completion.py: Replace Python fnmatch with libc fnmatch.

This is to reduce our dependency on the Python interpreter.  I just
wrote basic unit tests to prevent trivial regressions.  completion.py
still needs a lot of work.

core/completion.py

@@ -30,7 +30,6 @@
"""

import atexit
import fnmatch
import readline
import os
import sys
@@ -45,6 +44,8 @@
from core import ui
from core import util

import libc

command_e = ast.command_e
value_e = runtime.value_e

@@ -128,7 +129,8 @@ def GetCompleterForName(self, argv0):
      return chain

    for glob_pat, chain in self.patterns:
      if fnmatch.fnmatch(key, glob_pat):
      #log('Matching %r %r', key, glob_pat)
      if libc.fnmatch(glob_pat, key):
        return chain

    return self.lookup['__default__']
@@ -326,7 +328,7 @@ def __init__(self, glob_pat):
    self.glob_pat = glob_pat

  def __call__(self, match):
    return fnmatch.fnmatch(match, self.glob_pat)
    return libc.fnmatch(self.glob_pat, match)


class ChainedCompleter(object):
@@ -363,6 +365,10 @@ def Matches(self, words, index, prefix):
    # Hm actually zsh does something smarter, and which is probably preferable.
    # It completes the word that

  def __str__(self):
    return '<ChainedCompleter %s %s %r %r>' % (
        self.actions, self.predicate, self.prefix, self.suffix)


class DummyParser(object):
  def GetWords(self, buf):

core/completion_test.py

@@ -8,6 +8,7 @@
"""
completion_test.py: Tests for completion.py
"""
from __future__ import print_function

import unittest

@@ -52,9 +53,15 @@ def testLookup(self):
    print(c.GetCompleterForName('/usr/bin/grep'))

    c.RegisterGlob('*.py', C1)
    print(c.GetCompleterForName('/usr/bin/foo.py'))
    comp = c.GetCompleterForName('/usr/bin/foo.py')
    print('py', comp)
    # NOTE: This is an implementation detail
    self.assertEqual(1, len(comp.actions))

    print(c.GetCompleterForName('foo.rb'))
    comp_rb = c.GetCompleterForName('foo.rb')
    print('rb', comp_rb)
    # NOTE: This is an implementation detail
    self.assertEqual(0, len(comp_rb.actions))

  def testWordsAction(self):
    print(list(A1.Matches(['f'], 0, 'f')))
@@ -95,11 +102,13 @@ def testShellFuncExecution(self):
    self.assertEqual(['f1 ', 'f2 '], matches)

  def testChainedCompleter(self):
    print(list(C1.Matches(['f'], 0, 'f')))
    matches = list(C1.Matches(['f'], 0, 'f'))
    self.assertEqual(['foo.py ', 'foo '], matches)

    p = completion.GlobPredicate('*.py')
    c2 = completion.ChainedCompleter([A1], predicate=p)
    print(list(c2.Matches(['f'], 0, 'f')))
    matches = list(c2.Matches(['f'], 0, 'f'))
    self.assertEqual([], matches)

  def testRootCompleter(self):
    comp_lookup = completion.CompletionLookup()