diff --git a/Lib/packaging/pypi/dist.py b/Lib/packaging/pypi/dist.py
new file mode 100644
index 0000000..16510df
--- /dev/null
+++ b/Lib/packaging/pypi/dist.py
@@ -0,0 +1,547 @@
+"""Classes representing releases and distributions retrieved from indexes.
+
+A project (= unique name) can have several releases (= versions) and
+each release can have several distributions (= sdist and bdists).
+
+Release objects contain metadata-related information (see PEP 376);
+distribution objects contain download-related information.
+"""
+
+import sys
+import mimetypes
+import re
+import tempfile
+import urllib.request
+import urllib.parse
+import urllib.error
+import urllib.parse
+import hashlib
+from shutil import unpack_archive
+
+from packaging.errors import IrrationalVersionError
+from packaging.version import (suggest_normalized_version, NormalizedVersion,
+                               get_version_predicate)
+from packaging.metadata import Metadata
+from packaging.pypi.errors import (HashDoesNotMatch, UnsupportedHashName,
+                                   CantParseArchiveName)
+
+
+__all__ = ['ReleaseInfo', 'DistInfo', 'ReleasesList', 'get_infos_from_url']
+
+EXTENSIONS = ".tar.gz .tar.bz2 .tar .zip .tgz .egg".split()
+MD5_HASH = re.compile(r'^.*#md5=([a-f0-9]+)$')
+DIST_TYPES = ['bdist', 'sdist']
+
+
+class IndexReference:
+    """Mixin used to store the index reference"""
+    def set_index(self, index=None):
+        self._index = index
+
+
+class ReleaseInfo(IndexReference):
+    """Represent a release of a project (a project with a specific version).
+    The release contain the _metadata informations related to this specific
+    version, and is also a container for distribution related informations.
+
+    See the DistInfo class for more information about distributions.
+    """
+
+    def __init__(self, name, version, metadata=None, hidden=False,
+                 index=None, **kwargs):
+        """
+        :param name: the name of the distribution
+        :param version: the version of the distribution
+        :param metadata: the metadata fields of the release.
+        :type metadata: dict
+        :param kwargs: optional arguments for a new distribution.
+        """
+        self.set_index(index)
+        self.name = name
+        self._version = None
+        self.version = version
+        if metadata:
+            self.metadata = Metadata(mapping=metadata)
+        else:
+            self.metadata = None
+        self.dists = {}
+        self.hidden = hidden
+
+        if 'dist_type' in kwargs:
+            dist_type = kwargs.pop('dist_type')
+            self.add_distribution(dist_type, **kwargs)
+
+    def set_version(self, version):
+        try:
+            self._version = NormalizedVersion(version)
+        except IrrationalVersionError:
+            suggestion = suggest_normalized_version(version)
+            if suggestion:
+                self.version = suggestion
+            else:
+                raise IrrationalVersionError(version)
+
+    def get_version(self):
+        return self._version
+
+    version = property(get_version, set_version)
+
+    def fetch_metadata(self):
+        """If the metadata is not set, use the indexes to get it"""
+        if not self.metadata:
+            self._index.get_metadata(self.name, str(self.version))
+        return self.metadata
+
+    @property
+    def is_final(self):
+        """proxy to version.is_final"""
+        return self.version.is_final
+
+    def fetch_distributions(self):
+        if self.dists is None:
+            self._index.get_distributions(self.name, str(self.version))
+            if self.dists is None:
+                self.dists = {}
+        return self.dists
+
+    def add_distribution(self, dist_type='sdist', python_version=None,
+                         **params):
+        """Add distribution informations to this release.
+        If distribution information is already set for this distribution type,
+        add the given url paths to the distribution. This can be useful while
+        some of them fails to download.
+
+        :param dist_type: the distribution type (eg. "sdist", "bdist", etc.)
+        :param params: the fields to be passed to the distribution object
+                       (see the :class:DistInfo constructor).
+        """
+        if dist_type not in DIST_TYPES:
+            raise ValueError(dist_type)
+        if dist_type in self.dists:
+            self.dists[dist_type].add_url(**params)
+        else:
+            self.dists[dist_type] = DistInfo(self, dist_type,
+                                             index=self._index, **params)
+        if python_version:
+            self.dists[dist_type].python_version = python_version
+
+    def get_distribution(self, dist_type=None, prefer_source=True):
+        """Return a distribution.
+
+        If dist_type is set, find first for this distribution type, and just
+        act as an alias of __get_item__.
