aboutsummaryrefslogtreecommitdiffstats
path: root/actionview/lib/action_view/template/resolver.rb
blob: b65507f4a20807dccbec970b865bca17e7b07401 (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
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
require "pathname"
require "active_support/core_ext/class"
require "active_support/core_ext/module/attribute_accessors"
require 'active_support/core_ext/string/filters'
require "action_view/template"
require "thread"
require "thread_safe"

module ActionView
  # = Action View Resolver
  class Resolver
    # Keeps all information about view path and builds virtual path.
    class Path
      attr_reader :name, :prefix, :partial, :virtual
      alias_method :partial?, :partial

      def self.build(name, prefix, partial)
        virtual = ""
        virtual << "#{prefix}/" unless prefix.empty?
        virtual << (partial ? "_#{name}" : name)
        new name, prefix, partial, virtual
      end

      def initialize(name, prefix, partial, virtual)
        @name    = name
        @prefix  = prefix
        @partial = partial
        @virtual = virtual
      end

      def to_str
        @virtual
      end
      alias :to_s :to_str
    end

    # Threadsafe template cache
    class Cache #:nodoc:
      class SmallCache < ThreadSafe::Cache
        def initialize(options = {})
          super(options.merge(:initial_capacity => 2))
        end
      end

      # preallocate all the default blocks for performance/memory consumption reasons
      PARTIAL_BLOCK = lambda {|cache, partial| cache[partial] = SmallCache.new}
      PREFIX_BLOCK  = lambda {|cache, prefix|  cache[prefix]  = SmallCache.new(&PARTIAL_BLOCK)}
      NAME_BLOCK    = lambda {|cache, name|    cache[name]    = SmallCache.new(&PREFIX_BLOCK)}
      KEY_BLOCK     = lambda {|cache, key|     cache[key]     = SmallCache.new(&NAME_BLOCK)}

      # usually a majority of template look ups return nothing, use this canonical preallocated array to save memory
      NO_TEMPLATES = [].freeze

      def initialize
        @data = SmallCache.new(&KEY_BLOCK)
      end

      # Cache the templates returned by the block
      def cache(key, name, prefix, partial, locals)
        if Resolver.caching?
          @data[key][name][prefix][partial][locals] ||= canonical_no_templates(yield)
        else
          fresh_templates  = yield
          cached_templates = @data[key][name][prefix][partial][locals]

          if templates_have_changed?(cached_templates, fresh_templates)
            @data[key][name][prefix][partial][locals] = canonical_no_templates(fresh_templates)
          else
            cached_templates || NO_TEMPLATES
          end
        end
      end

      def clear
        @data.clear
      end

      private

      def canonical_no_templates(templates)
        templates.empty? ? NO_TEMPLATES : templates
      end

      def templates_have_changed?(cached_templates, fresh_templates)
        # if either the old or new template list is empty, we don't need to (and can't)
        # compare modification times, and instead just check whether the lists are different
        if cached_templates.blank? || fresh_templates.blank?
          return fresh_templates.blank? != cached_templates.blank?
        end

        cached_templates_max_updated_at = cached_templates.map(&:updated_at).max

        # if a template has changed, it will be now be newer than all the cached templates
        fresh_templates.any? { |t| t.updated_at > cached_templates_max_updated_at }
      end
    end

    cattr_accessor :caching
    self.caching = true

    class << self
      alias :caching? :caching
    end

    def initialize
      @cache = Cache.new
    end

    def clear_cache
      @cache.clear
    end

    # Normalizes the arguments and passes it on to find_templates.
    def find_all(name, prefix=nil, partial=false, details={}, key=nil, locals=[])
      cached(key, [name, prefix, partial], details, locals) do
        find_templates(name, prefix, partial, details)
      end
    end

  private

    delegate :caching?, to: :class

    # This is what child classes implement. No defaults are needed
    # because Resolver guarantees that the arguments are present and
    # normalized.
    def find_templates(name, prefix, partial, details)
      raise NotImplementedError, "Subclasses must implement a find_templates(name, prefix, partial, details) method"
    end

    # Helpers that builds a path. Useful for building virtual paths.
    def build_path(name, prefix, partial)
      Path.build(name, prefix, partial)
    end

    # Handles templates caching. If a key is given and caching is on
    # always check the cache before hitting the resolver. Otherwise,
    # it always hits the resolver but if the key is present, check if the
    # resolver is fresher before returning it.
    def cached(key, path_info, details, locals) #:nodoc:
      name, prefix, partial = path_info
      locals = locals.map { |x| x.to_s }.sort!

      if key
        @cache.cache(key, name, prefix, partial, locals) do
          decorate(yield, path_info, details, locals)
        end
      else
        decorate(yield, path_info, details, locals)
      end
    end

    # Ensures all the resolver information is set in the template.
    def decorate(templates, path_info, details, locals) #:nodoc:
      cached = nil
      templates.each do |t|
        t.locals         = locals
        t.formats        = details[:formats]  || [:html] if t.formats.empty?
        t.variants       = details[:variants] || []      if t.variants.empty?
        t.virtual_path ||= (cached ||= build_path(*path_info))
      end
    end
  end

  # An abstract class that implements a Resolver with path semantics.
  class PathResolver < Resolver #:nodoc:
    EXTENSIONS = { :locale => ".", :formats => ".", :variants => "+", :handlers => "." }
    DEFAULT_PATTERN = ":prefix/:action{.:locale,}{.:formats,}{+:variants,}{.:handlers,}"

    def initialize(pattern=nil)
      @pattern = pattern || DEFAULT_PATTERN
      super()
    end

    private

    def find_templates(name, prefix, partial, details)
      path = Path.build(name, prefix, partial)
      query(path, details, details[:formats])
    end

    def query(path, details, formats)
      query = build_query(path, details)

      template_paths = find_template_paths query

      template_paths.map { |template|
        handler, format, variant = extract_handler_and_format_and_variant(template, formats)
        contents = File.binread(template)

