/brz/remove-bazaar

# Copyright (C) 2009 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

"""Map from Git sha's to Bazaar objects."""

from dulwich.objects import (

    sha_to_hex,

    hex_to_sha,

    )

import os

import threading

import bzrlib

from bzrlib import (

    registry,

    trace,

    )

from bzrlib.transport import (

    get_transport,

    )

def get_cache_dir():

    try:

        from xdg.BaseDirectory import xdg_cache_home

    except ImportError:

        from bzrlib.config import config_dir

        ret = os.path.join(config_dir(), "git")

    else:

        ret = os.path.join(xdg_cache_home, "bazaar", "git")

    if not os.path.isdir(ret):

        os.makedirs(ret)

    return ret

def get_remote_cache_transport():

    return get_transport(get_cache_dir())

def check_pysqlite_version(sqlite3):

    """Check that sqlite library is compatible.

    """

    if (sqlite3.sqlite_version_info[0] < 3 or

            (sqlite3.sqlite_version_info[0] == 3 and

             sqlite3.sqlite_version_info[1] < 3)):

        trace.warning('Needs at least sqlite 3.3.x')

        raise bzrlib.errors.BzrError("incompatible sqlite library")

try:

    try:

        import sqlite3

        check_pysqlite_version(sqlite3)

    except (ImportError, bzrlib.errors.BzrError), e:

        from pysqlite2 import dbapi2 as sqlite3

        check_pysqlite_version(sqlite3)

except:

    trace.warning('Needs at least Python2.5 or Python2.4 with the pysqlite2 '

            'module')

    raise bzrlib.errors.BzrError("missing sqlite library")

_mapdbs = threading.local()

def mapdbs():

    """Get a cache for this thread's db connections."""

    try:

        return _mapdbs.cache

    except AttributeError:

        _mapdbs.cache = {}

        return _mapdbs.cache

class GitShaMap(object):

    """Git<->Bzr revision id mapping database."""

    def lookup_git_sha(self, sha):

        """Lookup a Git sha in the database.

        :param sha: Git object sha

        :return: (type, type_data) with type_data:

            revision: revid, tree sha

        """

        raise NotImplementedError(self.lookup_git_sha)

    def lookup_blob_id(self, file_id, revision):

        """Retrieve a Git blob SHA by file id.

        :param file_id: File id of the file/symlink

        :param revision: revision in which the file was last changed.

        """

        raise NotImplementedError(self.lookup_blob_id)

    def lookup_tree_id(self, file_id, revision):

        """Retrieve a Git tree SHA by file id.

        """

        raise NotImplementedError(self.lookup_tree_id)

    def revids(self):

        """List the revision ids known."""

        raise NotImplementedError(self.revids)

    def missing_revisions(self, revids):

        """Return set of all the revisions that are not present."""

        present_revids = set(self.revids())

        if not isinstance(revids, set):

            revids = set(revids)

        return revids - present_revids

    def sha1s(self):

        """List the SHA1s."""

        raise NotImplementedError(self.sha1s)

    def start_write_group(self):

        """Start writing changes."""

    def commit_write_group(self):

        """Commit any pending changes."""

    def abort_write_group(self):

        """Abort any pending changes."""

class ContentCache(object):

    """Object that can cache Git objects."""

    def __getitem__(self, sha):

        """Retrieve an item, by SHA."""

        raise NotImplementedError(self.__getitem__)

class BzrGitCacheFormat(object):

    def get_format_string(self):

        """Return a single-line unique format string for this cache format."""

        raise NotImplementedError(self.get_format_string)

    def open(self, transport):

        """Open this format on a transport."""

        raise NotImplementedError(self.open)

    def initialize(self, transport):

        transport.put_bytes('format', self.get_format_string())

    @classmethod

    def from_transport(self, transport):

        """Open a cache file present on a transport, or initialize one.

        :param transport: Transport to use

        :return: A BzrGitCache instance

        """

        try:

            format_name = transport.get_bytes('format')

            format = formats.get(format_name)

        except bzrlib.errors.NoSuchFile:

            format = formats.get('default')

            format.initialize(transport)

        return format.open(transport)

    @classmethod

    def from_repository(cls, repository):

        """Open a cache file for a repository.

        This will use the repository's transport to store the cache file, or

        use the users global cache directory if the repository has no 

        transport associated with it.

