Class: Factbase::LazyTaped

Inherits:
Object
  • Object
show all
Defined in:
lib/factbase/lazy_taped.rb,
lib/factbase/lazy_taped_hash.rb,
lib/factbase/lazy_taped_array.rb

Overview

A lazy decorator of an Array with HashMaps that defers copying until modification.

Defined Under Namespace

Classes: LazyTapedArray, LazyTapedHash

Instance Method Summary collapse

Constructor Details

#initialize(origin) ⇒ LazyTaped

Returns a new instance of LazyTaped.



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# File 'lib/factbase/lazy_taped.rb', line 12

def initialize(origin)
  @origin = origin
  @staged = []
  @copied = false
  @copies = {}.compare_by_identity
  @inserted = []
  @deleted = []
  @added = []
end

Instance Method Details

#&(other) ⇒ Object 



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# File 'lib/factbase/lazy_taped.rb', line 109

def &(other)
  return Factbase::Taped.new([], inserted: @inserted, deleted: @deleted, added: @added) if other == []
  return Factbase::Taped.new([], inserted: @inserted, deleted: @deleted, added: @added) if empty?
  _join(other, &:&)
end

#<<(map) ⇒ Object 



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# File 'lib/factbase/lazy_taped.rb', line 67

def <<(map)
  @staged << map
  _track(map, map)
  @inserted.append(map.object_id)
end

#added ⇒ Object

Returns the unique object IDs of maps that were modified (properties added). This is used during transaction commit to track the churn (number of changes).



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# File 'lib/factbase/lazy_taped.rb', line 49

def added
  @added.uniq
end

#copied? ⇒ Boolean

Returns:



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# File 'lib/factbase/lazy_taped.rb', line 29

def copied?
  @copied
end

#delete_if ⇒ Object 



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# File 'lib/factbase/lazy_taped.rb', line 90

def delete_if
  ensure_copied!
  @staged.delete_if do |m|
    r = yield m
    @deleted.append(source_of(m).object_id) if r
    r
  end
end

#deleted ⇒ Object

Returns the unique object IDs of maps that were deleted. This is used during transaction commit to identify facts that need to be removed from the factbase.



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# File 'lib/factbase/lazy_taped.rb', line 43

def deleted
  @deleted.uniq
end

#each ⇒ Object 



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# File 'lib/factbase/lazy_taped.rb', line 73

def each
  return to_enum(__method__) unless block_given?
  yielded_size = 0
  is_copied = copied?
  unless is_copied
    @origin.each do |m|
      yield _tape(m)
      yielded_size += 1
    end
  end
  staged = is_copied == copied? ? @staged : @staged[yielded_size..]
  staged&.each do |f|
    next if f.nil?
    yield _tape(f)
  end
end

#empty? ⇒ Boolean

Returns:



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# File 'lib/factbase/lazy_taped.rb', line 63

def empty?
  copied? ? @staged.empty? : (@origin.empty? && @staged.empty?)
end

#ensure_copied! ⇒ Object 



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# File 'lib/factbase/lazy_taped.rb', line 121

def ensure_copied!
  return if copied?
  @staged = @origin.map do |o|
    o.transform_values(&:dup).tap { |c| _track(c, o) }
  end.concat(@staged)
  @copied = true
end

#find_by_object_id(oid) ⇒ Object 



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# File 'lib/factbase/lazy_taped.rb', line 53

def find_by_object_id(oid)
  r = @staged.find { |m| m.object_id == oid }
  r = @origin.find { |m| m.object_id == oid } if r.nil? && !copied?
  r
end

#get_copied_map(original_map) ⇒ Object 



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# File 'lib/factbase/lazy_taped.rb', line 129

def get_copied_map(original_map)
  ensure_copied!
  @copies[original_map] || original_map
end

#inserted ⇒ Object

Returns the unique object IDs of maps that were inserted (newly created). This is used during transaction commit to identify new facts that need to be added to the factbase.



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# File 'lib/factbase/lazy_taped.rb', line 36

def inserted
  @inserted.uniq
end

#repack(other) ⇒ Object 



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# File 'lib/factbase/lazy_taped.rb', line 103

def repack(other)
  ensure_copied!
  copied = other.map { |o| @copies[o] || o }
  Factbase::Taped.new(copied, inserted: @inserted, deleted: @deleted, added: @added)
end

#size ⇒ Object 



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# File 'lib/factbase/lazy_taped.rb', line 59

def size
  copied? ? @staged.size : (@origin.size + @staged.size)
end

#source_of(copy) ⇒ Object

Returns the original map this copy was derived from. Returns nil if the base hasn’t been copied yet or if the fact is new.



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# File 'lib/factbase/lazy_taped.rb', line 24

def source_of(copy)
  return nil unless @copied
  @copies.key(copy)
end

#to_a ⇒ Object 



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# File 'lib/factbase/lazy_taped.rb', line 99

def to_a
  (copied? ? @staged : (@origin + @staged)).to_a
end

#|(other) ⇒ Object 



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# File 'lib/factbase/lazy_taped.rb', line 115

def |(other)
  return Factbase::Taped.new(to_a, inserted: @inserted, deleted: @deleted, added: @added) if other == []
  return Factbase::Taped.new(other, inserted: @inserted, deleted: @deleted, added: @added) if empty?
  _join(other, &:|)
end