browse.py

#!/usr/bin/python
#
# Urwid example lazy directory browser / tree view
#    Original version:
#      Copyright (C) 2004-2010  Ian Ward
#    Modified by Rob Lanphier to use general TreeWidget/TreeWalker classes
#
#    This library is free software; you can redistribute it and/or
#    modify it under the terms of the GNU Lesser General Public
#    License as published by the Free Software Foundation; either
#    version 2.1 of the License, or (at your option) any later version.
#
#    This library is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
#    Lesser General Public License for more details.
#
#    You should have received a copy of the GNU Lesser General Public
#    License along with this library; if not, write to the Free Software
#    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
# Urwid web site: http://excess.org/urwid/

"""
Urwid example lazy directory browser / tree view

Features:
- custom selectable widgets for files and directories
- custom message widgets to identify access errors and empty directories
- custom list walker for displaying widgets in a tree fashion
- outputs a quoted list of files and directories "selected" on exit
"""

import os

import urwid


class FlagFileWidget(urwid.TreeWidget):
    # apply an attribute to the expand/unexpand icons
    unexpanded_icon = urwid.AttrMap(urwid.TreeWidget.unexpanded_icon,
        'dirmark')
    expanded_icon = urwid.AttrMap(urwid.TreeWidget.expanded_icon,
        'dirmark')

    def __init__(self, node):
        self.__super.__init__(node)
        # insert an extra AttrWrap for our own use
        self._w = urwid.AttrWrap(self._w, None)
        self.flagged = False
        self.update_w()

    def selectable(self):
        return True

    def keypress(self, size, key):
        """allow subclasses to intercept keystrokes"""
        key = self.__super.keypress(size, key)
        if key:
            key = self.unhandled_keys(size, key)
        return key

    def unhandled_keys(self, size, key):
        """
        Override this method to intercept keystrokes in subclasses.
        Default behavior: Toggle flagged on space, ignore other keys.
        """
        if key == " ":
            self.flagged = not self.flagged
            self.update_w()
        else:
            return key

    def update_w(self):
        """Update the attributes of self.widget based on self.flagged.
        """
        if self.flagged:
            self._w.attr = 'flagged'
            self._w.focus_attr = 'flagged focus'
        else:
            self._w.attr = 'body'
            self._w.focus_attr = 'focus'


class FileTreeWidget(FlagFileWidget):
    """Widget for individual files."""
    def __init__(self, node):
        self.__super.__init__(node)
        path = node.get_value()
        add_widget(path, self)

    def get_display_text(self):
        return self.get_node().get_key()
    


class EmptyWidget(urwid.TreeWidget):
    """A marker for expanded directories with no contents."""
    def get_display_text(self):
        return ('flag', '(empty directory)')


class ErrorWidget(urwid.TreeWidget):
    """A marker for errors reading directories."""

    def get_display_text(self):
        return ('error', "(error/permission denied)")


class DirectoryWidget(FlagFileWidget):
    """Widget for a directory."""
    def __init__(self, node):
        self.__super.__init__(node)
        path = node.get_value()
        add_widget(path, self)
        self.expanded = starts_expanded(path)
        self.update_expanded_icon()

    def get_display_text(self):
        node = self.get_node()
        if node.get_depth() == 0:
            return "/"
        else:
            return node.get_key()


class FileNode(urwid.TreeNode):
    """Metadata storage for individual files"""

    def __init__(self, path, parent=None):
        depth = path.count(dir_sep())
        key = os.path.basename(path)
        urwid.TreeNode.__init__(self, path, key=key, parent=parent, depth=depth)

    def load_parent(self):
        parentname, myname = os.path.split(self.get_value())
        parent = DirectoryNode(parentname)
        parent.set_child_node(self.get_key(), self)
        return parent

    def load_widget(self):
        return FileTreeWidget(self)


class EmptyNode(urwid.TreeNode):
    def load_widget(self):
        return EmptyWidget(self)


class ErrorNode(urwid.TreeNode):
    def load_widget(self):
        return ErrorWidget(self)


class DirectoryNode(urwid.ParentNode):
    """Metadata storage for directories"""

    def __init__(self, path, parent=None):
        if path == dir_sep():
            depth = 0
            key = None
        else:
            depth = path.count(dir_sep())
            key = os.path.basename(path)
        urwid.ParentNode.__init__(self, path, key=key, parent=parent, 
                                  depth=depth)

    def load_parent(self):
        parentname, myname = os.path.split(self.get_value())
        parent = DirectoryNode(parentname)
        parent.set_child_node(self.get_key(), self)
        return parent

    def load_child_keys(self):
        dirs = []
        files = []
        try:
            path = self.get_value()
            # separate dirs and files
            for a in os.listdir(path):
                if os.path.isdir(os.path.join(path,a)):
                    dirs.append(a)
                else:
                    files.append(a)
        except OSError, e:
            depth = self.get_depth() + 1
            self._children[None] = ErrorNode(self, parent=self, key=None, 
                                             depth=depth)
            return [None]

