Move actionpack/lib/action_view* into actionview/lib

1 files changed, 241 insertions, 0 deletions

diff --git a/actionview/lib/action_view/lookup_context.rb b/actionview/lib/action_view/lookup_context.rb
new file mode 100644
index 0000000000..f9d5b97fe3
--- /dev/null
+++ b/actionview/lib/action_view/lookup_context.rb
@@ -0,0 +1,241 @@
+require 'thread_safe'
+require 'active_support/core_ext/module/remove_method'
+require 'active_support/core_ext/module/attribute_accessors'
+
+module ActionView
+  # = Action View Lookup Context
+  #
+  # LookupContext is the object responsible to hold all information required to lookup
+  # templates, i.e. view paths and details. The LookupContext is also responsible to
+  # generate a key, given to view paths, used in the resolver cache lookup. Since
+  # this key is generated just once during the request, it speeds up all cache accesses.
+  class LookupContext #:nodoc:
+    attr_accessor :prefixes, :rendered_format
+
+    mattr_accessor :fallbacks
+    @@fallbacks = FallbackFileSystemResolver.instances
+
+    mattr_accessor :registered_details
+    self.registered_details = []
+
+    def self.register_detail(name, options = {}, &block)
+      self.registered_details << name
+      initialize = registered_details.map { |n| "@details[:#{n}] = details[:#{n}] || default_#{n}" }
+
+      Accessors.send :define_method, :"default_#{name}", &block
+      Accessors.module_eval <<-METHOD, __FILE__, __LINE__ + 1
+        def #{name}
+          @details.fetch(:#{name}, [])
+        end
+
+        def #{name}=(value)
+          value = value.present? ? Array(value) : default_#{name}
+          _set_detail(:#{name}, value) if value != @details[:#{name}]
+        end
+
+        remove_possible_method :initialize_details
+        def initialize_details(details)
+          #{initialize.join("\n")}
+        end
+      METHOD
+    end
+
+    # Holds accessors for the registered details.
+    module Accessors #:nodoc:
+    end
+
+    register_detail(:locale) do
+      locales = [I18n.locale]
+      locales.concat(I18n.fallbacks[I18n.locale]) if I18n.respond_to? :fallbacks
+      locales << I18n.default_locale
+      locales.uniq!
+      locales
+    end
+    register_detail(:formats) { ActionView::Base.default_formats || [:html, :text, :js, :css,  :xml, :json] }
+    register_detail(:handlers){ Template::Handlers.extensions }
+
+    class DetailsKey #:nodoc:
+      alias :eql? :equal?
+      alias :object_hash :hash
+
+      attr_reader :hash
+      @details_keys = ThreadSafe::Cache.new
+
+      def self.get(details)
+        @details_keys[details] ||= new
+      end
+
+      def self.clear
+        @details_keys.clear
+      end
+
+      def initialize
+        @hash = object_hash
+      end
+    end
+
+    # Add caching behavior on top of Details.
+    module DetailsCache
+      attr_accessor :cache
+
+      # Calculate the details key. Remove the handlers from calculation to improve performance
+      # since the user cannot modify it explicitly.
+      def details_key #:nodoc:
+        @details_key ||= DetailsKey.get(@details) if @cache
+      end
+
+      # Temporary skip passing the details_key forward.
+      def disable_cache
+        old_value, @cache = @cache, false
+        yield
+      ensure
+        @cache = old_value
+      end
+
+    protected
+
+      def _set_detail(key, value)
+        @details = @details.dup if @details_key
+        @details_key = nil
+        @details[key] = value
+      end
+    end
+
+    # Helpers related to template lookup using the lookup context information.
+    module ViewPaths
+      attr_reader :view_paths, :html_fallback_for_js
+
+      # Whenever setting view paths, makes a copy so we can manipulate then in
+      # instance objects as we wish.
