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# frozen-string-literal: true
module Sequel
module Plugins
# The instance_hooks plugin allows you to add hooks to specific instances,
# by passing a block to a _hook method (e.g. before_save_hook{do_something}).
# The block is executed when the hook is called (e.g. before_save).
#
# All of the standard hooks are supported.
# Instance level before hooks are executed in reverse order of addition before
# calling super. Instance level after hooks are executed in order of addition
# after calling super.
#
# Instance level hooks for before and after are cleared after all related
# after level instance hooks have run. This means that if you add a before_create
# and before_update instance hooks to a new object, the before_create hook will
# be run the first time you save the object (creating it), and the before_update
# hook will be run the second time you save the object (updating it), and no
# hooks will be run the third time you save the object.
#
# Validation hooks are not cleared until after a successful save.
#
# Usage:
#
# # Add the instance hook methods to all model subclass instances (called before loading subclasses)
# Sequel::Model.plugin :instance_hooks
#
# # Add the instance hook methods just to Album instances
# Album.plugin :instance_hooks
module InstanceHooks
module InstanceMethods
Sequel::Model::HOOKS.each{|h| class_eval(<<-END , __FILE__, __LINE__+1)}
def #{h}_hook(&block)
raise Sequel::Error, "can't add hooks to frozen object" if frozen?
add_instance_hook(:#{h}, &block)
self
end
END
[:before_create, :before_update, :before_validation].each{|h| class_eval("def #{h}; run_before_instance_hooks(:#{h}) if @instance_hooks; super end", __FILE__, __LINE__)}
[:after_create, :after_update].each{|h| class_eval(<<-END, __FILE__, __LINE__ + 1)}
def #{h}
super
return unless @instance_hooks
run_after_instance_hooks(:#{h})
@instance_hooks.delete(:#{h})
@instance_hooks.delete(:#{h.to_s.sub('after', 'before')})
end
END
# Run after destroy instance hooks.
def after_destroy
super
return unless @instance_hooks
run_after_instance_hooks(:after_destroy)
@instance_hooks.delete(:after_destroy)
@instance_hooks.delete(:before_destroy)
end
# Run after validation instance hooks.
def after_validation
super
return unless @instance_hooks
run_after_instance_hooks(:after_validation)
end
# Run after save instance hooks.
def after_save
super
return unless @instance_hooks
run_after_instance_hooks(:after_save)
@instance_hooks.delete(:after_save)
@instance_hooks.delete(:before_save)
@instance_hooks.delete(:after_validation)
@instance_hooks.delete(:before_validation)
end
# Run before_destroy instance hooks.
def before_destroy
return super unless @instance_hooks
run_before_instance_hooks(:before_destroy)
super
end
# Run before_save instance hooks.
def before_save
return super unless @instance_hooks
run_before_instance_hooks(:before_save)
super
end
private
# Add the block as an instance level hook. For before hooks, add it to
# the beginning of the instance hook's array. For after hooks, add it
# to the end.
def add_instance_hook(hook, &block)
instance_hooks(hook).public_send(hook.to_s.start_with?('before') ? :unshift : :push, block)
end
# An array of instance level hook blocks for the given hook type.
def instance_hooks(hook)
@instance_hooks ||= {}
@instance_hooks[hook] ||= []
end
# Run all hook blocks of the given hook type.
def run_after_instance_hooks(hook)
instance_hooks(hook).each(&:call)
end
alias run_before_instance_hooks run_after_instance_hooks
end
end
end
end
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