+
+        If prefer_source is True, search first for source distribution, and if
+        not return one existing distribution.
+        """
+        if len(self.dists) == 0:
+            raise LookupError()
+        if dist_type:
+            return self[dist_type]
+        if prefer_source:
+            if "sdist" in self.dists:
+                dist = self["sdist"]
+            else:
+                dist = next(self.dists.values())
+            return dist
+
+    def unpack(self, path=None, prefer_source=True):
+        """Unpack the distribution to the given path.
+
+        If not destination is given, creates a temporary location.
+
+        Returns the location of the extracted files (root).
+        """
+        return self.get_distribution(prefer_source=prefer_source)\
+                   .unpack(path=path)
+
+    def download(self, temp_path=None, prefer_source=True):
+        """Download the distribution, using the requirements.
+
+        If more than one distribution match the requirements, use the last
+        version.
+        Download the distribution, and put it in the temp_path. If no temp_path
+        is given, creates and return one.
+
+        Returns the complete absolute path to the downloaded archive.
+        """
+        return self.get_distribution(prefer_source=prefer_source)\
+                   .download(path=temp_path)
+
+    def set_metadata(self, metadata):
+        if not self.metadata:
+            self.metadata = Metadata()
+        self.metadata.update(metadata)
+
+    def __getitem__(self, item):
+        """distributions are available using release["sdist"]"""
+        return self.dists[item]
+
+    def _check_is_comparable(self, other):
+        if not isinstance(other, ReleaseInfo):
+            raise TypeError("cannot compare %s and %s"
+                % (type(self).__name__, type(other).__name__))
+        elif self.name != other.name:
+            raise TypeError("cannot compare %s and %s"
+                % (self.name, other.name))
+
+    def __repr__(self):
+        return "<%s %s>" % (self.name, self.version)
+
+    def __eq__(self, other):
+        self._check_is_comparable(other)
+        return self.version == other.version
+
+    def __lt__(self, other):
+        self._check_is_comparable(other)
+        return self.version < other.version
+
+    def __ne__(self, other):
+        return not self.__eq__(other)
+
+    def __gt__(self, other):
+        return not (self.__lt__(other) or self.__eq__(other))
+
+    def __le__(self, other):
+        return self.__eq__(other) or self.__lt__(other)
+
+    def __ge__(self, other):
+        return self.__eq__(other) or self.__gt__(other)
+
+    # See http://docs.python.org/reference/datamodel#object.__hash__
+    __hash__ = object.__hash__
+
+
+class DistInfo(IndexReference):
+    """Represents a distribution retrieved from an index (sdist, bdist, ...)
+    """
+
+    def __init__(self, release, dist_type=None, url=None, hashname=None,
+                 hashval=None, is_external=True, python_version=None,
+                 index=None):
+        """Create a new instance of DistInfo.
+
+        :param release: a DistInfo class is relative to a release.
+        :param dist_type: the type of the dist (eg. source, bin-*, etc.)
+        :param url: URL where we found this distribution
+        :param hashname: the name of the hash we want to use. Refer to the
+                         hashlib.new documentation for more information.
+        :param hashval: the hash value.
+        :param is_external: we need to know if the provided url comes from
+                            an index browsing, or from an external resource.
+
+        """
+        self.set_index(index)
+        self.release = release
+        self.dist_type = dist_type
+        self.python_version = python_version
+        self._unpacked_dir = None
+        # set the downloaded path to None by default. The goal here
+        # is to not download distributions multiple times
+        self.downloaded_location = None
+        # We store urls in dict, because we need to have a bit more infos
+        # than the simple URL. It will be used later to find the good url to
+        # use.
+        # We have two _url* attributes: _url and urls. urls contains a list
+        # of dict for the different urls, and _url contains the choosen url, in
+        # order to dont make the selection process multiple times.
+        self.urls = []
+        self._url = None
+        self.add_url(url, hashname, hashval, is_external)
+
+    def add_url(self, url=None, hashname=None, hashval=None, is_external=True):
+        """Add a new url to the list of urls"""
+        if hashname is not None:
+            try:
+                hashlib.new(hashname)
+            except ValueError:
+                raise UnsupportedHashName(hashname)
+        if not url in [u['url'] for u in self.urls]:
+            self.urls.append({
+                'url': url,
+                'hashname': hashname,
+                'hashval': hashval,
+                'is_external': is_external,
+            })
+            # reset the url selection process
+            self._url = None
+
+    @property
+    def url(self):
+        """Pick up the right url for the list of urls in self.urls"""
+        # We return internal urls over externals.
