/brz/remove-bazaar

# Copyright (C) 2010 Jelmer Vernooij <jelmer@samba.org>

#

# This program is free software; you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation; either version 2 of the License, or

# (at your option) any later version.

#

# This program 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 General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

"""A Git repository implementation that uses a Bazaar transport."""

from cStringIO import StringIO

from dulwich.errors import (

    NotGitRepository,

    NoIndexPresent,

    )

from dulwich.objects import (

    ShaFile,

    )

from dulwich.object_store import (

    PackBasedObjectStore,

    PACKDIR,

    )

from dulwich.pack import (

    PackData,

    Pack,

    iter_sha1,

    load_pack_index_file,

    write_pack_index_v2,

    )

from dulwich.repo import (

    BaseRepo,

    RefsContainer,

    INDEX_FILENAME,

    OBJECTDIR,

    REFSDIR,

    SYMREF,

    check_ref_format,

    read_packed_refs_with_peeled,

    read_packed_refs,

    write_packed_refs,

    )

from bzrlib.errors import (

    FileExists,

    NoSuchFile,

    TransportNotPossible,

    )

class TransportRefsContainer(RefsContainer):

    """Refs container that reads refs from a transport."""

    def __init__(self, transport):

        self.transport = transport

        self._packed_refs = None

        self._peeled_refs = None

    def __repr__(self):

        return "%s(%r)" % (self.__class__.__name__, self.transport)

    def _ensure_dir_exists(self, path):

        for n in range(path.count("/")):

            dirname = "/".join(path.split("/")[:n+1])

            try:

                self.transport.mkdir(dirname)

            except FileExists:

                pass

    def subkeys(self, base):

        keys = set()

        try:

            iter_files = self.transport.clone(base).iter_files_recursive()

            keys.update(("%s/%s" % (base, refname)).strip("/") for 

                    refname in iter_files if check_ref_format("%s/%s" % (base, refname)))

        except (TransportNotPossible, NoSuchFile):

            pass

        for key in self.get_packed_refs():

            if key.startswith(base):

                keys.add(key[len(base):].strip("/"))

        return keys

    def allkeys(self):

        keys = set()

        if self.transport.has("HEAD"):

            keys.add("HEAD")

        try:

            iter_files = list(self.transport.clone("refs").iter_files_recursive())

            for filename in iter_files:

                refname = "refs/%s" % filename

                if check_ref_format(refname):

                    keys.add(refname)

        except (TransportNotPossible, NoSuchFile):

            pass

        keys.update(self.get_packed_refs())

        return keys

    def get_packed_refs(self):

        """Get contents of the packed-refs file.

        :return: Dictionary mapping ref names to SHA1s

        :note: Will return an empty dictionary when no packed-refs file is

            present.

        """

        # TODO: invalidate the cache on repacking

        if self._packed_refs is None:

            # set both to empty because we want _peeled_refs to be

            # None if and only if _packed_refs is also None.

            self._packed_refs = {}

            self._peeled_refs = {}

            try:

                f = self.transport.get("packed-refs")

            except NoSuchFile:

                return {}

            try:

                first_line = iter(f).next().rstrip()

                if (first_line.startswith("# pack-refs") and " peeled" in

                        first_line):

                    for sha, name, peeled in read_packed_refs_with_peeled(f):

                        self._packed_refs[name] = sha

                        if peeled:

                            self._peeled_refs[name] = peeled

                else:

                    f.seek(0)

                    for sha, name in read_packed_refs(f):

                        self._packed_refs[name] = sha

            finally:

                f.close()

        return self._packed_refs

    def get_peeled(self, name):

        """Return the cached peeled value of a ref, if available.

        :param name: Name of the ref to peel

        :return: The peeled value of the ref. If the ref is known not point to a

            tag, this will be the SHA the ref refers to. If the ref may point to

            a tag, but no cached information is available, None is returned.

        """

        self.get_packed_refs()

        if self._peeled_refs is None or name not in self._packed_refs:

            # No cache: no peeled refs were read, or this ref is loose

            return None

        if name in self._peeled_refs:

            return self._peeled_refs[name]

        else:

            # Known not peelable

            return self[name]

    def read_loose_ref(self, name):

        """Read a reference file and return its contents.

        If the reference file a symbolic reference, only read the first line of

        the file. Otherwise, only read the first 40 bytes.

