/brz/remove-bazaar

# Copyright (C) 2008 Canonical Ltd

#

# 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

"""Parser of import data into command objects.

In order to reuse existing front-ends, the stream format is a subset of

the one used by git-fast-import (as of the 1.5.4 release of git at least).

The grammar is:

  stream ::= cmd*;

  cmd ::= new_blob

        | new_commit

        | new_tag

        | reset_branch

        | checkpoint

        | progress

        ;

  new_blob ::= 'blob' lf

    mark?

    file_content;

  file_content ::= data;

  new_commit ::= 'commit' sp ref_str lf

    mark?

    ('author' sp name '<' email '>' when lf)?

    'committer' sp name '<' email '>' when lf

    commit_msg

    ('from' sp (ref_str | hexsha1 | sha1exp_str | idnum) lf)?

    ('merge' sp (ref_str | hexsha1 | sha1exp_str | idnum) lf)*

    file_change*

    lf?;

  commit_msg ::= data;

  file_change ::= file_clr

    | file_del

    | file_rnm

    | file_cpy

    | file_obm

    | file_inm;

  file_clr ::= 'deleteall' lf;

  file_del ::= 'D' sp path_str lf;

  file_rnm ::= 'R' sp path_str sp path_str lf;

  file_cpy ::= 'C' sp path_str sp path_str lf;

  file_obm ::= 'M' sp mode sp (hexsha1 | idnum) sp path_str lf;

  file_inm ::= 'M' sp mode sp 'inline' sp path_str lf

    data;

  new_tag ::= 'tag' sp tag_str lf

    'from' sp (ref_str | hexsha1 | sha1exp_str | idnum) lf

    'tagger' sp name '<' email '>' when lf

    tag_msg;

  tag_msg ::= data;

  reset_branch ::= 'reset' sp ref_str lf

    ('from' sp (ref_str | hexsha1 | sha1exp_str | idnum) lf)?

    lf?;

  checkpoint ::= 'checkpoint' lf

    lf?;

  progress ::= 'progress' sp not_lf* lf

    lf?;

     # note: the first idnum in a stream should be 1 and subsequent

     # idnums should not have gaps between values as this will cause

     # the stream parser to reserve space for the gapped values.  An

     # idnum can be updated in the future to a new object by issuing

     # a new mark directive with the old idnum.

     #

  mark ::= 'mark' sp idnum lf;

  data ::= (delimited_data | exact_data)

    lf?;

    # note: delim may be any string but must not contain lf.

    # data_line may contain any data but must not be exactly

    # delim.

  delimited_data ::= 'data' sp '<<' delim lf

    (data_line lf)*

    delim lf;

     # note: declen indicates the length of binary_data in bytes.

     # declen does not include the lf preceeding the binary data.

     #

  exact_data ::= 'data' sp declen lf

    binary_data;

     # note: quoted strings are C-style quoting supporting \c for

     # common escapes of 'c' (e..g \n, \t, \\, \") or \nnn where nnn

     # is the signed byte value in octal.  Note that the only

     # characters which must actually be escaped to protect the

     # stream formatting is: \, " and LF.  Otherwise these values

     # are UTF8.

     #

  ref_str     ::= ref;

  sha1exp_str ::= sha1exp;

  tag_str     ::= tag;

  path_str    ::= path    | '"' quoted(path)    '"' ;

  mode        ::= '100644' | '644'

                | '100755' | '755'

                | '120000'

                ;

  declen ::= # unsigned 32 bit value, ascii base10 notation;

  bigint ::= # unsigned integer value, ascii base10 notation;

  binary_data ::= # file content, not interpreted;

  when         ::= raw_when | rfc2822_when;

  raw_when     ::= ts sp tz;

  rfc2822_when ::= # Valid RFC 2822 date and time;

  sp ::= # ASCII space character;

  lf ::= # ASCII newline (LF) character;

     # note: a colon (':') must precede the numerical value assigned to

     # an idnum.  This is to distinguish it from a ref or tag name as

     # GIT does not permit ':' in ref or tag strings.

     #

  idnum   ::= ':' bigint;

  path    ::= # GIT style file path, e.g. "a/b/c";

  ref     ::= # GIT ref name, e.g. "refs/heads/MOZ_GECKO_EXPERIMENT";

  tag     ::= # GIT tag name, e.g. "FIREFOX_1_5";

  sha1exp ::= # Any valid GIT SHA1 expression;

  hexsha1 ::= # SHA1 in hexadecimal format;

