vendor/rails/actionpack/lib/action_view/reloadable_template.rb

   1 module ActionView #:nodoc:
   2   class ReloadableTemplate < Template
   3
   4     class TemplateDeleted < ActionView::ActionViewError
   5     end
   6
   7     class ReloadablePath < Template::Path
   8
   9       def initialize(path)
  10         super
  11         @paths = {}
  12         new_request!
  13       end
  14
  15       def new_request!
  16         @disk_cache = {}
  17       end
  18       alias_method :load!, :new_request!
  19
  20       def [](path)
  21         if found_template = @paths[path]
  22           begin
  23             found_template.reset_cache_if_stale!
  24           rescue TemplateDeleted
  25             unregister_template(found_template)
  26             self[path]
  27           end
  28         else
  29           load_all_templates_from_dir(templates_dir_from_path(path))
  30           # don't ever hand out a template without running a stale check
  31           (new_template = @paths[path]) && new_template.reset_cache_if_stale!
  32         end
  33       end
  34
  35       private
  36         def register_template_from_file(template_full_file_path)
  37           if !@paths[relative_path = relative_path_for_template_file(template_full_file_path)] && File.file?(template_full_file_path)
  38             register_template(ReloadableTemplate.new(relative_path, self))
  39           end
  40         end
  41
  42         def register_template(template)
  43           template.accessible_paths.each do |path|
  44             @paths[path] = template
  45           end
  46         end
  47
  48         # remove (probably deleted) template from cache
  49         def unregister_template(template)
  50           template.accessible_paths.each do |template_path|
  51             @paths.delete(template_path) if @paths[template_path] == template
  52           end
  53           # fill in any newly created gaps
  54           @paths.values.uniq.each do |template|
  55             template.accessible_paths.each {|path| @paths[path] ||= template}
  56           end
  57         end
  58
  59         # load all templates from the directory of the requested template
  60         def load_all_templates_from_dir(dir)
  61           # hit disk only once per template-dir/request
  62           @disk_cache[dir] ||= template_files_from_dir(dir).each {|template_file| register_template_from_file(template_file)}
  63         end
  64
  65         def templates_dir_from_path(path)
  66           dirname = File.dirname(path)
  67           File.join(@path, dirname == '.' ? '' : dirname)
  68         end
  69
  70         # get all the template filenames from the dir
  71         def template_files_from_dir(dir)
  72           Dir.glob(File.join(dir, '*'))
  73         end
  74     end
  75
  76     module Unfreezable
  77       def freeze; self; end
  78     end
  79
  80     def initialize(*args)
  81       super
  82
  83       # we don't ever want to get frozen
  84       extend Unfreezable
  85     end
  86
  87     def mtime
  88       File.mtime(filename)
  89     end
  90
  91     attr_accessor :previously_last_modified
  92
  93     def stale?
  94       previously_last_modified.nil? || previously_last_modified < mtime
  95     rescue Errno::ENOENT => e
  96       undef_my_compiled_methods!
  97       raise TemplateDeleted
  98     end
  99
 100     def reset_cache_if_stale!
 101       if stale?
 102         flush_cache 'source', 'compiled_source'
 103         undef_my_compiled_methods!
 104         @previously_last_modified = mtime
 105       end
 106       self
 107     end
 108
 109     # remove any compiled methods that look like they might belong to me
 110     def undef_my_compiled_methods!
 111       ActionView::Base::CompiledTemplates.public_instance_methods.grep(/#{Regexp.escape(method_name_without_locals)}(?:_locals_)?/).each do |m|
 112         ActionView::Base::CompiledTemplates.send(:remove_method, m)
 113       end
 114     end
 115
 116   end
 117 end