"""Tools to help interface with foreign shells, such as Bash."""
import collections.abc as cabc
import functools
import os
import re
import shlex
import subprocess
import sys
import tempfile
import warnings
from xonsh.built_ins import XSH
from xonsh.lazyasd import lazyobject
from xonsh.platform import ON_CYGWIN, ON_MSYS, ON_WINDOWS
from xonsh.tools import ensure_string, to_bool
COMMAND = """{seterrprevcmd}
{prevcmd}
echo __XONSH_ENV_BEG__
{envcmd}
echo __XONSH_ENV_END__
echo __XONSH_ALIAS_BEG__
{aliascmd}
echo __XONSH_ALIAS_END__
echo __XONSH_FUNCS_BEG__
{funcscmd}
echo __XONSH_FUNCS_END__
{postcmd}
{seterrpostcmd}"""
DEFAULT_BASH_FUNCSCMD = """# get function names from declare
declstr=$(echo $(declare -F))
read -r -a decls <<< $declstr
for((n=0;n<${#decls[@]};n++)); do
if (( $(($n % 3 )) == 2 )); then
echo -n "${decls[$n]} "
fi
done
echo"""
DEFAULT_ZSH_FUNCSCMD = """# get function names
for name in ${(ok)functions}; do
echo -n "$name "
done
echo"""
# mapping of shell name aliases to keys in other lookup dictionaries.
@lazyobject
def CANON_SHELL_NAMES():
return {
"bash": "bash",
"/bin/bash": "bash",
"zsh": "zsh",
"/bin/zsh": "zsh",
"/usr/bin/zsh": "zsh",
"cmd": "cmd",
"cmd.exe": "cmd",
}
@lazyobject
def DEFAULT_ENVCMDS():
return {"bash": "env", "zsh": "env", "cmd": "set"}
@lazyobject
def DEFAULT_ALIASCMDS():
return {"bash": "alias", "zsh": "alias -L", "cmd": ""}
@lazyobject
def DEFAULT_FUNCSCMDS():
return {"bash": DEFAULT_BASH_FUNCSCMD, "zsh": DEFAULT_ZSH_FUNCSCMD, "cmd": ""}
@lazyobject
def DEFAULT_SOURCERS():
return {"bash": "source", "zsh": "source", "cmd": "call"}
@lazyobject
def DEFAULT_TMPFILE_EXT():
return {"bash": ".sh", "zsh": ".zsh", "cmd": ".bat"}
@lazyobject
def DEFAULT_RUNCMD():
return {"bash": "-c", "zsh": "-c", "cmd": "/C"}
@lazyobject
def DEFAULT_SETERRPREVCMD():
return {"bash": "set -e", "zsh": "set -e", "cmd": "@echo off"}
@lazyobject
def DEFAULT_SETERRPOSTCMD():
return {"bash": "", "zsh": "", "cmd": "if errorlevel 1 exit 1"}
[docs]
@functools.lru_cache
def foreign_shell_data(
shell,
interactive=True,
login=False,
envcmd=None,
aliascmd=None,
extra_args=(),
currenv=None,
safe=True,
prevcmd="",
postcmd="",
funcscmd=None,
sourcer=None,
use_tmpfile=False,
tmpfile_ext=None,
runcmd=None,
seterrprevcmd=None,
seterrpostcmd=None,
show=False,
dryrun=False,
files=(),
):
"""Extracts data from a foreign (non-xonsh) shells. Currently this gets
the environment, aliases, and functions but may be extended in the future.
Parameters
----------
shell : str
The name of the shell, such as 'bash' or '/bin/sh'.
interactive : bool, optional
Whether the shell should be run in interactive mode.
login : bool, optional
Whether the shell should be a login shell.
envcmd : str or None, optional
The command to generate environment output with.
aliascmd : str or None, optional
The command to generate alias output with.
extra_args : tuple of str, optional
Additional command line options to pass into the shell.
currenv : tuple of items or None, optional
Manual override for the current environment.
safe : bool, optional
Flag for whether or not to safely handle exceptions and other errors.
prevcmd : str, optional
A command to run in the shell before anything else, useful for
sourcing and other commands that may require environment recovery.
postcmd : str, optional
A command to run after everything else, useful for cleaning up any
damage that the prevcmd may have caused.
funcscmd : str or None, optional
This is a command or script that can be used to determine the names
and locations of any functions that are native to the foreign shell.
