lldb/third_party/Python/module/pexpect-4.6/pexpect/replwrap.py

   1 """Generic wrapper for read-eval-print-loops, a.k.a. interactive shells
   2 """
   3 import os.path
   4 import signal
   5 import sys
   6
   7 import pexpect
   8
   9 PY3 = (sys.version_info[0] >= 3)
  10
  11 if PY3:
  12     basestring = str
  13
  14 PEXPECT_PROMPT = u'[PEXPECT_PROMPT>'
  15 PEXPECT_CONTINUATION_PROMPT = u'[PEXPECT_PROMPT+'
  16
  17 class REPLWrapper(object):
  18     """Wrapper for a REPL.
  19
  20     :param cmd_or_spawn: This can either be an instance of :class:`pexpect.spawn`
  21       in which a REPL has already been started, or a str command to start a new
  22       REPL process.
  23     :param str orig_prompt: The prompt to expect at first.
  24     :param str prompt_change: A command to change the prompt to something more
  25       unique. If this is ``None``, the prompt will not be changed. This will
  26       be formatted with the new and continuation prompts as positional
  27       parameters, so you can use ``{}`` style formatting to insert them into
  28       the command.
  29     :param str new_prompt: The more unique prompt to expect after the change.
  30     :param str extra_init_cmd: Commands to do extra initialisation, such as
  31       disabling pagers.
  32     """
  33     def __init__(self, cmd_or_spawn, orig_prompt, prompt_change,
  34                  new_prompt=PEXPECT_PROMPT,
  35                  continuation_prompt=PEXPECT_CONTINUATION_PROMPT,
  36                  extra_init_cmd=None):
  37         if isinstance(cmd_or_spawn, basestring):
  38             self.child = pexpect.spawn(cmd_or_spawn, echo=False, encoding='utf-8')
  39         else:
  40             self.child = cmd_or_spawn
  41         if self.child.echo:
  42             # Existing spawn instance has echo enabled, disable it
  43             # to prevent our input from being repeated to output.
  44             self.child.setecho(False)
  45             self.child.waitnoecho()
  46
  47         if prompt_change is None:
  48             self.prompt = orig_prompt
  49         else:
  50             self.set_prompt(orig_prompt,
  51                         prompt_change.format(new_prompt, continuation_prompt))
  52             self.prompt = new_prompt
  53         self.continuation_prompt = continuation_prompt
  54
  55         self._expect_prompt()
  56
  57         if extra_init_cmd is not None:
  58             self.run_command(extra_init_cmd)
  59
  60     def set_prompt(self, orig_prompt, prompt_change):
  61         self.child.expect(orig_prompt)
  62         self.child.sendline(prompt_change)
  63
  64     def _expect_prompt(self, timeout=-1):
  65         return self.child.expect_exact([self.prompt, self.continuation_prompt],
  66                                        timeout=timeout)
  67
  68     def run_command(self, command, timeout=-1):
  69         """Send a command to the REPL, wait for and return output.
  70
  71         :param str command: The command to send. Trailing newlines are not needed.
  72           This should be a complete block of input that will trigger execution;
  73           if a continuation prompt is found after sending input, :exc:`ValueError`
  74           will be raised.
  75         :param int timeout: How long to wait for the next prompt. -1 means the
  76           default from the :class:`pexpect.spawn` object (default 30 seconds).
  77           None means to wait indefinitely.
  78         """
  79         # Split up multiline commands and feed them in bit-by-bit
  80         cmdlines = command.splitlines()
  81         # splitlines ignores trailing newlines - add it back in manually
  82         if command.endswith('\n'):
  83             cmdlines.append('')
  84         if not cmdlines:
  85             raise ValueError("No command was given")
  86
  87         res = []
  88         self.child.sendline(cmdlines[0])
  89         for line in cmdlines[1:]:
  90             self._expect_prompt(timeout=timeout)
  91             res.append(self.child.before)
  92             self.child.sendline(line)
  93
  94         # Command was fully submitted, now wait for the next prompt
  95         if self._expect_prompt(timeout=timeout) == 1:
  96             # We got the continuation prompt - command was incomplete
  97             self.child.kill(signal.SIGINT)
  98             self._expect_prompt(timeout=1)
  99             raise ValueError("Continuation prompt found - input was incomplete:\n"
 100                              + command)
 101         return u''.join(res + [self.child.before])
 102
 103 def python(command="python"):
 104     """Start a Python shell and return a :class:`REPLWrapper` object."""
 105     return REPLWrapper(command, u">>> ", u"import sys; sys.ps1={0!r}; sys.ps2={1!r}")
 106
 107 def bash(command="bash"):
 108     """Start a bash shell and return a :class:`REPLWrapper` object."""
 109     bashrc = os.path.join(os.path.dirname(__file__), 'bashrc.sh')
 110     child = pexpect.spawn(command, ['--rcfile', bashrc], echo=False,
 111                           encoding='utf-8')
 112
 113     # If the user runs 'env', the value of PS1 will be in the output. To avoid
 114     # replwrap seeing that as the next prompt, we'll embed the marker characters
 115     # for invisible characters in the prompt; these show up when inspecting the
 116     # environment variable, but not when bash displays the prompt.
 117     ps1 = PEXPECT_PROMPT[:5] + u'\\[\\]' + PEXPECT_PROMPT[5:]
 118     ps2 = PEXPECT_CONTINUATION_PROMPT[:5] + u'\\[\\]' + PEXPECT_CONTINUATION_PROMPT[5:]
 119     prompt_change = u"PS1='{0}' PS2='{1}' PROMPT_COMMAND=''".format(ps1, ps2)
 120
 121     return REPLWrapper(child, u'\\$', prompt_change,
 122                        extra_init_cmd="export PAGER=cat")