Class: Db::Sync::Diff

Inherits:
Object
  • Object
show all
Defined in:
lib/db/sync/diff.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(original, replace_with, pkey) ⇒ Diff

Returns a new instance of Diff.



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# File 'lib/db/sync/diff.rb', line 5

def initialize(original, replace_with, pkey)
  self.original = original.collect
  self.replace_with = replace_with.collect
  self.pkey = pkey
  check_items
end

Instance Attribute Details

#deletes ⇒ Object (readonly)

Returns the value of attribute deletes.



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# File 'lib/db/sync/diff.rb', line 3

def deletes
  @deletes
end

#inserts ⇒ Object (readonly)

Returns the value of attribute inserts.



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# File 'lib/db/sync/diff.rb', line 3

def inserts
  @inserts
end

#original ⇒ Object

Returns the value of attribute original.



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# File 'lib/db/sync/diff.rb', line 2

def original
  @original
end

#pkey ⇒ Object

Returns the value of attribute pkey.



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# File 'lib/db/sync/diff.rb', line 2

def pkey
  @pkey
end

#replace_with ⇒ Object

Returns the value of attribute replace_with.



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# File 'lib/db/sync/diff.rb', line 2

def replace_with
  @replace_with
end

#updates ⇒ Object (readonly)

Returns the value of attribute updates.



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# File 'lib/db/sync/diff.rb', line 3

def updates
  @updates
end

Class Method Details

.compare(item1, item2) ⇒ Object 



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# File 'lib/db/sync/diff.rb', line 70

def self.compare(item1, item2)
  result = item1.values <=> item2.values
  compare_count
  result
end

.compare_count ⇒ Object

TODO: remove, checks for number of comparisons



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# File 'lib/db/sync/diff.rb', line 77

def self.compare_count
end

Instance Method Details

#check_for_update(original_item, replace_item) ⇒ Object 



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# File 'lib/db/sync/diff.rb', line 52

def check_for_update(original_item, replace_item)
  return if original_item.nil? || replace_item.nil?
  changes = {}
  replace_item.each do |key, value|
    next if value == original_item[key]
    changes[key] = value
  end
  return if changes.blank?
  @updates << { key: original_item.slice(*pkey), changes: changes }
end

#check_items ⇒ Object 



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# File 'lib/db/sync/diff.rb', line 24

def check_items
  @inserts = []
  @deletes = []
  @updates = []
  original.rewind
  replace_with.rewind

  original_item = next_original_item
  replace_item = next_replace_item

  loop do
    cmp = compare(original_item, replace_item)
    if cmp == 0
      check_for_update(original_item, replace_item)
      original_item = next_original_item
      replace_item = next_replace_item
    elsif cmp > 0
      @inserts << replace_item
      replace_item = next_replace_item
    else
      @deletes << original_item.slice(*pkey)
      original_item = next_original_item
    end
    break if original_item.nil? && replace_item.nil?
  end
  nil
end

#compare(item1, item2) ⇒ Object 



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# File 'lib/db/sync/diff.rb', line 63

def compare(item1, item2)
  return 0 if item1.nil? && item2.nil?
  return -1 if item2.nil?
  return 1 if item1.nil?
  self.class.compare(item1.slice(*pkey), item2.slice(*pkey))
end

#next_original_item ⇒ Object 



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# File 'lib/db/sync/diff.rb', line 12

def next_original_item
  original.next
rescue StopIteration
  nil
end

#next_replace_item ⇒ Object 



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# File 'lib/db/sync/diff.rb', line 18

def next_replace_item
  replace_with.next
rescue StopIteration
  nil
end