diff options
Diffstat (limited to 'activesupport/lib/active_support/file_update_checker.rb')
-rw-r--r-- | activesupport/lib/active_support/file_update_checker.rb | 79 |
1 files changed, 72 insertions, 7 deletions
diff --git a/activesupport/lib/active_support/file_update_checker.rb b/activesupport/lib/active_support/file_update_checker.rb index 9d617b39d4..4137bbf6a0 100644 --- a/activesupport/lib/active_support/file_update_checker.rb +++ b/activesupport/lib/active_support/file_update_checker.rb @@ -1,3 +1,6 @@ +require "active_support/core_ext/array/wrap" +require "active_support/core_ext/array/extract_options" + module ActiveSupport # This class is responsible to track files and invoke the given block # whenever one of these files are changed. For example, this class @@ -15,24 +18,86 @@ module ActiveSupport class FileUpdateChecker attr_reader :paths, :last_update_at + # It accepts two parameters on initialization. The first is + # the *paths* and the second is *calculate*, a boolean. + # + # paths must be an array of file paths but can contain a hash as + # last argument. The hash must have directories as keys and the + # value is an array of extensions to be watched under that directory. + # + # If *calculate* is true, the latest updated at will calculated + # on initialization, therefore, the first call to execute_if_updated + # will only evaluate the block if something really changed. + # + # This method must also receive a block that will be the block called + # once a file changes. + # + # This particular implementation checks for added files and updated files, + # but not removed files. Directories lookup are compiled to a glob for + # performance. def initialize(paths, calculate=false, &block) @paths = paths + @glob = compile_glob(@paths.extract_options!) @block = block + @updated_at = nil @last_update_at = calculate ? updated_at : nil end - def updated_at - # TODO: Use Enumerable check once we get rid of 1.8.7 - all = paths.is_a?(Array) ? paths : Dir[paths] - all.map { |path| File.mtime(path) }.max + # Check if any of the entries were updated. If so, the updated_at + # value is cached until flush! is called. + def updated? + current_updated_at = updated_at + if @last_update_at != current_updated_at + @updated_at = updated_at + true + else + false + end + end + + # Flush the cache so updated? is calculated again + def flush! + @updated_at = nil end + # Execute the block given if updated. This call + # always flush the cache. def execute_if_updated - current_update_at = self.updated_at - if @last_update_at != current_update_at - @last_update_at = current_update_at + if updated? + @last_update_at = updated_at @block.call + true + else + false end + ensure + flush! + end + + private + + def updated_at #:nodoc: + @updated_at || begin + all = [] + all.concat @paths + all.concat Dir[@glob] if @glob + all.map { |path| File.mtime(path) }.max + end + end + + def compile_glob(hash) #:nodoc: + return if hash.empty? + globs = [] + hash.each do |key, value| + globs << "#{key}/**/*#{compile_ext(value)}" + end + "{#{globs.join(",")}}" + end + + def compile_ext(array) #:nodoc: + array = Array.wrap(array) + return if array.empty? + ".{#{array.join(",")}}" end end end |