SerializingObject: Document purpose of normalizing methods

[etc/taskwarrior.git] / tasklib / task.py

diff --git a/tasklib/task.py b/tasklib/task.py
index 73280b0cf447bb6e1f1f246914ac0916ae2130ec..537c79291363edee5e2dec8679c2873af936fe17 100644 (file)
--- a/tasklib/task.py
+++ b/tasklib/task.py
@@ -28,6 +28,40 @@ class TaskWarriorException(Exception):
     pass
 
 
+class ReadOnlyDictView(object):
+    """
+    Provides simplified read-only view upon dict object.
+    """
+
+    def __init__(self, viewed_dict):
+        self.viewed_dict = viewed_dict
+
+    def __getitem__(self, key):
+        return copy.deepcopy(self.viewed_dict.__getitem__(key))
+
+    def __contains__(self, k):
+        return self.viewed_dict.__contains__(k)
+
+    def __iter__(self):
+        for value in self.viewed_dict:
+            yield copy.deepcopy(value)
+
+    def __len__(self):
+        return len(self.viewed_dict)
+
+    def get(self, key, default=None):
+        return copy.deepcopy(self.viewed_dict.get(key, default))
+
+    def has_key(self, key):
+        return self.viewed_dict.has_key(key)
+
+    def items(self):
+        return [copy.deepcopy(v) for v in self.viewed_dict.items()]
+
+    def values(self):
+        return [copy.deepcopy(v) for v in self.viewed_dict.values()]
+
+
 class SerializingObject(object):
     """
     Common ancestor for TaskResource & TaskFilter, since they both
@@ -44,6 +78,15 @@ class SerializingObject(object):
         not export empty-valued attributes) if the attribute
         is not iterable (e.g. list or set), in which case
         a empty iterable should be used.
+
+    Normalizing methods should hold the following contract:
+      - They are used to validate and normalize the user input.
+        Any attribute value that comes from the user (during Task
+        initialization, assignign values to Task attributes, or
+        filtering by user-provided values of attributes) is first
+        validated and normalized using the normalize_{key} method.
+      - If validation or normalization fails, normalizer is expected
+        to raise ValueError.
     """
 
     def _deserialize(self, key, value):
@@ -195,7 +238,13 @@ class SerializingObject(object):
             localized = value
         
         return localized
-            
+
+    def normalize_uuid(self, value):
+        # Enforce sane UUID
+        if not isinstance(value, six.text_type) or value == '':
+            raise ValueError("UUID must be a valid non-empty string.")
+
+        return value
 
 
 class TaskResource(SerializingObject):
@@ -384,6 +433,9 @@ class Task(TaskResource):
                           for (key, value) in six.iteritems(kwargs))
         self._original_data = copy.deepcopy(self._data)
 
+        # Provide read only access to the original data
+        self.original = ReadOnlyDictView(self._original_data)
+
     def __unicode__(self):
         return self['description']
 
@@ -777,14 +829,14 @@ class TaskWarrior(object):
         stdout, stderr = [x.decode('utf-8') for x in p.communicate()]
         return stdout.strip('\n')
 
-    def execute_command(self, args, config_override={}):
+    def execute_command(self, args, config_override={}, allow_failure=True):
         command_args = self._get_command_args(
             args, config_override=config_override)
         logger.debug(' '.join(command_args))
         p = subprocess.Popen(command_args, stdout=subprocess.PIPE,
                              stderr=subprocess.PIPE)
         stdout, stderr = [x.decode('utf-8') for x in p.communicate()]
-        if p.returncode:
+        if p.returncode and allow_failure:
             if stderr.strip():
                 error_msg = stderr.strip().splitlines()[-1]
             else:
@@ -792,7 +844,15 @@ class TaskWarrior(object):
             raise TaskWarriorException(error_msg)
         return stdout.strip().split('\n')
 
+    def enforce_recurrence(self):
+        # Run arbitrary report command which will trigger generation
+        # of recurrent tasks.
+        # TODO: Make a version dependant enforcement once
+        #       TW-1531 is handled
+        self.execute_command(['next'], allow_failure=False)
+
     def filter_tasks(self, filter_obj):
+        self.enforce_recurrence()
         args = ['export', '--'] + filter_obj.get_filter_params()
         tasks = []
         for line in self.execute_command(args):