aboutsummaryrefslogtreecommitdiffstats
path: root/actionview/lib/action_view/lookup_context.rb
blob: 8b7ede250a2b9af420f804549cf608c59ef8fef9 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
require 'concurrent'
require 'active_support/core_ext/module/remove_method'
require 'active_support/core_ext/module/attribute_accessors'
require 'action_view/template/resolver'

module ActionView
  # = Action View Lookup Context
  #
  # <tt>LookupContext</tt> is the object responsible for holding all information
  # required for looking up templates, i.e. view paths and details.
  # <tt>LookupContext</tt> is also responsible for generating a key, given to
  # view paths, used in the resolver cache lookup. Since this key is generated
  # only 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(:variants) { [] }
    register_detail(:handlers){ Template::Handlers.extensions }

    class DetailsKey #:nodoc:
      alias :eql? :equal?
      alias :object_hash :hash

      attr_reader :hash
      @details_keys = Concurrent::Map.new

      def self.get(details)
        if details[:formats]
          details = details.dup
          details[:formats] &= Mime::SET.symbols
        end
        @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 that we can manipulate them 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?

      # Adds fallbacks to the view paths. Useful in cases when 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)

        if @cache
          details_key = DetailsKey.get(user_details)
        else
          details_key = nil
        end

        [user_details, details_key]
      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('/'.freeze)
        parts.shift if parts.first.empty?
        name     = parts.pop

        return name, prefixes || [""] if parts.empty?

        parts    = parts.join('/'.freeze)
        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
      @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 "*/*".freeze
        if values == [:js]
          values << :html
          @html_fallback_for_js = true
        end
      end
      super(values)
    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 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(default_locale)
    end
  end
end