Small refactoring with minor improvements.

src/bsv/exception.py

@@ -0,0 +1,29 @@
+# bsv - Backup, Synchronization, Versioning
+# Copyright (C) 2023  Simon Boyé
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+from __future__ import annotations
+
+
+class BsvError(RuntimeError):
+    pass
+
+class NotFound(BsvError):
+    pass
+
+class UnexpectedObjectType(BsvError):
+    pass
+
+class ConfigError(BsvError):
+    pass

src/bsv/object.py

@@ -0,0 +1,41 @@
+# bsv - Backup, Synchronization, Versioning
+# Copyright (C) 2023  Simon Boyé
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+from __future__ import annotations
+
+from dataclasses import dataclass
+
+
+@dataclass(frozen=True, order=True, slots=True)
+class Digest:
+    digest: bytes
+
+    def __repr__(self) -> str:
+        return self.digest.hex()
+
+
+@dataclass(frozen=True, order=True, slots=True)
+class ObjectInfo:
+    digest: Digest
+    object_type: bytes
+    size: int
+
+    def __repr__(self) -> str:
+        return f"<{self.__class__.__name__} {self.digest} {self.object_type.decode()} {self.size}B>"
+
+
+@dataclass(frozen=True, order=True, slots=True)
+class Object(ObjectInfo):
+    data: bytes

src/bsv/repository.py

@@ -16,7 +16,7 @@
 from __future__ import annotations
 
 from dataclasses import dataclass
-from datetime import UTC, datetime as DateTime, timedelta as TimeDelta
+from datetime import datetime as DateTime
 import hashlib
 from io import BytesIO
 from pathlib import Path, PurePosixPath
@@ -28,9 +28,10 @@ from fastcdc import fastcdc
 import tomlkit
 
 from bsv import __version__
+from bsv.exception import ConfigError
 from bsv.simple_cas import SimpleCas
-from bsv.simple_cas.cas import ConfigError, Digest, SimpleCas
+from bsv.simple_cas.cas import Digest, SimpleCas
-from bsv.simple_cas.util import Hash, read_exact, read_exact_or_eof
+from bsv.util import Hash, read_exact, read_exact_or_eof, time_from_timestamp, timestamp_from_time
 
 
 DEFAULT_MIN_CHUNK_SIZE = 1 << 12
@@ -212,7 +213,9 @@ def make_cas(cas_name: str, path: Path, hash_factory: Callable[[], Hash]) -> Sim
     raise ConfigError(f"unknown cas name {cas_name}")
 
 
-@dataclass
+
+
+@dataclass(slots=True)
 class ChunkedObject:
     repo: Repository
     size: int
@@ -229,16 +232,41 @@ class ChunkedObject:
             self.chunks.append(chunk)
         return self
 
+    def reader(self) -> ChunkedObjectReader:
+        return ChunkedObjectReader(self)
 
-@dataclass
+
-class Blob(ChunkedObject):
+@dataclass(frozen=True, slots=True)
+class Chunk:
+    digest: Digest
+    size: int
+
+    @classmethod
+    def from_stream(cls, stream: BinaryIO, digest_size: int) -> Chunk | None:
+        digest_bytes = read_exact_or_eof(stream, digest_size)
+        if digest_bytes is None:
+            return None
+        digest = Digest(digest_bytes)
+
+        return cls(
+            digest = digest,
+            size = int.from_bytes(read_exact(stream, 4)),
+        )
+
+
+class ChunkedObjectReader:
+    _chunked_object: ChunkedObject
     _chunk_index: int = 0
     _chunk_data: bytes = b""
 
+    def __init__(self, chunked_object: ChunkedObject):
+        self._chunked_object = chunked_object
+
     def read(self, num_bytes: int = -1) -> bytes:
+        chunks = self._chunked_object.chunks
         parts = [self._chunk_data]
         size = len(parts[-1])
-        while (num_bytes < 0 or size < num_bytes) and self._chunk_index < len(self.chunks):
+        while (num_bytes < 0 or size < num_bytes) and self._chunk_index < len(chunks):
             parts.append(self.read1())
             size += len(parts[-1])
         if num_bytes >= 0:
@@ -248,13 +276,23 @@ class Blob(ChunkedObject):
         return b"".join(parts)
 
     def read1(self) -> bytes:
-        if self._chunk_index == len(self.chunks):
+        cas = self._chunked_object.repo._cas
+        chunks = self._chunked_object.chunks
+        if self._chunk_index == len(chunks):
             return b""
-        object = self.repo._cas.read(self.chunks[self._chunk_index].digest, object_type=b"chnk")
+        object = cas.read(chunks[self._chunk_index].digest, object_type=b"chnk")
         self._chunk_index += 1
         return object.data
 
 
+
+@dataclass(slots=True)
+class Blob(ChunkedObject):
+    pass
+
+
+
+
 @dataclass
 class Tree:
     repo: Repository
@@ -283,8 +321,6 @@ class Tree:
         return stream.getvalue()
 
 
-EPOCH = DateTime(1970, 1, 1, tzinfo=UTC)
-
 @dataclass
 class TreeItem:
     name: str
@@ -346,6 +382,8 @@ class TreeItem:
         stream.write(name_bytes)
 
