[Slackware] What's new in /etc ?

#!/usr/bin/python
# -*- coding: UTF-8 -*-

import sys
import os
import stat
import glob
import difflib
import string
import subprocess

from PyQt4 import QtGui, QtCore

from pygments import highlight
from pygments.lexers import DiffLexer
from pygments.formatters import HtmlFormatter

CWD = os.getcwd()
EDITOR = 'gvim -f'
PATCH = 'patch -p0'
DIR = '/etc'

def usage():
    print "Usage: %s directory" % sys.argv[0]


# find all *.new files in /etc
def findnew (top = '.', depthfirst = True):
    os.chdir(top)
    names = glob.glob('*.new')
    if not depthfirst:
        yield top, names
    for name in names:
        try:
            st = os.lstat(os.path.join(top, name))
        except os.error:
            continue
        if stat.S_ISDIR(st.st_mode):
            for (newtop, children) in findnew (os.path.join(top, name), depthfirst):
                yield newtop, children
    if depthfirst:
        yield top, names


class MainWindow(QtGui.QWidget):
    newlist = None # QListWidget
    diff    = None # QTextEdit
    edit    = None # QPushButton
    accept  = None # QPushButton
    reject  = None # QPushButton
    patch   = None # QPushButton

    newfile = None # /etc/file.new
    oldfile = None # /etc/file

    @QtCore.pyqtSlot()
    def on_partial_diff(self):
        cursor = self.diff.textCursor()
        start  = cursor.selectionStart()
        end    = cursor.selectionEnd()

        # starting and ending line numbers for the selection
        start_line = self.diff.document().findBlock(start).firstLineNumber()
        end_line   = self.diff.document().findBlock(end).firstLineNumber()

        fulldiff  = self.diff.toPlainText().split('\n');
        max_lines = len(fulldiff) - 1

        # two first lines
        partdiff = fulldiff[0] + '\n' + fulldiff[1] + '\n'
        
        # looking for start of diff block (@@ -16,7 +16,7 @@)
        if start_line < 2:
            start_line = 2
        else:
            while fulldiff[start_line][0:2] != '@@':
                start_line = start_line - 1

        # looking for end of diff block (next @@ ... @@ or EOF)
        if end_line <= start_line:
            end_line = start_line + 1
        
        while end_line < max_lines:
            if fulldiff[end_line][0:2] == '@@':
                break
            end_line = end_line + 1
        
        for l in range(start_line, end_line):
            partdiff = partdiff + fulldiff[l] + '\n'
      
        # apply partial patch
        pipe = subprocess.Popen(PATCH, shell=True, stdin=subprocess.PIPE)
        pipe.stdin.writelines(partdiff)
        pipe.stdin.close()
        
        self.reloaddiff(self.newfile)

    def enable_buttons(self):
        n = self.newlist.count()
        self.edit.setEnabled(n > 0)
        self.accept.setEnabled(n > 0)
        self.reject.setEnabled(n > 0)


    @QtCore.pyqtSlot()
    def on_selection_changed(self):
        self.patch.setEnabled(
                self.diff.textCursor().selectionStart() != self.diff.textCursor().selectionEnd()
                )
        

    @QtCore.pyqtSlot()
    def on_accept(self):
        os.rename(self.newfile, self.oldfile)
        self.newlist.takeItem(self.newlist.currentRow())
        self.enable_buttons()

    @QtCore.pyqtSlot()
    def on_reject(self):
        os.remove(self.newfile)
        self.newlist.takeItem(self.newlist.currentRow())
        self.enable_buttons()

    @QtCore.pyqtSlot()
    def on_edit(self):
        self.accept.setEnabled(False)
        self.newlist.setEnabled(False)

        p = subprocess.Popen(EDITOR + ' ' + self.oldfile, shell=True)
        sts = os.waitpid(p.pid, 0)

        self.reloaddiff(self.newfile)
        self.newlist.setEnabled(True)
        self.accept.setEnabled(True)

