config_file.rb in mercurial-ruby-0.6.0

- old
+ new

@@ -1,16 +1,18 @@
 module Mercurial
-  
+
   #
   # Represents +.hg/hgrc+ configuration file stored in the repository.
   # Useful for adding/removing various settings.
   #
   # You can read more about hgrc here:
   #
   # http://www.selenic.com/mercurial/hgrc.5.html
   #
   class ConfigFile
+
+    class DuplicateSetting < Error; end
     
     attr_reader :repository
     
     def initialize(repository)
       @repository = repository
@@ -49,10 +51,12 @@
     #
     #  [merge-tools]
     #  kdiff3.executable = ~/bin/kdiff3
     #
     def add_setting(header, name, value)
+      raise DuplicateSetting if setting_exists?(header, name)
+
       new_setting = %Q{[#{ header }]\n#{ name } = #{ value }\n}
       write do
         if contents.nil?
           new_setting
         elsif contents.scan(header_regexp(header)).empty?
@@ -71,10 +75,19 @@
     def delete_setting!(header, name)
       write do 
         contents.gsub(find_setting(header, name), '')
       end
     end
+
+    #
+    # Returns true if specified setting exists in specified group.
+    #
+    #  config.setting_exists?('hooks', 'changegroup')
+    #
+    def setting_exists?(header, name)
+      !!find_setting(header, name)
+    end
     
     #
     # Returns content of the specified section of hgrc.
     #
     def find_header(header)
@@ -88,10 +101,11 @@
     
     #
     # Returns content of the specified setting from a section.
     #
     def find_setting(header, setting) #:nodoc:
+      return nil if contents.nil?
       contents.scan(setting_regexp(header, setting)).flatten.first
     end
     
   private
   
@@ -114,6 +128,6 @@
       /\[#{ Regexp.escape(header) }\]\s*[^\[\]]*(^#{ Regexp.escape(setting) }.+\n*)/i
     end
     
   end
   
-end
\ No newline at end of file
+end