+      def view_paths=(paths)
+        @view_paths = ActionView::PathSet.new(Array(paths))
+      end
+
+      def find(name, prefixes = [], partial = false, keys = [], options = {})
+        @view_paths.find(*args_for_lookup(name, prefixes, partial, keys, options))
+      end
+      alias :find_template :find
+
+      def find_all(name, prefixes = [], partial = false, keys = [], options = {})
+        @view_paths.find_all(*args_for_lookup(name, prefixes, partial, keys, options))
+      end
+
+      def exists?(name, prefixes = [], partial = false, keys = [], options = {})
+        @view_paths.exists?(*args_for_lookup(name, prefixes, partial, keys, options))
+      end
+      alias :template_exists? :exists?
+
+      # Add fallbacks to the view paths. Useful in cases you are rendering a :file.
+      def with_fallbacks
+        added_resolvers = 0
+        self.class.fallbacks.each do |resolver|
+          next if view_paths.include?(resolver)
+          view_paths.push(resolver)
+          added_resolvers += 1
+        end
+        yield
+      ensure
+        added_resolvers.times { view_paths.pop }
+      end
+
+    protected
+
+      def args_for_lookup(name, prefixes, partial, keys, details_options) #:nodoc:
+        name, prefixes = normalize_name(name, prefixes)
+        details, details_key = detail_args_for(details_options)
+        [name, prefixes, partial || false, details, details_key, keys]
+      end
+
+      # Compute details hash and key according to user options (e.g. passed from #render).
+      def detail_args_for(options)
+        return @details, details_key if options.empty? # most common path.
+        user_details = @details.merge(options)
+        [user_details, DetailsKey.get(user_details)]
+      end
+
+      # Support legacy foo.erb names even though we now ignore .erb
+      # as well as incorrectly putting part of the path in the template
+      # name instead of the prefix.
+      def normalize_name(name, prefixes) #:nodoc:
+        prefixes = prefixes.presence
+        parts    = name.to_s.split('/')
+        parts.shift if parts.first.empty?
+        name     = parts.pop
+
+        return name, prefixes || [""] if parts.empty?
+
+        parts    = parts.join('/')
+        prefixes = prefixes ? prefixes.map { |p| "#{p}/#{parts}" } : [parts]
+
+        return name, prefixes
+      end
+    end
+
+    include Accessors
+    include DetailsCache
+    include ViewPaths
+
+    def initialize(view_paths, details = {}, prefixes = [])
+      @details, @details_key = {}, nil
+      @skip_default_locale = false
+      @cache = true
+      @prefixes = prefixes
+      @rendered_format = nil
+
+      self.view_paths = view_paths
+      initialize_details(details)
+    end
+
+    # Override formats= to expand ["*/*"] values and automatically
+    # add :html as fallback to :js.
+    def formats=(values)
+      if values
+        values.concat(default_formats) if values.delete "*/*"
+        if values == [:js]
+          values << :html
+          @html_fallback_for_js = true
+        end
+      end
+      super(values)
+    end
+
+    # Do not use the default locale on template lookup.
+    def skip_default_locale!
+      @skip_default_locale = true
+      self.locale = nil
+    end
+
+    # Override locale to return a symbol instead of array.
+    def locale
+      @details[:locale].first
+    end
+
+    # Overload locale= to also set the I18n.locale. If the current I18n.config object responds
+    # to original_config, it means that it's has a copy of the original I18n configuration and it's
+    # acting as proxy, which we need to skip.
+    def locale=(value)
+      if value
+        config = I18n.config.respond_to?(:original_config) ? I18n.config.original_config : I18n.config
+        config.locale = value
+      end
+
+      super(@skip_default_locale ? I18n.locale : default_locale)
+    end
+
+    # A method which only uses the first format in the formats array for layout lookup.
+    def with_layout_format
+      if formats.size == 1
+        yield
+      else
+        old_formats = formats
+        _set_detail(:formats, formats[0,1])
+
+        begin
+          yield
+        ensure
+          _set_detail(:formats, old_formats)
+        end
+      end
+    end
+  end
+end