        :param repository: Repository to open the cache for

        :return: A `BzrGitCache`

        """

        repo_transport = getattr(repository, "_transport", None)

        if repo_transport is not None:

            # Even if we don't write to this repo, we should be able 

            # to update its cache.

            repo_transport = remove_readonly_transport_decorator(repo_transport)

            try:

                repo_transport.mkdir('git')

            except bzrlib.errors.FileExists:

                pass

            transport = repo_transport.clone('git')

        else:

            transport = get_remote_cache_transport()

        return cls.from_transport(transport)

class CacheUpdater(object):

    def add_object(self, obj, ie):

        raise NotImplementedError(self.add_object)

    def finish(self):

        raise NotImplementedError(self.finish)

class BzrGitCache(object):

    """Caching backend."""

    def __init__(self, idmap, content_cache, cache_updater_klass):

        self.idmap = idmap

        self.content_cache = content_cache

        self._cache_updater_klass = cache_updater_klass

    def get_updater(self, rev):

        return self._cache_updater_klass(self, rev)

DictBzrGitCache = lambda: BzrGitCache(DictGitShaMap(), None, DictCacheUpdater)

class DictCacheUpdater(CacheUpdater):

    def __init__(self, cache, rev):

        self.cache = cache

        self.revid = rev.revision_id

        self.parent_revids = rev.parent_ids

        self._commit = None

        self._entries = []

    def add_object(self, obj, ie):

        if obj.type_name == "commit":

            self._commit = obj

            assert ie is None

            type_data = (self.revid, self._commit.tree)

            self.cache.idmap._by_revid[self.revid] = obj.id

        elif obj.type_name in ("blob", "tree"):

            if obj.type_name == "blob":

                revision = ie.revision

            else:

                revision = self.revid

            type_data = (ie.file_id, revision)

            self.cache.idmap._by_fileid.setdefault(type_data[1], {})[type_data[0]] = obj.id

        else:

            raise AssertionError

        self.cache.idmap._by_sha[obj.id] = (obj.type_name, type_data)

    def finish(self):

        if self._commit is None:

            raise AssertionError("No commit object added")

        return self._commit

class DictGitShaMap(GitShaMap):

    def __init__(self):

        self._by_sha = {}

        self._by_fileid = {}

        self._by_revid = {}

    def lookup_blob_id(self, fileid, revision):

        return self._by_fileid[revision][fileid]

    def lookup_git_sha(self, sha):

        return self._by_sha[sha]

    def lookup_tree_id(self, fileid, revision):

        return self._by_fileid[revision][fileid]

    def lookup_commit(self, revid):

        return self._by_revid[revid]

    def revids(self):

        for key, (type, type_data) in self._by_sha.iteritems():

            if type == "commit":

                yield type_data[0]

    def sha1s(self):

        return self._by_sha.iterkeys()

class SqliteCacheUpdater(CacheUpdater):

    def __init__(self, cache, rev):

        self.cache = cache

        self.db = self.cache.idmap.db

        self.revid = rev.revision_id

        self._commit = None

        self._trees = []

        self._blobs = []

    def add_object(self, obj, ie):

        if obj.type_name == "commit":

            self._commit = obj

            assert ie is None

        elif obj.type_name == "tree":

            self._trees.append((obj.id, ie.file_id, self.revid))

        elif obj.type_name == "blob":

            self._blobs.append((obj.id, ie.file_id, ie.revision))

        else:

            raise AssertionError

    def finish(self):

        if self._commit is None:

            raise AssertionError("No commit object added")

        self.db.executemany(

            "replace into trees (sha1, fileid, revid) values (?, ?, ?)",

            self._trees)

        self.db.executemany(

            "replace into blobs (sha1, fileid, revid) values (?, ?, ?)",

            self._blobs)

        self.db.execute(

            "replace into commits (sha1, revid, tree_sha) values (?, ?, ?)",

            (self._commit.id, self.revid, self._commit.tree))

        return self._commit

SqliteBzrGitCache = lambda p: BzrGitCache(SqliteGitShaMap(p), None, SqliteCacheUpdater)

class SqliteGitCacheFormat(BzrGitCacheFormat):

    def get_format_string(self):

        return 'bzr-git sha map version 1 using sqlite\n'

    def open(self, transport):

        try:

            basepath = transport.local_abspath(".")

