Initial commit

Author: Saimon Moore

History.txt

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+=== 0.9.8 / 2008-12-07
+
+* Initial commit

LICENSE

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+Copyright (c) 2008 Saimon Moore
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Manifest.txt

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+History.txt
+LICENSE
+Manifest.txt
+README.txt
+Rakefile
+TODO
+lib/dm-counter-cache.rb
+lib/dm-counter-cache/version.rb
+spec/integration/dm-counter-cache_spec.rb
+spec/spec.opts
+spec/spec_helper.rb
+tasks/install.rb
+tasks/spec.rb

README.txt

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+== README
+
+DataMapper::CounterCacheable automates the dec/incrementing of association counter fields. This is
+similar to counter caches in ActiveRecord.
+
+Example:
+
+class Post
+  include DataMapper::Resource
+
+  has n :comments
+
+  property :id, Integer, :serial => true
+  property :comments_count, Integer, :default => 0
+end
+
+class Comment
+  include DataMapper::Resource
+  include DataMapper::CounterCacheable  
+
+  belongs_to :post, :counter_cache => true
+
+end

Rakefile

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+require 'pathname'
+require 'rubygems'
+
+ROOT    = Pathname(__FILE__).dirname.expand_path
+JRUBY   = RUBY_PLATFORM =~ /java/
+WINDOWS = Gem.win_platform?
+SUDO    = (WINDOWS || JRUBY) ? '' : ('sudo' unless ENV['SUDOLESS'])
+
+require ROOT + 'lib/dm-counter-cache/version'
+
+AUTHOR = 'Saimon Moore'
+EMAIL  = 'saimonmoore [a] gmail [d] com'
+GEM_NAME = 'dm-counter-cache'
+GEM_VERSION = DataMapper::CounterCacheable::VERSION
+GEM_DEPENDENCIES = [['dm-core', "~>#{GEM_VERSION}"]]
+GEM_CLEAN = %w[ log pkg coverage ]
+GEM_EXTRAS = { :has_rdoc => true, :extra_rdoc_files => %w[ README.txt LICENSE TODO History.txt ] }
+
+PROJECT_NAME = 'datamapper'
+PROJECT_URL  = "http://github.com/saimonmoore/dm-counter-cache/tree/master/#{GEM_NAME}"
+PROJECT_DESCRIPTION = PROJECT_SUMMARY = 'DataMapper plugin for for counter caches ala ActiveRecord'
+
+[ ROOT, ROOT.parent ].each do |dir|
+  Pathname.glob(dir.join('tasks/**/*.rb').to_s).each { |f| require f }
+end

TODO

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+module DataMapper
+  # CounterCacheable allows you to transparently maintain counts on collection association of this model on the parent model.
+  # You can also specify a custom counter cache column by providing a column name instead of a true/false value 
+  # to this option (e.g., :counter_cache => :my_custom_counter.)
+  module CounterCacheable
+
+    def self.included(klass)      
+      DataMapper::Associations::ManyToOne.module_eval {
+        extend DataMapper::CounterCacheable::ClassMethods
+        (class << self; self; end).class_eval do
+          alias_method :setup_without_counter_caching, :setup
+          alias_method :setup, :setup_with_counter_caching
+        end
+      }
+    end
+
+    module ClassMethods
+      
+      def setup_with_counter_caching(name, model, options = {})
+        counter_cache_attribute = options.delete(:counter_cache)
+        relationship = setup_without_counter_caching(name, model, options)
+        
+        if counter_cache_attribute
+          case counter_cache_attribute
+            when String, Symbol
+              counter_cache_attribute = counter_cache_attribute.intern
+            else
+              counter_cache_attribute = "#{model.storage_name}_count".intern
+          end
+
+          relationship.parent_model.class_eval <<-EOS, __FILE__, __LINE__
+            property :#{counter_cache_attribute}, Integer, :default => 0, :lazy => false          
+          EOS
+          
+          parent_name = relationship.parent_model.name.downcase
+
+          model.class_eval <<-EOS, __FILE__, __LINE__            
+            after :create, :increment_counter_cache_for_#{parent_name}
+            after :destroy, :decrement_counter_cache_for_#{parent_name}
+          
+            def increment_counter_cache_for_#{parent_name}
+              self.#{parent_name}.update_attributes(:#{counter_cache_attribute} => self.#{parent_name}.#{counter_cache_attribute}.succ)
+            end
+
+            def decrement_counter_cache_for_#{parent_name}
+              self.#{parent_name}.update_attributes(:#{counter_cache_attribute} => self.#{parent_name}.#{counter_cache_attribute} - 1)
+            end
+            
+          EOS
+        end
+
+        relationship
+      end
+
+    end # ClassMethods
+
+  end # CounterCacheable
+end # DataMapper
+
+if $0 == __FILE__
+  require 'rubygems'
+
+  gem 'dm-core', '~>0.9.8'
+  require 'dm-core'
+
+  FileUtils.touch(File.join(Dir.pwd, "migration_test.db"))
+  DataMapper.setup(:default, "sqlite3://#{Dir.pwd}/migration_test.db")
+
+  class Post
+    include DataMapper::Resource
+
+    property :id, Integer, :serial => true
+    has n, :comments
+  end
+  Post.auto_migrate!
+  
+  class Comment
+    include DataMapper::Resource
+    include DataMapper::CounterCacheable
+
+    belongs_to :post, :counter_cache => true
+  end
+  Comments.auto_migrate!
+
+  Post.create.comments.create
+end

