text: ##===-- commandwin.py ----------------------------------------*- Python -*-===##
  ##
  ##                     The LLVM Compiler Infrastructure
  ##
  ## This file is distributed under the University of Illinois Open Source
  ## License. See LICENSE.TXT for details.
  ##
  ##===----------------------------------------------------------------------===##
  
  import cui
  import curses
  import lldb
  from itertools import islice
  
  class History(object):
    def __init__(self):
      self.data = {}
      self.pos = 0
      self.tempEntry = ''
  
    def previous(self, curr):
      if self.pos == len(self.data):
        self.tempEntry = curr
  
      if self.pos < 0:
        return ''
      if self.pos == 0:
        self.pos -= 1
        return ''
      if self.pos > 0:
        self.pos -= 1
        return self.data[self.pos]
  
    def next(self):
      if self.pos < len(self.data):
        self.pos += 1
  
      if self.pos < len(self.data):
        return self.data[self.pos]
      elif self.tempEntry != '':
        return self.tempEntry
      else:
        return ''
  
    def add(self, c):
      self.tempEntry = ''
      self.pos = len(self.data)
      if self.pos == 0 or self.data[self.pos-1] != c:
        self.data[self.pos] = c
        self.pos += 1
  
  class CommandWin(cui.TitledWin):
    def __init__(self, driver, x, y, w, h):
      super(CommandWin, self).__init__(x, y, w, h, "Commands")
      self.command = ""
      self.data = ""
      driver.setSize(w, h)
  
      self.win.scrollok(1)
  
      self.driver = driver
      self.history = History()
  
      def enterCallback(content):
        self.handleCommand(content)
      def tabCompleteCallback(content):
        self.data = content
        matches = lldb.SBStringList()
        commandinterpreter = self.getCommandInterpreter()
        commandinterpreter.HandleCompletion(self.data, self.el.index, 0, -1, matches)
        if matches.GetSize() == 2:
          self.el.content += matches.GetStringAtIndex(0)
          self.el.index = len(self.el.content)
          self.el.draw()
        else:
          self.win.move(self.el.starty, self.el.startx)
          self.win.scroll(1)
          self.win.addstr("Available Completions:")
          self.win.scroll(1)
          for m in islice(matches, 1, None):
            self.win.addstr(self.win.getyx()[0], 0, m)
            self.win.scroll(1)
          self.el.draw()
  
      self.startline = self.win.getmaxyx()[0]-2
  
      self.el = cui.CursesEditLine(self.win, self.history, enterCallback, tabCompleteCallback)
      self.el.prompt = self.driver.getPrompt()
      self.el.showPrompt(self.startline, 0)
  
    def handleCommand(self, cmd):
       # enter!
      self.win.scroll(1) # TODO: scroll more for longer commands
      if cmd == '':
        cmd = self.history.previous('')
      elif cmd in ('q', 'quit'):
        self.driver.terminate()
        return
  
      self.history.add(cmd)
      ret = self.driver.handleCommand(cmd)
      if ret.Succeeded():
        out = ret.GetOutput()
        attr = curses.A_NORMAL
      else:
        out = ret.GetError()
        attr = curses.color_pair(3) # red on black
      self.win.addstr(self.startline, 0, out + '\n', attr)
      self.win.scroll(1)
      self.el.showPrompt(self.startline, 0)
  
    def handleEvent(self, event):
      if isinstance(event, int):
        if event == curses.ascii.EOT and self.el.content == '':
          # When the command is empty, treat CTRL-D as EOF.
          self.driver.terminate()
          return
        self.el.handleEvent(event)
  
    def getCommandInterpreter(self):
      return self.driver.getCommandInterpreter()
  