Add the option to autoincrement integer values

8 files changed, 84 insertions, 3 deletions

diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index dd24d2e..7485d5b 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -12,6 +12,7 @@ Unreleased
 * Added support to sort the list of all entries.
 * Add the option to autofill date and datetime fields at creation and
   update time.  (#1)
+* Add the option to autoincrement integer values.
 
 0.7.0
 =====
diff --git a/docs/source/user/settings.rst b/docs/source/user/settings.rst
index fead752..c781f11 100644
--- a/docs/source/user/settings.rst
+++ b/docs/source/user/settings.rst
@@ -67,6 +67,25 @@ Some field types may add other custom properties.
    you can use the ``yaml`` generic type, or write your own derivative
    with an additional type).
 
+``integer`` properties
+----------------------
+
+``auto``:
+   automatic manipulation of the field contents.
+
+   The value of ``increment`` will autoincrement the value at every
+   update.
+
+   The reference client will run this update before editing an entry,
+   allowing further changes from the user; a command line user can then
+   decide to abort this change through the usual git commands.
+
+   Other clients may decide to use a different workflow.
+
+``increment``:
+   the amount by which an ``auto: increment`` field is incremented
+   (negative values are of course allowed).
+
 ``date`` and ``datetime`` properties
 ------------------------------------
 
diff --git a/lesana/types.py b/lesana/types.py
index 7f182ea..da67781 100644
--- a/lesana/types.py
+++ b/lesana/types.py
@@ -133,6 +133,29 @@ class LesanaInt(LesanaType):
         """
         return xapian.sortable_serialise(value)
 
+    def update(self, value):
+        """
+        Return an updated value.
+
+        If the field settings ``auto`` is ``increment`` return the value
+        incremented by the value of the field setting ``increment``
+        (default 1).
+
+        """
+        if self.field.get('auto', False) == 'increment':
+            increment = self.field.get('increment', 1)
+            if int(increment) == increment:
+                return value + increment
+            else:
+                logging.warning(
+                    "Invalid configuration value for increment in field %s: "
+                    + "%s",
+                    self.field['name'],
+                    increment,
+                )
+
+        return value
+
 
 class LesanaFloat(LesanaType):
     """
diff --git a/tests/data/complex/items/5084bc6e94f24dc6976629282ef30419.yaml b/tests/data/complex/items/5084bc6e94f24dc6976629282ef30419.yaml
index bb97781..3132884 100644
--- a/tests/data/complex/items/5084bc6e94f24dc6976629282ef30419.yaml
+++ b/tests/data/complex/items/5084bc6e94f24dc6976629282ef30419.yaml
@@ -16,4 +16,5 @@ order: delta
 created:
 updated:
 epoch:
+version: 0
 # and a comment at the end
diff --git a/tests/data/complex/items/8e9fa1ed3c1b4a30a6be7a98eda0cfa7.yaml b/tests/data/complex/items/8e9fa1ed3c1b4a30a6be7a98eda0cfa7.yaml
index 44d8b89..690b680 100644
--- a/tests/data/complex/items/8e9fa1ed3c1b4a30a6be7a98eda0cfa7.yaml
+++ b/tests/data/complex/items/8e9fa1ed3c1b4a30a6be7a98eda0cfa7.yaml
@@ -14,3 +14,4 @@ order:
 created:
 updated:
 epoch:
+version: 2
diff --git a/tests/data/complex/settings.yaml b/tests/data/complex/settings.yaml
index bf64934..7aaf47b 100644
--- a/tests/data/complex/settings.yaml
+++ b/tests/data/complex/settings.yaml
@@ -48,3 +48,7 @@ fields:
     - name: epoch
       type: datetime
       auto: false
+    - name: version
+      type: integer
+      auto: increment
+      increment: 2
diff --git a/tests/test_collection.py b/tests/test_collection.py
index 527acf9..84c535d 100644
--- a/tests/test_collection.py
+++ b/tests/test_collection.py
@@ -297,7 +297,7 @@ class testComplexCollection(unittest.TestCase):
             self.collection.settings['name'],
             "Fully featured lesana collection",
         )
-        self.assertEqual(len(self.collection.settings['fields']), 13)
+        self.assertEqual(len(self.collection.settings['fields']), 14)
         self.assertIsNotNone(self.collection.stemmer)
         self.assertEqual(len(self.collection.indexed_fields), 8)
 
@@ -424,21 +424,24 @@ class testComplexCollection(unittest.TestCase):
         eid = '5084bc6e94f24dc6976629282ef30419'
         entry = self.collection.entry_from_eid(eid)
         # we keep the old data, and check that the updated field is
-        # empty
+        # empty and the version field is 0
         old_data = entry.data.copy()
         self.assertEqual(entry.data['updated'], None)
+        self.assertEqual(entry.data['version'], 0)
 
         entry.update()
 
         # after the update, fields that were not supposed to be updated
         # are equal to what they were before, while updated has been
         # changed to a datetime in this year (we don't check too deeply
-        # to avoid breaking tests too often with race conditions).
+        # to avoid breaking tests too often with race conditions) and
+        # version has grown to 2.
         for field in ('created', 'epoch'):
             self.assertEqual(old_data[field], entry.data[field])
         now = datetime.datetime.now(datetime.timezone.utc)
         self.assertIsInstance(entry.data['updated'], datetime.datetime)
         self.assertEqual(entry.data['updated'].year, now.year)
+        self.assertEqual(entry.data['version'], 2)
 
 
 class testCollectionWithErrors(unittest.TestCase):
diff --git a/tests/test_types.py b/tests/test_types.py
index 260167c..1efcde1 100644
--- a/tests/test_types.py
+++ b/tests/test_types.py
@@ -82,6 +82,35 @@ class testTypes(unittest.TestCase):
         v = checker.update(10)
         self.assertEqual(v, 10)
 
+    def test_datetime_auto_increment(self):
+        field_def = self._get_field_def('integer')
+        field_def['auto'] = 'increment'
+        checker = types.LesanaInt(field_def, {})
+
+        v = checker.empty()
+        self.assertEqual(v, 0)
+
+        v = checker.update(0)
+        self.assertEqual(v, 1)
+
+        field_def['increment'] = -1
+        checker = types.LesanaInt(field_def, {})
+        v = checker.update(0)
+        self.assertEqual(v, -1)
+
+        field_def['increment'] = 0.5
+        checker = types.LesanaInt(field_def, {})
+        with self.assertLogs() as cm:
+            v = checker.update(0)
+        self.assertIn('WARNING', cm.output[0])
+        self.assertIn('Invalid configuration value', cm.output[0])
+        self.assertEqual(v, 0)
+
+        field_def['auto'] = 'false'
+        checker = types.LesanaInt(field_def, {})
+        v = checker.update(0)
+        self.assertEqual(v, 0)
+
     def test_float(self):
         checker = types.LesanaFloat(self._get_field_def('float'), {})