diff -r f0e521487903 -r 61d6a4caa963 entities/adapters.py
--- a/entities/adapters.py	Thu Jun 10 16:57:02 2010 +0200
+++ b/entities/adapters.py	Thu Jun 10 18:28:12 2010 +0200
@@ -29,7 +29,7 @@
 
 from cubicweb.view import EntityAdapter, implements_adapter_compat
 from cubicweb.selectors import implements, relation_possible
-from cubicweb.interfaces import IDownloadable, ITree
+from cubicweb.interfaces import IDownloadable, ITree, IProgress, IMileStone
 
 
 class IEmailableAdapter(EntityAdapter):
@@ -327,3 +327,109 @@
         path.reverse()
         return path
 
+
+class IProgressAdapter(EntityAdapter):
+    """something that has a cost, a state and a progression.
+
+    You should at least override progress_info an in_progress methods on concret
+    implementations.
+    """
+    __regid__ = 'IProgress'
+    __select__ = implements(IProgress) # XXX for bw compat, should be abstract
+
+    @property
+    @implements_adapter_compat('IProgress')
+    def cost(self):
+        """the total cost"""
+        return self.progress_info()['estimated']
+
+    @property
+    @implements_adapter_compat('IProgress')
+    def revised_cost(self):
+        return self.progress_info().get('estimatedcorrected', self.cost)
+
+    @property
+    @implements_adapter_compat('IProgress')
+    def done(self):
+        """what is already done"""
+        return self.progress_info()['done']
+
+    @property
+    @implements_adapter_compat('IProgress')
+    def todo(self):
+        """what remains to be done"""
+        return self.progress_info()['todo']
+
+    @implements_adapter_compat('IProgress')
+    def progress_info(self):
+        """returns a dictionary describing progress/estimated cost of the
+        version.
+
+        - mandatory keys are (''estimated', 'done', 'todo')
+
+        - optional keys are ('notestimated', 'notestimatedcorrected',
+          'estimatedcorrected')
+
+        'noestimated' and 'notestimatedcorrected' should default to 0
+        'estimatedcorrected' should default to 'estimated'
+        """
+        raise NotImplementedError
+
+    @implements_adapter_compat('IProgress')
+    def finished(self):
+        """returns True if status is finished"""
+        return not self.in_progress()
+
+    @implements_adapter_compat('IProgress')
+    def in_progress(self):
+        """returns True if status is not finished"""
+        raise NotImplementedError
+
+    @implements_adapter_compat('IProgress')
+    def progress(self):
+        """returns the % progress of the task item"""
+        try:
+            return 100. * self.done / self.revised_cost
+        except ZeroDivisionError:
+            # total cost is 0 : if everything was estimated, task is completed
+            if self.progress_info().get('notestimated'):
+                return 0.
+            return 100
+
+    @implements_adapter_compat('IProgress')
+    def progress_class(self):
+        return ''
+
+
+class IMileStoneAdapter(IProgressAdapter):
+    __regid__ = 'IMileStone'
+    __select__ = implements(IMileStone) # XXX for bw compat, should be abstract
+
+    parent_type = None # specify main task's type
+
+    @implements_adapter_compat('IMileStone')
+    def get_main_task(self):
+        """returns the main ITask entity"""
+        raise NotImplementedError
+
+    @implements_adapter_compat('IMileStone')
+    def initial_prevision_date(self):
+        """returns the initial expected end of the milestone"""
+        raise NotImplementedError
+
+    @implements_adapter_compat('IMileStone')
+    def eta_date(self):
+        """returns expected date of completion based on what remains
+        to be done
+        """
+        raise NotImplementedError
+
+    @implements_adapter_compat('IMileStone')
+    def completion_date(self):
+        """returns date on which the subtask has been completed"""
+        raise NotImplementedError
+
+    @implements_adapter_compat('IMileStone')
+    def contractors(self):
+        """returns the list of persons supposed to work on this task"""
+        raise NotImplementedError