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# frozen_string_literal: true
module Lumberjack
# The device registry is used for setting up names to represent Device classes. It is used
# in the constructor for Lumberjack::Logger and allows passing in a symbol to reference a
# device.
#
# Devices must have a constructor that accepts the options hash as its sole argument in order
# to use the device registry.
#
# The values :stdout and :stderr are registered by default and map to the standard output
# and standard error streams, respectively.
#
# @example
#
# Lumberjack::Device.register(:my_device, MyDevice)
# logger = Lumberjack::Logger.new(:my_device)
module DeviceRegistry
@registry = {stdout: :stdout, stderr: :stderr}
class << self
# Register a device name. Device names can be used to associate a symbol with a device
# class. The symbol can then be passed to Logger as the device argument.
#
# Registered devices must take only one argument and that is the options hash for the
# device options.
#
# @param name [Symbol] The name of the device
# @param klass [Class] The device class to register
# @return [void]
def add(name, klass)
raise ArgumentError.new("name must be a symbol") unless name.is_a?(Symbol)
@registry[name] = klass
end
# Remove a device from the registry.
#
# @param name [Symbol] The name of the device to remove
# @return [void]
def remove(name)
@registry.delete(name)
end
# Check if a device is registered.
#
# @param name [Symbol] The name of the device
# @return [Boolean] True if the device is registered, false otherwise
def registered?(name)
@registry.include?(name)
end
# Instantiate a new device with the specified options from the device registry.
#
# @param name [Symbol] The name of the device
# @param options [Hash] The device options
# @return [Lumberjack::Device]
def new_device(name, options)
klass = device_class(name)
unless klass
valid_names = @registry.keys.map(&:inspect).join(", ")
raise ArgumentError.new("#{name.inspect} is not registered as a device name; valid names are: #{valid_names}")
end
if klass == :stdout
Device::Writer.new($stdout, options)
elsif klass == :stderr
Device::Writer.new($stderr, options)
else
klass.new(options)
end
end
# Retrieve the class registered with the given name or nil if the name is not defined.
#
# @param name [Symbol] The name of the device
# @return [Class, nil] The registered device class or nil if not found
def device_class(name)
@registry[name]
end
# Return the map of registered device class names.
#
# @return [Hash]
def registered_devices
@registry.dup
end
end
end
end
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