1 files changed, 133 insertions, 0 deletions
diff --git a/activesupport/lib/active_support/hash_with_indifferent_access.rb b/activesupport/lib/active_support/hash_with_indifferent_access.rb
new file mode 100644
index 0000000000..61fc6475a0
--- /dev/null
+++ b/activesupport/lib/active_support/hash_with_indifferent_access.rb
@@ -0,0 +1,133 @@
+# This class has dubious semantics and we only have it so that
+# people can write params[:key] instead of params['key']
+# and they get the same value for both keys.
+
+module ActiveSupport
+  class HashWithIndifferentAccess < Hash
+    def initialize(constructor = {})
+      if constructor.is_a?(Hash)
+        super()
+        update(constructor)
+      else
+        super(constructor)
+      end
+    end
+
+    def default(key = nil)
+      if key.is_a?(Symbol) && include?(key = key.to_s)
+        self[key]
+      else
+        super
+      end
+    end
+
+    alias_method :regular_writer, :[]= unless method_defined?(:regular_writer)
+    alias_method :regular_update, :update unless method_defined?(:regular_update)
+
+    # Assigns a new value to the hash:
+    #
+    #   hash = HashWithIndifferentAccess.new
+    #   hash[:key] = "value"
+    #
+    def []=(key, value)
+      regular_writer(convert_key(key), convert_value(value))
+    end
+
+    # Updates the instantized hash with values from the second:
+    #
+    #   hash_1 = HashWithIndifferentAccess.new
+    #   hash_1[:key] = "value"
+    #
+    #   hash_2 = HashWithIndifferentAccess.new
+    #   hash_2[:key] = "New Value!"
+    #
+    #   hash_1.update(hash_2) # => {"key"=>"New Value!"}
+    #
+    def update(other_hash)
+      other_hash.each_pair { |key, value| regular_writer(convert_key(key), convert_value(value)) }
+      self
+    end
+
+    alias_method :merge!, :update
+
+    # Checks the hash for a key matching the argument passed in:
+    #
+    #   hash = HashWithIndifferentAccess.new
+    #   hash["key"] = "value"
+    #   hash.key? :key  # => true
+    #   hash.key? "key" # => true
+    #
+    def key?(key)
+      super(convert_key(key))
+    end
+
+    alias_method :include?, :key?
+    alias_method :has_key?, :key?
+    alias_method :member?, :key?
+
+    # Fetches the value for the specified key, same as doing hash[key]
+    def fetch(key, *extras)
+      super(convert_key(key), *extras)
+    end
+
+    # Returns an array of the values at the specified indices:
+    #
+    #   hash = HashWithIndifferentAccess.new
+    #   hash[:a] = "x"
+    #   hash[:b] = "y"
+    #   hash.values_at("a", "b") # => ["x", "y"]
+    #
+    def values_at(*indices)
+      indices.collect {|key| self[convert_key(key)]}
+    end
+
+    # Returns an exact copy of the hash.
+    def dup
+      HashWithIndifferentAccess.new(self)
+    end
+
+    # Merges the instantized and the specified hashes together, giving precedence to the values from the second hash
+    # Does not overwrite the existing hash.
+    def merge(hash)
+      self.dup.update(hash)
+    end
+
+    # Performs the opposite of merge, with the keys and values from the first hash taking precedence over the second.
+    # This overloaded definition prevents returning a regular hash, if reverse_merge is called on a HashWithDifferentAccess.
+    def reverse_merge(other_hash)
+      super other_hash.with_indifferent_access
+    end
+
+    # Removes a specified key from the hash.
+    def delete(key)
+      super(convert_key(key))
+    end
+
+    def stringify_keys!; self end
+    def symbolize_keys!; self end
+    def to_options!; self end
+
+    # Convert to a Hash with String keys.
+    def to_hash
+      Hash.new(default).merge(self)
+    end
+
+    protected
+      def convert_key(key)
+        key.kind_of?(Symbol) ? key.to_s : key
+      end
+
+      def convert_value(value)
+        case value
+        when Hash
+          value.with_indifferent_access
+        when Array
+          value.collect { |e| e.is_a?(Hash) ? e.with_indifferent_access : e }
+        else
+          value
+        end
+      end
+  end
+end
+
+HashWithIndifferentAccess = ActiveSupport::HashWithIndifferentAccess