efro.terminal

  1# Released under the MIT License. See LICENSE for details.
  2#
  3"""Functionality related to terminal IO."""
  4from __future__ import annotations
  5
  6import sys
  7import os
  8from enum import Enum, unique
  9from typing import TYPE_CHECKING
 10
 11if TYPE_CHECKING:
 12    from typing import Any, ClassVar
 13
 14
 15@unique
 16class TerminalColor(Enum):
 17    """Color codes for printing to terminals.
 18
 19    Generally the Clr class should be used when incorporating color into
 20    terminal output, as it handles non-color-supporting terminals/etc.
 21    """
 22
 23    # Styles
 24    RESET = '\033[0m'
 25    BOLD = '\033[1m'
 26    UNDERLINE = '\033[4m'
 27    INVERSE = '\033[7m'
 28
 29    # Normal foreground colors
 30    BLACK = '\033[30m'
 31    RED = '\033[31m'
 32    GREEN = '\033[32m'
 33    YELLOW = '\033[33m'
 34    BLUE = '\033[34m'
 35    MAGENTA = '\033[35m'
 36    CYAN = '\033[36m'
 37    WHITE = '\033[37m'
 38
 39    # Normal background colors.
 40    BG_BLACK = '\033[40m'
 41    BG_RED = '\033[41m'
 42    BG_GREEN = '\033[42m'
 43    BG_YELLOW = '\033[43m'
 44    BG_BLUE = '\033[44m'
 45    BG_MAGENTA = '\033[45m'
 46    BG_CYAN = '\033[46m'
 47    BG_WHITE = '\033[47m'
 48
 49    # Strong foreground colors
 50    STRONG_BLACK = '\033[90m'
 51    STRONG_RED = '\033[91m'
 52    STRONG_GREEN = '\033[92m'
 53    STRONG_YELLOW = '\033[93m'
 54    STRONG_BLUE = '\033[94m'
 55    STRONG_MAGENTA = '\033[95m'
 56    STRONG_CYAN = '\033[96m'
 57    STRONG_WHITE = '\033[97m'
 58
 59    # Strong background colors.
 60    STRONG_BG_BLACK = '\033[100m'
 61    STRONG_BG_RED = '\033[101m'
 62    STRONG_BG_GREEN = '\033[102m'
 63    STRONG_BG_YELLOW = '\033[103m'
 64    STRONG_BG_BLUE = '\033[104m'
 65    STRONG_BG_MAGENTA = '\033[105m'
 66    STRONG_BG_CYAN = '\033[106m'
 67    STRONG_BG_WHITE = '\033[107m'
 68
 69
 70def _default_color_enabled() -> bool:
 71    """Return whether we enable ANSI color codes by default."""
 72    import platform
 73
 74    # If our stdout is not attached to a terminal, go with no-color.
 75    if not sys.__stdout__.isatty():
 76        return False
 77
 78    termenv = os.environ.get('TERM')
 79
 80    # If TERM is unset, don't attempt color (this is currently the case
 81    # in xcode).
 82    if termenv is None:
 83        return False
 84
 85    # A common way to say the terminal can't do fancy stuff like color.
 86    if termenv == 'dumb':
 87        return False
 88
 89    # On windows, try to enable ANSI color mode.
 90    if platform.system() == 'Windows':
 91        return _windows_enable_color()
 92
 93    # We seem to be a terminal with color support; let's do it!
 94    return True
 95
 96
 97# noinspection PyPep8Naming
 98def _windows_enable_color() -> bool:
 99    """Attempt to enable ANSI color on windows terminal; return success."""