This command should print *only* a JSON object that maps
function names to the filenames where the functions are defined.
If this is None, then a default script will attempted to be looked
up based on the shell name. Callable wrappers for these functions
will be returned in the aliases dictionary.
sourcer : str or None, optional
How to source a foreign shell file for purposes of calling functions
in that shell. If this is None, a default value will attempt to be
looked up based on the shell name.
use_tmpfile : bool, optional
This specifies if the commands are written to a tmp file or just
parsed directly to the shell
tmpfile_ext : str or None, optional
If tmpfile is True this sets specifies the extension used.
runcmd : str or None, optional
Command line switches to use when running the script, such as
-c for Bash and /C for cmd.exe.
seterrprevcmd : str or None, optional
Command that enables exit-on-error for the shell that is run at the
start of the script. For example, this is "set -e" in Bash. To disable
exit-on-error behavior, simply pass in an empty string.
seterrpostcmd : str or None, optional
Command that enables exit-on-error for the shell that is run at the end
of the script. For example, this is "if errorlevel 1 exit 1" in
cmd.exe. To disable exit-on-error behavior, simply pass in an
empty string.
show : bool, optional
Whether or not to display the script that will be run.
dryrun : bool, optional
Whether or not to actually run and process the command.
files : tuple of str, optional
Paths to source.
Returns
-------
env : dict
Dictionary of shell's environment. (None if the subproc command fails)
aliases : dict
Dictionary of shell's aliases, this includes foreign function
wrappers.(None if the subproc command fails)
"""
cmd = [shell]
cmd.extend(extra_args) # needs to come here for GNU long options
if interactive:
cmd.append("-i")
if login:
cmd.append("-l")
shkey = CANON_SHELL_NAMES[shell]
envcmd = DEFAULT_ENVCMDS.get(shkey, "env") if envcmd is None else envcmd
aliascmd = DEFAULT_ALIASCMDS.get(shkey, "alias") if aliascmd is None else aliascmd
funcscmd = DEFAULT_FUNCSCMDS.get(shkey, "echo {}") if funcscmd is None else funcscmd
tmpfile_ext = (
DEFAULT_TMPFILE_EXT.get(shkey, "sh") if tmpfile_ext is None else tmpfile_ext
)
runcmd = DEFAULT_RUNCMD.get(shkey, "-c") if runcmd is None else runcmd
seterrprevcmd = (
DEFAULT_SETERRPREVCMD.get(shkey, "") if seterrprevcmd is None else seterrprevcmd
)
seterrpostcmd = (
DEFAULT_SETERRPOSTCMD.get(shkey, "") if seterrpostcmd is None else seterrpostcmd
)
command = COMMAND.format(
envcmd=envcmd,
aliascmd=aliascmd,
prevcmd=prevcmd,
postcmd=postcmd,
funcscmd=funcscmd,
seterrprevcmd=seterrprevcmd,
seterrpostcmd=seterrpostcmd,
).strip()
if show:
print(command)
if dryrun:
return None, None
cmd.append(runcmd)
if not use_tmpfile:
cmd.append(command)
else:
tmpfile = tempfile.NamedTemporaryFile(suffix=tmpfile_ext, delete=False)
tmpfile.write(command.encode("utf8"))
tmpfile.close()
cmd.append(tmpfile.name)
if currenv is None and XSH.env:
currenv = XSH.env.detype()
elif currenv is not None:
currenv = dict(currenv)
try:
s = subprocess.check_output(
cmd,
stderr=subprocess.PIPE,
env=currenv,
# start new session to avoid hangs
# (doesn't work on Cygwin though)
start_new_session=((not ON_CYGWIN) and (not ON_MSYS)),
text=True,
)
except (subprocess.CalledProcessError, FileNotFoundError):
if not safe:
raise
return None, None
finally:
if use_tmpfile:
os.remove(tmpfile.name)
env = parse_env(s)
aliases = parse_aliases(
s,
shell=shell,
sourcer=sourcer,
files=files,
extra_args=extra_args,
)
funcs = parse_funcs(
s,
shell=shell,
sourcer=sourcer,
files=files,
extra_args=extra_args,
)
aliases.update(funcs)
return env, aliases
@lazyobject
def ENV_RE():
return re.compile("__XONSH_ENV_BEG__\n(.*)" "__XONSH_ENV_END__", flags=re.DOTALL)
@lazyobject
def ENV_SPLIT_RE():
return re.compile("^([^=]+)=([^=]*|[^\n]*)$", flags=re.DOTALL | re.MULTILINE)
[docs]
def parse_env(s):
"""Parses the environment portion of string into a dict."""
