Sindbad~EG File Manager

"""distutils.filelist

Provides the FileList class, used for poking about the filesystem
and building lists of files.
"""

import os
import re
import fnmatch
import functools

from distutils.util import convert_path
from distutils.errors import DistutilsTemplateError, DistutilsInternalError
from distutils import log


class FileList:
    """A list of files built by on exploring the filesystem and filtered by
    applying various patterns to what we find there.

    Instance attributes:
      dir
        directory from which files will be taken -- only used if
        'allfiles' not supplied to constructor
      files
        list of filenames currently being built/filtered/manipulated
      allfiles
        complete list of files under consideration (ie. without any
        filtering applied)
    """

    def __init__(self, warn=None, debug_print=None):
        # ignore argument to FileList, but keep them for backwards
        # compatibility
        self.allfiles = None
        self.files = []

    def set_allfiles(self, allfiles):
        self.allfiles = allfiles

    def findall(self, dir=os.curdir):
        self.allfiles = findall(dir)

    def debug_print(self, msg):
        """Print 'msg' to stdout if the global DEBUG (taken from the
        DISTUTILS_DEBUG environment variable) flag is true.
        """
        from distutils.debug import DEBUG
        if DEBUG:
            print(msg)

    # Collection methods

    def append(self, item):
        self.files.append(item)

    def extend(self, items):
        self.files.extend(items)

    def sort(self):
        # Not a strict lexical sort!
        sortable_files = sorted(map(os.path.split, self.files))
        self.files = []
        for sort_tuple in sortable_files:
            self.files.append(os.path.join(*sort_tuple))

    # Other miscellaneous utility methods

    def remove_duplicates(self):
        # Assumes list has been sorted!
        for i in range(len(self.files) - 1, 0, -1):
            if self.files[i] == self.files[i - 1]:
                del self.files[i]

    # "File template" methods

    def _parse_template_line(self, line):
        words = line.split()
        action = words[0]

        patterns = dir = dir_pattern = None

        if action in ('include', 'exclude',
                      'global-include', 'global-exclude'):
            if len(words) < 2:
                raise DistutilsTemplateError(
                      "'%s' expects <pattern1> <pattern2> ..." % action)
            patterns = [convert_path(w) for w in words[1:]]
        elif action in ('recursive-include', 'recursive-exclude'):
            if len(words) < 3:
                raise DistutilsTemplateError(
                      "'%s' expects <dir> <pattern1> <pattern2> ..." % action)
            dir = convert_path(words[1])
            patterns = [convert_path(w) for w in words[2:]]
        elif action in ('graft', 'prune'):
            if len(words) != 2:
                raise DistutilsTemplateError(
                      "'%s' expects a single <dir_pattern>" % action)
            dir_pattern = convert_path(words[1])
        else:
            raise DistutilsTemplateError("unknown action '%s'" % action)

        return (action, patterns, dir, dir_pattern)

    def process_template_line(self, line):
        # Parse the line: split it up, make sure the right number of words
        # is there, and return the relevant words.  'action' is always
        # defined: it's the first word of the line.  Which of the other
        # three are defined depends on the action; it'll be either
        # patterns, (dir and patterns), or (dir_pattern).
        (action, patterns, dir, dir_pattern) = self._parse_template_line(line)

        # OK, now we know that the action is valid and we have the
        # right number of words on the line for that action -- so we
        # can proceed with minimal error-checking.
        if action == 'include':
            self.debug_print("include " + ' '.join(patterns))
            for pattern in patterns:
                if not self.include_pattern(pattern, anchor=1):
                    log.warn("warning: no files found matching '%s'",
                             pattern)

        elif action == 'exclude':
            self.debug_print("exclude " + ' '.join(patterns))
            for pattern in patterns:
                if not self.exclude_pattern(pattern, anchor=1):
                    log.warn(("warning: no previously-included files "
                              "found matching '%s'"), pattern)

