# changelog.py - changelog class for mercurial

#

# Copyright 2005-2007 Matt Mackall <mpm@selenic.com>

#

# This software may be used and distributed according to the terms of the

# GNU General Public License version 2 or any later version.

from node import bin, hex, nullid

from i18n import _

import util, error, revlog, encoding

_defaultextra = {'branch': 'default'}

def _string_escape(text):

    """

    >>> d = {'nl': chr(10), 'bs': chr(92), 'cr': chr(13), 'nul': chr(0)}

    >>> s = "ab%(nl)scd%(bs)s%(bs)sn%(nul)sab%(cr)scd%(bs)s%(nl)s" % d

    >>> s

    'ab\\ncd\\\\\\\\n\\x00ab\\rcd\\\\\\n'

    >>> res = _string_escape(s)

    >>> s == res.decode('string_escape')

    True

    """

    # subset of the string_escape codec

    text = text.replace('\\', '\\\\').replace('\n', '\\n').replace('\r', '\\r')

    return text.replace('\0', '\\0')

def decodeextra(text):

    """

    >>> decodeextra(encodeextra({'foo': 'bar', 'baz': chr(0) + '2'}))

    {'foo': 'bar', 'baz': '\\x002', 'branch': 'default'}

    >>> decodeextra(encodeextra({'foo': 'bar', 'baz': chr(92) + chr(0) + '2'}))

    {'foo': 'bar', 'baz': '\\\\\\x002', 'branch': 'default'}

    """

    extra = _defaultextra.copy()

    for l in text.split('\0'):

        if l:

            if '\\0' in l:

                # fix up \0 without getting into trouble with \\0

                l = l.replace('\\\\', '\\\\\n')

                l = l.replace('\\0', '\0')

                l = l.replace('\n', '')

            k, v = l.decode('string_escape').split(':', 1)

            extra[k] = v

    return extra

def encodeextra(d):

    # keys must be sorted to produce a deterministic changelog entry

    items = [_string_escape('%s:%s' % (k, d[k])) for k in sorted(d)]

    return "\0".join(items)

class appender(object):

    '''the changelog index must be updated last on disk, so we use this class

    to delay writes to it'''

    def __init__(self, fp, buf):

        self.data = buf

        self.fp = fp

        self.offset = fp.tell()

        self.size = util.fstat(fp).st_size

    def end(self):

        return self.size + len("".join(self.data))

    def tell(self):

        return self.offset

    def flush(self):

        pass

    def close(self):

        self.fp.close()

    def seek(self, offset, whence=0):

        '''virtual file offset spans real file and data'''

        if whence == 0:

            self.offset = offset

        elif whence == 1:

            self.offset += offset

        elif whence == 2:

            self.offset = self.end() + offset

        if self.offset < self.size:

            self.fp.seek(self.offset)

    def read(self, count=-1):

        '''only trick here is reads that span real file and data'''

        ret = ""

        if self.offset < self.size:

            s = self.fp.read(count)

            ret = s

            self.offset += len(s)

            if count > 0:

                count -= len(s)

        if count != 0:

            doff = self.offset - self.size

            self.data.insert(0, "".join(self.data))

            del self.data[1:]

            s = self.data[0][doff:doff + count]

            self.offset += len(s)

            ret += s

        return ret

    def write(self, s):

        self.data.append(str(s))

        self.offset += len(s)

def delayopener(opener, target, divert, buf):

    def o(name, mode='r'):

        if name != target:

            return opener(name, mode)

        if divert:

            return opener(name + ".a", mode.replace('a', 'w'))

        # otherwise, divert to memory

        return appender(opener(name, mode), buf)

    return o

class changelog(revlog.revlog):

    def __init__(self, opener):

        revlog.revlog.__init__(self, opener, "00changelog.i")

        if self._initempty:

            # changelogs don't benefit from generaldelta

            self.version &= ~revlog.REVLOGGENERALDELTA

            self._generaldelta = False

        self._realopener = opener

        self._delayed = False

        self._divert = False

    def delayupdate(self):

        "delay visibility of index updates to other readers"

        self._delayed = True

        self._divert = (len(self) == 0)

        self._delaybuf = []

        self.opener = delayopener(self._realopener, self.indexfile,

                                  self._divert, self._delaybuf)

    def finalize(self, tr):