 
+
+
 @dataclass
 class Snapshot:
     repo: Repository
@@ -387,22 +425,6 @@ class Snapshot:
         return stream.getvalue()
 
 
-@dataclass
-class Chunk:
-    digest: Digest
-    size: int
-
-    @classmethod
-    def from_stream(cls, stream: BinaryIO, digest_size: int) -> Chunk | None:
-        digest_bytes = read_exact_or_eof(stream, digest_size)
-        if digest_bytes is None:
-            return None
-        digest = Digest(digest_bytes)
-
-        return cls(
-            digest = digest,
-            size = int.from_bytes(read_exact(stream, 4)),
-        )
 
 
 class PathPair:
@@ -428,10 +450,3 @@ class PathPair:
 
     def __lt__(self, rhs: PathPair) -> bool:
         return self.bsv < rhs.bsv
-
-
-def time_from_timestamp(timestamp: int) -> DateTime:
-    return EPOCH + TimeDelta(microseconds=timestamp)
-
-def timestamp_from_time(time: DateTime) -> int:
-    return (time.astimezone(UTC) - EPOCH) // TimeDelta(microseconds=1)

src/bsv/simple_cas/cas.py

@@ -19,21 +19,10 @@ from dataclasses import dataclass
 import hashlib
 from pathlib import Path
 from typing import Any, BinaryIO, Callable, Iterator
+from bsv.exception import NotFound, UnexpectedObjectType
+from bsv.object import Digest, Object, ObjectInfo
 
-from bsv.simple_cas.util import Hash, read_exact_or_eof
+from bsv.util import Hash, read_exact_or_eof
-
-
-class BsvError(RuntimeError):
-    pass
-
-class NotFound(BsvError):
-    pass
-
-class UnexpectedObjectType(BsvError):
-    pass
-
-class ConfigError(BsvError):
-    pass
 
 
 class SimpleCas:
@@ -105,7 +94,7 @@ class SimpleCas:
             assert size == item.size
             data = stream.read(size)
 
-        return Object(object_type, data)
+        return Object(digest, object_type, size, data)
 
     def write(self, object_type: bytes, data: bytes) -> Digest:
         assert len(object_type) == 4
@@ -164,22 +153,6 @@ class SimpleCas:
         return self._root_dir / "refs" / key_path
 
 
-@dataclass(frozen=True, order=True, slots=True)
-class Digest:
-    digest: bytes
-
-    def __repr__(self) -> str:
-        return self.digest.hex()
-
-
-@dataclass
-class Object:
-    object_type: bytes
-    data: bytes
-
-    def __repr__(self) -> str:
-        return f"<Object {self.object_type.decode()}: {len(self.data)}B>"
-
 @dataclass
 class IndexItem:
     object_type: bytes
@@ -188,12 +161,3 @@ class IndexItem:
 
     def __repr__(self) -> str:
         return f"<IndexItem {self.object_type.decode()}: {self.offset}B +{self.size}B>"
-
-@dataclass
-class ObjectInfo:
-    digest: Digest
-    object_type: bytes
-    size: int
-
-    def __repr__(self) -> str:
-        return f"<ObjectInfo {self.digest} {self.object_type.decode()} {self.size}B>"

src/bsv/util.py

@@ -16,9 +16,20 @@
 from __future__ import annotations
 
 from abc import ABC, abstractmethod
+from datetime import UTC, datetime as DateTime, timedelta as TimeDelta
 from typing import BinaryIO
 
 
+EPOCH = DateTime(1970, 1, 1, tzinfo=UTC)
+
+
+def time_from_timestamp(timestamp: int) -> DateTime:
+    return EPOCH + TimeDelta(microseconds=timestamp)
+
+def timestamp_from_time(time: DateTime) -> int:
+    return (time.astimezone(UTC) - EPOCH) // TimeDelta(microseconds=1)
+
+
 def read_exact(stream: BinaryIO, num_bytes: int) -> bytes:
     data = stream.read(num_bytes)
     if len(data) != num_bytes:

tests/test_repository.py

@@ -49,7 +49,7 @@ def test_read_write_blob(tmp_dir: Path, repo: Repository):
         digest = repo.add_blob(stream)
 
     blob = repo.get_blob(digest)
-    data = blob.read()
+    data = blob.reader().read()
 
     with path.open("rb") as stream:
         assert data == stream.read()

tests/test_simple_cas.py

@@ -55,7 +55,9 @@ def test_simple_cas(tmp_dir: Path):
 
         obj = cas.read(digest)
         assert obj is not None
+        assert obj.digest == digest
         assert obj.object_type == b"blob"
+        assert obj.size == len(data)
         assert obj.data == data
 
     cas = SimpleCas(
@@ -68,7 +70,9 @@ def test_simple_cas(tmp_dir: Path):
 
         obj = cas.read(digest)
         assert obj is not None
+        assert obj.digest == digest
         assert obj.object_type == b"blob"
+        assert obj.size == len(data)
         assert obj.data == data
 
         digest2 = cas.write(b"blob", data)