cvs2svn_lib/symbolings_reader.py

   1 # (Be in -*- python -*- mode.)
   2 #
   3 # ====================================================================
   4 # Copyright (c) 2000-2006 CollabNet.  All rights reserved.
   5 #
   6 # This software is licensed as described in the file COPYING, which
   7 # you should have received as part of this distribution.  The terms
   8 # are also available at http://subversion.tigris.org/license-1.html.
   9 # If newer versions of this license are posted there, you may use a
  10 # newer version instead, at your option.
  11 #
  12 # This software consists of voluntary contributions made by many
  13 # individuals.  For exact contribution history, see the revision
  14 # history and logs, available at http://cvs2svn.tigris.org/.
  15 # ====================================================================
  16
  17 """This module contains database facilities used by cvs2svn."""
  18
  19 import cPickle
  20
  21 from cvs2svn_lib.boolean import *
  22 from cvs2svn_lib import config
  23 from cvs2svn_lib.context import Ctx
  24 from cvs2svn_lib.artifact_manager import artifact_manager
  25 from cvs2svn_lib.database import Database
  26 from cvs2svn_lib.database import DB_OPEN_READ
  27 from cvs2svn_lib.openings_closings import OpeningsClosingsMap
  28 from cvs2svn_lib.symbol_filling_guide import SymbolFillingGuide
  29
  30
  31 class SymbolingsReader:
  32   """Provides an interface to the SYMBOL_OPENINGS_CLOSINGS_SORTED file
  33   and the SYMBOL_OFFSETS_DB.  Does the heavy lifting of finding and
  34   returning the correct opening and closing Subversion revision
  35   numbers for a given symbolic name."""
  36
  37   def __init__(self):
  38     """Opens the SYMBOL_OPENINGS_CLOSINGS_SORTED for reading, and
  39     reads the offsets database into memory."""
  40
  41     self.symbolings = open(
  42         artifact_manager.get_temp_file(
  43             config.SYMBOL_OPENINGS_CLOSINGS_SORTED),
  44         'r')
  45     # The offsets_db is really small, and we need to read and write
  46     # from it a fair bit, so suck it into memory
  47     offsets_db = file(
  48         artifact_manager.get_temp_file(config.SYMBOL_OFFSETS_DB), 'rb')
  49     # A map from symbol_id to offset.
  50     self.offsets = cPickle.load(offsets_db)
  51     offsets_db.close()
  52
  53   def filling_guide_for_symbol(self, symbol, svn_revnum):
  54     """Given SYMBOL and SVN_REVNUM, return a new SymbolFillingGuide object.
  55
  56     SYMBOL is a Symbol instance.  Note that if we encounter an opening
  57     rev in this fill, but the corresponding closing rev takes place
  58     later than SVN_REVNUM, the closing will not be passed to
  59     SymbolFillingGuide in this fill (and will be discarded when
  60     encountered in a later fill).  This is perfectly fine, because we
  61     can still do a valid fill without the closing--we always try to
  62     fill what we can as soon as we can."""
  63
  64     openings_closings_map = OpeningsClosingsMap(symbol)
  65
  66     # It's possible to have a branch start with a file that was added
  67     # on a branch
  68     if symbol.id in self.offsets:
  69       # Set our read offset for self.symbolings to the offset for this
  70       # symbol:
  71       self.symbolings.seek(self.offsets[symbol.id])
  72
  73       while True:
  74         fpos = self.symbolings.tell()
  75         line = self.symbolings.readline().rstrip()
  76         if not line:
  77           break
  78         id, revnum, type, branch_id, cvs_file_id = line.split()
  79         id = int(id, 16)
  80         cvs_file_id = int(cvs_file_id, 16)
  81         cvs_file = Ctx()._cvs_file_db.get_file(cvs_file_id)
  82         if branch_id == '*':
  83           svn_path = Ctx().project.make_trunk_path(cvs_file.cvs_path)
  84         else:
  85           branch_id = int(branch_id, 16)
  86           svn_path = Ctx().project.make_branch_path(
  87               Ctx()._symbol_db.get_name(branch_id), cvs_file.cvs_path)
  88         revnum = int(revnum)
  89         if revnum > svn_revnum or id != symbol.id:
  90           break
  91         openings_closings_map.register(svn_path, revnum, type)
  92
  93       # get current offset of the read marker and set it to the offset
  94       # for the beginning of the line we just read if we used anything
  95       # we read.
  96       if not openings_closings_map.is_empty():
  97         self.offsets[symbol.id] = fpos
  98
  99     return SymbolFillingGuide(openings_closings_map)
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