bash/bbs/utils/menu.py

   1 #!/usr/bin/python
   2 """Yet another curses-based directory tree browser, in Python.
   3
   4 I thought I could use something like this for filename entry, kind of
   5 like the old 4DOS 'select' command --- cd $(cursoutline.py).  So you
   6 navigate and hit Enter, and it exits and spits out the file you're on.
   7
   8 """
   9 # There are several general approaches to the drawing-an-outline
  10 # problem.  This program supports the following operations:
  11 # - move cursor to previous item (in preorder traversal)
  12 # - move cursor to next item (likewise)
  13 # - hide descendants
  14 # - reveal children
  15 # And because it runs over the filesystem, it must be at least somewhat lazy
  16 # about expanding children.
  17 # And it doesn't really bother to worry about someone else changing the outline
  18 # behind its back.
  19 # So the strategy is to store our current linear position in the
  20 # inorder traversal, and defer operations on the current node until the next
  21 # time we're traversing.
  22
  23
  24 import curses.wrapper, time, random, cgitb, os, sys
  25 cgitb.enable(format="text")
  26 ESC = 27
  27 result = ''
  28 start = '.'
  29
  30 def pad(data, width):
  31     # XXX this won't work with UTF-8
  32     return data + ' ' * (width - len(data))
  33
  34 class File:
  35     def __init__(self, name):
  36         self.name = name
  37     def render(self, depth, width):
  38         return pad('%s%s %s' % (' ' * 4 * depth, self.icon(),
  39                                 os.path.basename(self.name)), width)
  40     def icon(self): return '   '
  41     def traverse(self): yield self, 0
  42     def expand(self): pass
  43     def collapse(self): pass
  44
  45 class Dir(File):
  46     def __init__(self, name):
  47         File.__init__(self, name)
  48         try: self.kidnames = os.listdir(name)
  49         except: self.kidnames = None  # probably permission denied
  50         self.kids = None
  51         self.expanded = False
  52     def children(self):
  53         if self.kidnames is None: return []
  54         if self.kids is None:
  55             self.kids = [factory(os.path.join(self.name, kid))
  56                          for kid in self.kidnames]
  57         return self.kids
  58     def icon(self):
  59         if self.expanded: return '[-]'
  60         elif self.kidnames is None: return '[?]'
  61         elif self.children(): return '[+]'
  62         else: return '[ ]'
  63     def expand(self): self.expanded = True
  64     def collapse(self): self.expanded = False
  65     def traverse(self):
  66         yield self, 0
  67         if not self.expanded: return
  68         for child in self.children():
  69             for kid, depth in child.traverse():
  70                 yield kid, depth + 1
  71
  72 def factory(name):
  73     if os.path.isdir(name): return Dir(name)
  74     else: return File(name)
  75
  76 def main(stdscr):
  77     cargo_cult_routine(stdscr)
  78     stdscr.nodelay(0)
  79     mydir = factory(start)
  80     mydir.expand()
  81     curidx = 3
  82     pending_action = None
  83     pending_save = False
  84
  85     while 1:
  86         stdscr.clear()
  87         curses.init_pair(1, curses.COLOR_WHITE, curses.COLOR_BLUE)
  88         line = 0
  89         offset = max(0, curidx - curses.LINES + 3)
  90         for data, depth in mydir.traverse():
  91             if line == curidx:
  92                 stdscr.attrset(curses.color_pair(1) | curses.A_BOLD)
  93                 if pending_action:
  94                     getattr(data, pending_action)()
  95                     pending_action = None
  96                 elif pending_save:
  97                     global result
  98                     result = data.name
  99                     return
 100             else:
 101                 stdscr.attrset(curses.color_pair(0))
 102             if 0 <= line - offset < curses.LINES - 1:
 103                 stdscr.addstr(line - offset, 0,
 104                               data.render(depth, curses.COLS))
 105             line += 1
 106         stdscr.refresh()
 107         ch = stdscr.getch()
 108         if ch == curses.KEY_UP: curidx -= 1
 109         elif ch == curses.KEY_DOWN: curidx += 1
 110         elif ch == curses.KEY_PPAGE:
 111             curidx -= curses.LINES
 112             if curidx < 0: curidx = 0
 113         elif ch == curses.KEY_NPAGE:
 114             curidx += curses.LINES
 115             if curidx >= line: curidx = line - 1
 116         elif ch == curses.KEY_RIGHT: pending_action = 'expand'
 117         elif ch == curses.KEY_LEFT: pending_action = 'collapse'
 118         elif ch == ESC: return
 119         elif ch == ord('\n'): pending_save = True
 120         curidx %= line
 121
 122 def cargo_cult_routine(win):
 123     win.clear()
 124     win.refresh()
 125     curses.nl()
 126     curses.noecho()
 127     win.timeout(0)
 128
 129 def open_tty():
 130     saved_stdin = os.dup(0)
 131     saved_stdout = os.dup(1)
 132     os.close(0)
 133     os.close(1)
 134     stdin = os.open('/dev/tty', os.O_RDONLY)
 135     stdout = os.open('/dev/tty', os.O_RDWR)
 136     return saved_stdin, saved_stdout
 137
 138 def restore_stdio((saved_stdin, saved_stdout)):
 139     os.close(0)
 140     os.close(1)
 141     os.dup(saved_stdin)
 142     os.dup(saved_stdout)
 143
 144 if __name__ == '__main__':
 145     global start
 146     if len(sys.argv) > 1:
 147         start = sys.argv[1]
 148     saved_fds = open_tty()
 149     try: curses.wrapper(main)
 150     finally: restore_stdio(saved_fds)
 151     print result
 152