m = ENV_RE.search(s)
if m is None:
return {}
g1 = m.group(1)
g1 = g1[:-1] if g1.endswith("\n") else g1
env = dict(ENV_SPLIT_RE.findall(g1))
return env
@lazyobject
def ALIAS_RE():
return re.compile(
"__XONSH_ALIAS_BEG__\n(.*)" "__XONSH_ALIAS_END__", flags=re.DOTALL
)
@lazyobject
def FS_EXEC_ALIAS_RE():
return re.compile(r";|`|\$\(")
[docs]
def parse_aliases(s, shell, sourcer=None, files=(), extra_args=()):
"""Parses the aliases portion of string into a dict."""
m = ALIAS_RE.search(s)
if m is None:
return {}
g1 = m.group(1)
g1 = g1.replace("\\\n", " ")
items = [
line.split("=", 1)
for line in g1.splitlines()
if line.startswith("alias ") and "=" in line
]
aliases = {}
for key, value in items:
try:
key = key[6:] # lstrip 'alias '
# undo bash's weird quoting of single quotes (sh_single_quote)
value = value.replace("'\\''", "'")
# strip one single quote at the start and end of value
if value[0] == "'" and value[-1] == "'":
value = value[1:-1]
# now compute actual alias
if FS_EXEC_ALIAS_RE.search(value) is None:
# simple list of args alias
value = shlex.split(value)
else:
# alias is more complex, use ExecAlias, but via shell
value = ForeignShellExecAlias(
src=value,
shell=shell,
sourcer=sourcer,
files=files,
extra_args=extra_args,
)
except ValueError as exc:
warnings.warn(
f'could not parse alias "{key}": {exc!r}',
RuntimeWarning,
stacklevel=2,
)
continue
aliases[key] = value
return aliases
@lazyobject
def FUNCS_RE():
return re.compile(
"__XONSH_FUNCS_BEG__\n(.+)\n" "__XONSH_FUNCS_END__", flags=re.DOTALL
)
[docs]
def parse_funcs(s, shell, sourcer=None, files=(), extra_args=()):
"""Parses the funcs portion of a string into a dict of callable foreign
function wrappers.
"""
m = FUNCS_RE.search(s)
if m is None:
return {}
g1 = m.group(1)
if ON_WINDOWS:
g1 = g1.replace(os.sep, os.altsep)
funcnames = g1.split()
funcs = {}
for funcname in funcnames:
if funcname.startswith("_"):
continue # skip private functions and invalid files
wrapper = ForeignShellFunctionAlias(
funcname=funcname,
shell=shell,
sourcer=sourcer,
files=files,
extra_args=extra_args,
)
funcs[funcname] = wrapper
return funcs
[docs]
class ForeignShellBaseAlias:
"""This class is responsible for calling foreign shell functions as if
they were aliases. This does not currently support taking stdin.
