Class: ActiveSupport::EventedFileUpdateChecker

Inherits:
Object
  • Object
show all
Defined in:
activesupport/lib/active_support/evented_file_update_checker.rb

Overview

Allows you to “listen” to changes in a file system. The evented file updater does not hit disk when checking for updates. Instead, it uses platform-specific file system events to trigger a change in state.

The file checker takes an array of files to watch or a hash specifying directories and file extensions to watch. It also takes a block that is called when EventedFileUpdateChecker#execute is run or when EventedFileUpdateChecker#execute_if_updated is run and there have been changes to the file system.

Example:

checker = ActiveSupport::EventedFileUpdateChecker.new(["/tmp/foo"]) { puts "changed" }
checker.updated?
# => false
checker.execute_if_updated
# => nil

FileUtils.touch("/tmp/foo")

checker.updated?
# => true
checker.execute_if_updated
# => "changed"

Defined Under Namespace

Classes: Core

Instance Method Summary collapse

Constructor Details

#initialize(files, dirs = {}, &block) ⇒ EventedFileUpdateChecker

:nodoc: all


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# File 'activesupport/lib/active_support/evented_file_update_checker.rb', line 36

def initialize(files, dirs = {}, &block)
  unless block
    raise ArgumentError, "A block is required to initialize an EventedFileUpdateChecker"
  end

  @block = block
  @core = Core.new(files, dirs)
  ObjectSpace.define_finalizer(self, @core.finalizer)
end

Instance Method Details

#executeObject


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# File 'activesupport/lib/active_support/evented_file_update_checker.rb', line 55

def execute
  @core.updated.make_false
  @block.call
end

#execute_if_updatedObject


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# File 'activesupport/lib/active_support/evented_file_update_checker.rb', line 60

def execute_if_updated
  if updated?
    yield if block_given?
    execute
    true
  end
end

#updated?Boolean

Returns:

  • (Boolean)

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# File 'activesupport/lib/active_support/evented_file_update_checker.rb', line 46

def updated?
  if @core.restart?
    @core.thread_safely(&:restart)
    @core.updated.make_true
  end

  @core.updated.true?
end