Use a nicer decorator for functions that only need to be run once

kittens/diff/render.py

@@ -3,16 +3,17 @@
 # License: GPL v3 Copyright: 2018, Kovid Goyal <kovid at kovidgoyal.net>
 
 import warnings
-from functools import lru_cache
 from gettext import gettext as _
 from itertools import repeat, zip_longest
 from math import ceil
 from typing import Callable, Dict, Generator, Iterable, List, Optional, Tuple
 
-from kitty.fast_data_types import truncate_point_for_length, wcswidth
 from kitty.cli_stub import DiffCLIOptions
+from kitty.fast_data_types import truncate_point_for_length, wcswidth
+from kitty.types import run_once
 from kitty.utils import ScreenSize
 
+from ..tui.images import ImageManager, can_display_images
 from .collect import (
     Collection, Segment, data_for_path, highlights_for_path, is_image,
     lines_for_path, path_name_map, sanitize
@@ -20,14 +21,13 @@ from .collect import (
 from .config import formats
 from .diff_speedup import split_with_highlights as _split_with_highlights
 from .patch import Chunk, Hunk, Patch
-from ..tui.images import ImageManager, can_display_images
 
 
 class ImageSupportWarning(Warning):
     pass
 
 
-@lru_cache(maxsize=2)
+@run_once
 def images_supported() -> bool:
     ans = can_display_images()
     if not ans:

kittens/icat/main.py

@@ -10,7 +10,6 @@ import socket
 import sys
 import zlib
 from base64 import standard_b64encode
-from functools import lru_cache
 from math import ceil
 from tempfile import NamedTemporaryFile
 from typing import (
@@ -21,6 +20,7 @@ from kitty.cli import parse_args
 from kitty.cli_stub import IcatCLIOptions
 from kitty.constants import appname
 from kitty.guess_mime_type import guess_type
+from kitty.types import run_once
 from kitty.typing import GRT_f, GRT_t
 from kitty.utils import (
     TTYIO, ScreenSize, ScreenSizeGetter, fit_image, screen_size_function
@@ -142,7 +142,7 @@ def get_screen_size() -> ScreenSize:
     return screen_size()
 
 
-@lru_cache(maxsize=2)
+@run_once
 def options_spec() -> str:
     return OPTIONS.format(appname='{}-icat'.format(appname))
 

kittens/runner.py

@@ -6,9 +6,11 @@
 import importlib
 import os
 import sys
-from functools import lru_cache, partial
+from functools import partial
 from typing import Any, Dict, FrozenSet, List
 
+from kitty.types import run_once
+
 aliases = {'url_hints': 'hints'}
 
 
@@ -57,8 +59,9 @@ def create_kitten_handler(kitten: str, orig_args: List[str]) -> Any:
 
 
 def set_debug(kitten: str) -> None:
-    from kittens.tui.loop import debug
     import builtins
+
+    from kittens.tui.loop import debug
     setattr(builtins, 'debug', debug)
 
 
@@ -118,7 +121,7 @@ def run_kitten(kitten: str, run_name: str = '__main__') -> None:
     m['main'](sys.argv)
 
 
-@lru_cache(maxsize=2)
+@run_once
 def all_kitten_names() -> FrozenSet[str]:
     n = []
     import glob

kitty/complete.py

@@ -5,7 +5,6 @@
 import os
 import shlex
 import sys
-from functools import lru_cache
 from typing import (
     Any, Callable, Dict, Iterable, List, Optional, Sequence, Set, Tuple
 )
@@ -17,6 +16,7 @@ from .cli import (
 )
 from .rc.base import all_command_names, command_for_name
 from .shell import options_for_cmd
+from .types import run_once
 
 '''
 To add completion for a new shell, you need to:
@@ -75,7 +75,7 @@ class Completions:
         self.delegate: Delegate = Delegate()
 
 
-@lru_cache(maxsize=2)
+@run_once
 def remote_control_command_names() -> Tuple[str, ...]:
     return tuple(sorted(x.replace('_', '-') for x in all_command_names()))
 

kitty/constants.py

@@ -7,10 +7,10 @@ import os
 import pwd
 import sys
 from contextlib import suppress
-from functools import lru_cache
 from typing import NamedTuple, Optional, Set
 
 from .options_stub import Options
+from .types import run_once
 
 
 class Version(NamedTuple):
@@ -27,7 +27,7 @@ is_macos: bool = 'darwin' in _plat
 base = os.path.dirname(os.path.abspath(__file__))
 
 
-@lru_cache(maxsize=2)
+@run_once
 def kitty_exe() -> str:
     rpath = sys._xoptions.get('bundle_exe_dir')
     if not rpath:
@@ -93,11 +93,8 @@ del _get_config_dir
 defconf = os.path.join(config_dir, 'kitty.conf')
 
 
-@lru_cache(maxsize=2)
+@run_once
 def cache_dir() -> str:
-    override: Optional[str] = getattr(cache_dir, 'override_dir', None)
-    if override:
-        return override
     if 'KITTY_CACHE_DIRECTORY' in os.environ:
         candidate = os.path.abspath(os.environ['KITTY_CACHE_DIRECTORY'])
     elif is_macos:

kitty/launch.py

@@ -3,7 +3,6 @@
 # License: GPLv3 Copyright: 2019, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from functools import lru_cache
 from typing import Any, Dict, List, NamedTuple, Optional, Sequence
 
 from .boss import Boss
@@ -13,6 +12,7 @@ from .cli_stub import LaunchCLIOptions
 from .constants import resolve_custom_file
 from .fast_data_types import patch_color_profiles, set_clipboard_string
 from .tabs import Tab
+from .types import run_once
 from .utils import find_exe, read_shell_environment, set_primary_selection
 from .window import Watchers, Window
 