        except bzrlib.errors.NotLocalUrl:

            basepath = get_cache_dir()

        return SqliteBzrGitCache(os.path.join(basepath, "idmap.db"))

class SqliteGitShaMap(GitShaMap):

    def __init__(self, path=None):

        self.path = path

        if path is None:

            self.db = sqlite3.connect(":memory:")

        else:

            if not mapdbs().has_key(path):

                mapdbs()[path] = sqlite3.connect(path)

            self.db = mapdbs()[path]

        self.db.text_factory = str

        self.db.executescript("""

        create table if not exists commits(

            sha1 text not null check(length(sha1) == 40),

            revid text not null,

            tree_sha text not null check(length(tree_sha) == 40)

        );

        create index if not exists commit_sha1 on commits(sha1);

        create unique index if not exists commit_revid on commits(revid);

        create table if not exists blobs(

            sha1 text not null check(length(sha1) == 40),

            fileid text not null,

            revid text not null

        );

        create index if not exists blobs_sha1 on blobs(sha1);

        create unique index if not exists blobs_fileid_revid on blobs(fileid, revid);

        create table if not exists trees(

            sha1 text unique not null check(length(sha1) == 40),

            fileid text not null,

            revid text not null

        );

        create unique index if not exists trees_sha1 on trees(sha1);

        create unique index if not exists trees_fileid_revid on trees(fileid, revid);

""")

    def __repr__(self):

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

    def lookup_commit(self, revid):

        row = self.db.execute("select sha1 from commits where revid = ?", (revid,)).fetchone()

        if row is not None:

            return row[0]

        raise KeyError

    def commit_write_group(self):

        self.db.commit()

    def lookup_blob_id(self, fileid, revision):

        row = self.db.execute("select sha1 from blobs where fileid = ? and revid = ?", (fileid, revision)).fetchone()

        if row is not None:

            return row[0]

        raise KeyError(fileid)

    def lookup_tree_id(self, fileid, revision):

        row = self.db.execute("select sha1 from trees where fileid = ? and revid = ?", (fileid, revision)).fetchone()

        if row is not None:

            return row[0]

        raise KeyError(fileid)

    def lookup_git_sha(self, sha):

        """Lookup a Git sha in the database.

        :param sha: Git object sha

        :return: (type, type_data) with type_data:

            revision: revid, tree sha

        """

        row = self.db.execute("select revid, tree_sha from commits where sha1 = ?", (sha,)).fetchone()

        if row is not None:

            return ("commit", row)

        row = self.db.execute("select fileid, revid from blobs where sha1 = ?", (sha,)).fetchone()

        if row is not None:

            return ("blob", row)

        row = self.db.execute("select fileid, revid from trees where sha1 = ?", (sha,)).fetchone()

        if row is not None:

            return ("tree", row)

        raise KeyError(sha)

    def revids(self):

        """List the revision ids known."""

        return (row for (row,) in self.db.execute("select revid from commits"))

    def sha1s(self):

        """List the SHA1s."""

        for table in ("blobs", "commits", "trees"):

            for (sha,) in self.db.execute("select sha1 from %s" % table):

                yield sha

class TdbCacheUpdater(CacheUpdater):

    def __init__(self, cache, rev):

        self.cache = cache

        self.db = cache.idmap.db

        self.revid = rev.revision_id

        self.parent_revids = rev.parent_ids

        self._commit = None

        self._entries = []

    def add_object(self, obj, ie):

        sha = obj.sha().digest()

        if obj.type_name == "commit":

            self.db["commit\0" + self.revid] = "\0".join((sha, obj.tree))

            type_data = (self.revid, obj.tree)

            self._commit = obj

            assert ie is None

        elif obj.type_name == "blob":

            self.db["\0".join(("blob", ie.file_id, ie.revision))] = sha

            type_data = (ie.file_id, ie.revision)

        elif obj.type_name == "tree":

            type_data = (ie.file_id, self.revid)

        else:

            raise AssertionError

        self.db["git\0" + sha] = "\0".join((obj.type_name, ) + type_data)

    def finish(self):

        if self._commit is None:

            raise AssertionError("No commit object added")

        return self._commit

TdbBzrGitCache = lambda p: BzrGitCache(TdbGitShaMap(p), None, TdbCacheUpdater)

class TdbGitCacheFormat(BzrGitCacheFormat):

    def get_format_string(self):

        return 'bzr-git sha map version 3 using tdb\n'

    def open(self, transport):

        try:

            basepath = transport.local_abspath(".")

        except bzrlib.errors.NotLocalUrl:

            basepath = get_cache_dir()

        try:

            return TdbBzrGitCache(os.path.join(basepath, "idmap.tdb"))

        except ImportError:

            raise ImportError(

                "Unable to open existing bzr-git cache because 'tdb' is not "

                "installed.")

class TdbGitShaMap(GitShaMap):

    """SHA Map that uses a TDB database.

