From 1520353fc2fac441514651f0a441577a241820ad Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Valim?= <jose.valim@gmail.com>
Date: Wed, 27 Apr 2011 20:55:03 +0200
Subject: [PATCH] Add inputs discovery.

---
 Gemfile                         |  2 +-
 Gemfile.lock                    |  6 ++--
 lib/simple_form.rb              |  8 +++++
 lib/simple_form/form_builder.rb | 53 +++++++++++++++++++++++++++++++--
 test/test_helper.rb             |  6 ++++
 5 files changed, 69 insertions(+), 6 deletions(-)

diff --git a/Gemfile b/Gemfile
index 9d1f3e7d..a0a3e40f 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,6 +1,6 @@
 source "http://rubygems.org"
 
-gem "rails", "~> 3.0.0"
+gem "rails", "~> 3.0.7"
 
 group :test do
   gem "mocha",      :require => false
diff --git a/Gemfile.lock b/Gemfile.lock
index 6dac6d8f..d973be12 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -35,7 +35,7 @@ GEM
       abstract (>= 1.0.0)
     i18n (0.5.0)
     linecache (0.43)
-    mail (2.2.17)
+    mail (2.2.18)
       activesupport (>= 2.3.6)
       i18n (>= 0.4.0)
       mime-types (~> 1.16)
@@ -71,12 +71,12 @@ GEM
     thor (0.14.6)
     treetop (1.4.9)
       polyglot (>= 0.3.1)
-    tzinfo (0.3.26)
+    tzinfo (0.3.27)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
   mocha
-  rails (~> 3.0.0)
+  rails (~> 3.0.7)
   ruby-debug
diff --git a/lib/simple_form.rb b/lib/simple_form.rb
index 5076ff09..fe3d8d32 100644
--- a/lib/simple_form.rb
+++ b/lib/simple_form.rb
@@ -128,6 +128,14 @@ module SimpleForm
   mattr_accessor :translate
   @@translate = true
 
+  # Automatically discover new inputs in Rails' autoload path.
+  mattr_accessor :inputs_discovery
+  @@inputs_discovery = true
+
+  # Cache simple form inputs discovery
+  mattr_accessor :cache_discovery
+  @@cache_discovery = !Rails.env.development?
+
   # Default way to setup SimpleForm. Run rails generate simple_form:install
   # to create a fresh initializer with all configuration values.
   def self.setup
diff --git a/lib/simple_form/form_builder.rb b/lib/simple_form/form_builder.rb
index b6f4989d..e5d70f35 100644
--- a/lib/simple_form/form_builder.rb
+++ b/lib/simple_form/form_builder.rb
@@ -13,6 +13,10 @@ module SimpleForm
     map_type :country, :time_zone,                            :to => SimpleForm::Inputs::PriorityInput
     map_type :boolean,                                        :to => SimpleForm::Inputs::BooleanInput
 
+    def self.discovery_cache
+      @discovery_cache ||= {}
+    end
+
     # Basic input helper, combines all components in the stack to generate
     # input html based on options the user define and some guesses through
     # database column information. By default a call to input will generate
@@ -85,8 +89,7 @@ module SimpleForm
       if block_given?
         SimpleForm::Inputs::BlockInput.new(self, attribute_name, column, input_type, options, &block).render
       else
-        klass = self.class.mappings[input_type] || self.class.const_get("#{input_type.to_s.camelize}Input")
-        klass.new(self, attribute_name, column, input_type, options).render
+        find_mapping(input_type).new(self, attribute_name, column, input_type, options).render
       end
     end
     alias :attribute :input
@@ -314,5 +317,51 @@ module SimpleForm
         @object.class.reflect_on_association(association)
       end
     end
+
+    # Attempts to find a mapping. It follows the following rules:
+    #
+    # 1) It tries to find a registered mapping, if succeeds:
+    #    a) If a mapping is found, try to find an alternative as #{mapping}Input
+    #    b) Or use the found mapping
+    # 2) If not, fallbacks to #{input_type}Input
+    # 3) If not, fallbacks to SimpleForm::Inputs::#{input_type}
+    def find_mapping(input_type) #:nodoc:
+      discovery_cache[input_type] ||=
+        if mapping = self.class.mappings[input_type]
+          mapping_override(mapping) || mapping
+        else
+          camelized = "#{input_type.to_s.camelize}Input"
+          attempt_mapping(camelized, Object) || attempt_mapping(camelized, self.class) ||
+            raise("No input found for #{input_type}")
+        end
+    end
+
+    # If cache_discovery is enabled, use the class level cache that persists
+    # between requests, otherwise use the instance one.
+    def discovery_cache #:nodoc:
+      if SimpleForm.cache_discovery
+        self.class.discovery_cache
+      else
+        @discovery_cache ||= {}
+      end
+    end
+
+    def mapping_override(klass) #:nodoc:
+      name = klass.name
+      if name =~ /^SimpleForm::Inputs/
+        attempt = "#{name.split("::").last}Input"
+        attempt_mapping attempt, Object
+      end
+    end
+
+    def attempt_mapping(mapping, at) #:nodoc:
+      return if SimpleForm.inputs_discovery == false && at == Object
+
+      begin
+        at.const_get(mapping)
+      rescue NameError => e
+        e.message =~ /#{mapping}$/ ? nil : raise
+      end
+    end
   end
 end
diff --git a/test/test_helper.rb b/test/test_helper.rb
index 6c1b686a..e3d2e884 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -13,6 +13,12 @@ require 'action_view/template'
 require 'active_support/core_ext/module/deprecation'
 require 'action_view/test_case'
 
+module Rails
+  def self.env
+    ActiveSupport::StringInquirer.new("test")
+  end
+end
+
 $:.unshift File.expand_path("../../lib", __FILE__)
 require 'simple_form'