Source code for xonsh.dirstack

# -*- coding: utf-8 -*-
"""Directory stack and associated utilities for the xonsh shell."""
import os
import glob
import argparse
import builtins
import subprocess

from xonsh.lazyasd import lazyobject
from xonsh.tools import get_sep
from xonsh.events import events
from xonsh.platform import ON_WINDOWS

DIRSTACK = []
"""A list containing the currently remembered directories."""
_unc_tempDrives = {}
""" drive: sharePath for temp drive letters we create for UNC mapping"""


def _unc_check_enabled()->bool:
    """Check whether CMD.EXE is enforcing no-UNC-as-working-directory check.

    Check can be disabled by setting {HKCU, HKLM}/SOFTWARE\Microsoft\Command Processor\DisableUNCCheck:REG_DWORD=1

    Returns:
        True if `CMD.EXE` is enforcing the check (default Windows situation)
        False if check is explicitly disabled.
    """
    if not ON_WINDOWS:
        return

    import winreg

    wval = None

    try:
        key = winreg.OpenKey(winreg.HKEY_CURRENT_USER, r'software\microsoft\command processor')
        wval, wtype = winreg.QueryValueEx(key, 'DisableUNCCheck')
        winreg.CloseKey(key)
    except OSError as e:
        pass

    if wval is None:
        try:
            key2 = winreg.OpenKey(winreg.HKEY_LOCAL_MACHINE, r'software\microsoft\command processor')
            wval, wtype = winreg.QueryValueEx(key2, 'DisableUNCCheck')
            winreg.CloseKey(key2)
        except OSError as e:  # NOQA
            pass

    return False if wval else True


def _is_unc_path(some_path)->bool:
    """True if path starts with 2 backward (or forward, due to python path hacking) slashes."""
    return len(some_path) > 1 and some_path[0] == some_path[1] and some_path[0] in (os.sep, os.altsep)


def _unc_map_temp_drive(unc_path)->str:

    """Map a new temporary drive letter for each distinct share,
    unless `CMD.EXE` is not insisting on non-UNC working directory.

    Emulating behavior of `CMD.EXE` `pushd`, create a new mapped drive (starting from Z: towards A:, skipping existing
     drive letters) for each new UNC path user selects.

    Args:
        unc_path: the path specified by user.  Assumed to be a UNC path of form \\<server>\share...

    Returns:
        a replacement for `unc_path` to be used as the actual new working directory.
        Note that the drive letter may be a the same as one already mapped if the server and share portion of `unc_path`
         is the same as one still active on the stack.
    """
    global _unc_tempDrives
    assert unc_path[1] in (os.sep, os.altsep), "unc_path is UNC form of path"

    if not _unc_check_enabled():
        return unc_path
    else:
        unc_share, rem_path = os.path.splitdrive(unc_path)
        unc_share = unc_share.casefold()
        for d in _unc_tempDrives:
            if _unc_tempDrives[d] == unc_share:
                return os.path.join(d, rem_path)

        for dord in range(ord('z'), ord('a'), -1):
            d = chr(dord) + ':'
            if not os.path.isdir(d):  # find unused drive letter starting from z:
                subprocess.check_output(['NET', 'USE', d, unc_share], universal_newlines=True)
                _unc_tempDrives[d] = unc_share
                return os.path.join(d, rem_path)


def _unc_unmap_temp_drive(left_drive, cwd):
    """Unmap a temporary drive letter if it is no longer needed.
    Called after popping `DIRSTACK` and changing to new working directory, so we need stack *and*
    new current working directory to be sure drive letter no longer needed.

