from __future__ import annotations
import os
from os.path import exists
from os.path import join
from os.path import splitext
from subprocess import check_call
from typing import Dict
from typing import List
from typing import Mapping
from typing import Optional
from .compat import is_posix
from .exc import CommandError
def open_in_editor(
filename: str, environ: Optional[Dict[str, str]] = None
) -> None:
"""
Opens the given file in a text editor. If the environment variable
``EDITOR`` is set, this is taken as preference.
Otherwise, a list of commonly installed editors is tried.
If no editor matches, an :py:exc:`OSError` is raised.
:param filename: The filename to open. Will be passed verbatim to the
editor command.
:param environ: An optional drop-in replacement for ``os.environ``. Used
mainly for testing.
"""
env = os.environ if environ is None else environ
try:
editor = _find_editor(env)
check_call([editor, filename])
except Exception as exc:
raise CommandError("Error executing editor (%s)" % (exc,)) from exc
def _find_editor(environ: Mapping[str, str]) -> str:
candidates = _default_editors()
for i, var in enumerate(("EDITOR", "VISUAL")):
if var in environ:
user_choice = environ[var]
if exists(user_choice):
return user_choice
if os.sep not in user_choice:
candidates.insert(i, user_choice)
for candidate in candidates:
path = _find_executable(candidate, environ)
if path is not None:
return path
raise OSError(
"No suitable editor found. Please set the "
'"EDITOR" or "VISUAL" environment variables'
)
def _find_executable(
candidate: str, environ: Mapping[str, str]
) -> Optional[str]:
# Assuming this is on the PATH, we need to determine it's absolute
# location. Otherwise, ``check_call`` will fail
if not is_posix and splitext(candidate)[1] != ".exe":
candidate += ".exe"
for path in environ.get("PATH", "").split(os.pathsep):
value = join(path, candidate)
if exists(value):
return value
return None
def _default_editors() -> List[str]:
# Look for an editor. Prefer the user's choice by env-var, fall back to
# most commonly installed editor (nano/vim)
if is_posix:
return ["sensible-editor", "editor", "nano", "vim", "code"]
else:
return ["code.exe", "notepad++.exe", "notepad.exe"]
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