Source code for xonsh.base_shell

# -*- coding: utf-8 -*-
"""The base class for xonsh shell"""
import io
import os
import sys
import time
import builtins

from xonsh.tools import (XonshError, print_exception, DefaultNotGiven,
                         check_for_partial_string, format_std_prepost,
                         get_line_continuation)
from xonsh.platform import HAS_PYGMENTS, ON_WINDOWS
from xonsh.codecache import (should_use_cache, code_cache_name,
                             code_cache_check, get_cache_filename,
                             update_cache, run_compiled_code)
from xonsh.completer import Completer
from xonsh.prompt.base import multiline_prompt, PromptFormatter
from xonsh.events import events
from xonsh.shell import transform_command
from xonsh.lazyimps import pygments, pyghooks
from xonsh.ansi_colors import ansi_partial_color_format

if ON_WINDOWS:
    import ctypes
    kernel32 = ctypes.windll.kernel32
    kernel32.SetConsoleTitleW.argtypes = [ctypes.c_wchar_p]


class _TeeStdBuf(io.RawIOBase):
    """A dispatcher for bytes to two buffers, as std stream buffer and an
    in memory buffer.
    """

    def __init__(self, stdbuf, membuf, encoding=None, errors=None, prestd=b'',
                 poststd=b''):
        """
        Parameters
        ----------
        stdbuf : BytesIO-like or StringIO-like
            The std stream buffer.
        membuf : BytesIO-like
            The in memory stream buffer.
        encoding : str or None, optional
            The encoding of the stream. Only used if stdbuf is a text stream,
            rather than a binary one.
        errors : str or None, optional
            The error form for the encoding of the stream. Only used if stdbuf
            is a text stream, rather than a binary one.
        prestd : bytes, optional
            The prefix to prepend to the standard buffer.
        poststd : bytes, optional
            The postfix to append to the standard buffer.
        """
        self.stdbuf = stdbuf
        self.membuf = membuf
        self.encoding = encoding
        self.errors = errors
        self.prestd = prestd
        self.poststd = poststd
        self._std_is_binary = not hasattr(stdbuf, 'encoding')

    def fileno(self):
        """Returns the file descriptor of the std buffer."""
        return self.stdbuf.fileno()

    def seek(self, offset, whence=io.SEEK_SET):
        """Sets the location in both the stdbuf and the membuf."""
        self.stdbuf.seek(offset, whence)
        self.membuf.seek(offset, whence)

    def truncate(self, size=None):
        """Truncate both buffers."""
        self.stdbuf.truncate(size)
        self.membuf.truncate(size)

    def readinto(self, b):
        """Read bytes into buffer from both streams."""
        if self._std_is_binary:
            self.stdbuf.readinto(b)
        return self.membuf.readinto(b)

    def write(self, b):
        """Write bytes into both buffers."""
        std_b = b
        if self.prestd:
            std_b = self.prestd + b
        if self.poststd:
            std_b += self.poststd
        # write to stdbuf
        if self._std_is_binary:
            self.stdbuf.write(std_b)
        else:
            self.stdbuf.write(std_b.decode(encoding=self.encoding,
                                           errors=self.errors))
        return self.membuf.write(b)


class _TeeStd(io.TextIOBase):
    """Tees a std stream into an in-memory container and the original stream."""

    def __init__(self, name, mem, prestd='', poststd=''):
        """
        Parameters
        ----------
        name : str
            The name of the buffer in the sys module, e.g. 'stdout'.
        mem : io.TextIOBase-like
            The in-memory text-based representation.
        prestd : str, optional
            The prefix to prepend to the standard stream.
        poststd : str, optional
            The postfix to append to the standard stream.
        """
        self._name = name
        self.std = std = getattr(sys, name)
        self.mem = mem
        self.prestd = prestd
        self.poststd = poststd
        preb = prestd.encode(encoding=mem.encoding, errors=mem.errors)
        postb = poststd.encode(encoding=mem.encoding, errors=mem.errors)
        if hasattr(std, 'buffer'):
            buffer = _TeeStdBuf(std.buffer, mem.buffer,
                                prestd=preb, poststd=postb)
        else:
            # TextIO does not have buffer as part of the API, so std streams
            # may not either.
            buffer = _TeeStdBuf(std, mem.buffer, encoding=mem.encoding,
                                errors=mem.errors, prestd=preb, poststd=postb)
        self.buffer = buffer
        setattr(sys, name, self)

