Remove unused HashCaching

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@7467 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activesupport/lib/active_support/caching_tools.rb

-module ActiveSupport
-  module CachingTools #:nodoc:
-    
-    # Provide shortcuts to simply the creation of nested default hashes. This
-    # pattern is useful, common practice, and unsightly when done manually.
-    module HashCaching
-      # Dynamically create a nested hash structure used to cache calls to +method_name+
-      # The cache method is named +#{method_name}_cache+ unless :as => :alternate_name
-      # is given.
-      #
-      # The hash structure is created using nested Hash.new. For example:
-      # 
-      #   def slow_method(a, b) a ** b end
-      # 
-      # can be cached using hash_cache :slow_method, which will define the method
-      # slow_method_cache. We can then find the result of a ** b using:
-      # 
-      #   slow_method_cache[a][b]
-      # 
-      # The hash structure returned by slow_method_cache would look like this:
-      # 
-      #   Hash.new do |as, a|
-      #     as[a] = Hash.new do |bs, b|
-      #       bs[b] = slow_method(a, b)
-      #     end
-      #   end
-      # 
-      # The generated code is actually compressed onto a single line to maintain
-      # sensible backtrace signatures.
-      #
-      def hash_cache(method_name, options = {})
-        selector = options[:as] || "#{method_name}_cache"
-        method = self.instance_method(method_name)
-        
-        args = []
-        code = "def #{selector}(); @#{selector} ||= "
-        
-        (1..method.arity).each do |n|
-          args << "v#{n}"
-          code << "Hash.new {|h#{n}, v#{n}| h#{n}[v#{n}] = "
-        end
-        
-        # Add the method call with arguments, followed by closing braces and end.
-        code << "#{method_name}(#{args * ', '}) #{'}' * method.arity} end"
-        
-        # Extract the line number information from the caller. Exceptions arising
-        # in the generated code should point to the +hash_cache :...+ line.
-        if caller[0] && /^(.*):(\d+)$/ =~ caller[0]
-          file, line_number = $1, $2.to_i
-        else # We can't give good trackback info; fallback to this line:
-          file, line_number = __FILE__, __LINE__
-        end
-        
-        # We use eval rather than building proc's because it allows us to avoid
-        # linking the Hash's to this method's binding. Experience has shown that
-        # doing so can cause obtuse memory leaks.
-        class_eval code, file, line_number
-      end
-    end
-    
-  end
-end

activesupport/test/caching_tools_test.rb

-require File.dirname(__FILE__) + '/abstract_unit'
-require File.join(File.dirname(File.dirname(__FILE__)), 'lib/active_support/caching_tools.rb')
-
-class HashCachingTests < Test::Unit::TestCase
-  def cached(&proc)
-    return @cached if defined?(@cached)
-
-    @cached_class = Class.new(&proc)
-    @cached_class.class_eval do
-      extend ActiveSupport::CachingTools::HashCaching
-      hash_cache :slow_method
-    end
-    @cached = @cached_class.new
-  end
-
-  def test_cache_access_should_call_method
-    cached do
-      def slow_method(a) raise "I should be here: #{a}"; end
-    end
-    assert_raises(RuntimeError) { cached.slow_method_cache[1] }
-  end
-
-  def test_cache_access_should_actually_cache
-    cached do
-      def slow_method(a)
-        (@x ||= [])
-        if @x.include?(a) then raise "Called twice for #{a}!"
-        else
-          @x << a
-          a + 1
-        end
-      end
-    end
-    assert_equal 11, cached.slow_method_cache[10]
-    assert_equal 12, cached.slow_method_cache[11]
-    assert_equal 11, cached.slow_method_cache[10]
-    assert_equal 12, cached.slow_method_cache[11]
-  end
-
-  def test_cache_should_be_clearable
-    cached do
-      def slow_method(a)
-        @x ||= 0
-        @x += 1
-      end
-    end
-    assert_equal 1, cached.slow_method_cache[:a]
-    assert_equal 2, cached.slow_method_cache[:b]
-    assert_equal 3, cached.slow_method_cache[:c]
-
-    assert_equal 1, cached.slow_method_cache[:a]
-    assert_equal 2, cached.slow_method_cache[:b]
-    assert_equal 3, cached.slow_method_cache[:c]
-
-    cached.slow_method_cache.clear
-
-    assert_equal 4, cached.slow_method_cache[:a]
-    assert_equal 5, cached.slow_method_cache[:b]
-    assert_equal 6, cached.slow_method_cache[:c]
-  end
-
-  def test_deep_caches_should_work_too
-    cached do
-      def slow_method(a, b, c)
-        a + b + c
-      end
-    end
-    assert_equal 3, cached.slow_method_cache[1][1][1]
-    assert_equal 7, cached.slow_method_cache[1][2][4]
-    assert_equal 7, cached.slow_method_cache[1][2][4]
-    assert_equal 7, cached.slow_method_cache[4][2][1]
-
-    assert_equal({
-      1 => {1 => {1 => 3}, 2 => {4 => 7}},
-      4 => {2 => {1 => 7}}},
-      cached.slow_method_cache
-    )
-  end
-end