require 'listen' require 'set' require 'pathname' require 'concurrent/atomic/atomic_boolean' module ActiveSupport class EventedFileUpdateChecker #:nodoc: all def initialize(files, dirs = {}, &block) @ph = PathHelper.new @files = files.map { |f| @ph.xpath(f) }.to_set @dirs = {} dirs.each do |dir, exts| @dirs[@ph.xpath(dir)] = Array(exts).map { |ext| @ph.normalize_extension(ext) } end @block = block @updated = Concurrent::AtomicBoolean.new(false) @lcsp = @ph.longest_common_subpath(@dirs.keys) if (dtw = directories_to_watch).any? Listen.to(*dtw, &method(:changed)).start end end def updated? @updated.true? end def execute @updated.make_false @block.call end def execute_if_updated if updated? execute true end end private def changed(modified, added, removed) unless updated? @updated.make_true if (modified + added + removed).any? { |f| watching?(f) } end end def watching?(file) file = @ph.xpath(file) if @files.member?(file) true elsif file.directory? false else ext = @ph.normalize_extension(file.extname) file.dirname.ascend do |dir| if @dirs.fetch(dir, []).include?(ext) break true elsif dir == @lcsp || dir.root? break false end end end end def directories_to_watch dtw = (@files + @dirs.keys).map { |f| @ph.existing_parent(f) } dtw.compact! dtw.uniq! @ph.filter_out_descendants(dtw) end class PathHelper using Module.new { refine Pathname do def ascendant_of?(other) self != other && other.ascend do |ascendant| break true if self == ascendant end end end } def xpath(path) Pathname.new(path).expand_path end def normalize_extension(ext) ext.to_s.sub(/\A\./, '') end # Given a collection of Pathname objects returns the longest subpath # common to all of them, or +nil+ if there is none. def longest_common_subpath(paths) return if paths.empty? lcsp = Pathname.new(paths[0]) paths[1..-1].each do |path| until lcsp.ascendant_of?(path) if lcsp.root? # If we get here a root directory is not an ascendant of path. # This may happen if there are paths in different drives on # Windows. return else lcsp = lcsp.parent end end end lcsp end # Returns the deepest existing ascendant, which could be the argument itself. def existing_parent(dir) dir.ascend do |ascendant| break ascendant if ascendant.directory? end end # Filters out directories which are descendants of others in the collection (stable). def filter_out_descendants(dirs) return dirs if dirs.length < 2 dirs_sorted_by_nparts = dirs.sort_by { |dir| dir.each_filename.to_a.length } descendants = [] until dirs_sorted_by_nparts.empty? dir = dirs_sorted_by_nparts.shift dirs_sorted_by_nparts.reject! do |possible_descendant| dir.ascendant_of?(possible_descendant) && descendants << possible_descendant end end # Array#- preserves order. dirs - descendants end end end end