    Args:
        left_drive: driveletter (and colon) of working directory we just left
        cwd: full path of new current working directory
"""

    global _unc_tempDrives

    if left_drive not in _unc_tempDrives:   # if not one we've mapped, don't unmap it
        return

    for p in DIRSTACK + [cwd]:              # if still in use , don't unmap it.
        if p.casefold().startswith(left_drive):
            return

    _unc_tempDrives.pop(left_drive)
    subprocess.check_output(['NET', 'USE', left_drive, '/delete'], universal_newlines=True)


events.doc('on_chdir', """
on_chdir(olddir: str, newdir: str) -> None

Fires when the current directory is changed for any reason.
""")


def _get_cwd():
    try:
        return os.getcwd()
    except (OSError, FileNotFoundError):
        return None


def _change_working_directory(newdir, follow_symlinks=False):
    env = builtins.__xonsh_env__
    old = env['PWD']
    new = os.path.join(old, newdir)
    absnew = os.path.abspath(new)

    if follow_symlinks:
        absnew = os.path.realpath(absnew)

    try:
        os.chdir(absnew)
    except (OSError, FileNotFoundError):
        if new.endswith(get_sep()):
            new = new[:-1]
        if os.path.basename(new) == '..':
            env['PWD'] = new
    else:
        if old is not None:
            env['OLDPWD'] = old
        if new is not None:
            env['PWD'] = absnew

    # Fire event if the path actually changed
    if old != env['PWD']:
        events.on_chdir.fire(olddir=old, newdir=env['PWD'])


def _try_cdpath(apath):
    # NOTE: this CDPATH implementation differs from the bash one.
    # In bash if a CDPATH is set, an unqualified local folder
    # is considered after all CDPATHs, example:
    # CDPATH=$HOME/src (with src/xonsh/ inside)
    # $ cd xonsh -> src/xonsh (with xonsh/xonsh)
    # a second $ cd xonsh has no effects, to move in the nested xonsh
    # in bash a full $ cd ./xonsh is needed.
    # In xonsh a relative folder is always preferred.
    env = builtins.__xonsh_env__
    cdpaths = env.get('CDPATH')
    for cdp in cdpaths:
        globber = builtins.__xonsh_expand_path__(os.path.join(cdp, apath))
        for cdpath_prefixed_path in glob.iglob(globber):
            return cdpath_prefixed_path
    return apath


