require 'active_support/core_ext/file/atomic' require 'active_support/core_ext/string/conversions' require 'uri/common' module ActiveSupport module Cache # A cache store implementation which stores everything on the filesystem. # # FileStore implements the Strategy::LocalCache strategy which implements # an in-memory cache inside of a block. class FileStore < Store attr_reader :cache_path DIR_FORMATTER = "%03X" FILENAME_MAX_SIZE = 228 # max filename size on file system is 255, minus room for timestamp and random characters appended by Tempfile (used by atomic write) EXCLUDED_DIRS = ['.', '..'].freeze def initialize(cache_path, options = nil) super(options) @cache_path = cache_path.to_s extend Strategy::LocalCache end def clear(options = nil) root_dirs = Dir.entries(cache_path).reject {|f| (EXCLUDED_DIRS + [".gitkeep"]).include?(f)} FileUtils.rm_r(root_dirs.collect{|f| File.join(cache_path, f)}) end def cleanup(options = nil) options = merged_options(options) each_key(options) do |key| entry = read_entry(key, options) delete_entry(key, options) if entry && entry.expired? end end def increment(name, amount = 1, options = nil) file_name = key_file_path(namespaced_key(name, options)) lock_file(file_name) do options = merged_options(options) if num = read(name, options) num = num.to_i + amount write(name, num, options) num else nil end end end def decrement(name, amount = 1, options = nil) file_name = key_file_path(namespaced_key(name, options)) lock_file(file_name) do options = merged_options(options) if num = read(name, options) num = num.to_i - amount write(name, num, options) num else nil end end end def delete_matched(matcher, options = nil) options = merged_options(options) instrument(:delete_matched, matcher.inspect) do matcher = key_matcher(matcher, options) search_dir(cache_path) do |path| key = file_path_key(path) delete_entry(key, options) if key.match(matcher) end end end protected def read_entry(key, options) file_name = key_file_path(key) if File.exist?(file_name) File.open(file_name) { |f| Marshal.load(f) } end rescue => e logger.error("FileStoreError (#{e}): #{e.message}") if logger nil end def write_entry(key, entry, options) file_name = key_file_path(key) ensure_cache_path(File.dirname(file_name)) File.atomic_write(file_name, cache_path) {|f| Marshal.dump(entry, f)} true end def delete_entry(key, options) file_name = key_file_path(key) if File.exist?(file_name) begin File.delete(file_name) delete_empty_directories(File.dirname(file_name)) true rescue => e # Just in case the error was caused by another process deleting the file first. raise e if File.exist?(file_name) false end end end private # Lock a file for a block so only one process can modify it at a time. def lock_file(file_name, &block) # :nodoc: if File.exist?(file_name) File.open(file_name, 'r+') do |f| begin f.flock File::LOCK_EX yield ensure f.flock File::LOCK_UN end end else yield end end # Translate a key into a file path. def key_file_path(key) fname = URI.encode_www_form_component(key) hash = Zlib.adler32(fname) hash, dir_1 = hash.divmod(0x1000) dir_2 = hash.modulo(0x1000) fname_paths = [] # Make sure file name doesn't exceed file system limits. begin fname_paths << fname[0, FILENAME_MAX_SIZE] fname = fname[FILENAME_MAX_SIZE..-1] end until fname.blank? File.join(cache_path, DIR_FORMATTER % dir_1, DIR_FORMATTER % dir_2, *fname_paths) end # Translate a file path into a key. def file_path_key(path) fname = path[cache_path.to_s.size..-1].split(File::SEPARATOR, 4).last URI.decode_www_form_component(fname, Encoding::UTF_8) end # Delete empty directories in the cache. def delete_empty_directories(dir) return if dir == cache_path if Dir.entries(dir).reject {|f| EXCLUDED_DIRS.include?(f)}.empty? File.delete(dir) rescue nil delete_empty_directories(File.dirname(dir)) end end # Make sure a file path's directories exist. def ensure_cache_path(path) FileUtils.makedirs(path) unless File.exist?(path) end def search_dir(dir, &callback) return if !File.exist?(dir) Dir.foreach(dir) do |d| next if EXCLUDED_DIRS.include?(d) name = File.join(dir, d) if File.directory?(name) search_dir(name, &callback) else callback.call name end end end end end end