        :param name: the refname to read, relative to refpath

        :return: The contents of the ref file, or None if the file does not

            exist.

        :raises IOError: if any other error occurs

        """

        try:

            f = self.transport.get(name)

        except NoSuchFile:

            return None

        try:

            header = f.read(len(SYMREF))

            if header == SYMREF:

                # Read only the first line

                return header + iter(f).next().rstrip("\r\n")

            else:

                # Read only the first 40 bytes

                return header + f.read(40-len(SYMREF))

        finally:

            f.close()

    def _remove_packed_ref(self, name):

        if self._packed_refs is None:

            return

        # reread cached refs from disk, while holding the lock

        self._packed_refs = None

        self.get_packed_refs()

        if name not in self._packed_refs:

            return

        del self._packed_refs[name]

        if name in self._peeled_refs:

            del self._peeled_refs[name]

        f = self.transport.open_write_stream("packed-refs")

        try:

            write_packed_refs(f, self._packed_refs, self._peeled_refs)

        finally:

            f.close()

    def set_symbolic_ref(self, name, other):

        """Make a ref point at another ref.

        :param name: Name of the ref to set

        :param other: Name of the ref to point at

        """

        self._check_refname(name)

        self._check_refname(other)

        self._ensure_dir_exists(name)

        self.transport.put_bytes(name, SYMREF + other + '\n')

    def set_if_equals(self, name, old_ref, new_ref):

        """Set a refname to new_ref only if it currently equals old_ref.

        This method follows all symbolic references, and can be used to perform

        an atomic compare-and-swap operation.

        :param name: The refname to set.

        :param old_ref: The old sha the refname must refer to, or None to set

            unconditionally.

        :param new_ref: The new sha the refname will refer to.

        :return: True if the set was successful, False otherwise.

        """

        try:

            realname, _ = self._follow(name)

        except KeyError:

            realname = name

        self._ensure_dir_exists(realname)

        self.transport.put_bytes(realname, new_ref+"\n")

        return True

    def add_if_new(self, name, ref):

        """Add a new reference only if it does not already exist.

        This method follows symrefs, and only ensures that the last ref in the

        chain does not exist.

        :param name: The refname to set.

        :param ref: The new sha the refname will refer to.

        :return: True if the add was successful, False otherwise.

        """

        try:

            realname, contents = self._follow(name)

            if contents is not None:

                return False

        except KeyError:

            realname = name

        self._check_refname(realname)

        self._ensure_dir_exists(realname)

        self.transport.put_bytes(realname, ref+"\n")

        return True

    def remove_if_equals(self, name, old_ref):

        """Remove a refname only if it currently equals old_ref.

        This method does not follow symbolic references. It can be used to

        perform an atomic compare-and-delete operation.

        :param name: The refname to delete.

        :param old_ref: The old sha the refname must refer to, or None to delete

            unconditionally.

        :return: True if the delete was successful, False otherwise.

        """

        self._check_refname(name)

        # may only be packed

        try:

            self.transport.delete(name)

        except NoSuchFile:

            pass

        self._remove_packed_ref(name)

        return True

class TransportRepo(BaseRepo):

    def __init__(self, transport):

        self.transport = transport

        try:

            if self.transport.has(".git/%s" % OBJECTDIR):

                self.bare = False

                self._controltransport = self.transport.clone('.git')

            elif self.transport.has(OBJECTDIR) or self.transport.has(REFSDIR):

                self.bare = True

                self._controltransport = self.transport

            else:

                raise NotGitRepository(self.transport)

        except NoSuchFile:

            raise NotGitRepository(self.transport)

        object_store = TransportObjectStore(

            self._controltransport.clone(OBJECTDIR))

        super(TransportRepo, self).__init__(object_store, 

                TransportRefsContainer(self._controltransport))

    def get_named_file(self, path):

        """Get a file from the control dir with a specific name.

        Although the filename should be interpreted as a filename relative to

        the control dir in a disk-baked Repo, the object returned need not be

        pointing to a file in that location.

        :param path: The path to the file, relative to the control dir.

        :return: An open file object, or None if the file does not exist.

