Add digits mixin

issue10596
review338511002

CHANGELOG

@@ -1,3 +1,4 @@
+* Add digits mixin
 * Use argon2 or scrypt to hash password by default
 * Allow PYSON Expression as key for PYSON In with dict object
 * Add method to format warning name with records

doc/ref/models/fields.rst

@@ -383,6 +383,8 @@ instance.
     Integers can be replaced by a :class:`~trytond.pyson.PYSON` statement.
     If digits is None or any values of the tuple is ``None``, no validation on
     the numbers will be done.
+    The tuple can be replaced by a string containing the name of a
+    :class:`Many2One` pointing to a :class:`DigitsMixin`.
 
 Numeric
 -------

doc/ref/models/models.rst

@@ -802,6 +802,21 @@ Instance methods:
     (1) the value. If no symbol parameter is supplied then the mixin uses the
     value of attribute named ``symbol``.
 
+===========
+DigitsMixin
+===========
+
+.. class:: DigitsMixin
+
+A mixin_ to manage the digits of :attr:`Float.digits` and
+:attr:`Numeric.digits` from a :class:`Model`.
+
+Instance methods:
+
+.. method:: DigitsMixin.get_digits()
+
+   Return a tuple of two integers to use a ``digits`` attribute.
+
 ================
 sequence_ordered
 ================

trytond/model/__init__.py

@@ -10,6 +10,7 @@ from .dictschema import DictSchemaMixin
 from .match import MatchMixin
 from .union import UnionMixin
 from .symbol import SymbolMixin
+from .digits import DigitsMixin
 from .multivalue import MultiValueMixin, ValueMixin
 from .descriptors import dualmethod
 from .order import sequence_ordered
@@ -20,6 +21,6 @@ from .avatar import avatar_mixin
 __all__ = ['Model', 'ModelView', 'ModelStorage', 'ModelSingleton', 'ModelSQL',
     'Check', 'Unique', 'Exclude',
     'Workflow', 'DictSchemaMixin', 'MatchMixin', 'UnionMixin', 'dualmethod',
-    'MultiValueMixin', 'ValueMixin', 'SymbolMixin',
+    'MultiValueMixin', 'ValueMixin', 'SymbolMixin', 'DigitsMixin',
     'EvalEnvironment', 'sequence_ordered', 'DeactivableMixin', 'tree',
     'avatar_mixin']

trytond/model/digits.py

@@ -0,0 +1,34 @@
+# This file is part of Tryton.  The COPYRIGHT file at the top level of
+# this repository contains the full copyright notices and license terms.
+from trytond.cache import Cache
+from trytond.rpc import RPC
+
+
+class DigitsMixin:
+    __slots__ = ()
+
+    _digits_cache = Cache('_digits_mixin..get_digits', context=False)
+
+    @classmethod
+    def __setup__(cls):
+        super().__setup__()
+        cls.__rpc__.update({
+                'get_digits': RPC(instantiate=0, cache=dict(days=1)),
+                })
+
+    def get_digits(self):
+        key = str(self)
+        digits = self._digits_cache.get(key)
+        if digits is not None:
+            return digits
+        digits = self._get_digits()
+        self._digits_cache.set(key, digits)
+        return digits
+
+    def _get_digits(self):
+        return (16, self.digits)
+
+    @classmethod
+    def write(cls, *args):
+        super().write(*args)
+        cls._digits_cache.clear()

trytond/model/fields/float.py

@@ -6,13 +6,15 @@ from .field import Field
 
 def digits_validate(value):
     if value:
-        assert isinstance(value, tuple), 'digits must be a tuple'
-        for i in value:
-            assert isinstance(i, (int, PYSON)), \
-                'digits must be tuple of integers or PYSON'
-            if isinstance(i, PYSON):
-                assert i.types().issubset(set([int, int])), \
-                    'PYSON digits must return an integer'
+        assert isinstance(value, (tuple, str)), \
+                'digits must be a tuple or a string'
+        if isinstance(value, tuple):
+            for i in value:
+                assert isinstance(i, (int, PYSON)), \
+                    'digits must be tuple of integers or PYSON'
+                if isinstance(i, PYSON):
+                    assert i.types().issubset(set([int, int])), \
+                        'PYSON digits must return an integer'
 
 
 class Float(Field):
@@ -31,6 +33,12 @@ class Float(Field):
         :param digits: a list of two integers defining the total
             of digits and the number of decimals of the float.
         '''
+        if isinstance(digits, str):
+            if depends is None:
+                depends = [digits]
+            elif digits not in depends:
+                depends = depends.copy()
+                depends.append(digits)
         super(Float, self).__init__(string=string, help=help,
             required=required, readonly=readonly, domain=domain, states=states,
             select=select, on_change=on_change, on_change_with=on_change_with,

trytond/model/modelstorage.py

@@ -1268,7 +1268,7 @@ class ModelStorage(Model):
                                 gettext('ir.msg_size_validation_record',
                                     **error_args))
 
-                def digits_test(value, digits, field_name):
+                def digits_test(record, digits, field_name):
                     def raise_error(value):
                         error_args = cls.__names__(field_name)
                         error_args['digits'] = digits[1]
@@ -1276,6 +1276,14 @@ class ModelStorage(Model):
                         raise DigitsValidationError(
                             gettext('ir.msg_digits_validation_record',
                                 **error_args))
+
+                    value = getattr(record, field_name)
+                    if isinstance(digits, str):
+                        digit_record = getattr(record, digits)
+                        if digit_record:
+                            digits = digit_record.get_digits()
+                        else:
+                            digits = None
                     if (value is None
                             or not digits
                             or any(d is None for d in digits)):
@@ -1294,12 +1302,10 @@ class ModelStorage(Model):
                         for record in records:
                             digits = _record_eval_pyson(
                                 record, pyson_digits, encoded=True)
-                            digits_test(getattr(record, field_name), digits,
-                                field_name)
+                            digits_test(record, digits, field_name)
                     else:
                         for record in records:
-                            digits_test(getattr(record, field_name),
-                                field.digits, field_name)
+                            digits_test(record, field.digits, field_name)
 
                 if hasattr(field, 'forbidden_chars'):
                     for record in records:

trytond/tests/test_tryton.py

@@ -338,7 +338,10 @@ class ModuleTestCase(unittest.TestCase):
                 fields = set()
                 fields |= get_eval_fields(field.domain)
                 if hasattr(field, 'digits'):
-                    fields |= get_eval_fields(field.digits)
+                    if isinstance(field.digits, str):
+                        fields.add(field.digits)
+                    else:
+                        fields |= get_eval_fields(field.digits)
                 if hasattr(field, 'add_remove'):
                     fields |= get_eval_fields(field.add_remove)
                 if hasattr(field, 'size'):