100    # pylint: disable=invalid-name, import-error, undefined-variable
101    # Pulled from: https://bugs.python.org/issue30075
102    import msvcrt
103    import ctypes
104    from ctypes import wintypes
105
106    kernel32 = ctypes.WinDLL('kernel32', use_last_error=True)  # type: ignore
107
108    ERROR_INVALID_PARAMETER = 0x0057
109    ENABLE_VIRTUAL_TERMINAL_PROCESSING = 0x0004
110
111    def _check_bool(result: Any, _func: Any, args: Any) -> Any:
112        if not result:
113            raise ctypes.WinError(ctypes.get_last_error())  # type: ignore
114        return args
115
116    LPDWORD = ctypes.POINTER(wintypes.DWORD)
117    kernel32.GetConsoleMode.errcheck = _check_bool
118    kernel32.GetConsoleMode.argtypes = (wintypes.HANDLE, LPDWORD)
119    kernel32.SetConsoleMode.errcheck = _check_bool
120    kernel32.SetConsoleMode.argtypes = (wintypes.HANDLE, wintypes.DWORD)
121
122    def set_conout_mode(new_mode: int, mask: int = 0xFFFFFFFF) -> int:
123        # don't assume StandardOutput is a console.
124        # open CONOUT$ instead
125        fdout = os.open('CONOUT$', os.O_RDWR)
126        try:
127            hout = msvcrt.get_osfhandle(fdout)  # type: ignore
128            # pylint: disable=useless-suppression
129            # pylint: disable=no-value-for-parameter
130            old_mode = wintypes.DWORD()
131            # pylint: enable=useless-suppression
132            kernel32.GetConsoleMode(hout, ctypes.byref(old_mode))
133            mode = (new_mode & mask) | (old_mode.value & ~mask)
134            kernel32.SetConsoleMode(hout, mode)
135            return old_mode.value
136        finally:
137            os.close(fdout)
138
139    def enable_vt_mode() -> int:
140        mode = mask = ENABLE_VIRTUAL_TERMINAL_PROCESSING
141        try:
142            return set_conout_mode(mode, mask)
143        except WindowsError as exc:  # type: ignore
144            if exc.winerror == ERROR_INVALID_PARAMETER:
145                raise NotImplementedError from exc
146            raise
147
148    try:
149        enable_vt_mode()
150        return True
151    except NotImplementedError:
152        return False
153
154
155class ClrBase:
156    """Base class for color convenience class."""
157
158    RST: ClassVar[str]
159    BLD: ClassVar[str]
160    UND: ClassVar[str]
161    INV: ClassVar[str]
162
163    # Normal foreground colors
164    BLK: ClassVar[str]
165    RED: ClassVar[str]
166    GRN: ClassVar[str]
167    YLW: ClassVar[str]
168    BLU: ClassVar[str]
169    MAG: ClassVar[str]
170    CYN: ClassVar[str]
171    WHT: ClassVar[str]
172
173    # Normal background colors.
174    BBLK: ClassVar[str]
175    BRED: ClassVar[str]
176    BGRN: ClassVar[str]
177    BYLW: ClassVar[str]
178    BBLU: ClassVar[str]
179    BMAG: ClassVar[str]
180    BCYN: ClassVar[str]
181    BWHT: ClassVar[str]
182
183    # Strong foreground colors
184    SBLK: ClassVar[str]
185    SRED: ClassVar[str]
186    SGRN: ClassVar[str]
187    SYLW: ClassVar[str]
188    SBLU: ClassVar[str]
189    SMAG: ClassVar[str]
190    SCYN: ClassVar[str]
191    SWHT: ClassVar[str]
192
193    # Strong background colors.
194    SBBLK: ClassVar[str]
195    SBRED: ClassVar[str]
196    SBGRN: ClassVar[str]
197    SBYLW: ClassVar[str]
198    SBBLU: ClassVar[str]
199    SBMAG: ClassVar[str]
200    SBCYN: ClassVar[str]
201    SBWHT: ClassVar[str]
202
203
204class ClrAlways(ClrBase):
205    """Convenience class for color terminal output.
206
207    This version has colors always enabled. Generally you should use Clr which
208    points to the correct enabled/disabled class depending on the environment.
