# frozen_string_literal: true
require "active_support/core_ext/file/atomic"
require "active_support/core_ext/string/conversions"
require "uri/common"
module ActiveSupport
module Cache
# = \File \Cache \Store
#
# A cache store implementation which stores everything on the filesystem.
class FileStore < Store
attr_reader :cache_path
DIR_FORMATTER = "%03X"
FILENAME_MAX_SIZE = 226 # max filename size on file system is 255, minus room for timestamp, pid, and random characters appended by Tempfile (used by atomic write)
FILEPATH_MAX_SIZE = 900 # max is 1024, plus some room
GITKEEP_FILES = [".gitkeep", ".keep"].freeze
def initialize(cache_path, **options)
super(options)
@cache_path = cache_path.to_s
end
# Advertise cache versioning support.
def self.supports_cache_versioning?
true
end
# Deletes all items from the cache. In this case it deletes all the entries in the specified
# file store directory except for .keep or .gitkeep. Be careful which directory is specified in your
# config file when using +FileStore+ because everything in that directory will be deleted.
def clear(options = nil)
root_dirs = (Dir.children(cache_path) - GITKEEP_FILES)
FileUtils.rm_r(root_dirs.collect { |f| File.join(cache_path, f) })
rescue Errno::ENOENT, Errno::ENOTEMPTY
end
# Preemptively iterates through all stored keys and removes the ones which have expired.
def cleanup(options = nil)
options = merged_options(options)
search_dir(cache_path) do |fname|
entry = read_entry(fname, **options)
delete_entry(fname, **options) if entry && entry.expired?
end
end
# Increment a cached integer value. Returns the updated value.
#
# If the key is unset, it starts from +0+:
#
# cache.increment("foo") # => 1
# cache.increment("bar", 100) # => 100
#
# To set a specific value, call #write:
#
# cache.write("baz", 5)
# cache.increment("baz") # => 6
#
def increment(name, amount = 1, options = nil)
modify_value(name, amount, options)
end
# Decrement a cached integer value. Returns the updated value.
#
# If the key is unset, it will be set to +-amount+.
#
# cache.decrement("foo") # => -1
#
# To set a specific value, call #write:
#
# cache.write("baz", 5)
# cache.decrement("baz") # => 4
#
def decrement(name, amount = 1, options = nil)
modify_value(name, -amount, options)
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(path, **options) if key.match(matcher)
end
end
end
def inspect # :nodoc:
"#<#{self.class.name} cache_path=#{@cache_path}, options=#{@options.inspect}>"
end
private
def read_entry(key, **options)
if payload = read_serialized_entry(key, **options)
entry = deserialize_entry(payload)
entry if entry.is_a?(Cache::Entry)
end
end
def read_serialized_entry(key, **)
File.binread(key) if File.exist?(key)
rescue => error
logger.error("FileStoreError (#{error}): #{error.message}") if logger
nil
end
def write_entry(key, entry, **options)
write_serialized_entry(key, serialize_entry(entry, **options), **options)
end
def write_serialized_entry(key, payload, **options)
return false if options[:unless_exist] && File.exist?(key)
ensure_cache_path(File.dirname(key))
File.atomic_write(key, cache_path) { |f| f.write(payload) }
true
end
def delete_entry(key, **options)
if File.exist?(key)
begin
File.delete(key)
delete_empty_directories(File.dirname(key))
true
rescue
# Just in case the error was caused by another process deleting the file first.
raise if File.exist?(key)
false
end
else
false
end
end
# Lock a file for a block so only one process can modify it at a time.
def lock_file(file_name, &block)
if File.exist?(file_name)
File.open(file_name, "r+") do |f|
f.flock File::LOCK_EX
yield
ensure
f.flock File::LOCK_UN
end
else
yield
end
end
# Translate a key into a file path.
def normalize_key(key, options)
key = super
fname = URI.encode_www_form_component(key)
if fname.size > FILEPATH_MAX_SIZE
fname = ActiveSupport::Digest.hexdigest(key)
end
hash = Zlib.adler32(fname)
hash, dir_1 = hash.divmod(0x1000)
dir_2 = hash.modulo(0x1000)
# Make sure file name doesn't exceed file system limits.
if fname.length < FILENAME_MAX_SIZE
fname_paths = fname
else
fname_paths = []
begin
fname_paths << fname[0, FILENAME_MAX_SIZE]
fname = fname[FILENAME_MAX_SIZE..-1]
end until fname.blank?
end
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.delete(File::SEPARATOR)
URI.decode_www_form_component(fname, Encoding::UTF_8)
end
# Delete empty directories in the cache.
def delete_empty_directories(dir)
return if File.realpath(dir) == File.realpath(cache_path)
if Dir.children(dir).empty?
Dir.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.each_child(dir) do |d|
name = File.join(dir, d)
if File.directory?(name)
search_dir(name, &callback)
else
callback.call name
end
end
end
# Modifies the amount of an integer value that is stored in the cache.
# If the key is not found it is created and set to +amount+.
def modify_value(name, amount, options)
file_name = normalize_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
write(name, Integer(amount), options)
amount
end
end
end
end
end
end