class ActionView::Digestor - actionview-4.2.3 Documentation

# class ActionView::Digestor

### Attributes

finder[R]
name[R]
options[R]

### Public Class Methods

digest(options) click to toggle source

Supported options:

- `name` - Template name

- `finder` - An instance of ActionView::LookupContext

- `dependencies` - An array of dependent views

- `partial` - Specifies whether the template is a partial

    # File lib/action_view/digestor.rb, line 18
    def digest(options)
      options.assert_valid_keys(:name, :finder, :dependencies, :partial)

      cache_key = ([ options[:name], options[:finder].details_key.hash ].compact + Array.wrap(options[:dependencies])).join('.')

      # this is a correctly done double-checked locking idiom
      # (ThreadSafe::Cache's lookups have volatile semantics)
      @@cache[cache_key] || @@digest_monitor.synchronize do
        @@cache.fetch(cache_key) do # re-check under lock
          compute_and_store_digest(cache_key, options)
        end
      end
    end

new(options) click to toggle source

    # File lib/action_view/digestor.rb, line 56
    def initialize(options)
      @name, @finder = options.values_at(:name, :finder)
      @options = options.except(:name, :finder)
    end

### Private Class Methods

compute_and_store_digest(cache_key, options) click to toggle source

    # File lib/action_view/digestor.rb, line 33
    def compute_and_store_digest(cache_key, options) # called under @@digest_monitor lock
      klass = if options[:partial] || options[:name].include?("/_")
        # Prevent re-entry or else recursive templates will blow the stack.
        # There is no need to worry about other threads seeing the +false+ value,
        # as they will then have to wait for this thread to let go of the @@digest_monitor lock.
        pre_stored = @@cache.put_if_absent(cache_key, false).nil? # put_if_absent returns nil on insertion
        PartialDigestor
      else
        Digestor
      end

      digest = klass.new(options).digest
      # Store the actual digest if config.cache_template_loading is true
      @@cache[cache_key] = stored_digest = digest if ActionView::Resolver.caching?
      digest
    ensure
      # something went wrong or ActionView::Resolver.caching? is false, make sure not to corrupt the @@cache
      @@cache.delete_pair(cache_key, false) if pre_stored && !stored_digest
    end

### Public Instance Methods

dependencies() click to toggle source

    # File lib/action_view/digestor.rb, line 70
    def dependencies
      DependencyTracker.find_dependencies(name, template)
    rescue ActionView::MissingTemplate
      logger.try :error, "  '#{name}' file doesn't exist, so no dependencies"
      []
    end

digest() click to toggle source

    # File lib/action_view/digestor.rb, line 61
    def digest
      Digest::MD5.hexdigest("#{source}-#{dependency_digest}").tap do |digest|
        logger.try :debug, "  Cache digest for #{template.inspect}: #{digest}"
      end
    rescue ActionView::MissingTemplate
      logger.try :error, "  Couldn't find template for digesting: #{name}"
      ''
    end

nested_dependencies() click to toggle source

    # File lib/action_view/digestor.rb, line 77
    def nested_dependencies
      dependencies.collect do |dependency|
        dependencies = PartialDigestor.new(name: dependency, finder: finder).nested_dependencies
        dependencies.any? ? { dependency => dependencies } : dependency
      end
    end

### Private Instance Methods

dependency_digest() click to toggle source

    # File lib/action_view/digestor.rb, line 105
    def dependency_digest
      template_digests = dependencies.collect do |template_name|
        Digestor.digest(name: template_name, finder: finder, partial: true)
      end

      (template_digests + injected_dependencies).join("-")
    end

injected_dependencies() click to toggle source

    # File lib/action_view/digestor.rb, line 113
    def injected_dependencies
      Array.wrap(options[:dependencies])
    end

logger() click to toggle source

    # File lib/action_view/digestor.rb, line 85
    def logger
      ActionView::Base.logger
    end

logical_name() click to toggle source

    # File lib/action_view/digestor.rb, line 89
    def logical_name
      name.gsub(%r|/_|, "/")
    end

partial?() click to toggle source

    # File lib/action_view/digestor.rb, line 93
    def partial?
      false
    end

source() click to toggle source

    # File lib/action_view/digestor.rb, line 101
    def source
      template.source
    end

template() click to toggle source

    # File lib/action_view/digestor.rb, line 97
    def template
      @template ||= finder.disable_cache { finder.find(logical_name, [], partial?) }
    end