[docs]def cd(args, stdin=None): """Changes the directory. If no directory is specified (i.e. if `args` is None) then this changes to the current user's home directory. """ env = builtins.__xonsh_env__ oldpwd = env.get('OLDPWD', None) cwd = env['PWD'] follow_symlinks = False if len(args) > 0 and args[0] == '-P': follow_symlinks = True del args[0] if len(args) == 0: d = os.path.expanduser('~') elif len(args) == 1: d = os.path.expanduser(args[0]) if not os.path.isdir(d): if d == '-': if oldpwd is not None: d = oldpwd else: return '', 'cd: no previous directory stored\n', 1 elif d.startswith('-'): try: num = int(d[1:]) except ValueError: return '', 'cd: Invalid destination: {0}\n'.format(d), 1 if num == 0: return None, None, 0 elif num < 0: return '', 'cd: Invalid destination: {0}\n'.format(d), 1 elif num > len(DIRSTACK): e = 'cd: Too few elements in dirstack ({0} elements)\n' return '', e.format(len(DIRSTACK)), 1 else: d = DIRSTACK[num - 1] else: d = _try_cdpath(d) else: return '', ('cd takes 0 or 1 arguments, not {0}. An additional `-P` ' 'flag can be passed in first position to follow symlinks.' '\n'.format(len(args))), 1 if not os.path.exists(d): return '', 'cd: no such file or directory: {0}\n'.format(d), 1 if not os.path.isdir(d): return '', 'cd: {0} is not a directory\n'.format(d), 1 if not os.access(d, os.X_OK): return '', 'cd: permission denied: {0}\n'.format(d), 1 if ON_WINDOWS and _is_unc_path(d) and _unc_check_enabled() and (not env.get('AUTO_PUSHD')): return '', "cd: can't cd to UNC path on Windows, unless $AUTO_PUSHD set or reg entry " \ + r'HKCU\SOFTWARE\MICROSOFT\Command Processor\DisableUNCCheck:DWORD = 1' + '\n', 1 # now, push the directory onto the dirstack if AUTO_PUSHD is set if cwd is not None and env.get('AUTO_PUSHD'): pushd(['-n', '-q', cwd]) if ON_WINDOWS and _is_unc_path(d): d = _unc_map_temp_drive(d) _change_working_directory(d, follow_symlinks) return None, None, 0
@lazyobject def pushd_parser(): parser = argparse.ArgumentParser(prog="pushd") parser.add_argument('dir', nargs='?') parser.add_argument('-n', dest='cd', help='Suppresses the normal change of directory when' ' adding directories to the stack, so that only the' ' stack is manipulated.', action='store_false') parser.add_argument('-q', dest='quiet', help='Do not call dirs, regardless of $PUSHD_SILENT', action='store_true') return parser
[docs]def pushd(args, stdin=None): """xonsh command: pushd Adds a directory to the top of the directory stack, or rotates the stack, making the new top of the stack the current working directory. On Windows, if the path is a UNC path (begins with `\\<server>\<share>`) and if the `DisableUNCCheck` registry value is not enabled, creates a temporary mapped drive letter and sets the working directory there, emulating behavior of `PUSHD` in `CMD.EXE` """ global DIRSTACK try: args = pushd_parser.parse_args(args) except SystemExit: return None, None, 1 env = builtins.__xonsh_env__ pwd = env['PWD'] if env.get('PUSHD_MINUS', False): BACKWARD = '-' FORWARD = '+' else: BACKWARD = '+' FORWARD = '-' if args.dir is None: try: new_pwd = DIRSTACK.pop(0) except IndexError: e = 'pushd: Directory stack is empty\n' return None, e, 1 elif os.path.isdir(args.dir): new_pwd = args.dir else: try: num = int(args.dir[1:]) except ValueError: e = 'Invalid argument to pushd: {0}\n' return None, e.format(args.dir), 1 if num < 0: e = 'Invalid argument to pushd: {0}\n' return None, e.format(args.dir), 1 if num > len(DIRSTACK): e = 'Too few elements in dirstack ({0} elements)\n' return None, e.format(len(DIRSTACK)), 1 elif args.dir.startswith(FORWARD): if num == len(DIRSTACK): new_pwd = None else: new_pwd = DIRSTACK.pop(len(DIRSTACK) - 1 - num) elif args.dir.startswith(BACKWARD): if num == 0: new_pwd = None else: new_pwd = DIRSTACK.pop(num - 1) else: e = 'Invalid argument to pushd: {0}\n' return None, e.format(args.dir), 1 if new_pwd is not None: if ON_WINDOWS and _is_unc_path(new_pwd): new_pwd = _unc_map_temp_drive(new_pwd) if args.cd: DIRSTACK.insert(0, os.path.expanduser(pwd)) _change_working_directory(new_pwd) else: DIRSTACK.insert(0, os.path.expanduser(new_pwd)) maxsize = env.get('DIRSTACK_SIZE') if len(DIRSTACK) > maxsize: DIRSTACK = DIRSTACK[:maxsize] if not args.quiet and not env.get('PUSHD_SILENT'): return dirs([], None) return None, None, 0