    Entries:

    "git <sha1>" -> "<type> <type-data1> <type-data2>"

    "commit revid" -> "<sha1> <tree-id>"

    "tree fileid revid" -> "<sha1>"

    "blob fileid revid" -> "<sha1>"

    """

    TDB_MAP_VERSION = 3

    TDB_HASH_SIZE = 50000

    def __init__(self, path=None):

        import tdb

        self.path = path

        if path is None:

            self.db = {}

        else:

            if not mapdbs().has_key(path):

                mapdbs()[path] = tdb.Tdb(path, self.TDB_HASH_SIZE, tdb.DEFAULT,

                                          os.O_RDWR|os.O_CREAT)

            self.db = mapdbs()[path]

        try:

            if int(self.db["version"]) not in (2, 3):

                trace.warning("SHA Map is incompatible (%s -> %d), rebuilding database.",

                              self.db["version"], self.TDB_MAP_VERSION)

                self.db.clear()

        except KeyError:

            pass

        self.db["version"] = str(self.TDB_MAP_VERSION)

    def start_write_group(self):

        """Start writing changes."""

        self.db.transaction_start()

    def commit_write_group(self):

        """Commit any pending changes."""

        self.db.transaction_commit()

    def abort_write_group(self):

        """Abort any pending changes."""

        self.db.transaction_cancel()

    def __repr__(self):

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

    def lookup_commit(self, revid):

        return sha_to_hex(self.db["commit\0" + revid][:20])

    def lookup_blob_id(self, fileid, revision):

        return sha_to_hex(self.db["\0".join(("blob", fileid, revision))])

    def lookup_git_sha(self, sha):

        """Lookup a Git sha in the database.

        :param sha: Git object sha

        :return: (type, type_data) with type_data:

            revision: revid, tree sha

        """

        if len(sha) == 40:

            sha = hex_to_sha(sha)

        data = self.db["git\0" + sha].split("\0")

        return (data[0], (data[1], data[2]))

    def missing_revisions(self, revids):

        ret = set()

        for revid in revids:

            if self.db.get("commit\0" + revid) is None:

                ret.add(revid)

        return ret

    def revids(self):

        """List the revision ids known."""

        for key in self.db.iterkeys():

            if key.startswith("commit\0"):

                yield key[7:]

    def sha1s(self):

        """List the SHA1s."""

        for key in self.db.iterkeys():

            if key.startswith("git\0"):

                yield sha_to_hex(key[4:])

formats = registry.Registry()

formats.register(TdbGitCacheFormat().get_format_string(),

    TdbGitCacheFormat())

formats.register(SqliteGitCacheFormat().get_format_string(),

    SqliteGitCacheFormat())

try:

    import tdb

except ImportError:

    formats.register('default', SqliteGitCacheFormat())

else:

    formats.register('default', TdbGitCacheFormat())

def migrate_ancient_formats(repo_transport):

    # Prefer migrating git.db over git.tdb, since the latter may not 

    # be openable on some platforms.

    if repo_transport.has("git.db"):

        SqliteGitCacheFormat().initialize(repo_transport.clone("git"))

        repo_transport.rename("git.db", "git/idmap.db")

    elif repo_transport.has("git.tdb"):

        TdbGitCacheFormat().initialize(repo_transport.clone("git"))

        repo_transport.rename("git.tdb", "git/idmap.tdb")

def remove_readonly_transport_decorator(transport):

    if transport.is_readonly():

        return transport._decorated

    return transport

def from_repository(repository):

    """Open a cache file for a repository.

    If the repository is remote and there is no transport available from it

    this will use a local file in the users cache directory

    (typically ~/.cache/bazaar/git/)

    :param repository: A repository object

    """

    repo_transport = getattr(repository, "_transport", None)

    if repo_transport is not None:

        # Migrate older cache formats

        repo_transport = remove_readonly_transport_decorator(repo_transport)

        try:

            repo_transport.mkdir("git")

        except bzrlib.errors.FileExists:

            pass

        else:

            migrate_ancient_formats(repo_transport)

    return BzrGitCacheFormat.from_repository(repository)