Add third_party/pexpect

third_party/pexpect/pexpect/replwrap.py

Index: third_party/pexpect/pexpect/replwrap.py
diff --git a/third_party/pexpect/pexpect/replwrap.py b/third_party/pexpect/pexpect/replwrap.py
new file mode 100644
index 0000000000000000000000000000000000000000..6439b35cbf22f9d63a587ad47ae355fed60f33ce
--- /dev/null
+++ b/third_party/pexpect/pexpect/replwrap.py
@@ -0,0 +1,113 @@
+"""Generic wrapper for read-eval-print-loops, a.k.a. interactive shells
+"""
+import os.path
+import signal
+import sys
+
+import pexpect
+
+PY3 = (sys.version_info[0] >= 3)
+
+if PY3:
+    basestring = str
+
+PEXPECT_PROMPT = u'[PEXPECT_PROMPT>'
+PEXPECT_CONTINUATION_PROMPT = u'[PEXPECT_PROMPT+'
+
+class REPLWrapper(object):
+    """Wrapper for a REPL.
+
+    :param cmd_or_spawn: This can either be an instance of :class:`pexpect.spawn`
+      in which a REPL has already been started, or a str command to start a new
+      REPL process.
+    :param str orig_prompt: The prompt to expect at first.
+    :param str prompt_change: A command to change the prompt to something more
+      unique. If this is ``None``, the prompt will not be changed. This will
+      be formatted with the new and continuation prompts as positional
+      parameters, so you can use ``{}`` style formatting to insert them into
+      the command.
+    :param str new_prompt: The more unique prompt to expect after the change.
+    :param str extra_init_cmd: Commands to do extra initialisation, such as
+      disabling pagers.
+    """
+    def __init__(self, cmd_or_spawn, orig_prompt, prompt_change,
+                 new_prompt=PEXPECT_PROMPT,
+                 continuation_prompt=PEXPECT_CONTINUATION_PROMPT,
+                 extra_init_cmd=None):
+        if isinstance(cmd_or_spawn, basestring):
+            self.child = pexpect.spawn(cmd_or_spawn, echo=False, encoding='utf-8')
+        else:
+            self.child = cmd_or_spawn
+        if self.child.echo:
+            # Existing spawn instance has echo enabled, disable it
+            # to prevent our input from being repeated to output.
+            self.child.setecho(False)
+            self.child.waitnoecho()
+
+        if prompt_change is None:
+            self.prompt = orig_prompt
+        else:
+            self.set_prompt(orig_prompt,
+                        prompt_change.format(new_prompt, continuation_prompt))
+            self.prompt = new_prompt
+        self.continuation_prompt = continuation_prompt
+
+        self._expect_prompt()
+
+        if extra_init_cmd is not None:
+            self.run_command(extra_init_cmd)
+
+    def set_prompt(self, orig_prompt, prompt_change):
+        self.child.expect(orig_prompt)
+        self.child.sendline(prompt_change)
+
+    def _expect_prompt(self, timeout=-1):
+        return self.child.expect_exact([self.prompt, self.continuation_prompt],
+                                       timeout=timeout)
+
+    def run_command(self, command, timeout=-1):
+        """Send a command to the REPL, wait for and return output.
+
+        :param str command: The command to send. Trailing newlines are not needed.
+          This should be a complete block of input that will trigger execution;
+          if a continuation prompt is found after sending input, :exc:`ValueError`
+          will be raised.
+        :param int timeout: How long to wait for the next prompt. -1 means the
+          default from the :class:`pexpect.spawn` object (default 30 seconds).
+          None means to wait indefinitely.
+        """
+        # Split up multiline commands and feed them in bit-by-bit
+        cmdlines = command.splitlines()
+        # splitlines ignores trailing newlines - add it back in manually
+        if command.endswith('\n'):
+            cmdlines.append('')
+        if not cmdlines:
+            raise ValueError("No command was given")
+
+        res = []
+        self.child.sendline(cmdlines[0])
+        for line in cmdlines[1:]:
+            self._expect_prompt(timeout=timeout)
+            res.append(self.child.before)
+            self.child.sendline(line)
+
+        # Command was fully submitted, now wait for the next prompt
+        if self._expect_prompt(timeout=timeout) == 1:
+            # We got the continuation prompt - command was incomplete
+            self.child.kill(signal.SIGINT)
+            self._expect_prompt(timeout=1)
+            raise ValueError("Continuation prompt found - input was incomplete:\n"
+                             + command)
+        return u''.join(res + [self.child.before])
+
+def python(command="python"):
+    """Start a Python shell and return a :class:`REPLWrapper` object."""
+    return REPLWrapper(command, u">>> ", u"import sys; sys.ps1={0!r}; sys.ps2={1!r}")
+
+def bash(command="bash"):
+    """Start a bash shell and return a :class:`REPLWrapper` object."""
+    bashrc = os.path.join(os.path.dirname(__file__), 'bashrc.sh')
+    child = pexpect.spawn(command, ['--rcfile', bashrc], echo=False,
+                          encoding='utf-8')
+    return REPLWrapper(child, u'\$', u"PS1='{0}' PS2='{1}' PROMPT_COMMAND=''",
+                       extra_init_cmd="export PAGER=cat")