Centralize generator setup (#1302)

Discovered when working on #1300 

Currently we need to call `setup` in individual generation methods,
despite having already called it in `RDoc#generate`. This is because
`setup` is lazily called when we run `ri`'s server mode.

By calling `setup` eagerly in `Servlet#generator_for`, we can avoid the
repeated calls to `setup` in individual generation methods.

Right now we can NOT move `setup` into `Darkfish#initialize` yet because
`ri`'s server can[ initialize `Darkfish` with `nil`
store](https://github.com/ruby/rdoc/blob/master/lib/rdoc/servlet.rb#L335).

Author: st0012

lib/rdoc/generator/darkfish.rb

@@ -301,8 +301,6 @@ def get_sorted_module_list classes
   # Generate an index page which lists all the classes which are documented.
 
   def generate_index
-    setup
-
     template_file = @template_dir + 'index.rhtml'
     return unless template_file.exist?
 
@@ -338,8 +336,6 @@ def generate_index
   # Generates a class file for +klass+
 
   def generate_class klass, template_file = nil
-    setup
-
     current = klass
 
     template_file ||= @template_dir + 'class.rhtml'
@@ -370,8 +366,6 @@ def generate_class klass, template_file = nil
   # Generate a documentation file for each class and module
 
   def generate_class_files
-    setup
-
     template_file = @template_dir + 'class.rhtml'
     template_file = @template_dir + 'classpage.rhtml' unless
       template_file.exist?
@@ -397,8 +391,6 @@ def generate_class_files
   # Generate a documentation file for each file
 
   def generate_file_files
-    setup
-
     page_file     = @template_dir + 'page.rhtml'
     fileinfo_file = @template_dir + 'fileinfo.rhtml'
 
@@ -466,8 +458,6 @@ def generate_file_files
   # Generate a page file for +file+
 
   def generate_page file
-    setup
-
     template_file = @template_dir + 'page.rhtml'
 
     out_file = @outputdir + file.path
@@ -495,8 +485,6 @@ def generate_page file
   # Generates the 404 page for the RDoc servlet
 
   def generate_servlet_not_found message
-    setup
-
     template_file = @template_dir + 'servlet_not_found.rhtml'
     return unless template_file.exist?
 
@@ -528,8 +516,6 @@ def generate_servlet_not_found message
   # Generates the servlet root page for the RDoc servlet
 
   def generate_servlet_root installed
-    setup
-
     template_file = @template_dir + 'servlet_root.rhtml'
     return unless template_file.exist?
 
@@ -555,8 +541,6 @@ def generate_servlet_root installed
   # Generate an index page which lists all the classes which are documented.
 
   def generate_table_of_contents
-    setup
-
     template_file = @template_dir + 'table_of_contents.rhtml'
     return unless template_file.exist?
 

lib/rdoc/servlet.rb

@@ -247,6 +247,7 @@ def generator_for store
     generator = RDoc::Generator::Darkfish.new store, @options
     generator.file_output = false
     generator.asset_rel_path = '..'
+    generator.setup
 
     rdoc = RDoc::RDoc.new
     rdoc.store     = store