        elif action == 'global-include':
            self.debug_print("global-include " + ' '.join(patterns))
            for pattern in patterns:
                if not self.include_pattern(pattern, anchor=0):
                    log.warn(("warning: no files found matching '%s' "
                              "anywhere in distribution"), pattern)

        elif action == 'global-exclude':
            self.debug_print("global-exclude " + ' '.join(patterns))
            for pattern in patterns:
                if not self.exclude_pattern(pattern, anchor=0):
                    log.warn(("warning: no previously-included files matching "
                              "'%s' found anywhere in distribution"),
                             pattern)

        elif action == 'recursive-include':
            self.debug_print("recursive-include %s %s" %
                             (dir, ' '.join(patterns)))
            for pattern in patterns:
                if not self.include_pattern(pattern, prefix=dir):
                    msg = (
                        "warning: no files found matching '%s' "
                        "under directory '%s'"
                    )
                    log.warn(msg, pattern, dir)

        elif action == 'recursive-exclude':
            self.debug_print("recursive-exclude %s %s" %
                             (dir, ' '.join(patterns)))
            for pattern in patterns:
                if not self.exclude_pattern(pattern, prefix=dir):
                    log.warn(("warning: no previously-included files matching "
                              "'%s' found under directory '%s'"),
                             pattern, dir)

        elif action == 'graft':
            self.debug_print("graft " + dir_pattern)
            if not self.include_pattern(None, prefix=dir_pattern):
                log.warn("warning: no directories found matching '%s'",
                         dir_pattern)

        elif action == 'prune':
            self.debug_print("prune " + dir_pattern)
            if not self.exclude_pattern(None, prefix=dir_pattern):
                log.warn(("no previously-included directories found "
                          "matching '%s'"), dir_pattern)
        else:
            raise DistutilsInternalError(
                  "this cannot happen: invalid action '%s'" % action)

    # Filtering/selection methods

    def include_pattern(self, pattern, anchor=1, prefix=None, is_regex=0):
        """Select strings (presumably filenames) from 'self.files' that
        match 'pattern', a Unix-style wildcard (glob) pattern.  Patterns
        are not quite the same as implemented by the 'fnmatch' module: '*'
        and '?'  match non-special characters, where "special" is platform-
        dependent: slash on Unix; colon, slash, and backslash on
        DOS/Windows; and colon on Mac OS.

        If 'anchor' is true (the default), then the pattern match is more
        stringent: "*.py" will match "foo.py" but not "foo/bar.py".  If
        'anchor' is false, both of these will match.

        If 'prefix' is supplied, then only filenames starting with 'prefix'
        (itself a pattern) and ending with 'pattern', with anything in between
        them, will match.  'anchor' is ignored in this case.

        If 'is_regex' is true, 'anchor' and 'prefix' are ignored, and
        'pattern' is assumed to be either a string containing a regex or a
        regex object -- no translation is done, the regex is just compiled
        and used as-is.

        Selected strings will be added to self.files.

        Return True if files are found, False otherwise.
        """
        # XXX docstring lying about what the special chars are?
        files_found = False
        pattern_re = translate_pattern(pattern, anchor, prefix, is_regex)
        self.debug_print("include_pattern: applying regex r'%s'" %
                         pattern_re.pattern)

        # delayed loading of allfiles list
        if self.allfiles is None:
            self.findall()

        for name in self.allfiles:
            if pattern_re.search(name):
                self.debug_print(" adding " + name)
                self.files.append(name)
                files_found = True
        return files_found

    def exclude_pattern(
            self, pattern, anchor=1, prefix=None, is_regex=0):
        """Remove strings (presumably filenames) from 'files' that match
        'pattern'.  Other parameters are the same as for
        'include_pattern()', above.
        The list 'self.files' is modified in place.
        Return True if files are found, False otherwise.
        """
        files_found = False
        pattern_re = translate_pattern(pattern, anchor, prefix, is_regex)
        self.debug_print("exclude_pattern: applying regex r'%s'" %
                         pattern_re.pattern)
        for i in range(len(self.files)-1, -1, -1):
            if pattern_re.search(self.files[i]):
                self.debug_print(" removing " + self.files[i])
                del self.files[i]
                files_found = True
        return files_found