    @property
    def encoding(self):
        """The encoding of the in-memory buffer."""
        return self.mem.encoding

    @property
    def errors(self):
        """The errors of the in-memory buffer."""
        return self.mem.errors

    @property
    def newlines(self):
        """The newlines of the in-memory buffer."""
        return self.mem.newlines

    def _replace_std(self):
        std = self.std
        if std is None:
            return
        setattr(sys, self._name, std)
        self.std = self._name = None

    def __del__(self):
        self._replace_std()

    def close(self):
        """Restores the original std stream."""
        self._replace_std()

    def write(self, s):
        """Writes data to the original std stream and the in-memory object."""
        self.mem.write(s)
        if self.std is None:
            return
        std_s = s
        if self.prestd:
            std_s = self.prestd + std_s
        if self.poststd:
            std_s += self.poststd
        self.std.write(std_s)

    def flush(self):
        """Flushes both the original stdout and the buffer."""
        self.std.flush()
        self.mem.flush()

    def fileno(self):
        """Tunnel fileno() calls to the std stream."""
        return self.std.fileno()

    def seek(self, offset, whence=io.SEEK_SET):
        """Seek to a location in both streams."""
        self.std.seek(offset, whence)
        self.mem.seek(offset, whence)

    def truncate(self, size=None):
        """Seek to a location in both streams."""
        self.std.truncate(size)
        self.mem.truncate(size)

    def detach(self):
        """This operation is not supported."""
        raise io.UnsupportedOperation

    def read(self, size=None):
        """Read from the in-memory stream and seek to a new location in the
        std stream.
        """
        s = self.mem.read(size)
        loc = self.std.tell()
        self.std.seek(loc + len(s))
        return s

    def readline(self, size=-1):
        """Read a line from the in-memory stream and seek to a new location
        in the std stream.
        """
        s = self.mem.readline(size)
        loc = self.std.tell()
        self.std.seek(loc + len(s))
        return s


