_type == RlType.PYREADLINE: readline.rl._set_prompt(safe_prompt) def rl_make_safe_prompt(prompt: str) -> str: # pragma: no cover """Overcome bug in GNU Readline in relation to calculation of prompt length in presence of ANSI escape codes :param prompt: original prompt :return: prompt safe to pass to GNU Readline """ if rl_type == RlType.GNU: # start code to tell GNU Readline about beginning of invisible characters start = "\x01" # end code to tell GNU Readline about end of invisible characters end = "\x02" escaped = False result = "" for c in prompt: if c == "\x1b" and not escaped: result += start + c escaped = True elif c.isalpha() and escaped: result += c + end escaped = False else: result += c return result else: return prompt