Mixins::

Datadir module

Adds a data_dir method and a DATA_DIR constant to extended objects. These will be set to the Pathname to the data directory distributed with a gem of the name derived from the name of the extended object. Prefers environmental override, Gem path, then local filesystem pathing.

This can also be called manually if the including class name doesn’t match the gem, or something else esoteric.

require 'mixins'

class Acme
    extend Mixins::Datadir
end

# When loading from checked-out source
Rhizos.data_dir
# => #<Pathname:../data/acme>

# With ACME_DATADIR=/path/to/data set in the environment before Ruby starts:
Rhizos.data_dir
# => #<Pathname:/path/to/data>

# When installed via gem
Rhizos.data_dir
# => #<Pathname:/path/to/lib/ruby/gems/3.4.0/gems/acme-1.0.0/data/acme>

Public Class Methods

extended( obj )

Extend hook: Set up the data_dir accessor and the DATA_DIR constant

# File lib/mixins/datadir.rb, line 38
def self::extended( obj )
        name = obj.name.downcase.gsub( '::', '-' )
        dir = self.find_datadir( name )

        obj.const_set( :DATA_DIR, dir )
        obj.singleton_class.attr_accessor :data_dir
        obj.data_dir = dir
end

find_datadir( gemname, env: nil )

Return a pathname object for the gem data directory. Use the <gemname>_DATADIR environment variable if it’s set, or the data directory of the loaded gem if there is one. If neither of those are set, fall back to a relative path of ../../data/<gemname>. You can override which environment variable is used for the override by setting env.

# File lib/mixins/datadir.rb, line 54
def self::find_datadir( gemname, env: nil )
        unless env
                comps = gemname.split( '-' )
                env = comps.size > 1 ? comps.last : comps.first
                env = "%s_DATADIR" % [ env.upcase ]
        end

        loaded_gemspec = Gem.loaded_specs[ gemname ]

        dir = if ENV[ env ]
                        Pathname( ENV[ env ] )
                elsif loaded_gemspec && File.exist?( loaded_gemspec.datadir )
                        Pathname( loaded_gemspec.datadir )
                else
                        caller_path = caller_locations( 2, 1 ).first.absolute_path
                        Pathname( caller_path ).dirname.parent.parent + "data/#{gemname}"
                end

        return dir
end