[docs]class Tee: """Class that merges tee'd stdout and stderr into a single strea,. This represents what a user would actually see on the command line. This class as the same interface as io.TextIOWrapper, except that the buffer is optional. """ # pylint is a stupid about counting public methods when using inheritance. # pylint: disable=too-few-public-methods def __init__(self, buffer=None, encoding=None, errors=None, newline=None, line_buffering=False, write_through=False): self.buffer = io.BytesIO() if buffer is None else buffer self.memory = io.TextIOWrapper(self.buffer, encoding=encoding, errors=errors, newline=newline, line_buffering=line_buffering, write_through=write_through) self.stdout = _TeeStd('stdout', self.memory) env = builtins.__xonsh_env__ prestderr = format_std_prepost(env.get('XONSH_STDERR_PREFIX')) poststderr = format_std_prepost(env.get('XONSH_STDERR_POSTFIX')) self.stderr = _TeeStd('stderr', self.memory, prestd=prestderr, poststd=poststderr) @property def line_buffering(self): return self.memory.line_buffering def __del__(self): del self.stdout, self.stderr self.stdout = self.stderr = None
[docs] def close(self): """Closes the buffer as well as the stdout and stderr tees.""" self.stdout.close() self.stderr.close() self.memory.close()
[docs] def getvalue(self): """Gets the current contents of the in-memory buffer.""" m = self.memory loc = m.tell() m.seek(0) s = m.read() m.seek(loc) return s
[docs]class BaseShell(object): """The xonsh shell.""" def __init__(self, execer, ctx, **kwargs): super().__init__() self.execer = execer self.ctx = ctx self.completer = Completer() if kwargs.get('completer', True) else None self.buffer = [] self.need_more_lines = False self.mlprompt = None self._styler = DefaultNotGiven self.prompt_formatter = PromptFormatter() self.accumulated_inputs = '' @property def styler(self): if self._styler is DefaultNotGiven: if HAS_PYGMENTS: from xonsh.pyghooks import XonshStyle env = builtins.__xonsh_env__ self._styler = XonshStyle(env.get('XONSH_COLOR_STYLE')) else: self._styler = None return self._styler @styler.setter def styler(self, value): self._styler = value @styler.deleter def styler(self): self._styler = DefaultNotGiven
[docs] def emptyline(self): """Called when an empty line has been entered.""" self.need_more_lines = False self.default('')
[docs] def singleline(self, **kwargs): """Reads a single line of input from the shell.""" msg = '{0} has not implemented singleline().' raise RuntimeError(msg.format(self.__class__.__name__))
[docs] def precmd(self, line): """Called just before execution of line.""" return line if self.need_more_lines else line.lstrip()
[docs] def default(self, line): """Implements code execution.""" line = line if line.endswith('\n') else line + '\n' src, code = self.push(line) if code is None: return events.on_precommand.fire(cmd=src) env = builtins.__xonsh_env__ hist = builtins.__xonsh_history__ # pylint: disable=no-member ts1 = None enc = env.get('XONSH_ENCODING') err = env.get('XONSH_ENCODING_ERRORS') tee = Tee(encoding=enc, errors=err) try: ts0 = time.time() run_compiled_code(code, self.ctx, None, 'single') ts1 = time.time() if hist is not None and hist.last_cmd_rtn is None: hist.last_cmd_rtn = 0 # returncode for success except XonshError as e: print(e.args[0], file=sys.stderr) if hist is not None and hist.last_cmd_rtn is None: hist.last_cmd_rtn = 1 # return code for failure except Exception: # pylint: disable=broad-except print_exception() if hist is not None and hist.last_cmd_rtn is None: hist.last_cmd_rtn = 1 # return code for failure finally: ts1 = ts1 or time.time() self._append_history(inp=src, ts=[ts0, ts1], tee_out=tee.getvalue()) self.accumulated_inputs += src tee.close() self._fix_cwd() if builtins.__xonsh_exit__: # pylint: disable=no-member return True
def _append_history(self, tee_out=None, **info): """Append information about the command to the history. This also handles on_postcommand because this is the place where all the information is available. """ hist = builtins.__xonsh_history__ # pylint: disable=no-member info['rtn'] = hist.last_cmd_rtn if hist is not None else None tee_out = tee_out or None last_out = hist.last_cmd_out if hist is not None else None if last_out is None and tee_out is None: pass elif last_out is None and tee_out is not None: info['out'] = tee_out elif last_out is not None and tee_out is None: info['out'] = last_out else: info['out'] = tee_out + '\n' + last_out events.on_postcommand.fire( cmd=info['inp'], rtn=info['rtn'], out=info.get('out', None), ts=info['ts'] ) if hist is not None: hist.append(info) hist.last_cmd_rtn = hist.last_cmd_out = None def _fix_cwd(self): """Check if the cwd changed out from under us.""" env = builtins.__xonsh_env__ try: cwd = os.getcwd() except (FileNotFoundError, OSError): cwd = None if cwd is None: # directory has been deleted out from under us, most likely pwd = env.get('PWD', None) if pwd is None: # we have no idea where we are env['PWD'] = '<invalid directory>' elif os.path.isdir(pwd): # unclear why os.getcwd() failed. do nothing. pass else: # OK PWD is really gone. msg = '{UNDERLINE_INTENSE_WHITE}{BACKGROUND_INTENSE_BLACK}' msg += "xonsh: working directory does not exist: " + pwd msg += '{NO_COLOR}' self.print_color(msg, file=sys.stderr) elif 'PWD' not in env: # $PWD is missing from env, recreate it env['PWD'] = cwd elif os.path.realpath(cwd) != os.path.realpath(env['PWD']): # The working directory has changed without updating $PWD, fix this old = env['PWD'] env['PWD'] = cwd env['OLDPWD'] = old events.on_chdir.fire(olddir=old, newdir=cwd)
