Class: Au::Diff

Inherits:
Object show all
Defined in:
lib/au/models/diff.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(id, parent_id, change, md5, db) ⇒ Diff

Returns a new instance of Diff.



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# File 'lib/au/models/diff.rb', line 51

def initialize(id, parent_id, change, md5, db)
  @id = id
  @parent_id = parent_id
  @change = change
  @md5 = md5
  @db = db
end

Instance Attribute Details

#change ⇒ Object (readonly)

Returns the value of attribute change.



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# File 'lib/au/models/diff.rb', line 49

def change
  @change
end

#db ⇒ Object (readonly)

Returns the value of attribute db.



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# File 'lib/au/models/diff.rb', line 49

def db
  @db
end

#id ⇒ Object (readonly)

Returns the value of attribute id.



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# File 'lib/au/models/diff.rb', line 49

def id
  @id
end

#md5 ⇒ Object (readonly)

Returns the value of attribute md5.



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# File 'lib/au/models/diff.rb', line 49

def md5
  @md5
end

#parent_id ⇒ Object (readonly)

Returns the value of attribute parent_id.



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# File 'lib/au/models/diff.rb', line 49

def parent_id
  @parent_id
end

Class Method Details

.create(db_name, parent_id, change, md5) ⇒ Object 



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# File 'lib/au/models/diff.rb', line 6

def self.create(db_name, parent_id, change, md5)
  db = get_db(db_name)
  id = Time.now.to_f
  db.transaction do
    db[id] = [parent_id, change, md5]
  end
  id
end

.find(id, db_name: nil, db: nil) ⇒ Object 



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# File 'lib/au/models/diff.rb', line 27

def self.find(id, db_name: nil, db: nil)
  raise 'Missing both db name and db' if db_name.nil? && db.nil?
  db ||= get_db(db_name)
  stored_values = db.transaction{ db[id] }

  raise 'Diff not found' unless stored_values
  parent_id, change, md5 = stored_values
  new(id, parent_id, change, md5, db)
end

.get_db(db_name) ⇒ Object

memoize all encountered dbs Note, may need to watch memory usage. Note, depending on PStore initialization, may not need this



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# File 'lib/au/models/diff.rb', line 40

def self.get_db(db_name)
  if @dbs
    @dbs[db_name] ||= PStore.new(db_name)
  else
    @dbs = {}
    get_db(db_name)
  end
end

.replay_changes_upto(id, db_name) ⇒ Object 



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# File 'lib/au/models/diff.rb', line 15

def self.replay_changes_upto(id, db_name)
  raise 'Missing block' unless block_given?
  diffs = [find(id, db_name: db_name)]
  while diffs.last.has_parent?
    diffs << diffs.last.parent
  end
  # apply the oldest first
  diffs.reverse.each do |diff|
    yield(diff)
  end
end

Instance Method Details

#has_parent? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/au/models/diff.rb', line 64

def has_parent?
  !!parent_id
end

#parent ⇒ Object 



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# File 'lib/au/models/diff.rb', line 59

def parent
  return unless parent_id
  self.class.find(parent_id, db: db)
end