Class: Familia::FieldType

Inherits:
Object
  • Object
show all
Defined in:
lib/familia/field_type.rb

Overview

Base class for all field types in Familia

Field types encapsulate the behavior for different kinds of fields, including how their getter/setter methods are defined and how values are serialized/deserialized.

Examples:

Creating a custom field type

class TimestampFieldType < Familia::FieldType
  def define_setter(klass)
    field_name = @name
    klass.define_method :"#{@method_name}=" do |value|
      timestamp = value.is_a?(Time) ? value.to_i : value
      instance_variable_set(:"@#{field_name}", timestamp)
    end
  end

  def define_getter(klass)
    field_name = @name
    klass.define_method @method_name do
      timestamp = instance_variable_get(:"@#{field_name}")
      timestamp ? Time.at(timestamp) : nil
    end
  end
end

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name, as: name, fast_method: :"#{name}!", on_conflict: :raise, loggable: true, **options) ⇒ FieldType

Initialize a new field type

Parameters:

  • name (Symbol) —

    The field name

  • as (Symbol, String, false) (defaults to: name) —

    The method name (defaults to field name) If false, no accessor methods are created

  • fast_method (Symbol, String, false) (defaults to: :"#{name}!") —

    The fast method name (defaults to "##name!"). If false, no fast method is created

  • on_conflict (Symbol) (defaults to: :raise) —

    Conflict resolution strategy when method already exists (:raise, :skip, :warn, :overwrite)

  • loggable (Boolean) (defaults to: true) —

    Whether this field should be included in serialization and logging operations (default: true)

  • options (Hash) —

    Additional options for the field type



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# File 'lib/familia/field_type.rb', line 49

def initialize(name, as: name, fast_method: :"#{name}!", on_conflict: :raise, loggable: true, **options)
  @name = name.to_sym
  @method_name = as == false ? nil : as.to_sym
  @fast_method_name = fast_method == false ? nil : fast_method&.to_sym

  # Validate fast method name format
  if @fast_method_name && !@fast_method_name.to_s.end_with?('!')
    raise ArgumentError, "Fast method name must end with '!' (got: #{@fast_method_name})"
  end

  @on_conflict = on_conflict
  @loggable = loggable
  @options = options
end

Instance Attribute Details

#fast_method_name ⇒ Object (readonly)

Returns the value of attribute fast_method_name.



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# File 'lib/familia/field_type.rb', line 32

def fast_method_name
  @fast_method_name
end

#loggable ⇒ Object (readonly)

Returns the value of attribute loggable.



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# File 'lib/familia/field_type.rb', line 32

def loggable
  @loggable
end

#method_name ⇒ Object (readonly)

Returns the value of attribute method_name.



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# File 'lib/familia/field_type.rb', line 32

def method_name
  @method_name
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/familia/field_type.rb', line 32

def name
  @name
end

#on_conflict ⇒ Object (readonly)

Returns the value of attribute on_conflict.



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# File 'lib/familia/field_type.rb', line 32

def on_conflict
  @on_conflict
end

#options ⇒ Object (readonly)

Returns the value of attribute options.



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# File 'lib/familia/field_type.rb', line 32

def options
  @options
end

Instance Method Details

#category ⇒ Symbol

The category for this field type (used for filtering)

Returns:

  • (Symbol) —

    the field category



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# File 'lib/familia/field_type.rb', line 230

def category
  :field
end

#define_fast_writer(klass) ⇒ Object

Define the fast writer method on the target class

Fast methods provide direct database access for immediate persistence. Subclasses can override this to customize fast method behavior.

Fields backing a class-level index are maintained fail-closed (#308): outside any transaction/pipeline the unique claim runs before the hash write (a conflict raises Familia::RecordExistsError and the hash is untouched); inside a caller's MULTI/pipeline no claim is possible, so the writer raises Familia::IndexedFieldFastWriteError rather than write the hash and leave the index stale. Should the hash write itself fail after the index was updated, the writer compensates best-effort before re-raising (see #compensate_failed_indexed_fast_write) -- the two commands are not one MULTI. Non-indexed fields are unaffected.

Parameters:

  • klass (Class) —

    The class to define the method on



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# File 'lib/familia/field_type.rb', line 150

def define_fast_writer(klass)
  return unless @fast_method_name&.to_s&.end_with?('!')

  field_name = @name
  fast_method_name = @fast_method_name
  field_type = self

  # Lives in the closure (not an ivar) because field types are frozen
  # after installation. One entry per runtime class, never pruned: safe
  # in practice because Horreum subclasses are a small static set for
  # the life of the process. It would only leak under unbounded dynamic
  # class creation (e.g. anonymous classes churned in a long-lived
  # process), where each discarded class leaves an entry that also pins
  # the class itself.
  index_rel_cache = {}.compare_by_identity

  handle_method_conflict(klass, fast_method_name) do
    klass.define_method fast_method_name do |*args|
      raise ArgumentError, "wrong number of arguments (given #{args.size}, expected 0 or 1)" if args.size > 1

      val = args.first

      # If no value provided, return current stored value
      # Handle Redis::Future objects during transactions
      return hget(field_name) if val.nil? || val.is_a?(Redis::Future)

      index_rels = field_type.send(:class_index_relationships, index_rel_cache, self.class)
      field_type.send(:guard_indexed_fast_write!, index_rels)

      # Trace the operation if debugging is enabled
      Familia.trace :FAST_WRITER, nil, "#{field_name}: #{val.inspect}" if Familia.debug?