     # note: name and email are UTF8 strings, however name must not

     # contain '<' or lf and email must not contain any of the

     # following: '<', '>', lf.

     #

  name  ::= # valid GIT author/committer name;

  email ::= # valid GIT author/committer email;

  ts    ::= # time since the epoch in seconds, ascii base10 notation;

  tz    ::= # GIT style timezone;

     # note: comments may appear anywhere in the input, except

     # within a data command.  Any form of the data command

     # always escapes the related input from comment processing.

     #

     # In case it is not clear, the '#' that starts the comment

     # must be the first character on that the line (an lf have

     # preceeded it).

     #

  comment ::= '#' not_lf* lf;

  not_lf  ::= # Any byte that is not ASCII newline (LF);

"""

import re

import sys

import commands

import dates

import errors

## Stream parsing ##

class LineBasedParser(object):

    def __init__(self, input):

        """A Parser that keeps track of line numbers.

        :param input: the file-like object to read from

        """

        self.input = input

        self.lineno = 0

        # Lines pushed back onto the input stream

        self._buffer = []

    def abort(self, exception, *args):

        """Raise an exception providing line number information."""

        raise exception(self.lineno, *args)

    def readline(self):

        """Get the next line including the newline or '' on EOF."""

        self.lineno += 1

        if self._buffer:

            return self._buffer.pop()

        else:

            return self.input.readline()

    def next_line(self):

        """Get the next line without the newline or None on EOF."""

        line = self.readline()

        if line:

            return line[:-1]

        else:

            return None

    def push_line(self, line):

        """Push line back onto the line buffer.

        :param line: the line with no trailing newline

        """

        self.lineno -= 1

        self._buffer.append(line + "\n")

    def read_bytes(self, count):

        """Read a given number of bytes from the input stream.

        Throws MissingBytes if the bytes are not found.

        Note: This method does not read from the line buffer.

        """

        lines = []

        left = count

        while left > 0:

            line = self.input.readline(left)

            if line:

                left -= len(line)

                lines.append(line)

            else:

                left = 0

        result = ''.join(lines)

        found = len(result)

        if found != count:

            self.abort(errors.MissingBytes, count, found)

        return result

    def read_until(self, terminator):

        """Read the input stream until the terminator is found.

        Throws MissingTerminator if the terminator is not found.

        Note: This method does not read from the line buffer.

        :return: the bytes read up to but excluding the terminator.

        """

        raise NotImplementedError(self.read_until)

# Regular expression used for parsing. (Note: The spec states that the name

# part should be non-empty but git-fast-export doesn't always do that so

# the first bit is \w*, not \w+.)

_WHO_AND_WHEN_RE = re.compile(r'(\w*) <(.+)> (.+)')

class ImportParser(LineBasedParser):

    def __init__(self, input, verbose=False, output=sys.stdout):

        """A Parser of import commands.

        :param input: the file-like object to read from

        :param verbose: display extra information of not

        :param output: the file-like object to write messages to (YAGNI?)

        """

        LineBasedParser.__init__(self, input)

        self.verbose = verbose

        self.output = output

        # We auto-detect the date format when a date is first encountered

        self.date_parser = None

    def iter_commands(self):

        """Iterator returning ImportCommand objects."""

        while True:

            line = self.next_line()

            if line is None:

                break

            elif len(line) == 0 or line.startswith('#'):

                continue

            # Search for commands in order of likelihood

            elif line.startswith('commit '):

                yield self._parse_commit(line[len('commit '):])

            elif line.startswith('blob'):

                yield self._parse_blob()

            elif line.startswith('progress '):

                yield commands.ProgressCommand(line[len('progress '):])

            elif line.startswith('reset '):

                yield self._parse_reset(line[len('reset '):])

            elif line.startswith('tag '):

                yield self._parse_tag(line[len('tag '):])

            elif line.startswith('checkpoint'):

                yield commands.CheckpointCommand()

            else:

                self.abort(errors.InvalidCommand, line)

    def iter_file_commands(self):

        """Iterator returning FileCommand objects.

        If an invalid file command is found, the line is silently

        pushed back and iteration ends.

        """

        while True:

            line = self.next_line()

            if line is None:

                break

            elif len(line) == 0 or line.startswith('#'):

                continue

            # Search for file commands in order of likelihood

            elif line.startswith('M '):

                yield self._parse_file_modify(line[2:])

            elif line.startswith('D '):

                path = self._path(line[2:])

                yield commands.FileDeleteCommand(path)

            elif line.startswith('R '):

                old, new = self._path_pair(line[2:])

                yield commands.FileRenameCommand(old, new)

            elif line.startswith('C '):

                src, dest = self._path_pair(line[2:])

                yield commands.FileRenameCommand(src, dest)

            elif line.startswith('deleteall'):

                yield commands.FileDeleteAllCommand()

            else:

                self.push_line(line)

                break

    def _parse_blob(self):