lib/dm-counter-cache.rb

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+module DataMapper
+  module CounterCacheable
+    VERSION = '0.9.8'
+  end
+end

lib/dm-counter-cache/version.rb

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+require 'pathname'
+require Pathname(__FILE__).dirname.expand_path.parent + 'spec_helper'
+
+describe DataMapper::CounterCacheable do
+  before :all do
+    class Post
+      include DataMapper::Resource
+
+      has n, :comments
+
+      property :id, Integer, :serial => true
+      property :comments_count, Integer, :default => 0
+    end
+    
+    class Comment
+      include DataMapper::Resource
+      include DataMapper::CounterCacheable  
+
+      property :id, Integer, :serial => true
+      belongs_to :post, :counter_cache => true
+
+    end
+    
+    Comment.auto_migrate!
+    Post.auto_migrate!
+  end
+
+  before(:each) do
+    @post = Post.create
+  end
+
+  it "should increment comments_count" do
+    @post.comments.create
+    @post.reload.comments_count.should == 1
+  end
+
+  it "should decrement comments_count" do
+    comment1 = @post.comments.create    
+    comment2 = @post.comments.create
+    comment2.destroy
+    @post.reload.comments_count.should == 1
+  end
+
+end

spec/integration/dm-counter-cache_spec.rb

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+--colour

spec/spec.opts

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+require 'pathname'
+require 'rubygems'
+
+gem 'rspec', '~>1.1.11'
+require 'spec'
+
+gem 'dm-core', '~>0.9.8'
+require 'dm-core'
+
+require Pathname(__FILE__).dirname.parent.expand_path + 'lib/dm-counter-cache'
+
+def load_driver(name, default_uri)
+  return false if ENV['ADAPTER'] != name.to_s
+
+  begin
+    DataMapper.setup(name, ENV["#{name.to_s.upcase}_SPEC_URI"] || default_uri)
+    DataMapper::Repository.adapters[:default] =  DataMapper::Repository.adapters[name]
+    true
+  rescue LoadError => e
+    warn "Could not load do_#{name}: #{e}"
+    false
+  end
+end
+
+ENV['ADAPTER'] ||= 'sqlite3'
+
+HAS_SQLITE3  = load_driver(:sqlite3,  'sqlite3::memory:')
+HAS_MYSQL    = load_driver(:mysql,    'mysql://localhost/dm_core_test')
+HAS_POSTGRES = load_driver(:postgres, 'postgres://postgres@localhost/dm_core_test')

spec/spec_helper.rb

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+def sudo_gem(cmd)
+  sh "#{SUDO} #{RUBY} -S gem #{cmd}", :verbose => false
+end
+
+desc "Install #{GEM_NAME} #{GEM_VERSION}"
+task :install => [ :package ] do
+  sudo_gem "install --local pkg/#{GEM_NAME}-#{GEM_VERSION} --no-update-sources"
+end
+
+desc "Uninstall #{GEM_NAME} #{GEM_VERSION}"
+task :uninstall => [ :clobber ] do
+  sudo_gem "uninstall #{GEM_NAME} -v#{GEM_VERSION} -Ix"
+end

tasks/install.rb

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+begin
+  gem 'rspec', '~>1.1.11'
+  require 'spec'
+  require 'spec/rake/spectask'
+
+  task :default => [ :spec ]
+
+  desc 'Run specifications'
+  Spec::Rake::SpecTask.new(:spec) do |t|
+    t.spec_opts << '--options' << 'spec/spec.opts' if File.exists?('spec/spec.opts')
+    t.spec_files = Pathname.glob((ROOT + 'spec/**/*_spec.rb').to_s)
+
+    begin
+      gem 'rcov', '~>0.8'
+      t.rcov = JRUBY ? false : (ENV.has_key?('NO_RCOV') ? ENV['NO_RCOV'] != 'true' : true)
+      t.rcov_opts << '--exclude' << 'spec'
+      t.rcov_opts << '--text-summary'
+      t.rcov_opts << '--sort' << 'coverage' << '--sort-reverse'
+    rescue LoadError
+      # rcov not installed
+    end
+  end
+rescue LoadError
+  # rspec not installed
+end