+        # If there is more than one internal or external, return the first
+        # one.
+        if self._url is None:
+            if len(self.urls) > 1:
+                internals_urls = [u for u in self.urls \
+                                  if u['is_external'] == False]
+                if len(internals_urls) >= 1:
+                    self._url = internals_urls[0]
+            if self._url is None:
+                self._url = self.urls[0]
+        return self._url
+
+    @property
+    def is_source(self):
+        """return if the distribution is a source one or not"""
+        return self.dist_type == 'sdist'
+
+    def download(self, path=None):
+        """Download the distribution to a path, and return it.
+
+        If the path is given in path, use this, otherwise, generates a new one
+        Return the download location.
+        """
+        if path is None:
+            path = tempfile.mkdtemp()
+
+        # if we do not have downloaded it yet, do it.
+        if self.downloaded_location is None:
+            url = self.url['url']
+            archive_name = urllib.parse.urlparse(url)[2].split('/')[-1]
+            filename, headers = urllib.request.urlretrieve(url,
+                                                   path + "/" + archive_name)
+            self.downloaded_location = filename
+            self._check_md5(filename)
+        return self.downloaded_location
+
+    def unpack(self, path=None):
+        """Unpack the distribution to the given path.
+
+        If not destination is given, creates a temporary location.
+
+        Returns the location of the extracted files (root).
+        """
+        if not self._unpacked_dir:
+            if path is None:
+                path = tempfile.mkdtemp()
+
+            filename = self.download(path)
+            content_type = mimetypes.guess_type(filename)[0]
+            unpack_archive(filename, path)
+            self._unpacked_dir = path
+
+        return path
+
+    def _check_md5(self, filename):
+        """Check that the md5 checksum of the given file matches the one in
+        url param"""
+        hashname = self.url['hashname']
+        expected_hashval = self.url['hashval']
+        if not None in (expected_hashval, hashname):
+            with open(filename, 'rb') as f:
+                hashval = hashlib.new(hashname)
+                hashval.update(f.read())
+
+            if hashval.hexdigest() != expected_hashval:
+                raise HashDoesNotMatch("got %s instead of %s"
+                    % (hashval.hexdigest(), expected_hashval))
+
+    def __repr__(self):
+        if self.release is None:
+            return "<? ? %s>" % self.dist_type
+
+        return "<%s %s %s>" % (
+            self.release.name, self.release.version, self.dist_type or "")
+
+
+class ReleasesList(IndexReference):
+    """A container of Release.
+
+    Provides useful methods and facilities to sort and filter releases.
+    """
+    def __init__(self, name, releases=None, contains_hidden=False, index=None):
+        self.set_index(index)
+        self.releases = []
+        self.name = name
+        self.contains_hidden = contains_hidden
+        if releases:
+            self.add_releases(releases)
+
+    def fetch_releases(self):
+        self._index.get_releases(self.name)
+        return self.releases
+
+    def filter(self, predicate):
+        """Filter and return a subset of releases matching the given predicate.
+        """
+        return ReleasesList(self.name, [release for release in self.releases
+                                        if predicate.match(release.version)],
+                                        index=self._index)
+
+    def get_last(self, requirements, prefer_final=None):
+        """Return the "last" release, that satisfy the given predicates.
+
+        "last" is defined by the version number of the releases, you also could
+        set prefer_final parameter to True or False to change the order results
+        """
+        predicate = get_version_predicate(requirements)
+        releases = self.filter(predicate)
+        if len(releases) == 0:
+            return None
+        releases.sort_releases(prefer_final, reverse=True)
+        return releases[0]
+
+    def add_releases(self, releases):
+        """Add releases in the release list.
+
+        :param: releases is a list of ReleaseInfo objects.
+        """
+        for r in releases:
+            self.add_release(release=r)
+
+    def add_release(self, version=None, dist_type='sdist', release=None,
+                    **dist_args):
+        """Add a release to the list.
+
+        The release can be passed in the `release` parameter, and in this case,
+        it will be crawled to extract the useful informations if necessary, or
+        the release informations can be directly passed in the `version` and
+        `dist_type` arguments.
+
+        Other keywords arguments can be provided, and will be forwarded to the
+        distribution creation (eg. the arguments of the DistInfo constructor).