        """Parse a blob command."""

        mark = self._get_mark_if_any()

        data = self._get_data('blob')

        return commands.BlobCommand(mark, data)

    def _parse_commit(self, ref):

        """Parse a commit command."""

        mark = self._get_mark_if_any()

        author = self._get_user_info('commit', 'author', False)

        committer = self._get_user_info('commit', 'committer')

        message = self._get_data('commit', 'message')

        from_ = self._get_from()

        if from_ is not None:

            parents = [from_]

            while True:

                merge = self._get_merge()

                if merge is not None:

                    parents.append(merge)

                else:

                    break

        else:

            parents = []

        return commands.CommitCommand(ref, mark, author, committer, message,

            parents, self.iter_file_commands)

    def _parse_file_modify(self, info):

        """Parse a filemodify command within a commit.

        :param info: a string in the format "mode dataref path"

          (where dataref might be the hard-coded literal 'inline').

        """

        params = info.split(' ', 2)

        path = self._path(params[2])

        is_executable, is_symlink = self._mode(params[0])

        if is_symlink:

            kind = commands.SYMLINK_KIND

        else:

            kind = commands.FILE_KIND

        if params[1] == 'inline':

            dataref = None

            data = self._get_data('filemodify')

        else:

            dataref = params[1]

            data = None

        return commands.FileModifyCommand(path, kind, is_executable, dataref,

            data)

    def _parse_reset(self, ref):

        """Parse a reset command."""

        from_ = self._get_from()

        return commands.ResetCommand(ref, from_)

    def _parse_tag(self, name):

        """Parse a tag command."""

        from_ = self._get_from('tag')

        tagger = self._get_user_info('tag', 'tagger')

        message = self._get_data('tag', 'message')

        return commands.TagCommand(name, from_, tagger, message)

    def _get_mark_if_any(self):

        """Parse a mark section."""

        line = self.next_line()

        if line.startswith('mark :'):

            return line[len('mark :'):]

        else:

            self.push_line(line)

            return None

    def _get_from(self, required_for=None):

        """Parse a from section."""

        line = self.next_line()

        if line.startswith('from '):

            return line[len('from '):]

        elif required_for:

            self.abort(errors.MissingSection, required_for, 'from')

        else:

            self.push_line(line)

            return None

    def _get_merge(self):

        """Parse a merge section."""

        line = self.next_line()

        if line.startswith('merge '):

            return line[len('merge '):]

        else:

            self.push_line(line)

            return None

    def _get_user_info(self, cmd, section, required=True):

        """Parse a user section."""

        line = self.next_line()

        if line.startswith(section + ' '):

            return self._who_when(line[len(section + ' '):], cmd, section)

        elif required:

            self.abort(errors.MissingSection, cmd, section)

        else:

            self.push_line(line)

            return None

    def _get_data(self, required_for, section='data'):

        """Parse a data section."""

        line = self.next_line()

        if line.startswith('data '):

            rest = line[len('data '):]

            if rest.startswith('<<'):

                return self.read_until(rest[2:])

            else:

                size = int(rest)

                return self.read_bytes(size)

        else:

            self.abort(errors.MissingSection, required_for, section)

    def _who_when(self, s, cmd, section):

        """Parse who and when information from a string.

        :return: a tuple of (name,email,timestamp,timezone)

        """

        match = _WHO_AND_WHEN_RE.search(s)

        if match:

            datestr = match.group(3)

            if self.date_parser is None:

                # auto-detect the date format

                if len(datestr.split(' ')) == 2:

                    format = 'raw'

                elif datestr == 'now':

                    format = 'now'

                else:

                    format = 'rfc2822'

                self.date_parser = dates.DATE_PARSERS_BY_NAME[format]

            when = self.date_parser(datestr)

            return (match.group(1),match.group(2),when[0],when[1])

        else:

            self.abort(errors.BadFormat, cmd, section, s)

    def _path(self, s):

        """Parse a path."""

        # TODO: handle quoted paths

        return s

    def _path_pair(self, s):

        """Parse two paths separated by a space."""

        # TODO: handle quoted paths

        return tuple(s.split(' ', 1))

    def _mode(self, s):

        """Parse a file mode into executable and symlink flags.

        :return (is_executable, is_symlink)

        """

        # Note: Output from git-fast-export slightly different to spec

        if s in ['644', '100644', '0100644']:

            return False, False

        elif s in ['755', '100755', '0100755']:

            return True, False

        elif s in ['120000', '0120000']:

            return False, True

        else:

            self.abort(errors.BadFormat, 'filemodify', 'mode', s)