# 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, incorporated herein by reference.

from node import bin, hex, nullid

from i18n import _

import util, error, revlog, encoding

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')

class appender:

    '''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)

class changelog(revlog.revlog):

    def __init__(self, opener):

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

    def delayupdate(self):

        "delay visibility of index updates to other readers"

        self._realopener = self.opener

        self.opener = self._delayopener

        self._delaycount = len(self)

        self._delaybuf = []

        self._delayname = None

    def finalize(self, tr):

        "finalize index updates"

        self.opener = self._realopener

        # move redirected index data back into place

        if self._delayname:

            util.rename(self._delayname + ".a", self._delayname)

        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 _delayopener(self, name, mode='r'):

        fp = self._realopener(name, mode)

        # only divert the index

        if not name == self.indexfile:

            return fp

        # if we're doing an initial clone, divert to another file

        if self._delaycount == 0:

            self._delayname = fp.name

            if not len(self):

                # make sure to truncate the file

                mode = mode.replace('a', 'w')

            return self._realopener(name + ".a", mode)

        # otherwise, divert to memory

        return appender(fp, self._delaybuf)

    def readpending(self, file):

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

        self.index = r.index

        self.nodemap = r.nodemap

        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._delayname = fp1.name

        if self._delayname:

            return True

        return False

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

        if self.opener == self._delayopener:

            return

        return 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 metadatas, 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), [], "", {'branch': 'default'})

        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])

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

        if len(extra_data) != 3:

            time = float(extra_data.pop(0))

            try:

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

                timezone = int(extra_data[0])

            except:

                timezone = 0

            extra = {}

        else:

            time, timezone, extra = extra_data

            time, timezone = float(time), int(timezone)

        if not extra.get('branch'):

            extra['branch'] = 'default'

        files = l[3:]

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

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

                  user, date=None, extra={}):

        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))

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

        if date:

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

        else:

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

        if extra and extra.get("branch") in ("default", ""):

            del extra["branch"]

        if 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)