+        """
+        if release:
+            if release.name.lower() != self.name.lower():
+                raise ValueError("%s is not the same project as %s" %
+                                 (release.name, self.name))
+            version = str(release.version)
+
+            if not version in self.get_versions():
+                # append only if not already exists
+                self.releases.append(release)
+            for dist in release.dists.values():
+                for url in dist.urls:
+                    self.add_release(version, dist.dist_type, **url)
+        else:
+            matches = [r for r in self.releases
+                       if str(r.version) == version and r.name == self.name]
+            if not matches:
+                release = ReleaseInfo(self.name, version, index=self._index)
+                self.releases.append(release)
+            else:
+                release = matches[0]
+
+            release.add_distribution(dist_type=dist_type, **dist_args)
+
+    def sort_releases(self, prefer_final=False, reverse=True, *args, **kwargs):
+        """Sort the results with the given properties.
+
+        The `prefer_final` argument can be used to specify if final
+        distributions (eg. not dev, bet or alpha) would be prefered or not.
+
+        Results can be inverted by using `reverse`.
+
+        Any other parameter provided will be forwarded to the sorted call. You
+        cannot redefine the key argument of "sorted" here, as it is used
+        internally to sort the releases.
+        """
+
+        sort_by = []
+        if prefer_final:
+            sort_by.append("is_final")
+        sort_by.append("version")
+
+        self.releases.sort(
+            key=lambda i: tuple(getattr(i, arg) for arg in sort_by),
+            reverse=reverse, *args, **kwargs)
+
+    def get_release(self, version):
+        """Return a release from its version."""
+        matches = [r for r in self.releases if str(r.version) == version]
+        if len(matches) != 1:
+            raise KeyError(version)
+        return matches[0]
+
+    def get_versions(self):
+        """Return a list of releases versions contained"""
+        return [str(r.version) for r in self.releases]
+
+    def __getitem__(self, key):
+        return self.releases[key]
+
+    def __len__(self):
+        return len(self.releases)
+
+    def __repr__(self):
+        string = 'Project "%s"' % self.name
+        if self.get_versions():
+            string += ' versions: %s' % ', '.join(self.get_versions())
+        return '<%s>' % string
+
+
+def get_infos_from_url(url, probable_dist_name=None, is_external=True):
+    """Get useful informations from an URL.
+
+    Return a dict of (name, version, url, hashtype, hash, is_external)
+
+    :param url: complete url of the distribution
+    :param probable_dist_name: A probable name of the project.
+    :param is_external: Tell if the url commes from an index or from
+                        an external URL.
+    """
+    # if the url contains a md5 hash, get it.
+    md5_hash = None
+    match = MD5_HASH.match(url)
+    if match is not None:
+        md5_hash = match.group(1)
+        # remove the hash
+        url = url.replace("#md5=%s" % md5_hash, "")
+
+    # parse the archive name to find dist name and version
+    archive_name = urllib.parse.urlparse(url)[2].split('/')[-1]
+    extension_matched = False
+    # remove the extension from the name
+    for ext in EXTENSIONS:
+        if archive_name.endswith(ext):
+            archive_name = archive_name[:-len(ext)]
+            extension_matched = True
+
+    name, version = split_archive_name(archive_name)
+    if extension_matched is True:
+        return {'name': name,
+                'version': version,
+                'url': url,
+                'hashname': "md5",
+                'hashval': md5_hash,
+                'is_external': is_external,
+                'dist_type': 'sdist'}
+
+
+def split_archive_name(archive_name, probable_name=None):
+    """Split an archive name into two parts: name and version.
+
+    Return the tuple (name, version)
+    """
+    # Try to determine wich part is the name and wich is the version using the
+    # "-" separator. Take the larger part to be the version number then reduce
+    # if this not works.
+    def eager_split(str, maxsplit=2):
+        # split using the "-" separator
+        splits = str.rsplit("-", maxsplit)
+        name = splits[0]
+        version = "-".join(splits[1:])
+        if version.startswith("-"):
+            version = version[1:]
+        if suggest_normalized_version(version) is None and maxsplit >= 0:
+            # we dont get a good version number: recurse !
+            return eager_split(str, maxsplit - 1)
+        else:
+            return name, version
+    if probable_name is not None:
+        probable_name = probable_name.lower()
+    name = None
+    if probable_name is not None and probable_name in archive_name:
+        # we get the name from probable_name, if given.
+        name = probable_name
+        version = archive_name.lstrip(name)
+    else:
+        name, version = eager_split(archive_name)
+
+    version = suggest_normalized_version(version)
+    if version is not None and name != "":
+        return name.lower(), version
+    else:
+        raise CantParseArchiveName(archive_name)