From e632abed41c5cd71507c4222e1e85987556b232c Mon Sep 17 00:00:00 2001
From: David Douard <david.douard@sdfa3.org>
Date: Wed, 13 May 2020 17:03:01 +0200
Subject: [PATCH] Tag model entities with their "object_type"
this aims at preventing constant usage of isinstance() based dispatch
code when writing generic code handling model entities.
For example, the "object_type" argument of JournalWriter.write_addition() has
become superflous now we only pass model entities, etc.
This idea comes olasd's reading of mypy doc:
https://mypy.readthedocs.io/en/latest/literal_types.html#tagged-unions
This comes with a refactoring of from_dict.DiskBackedContent to make
it *not* inherit from model.Content: object_type being Final, it cannot
be overloaded.
---
requirements.txt | 5 +++--
swh/model/from_disk.py | 33 +++++++++++++++++++++++++++++++--
swh/model/model.py | 31 ++++++++++++++++++++++++++++++-
swh/model/tests/test_model.py | 22 ++++++++++++++++++++++
4 files changed, 86 insertions(+), 5 deletions(-)
diff --git a/requirements.txt b/requirements.txt
index c2d38df1..b70187b2 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,9 +1,10 @@
# Add here external Python modules dependencies, one per line. Module names
# should match https://pypi.python.org/pypi names. For the full spec or
# dependency lines, see https://pip.readthedocs.org/en/1.1/requirements.html
-vcversioner
attrs
attrs_strict >= 0.0.7
hypothesis
-python-dateutil
iso8601
+python-dateutil
+typing_extensions
+vcversioner
diff --git a/swh/model/from_disk.py b/swh/model/from_disk.py
index 5176dc9e..da559121 100644
--- a/swh/model/from_disk.py
+++ b/swh/model/from_disk.py
@@ -3,12 +3,15 @@
# License: GNU General Public License version 3, or any later version
# See top-level LICENSE file for more information
+import datetime
import enum
import os
import stat
import attr
+from attrs_strict import type_validator
from typing import List, Optional, Iterable, Any
+from typing_extensions import Final
from .hashutil import MultiHash
from .merkle import MerkleLeaf, MerkleNode
@@ -22,11 +25,37 @@ from . import model
@attr.s
-class DiskBackedContent(model.Content):
- """Subclass of Content, which allows lazy-loading data from the disk."""
+class DiskBackedContent(model.BaseContent):
+ """Content-like class, which allows lazy-loading data from the disk."""
+
+ object_type: Final = "content_file"
+
+ sha1 = attr.ib(type=bytes, validator=type_validator())
+ sha1_git = attr.ib(type=model.Sha1Git, validator=type_validator())
+ sha256 = attr.ib(type=bytes, validator=type_validator())
+ blake2s256 = attr.ib(type=bytes, validator=type_validator())
+
+ length = attr.ib(type=int, validator=type_validator())
+
+ status = attr.ib(
+ type=str,
+ validator=attr.validators.in_(["visible", "hidden"]),
+ default="visible",
+ )
+
+ ctime = attr.ib(
+ type=Optional[datetime.datetime],
+ validator=type_validator(),
+ default=None,
+ eq=False,
+ )
path = attr.ib(type=Optional[bytes], default=None)
+ @classmethod
+ def from_dict(cls, d):
+ return cls(**d)
+
def __attrs_post_init__(self):
if self.path is None:
raise TypeError("path must not be None.")
diff --git a/swh/model/model.py b/swh/model/model.py
index 220733f4..bffe711d 100644
--- a/swh/model/model.py
+++ b/swh/model/model.py
@@ -1,4 +1,4 @@
-# Copyright (C) 2018-2019 The Software Heritage developers
+# Copyright (C) 2018-2020 The Software Heritage developers
# See the AUTHORS file at the top-level directory of this distribution
# License: GNU General Public License version 3, or any later version
# See top-level LICENSE file for more information
@@ -9,6 +9,7 @@ from abc import ABCMeta, abstractmethod
from enum import Enum
from hashlib import sha256
from typing import Dict, Optional, Tuple, TypeVar, Union
+from typing_extensions import Final
import attr
from attrs_strict import type_validator
@@ -101,6 +102,8 @@ class HashableObject(metaclass=ABCMeta):
class Person(BaseModel):
"""Represents the author/committer of a revision or release."""
+ object_type: Final = "person"
+
fullname = attr.ib(type=bytes, validator=type_validator())
name = attr.ib(type=Optional[bytes], validator=type_validator())
email = attr.ib(type=Optional[bytes], validator=type_validator())
@@ -153,6 +156,8 @@ class Person(BaseModel):
class Timestamp(BaseModel):
"""Represents a naive timestamp from a VCS."""
+ object_type: Final = "timestamp"
+
seconds = attr.ib(type=int, validator=type_validator())
microseconds = attr.ib(type=int, validator=type_validator())
@@ -173,6 +178,8 @@ class Timestamp(BaseModel):
class TimestampWithTimezone(BaseModel):
"""Represents a TZ-aware timestamp from a VCS."""
