Class: ViewModel::ActiveRecord::UpdateOperation

Inherits:
Object
  • Object
show all
Defined in:
lib/view_model/active_record/update_operation.rb

Defined Under Namespace

Classes: MutableReferencedCollection, ParentData, ReferencedCollectionMember

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(viewmodel, update_data, reparent_to: nil, reposition_to: nil) ⇒ UpdateOperation

Returns a new instance of UpdateOperation.



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# File 'lib/view_model/active_record/update_operation.rb', line 24

def initialize(viewmodel, update_data, reparent_to: nil, reposition_to: nil)
  self.viewmodel           = viewmodel
  self.update_data         = update_data
  self.association_updates = {}
  self.reparent_to         = reparent_to
  self.reposition_to       = reposition_to
  self.released_children   = []

  @run_state = RunState::Pending
  @changed_associations = []
  @built = false
end

Instance Attribute Details

#association_updates ⇒ Object

Returns the value of attribute association_updates.



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# File 'lib/view_model/active_record/update_operation.rb', line 15

def association_updates
  @association_updates
end

#released_children ⇒ Object

Returns the value of attribute released_children.



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# File 'lib/view_model/active_record/update_operation.rb', line 15

def released_children
  @released_children
end

#reparent_to ⇒ Object

Returns the value of attribute reparent_to.



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# File 'lib/view_model/active_record/update_operation.rb', line 15

def reparent_to
  @reparent_to
end

#reposition_to ⇒ Object

Returns the value of attribute reposition_to.



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# File 'lib/view_model/active_record/update_operation.rb', line 15

def reposition_to
  @reposition_to
end

#update_data ⇒ Object

Returns the value of attribute update_data.



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# File 'lib/view_model/active_record/update_operation.rb', line 15

def update_data
  @update_data
end

#viewmodel ⇒ Object

Returns the value of attribute viewmodel.



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# File 'lib/view_model/active_record/update_operation.rb', line 15

def viewmodel
  @viewmodel
end

Instance Method Details

#add_update(association_data, update) ⇒ Object 



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# File 'lib/view_model/active_record/update_operation.rb', line 273

def add_update(association_data, update)
  self.association_updates[association_data] = update
end

#build!(update_context) ⇒ Object

Recursively builds UpdateOperations for the associations in our UpdateData

Raises:



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# File 'lib/view_model/active_record/update_operation.rb', line 238

def build!(update_context)
  raise ViewModel::DeserializationError::Internal.new('Internal error: UpdateOperation cannot build a deferred update') if viewmodel.nil?
  return self if built?

  update_data.associations.each do |association_name, association_update_data|
    association_data = self.viewmodel.class._association_data(association_name)
    update =
      if association_data.collection?
        build_updates_for_collection_association(association_data, association_update_data, update_context)
      else
        build_update_for_single_association(association_data, association_update_data, update_context)
      end

    add_update(association_data, update)
  end

  update_data.referenced_associations.each do |association_name, reference_string|
    association_data = self.viewmodel.class._association_data(association_name)

    update =
      if association_data.through?
        build_updates_for_collection_referenced_association(association_data, reference_string, update_context)
      elsif association_data.collection?
        build_updates_for_collection_association(association_data, reference_string, update_context)
      else
        build_update_for_single_association(association_data, reference_string, update_context)
      end

    add_update(association_data, update)
  end

  @built = true
  self
end

#built? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/view_model/active_record/update_operation.rb', line 43

def built?
  @built
end

#propagate_tree_changes(association_data, child_changes) ⇒ Object 



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# File 'lib/view_model/active_record/update_operation.rb', line 228

def propagate_tree_changes(association_data, child_changes)
  if association_data.nested?
    viewmodel.nested_children_changed!     if child_changes.changed_nested_tree?
    viewmodel.referenced_children_changed! if child_changes.changed_referenced_children?
  elsif association_data.owned?
    viewmodel.referenced_children_changed! if child_changes.changed_owned_tree?
  end
end

#reference_only? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/view_model/active_record/update_operation.rb', line 47

def reference_only?
  update_data.reference_only? && reparent_to.nil? && reposition_to.nil?
end

#run!(deserialize_context:) ⇒ Object

Evaluate a built update tree, applying and saving changes to the models.



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# File 'lib/view_model/active_record/update_operation.rb', line 52

def run!(deserialize_context:)
  raise ViewModel::DeserializationError::Internal.new('Internal error: UpdateOperation run before build') unless built?

  case @run_state
  when RunState::Running
    raise ViewModel::DeserializationError::Internal.new('Internal error: Cycle found in running UpdateOperation')
  when RunState::Run
    return viewmodel
  end

  @run_state = RunState::Running

  model = viewmodel.model

  debug_name = "#{model.class.name}:#{model.id || '<new>'}"
  debug "-> #{debug_name}: Entering"

  model.class.transaction do
    # Run context and viewmodel hooks
    ViewModel::Callbacks.wrap_deserialize(viewmodel, deserialize_context: deserialize_context) do |hook_control|
      # update parent association
      if reparent_to.present?
        debug "-> #{debug_name}: Updating parent pointer to '#{reparent_to.viewmodel.class.view_name}:#{reparent_to.viewmodel.id}'"
        association = model.association(reparent_to.association_reflection.name)
        association.writer(reparent_to.viewmodel.model)
        debug "<- #{debug_name}: Updated parent pointer"
      end

      # update position
      if reposition_to.present?
        debug "-> #{debug_name}: Updating position to #{reposition_to}"
        viewmodel._list_attribute = reposition_to
      end

