formatter: add condwrite method

This makes handling conditional output tidier

mercurial/formatter.py

@@ -1,72 +1,80 b''
 # formatter.py - generic output formatting for mercurial
 #
 # Copyright 2012 Matt Mackall <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 class baseformatter(object):
     def __init__(self, ui, topic, opts):
         self._ui = ui
         self._topic = topic
         self._style = opts.get("style")
         self._template = opts.get("template")
         self._item = None
     def __bool__(self):
         '''return False if we're not doing real templating so we can
         skip extra work'''
         return True
     def _showitem(self):
         '''show a formatted item once all data is collected'''
         pass
     def startitem(self):
         '''begin an item in the format list'''
         if self._item is not None:
             self._showitem()
         self._item = {}
     def data(self, **data):
         '''insert data into item that's not shown in default output'''
         self._item.update(data)
     def write(self, fields, deftext, *fielddata, **opts):
         '''do default text output while assigning data to item'''
         for k, v in zip(fields.split(), fielddata):
             self._item[k] = v
+    def condwrite(self, cond, fields, deftext, *fielddata, **opts):
+        '''do conditional write (primarily for plain formatter)'''
+        for k, v in zip(fields.split(), fielddata):
+            self._item[k] = v
     def plain(self, text, **opts):
         '''show raw text for non-templated mode'''
         pass
     def end(self):
         '''end output for the formatter'''
         if self._item is not None:
             self._showitem()
 
 class plainformatter(baseformatter):
     '''the default text output scheme'''
     def __init__(self, ui, topic, opts):
         baseformatter.__init__(self, ui, topic, opts)
     def __bool__(self):
         return False
     def startitem(self):
         pass
     def data(self, **data):
         pass
     def write(self, fields, deftext, *fielddata, **opts):
         self._ui.write(deftext % fielddata, **opts)
+    def condwrite(self, cond, fields, deftext, *fielddata, **opts):
+        '''do conditional write'''
+        if cond:
+            self._ui.write(deftext % fielddata, **opts)
     def plain(self, text, **opts):
         self._ui.write(text, **opts)
     def end(self):
         pass
 
 class debugformatter(baseformatter):
     def __init__(self, ui, topic, opts):
         baseformatter.__init__(self, ui, topic, opts)
         self._ui.write("%s = {\n" % self._topic)
     def _showitem(self):
         self._ui.write("    " + repr(self._item) + ",\n")
     def end(self):
         baseformatter.end(self)
         self._ui.write("}\n")
 
 def formatter(ui, topic, opts):
     if ui.configbool('ui', 'formatdebug'):
         return debugformatter(ui, topic, opts)
     return plainformatter(ui, topic, opts)