Class: Dis::Model::Data

Inherits:
Object
  • Object
show all
Defined in:
lib/dis/model/data.rb

Overview

Dis Model Data

Facilitates communication between the model and the storage, and holds any newly assigned data before the record is saved.

Instance Method Summary collapse

Constructor Details

#initialize(record, raw = nil) ⇒ Data

Returns a new instance of Data.



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# File 'lib/dis/model/data.rb', line 10

def initialize(record, raw = nil)
  @record = record
  @raw = raw
end

Instance Method Details

#==(other) ⇒ Object

Returns true if two Data objects represent the same data.



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# File 'lib/dis/model/data.rb', line 16

def ==(other)
  # TODO: This can be made faster by
  # comparing hashes for stored objects.
  other.read == read
end

#any? ⇒ Boolean

Returns true if data exists either in memory or in storage.

Returns:

  • (Boolean) 


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# File 'lib/dis/model/data.rb', line 23

def any?
  raw? || stored?
end

#changed? ⇒ Boolean

Will be true if data has been explicitely set.

Dis::Model::Data.new(record).changed? # => false
Dis::Model::Data.new(record, new_file).changed? # => true

Returns:

  • (Boolean) 


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# File 'lib/dis/model/data.rb', line 36

def changed?
  raw?
end

#content_length ⇒ Object

Returns the length of the data.



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# File 'lib/dis/model/data.rb', line 41

def content_length
  if raw? && raw.respond_to?(:length)
    raw.length
  else
    read.try(&:length).to_i
  end
end

#expire(hash) ⇒ Object

Expires a data object from the storage if it’s no longer being used by existing records. This is triggered from callbacks on the record whenever they are changed or destroyed.



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# File 'lib/dis/model/data.rb', line 52

def expire(hash)
  unless @record.class.where(
    @record.class.dis_attributes[:content_hash] => hash
  ).any?
    Dis::Storage.delete(storage_type, hash)
  end
end

#read ⇒ Object

Returns the data as a binary string.



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# File 'lib/dis/model/data.rb', line 28

def read
  @read ||= read_from(closest)
end

#store! ⇒ Object

Stores the data. Returns a hash of the content for reference.

Raises:



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# File 'lib/dis/model/data.rb', line 61

def store!
  raise Dis::Errors::NoDataError unless raw?

  Dis::Storage.store(storage_type, raw)
end