# Utility functions

def _find_all_simple(path):
    """
    Find all files under 'path'
    """
    all_unique = _UniqueDirs.filter(os.walk(path, followlinks=True))
    results = (
        os.path.join(base, file)
        for base, dirs, files in all_unique
        for file in files
    )
    return filter(os.path.isfile, results)


class _UniqueDirs(set):
    """
    Exclude previously-seen dirs from walk results,
    avoiding infinite recursion.
    Ref https://bugs.python.org/issue44497.
    """
    def __call__(self, walk_item):
        """
        Given an item from an os.walk result, determine
        if the item represents a unique dir for this instance
        and if not, prevent further traversal.
        """
        base, dirs, files = walk_item
        stat = os.stat(base)
        candidate = stat.st_dev, stat.st_ino
        found = candidate in self
        if found:
            del dirs[:]
        self.add(candidate)
        return not found

    @classmethod
    def filter(cls, items):
        return filter(cls(), items)


def findall(dir=os.curdir):
    """
    Find all files under 'dir' and return the list of full filenames.
    Unless dir is '.', return full filenames with dir prepended.
    """
    files = _find_all_simple(dir)
    if dir == os.curdir:
        make_rel = functools.partial(os.path.relpath, start=dir)
        files = map(make_rel, files)
    return list(files)


def glob_to_re(pattern):
    """Translate a shell-like glob pattern to a regular expression; return
    a string containing the regex.  Differs from 'fnmatch.translate()' in
    that '*' does not match "special characters" (which are
    platform-specific).
    """
    pattern_re = fnmatch.translate(pattern)

    # '?' and '*' in the glob pattern become '.' and '.*' in the RE, which
    # IMHO is wrong -- '?' and '*' aren't supposed to match slash in Unix,
    # and by extension they shouldn't match such "special characters" under
    # any OS.  So change all non-escaped dots in the RE to match any
    # character except the special characters (currently: just os.sep).
    sep = os.sep
    if os.sep == '\\':
        # we're using a regex to manipulate a regex, so we need
        # to escape the backslash twice
        sep = r'\\\\'
    escaped = r'\1[^%s]' % sep
    pattern_re = re.sub(r'((?<!\\)(\\\\)*)\.', escaped, pattern_re)
    return pattern_re


def translate_pattern(pattern, anchor=1, prefix=None, is_regex=0):
    """Translate a shell-like wildcard pattern to a compiled regular
    expression.  Return the compiled regex.  If 'is_regex' true,
    then 'pattern' is directly compiled to a regex (if it's a string)
    or just returned as-is (assumes it's a regex object).
    """
    if is_regex:
        if isinstance(pattern, str):
            return re.compile(pattern)
        else:
            return pattern

    # ditch start and end characters
    start, _, end = glob_to_re('_').partition('_')

    if pattern:
        pattern_re = glob_to_re(pattern)
        assert pattern_re.startswith(start) and pattern_re.endswith(end)
    else:
        pattern_re = ''

    if prefix is not None:
        prefix_re = glob_to_re(prefix)
        assert prefix_re.startswith(start) and prefix_re.endswith(end)
        prefix_re = prefix_re[len(start): len(prefix_re) - len(end)]
        sep = os.sep
        if os.sep == '\\':
            sep = r'\\'
        pattern_re = pattern_re[len(start): len(pattern_re) - len(end)]
        pattern_re = r'%s\A%s%s.*%s%s' % (
            start, prefix_re, sep, pattern_re, end)
    else:                               # no prefix -- respect anchor flag
        if anchor:
            pattern_re = r'%s\A%s' % (start, pattern_re[len(start):])

    return re.compile(pattern_re)