@@ -27,7 +27,7 @@ class LaunchSpec(NamedTuple):
     args: List[str]
 
 
-@lru_cache(maxsize=2)
+@run_once
 def options_spec() -> str:
     return '''
 --window-title --title

kitty/open_actions.py

@@ -6,7 +6,6 @@
 import os
 import posixpath
 from contextlib import suppress
-from functools import lru_cache
 from typing import (
     Any, Generator, Iterable, List, NamedTuple, Optional, Tuple, cast
 )
@@ -15,9 +14,10 @@ from urllib.parse import ParseResult, unquote, urlparse
 from .conf.utils import to_cmdline
 from .config import KeyAction, parse_key_action
 from .constants import config_dir
+from .guess_mime_type import guess_type
+from .types import run_once
 from .typing import MatchType
 from .utils import expandvars, log_error
-from .guess_mime_type import guess_type
 
 
 class MatchCriteria(NamedTuple):
@@ -175,7 +175,7 @@ def actions_for_url_from_list(url: str, actions: Iterable[OpenAction]) -> Genera
             return
 
 
-@lru_cache(maxsize=2)
+@run_once
 def load_open_actions() -> Tuple[OpenAction, ...]:
     try:
         f = open(os.path.join(config_dir, 'open-actions.conf'))

kitty/shell.py

@@ -21,9 +21,10 @@ from .rc.base import (
     RemoteCommand, all_command_names, command_for_name,
     display_subcommand_help, parse_subcommand_cli
 )
+from .types import run_once
 
 
-@lru_cache(maxsize=2)
+@run_once
 def match_commands() -> Tuple[str, ...]:
     all_commands = tuple(sorted(x.replace('_', '-') for x in all_command_names()))
     return tuple(sorted(all_commands + ('exit', 'help', 'quit')))

kitty/types.py

@@ -2,7 +2,10 @@
 # vim:fileencoding=utf-8
 # License: GPLv3 Copyright: 2021, Kovid Goyal <kovid at kovidgoyal.net>
 
-from typing import NamedTuple, Union
+from functools import update_wrapper
+from typing import TYPE_CHECKING, Callable, Generic, NamedTuple, TypeVar, Union
+
+_T = TypeVar('_T')
 
 
 class ParsedShortcut(NamedTuple):
@@ -50,3 +53,36 @@ class SingleKey(NamedTuple):
 
 
 ConvertibleToNumbers = Union[str, bytes, int, float]
+
+
+if TYPE_CHECKING:
+    class RunOnce(Generic[_T]):
+
+        def __init__(self, func: Callable[[], _T]): ...
+        def __call__(self) -> _T: ...
+        def set_override(self, val: _T) -> None: ...
+        def clear_override(self) -> None: ...
+else:
+    class RunOnce:
+
+        def __init__(self, f):
+            self._override = RunOnce
+            self._cached_result = RunOnce
+            update_wrapper(self, f)
+
+        def __call__(self):
+            if self._override is not RunOnce:
+                return self._override
+            if self._cached_result is RunOnce:
+                self._cached_result = self.__wrapped__()
+            return self._cached_result
+
+        def set_override(self, val):
+            self._override = val
+
+        def clear_override(self):
+            self._override = RunOnce
+
+
+def run_once(f: Callable[[], _T]) -> RunOnce:
+    return RunOnce(f)

kitty/utils.py

@@ -23,7 +23,7 @@ from .constants import (
 )
 from .options_stub import Options
 from .rgb import Color, to_color
-from .types import ConvertibleToNumbers
+from .types import ConvertibleToNumbers, run_once
 from .typing import AddressFamily, PopenType, Socket, StartupCtx
 
 BASE = os.path.dirname(os.path.abspath(__file__))
@@ -463,7 +463,7 @@ def natsort_ints(iterable: Iterable[str]) -> List[str]:
     return sorted(iterable, key=alphanum_key)
 
 
-@lru_cache(maxsize=2)
+@run_once
 def get_editor() -> List[str]:
     import shlex
     import shutil
@@ -512,7 +512,7 @@ def resolved_shell(opts: Optional[Options] = None) -> List[str]:
     return ans
 
 
-@lru_cache(maxsize=2)
+@run_once
 def system_paths_on_macos() -> List[str]:
     entries, seen = [], set()
 

kitty_tests/graphics.py

@@ -180,12 +180,11 @@ def make_send_command(screen):
 class TestGraphics(BaseTest):
 
     def setUp(self):
-        cache_dir.override_dir = tempfile.mkdtemp()
-        cache_dir.cache_clear()
+        cache_dir.set_override(tempfile.mkdtemp())
 
     def tearDown(self):
-        os.rmdir(cache_dir.override_dir)
-        cache_dir.override_dir = None
+        os.rmdir(cache_dir())
+        cache_dir.clear_override()
 
     def test_xor_data(self):