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