Class: Contrast::Agent::Assess::Policy::Propagator::Append

Inherits:
Base
  • Object
show all
Defined in:
lib/contrast/agent/assess/policy/propagator/append.rb

Overview

Propagation that results in all the tags of the source being applied to the end of the target. The target’s preexisting tags are unaffected beyond any merging of overlapping tags.

Class Method Summary collapse

Methods inherited from Base

find_source, tracked_value?

Class Method Details

.propagate(propagation_node, preshift, target) ⇒ Object

For the source, append its tags to the target. if the target length is greater than the source copy tags from the param to the target in chunks of param size or less if param is appended in space less than param length



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# File 'lib/contrast/agent/assess/policy/propagator/append.rb', line 18

def propagate propagation_node, preshift, target
  properties = Contrast::Agent::Assess::Tracker.properties(target)
  return unless properties

  sources = propagation_node.sources
  source1 = find_source(sources[0], preshift)
  # Some appends have two args. If they don't this is probably something
  # obnoxious, like String.*
  source2 = sources[1] ? find_source(sources[1], preshift) : source1

  # if the object and the return are the same length just copy the tags
  # from the object(since nothing from args was added to return)
  if source1.length == target.length
    properties.copy_from(source1, target, 0, propagation_node.untags)
  else
    # find original in the target, copy tags to the new position in
    # target
    original_start_index = target.index(source1)
    properties.copy_from(source1, target, original_start_index, propagation_node.untags)

    start = original_start_index + source1.length
    while start < target.length
      properties.copy_from(source2, target, start, propagation_node.untags)
      start += source2.length
      next unless start > target.length

      properties.tags_at(start - source2.length).each do |tag|
        tag.update_end(target.length)
      end
    end
  end
  properties.cleanup_tags
end