209    """
210
211    color_enabled = True
212
213    # Styles
214    RST = TerminalColor.RESET.value
215    BLD = TerminalColor.BOLD.value
216    UND = TerminalColor.UNDERLINE.value
217    INV = TerminalColor.INVERSE.value
218
219    # Normal foreground colors
220    BLK = TerminalColor.BLACK.value
221    RED = TerminalColor.RED.value
222    GRN = TerminalColor.GREEN.value
223    YLW = TerminalColor.YELLOW.value
224    BLU = TerminalColor.BLUE.value
225    MAG = TerminalColor.MAGENTA.value
226    CYN = TerminalColor.CYAN.value
227    WHT = TerminalColor.WHITE.value
228
229    # Normal background colors.
230    BBLK = TerminalColor.BG_BLACK.value
231    BRED = TerminalColor.BG_RED.value
232    BGRN = TerminalColor.BG_GREEN.value
233    BYLW = TerminalColor.BG_YELLOW.value
234    BBLU = TerminalColor.BG_BLUE.value
235    BMAG = TerminalColor.BG_MAGENTA.value
236    BCYN = TerminalColor.BG_CYAN.value
237    BWHT = TerminalColor.BG_WHITE.value
238
239    # Strong foreground colors
240    SBLK = TerminalColor.STRONG_BLACK.value
241    SRED = TerminalColor.STRONG_RED.value
242    SGRN = TerminalColor.STRONG_GREEN.value
243    SYLW = TerminalColor.STRONG_YELLOW.value
244    SBLU = TerminalColor.STRONG_BLUE.value
245    SMAG = TerminalColor.STRONG_MAGENTA.value
246    SCYN = TerminalColor.STRONG_CYAN.value
247    SWHT = TerminalColor.STRONG_WHITE.value
248
249    # Strong background colors.
250    SBBLK = TerminalColor.STRONG_BG_BLACK.value
251    SBRED = TerminalColor.STRONG_BG_RED.value
252    SBGRN = TerminalColor.STRONG_BG_GREEN.value
253    SBYLW = TerminalColor.STRONG_BG_YELLOW.value
254    SBBLU = TerminalColor.STRONG_BG_BLUE.value
255    SBMAG = TerminalColor.STRONG_BG_MAGENTA.value
256    SBCYN = TerminalColor.STRONG_BG_CYAN.value
257    SBWHT = TerminalColor.STRONG_BG_WHITE.value
258
259
260class ClrNever(ClrBase):
261    """Convenience class for color terminal output.
262
263    This version has colors disabled. Generally you should use Clr which
264    points to the correct enabled/disabled class depending on the environment.
265    """
266
267    color_enabled = False
268
269    # Styles
270    RST = ''
271    BLD = ''
272    UND = ''
273    INV = ''
274
275    # Normal foreground colors
276    BLK = ''
277    RED = ''
278    GRN = ''
279    YLW = ''
280    BLU = ''
281    MAG = ''
282    CYN = ''
283    WHT = ''
284
285    # Normal background colors.
286    BBLK = ''
287    BRED = ''
288    BGRN = ''
289    BYLW = ''
290    BBLU = ''
291    BMAG = ''
292    BCYN = ''
293    BWHT = ''
294
295    # Strong foreground colors
296    SBLK = ''
297    SRED = ''
298    SGRN = ''
299    SYLW = ''
300    SBLU = ''
301    SMAG = ''
302    SCYN = ''
303    SWHT = ''
304
305    # Strong background colors.
306    SBBLK = ''
307    SBRED = ''
308    SBGRN = ''
309    SBYLW = ''
310    SBBLU = ''
311    SBMAG = ''
312    SBCYN = ''
313    SBWHT = ''
314
315
316_envval = os.environ.get('EFRO_TERMCOLORS')
317color_enabled: bool = (
318    True
319    if _envval == '1'
320    else False if _envval == '0' else _default_color_enabled()
321)
322Clr: type[ClrBase] = ClrAlways if color_enabled else ClrNever