sdk/python/arvados/_normalize_stream.py

   1 # Copyright (C) The Arvados Authors. All rights reserved.
   2 #
   3 # SPDX-License-Identifier: Apache-2.0
   4
   5 from __future__ import absolute_import
   6 from . import config
   7
   8 import re
   9
  10 def escape(path):
  11     path = re.sub('\\\\', lambda m: '\\134', path)
  12     path = re.sub('[:\000-\040]', lambda m: "\\%03o" % ord(m.group(0)), path)
  13     return path
  14
  15 def normalize_stream(stream_name, stream):
  16     """Take manifest stream and return a list of tokens in normalized format.
  17
  18     :stream_name:
  19       The name of the stream.
  20
  21     :stream:
  22       A dict mapping each filename to a list of `_range.LocatorAndRange` objects.
  23
  24     """
  25
  26     stream_name = escape(stream_name)
  27     stream_tokens = [stream_name]
  28     sortedfiles = list(stream.keys())
  29     sortedfiles.sort()
  30
  31     blocks = {}
  32     streamoffset = 0
  33     # Go through each file and add each referenced block exactly once.
  34     for streamfile in sortedfiles:
  35         for segment in stream[streamfile]:
  36             if segment.locator not in blocks:
  37                 stream_tokens.append(segment.locator)
  38                 blocks[segment.locator] = streamoffset
  39                 streamoffset += segment.block_size
  40
  41     # Add the empty block if the stream is otherwise empty.
  42     if len(stream_tokens) == 1:
  43         stream_tokens.append(config.EMPTY_BLOCK_LOCATOR)
  44
  45     for streamfile in sortedfiles:
  46         # Add in file segments
  47         current_span = None
  48         fout = escape(streamfile)
  49         for segment in stream[streamfile]:
  50             # Collapse adjacent segments
  51             streamoffset = blocks[segment.locator] + segment.segment_offset
  52             if current_span is None:
  53                 current_span = [streamoffset, streamoffset + segment.segment_size]
  54             else:
  55                 if streamoffset == current_span[1]:
  56                     current_span[1] += segment.segment_size
  57                 else:
  58                     stream_tokens.append("{0}:{1}:{2}".format(current_span[0], current_span[1] - current_span[0], fout))
  59                     current_span = [streamoffset, streamoffset + segment.segment_size]
  60
  61         if current_span is not None:
  62             stream_tokens.append("{0}:{1}:{2}".format(current_span[0], current_span[1] - current_span[0], fout))
  63
  64         if not stream[streamfile]:
  65             stream_tokens.append("0:0:{0}".format(fout))
  66
  67     return stream_tokens