root/trunk/twisted/conch/recvline.py

# -*- test-case-name: twisted.conch.test.test_recvline -*-
# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.

"""
Basic line editing support.

@author: Jp Calderone
"""

import string

from zope.interface import implements

from twisted.conch.insults import insults, helper

from twisted.python import log, reflect

_counters = {}
class Logging(object):
    """Wrapper which logs attribute lookups.

    This was useful in debugging something, I guess.  I forget what.
    It can probably be deleted or moved somewhere more appropriate.
    Nothing special going on here, really.
    """
    def __init__(self, original):
        self.original = original
        key = reflect.qual(original.__class__)
        count = _counters.get(key, 0)
        _counters[key] = count + 1
        self._logFile = file(key + '-' + str(count), 'w')

    def __str__(self):
        return str(super(Logging, self).__getattribute__('original'))

    def __repr__(self):
        return repr(super(Logging, self).__getattribute__('original'))

    def __getattribute__(self, name):
        original = super(Logging, self).__getattribute__('original')
        logFile = super(Logging, self).__getattribute__('_logFile')
        logFile.write(name + '\n')
        return getattr(original, name)

class TransportSequence(object):
    """An L{ITerminalTransport} implementation which forwards calls to
    one or more other L{ITerminalTransport}s.

    This is a cheap way for servers to keep track of the state they
    expect the client to see, since all terminal manipulations can be
    send to the real client and to a terminal emulator that lives in
    the server process.
    """
    implements(insults.ITerminalTransport)

    for keyID in ('UP_ARROW', 'DOWN_ARROW', 'RIGHT_ARROW', 'LEFT_ARROW',
                  'HOME', 'INSERT', 'DELETE', 'END', 'PGUP', 'PGDN',
                  'F1', 'F2', 'F3', 'F4', 'F5', 'F6', 'F7', 'F8', 'F9',
                  'F10', 'F11', 'F12'):
        exec '%s = object()' % (keyID,)

    TAB = '\t'
    BACKSPACE = '\x7f'

    def __init__(self, *transports):
        assert transports, "Cannot construct a TransportSequence with no transports"
        self.transports = transports

    for method in insults.ITerminalTransport:
        exec """\
def %s(self, *a, **kw):
    for tpt in self.transports:
        result = tpt.%s(*a, **kw)
    return result
""" % (method, method)

class LocalTerminalBufferMixin(object):
    """A mixin for RecvLine subclasses which records the state of the terminal.

    This is accomplished by performing all L{ITerminalTransport} operations on both
    the transport passed to makeConnection and an instance of helper.TerminalBuffer.

    @ivar terminalCopy: A L{helper.TerminalBuffer} instance which efforts
    will be made to keep up to date with the actual terminal
    associated with this protocol instance.
    """

    def makeConnection(self, transport):
        self.terminalCopy = helper.TerminalBuffer()
        self.terminalCopy.connectionMade()
        return super(LocalTerminalBufferMixin, self).makeConnection(
            TransportSequence(transport, self.terminalCopy))

    def __str__(self):
        return str(self.terminalCopy)

class RecvLine(insults.TerminalProtocol):
    """L{TerminalProtocol} which adds line editing features.

    Clients will be prompted for lines of input with all the usual
    features: character echoing, left and right arrow support for
    moving the cursor to different areas of the line buffer, backspace
    and delete for removing characters, and insert for toggling
    between typeover and insert mode.  Tabs will be expanded to enough
    spaces to move the cursor to the next tabstop (every four
    characters by default).  Enter causes the line buffer to be
    cleared and the line to be passed to the lineReceived() method
    which, by default, does nothing.  Subclasses are responsible for
    redrawing the input prompt (this will probably change).
    """
    width = 80
    height = 24

    TABSTOP = 4

    ps = ('>>> ', '... ')
    pn = 0
    _printableChars = set(string.printable)

    def connectionMade(self):
        # A list containing the characters making up the current line
        self.lineBuffer = []

        # A zero-based (wtf else?) index into self.lineBuffer.
        # Indicates the current cursor position.
        self.lineBufferIndex = 0

        t = self.terminal
        # A map of keyIDs to bound instance methods.
        self.keyHandlers = {
            t.LEFT_ARROW: self.handle_LEFT,
            t.RIGHT_ARROW: self.handle_RIGHT,
            t.TAB: self.handle_TAB,

            # Both of these should not be necessary, but figuring out
            # which is necessary is a huge hassle.
            '\r': self.handle_RETURN,
            '\n': self.handle_RETURN,

            t.BACKSPACE: self.handle_BACKSPACE,
            t.DELETE: self.handle_DELETE,
            t.INSERT: self.handle_INSERT,
            t.HOME: self.handle_HOME,
            t.END: self.handle_END}

        self.initializeScreen()

    def initializeScreen(self):
        # Hmm, state sucks.  Oh well.
        # For now we will just take over the whole terminal.
        self.terminal.reset()
        self.terminal.write(self.ps[self.pn])
        # XXX Note: I would prefer to default to starting in insert
        # mode, however this does not seem to actually work!  I do not
        # know why.  This is probably of interest to implementors
        # subclassing RecvLine.

