516 lines
21 KiB
Python
516 lines
21 KiB
Python
"""Conversation-scoped shallow file versioning for workspace edits.
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Mirrors Claude Code's file-history approach:
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- Only files touched by write_file / edit_file are tracked.
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- Before each edit the current content is backed up.
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- A snapshot is taken per user message, referencing the latest backup version
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of every tracked file at that point in time.
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- Rewind restores the tracked files to the state recorded for a target message.
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"""
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from __future__ import annotations
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import hashlib
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import json
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import shutil
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from dataclasses import dataclass, field
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from datetime import datetime
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from pathlib import Path
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from typing import Any, Dict, List, Optional, Set
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class ShallowVersioningError(RuntimeError):
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"""Raised when shallow versioning fails."""
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@dataclass
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class FileBackup:
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backup_file_name: Optional[str] # null means the file did not exist at that version
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version: int
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backup_time: str
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@dataclass
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class ShallowSnapshot:
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message_id: str
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tracked_file_backups: Dict[str, FileBackup]
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timestamp: str
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class ShallowVersioningManager:
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"""Lightweight per-conversation backup for files edited by AI tools."""
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MAX_SNAPSHOTS = 100
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def __init__(self, project_path: Path | str, data_dir: Path | str, conversation_id: str):
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self.project_path = Path(project_path).expanduser().resolve()
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self.conversation_id = str(conversation_id or "").strip()
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if not self.conversation_id:
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raise ShallowVersioningError("缺少 conversation_id")
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self.save_root = (Path(data_dir).expanduser().resolve() / "save" / self.conversation_id).resolve()
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self.backup_dir = self.save_root / "shallow_backups"
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self.state_file = self.backup_dir / "state.jsonl"
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self._tracked_files: Set[str] = set()
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self._snapshots: List[ShallowSnapshot] = []
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self._snapshot_sequence = 0
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self._load_state()
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# ----------------------------
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# persistence
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# ----------------------------
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def _load_state(self) -> None:
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if not self.state_file.exists():
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return
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try:
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for raw in self.state_file.read_text(encoding="utf-8", errors="ignore").splitlines():
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line = raw.strip()
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if not line:
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continue
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try:
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row = json.loads(line)
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except Exception:
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continue
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if not isinstance(row, dict):
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continue
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snapshot = self._deserialize_snapshot(row)
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if snapshot:
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self._snapshots.append(snapshot)
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self._snapshot_sequence += 1
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for path in snapshot.tracked_file_backups:
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self._tracked_files.add(path)
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except OSError:
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pass
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def _persist_snapshot(self, snapshot: ShallowSnapshot) -> None:
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self.backup_dir.mkdir(parents=True, exist_ok=True)
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with self.state_file.open("a", encoding="utf-8") as fh:
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fh.write(json.dumps(self._serialize_snapshot(snapshot), ensure_ascii=False) + "\n")
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def _serialize_snapshot(self, snapshot: ShallowSnapshot) -> Dict[str, Any]:
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return {
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"message_id": snapshot.message_id,
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"timestamp": snapshot.timestamp,
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"tracked_file_backups": {
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path: {
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"backup_file_name": backup.backup_file_name,
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"version": backup.version,
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"backup_time": backup.backup_time,
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}
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for path, backup in snapshot.tracked_file_backups.items()
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},
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}
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def _deserialize_snapshot(self, row: Dict[str, Any]) -> Optional[ShallowSnapshot]:
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if not isinstance(row.get("message_id"), str):
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return None
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backups: Dict[str, FileBackup] = {}
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for path, backup_raw in (row.get("tracked_file_backups") or {}).items():
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if not isinstance(backup_raw, dict):
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continue
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backups[str(path)] = FileBackup(
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backup_file_name=backup_raw.get("backup_file_name"),
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version=int(backup_raw.get("version") or 1),
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backup_time=str(backup_raw.get("backup_time") or datetime.now().isoformat()),
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)
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return ShallowSnapshot(
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message_id=row["message_id"],
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tracked_file_backups=backups,
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timestamp=str(row.get("timestamp") or datetime.now().isoformat()),
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)
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# ----------------------------
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# path helpers
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# ----------------------------
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def _normalize_path(self, file_path: Path | str) -> str:
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path = Path(file_path).expanduser()
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if not path.is_absolute():