+ object_type: Final = "timestamp_with_timezone"
+
timestamp = attr.ib(type=Timestamp, validator=type_validator())
offset = attr.ib(type=int, validator=type_validator())
negative_utc = attr.ib(type=bool, validator=type_validator())
@@ -223,6 +230,8 @@ class TimestampWithTimezone(BaseModel):
class Origin(BaseModel):
"""Represents a software source: a VCS and an URL."""
+ object_type: Final = "origin"
+
url = attr.ib(type=str, validator=type_validator())
@@ -231,6 +240,8 @@ class OriginVisit(BaseModel):
"""Represents a visit of an origin at a given point in time, by a
SWH loader."""
+ object_type: Final = "origin_visit"
+
origin = attr.ib(type=str, validator=type_validator())
date = attr.ib(type=datetime.datetime, validator=type_validator())
type = attr.ib(type=str, validator=type_validator())
@@ -258,6 +269,8 @@ class OriginVisitStatus(BaseModel):
"""
+ object_type: Final = "origin_visit_status"
+
origin = attr.ib(type=str, validator=type_validator())
visit = attr.ib(type=int, validator=type_validator())
@@ -298,6 +311,8 @@ class ObjectType(Enum):
class SnapshotBranch(BaseModel):
"""Represents one of the branches of a snapshot."""
+ object_type: Final = "snapshot_branch"
+
target = attr.ib(type=bytes, validator=type_validator())
target_type = attr.ib(type=TargetType, validator=type_validator())
@@ -318,6 +333,8 @@ class SnapshotBranch(BaseModel):
class Snapshot(BaseModel, HashableObject):
"""Represents the full state of an origin at a given point in time."""
+ object_type: Final = "snapshot"
+
branches = attr.ib(
type=Dict[bytes, Optional[SnapshotBranch]], validator=type_validator()
)
@@ -341,6 +358,8 @@ class Snapshot(BaseModel, HashableObject):
@attr.s(frozen=True)
class Release(BaseModel, HashableObject):
+ object_type: Final = "release"
+
name = attr.ib(type=bytes, validator=type_validator())
message = attr.ib(type=Optional[bytes], validator=type_validator())
target = attr.ib(type=Optional[Sha1Git], validator=type_validator())
@@ -399,6 +418,8 @@ class RevisionType(Enum):
@attr.s(frozen=True)
class Revision(BaseModel, HashableObject):
+ object_type: Final = "revision"
+
message = attr.ib(type=Optional[bytes], validator=type_validator())
author = attr.ib(type=Person, validator=type_validator())
committer = attr.ib(type=Person, validator=type_validator())
@@ -453,6 +474,8 @@ class Revision(BaseModel, HashableObject):
@attr.s(frozen=True)
class DirectoryEntry(BaseModel):
+ object_type: Final = "directory_entry"
+
name = attr.ib(type=bytes, validator=type_validator())
type = attr.ib(type=str, validator=attr.validators.in_(["file", "dir", "rev"]))
target = attr.ib(type=Sha1Git, validator=type_validator())
@@ -462,6 +485,8 @@ class DirectoryEntry(BaseModel):
@attr.s(frozen=True)
class Directory(BaseModel, HashableObject):
+ object_type: Final = "directory"
+
entries = attr.ib(type=Tuple[DirectoryEntry, ...], validator=type_validator())
id = attr.ib(type=Sha1Git, validator=type_validator(), default=b"")
@@ -518,6 +543,8 @@ class BaseContent(BaseModel):
@attr.s(frozen=True)
class Content(BaseContent):
+ object_type: Final = "content"
+
sha1 = attr.ib(type=bytes, validator=type_validator())
sha1_git = attr.ib(type=Sha1Git, validator=type_validator())
sha256 = attr.ib(type=bytes, validator=type_validator())
@@ -584,6 +611,8 @@ class Content(BaseContent):
@attr.s(frozen=True)
class SkippedContent(BaseContent):
+ object_type: Final = "skipped_content"
+
sha1 = attr.ib(type=Optional[bytes], validator=type_validator())
sha1_git = attr.ib(type=Optional[Sha1Git], validator=type_validator())
sha256 = attr.ib(type=Optional[bytes], validator=type_validator())
diff --git a/swh/model/tests/test_model.py b/swh/model/tests/test_model.py
index e126ca57..df949244 100644
--- a/swh/model/tests/test_model.py
+++ b/swh/model/tests/test_model.py
@@ -13,6 +13,7 @@ from hypothesis.strategies import binary
import pytest
from swh.model.model import (
+ BaseModel,
Content,
SkippedContent,
Directory,
@@ -468,3 +469,24 @@ def test_snapshot_model_id_computation():
snp_id = hash_to_bytes(snapshot_identifier(snp_dict))
snp_model = Snapshot.from_dict(snp_dict)
assert snp_model.id == snp_id
+
+
+@given(strategies.objects(split_content=True))
+def test_object_type(objtype_and_obj):
+ obj_type, obj = objtype_and_obj
+ assert obj_type == obj.object_type
+
+
+def test_object_type_is_final():
+ object_types = set()
+
+ def check_final(cls):
+ if hasattr(cls, "object_type"):
+ assert cls.object_type not in object_types
+ object_types.add(cls.object_type)
+ if cls.__subclasses__():
+ assert not hasattr(cls, "object_type")
+ for subcls in cls.__subclasses__():
+ check_final(subcls)
+
+ check_final(BaseModel)
--
GitLab