[docs] def push(self, line): """Pushes a line onto the buffer and compiles the code in a way that enables multiline input. """ self.buffer.append(line) if self.need_more_lines: return None, None src = ''.join(self.buffer) src = transform_command(src) return self.compile(src)
[docs] def compile(self, src): """Compiles source code and returns the (possibly modified) source and a valid code object. """ _cache = should_use_cache(self.execer, 'single') if _cache: codefname = code_cache_name(src) cachefname = get_cache_filename(codefname, code=True) usecache, code = code_cache_check(cachefname) if usecache: self.reset_buffer() return src, code lincont = get_line_continuation() if src.endswith(lincont+'\n'): self.need_more_lines = True return src, None try: code = self.execer.compile(src, mode='single', glbs=self.ctx, locs=None) if _cache: update_cache(code, cachefname) self.reset_buffer() except SyntaxError: partial_string_info = check_for_partial_string(src) in_partial_string = (partial_string_info[0] is not None and partial_string_info[1] is None) if (src == '\n' or src.endswith('\n\n')) and not in_partial_string: self.reset_buffer() print_exception() return src, None self.need_more_lines = True code = None except Exception: # pylint: disable=broad-except self.reset_buffer() print_exception() code = None return src, code
[docs] def reset_buffer(self): """Resets the line buffer.""" self.buffer.clear() self.need_more_lines = False self.mlprompt = None
[docs] def settitle(self): """Sets terminal title.""" env = builtins.__xonsh_env__ # pylint: disable=no-member term = env.get('TERM', None) # Shells running in emacs sets TERM to "dumb" or "eterm-color". # Do not set title for these to avoid garbled prompt. if (term is None and not ON_WINDOWS) or term in ['dumb', 'eterm-color', 'linux']: return t = env.get('TITLE') if t is None: return t = self.prompt_formatter(t) if ON_WINDOWS and 'ANSICON' not in env: kernel32.SetConsoleTitleW(t) else: with open(1, 'wb', closefd=False) as f: # prevent xonsh from answering interative questions # on the next command by writing the title f.write("\x1b]0;{0}\x07".format(t).encode()) f.flush()
@property def prompt(self): """Obtains the current prompt string.""" if self.need_more_lines: if self.mlprompt is None: try: self.mlprompt = multiline_prompt() except Exception: # pylint: disable=broad-except print_exception() self.mlprompt = '<multiline prompt error> ' return self.mlprompt env = builtins.__xonsh_env__ # pylint: disable=no-member p = env.get('PROMPT') try: p = self.prompt_formatter(p) except Exception: # pylint: disable=broad-except print_exception() self.settitle() return p
[docs] def format_color(self, string, hide=False, force_string=False, **kwargs): """Formats the colors in a string. This base implmentation colors based on ANSI color codes """ style = builtins.__xonsh_env__.get('XONSH_COLOR_STYLE') return ansi_partial_color_format(string, hide=hide, style=style)
[docs] def print_color(self, string, hide=False, **kwargs): """Prints a string in color. This base implmentation will color based ANSI color codes if a string was given as input. If a list of token pairs is given, it will color based on pygments, if available. If pygments is not available, it will print a colorless string. """ if isinstance(string, str): s = self.format_color(string, hide=hide) elif HAS_PYGMENTS: # assume this is a list of (Token, str) tuples and format it env = builtins.__xonsh_env__ self.styler.style_name = env.get('XONSH_COLOR_STYLE') style_proxy = pyghooks.xonsh_style_proxy(self.styler) formatter = pyghooks.XonshTerminal256Formatter(style=style_proxy) s = pygments.format(string, formatter).rstrip() else: # assume this is a list of (Token, str) tuples and remove color s = ''.join([x for _, x in string]) print(s, **kwargs)
[docs] def color_style_names(self): """Returns an iterable of all available style names.""" return ()
[docs] def color_style(self): """Returns the current color map.""" return {}
[docs] def restore_tty_sanity(self): """An interface for resetting the TTY stdin mode. This is highly dependent on the shell backend. Also it is mostly optional since it only affects ^Z backgrounding behaviour. """ pass