Class: Positioning::AdvisoryLock

Inherits:
Object
  • Object
show all
Defined in:
lib/positioning/advisory_lock.rb

Defined Under Namespace

Classes: Adapter

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(base_class, column) ⇒ AdvisoryLock

Returns a new instance of AdvisoryLock.



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# File 'lib/positioning/advisory_lock.rb', line 10

def initialize(base_class, column)
  @base_class = base_class
  @column = column.to_s

  @adapters = {
    "mysql2" => Adapter.new(
      initialise: -> {},
      aquire: -> { connection.execute "SELECT GET_LOCK(#{connection.quote(lock_name)}, -1)" },
      release: -> { connection.execute "SELECT RELEASE_LOCK(#{connection.quote(lock_name)})" }
    ),
    "postgresql" => Adapter.new(
      initialise: -> {},
      aquire: -> { connection.execute "SELECT pg_advisory_lock(#{lock_name.hex & 0x7FFFFFFFFFFFFFFF})" },
      release: -> { connection.execute "SELECT pg_advisory_unlock(#{lock_name.hex & 0x7FFFFFFFFFFFFFFF})" }
    ),
    "sqlite3" => Adapter.new(
      initialise: -> {
        FileUtils.mkdir_p "#{Dir.pwd}/tmp"
        filename = "#{Dir.pwd}/tmp/#{lock_name}.lock"
        @file ||= File.open filename, File::RDWR | File::CREAT, 0o644
      },
      aquire: -> {
        @file.flock File::LOCK_EX
      },
      release: -> {
        @file.flock File::LOCK_UN
      }
    )
  }

  @adapters.default = Adapter.new(initialise: -> {}, aquire: -> {}, release: -> {})

  adapter.initialise.call
end

Instance Attribute Details

#base_class ⇒ Object (readonly)

Returns the value of attribute base_class.



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# File 'lib/positioning/advisory_lock.rb', line 8

def base_class
  @base_class
end

Instance Method Details

#aquire(record) ⇒ Object Also known as: before_create, before_update, before_destroy 



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# File 'lib/positioning/advisory_lock.rb', line 45

def aquire(record)
  adapter.aquire.call
end

#release(record) ⇒ Object Also known as: after_commit, after_rollback 



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# File 'lib/positioning/advisory_lock.rb', line 49

def release(record)
  adapter.release.call
end