        Template.new(contents, File.expand_path(template), handler,
          :virtual_path => path.virtual,
          :format       => format,
          :variant      => variant,
          :updated_at   => mtime(template)
        )
      }
    end

    if RUBY_VERSION >= '2.2.0'
      def find_template_paths(query)
        Dir[query].reject { |filename|
          File.directory?(filename) ||
            # deals with case-insensitive file systems.
            !File.fnmatch(query, filename, File::FNM_EXTGLOB)
        }
      end
    else
      def find_template_paths(query)
        # deals with case-insensitive file systems.
        sanitizer = Hash.new { |h,dir| h[dir] = Dir["#{dir}/*"] }

        Dir[query].reject { |filename|
          File.directory?(filename) ||
            !sanitizer[File.dirname(filename)].include?(filename)
        }
      end
    end

    # Helper for building query glob string based on resolver's pattern.
    def build_query(path, details)
      query = @pattern.dup

      prefix = path.prefix.empty? ? "" : "#{escape_entry(path.prefix)}\\1"
      query.gsub!(/\:prefix(\/)?/, prefix)

      partial = escape_entry(path.partial? ? "_#{path.name}" : path.name)
      query.gsub!(/\:action/, partial)

      details.each do |ext, variants|
        query.gsub!(/\:#{ext}/, "{#{variants.compact.uniq.join(',')}}")
      end

      File.expand_path(query, @path)
    end

    def escape_entry(entry)
      entry.gsub(/[*?{}\[\]]/, '\\\\\\&')
    end

    # Returns the file mtime from the filesystem.
    def mtime(p)
      File.mtime(p)
    end

    # Extract handler, formats and variant from path. If a format cannot be found neither
    # from the path, or the handler, we should return the array of formats given
    # to the resolver.
    def extract_handler_and_format_and_variant(path, default_formats)
      pieces = File.basename(path).split(".")
      pieces.shift

      extension = pieces.pop
      unless extension
        ActiveSupport::Deprecation.warn(<<-MSG.squish)
          The file #{path} did not specify a template handler. The default is
          currently ERB, but will change to RAW in the future.
        MSG
      end

      handler = Template.handler_for_extension(extension)
      format, variant = pieces.last.split(EXTENSIONS[:variants], 2) if pieces.last
      format  &&= Template::Types[format]

      [handler, format, variant]
    end
  end

  # A resolver that loads files from the filesystem. It allows setting your own
  # resolving pattern. Such pattern can be a glob string supported by some variables.
  #
  # ==== Examples
  #
  # Default pattern, loads views the same way as previous versions of rails, eg. when you're
  # looking for `users/new` it will produce query glob: `users/new{.{en},}{.{html,js},}{.{erb,haml},}`
  #
  #   FileSystemResolver.new("/path/to/views", ":prefix/:action{.:locale,}{.:formats,}{+:variants,}{.:handlers,}")
  #
  # This one allows you to keep files with different formats in separate subdirectories,
  # eg. `users/new.html` will be loaded from `users/html/new.erb` or `users/new.html.erb`,
  # `users/new.js` from `users/js/new.erb` or `users/new.js.erb`, etc.
  #
  #   FileSystemResolver.new("/path/to/views", ":prefix/{:formats/,}:action{.:locale,}{.:formats,}{+:variants,}{.:handlers,}")
  #
  # If you don't specify a pattern then the default will be used.
  #
  # In order to use any of the customized resolvers above in a Rails application, you just need
  # to configure ActionController::Base.view_paths in an initializer, for example:
  #
  #   ActionController::Base.view_paths = FileSystemResolver.new(
  #     Rails.root.join("app/views"),
  #     ":prefix{/:locale}/:action{.:formats,}{+:variants,}{.:handlers,}"
  #   )
  #
  # ==== Pattern format and variables
  #
  # Pattern has to be a valid glob string, and it allows you to use the
  # following variables:
  #
  # * <tt>:prefix</tt> - usually the controller path
  # * <tt>:action</tt> - name of the action
  # * <tt>:locale</tt> - possible locale versions
  # * <tt>:formats</tt> - possible request formats (for example html, json, xml...)
  # * <tt>:variants</tt> - possible request variants (for example phone, tablet...)
  # * <tt>:handlers</tt> - possible handlers (for example erb, haml, builder...)
  #
  class FileSystemResolver < PathResolver
    def initialize(path, pattern=nil)
      raise ArgumentError, "path already is a Resolver class" if path.is_a?(Resolver)
      super(pattern)
      @path = File.expand_path(path)
    end

    def to_s
      @path.to_s
    end
    alias :to_path :to_s

    def eql?(resolver)
      self.class.equal?(resolver.class) && to_path == resolver.to_path
    end
    alias :== :eql?
  end

  # An Optimized resolver for Rails' most common case.
  class OptimizedFileSystemResolver < FileSystemResolver #:nodoc:
    def build_query(path, details)
      query = escape_entry(File.join(@path, path))

      exts = EXTENSIONS.map do |ext, prefix|
        "{#{details[ext].compact.uniq.map { |e| "#{prefix}#{e}," }.join}}"
      end.join

      query + exts
    end
  end

  # The same as FileSystemResolver but does not allow templates to store
  # a virtual path since it is invalid for such resolvers.
  class FallbackFileSystemResolver < FileSystemResolver #:nodoc:
    def self.instances
      [new(""), new("/")]
    end

    def decorate(*)
      super.each { |t| t.virtual_path = nil }
    end
  end
end