        """

        try:

            return self._controltransport.get(path.lstrip('/'))

        except NoSuchFile:

            return None

    def index_path(self):

        """Return the path to the index file."""

        return self._controltransport.local_abspath(INDEX_FILENAME)

    def open_index(self):

        """Open the index for this repository."""

        from dulwich.index import Index

        if not self.has_index():

            raise NoIndexPresent()

        return Index(self.index_path())

    def has_index(self):

        """Check if an index is present."""

        # Bare repos must never have index files; non-bare repos may have a

        # missing index file, which is treated as empty.

        return not self.bare

    def __repr__(self):

        return "<TransportRepo for %r>" % self.transport

class TransportObjectStore(PackBasedObjectStore):

    """Git-style object store that exists on disk."""

    def __init__(self, transport):

        """Open an object store.

        :param transport: Transport to open data from

        """

        super(TransportObjectStore, self).__init__()

        self.transport = transport

        self.pack_transport = self.transport.clone(PACKDIR)

    def _pack_cache_stale(self):

        return False # FIXME

    def _pack_names(self):

        try:

            f = self.transport.get('info/packs')

        except NoSuchFile:

            return self.pack_transport.list_dir(".")

        else:

            ret = []

            for line in f.readlines():

                line = line.rstrip("\n")

                if not line:

                    continue

                (kind, name) = line.split(" ", 1)

                if kind != "P":

                    continue

                ret.append(name)

            return ret

    def _load_packs(self):

        ret = []

        for name in self._pack_names():

            if name.startswith("pack-") and name.endswith(".pack"):

                try:

                    size = self.pack_transport.stat(name).st_size

                except TransportNotPossible:

                    # FIXME: This reads the whole pack file at once

                    f = self.pack_transport.get(name)

                    contents = f.read()

                    pd = PackData(name, StringIO(contents), size=len(contents))

                else:

                    pd = PackData(name, self.pack_transport.get(name),

                            size=size)

                idxname = name.replace(".pack", ".idx")

                idx = load_pack_index_file(idxname, self.pack_transport.get(idxname))

                pack = Pack.from_objects(pd, idx)

                ret.append(pack)

        return ret

    def _iter_loose_objects(self):

        for base in self.transport.list_dir('.'):

            if len(base) != 2:

                continue

            for rest in self.transport.list_dir(base):

                yield base+rest

    def _split_loose_object(self, sha):

        return (sha[:2], sha[2:])

    def _remove_loose_object(self, sha):

        path = '%s/%s' % self._split_loose_object(sha)

        self.transport.delete(path)

    def _get_loose_object(self, sha):

        path = '%s/%s' % self._split_loose_object(sha)

        try:

            return ShaFile.from_file(self.transport.get(path))

        except NoSuchFile:

            return None

    def add_object(self, obj):

        """Add a single object to this object store.

        :param obj: Object to add

        """

        (dir, file) = self._split_loose_object(obj.id)

        try:

            self.transport.mkdir(dir)

        except FileExists:

            pass

        path = "%s/%s" % (dir, file)

        if self.transport.has(path):

            return # Already there, no need to write again

        self.transport.put_bytes(path, obj.as_legacy_object())

    def move_in_pack(self, f):

        """Move a specific file containing a pack into the pack directory.

        :note: The file should be on the same file system as the

            packs directory.

        :param path: Path to the pack file.

        """

        f.seek(0)

        p = PackData(None, f, len(f.getvalue()))

        entries = p.sorted_entries()

        basename = "pack-%s" % iter_sha1(entry[0] for entry in entries)

        f.seek(0)

        self.pack_transport.put_file(basename + ".pack", f)

        idxfile = self.pack_transport.open_write_stream(basename + ".idx")

        try:

            write_pack_index_v2(idxfile, entries, p.get_stored_checksum())

        finally:

            idxfile.close()

        idxfile = self.pack_transport.get(basename + ".idx")

        idx = load_pack_index_file(basename+".idx", idxfile)

        final_pack = Pack.from_objects(p, idx)

        self._add_known_pack(final_pack)

        return final_pack

    def add_pack(self):

        """Add a new pack to this object store. 

        :return: Fileobject to write to and a commit function to 

            call when the pack is finished.

        """

        from cStringIO import StringIO

        f = StringIO()

        def commit():

            if len(f.getvalue()) > 0:

                return self.move_in_pack(f)

            else:

                return None

        return f, commit

    @classmethod

    def init(cls, transport):

        transport.mkdir('info')

        transport.mkdir(PACKDIR)

        return cls(transport)