        # XXX XXX Note: But the unit tests all expect the initial mode
        # to be insert right now.  Fuck, there needs to be a way to
        # query the current mode or something.
        # self.setTypeoverMode()
        self.setInsertMode()

    def currentLineBuffer(self):
        s = ''.join(self.lineBuffer)
        return s[:self.lineBufferIndex], s[self.lineBufferIndex:]

    def setInsertMode(self):
        self.mode = 'insert'
        self.terminal.setModes([insults.modes.IRM])

    def setTypeoverMode(self):
        self.mode = 'typeover'
        self.terminal.resetModes([insults.modes.IRM])

    def drawInputLine(self):
        """
        Write a line containing the current input prompt and the current line
        buffer at the current cursor position.
        """
        self.terminal.write(self.ps[self.pn] + ''.join(self.lineBuffer))

    def terminalSize(self, width, height):
        # XXX - Clear the previous input line, redraw it at the new
        # cursor position
        self.terminal.eraseDisplay()
        self.terminal.cursorHome()
        self.width = width
        self.height = height
        self.drawInputLine()

    def unhandledControlSequence(self, seq):
        pass

    def keystrokeReceived(self, keyID, modifier):
        m = self.keyHandlers.get(keyID)
        if m is not None:
            m()
        elif keyID in self._printableChars:
            self.characterReceived(keyID, False)
        else:
            log.msg("Received unhandled keyID: %r" % (keyID,))

    def characterReceived(self, ch, moreCharactersComing):
        if self.mode == 'insert':
            self.lineBuffer.insert(self.lineBufferIndex, ch)
        else:
            self.lineBuffer[self.lineBufferIndex:self.lineBufferIndex+1] = [ch]
        self.lineBufferIndex += 1
        self.terminal.write(ch)

    def handle_TAB(self):
        n = self.TABSTOP - (len(self.lineBuffer) % self.TABSTOP)
        self.terminal.cursorForward(n)
        self.lineBufferIndex += n
        self.lineBuffer.extend(' ' * n)

    def handle_LEFT(self):
        if self.lineBufferIndex > 0:
            self.lineBufferIndex -= 1
            self.terminal.cursorBackward()

    def handle_RIGHT(self):
        if self.lineBufferIndex < len(self.lineBuffer):
            self.lineBufferIndex += 1
            self.terminal.cursorForward()

    def handle_HOME(self):
        if self.lineBufferIndex:
            self.terminal.cursorBackward(self.lineBufferIndex)
            self.lineBufferIndex = 0

    def handle_END(self):
        offset = len(self.lineBuffer) - self.lineBufferIndex
        if offset:
            self.terminal.cursorForward(offset)
            self.lineBufferIndex = len(self.lineBuffer)

    def handle_BACKSPACE(self):
        if self.lineBufferIndex > 0:
            self.lineBufferIndex -= 1
            del self.lineBuffer[self.lineBufferIndex]
            self.terminal.cursorBackward()
            self.terminal.deleteCharacter()

    def handle_DELETE(self):
        if self.lineBufferIndex < len(self.lineBuffer):
            del self.lineBuffer[self.lineBufferIndex]
            self.terminal.deleteCharacter()

    def handle_RETURN(self):
        line = ''.join(self.lineBuffer)
        self.lineBuffer = []
        self.lineBufferIndex = 0
        self.terminal.nextLine()
        self.lineReceived(line)

    def handle_INSERT(self):
        assert self.mode in ('typeover', 'insert')
        if self.mode == 'typeover':
            self.setInsertMode()
        else:
            self.setTypeoverMode()

    def lineReceived(self, line):
        pass

class HistoricRecvLine(RecvLine):
    """L{TerminalProtocol} which adds both basic line-editing features and input history.

    Everything supported by L{RecvLine} is also supported by this class.  In addition, the
    up and down arrows traverse the input history.  Each received line is automatically
    added to the end of the input history.
    """
    def connectionMade(self):
        RecvLine.connectionMade(self)

        self.historyLines = []
        self.historyPosition = 0

        t = self.terminal
        self.keyHandlers.update({t.UP_ARROW: self.handle_UP,
                                 t.DOWN_ARROW: self.handle_DOWN})

    def currentHistoryBuffer(self):
        b = tuple(self.historyLines)
        return b[:self.historyPosition], b[self.historyPosition:]

    def _deliverBuffer(self, buf):
        if buf:
            for ch in buf[:-1]:
                self.characterReceived(ch, True)
            self.characterReceived(buf[-1], False)

    def handle_UP(self):
        if self.lineBuffer and self.historyPosition == len(self.historyLines):
            self.historyLines.append(self.lineBuffer)
        if self.historyPosition > 0:
            self.handle_HOME()
            self.terminal.eraseToLineEnd()

            self.historyPosition -= 1
            self.lineBuffer = []

            self._deliverBuffer(self.historyLines[self.historyPosition])

    def handle_DOWN(self):
        if self.historyPosition < len(self.historyLines) - 1:
            self.handle_HOME()
            self.terminal.eraseToLineEnd()

            self.historyPosition += 1
            self.lineBuffer = []

            self._deliverBuffer(self.historyLines[self.historyPosition])
        else:
            self.handle_HOME()
            self.terminal.eraseToLineEnd()

            self.historyPosition = len(self.historyLines)
            self.lineBuffer = []
            self.lineBufferIndex = 0

    def handle_RETURN(self):
        if self.lineBuffer:
            self.historyLines.append(''.join(self.lineBuffer))
        self.historyPosition = len(self.historyLines)
        return RecvLine.handle_RETURN(self)