    @QtCore.pyqtSlot(QtCore.QString)
    def reloaddiff(self, newfile):
        self.diff.clear()
        self.newfile = str(newfile)
        self.oldfile = self.newfile[0:self.newfile.find('.new')]
        if self.newfile:
            tolines    = open(self.newfile, 'U').readlines()
            fromlines  = open(self.oldfile, 'U').readlines()
            difflines  = difflib.unified_diff(fromlines, tolines, self.oldfile, self.newfile)
            difftext   = string.join(difflines, '')

            self.edit.setToolTip(EDITOR + ' ' + self.oldfile)
            self.reject.setToolTip('Remove ' + self.newfile)
            self.accept.setToolTip(self.newfile + ' -> ' + self.oldfile)
            self.accept.setEnabled(bool(difftext))

            colored_rtf  = highlight(difftext, DiffLexer(), HtmlFormatter(full=True))
            self.diff.setText(colored_rtf)

    def __init__(self, parent=None):
        QtGui.QWidget.__init__(self, parent)

        mvbox  = QtGui.QVBoxLayout() # main layout
        split  = QtGui.QSplitter(QtCore.Qt.Horizontal, self) # left-right splitter
        
        rpart  = QtGui.QWidget(split) # right side
        lpart  = QtGui.QWidget(split) # left side

        rvbox  = QtGui.QVBoxLayout() # right side layout
        lvbox  = QtGui.QVBoxLayout() # left side layout
        rpart.setLayout(rvbox)
        lpart.setLayout(lvbox)

        self.diff = QtGui.QTextEdit() # to show diff
        self.diff.setReadOnly(True)
       
        self.newlist = QtGui.QListWidget() # to show all *.new files
       # Load all *.new files  
        for (basepath, children) in findnew(DIR):
            for child in children:
                self.newlist.addItem(os.path.join(basepath, child))
        os.chdir(CWD)
        
        quit        = QtGui.QPushButton('&Quit', self)
        self.accept = QtGui.QPushButton('&Accept', self)
        self.reject = QtGui.QPushButton('&Reject', self)
        self.edit   = QtGui.QPushButton('&Edit old...', self)
        self.patch  = QtGui.QPushButton('A&pply selection', self)
        self.patch.setEnabled(False)
        self.patch.setToolTip('Patch using block with selected text')

        lvbox.addWidget(self.diff) # diff is on the left side
        lvbox.addWidget(self.patch) # "apply patch" button (can be invisible)
        buttons = QtGui.QHBoxLayout() # buttons are below it
        lvbox.addLayout(buttons) # buttons layout
        buttons.addWidget(self.accept)
        buttons.addWidget(self.reject)
        buttons.addWidget(self.edit)

        rvbox.addWidget(self.newlist) # file list is on the right side
        rvbox.addWidget(quit) # quit button is below it

        mvbox.addWidget(split) # split is the main widget of main window
        split.addWidget(lpart) # add the left side on the split
        split.addWidget(rpart) # add the right side on the split

        self.resize(640, 480)
        self.setWindowTitle("What\'s new in %s ?" % DIR)
        self.setLayout(mvbox)

        self.connect(quit, QtCore.SIGNAL('clicked()'), QtGui.qApp, QtCore.SLOT('quit()'))
        self.connect(self.edit, QtCore.SIGNAL('clicked()'), self, QtCore.SLOT('on_edit()'))
        self.connect(self.accept, QtCore.SIGNAL('clicked()'), self, QtCore.SLOT('on_accept()'))
        self.connect(self.reject, QtCore.SIGNAL('clicked()'), self, QtCore.SLOT('on_reject()'))
        self.connect(self.diff, QtCore.SIGNAL('selectionChanged()'), self, QtCore.SLOT('on_selection_changed()'))
        self.connect(self.newlist, QtCore.SIGNAL('currentTextChanged(QString)'),
                             self, QtCore.SLOT('reloaddiff(QString)'))
        
        self.newlist.setCurrentRow(0)
        self.enable_buttons()


if len(sys.argv) > 2:
    usage()
    sys.exit(1)
elif len(sys.argv) == 2:
    DIR = sys.argv[1]


app = QtGui.QApplication(sys.argv)
win = MainWindow()
win.show()

sys.exit(app.exec_())