        "finalize index updates"

        self._delayed = False

        self.opener = self._realopener

        # move redirected index data back into place

        if self._divert:

            nfile = self.opener(self.indexfile + ".a")

            n = nfile.name

            nfile.close()

            util.rename(n, n[:-2])

        elif self._delaybuf:

            fp = self.opener(self.indexfile, 'a')

            fp.write("".join(self._delaybuf))

            fp.close()

            self._delaybuf = []

        # split when we're done

        self.checkinlinesize(tr)

    def readpending(self, file):

        r = revlog.revlog(self.opener, file)

        self.index = r.index

        self.nodemap = r.nodemap

        self._nodecache = r._nodecache

        self._chunkcache = r._chunkcache

    def writepending(self):

        "create a file containing the unfinalized state for pretxnchangegroup"

        if self._delaybuf:

            # make a temporary copy of the index

            fp1 = self._realopener(self.indexfile)

            fp2 = self._realopener(self.indexfile + ".a", "w")

            fp2.write(fp1.read())

            # add pending data

            fp2.write("".join(self._delaybuf))

            fp2.close()

            # switch modes so finalize can simply rename

            self._delaybuf = []

            self._divert = True

        if self._divert:

            return True

        return False

    def checkinlinesize(self, tr, fp=None):

        if not self._delayed:

            revlog.revlog.checkinlinesize(self, tr, fp)

    def read(self, node):

        """

        format used:

        nodeid\n        : manifest node in ascii

        user\n          : user, no \n or \r allowed

        time tz extra\n : date (time is int or float, timezone is int)

                        : extra is metadata, encoded and separated by '\0'

                        : older versions ignore it

        files\n\n       : files modified by the cset, no \n or \r allowed

        (.*)            : comment (free text, ideally utf-8)

        changelog v0 doesn't use extra

        """

        text = self.revision(node)

        if not text:

            return (nullid, "", (0, 0), [], "", _defaultextra)

        last = text.index("\n\n")

        desc = encoding.tolocal(text[last + 2:])

        l = text[:last].split('\n')

        manifest = bin(l[0])

        user = encoding.tolocal(l[1])

        tdata = l[2].split(' ', 2)

        if len(tdata) != 3:

            time = float(tdata[0])

            try:

                # various tools did silly things with the time zone field.

                timezone = int(tdata[1])

            except ValueError:

                timezone = 0

            extra = _defaultextra

        else:

            time, timezone = float(tdata[0]), int(tdata[1])

            extra = decodeextra(tdata[2])

        files = l[3:]

        return (manifest, user, (time, timezone), files, desc, extra)

    def add(self, manifest, files, desc, transaction, p1, p2,

                  user, date=None, extra=None):

        # Convert to UTF-8 encoded bytestrings as the very first

        # thing: calling any method on a localstr object will turn it

        # into a str object and the cached UTF-8 string is thus lost.

        user, desc = encoding.fromlocal(user), encoding.fromlocal(desc)

        user = user.strip()

        # An empty username or a username with a "\n" will make the

        # revision text contain two "\n\n" sequences -> corrupt

        # repository since read cannot unpack the revision.

        if not user:

            raise error.RevlogError(_("empty username"))

        if "\n" in user:

            raise error.RevlogError(_("username %s contains a newline")

                                    % repr(user))

        # strip trailing whitespace and leading and trailing empty lines

        desc = '\n'.join([l.rstrip() for l in desc.splitlines()]).strip('\n')

        if date:

            parseddate = "%d %d" % util.parsedate(date)

        else:

            parseddate = "%d %d" % util.makedate()

        if extra:

            branch = extra.get("branch")

            if branch in ("default", ""):

                del extra["branch"]

            elif branch in (".", "null", "tip"):

                raise error.RevlogError(_('the name \'%s\' is reserved')

                                        % branch)

        if extra:

            extra = encodeextra(extra)

            parseddate = "%s %s" % (parseddate, extra)

        l = [hex(manifest), user, parseddate] + sorted(files) + ["", desc]

        text = "\n".join(l)

        return self.addrevision(text, transaction, len(self), p1, p2)