root/dirtree.py

# Copyright (C) 2007, Stefan Schwarzer
#
# Permission is hereby granted, free of charge, to any person
# obtaining a copy of this software and associated documentation files
# (the "Software"), to deal in the Software without restriction,
# including without limitation the rights to use, copy, modify, merge,
# publish, distribute, sublicense, and/or sell copies of the Software,
# and to permit persons to whom the Software is furnished to do so,
# subject to the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

import fnmatch
import itertools
import os
import stat
import sys

# Websourcebrowser modules
import config


class ReadError(Exception):
    pass


def dir_level(path):
    """
    Return the "depth" of a directory, here defined as the number of
    directory separators in the string `path`.
    """
    level = path.count(os.sep)
    if level == 1 and path.endswith(os.sep):
        return 0
    else:
        return level


class _ItemFamily(object):
    """
    Store parent, previous and next sibling items.
    """
    def __init__(self):
        self.parent = self.previous = self.next = ""

    def __repr__(self):
        return '<%s object with parent="%s", previous="%s", next="%s">' % \
               (self.__class__.__name__, self.parent, self.previous, self.next)


class DirectoryTree(object):
    def __init__(self, root):
        self.root = os.path.abspath(os.path.normpath(root))

    def walk(self, path, depth=sys.maxint, _max_level=None):
        """
        Return a generator function which recursively yields the items
        (directories and files) with their full paths, starting at the
        root `path`. On each level, the items are sorted with
        directories first, then regular files.

        If `depth` is given, it's taken for the maximum recursion
        depth of the algorithm, i. e. if `depth` is 1, no recursion is
        done, only the directories and files in `path` are listed. By
        default, the directory `path` with all its nested
        subdirectories is visited.

        Like with `os.walk`, if a directory is really a symbolic link,
        it will be listed but not visited to avoid infinite link
        cycles.
        """
        path = os.path.abspath(path)
        if _max_level is None:
            _max_level = dir_level(path) + depth + 1
        # `listdir` doesn't return items with path separators
        try:
            dirs_and_files = os.listdir(path)
        except OSError:
            return
        # filter out other items than directories and files and add a
        #  priority value for sorting
        for index, item in enumerate(dirs_and_files):
            joined_path = os.path.join(path, item)
            try:
                item_mode = os.stat(joined_path)[0]
            except OSError:
                priority = 0
                dirs_and_files[index] = (priority, item)
                continue
            if stat.S_ISDIR(item_mode):
                priority = 1
            elif stat.S_ISREG(item_mode):
                priority = 2
            else:
                # ignore sockets, device files etc.
                priority = 0
            # prepend priority value (1 for directories, 2 for files, 0 else)
            dirs_and_files[index] = (priority, item)
        # remove items with priority 0
        dirs_and_files = [item for item in dirs_and_files if item[0]]
        # sort by priority, then basename
        dirs_and_files.sort()
        # yield the sorted items, if necessary, recursively
        for priority, item in dirs_and_files:
            item = os.path.join(path, item)
            yield item
            is_directory = (priority == 1)
            follow_non_link = is_directory and not os.path.islink(item)
            levels_left = (dir_level(item) + 1 < _max_level)
            if is_directory and follow_non_link and levels_left:
                for inner_item in self.walk(item, _max_level=_max_level):
                    yield inner_item

    def _ignore_item(self, item):
        """
        Return `True` if the path `item` should be omitted from the
        list of directories and files, else return `False`.
        """
        for pattern in config.ignore_patterns:
            if fnmatch.fnmatch(item, pattern):
                return True
        return False

    def read(self, depth=sys.maxint):
        """
        Read a directory tree `depth` levels deep. A level 1 means
        just the flat directory contents. If the root directory
        (`self.root`) can't be scanned, raise a `ReadError`.

        If the method executes successfully, the instance attribute
        `items` will return a list of the read file system items. The
        items will have the ignore patterns in `config.ignore_patterns`
        already applied. The instance attribute `family` will contain
        a mapping from each item (strings) to an object with the
        attributes `parent`, `previous` and `next`. These are the
        respective items for the parent and the previous and next
        sibling (i. e. previous and next items immediately below the
        same directory). If one of the three paths can't sensibly be
        given, it's set to `None`. Note that the parent directory is
        set to `None` if it's the root directory for the read process.
        """
        if not os.access(self.root, os.R_OK):
            raise ReadError("root '%s' can't be scanned" % self.root)
        # read and filter items
        self.items = list(
          itertools.ifilterfalse(self._ignore_item,
                                 self.walk(self.root, depth=depth)))

    def __str__(self):
        return "\n".join(self.items)


if __name__ == '__main__':
    # test code
    config.set_from_environment()
    dt = DirectoryTree(root="/home/schwa/sd/pypy-dist")
    dt.read()