        # sort dirs and files
        dirs.sort(sensible_cmp)
        files.sort(sensible_cmp)
        # store where the first file starts
        self.dir_count = len(dirs)
        # collect dirs and files together again
        keys = dirs + files
        if len(keys) == 0:
            depth=self.get_depth() + 1
            self._children[None] = EmptyNode(self, parent=self, key=None, 
                                             depth=depth)
            keys = [None]
        return keys

    def load_child_node(self, key):
        """Return either a FileNode or DirectoryNode"""
        index = self.get_child_index(key)
        if key is None:
            return EmptyNode(None)
        else:
            path = os.path.join(self.get_value(), key)
            if index < self.dir_count:
                return DirectoryNode(path, parent=self)
            else:
                path = os.path.join(self.get_value(), key)
                return FileNode(path, parent=self)

    def load_widget(self):
        return DirectoryWidget(self)


class DirectoryBrowser:
    palette = [
        ('body', 'black', 'light gray'),
        ('flagged', 'black', 'dark green', ('bold','underline')),
        ('focus', 'light gray', 'dark blue', 'standout'),
        ('flagged focus', 'yellow', 'dark cyan', 
                ('bold','standout','underline')),
        ('head', 'yellow', 'black', 'standout'),
        ('foot', 'light gray', 'black'),
        ('key', 'light cyan', 'black','underline'),
        ('title', 'white', 'black', 'bold'),
        ('dirmark', 'black', 'dark cyan', 'bold'),
        ('flag', 'dark gray', 'light gray'),
        ('error', 'dark red', 'light gray'),
        ]
    
    footer_text = [
        ('title', "Directory Browser"), "    ",
        ('key', "UP"), ",", ('key', "DOWN"), ",",
        ('key', "PAGE UP"), ",", ('key', "PAGE DOWN"),
        "  ",
        ('key', "SPACE"), "  ",
        ('key', "+"), ",",
        ('key', "-"), "  ",
        ('key', "LEFT"), "  ",
        ('key', "HOME"), "  ", 
        ('key', "END"), "  ",
        ('key', "Q"),
        ]
    
    
    def __init__(self):
        cwd = os.getcwd()
        store_initial_cwd(cwd)
        self.header = urwid.Text("")
        self.listbox = urwid.TreeListBox(urwid.TreeWalker(DirectoryNode(cwd)))
        self.listbox.offset_rows = 1
        self.footer = urwid.AttrWrap(urwid.Text(self.footer_text),
            'foot')
        self.view = urwid.Frame(
            urwid.AttrWrap(self.listbox, 'body'), 
            header=urwid.AttrWrap(self.header, 'head'), 
            footer=self.footer)

    def main(self):
        """Run the program."""
        
        self.loop = urwid.MainLoop(self.view, self.palette,
            unhandled_input=self.unhandled_input)
        self.loop.run()
    
        # on exit, write the flagged filenames to the console
        names = [escape_filename_sh(x) for x in get_flagged_names()]
        print " ".join(names)

    def unhandled_input(self, k):
        # update display of focus directory
        if k in ('q','Q'):
            raise urwid.ExitMainLoop()


def main():
    DirectoryBrowser().main()




#######
# global cache of widgets
_widget_cache = {}

def add_widget(path, widget):
    """Add the widget for a given path"""

    _widget_cache[path] = widget

def get_flagged_names():
    """Return a list of all filenames marked as flagged."""
    
    l = []
    for w in _widget_cache.values():
        if w.flagged:
            l.append(w.get_node().get_value())
    return l
            


######
# store path components of initial current working directory
_initial_cwd = []

def store_initial_cwd(name):
    """Store the initial current working directory path components."""
    
    global _initial_cwd
    _initial_cwd = name.split(dir_sep())

def starts_expanded(name):
    """Return True if directory is a parent of initial cwd."""

    if name is '/':
        return True
    
    l = name.split(dir_sep())
    if len(l) > len(_initial_cwd):
        return False
    
    if l != _initial_cwd[:len(l)]:
        return False
    
    return True


def escape_filename_sh(name):
    """Return a hopefully safe shell-escaped version of a filename."""

    # check whether we have unprintable characters
    for ch in name: 
        if ord(ch) < 32: 
            # found one so use the ansi-c escaping
            return escape_filename_sh_ansic(name)
            
    # all printable characters, so return a double-quoted version
    name.replace('\\','\\\\')
    name.replace('"','\\"')
    name.replace('`','\\`')
    name.replace('$','\\$')
    return '"'+name+'"'


def escape_filename_sh_ansic(name):
    """Return an ansi-c shell-escaped version of a filename."""
    
    out =[]
    # gather the escaped characters into a list
    for ch in name:
        if ord(ch) < 32:
            out.append("\\x%02x"% ord(ch))
        elif ch == '\\':
            out.append('\\\\')
        else:
            out.append(ch)
            
    # slap them back together in an ansi-c quote  $'...'
    return "$'" + "".join(out) + "'"


def sensible_cmp(name_a, name_b):
    """Case insensitive compare with sensible numeric ordering.
    
    "blah7" < "BLAH08" < "blah9" < "blah10" """
    
    # ai, bi are indexes into name_a, name_b
    ai = bi = 0
    
    def next_atom(name, i):
        """Return the next 'atom' and the next index.
        
        An 'atom' is either a nonnegative integer or an uppercased 
        character used for defining sort order."""
        
        a = name[i].upper()
        i += 1
        if a.isdigit():
            while i < len(name) and name[i].isdigit():
                a += name[i]
                i += 1
            a = long(a)
        return a, i
        
    # compare one atom at a time
    while ai < len(name_a) and bi < len(name_b):
        a, ai = next_atom(name_a, ai)
        b, bi = next_atom(name_b, bi)
        if a < b: return -1
        if a > b: return 1
    
    # if all out of atoms to compare, do a regular cmp
    if ai == len(name_a) and bi == len(name_b): 
        return cmp(name_a,name_b)
    
    # the shorter one comes first
    if ai == len(name_a): return -1
    return 1


def dir_sep():
    """Return the separator used in this os."""
    return getattr(os.path,'sep','/')


if __name__=="__main__": 
    main()