Merge branch 'release/0.12.0' into develop

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

diff --git a/tasklib/backends.py b/tasklib/backends.py
index 32a8018acb142ddb1257e0fe3916089bde2ecf70..76fce88054d53e2a9b5b89e83ee4be9e8125d7ae 100644 (file)
--- a/tasklib/backends.py
+++ b/tasklib/backends.py
@@ -7,9 +7,8 @@ import os
 import re
 import six
 import subprocess
-import copy
 
-from .task import Task, TaskQuerySet
+from .task import Task, TaskQuerySet, ReadOnlyDictView
 from .filters import TaskWarriorFilter
 from .serializing import local_zone
 
@@ -76,7 +75,7 @@ class Backend(object):
         Converts TW syntax datetime string to a localized datetime
         object. This method is not mandatory.
         """
-        raise NotImplemented
+        raise NotImplementedError
 
 
 class TaskWarriorException(Exception):
@@ -103,8 +102,9 @@ class TaskWarrior(Backend):
         if not os.path.exists(self.taskrc_location):
             self.taskrc_location = '/'
 
+        self._config = None
         self.version = self._get_version()
-        self.config = {
+        self.overrides = {
             'confirmation': 'no',
             'dependency.confirmation': 'no',  # See TW-1483 or taskrc man page
             'recurrence.confirmation': 'no',  # Necessary for modifying R tasks
@@ -122,15 +122,15 @@ class TaskWarrior(Backend):
             data_location = os.path.expanduser(data_location)
             if create and not os.path.exists(data_location):
                 os.makedirs(data_location)
-            self.config['data.location'] = data_location
+            self.overrides['data.location'] = data_location
 
         self.tasks = TaskQuerySet(self)
 
     def _get_command_args(self, args, config_override=None):
         command_args = ['task', 'rc:{0}'.format(self.taskrc_location)]
-        config = self.config.copy()
-        config.update(config_override or dict())
-        for item in config.items():
+        overrides = self.overrides.copy()
+        overrides.update(config_override or dict())
+        for item in overrides.items():
             command_args.append('rc.{0}={1}'.format(*item))
         command_args.extend(map(six.text_type, args))
         return command_args
@@ -229,7 +229,13 @@ class TaskWarrior(Backend):
 
     # Public interface
 
-    def get_config(self):
+    @property
+    def config(self):
+        # First, check if memoized information is available
+        if self._config:
+            return self._config
+
+        # If not, fetch the config using the 'show' command
         raw_output = self.execute_command(
             ['show'],
             config_override={'verbose': 'nothing'}
@@ -243,7 +249,10 @@ class TaskWarrior(Backend):
             if match:
                 config[match.group('key')] = match.group('value').strip()
 
-        return config
+        # Memoize the config dict
+        self._config = ReadOnlyDictView(config)
+
+        return self._config
 
     def execute_command(self, args, config_override=None, allow_failure=True,
                         return_all=False):
@@ -289,7 +298,7 @@ class TaskWarrior(Backend):
 
     def filter_tasks(self, filter_obj):
         self.enforce_recurrence()
-        args = ['export', '--'] + filter_obj.get_filter_params()
+        args = ['export'] + filter_obj.get_filter_params()
         tasks = []
         for line in self.execute_command(args):
             if line:
@@ -383,7 +392,7 @@ class TaskWarrior(Backend):
             for key, value in data.items():
                 taskfilter.add_filter_param(key, value)
 
-            output = self.execute_command(['export', '--'] +
+            output = self.execute_command(['export'] +
                                           taskfilter.get_filter_params())
 
         # If more than 1 task has been matched still, raise an exception