Initial commit

env/lib/python3.10/site-packages/modelcluster/datetime_utils.py

@@ -0,0 +1,119 @@
+import datetime
+
+from django import forms
+
+
+TIMEFIELD_TRANSFORM_EXPRESSIONS = {"hour", "minute", "second"}
+DATEFIELD_TRANSFORM_EXPRESSIONS = {
+    "year",
+    "iso_year",
+    "month",
+    "day",
+    "week",
+    "week_day",
+    "iso_week_day",
+    "quarter",
+}
+DATETIMEFIELD_TRANSFORM_EXPRESSIONS = (
+    {"date", "time"}
+    | TIMEFIELD_TRANSFORM_EXPRESSIONS
+    | DATEFIELD_TRANSFORM_EXPRESSIONS
+)
+TRANSFORM_FIELD_TYPES = {
+    "year": forms.IntegerField,
+    "iso_year": forms.IntegerField,
+    "month": forms.IntegerField,
+    "hour": forms.IntegerField,
+    "minute": forms.IntegerField,
+    "second": forms.IntegerField,
+    "day": forms.IntegerField,
+    "week": forms.IntegerField,
+    "week_day": forms.IntegerField,
+    "iso_week_day": forms.IntegerField,
+    "quarter": forms.IntegerField,
+    "date": forms.DateField,
+    "time": forms.TimeField,
+}
+
+
+def derive_from_value(value, expr):
+    if isinstance(value, datetime.datetime):
+        return derive_from_datetime(value, expr)
+    if isinstance(value, datetime.date):
+        return derive_from_date(value, expr)
+    if isinstance(value, datetime.time):
+        return derive_from_time(value, expr)
+    return None
+
+
+def derive_from_time(value, expr):
+    """
+    Mimics the behaviour of the ``hour``, ``minute`` and ``second`` lookup
+    expressions that Django querysets support for ``TimeField`` and
+    ``DateTimeField``, by extracting the relevant value from an in-memory
+    ``time`` or ``datetime`` value.
+    """
+    if expr == "hour":
+        return value.hour
+    if expr == "minute":
+        return value.minute
+    if expr == "second":
+        return value.second
+    raise ValueError(
+        "Expression '{expression}' is not supported for {value}".format(
+            expression=expr, value=repr(value)
+        )
+    )
+
+
+def derive_from_date(value, expr):
+    """
+    Mimics the behaviour of the ``year``, ``iso_year`` ``month``, ``day``,
+    ``week``, ``week_day``, ``iso_week_day`` and ``quarter`` lookup
+    expressions that Django querysets support for ``DateField`` and
+    ``DateTimeField`` columns, by extracting the relevant value from an
+    in-memory ``date`` or ``datetime`` value.
+    """
+    if expr == "year":
+        return value.year
+    if expr == "iso_year":
+        return value.isocalendar()[0]
+    if expr == "month":
+        return value.month
+    if expr == "day":
+        return value.day
+    if expr == "week":
+        return value.isocalendar()[1]
+    if expr == "week_day":
+        v = value.isoweekday()
+        return 1 if v == 7 else v + 1
+    if expr == "iso_week_day":
+        return value.isoweekday()
+    if expr == "quarter":
+        return (value.month - 1) // 3 + 1
+    raise ValueError(
+        "Expression '{expression}' is not supported for {value}".format(
+            expression=expr, value=repr(value)
+        )
+    )
+
+
+def derive_from_datetime(value, expr):
+    """
+    Mimics the behaviour of the ``date``, ``time`` and other lookup
+    expressions that Django querysets support for ``DateTimeField`` columns,
+    by extracting the relevant value from an in-memory ``datetime`` value.
+    """
+    if expr == "date":
+        return value.date()
+    if expr == "time":
+        return value.time()
+    if expr in TIMEFIELD_TRANSFORM_EXPRESSIONS:
+        return derive_from_time(value, expr)
+    if expr in DATEFIELD_TRANSFORM_EXPRESSIONS:
+        return derive_from_date(value, expr)
+    raise ValueError(
+        "Expression '{expression}' is not supported for {value}".format(
+            expression=expr, value=repr(value)
+        )
+    )