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 we're not attached to a terminal, go with no-color.
 75    if not sys.__stdout__.isatty():
 76        return False
 77
 78    # Another common way to say the terminal can't do fancy stuff like color:
 79    if os.environ.get('TERM') == 'dumb':
 80        return False
 81
 82    # On windows, try to enable ANSI color mode.
 83    if platform.system() == 'Windows':
 84        return _windows_enable_color()
 85
 86    # We seem to be a terminal with color support; let's do it!
 87    return True
 88
 89
 90# noinspection PyPep8Naming
 91def _windows_enable_color() -> bool:
 92    """Attempt to enable ANSI color on windows terminal; return success."""
 93    # pylint: disable=invalid-name, import-error, undefined-variable
 94    # Pulled from: https://bugs.python.org/issue30075
 95    import msvcrt
 96    import ctypes
 97    from ctypes import wintypes
 98
 99    kernel32 = ctypes.WinDLL('kernel32', use_last_error=True)  # type: ignore
100
101    ERROR_INVALID_PARAMETER = 0x0057
102    ENABLE_VIRTUAL_TERMINAL_PROCESSING = 0x0004
103
104    def _check_bool(result: Any, _func: Any, args: Any) -> Any:
105        if not result:
106            raise ctypes.WinError(ctypes.get_last_error())  # type: ignore
107        return args
108
109    LPDWORD = ctypes.POINTER(wintypes.DWORD)
110    kernel32.GetConsoleMode.errcheck = _check_bool
111    kernel32.GetConsoleMode.argtypes = (wintypes.HANDLE, LPDWORD)
112    kernel32.SetConsoleMode.errcheck = _check_bool
113    kernel32.SetConsoleMode.argtypes = (wintypes.HANDLE, wintypes.DWORD)
114
115    def set_conout_mode(new_mode: int, mask: int = 0xFFFFFFFF) -> int:
116        # don't assume StandardOutput is a console.
117        # open CONOUT$ instead
118        fdout = os.open('CONOUT$', os.O_RDWR)
119        try:
120            hout = msvcrt.get_osfhandle(fdout)  # type: ignore
121            # pylint: disable=useless-suppression
122            # pylint: disable=no-value-for-parameter
123            old_mode = wintypes.DWORD()
124            # pylint: enable=useless-suppression
125            kernel32.GetConsoleMode(hout, ctypes.byref(old_mode))
126            mode = (new_mode & mask) | (old_mode.value & ~mask)
127            kernel32.SetConsoleMode(hout, mode)
128            return old_mode.value
129        finally:
130            os.close(fdout)
131
132    def enable_vt_mode() -> int:
133        mode = mask = ENABLE_VIRTUAL_TERMINAL_PROCESSING
134        try:
135            return set_conout_mode(mode, mask)
136        except WindowsError as exc:  # type: ignore
137            if exc.winerror == ERROR_INVALID_PARAMETER:
138                raise NotImplementedError from exc
139            raise
140
141    try:
142        enable_vt_mode()
143        return True
144    except NotImplementedError:
145        return False
146
147
148class ClrBase:
149    """Base class for color convenience class."""
150
151    RST: ClassVar[str]
152    BLD: ClassVar[str]
153    UND: ClassVar[str]
154    INV: ClassVar[str]
155
156    # Normal foreground colors
157    BLK: ClassVar[str]
158    RED: ClassVar[str]
159    GRN: ClassVar[str]
160    YLW: ClassVar[str]
161    BLU: ClassVar[str]
162    MAG: ClassVar[str]
163    CYN: ClassVar[str]
164    WHT: ClassVar[str]
165
166    # Normal background colors.
167    BBLK: ClassVar[str]
168    BRED: ClassVar[str]
169    BGRN: ClassVar[str]
170    BYLW: ClassVar[str]
171    BBLU: ClassVar[str]
172    BMAG: ClassVar[str]
173    BCYN: ClassVar[str]
174    BWHT: ClassVar[str]
175
176    # Strong foreground colors
177    SBLK: ClassVar[str]
178    SRED: ClassVar[str]
179    SGRN: ClassVar[str]
180    SYLW: ClassVar[str]
181    SBLU: ClassVar[str]
182    SMAG: ClassVar[str]
183    SCYN: ClassVar[str]
184    SWHT: ClassVar[str]
185
186    # Strong background colors.