"""
INPUT = "echo ForeignShellBaseAlias {shell} {args}\n"
def __init__(self, shell, sourcer=None, files=(), extra_args=()):
"""
Parameters
----------
shell : str
Name or path to shell
sourcer : str or None, optional
Command to source foreign files with.
files : tuple of str, optional
Paths to source.
extra_args : tuple of str, optional
Additional command line options to pass into the shell.
"""
sourcer = DEFAULT_SOURCERS.get(shell, "source") if sourcer is None else sourcer
self.shell = shell
self.sourcer = sourcer
self.files = files
self.extra_args = extra_args
def _input_kwargs(self):
return {
"shell": self.shell,
"extra_args": self.extra_args,
}
def __eq__(self, other):
if not hasattr(other, "_input_kwargs") or not callable(other._input_kwargs):
return NotImplemented
return self._input_kwargs() == other._input_kwargs()
def __call__(
self, args, stdin=None, stdout=None, stderr=None, spec=None, stack=None
):
args, streaming = self._is_streaming(args)
input = self.INPUT.format(args=" ".join(args), **self._input_kwargs())
if len(self.files) > 0:
input = "".join([f'{self.sourcer} "{f}"\n' for f in self.files]) + input
cmd = [self.shell] + list(self.extra_args) + ["-ic", input]
env = XSH.env
denv = env.detype()
if streaming:
subprocess.check_call(cmd, env=denv)
out = None
else:
out = subprocess.check_output(cmd, env=denv, stderr=subprocess.STDOUT)
out = out.decode(
encoding=env.get("XONSH_ENCODING"),
errors=env.get("XONSH_ENCODING_ERRORS"),
)
out = out.replace("\r\n", "\n")
return out
def __repr__(self):
return (
self.__class__.__name__
+ "("
+ ", ".join([f"{k}={v!r}" for k, v in sorted(self._input_kwargs().items())])
+ ")"
)
@staticmethod
def _is_streaming(args):
"""Test and modify args if --xonsh-stream is present."""
if "--xonsh-nostream" not in args:
return args, True
args = list(args)
args.remove("--xonsh-nostream")
return args, False
[docs]
class ForeignShellFunctionAlias(ForeignShellBaseAlias):
"""This class is responsible for calling foreign shell functions as if
they were aliases. This does not currently support taking stdin.
"""
INPUT = "{funcname} {args}\n"
def __init__(self, funcname, shell, sourcer=None, files=(), extra_args=()):
"""
Parameters
----------
funcname : str
function name
shell : str
Name or path to shell
sourcer : str or None, optional
Command to source foreign files with.
files : tuple of str, optional
Paths to source.
extra_args : tuple of str, optional
Additional command line options to pass into the shell.
"""
super().__init__(
shell=shell, sourcer=sourcer, files=files, extra_args=extra_args
)
self.funcname = funcname
def _input_kwargs(self):
inp = super()._input_kwargs()
inp["funcname"] = self.funcname
return inp
[docs]
class ForeignShellExecAlias(ForeignShellBaseAlias):
"""Provides a callable alias for source code in a foreign shell."""
INPUT = "{src} {args}\n"
def __init__(
self,
src,
shell,
sourcer=None,
files=(),
extra_args=(),
):
"""
Parameters
----------
src : str
Source code in the shell language
shell : str
Name or path to shell
sourcer : str or None, optional
Command to source foreign files with.
files : tuple of str, optional
Paths to source.
extra_args : tuple of str, optional
Additional command line options to pass into the shell.
