Now allow every type of locales + archlinux fix

The previous version of this code was supporting only locales using the
format "<language>_<territory>.<charset>". But all the locales that
doesn't have this format were not installable (such as "fr_FR" or
"fr_FR@euro").
Also, if an invalid locales was provided, the module kept sending a
"changed" status.

Now :
 * if the user provides an invalid locales, the module failed. Locales
   are verified using /etc/locale.gen or /usr/share/i18n/SUPPORTED if
   Ubuntu
 * Every types of valid locales are now supported.
 * The locale module was not working on Archlinux, as there's no space
   between the "#" and the locale. This is now supported. Credits goes
   to danderson189, this is his code.

This module was tested on debian jessie, ubuntu 14 LTS and last
Archlinux.

system/locale_gen.py

@@ -36,6 +36,26 @@ EXAMPLES = '''
 # location module specific support methods.
 #
 
+def is_available(name, ubuntuMode):
+    """Check if the given locale is available on the system. This is done by
+    checking either :
+    * if the locale is present in /etc/locales.gen
+    * or if the locale is present in /usr/share/i18n/SUPPORTED"""
+    if ubuntuMode:
+        __regexp = '^(?P<locale>\S+_\S+) (?P<charset>\S+)\s*$'
+        __locales_available = '/usr/share/i18n/SUPPORTED'
+    else:
+        __regexp = '^#{0,1}\s*(?P<locale>\S+_\S+) (?P<charset>\S+)\s*$'
+        __locales_available = '/etc/locale.gen'
+
+    re_compiled = re.compile(__regexp)
+    with open(__locales_available, 'r') as fd:
+        for line in fd:
+            result = re_compiled.match(line)
+            if result and result.group('locale') == name:
+                return True
+    return False
+
 def is_present(name):
     """Checks if the given locale is currently installed."""
     output = Popen(["locale", "-a"], stdout=PIPE).communicate()[0]
@@ -53,32 +73,42 @@ def replace_line(existing_line, new_line):
     with open("/etc/locale.gen", "w") as f:
         f.write("".join(lines))
 
-def apply_change(targetState, name, encoding):
+def set_locale(name, enabled=True):
+    """ Sets the state of the locale. Defaults to enabled. """
+    search_string = '#{0,1}\s*%s (?P<charset>.+)' % name
+    if enabled:
+        new_string = '%s \g<charset>' % (name)
+    else:
+        new_string = '# %s \g<charset>' % (name)
+    with open("/etc/locale.gen", "r") as f:
+        lines = [re.sub(search_string, new_string, line) for line in f]
+    with open("/etc/locale.gen", "w") as f:
+        f.write("".join(lines))
+
+def apply_change(targetState, name):
     """Create or remove locale.
-    
+
     Keyword arguments:
     targetState -- Desired state, either present or absent.
     name -- Name including encoding such as de_CH.UTF-8.
-    encoding -- Encoding such as UTF-8.
     """
     if targetState=="present":
         # Create locale.
-        replace_line("# "+name+" "+encoding, name+" "+encoding)
+        set_locale(name, enabled=True)
     else:
         # Delete locale.
-        replace_line(name+" "+encoding, "# "+name+" "+encoding)
+        set_locale(name, enabled=False)
     
     localeGenExitValue = call("locale-gen")
     if localeGenExitValue!=0:
         raise EnvironmentError(localeGenExitValue, "locale.gen failed to execute, it returned "+str(localeGenExitValue))
 
-def apply_change_ubuntu(targetState, name, encoding):
+def apply_change_ubuntu(targetState, name):
     """Create or remove locale.
     
     Keyword arguments:
     targetState -- Desired state, either present or absent.
     name -- Name including encoding such as de_CH.UTF-8.
-    encoding -- Encoding such as UTF-8.
     """
     if targetState=="present":
         # Create locale.
@@ -90,7 +120,8 @@ def apply_change_ubuntu(targetState, name, encoding):
             content = f.readlines()
         with open("/var/lib/locales/supported.d/local", "w") as f:
             for line in content:
-                if line!=(name+" "+encoding+"\n"):
+                locale, charset = line.split(' ')
+                if locale != name:
                     f.write(line)
         # Purge locales and regenerate.
         # Please provide a patch if you know how to avoid regenerating the locales to keep!
@@ -113,8 +144,6 @@ def main():
     )
 
     name = module.params['name']
-    if not "." in name:
-        module.fail_json(msg="Locale does not match pattern. Did you specify the encoding?")
     state = module.params['state']
 
     if not os.path.exists("/etc/locale.gen"):
@@ -126,23 +155,26 @@ def main():
     else:
         # We found the common way to manage locales.
         ubuntuMode = False
-    
+
+    if not is_available(name, ubuntuMode):
+        module.fail_json(msg="The locales you've entered is not available "
+                             "on your system.")
+
     prev_state = "present" if is_present(name) else "absent"
     changed = (prev_state!=state)
     
     if module.check_mode:
         module.exit_json(changed=changed)
     else:
-        encoding = name.split(".")[1]
         if changed:
             try:
                 if ubuntuMode==False:
-                    apply_change(state, name, encoding)
+                    apply_change(state, name)
                 else:
-                    apply_change_ubuntu(state, name, encoding)
+                    apply_change_ubuntu(state, name)
             except EnvironmentError as e:
                 module.fail_json(msg=e.strerror, exitValue=e.errno)
-      
+
         module.exit_json(name=name, changed=changed, msg="OK")
 
 # import module snippets