      # Visit attributes and associations as much as possible in the order
      # that they're declared in the view. We can visit attributes and
      # points-to associations before save, but points-from associations
      # must be visited after save.
      pre_save_members, post_save_members = viewmodel.class._members.values.partition do |member_data|
        !member_data.association? || member_data.pointer_location == :local
      end

      pre_save_members.each do |member_data|
        if member_data.association?
          next unless association_updates.include?(member_data)

          child_operation = association_updates[member_data]

          reflection = member_data.direct_reflection
          debug "-> #{debug_name}: Updating points-to association '#{reflection.name}'"

          association = model.association(reflection.name)
          new_target =
            if child_operation
              child_ctx = viewmodel.context_for_child(member_data.association_name, context: deserialize_context)
              child_viewmodel = child_operation.run!(deserialize_context: child_ctx)
              propagate_tree_changes(member_data, child_viewmodel.previous_changes)

              child_viewmodel.model
            end
          association.writer(new_target)
          debug "<- #{debug_name}: Updated points-to association '#{reflection.name}'"
        else
          attr_name = member_data.name
          next unless attributes.include?(attr_name)

          serialized_value = attributes[attr_name]
          # Note that the VM::AR deserialization tree asserts ownership over any
          # references it's provided, and so they're intentionally not passed on
          # to attribute deserialization for use by their `using:` viewmodels. A
          # (better?) alternative would be to provide them as reference-only
          # hashes, to indicate that no modification can be permitted.
          viewmodel.public_send("deserialize_#{attr_name}", serialized_value,
                                references: {},
                                deserialize_context: deserialize_context)
        end
      end

      # If a request makes no assertions about the model, we don't demand
      # that the current state of the model is valid. This permits making
      # edits to other models that refer to this model when this model is
      # invalid.
      unless reference_only? && !viewmodel.new_model?
        deserialize_context.run_callback(ViewModel::Callbacks::Hook::BeforeValidate, viewmodel)
        viewmodel.validate!
      end

      # Save if the model has been altered. Covers not only models with
      # view changes but also lock version assertions.
      if viewmodel.model.changed? || viewmodel.model.new_record?
        debug "-> #{debug_name}: Saving"
        begin
          model.save!
        rescue ::ActiveRecord::RecordInvalid => ex
          raise ViewModel::DeserializationError::Validation.from_active_model(ex.errors, blame_reference)
        rescue ::ActiveRecord::StaleObjectError => _ex
          raise ViewModel::DeserializationError::LockFailure.new(blame_reference)
        end
        debug "<- #{debug_name}: Saved"
      end

      # Update association cache of pointed-from associations after save: the
      # child update will have saved the pointer.
      post_save_members.each do |association_data|
        next unless association_updates.include?(association_data)

        child_operation = association_updates[association_data]
        reflection = association_data.direct_reflection

        debug "-> #{debug_name}: Updating pointed-to association '#{reflection.name}'"

        association = model.association(reflection.name)
        child_ctx = viewmodel.context_for_child(association_data.association_name, context: deserialize_context)

        new_target =
          if child_operation
            ViewModel::Utils.map_one_or_many(child_operation) do |op|
              child_viewmodel = op.run!(deserialize_context: child_ctx)
              propagate_tree_changes(association_data, child_viewmodel.previous_changes)

              child_viewmodel.model
            end
          end

        association.target = new_target

        debug "<- #{debug_name}: Updated pointed-to association '#{reflection.name}'"
      end

      if self.released_children.present?
        # Released children that were not reclaimed by other parents during the
        # build phase will be deleted: check access control.
        debug "-> #{debug_name}: Checking released children permissions"
        self.released_children.reject(&:claimed?).each do |released_child|
          debug "-> #{debug_name}: Checking #{released_child.viewmodel.to_reference}"
          child_vm = released_child.viewmodel
          child_association_data = released_child.association_data
          child_ctx = viewmodel.context_for_child(child_association_data.association_name, context: deserialize_context)

          ViewModel::Callbacks.wrap_deserialize(child_vm, deserialize_context: child_ctx) do |child_hook_control|
            changes = ViewModel::Changes.new(deleted: true)
            child_ctx.run_callback(ViewModel::Callbacks::Hook::OnChange,
                                   child_vm,
                                   changes: changes)
            child_hook_control.record_changes(changes)
          end

          if child_association_data.nested?
            viewmodel.nested_children_changed!
          elsif child_association_data.owned?
            viewmodel.referenced_children_changed!
          end
        end
        debug "<- #{debug_name}: Finished checking released children permissions"
      end

      final_changes = viewmodel.clear_changes!

      if final_changes.changed?
        # Now that the change has been fully attempted, call the OnChange
        # hook if local changes were made
        deserialize_context.run_callback(ViewModel::Callbacks::Hook::OnChange, viewmodel, changes: final_changes)
      end

      hook_control.record_changes(final_changes)
    end
  end

  debug "<- #{debug_name}: Leaving"

  @run_state = RunState::Run
  viewmodel
rescue ::ActiveRecord::StatementInvalid, ::ActiveRecord::InvalidForeignKey, ::ActiveRecord::RecordNotSaved => ex
  raise ViewModel::DeserializationError::DatabaseConstraint.from_exception(ex, blame_reference)
end

#viewmodel_reference ⇒ Object 



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# File 'lib/view_model/active_record/update_operation.rb', line 37

def viewmodel_reference
  unless viewmodel.model.new_record?
    viewmodel.to_reference
  end
end