187    SBBLK: ClassVar[str]
188    SBRED: ClassVar[str]
189    SBGRN: ClassVar[str]
190    SBYLW: ClassVar[str]
191    SBBLU: ClassVar[str]
192    SBMAG: ClassVar[str]
193    SBCYN: ClassVar[str]
194    SBWHT: ClassVar[str]
195
196
197class ClrAlways(ClrBase):
198    """Convenience class for color terminal output.
199
200    This version has colors always enabled. Generally you should use Clr which
201    points to the correct enabled/disabled class depending on the environment.
202    """
203
204    color_enabled = True
205
206    # Styles
207    RST = TerminalColor.RESET.value
208    BLD = TerminalColor.BOLD.value
209    UND = TerminalColor.UNDERLINE.value
210    INV = TerminalColor.INVERSE.value
211
212    # Normal foreground colors
213    BLK = TerminalColor.BLACK.value
214    RED = TerminalColor.RED.value
215    GRN = TerminalColor.GREEN.value
216    YLW = TerminalColor.YELLOW.value
217    BLU = TerminalColor.BLUE.value
218    MAG = TerminalColor.MAGENTA.value
219    CYN = TerminalColor.CYAN.value
220    WHT = TerminalColor.WHITE.value
221
222    # Normal background colors.
223    BBLK = TerminalColor.BG_BLACK.value
224    BRED = TerminalColor.BG_RED.value
225    BGRN = TerminalColor.BG_GREEN.value
226    BYLW = TerminalColor.BG_YELLOW.value
227    BBLU = TerminalColor.BG_BLUE.value
228    BMAG = TerminalColor.BG_MAGENTA.value
229    BCYN = TerminalColor.BG_CYAN.value
230    BWHT = TerminalColor.BG_WHITE.value
231
232    # Strong foreground colors
233    SBLK = TerminalColor.STRONG_BLACK.value
234    SRED = TerminalColor.STRONG_RED.value
235    SGRN = TerminalColor.STRONG_GREEN.value
236    SYLW = TerminalColor.STRONG_YELLOW.value
237    SBLU = TerminalColor.STRONG_BLUE.value
238    SMAG = TerminalColor.STRONG_MAGENTA.value
239    SCYN = TerminalColor.STRONG_CYAN.value
240    SWHT = TerminalColor.STRONG_WHITE.value
241
242    # Strong background colors.
243    SBBLK = TerminalColor.STRONG_BG_BLACK.value
244    SBRED = TerminalColor.STRONG_BG_RED.value
245    SBGRN = TerminalColor.STRONG_BG_GREEN.value
246    SBYLW = TerminalColor.STRONG_BG_YELLOW.value
247    SBBLU = TerminalColor.STRONG_BG_BLUE.value
248    SBMAG = TerminalColor.STRONG_BG_MAGENTA.value
249    SBCYN = TerminalColor.STRONG_BG_CYAN.value
250    SBWHT = TerminalColor.STRONG_BG_WHITE.value
251
252
253class ClrNever(ClrBase):
254    """Convenience class for color terminal output.
255
256    This version has colors disabled. Generally you should use Clr which
257    points to the correct enabled/disabled class depending on the environment.
258    """
259
260    color_enabled = False
261
262    # Styles
263    RST = ''
264    BLD = ''
265    UND = ''
266    INV = ''
267
268    # Normal foreground colors
269    BLK = ''
270    RED = ''
271    GRN = ''
272    YLW = ''
273    BLU = ''
274    MAG = ''
275    CYN = ''
276    WHT = ''
277
278    # Normal background colors.
279    BBLK = ''
280    BRED = ''
281    BGRN = ''
282    BYLW = ''
283    BBLU = ''
284    BMAG = ''
285    BCYN = ''
286    BWHT = ''
287
288    # Strong foreground colors
289    SBLK = ''
290    SRED = ''
291    SGRN = ''
292    SYLW = ''
293    SBLU = ''
294    SMAG = ''
295    SCYN = ''
296    SWHT = ''
297
298    # Strong background colors.
299    SBBLK = ''
300    SBRED = ''
301    SBGRN = ''
302    SBYLW = ''
303    SBBLU = ''
304    SBMAG = ''
305    SBCYN = ''
306    SBWHT = ''
307
308
309_envval = os.environ.get('EFRO_TERMCOLORS')
310color_enabled: bool = (
311    True
312    if _envval == '1'
313    else False
314    if _envval == '0'
315    else _default_color_enabled()
316)
317Clr: type[ClrBase] = ClrAlways if color_enabled else ClrNever