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https://github.com/kuhyx/utils.git
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Krzysztof kuhy Rudnicki
5be99ab11d
crdt_sync_dart: new domain-agnostic LogStore -- an in-memory Log with a reactive changes stream and upsert/delete(sticky tombstone)/replaceAll, behind an injectable LogPersistence port -- plus logToJson/logFromJson. FileLogPersistence (atomic temp-file-then-rename, generalizing diet_guard's LogStorageService) lives behind a separate crdt_sync_io.dart entrypoint so the core barrel stays pure Dart / web-safe. crdt-sync (Python): mirror dump_log/load_log/read_log/write_log sharing the same on-disk JSON format so a log written on one side parses on the other. Load/save only -- the reactive store is a Dart/Flutter convenience with no Python equivalent by design (Python consumers are headless sync ticks). Querying stays app-side: a Record's fields are opaque to the library, so filtering/sorting/search is the caller's job over LogStore.values. Both packages bumped to 0.2.0. 83 Dart tests + 71 Python tests (100% branch coverage) green. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_019KwUCPESvE5CjCtmUFz8xQ
71 lines
2.4 KiB
Python
71 lines
2.4 KiB
Python
"""Local JSON persistence for a ``Log``.
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Mirrors ``crdt_sync_dart``'s ``logToJson``/``FileLogPersistence`` serialization
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so a log written by the Dart side parses here and vice versa. Deliberately
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*non-reactive*: the change-stream/reactive store is a Dart/Flutter-only
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convenience (it exists to drive a live UI). On the Python side, where consumers
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are headless sync ticks, this is plain load and (atomic) save.
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"""
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from __future__ import annotations
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import json
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import os
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from typing import TYPE_CHECKING
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from crdt_sync._record import Record
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if TYPE_CHECKING:
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from pathlib import Path
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from crdt_sync._log import Log
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def dump_log(log: Log) -> str:
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"""Serialize ``log`` to canonical JSON text (id -> record dict)."""
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return json.dumps({rid: record.to_dict() for rid, record in log.items()})
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def load_log(text: str) -> Log:
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"""Parse text produced by :func:`dump_log` back into a ``Log``.
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Raises ``ValueError`` (bad JSON), ``KeyError`` or ``TypeError`` (valid
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JSON, wrong shape) on a corrupt payload -- callers reading from disk go
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through :func:`read_log`, which turns those into an empty log.
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"""
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raw = json.loads(text)
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if not isinstance(raw, dict):
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msg = f"expected a JSON object mapping id -> record, got {type(raw).__name__}"
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raise TypeError(msg)
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return {rid: Record.from_dict(value) for rid, value in raw.items()}
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def read_log(path: Path) -> Log:
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"""Read a ``Log`` from ``path``; empty on a missing or unparsable file.
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A truncated or corrupt file can never raise here: it is treated as "no log
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yet", matching the Dart store's defensive load so a half-written file can't
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brick a consumer.
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"""
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try:
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text = path.read_text(encoding="utf-8")
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except FileNotFoundError:
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return {}
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try:
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return load_log(text)
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except (ValueError, KeyError, TypeError):
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return {}
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def write_log(path: Path, log: Log) -> None:
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"""Write ``log`` to ``path`` atomically (temp file then rename).
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Writes to a per-process temp file and ``replace``s it over the real path,
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so a concurrent reader never observes a half-written file. Mirrors the
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Dart ``FileLogPersistence`` write scheme.
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"""
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path.parent.mkdir(parents=True, exist_ok=True)
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tmp = path.with_name(f"{path.name}.{os.getpid()}.tmp")
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tmp.write_text(dump_log(log), encoding="utf-8")
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tmp.replace(path)
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