"""Utilities for extracting common archive formats"""


__all__ = [
    "unpack_archive", "unpack_zipfile", "unpack_tarfile", "default_filter",
    "UnrecognizedFormat", "extraction_drivers"
]

import zipfile, tarfile, os
from pkg_resources import ensure_directory

class UnrecognizedFormat(RuntimeError):
    """Couldn't recognize the archive type"""

def default_filter(src,dst):
    """The default progress/filter callback; returns True for all files"""
    
    return True























def unpack_archive(filename, extract_dir, progress_filter=default_filter,
    drivers=None
):
    """Unpack `filename` to `extract_dir`, or raise ``UnrecognizedFormat``

    `progress_filter` is a function taking two arguments: a source path
    internal to the archive ('/'-separated), and a filesystem path where it
    will be extracted.  The callback must return a true value, or else that
    file or directory will be skipped.  The callback can thus be used to
    report on the progress of the extraction, as well as to filter the items
    extracted.

    `drivers`, if supplied, must be a non-empty sequence of functions with the
    same signature as this function (minus the `drivers` argument), that raise
    ``UnrecognizedFormat`` if they do not support extracting the designated
    archive type.  The `drivers` are tried in sequence until one is found that
    does not raise an error, or until all are exhausted (in which case
    ``UnrecognizedFormat`` is raised).  If you do not supply a sequence of
    drivers, the module's ``extraction_drivers`` constant will be used, which
    means that ``unpack_zipfile`` and ``unpack_tarfile`` will be tried, in that
    order.
    """
    for driver in drivers or extraction_drivers:
        try:
            driver(filename, extract_dir, progress_filter)
        except UnrecognizedFormat:
            continue
        else:
            return
    else:
        raise UnrecognizedFormat(
            "Not a recognized archive type: %s" % filename
        )








def unpack_zipfile(filename, extract_dir, progress_filter=default_filter):
    """Unpack zip `filename` to `extract_dir`

    Raises ``UnrecognizedFormat`` if `filename` is not a zipfile (as determined
    by ``zipfile.is_zipfile()``).  See ``unpack_archive()`` for an explanation
    of the `progress_filter` argument.
    """

    if not zipfile.is_zipfile(filename):
        raise UnrecognizedFormat("%s is not a zip file" % (filename,))

    z = zipfile.ZipFile(filename)
    try:
        for info in z.infolist():
            name = info.filename

            # don't extract absolute paths or ones with .. in them
            if name.startswith('/') or '..' in name:
                continue

            target = os.path.join(extract_dir,name)
            if not progress_filter(name,target):
                continue
            if name.endswith('/'):
                # directory
                ensure_directory(target)
            else:
                # file
                ensure_directory(target)
                data = z.read(info.filename)
                f = open(target,'wb')
                try:
                    f.write(data)
                finally:
                    f.close()
                    del data
    finally:
        z.close()



def unpack_tarfile(filename, extract_dir, progress_filter=default_filter):
    """Unpack tar/tar.gz/tar.bz2 `filename` to `extract_dir`

    Raises ``UnrecognizedFormat`` if `filename` is not a tarfile (as determined
    by ``tarfile.open()``).  See ``unpack_archive()`` for an explanation
    of the `progress_filter` argument.
    """

    try:
        tarobj = tarfile.open(filename)
    except tarfile.TarError:
        raise UnrecognizedFormat(
            "%s is not a compressed or uncompressed tar file" % (filename,)
        )

    try:
        tarobj.chown = lambda *args: None   # don't do any chowning!
        for member in tarobj:
            if member.isfile() or member.isdir():
                name = member.name
                # don't extract absolute paths or ones with .. in them
                if not name.startswith('/') and '..' not in name:
                    dst = os.path.join(extract_dir, *name.split('/'))                
                    if progress_filter(name, dst):
                        tarobj.extract(member,extract_dir)
        return True
    finally:
        tarobj.close()




extraction_drivers = unpack_zipfile, unpack_tarfile