      # Convert value for database storage
      prepared = serialize_value(val)
      Familia.debug "[FieldType#define_fast_writer] #{fast_method_name} val: #{val.class} prepared: #{prepared.class}"

      # Runs the setter, then claims and updates any class-level index
      # entries before the hash write below (ADR-0002 fail-closed
      # ordering). A claim conflict restores the in-memory state and
      # propagates typed, so the hash write never runs. For indexed
      # fields the rollback snapshot is returned (nil otherwise) so a
      # failed hash write below can be compensated.
      snapshot = field_type.send(:apply_fast_write_value, self, val, index_rels)

      begin
        # Persist to database immediately, compensating the index
        # entries above if the write fails (the two are separate
        # commands, not one MULTI -- see #persist_fast_write_value).
        ret = field_type.send(:persist_fast_write_value, self, prepared, val, index_rels, snapshot)

        # Touch instances timeline so the object is visible
        # to list-based enumeration (instances.to_a, count, etc.)
        touch_instances! if respond_to?(:touch_instances!)

        clear_dirty!(field_name) if respond_to?(:clear_dirty!)

        Familia.success?(ret)
      rescue Familia::Problem => e
        raise "#{fast_method_name} method failed: #{e.message}", e.backtrace
      end
    end
  end
end

#define_getter(klass) ⇒ Object

Define the getter method on the target class

Subclasses can override this to customize getter behavior. The default implementation creates a simple attr_reader equivalent.

Parameters:

  • klass (Class) —

    The class to define the method on



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# File 'lib/familia/field_type.rb', line 96

def define_getter(klass)
  field_name = @name
  method_name = @method_name

  handle_method_conflict(klass, method_name) do
    klass.define_method method_name do
      instance_variable_get(:"@#{field_name}")
    end
  end
end

#define_setter(klass) ⇒ Object

Note:

This setter only updates the in-memory instance variable. Call +save+, +commit_fields+, or use the fast_writer (+field_name!+) to persist to Redis.

Define the setter method on the target class

Subclasses can override this to customize setter behavior. The default implementation creates a simple attr_writer equivalent.

Parameters:

  • klass (Class) —

    The class to define the method on



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# File 'lib/familia/field_type.rb', line 118

def define_setter(klass)
  field_name = @name
  method_name = @method_name

  handle_method_conflict(klass, :"#{method_name}=") do
    klass.define_method :"#{method_name}=" do |value|
      old_value = instance_variable_get(:"@#{field_name}")
      instance_variable_set(:"@#{field_name}", value)

      # Track the change for dirty-tracking (only for Horreum instances)
      mark_dirty!(field_name, old_value) if respond_to?(:mark_dirty!)
    end
  end
end

#deserialize(value, _record = nil) ⇒ Object

Deserialize a value from database storage

Subclasses can override this to customize deserialization. The default implementation passes values through unchanged.

Parameters:

  • value (Object) —

    The value to deserialize

  • _record (Object) (defaults to: nil) —

    The record instance (for context)

Returns:

  • (Object) —

    The deserialized value



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# File 'lib/familia/field_type.rb', line 256

def deserialize(value, _record = nil)
  value
end

#generated_methods ⇒ Array<Symbol>

Returns all method names generated for this field (used for conflict detection)

Returns:

  • (Array<Symbol>) —

    Array of method names this field type generates



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# File 'lib/familia/field_type.rb', line 264

def generated_methods
  [@method_name, @fast_method_name].compact
end

#inspect ⇒ String Also known as: to_s

Enhanced inspection output for debugging

Returns:

  • (String) —

    Human-readable representation



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# File 'lib/familia/field_type.rb', line 272

def inspect
  attributes = [
    "name=#{@name}",
    "method_name=#{@method_name}",
    "fast_method_name=#{@fast_method_name}",
    "on_conflict=#{@on_conflict}",
    "category=#{category}",
  ]
  "#<#{self.class.name} #{attributes.join(' ')}>"
end

#install(klass) ⇒ Object

Install this field type on a class

This method defines all necessary methods on the target class and registers the field type for later reference.

Parameters:

  • klass (Class) —

    The class to install this field type on



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# File 'lib/familia/field_type.rb', line 71

def install(klass)
  if @method_name
    # For skip strategy, check for any method conflicts first
    if @on_conflict == :skip
      has_getter_conflict = klass.method_defined?(@method_name) || klass.private_method_defined?(@method_name)
      has_setter_conflict = klass.method_defined?(:"#{@method_name}=") || klass.private_method_defined?(:"#{@method_name}=")

      # If either getter or setter conflicts, skip the whole field
      return if has_getter_conflict || has_setter_conflict
    end

    define_getter(klass)
    define_setter(klass)
  end

  define_fast_writer(klass) if @fast_method_name
end

#persistent? ⇒ Boolean

Whether this field should be persisted to the database

Returns:

  • (Boolean) —

    true if field should be persisted



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# File 'lib/familia/field_type.rb', line 218

def persistent?
  true
end

#serialize(value, _record = nil) ⇒ Object

Serialize a value for database storage

Subclasses can override this to customize serialization. The default implementation passes values through unchanged.

Parameters:

  • value (Object) —

    The value to serialize

  • _record (Object) (defaults to: nil) —

    The record instance (for context)

Returns:

  • (Object) —

    The serialized value



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# File 'lib/familia/field_type.rb', line 243

def serialize(value, _record = nil)
  value
end

#transient? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/familia/field_type.rb', line 222

def transient?
  !persistent?
end