"""
super().__init__(
shell=shell, sourcer=sourcer, files=files, extra_args=extra_args
)
self.src = src.strip()
def _input_kwargs(self):
inp = super()._input_kwargs()
inp["src"] = self.src
return inp
@lazyobject
def VALID_SHELL_PARAMS():
return frozenset(
[
"shell",
"interactive",
"login",
"envcmd",
"aliascmd",
"extra_args",
"currenv",
"safe",
"prevcmd",
"postcmd",
"funcscmd",
"sourcer",
]
)
[docs]
def ensure_shell(shell):
"""Ensures that a mapping follows the shell specification."""
if not isinstance(shell, cabc.MutableMapping):
shell = dict(shell)
shell_keys = set(shell.keys())
if not (shell_keys <= VALID_SHELL_PARAMS):
raise KeyError(f"unknown shell keys: {shell_keys - VALID_SHELL_PARAMS}")
shell["shell"] = ensure_string(shell["shell"]).lower()
if "interactive" in shell_keys:
shell["interactive"] = to_bool(shell["interactive"])
if "login" in shell_keys:
shell["login"] = to_bool(shell["login"])
if "envcmd" in shell_keys:
shell["envcmd"] = (
None if shell["envcmd"] is None else ensure_string(shell["envcmd"])
)
if "aliascmd" in shell_keys:
shell["aliascmd"] = (
None if shell["aliascmd"] is None else ensure_string(shell["aliascmd"])
)
if "extra_args" in shell_keys and not isinstance(shell["extra_args"], tuple):
shell["extra_args"] = tuple(map(ensure_string, shell["extra_args"]))
if "currenv" in shell_keys and not isinstance(shell["currenv"], tuple):
ce = shell["currenv"]
if isinstance(ce, cabc.Mapping):
ce = tuple((ensure_string(k), v) for k, v in ce.items())
elif isinstance(ce, cabc.Sequence):
ce = tuple((ensure_string(k), v) for k, v in ce)
else:
raise RuntimeError("unrecognized type for currenv")
shell["currenv"] = ce
if "safe" in shell_keys:
shell["safe"] = to_bool(shell["safe"])
if "prevcmd" in shell_keys:
shell["prevcmd"] = ensure_string(shell["prevcmd"])
if "postcmd" in shell_keys:
shell["postcmd"] = ensure_string(shell["postcmd"])
if "funcscmd" in shell_keys:
shell["funcscmd"] = (
None if shell["funcscmd"] is None else ensure_string(shell["funcscmd"])
)
if "sourcer" in shell_keys:
shell["sourcer"] = (
None if shell["sourcer"] is None else ensure_string(shell["sourcer"])
)
if "seterrprevcmd" in shell_keys:
shell["seterrprevcmd"] = (
None
if shell["seterrprevcmd"] is None
else ensure_string(shell["seterrprevcmd"])
)
if "seterrpostcmd" in shell_keys:
shell["seterrpostcmd"] = (
None
if shell["seterrpostcmd"] is None
else ensure_string(shell["seterrpostcmd"])
)
return shell
[docs]
def load_foreign_envs(shells):
"""Loads environments from foreign shells.
Parameters
----------
shells : sequence of dicts
An iterable of dicts that can be passed into foreign_shell_data() as
keyword arguments.
Returns
-------
env : dict
A dictionary of the merged environments.
"""
env = {}
for shell in shells:
shell = ensure_shell(shell)
shenv, _ = foreign_shell_data(**shell)
if shenv:
env.update(shenv)
return env
[docs]
def load_foreign_aliases(shells):
"""Loads aliases from foreign shells.
Parameters
----------
shells : sequence of dicts
An iterable of dicts that can be passed into foreign_shell_data() as
keyword arguments.
Returns
-------
aliases : dict
A dictionary of the merged aliases.
"""
aliases = {}
xonsh_aliases = XSH.aliases
for shell in shells:
shell = ensure_shell(shell)
_, shaliases = foreign_shell_data(**shell)
if not XSH.env.get("FOREIGN_ALIASES_OVERRIDE"):
shaliases = {} if shaliases is None else shaliases
for alias in set(shaliases) & set(xonsh_aliases):
del shaliases[alias]
if XSH.env.get("XONSH_DEBUG") >= 1:
print(
f"aliases: ignoring alias {alias!r} of shell {shell['shell']!r} "
"which tries to override xonsh alias.",
file=sys.stderr,
)
aliases.update(shaliases)
return aliases