~bzr-pqm/bzr/bzr.dev

#! /usr/bin/env python

# 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

"""XML externalization support."""

# "XML is like violence: if it doesn't solve your problem, you aren't

# using enough of it." -- various

# importing this module is fairly slow because it has to load several

# ElementTree bits

from bzrlib.trace import mutter, warning

try:

    from cElementTree import (ElementTree, SubElement, Element,

                              XMLTreeBuilder, fromstring, tostring)

except ImportError:

    from warnings import warn

    warn('using slower ElementTree; consider installing cElementTree')

    from util.elementtree.ElementTree import (ElementTree, SubElement,

                                              Element, XMLTreeBuilder,

                                              fromstring, tostring)

from bzrlib.inventory import ROOT_ID, Inventory, InventoryEntry

from bzrlib.revision import Revision, RevisionReference        

from bzrlib.errors import BzrError

class Serializer(object):

    """Abstract object serialize/deserialize"""

    def write_inventory(self, inv, f):

        """Write inventory to a file"""

        elt = self._pack_inventory(inv)

        self._write_element(elt, f)

    def write_inventory_to_string(self, inv):

        return tostring(self._pack_inventory(inv))

    def read_inventory_from_string(self, xml_string):

        return self._unpack_inventory(fromstring(xml_string))

    def read_inventory(self, f):

        return self._unpack_inventory(self._read_element(f))

    def write_revision(self, rev, f):

        self._write_element(self._pack_revision(rev), f)

    def write_revision_to_string(self, rev):

        return tostring(self._pack_revision(rev), f)

    def read_revision(self, f):

        return self._unpack_revision(self._read_element(f))

    def read_revision_from_string(self, xml_string):

        return self._unpack_revision(fromstring(xml_string))

    def _write_element(self, elt, f):

        ElementTree(elt).write(f, 'utf-8')

        f.write('\n')

    def _read_element(self, f):

        return ElementTree().parse(f)

class _Serializer_v4(Serializer):

    """Version 0.0.4 serializer

    You should use the serialzer_v4 singleton."""

    __slots__ = []

    def _pack_inventory(self, inv):

        """Convert to XML Element"""

        e = Element('inventory')

        e.text = '\n'

        if inv.root.file_id not in (None, ROOT_ID):

            e.set('file_id', inv.root.file_id)

        for path, ie in inv.iter_entries():

            e.append(self._pack_entry(ie))

        return e

    def _pack_entry(self, ie):

        """Convert InventoryEntry to XML element"""

        e = Element('entry')

        e.set('name', ie.name)

        e.set('file_id', ie.file_id)

        e.set('kind', ie.kind)

        if ie.text_size != None:

            e.set('text_size', '%d' % ie.text_size)

        for f in ['text_id', 'text_sha1']:

            v = getattr(ie, f)

            if v != None:

                e.set(f, v)

        # to be conservative, we don't externalize the root pointers

        # for now, leaving them as null in the xml form.  in a future

        # version it will be implied by nested elements.

        if ie.parent_id != ROOT_ID:

            assert isinstance(ie.parent_id, basestring)

            e.set('parent_id', ie.parent_id)

        e.tail = '\n'

        return e

    def _unpack_inventory(self, elt):

        """Construct from XML Element

        """

        assert elt.tag == 'inventory'

        root_id = elt.get('file_id') or ROOT_ID

        inv = Inventory(root_id)

        for e in elt:

            ie = self._unpack_entry(e)

            if ie.parent_id == ROOT_ID:

                ie.parent_id = root_id

            inv.add(ie)

        return inv

    def _unpack_entry(self, elt):

        assert elt.tag == 'entry'

        ## original format inventories don't have a parent_id for

        ## nodes in the root directory, but it's cleaner to use one

        ## internally.

        parent_id = elt.get('parent_id')

        if parent_id == None:

            parent_id = ROOT_ID

        ie = InventoryEntry(elt.get('file_id'),

                            elt.get('name'),

                            elt.get('kind'),

                            parent_id)

        ie.text_id = elt.get('text_id')

        ie.text_sha1 = elt.get('text_sha1')

        ## mutter("read inventoryentry: %r" % (elt.attrib))

        v = elt.get('text_size')

        ie.text_size = v and int(v)

        return ie

    def _pack_revision(self, rev):

        """Revision object -> xml tree"""

        root = Element('revision',

                       committer = rev.committer,

                       timestamp = '%.9f' % rev.timestamp,

                       revision_id = rev.revision_id,

                       inventory_id = rev.inventory_id,

                       inventory_sha1 = rev.inventory_sha1,

                       )

        if rev.timezone:

            root.set('timezone', str(rev.timezone))

        root.text = '\n'

        msg = SubElement(root, 'message')

        msg.text = rev.message

        msg.tail = '\n'

        if rev.parents:

            pelts = SubElement(root, 'parents')

            pelts.tail = pelts.text = '\n'

            for rr in rev.parents:

                assert isinstance(rr, RevisionReference)

                p = SubElement(pelts, 'revision_ref')

                p.tail = '\n'

                assert rr.revision_id

                p.set('revision_id', rr.revision_id)

                if rr.revision_sha1:

                    p.set('revision_sha1', rr.revision_sha1)

        return root

    def _unpack_revision(self, elt):

        """XML Element -> Revision object"""

        # <changeset> is deprecated...

        if elt.tag not in ('revision', 'changeset'):

            raise BzrError("unexpected tag in revision file: %r" % elt)

        rev = Revision(committer = elt.get('committer'),

                       timestamp = float(elt.get('timestamp')),

                       revision_id = elt.get('revision_id'),

                       inventory_id = elt.get('inventory_id'),

                       inventory_sha1 = elt.get('inventory_sha1')

                       )

        precursor = elt.get('precursor')

        precursor_sha1 = elt.get('precursor_sha1')

        pelts = elt.find('parents')

        if pelts:

            for p in pelts:

                assert p.tag == 'revision_ref', \

                       "bad parent node tag %r" % p.tag

                rev_ref = RevisionReference(p.get('revision_id'),

                                            p.get('revision_sha1'))

                rev.parents.append(rev_ref)

            if precursor:

                # must be consistent

                prec_parent = rev.parents[0].revision_id

                assert prec_parent == precursor

        elif precursor:

            # revisions written prior to 0.0.5 have a single precursor

            # give as an attribute

            rev_ref = RevisionReference(precursor, precursor_sha1)

            rev.parents.append(rev_ref)

        v = elt.get('timezone')

        rev.timezone = v and int(v)

        rev.message = elt.findtext('message') # text of <message>

        return rev

"""singleton instance"""

serializer_v4 = _Serializer_v4()