@lazyobject def popd_parser(): parser = argparse.ArgumentParser(prog="popd") parser.add_argument('dir', nargs='?') parser.add_argument('-n', dest='cd', help='Suppresses the normal change of directory when' ' adding directories to the stack, so that only the' ' stack is manipulated.', action='store_false') parser.add_argument('-q', dest='quiet', help='Do not call dirs, regardless of $PUSHD_SILENT', action='store_true') return parser
[docs]def popd(args, stdin=None): """ xonsh command: popd Removes entries from the directory stack. """ global DIRSTACK try: args = pushd_parser.parse_args(args) except SystemExit: return None, None, 1 env = builtins.__xonsh_env__ if env.get('PUSHD_MINUS'): BACKWARD = '-' FORWARD = '+' else: BACKWARD = '-' FORWARD = '+' if args.dir is None: try: new_pwd = DIRSTACK.pop(0) except IndexError: e = 'popd: Directory stack is empty\n' return None, e, 1 else: try: num = int(args.dir[1:]) except ValueError: e = 'Invalid argument to popd: {0}\n' return None, e.format(args.dir), 1 if num < 0: e = 'Invalid argument to popd: {0}\n' return None, e.format(args.dir), 1 if num > len(DIRSTACK): e = 'Too few elements in dirstack ({0} elements)\n' return None, e.format(len(DIRSTACK)), 1 elif args.dir.startswith(FORWARD): if num == len(DIRSTACK): new_pwd = DIRSTACK.pop(0) else: new_pwd = None DIRSTACK.pop(len(DIRSTACK) - 1 - num) elif args.dir.startswith(BACKWARD): if num == 0: new_pwd = DIRSTACK.pop(0) else: new_pwd = None DIRSTACK.pop(num - 1) else: e = 'Invalid argument to popd: {0}\n' return None, e.format(args.dir), 1 if new_pwd is not None: e = None if args.cd: env = builtins.__xonsh_env__ pwd = env['PWD'] _change_working_directory(new_pwd) if ON_WINDOWS: drive, rem_path = os.path.splitdrive(pwd) _unc_unmap_temp_drive(drive.casefold(), new_pwd) if not args.quiet and not env.get('PUSHD_SILENT'): return dirs([], None) return None, None, 0
@lazyobject def dirs_parser(): parser = argparse.ArgumentParser(prog="dirs") parser.add_argument('N', nargs='?') parser.add_argument('-c', dest='clear', help='Clears the directory stack by deleting all of' ' the entries.', action='store_true') parser.add_argument('-p', dest='print_long', help='Print the directory stack with one entry per' ' line.', action='store_true') parser.add_argument('-v', dest='verbose', help='Print the directory stack with one entry per' ' line, prefixing each entry with its index in the' ' stack.', action='store_true') parser.add_argument('-l', dest='long', help='Produces a longer listing; the default listing' ' format uses a tilde to denote the home directory.', action='store_true') return parser
[docs]def dirs(args, stdin=None): """xonsh command: dirs Displays the list of currently remembered directories. Can also be used to clear the directory stack. """ global DIRSTACK try: args = dirs_parser.parse_args(args) except SystemExit: return None, None env = builtins.__xonsh_env__ dirstack = [os.path.expanduser(env['PWD'])] + DIRSTACK if env.get('PUSHD_MINUS'): BACKWARD = '-' FORWARD = '+' else: BACKWARD = '-' FORWARD = '+' if args.clear: DIRSTACK = [] return None, None, 0 if args.long: o = dirstack else: d = os.path.expanduser('~') o = [i.replace(d, '~') for i in dirstack] if args.verbose: out = '' pad = len(str(len(o) - 1)) for (ix, e) in enumerate(o): blanks = ' ' * (pad - len(str(ix))) out += '\n{0}{1} {2}'.format(blanks, ix, e) out = out[1:] elif args.print_long: out = '\n'.join(o) else: out = ' '.join(o) N = args.N if N is not None: try: num = int(N[1:]) except ValueError: e = 'Invalid argument to dirs: {0}\n' return None, e.format(N), 1 if num < 0: e = 'Invalid argument to dirs: {0}\n' return None, e.format(len(o)), 1 if num >= len(o): e = 'Too few elements in dirstack ({0} elements)\n' return None, e.format(len(o)), 1 if N.startswith(BACKWARD): idx = num elif N.startswith(FORWARD): idx = len(o) - 1 - num else: e = 'Invalid argument to dirs: {0}\n' return None, e.format(N), 1 out = o[idx] return out + '\n', None, 0