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path = self.project_path / path
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try:
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rel = path.resolve().relative_to(self.project_path)
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return str(rel).replace("\\", "/")
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except ValueError:
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return str(path).replace("\\", "/")
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def _resolve_file_path(self, tracking_path: str) -> Path:
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if Path(tracking_path).is_absolute():
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return Path(tracking_path).expanduser().resolve()
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return (self.project_path / tracking_path).resolve()
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def _backup_file_name(self, tracking_path: str, version: int) -> str:
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file_name_hash = hashlib.sha256(tracking_path.encode("utf-8")).hexdigest()[:16]
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return f"{file_name_hash}@v{version}"
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def _backup_path(self, backup_file_name: str) -> Path:
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return (self.backup_dir / backup_file_name).resolve()
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# ----------------------------
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# backup operations
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# ----------------------------
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def _create_backup(self, file_path: Path, version: int) -> FileBackup:
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backup_file_name = self._backup_file_name(str(file_path), version)
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backup_path = self._backup_path(backup_file_name)
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backup_path.parent.mkdir(parents=True, exist_ok=True)
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if not file_path.exists():
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return FileBackup(backup_file_name=None, version=version, backup_time=datetime.now().isoformat())
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shutil.copy2(file_path, backup_path)
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return FileBackup(
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backup_file_name=backup_file_name,
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version=version,
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backup_time=datetime.now().isoformat(),
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)
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def _get_latest_backup_version(self, tracking_path: str) -> Optional[FileBackup]:
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latest: Optional[FileBackup] = None
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for snapshot in self._snapshots:
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backup = snapshot.tracked_file_backups.get(tracking_path)
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if backup and (latest is None or backup.version > latest.version):
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latest = backup
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return latest
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def _file_changed_since_backup(self, file_path: Path, backup: FileBackup) -> bool:
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if backup.backup_file_name is None:
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return file_path.exists()
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backup_path = self._backup_path(backup.backup_file_name)
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if not file_path.exists():
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return True
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if not backup_path.exists():
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return True
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try:
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if file_path.stat().st_size != backup_path.stat().st_size:
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return True
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current = file_path.read_text(encoding="utf-8", errors="ignore")
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saved = backup_path.read_text(encoding="utf-8", errors="ignore")
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return current != saved
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except Exception:
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return True
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# ----------------------------
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# public API
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# ----------------------------
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def _find_latest_snapshot_by_message_id(self, message_id: str) -> Optional[ShallowSnapshot]:
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"""Return the most recent snapshot whose message_id matches."""
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target = str(message_id or "")
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for snapshot in reversed(self._snapshots):
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if str(snapshot.message_id or "") == target:
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return snapshot
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return None
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def track_edit(self, file_path: Path | str, message_id: str) -> None:
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"""Track a file before it is edited; backup its current content if not already tracked."""
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tracking_path = self._normalize_path(file_path)
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from utils.perf_log import perf_log
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perf_log("[ShallowVersioning] track_edit called", extra={
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"tracking_path": tracking_path,
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"message_id": message_id,
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"already_tracked": tracking_path in self._tracked_files,
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"snapshots_count": len(self._snapshots),
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})
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if tracking_path in self._tracked_files:
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return
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resolved = self._resolve_file_path(tracking_path)
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backup = self._create_backup(resolved, 1)
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self._tracked_files.add(tracking_path)
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# 归属到当前 message_id 对应的最新 snapshot；不存在则新建。
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# 避免把本次输入的修改追加到上一个输入的 snapshot。
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now = datetime.now().isoformat()
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target_snapshot = self._find_latest_snapshot_by_message_id(message_id)
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if target_snapshot is not None:
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target_snapshot.tracked_file_backups[tracking_path] = backup
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self._persist_snapshot(target_snapshot)
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else:
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snapshot = ShallowSnapshot(
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message_id=message_id,
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tracked_file_backups={tracking_path: backup},
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timestamp=now,
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)
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self._snapshots.append(snapshot)
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self._snapshot_sequence += 1
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self._persist_snapshot(snapshot)
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def make_snapshot(self, message_id: str) -> Dict[str, Any]:
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"""Create a snapshot for the given message, backing up changed tracked files."""
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from utils.perf_log import perf_log
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perf_log("[ShallowVersioning] make_snapshot called", extra={
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"message_id": message_id,
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"tracked_files_count": len(self._tracked_files),
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"snapshots_count": len(self._snapshots),
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})
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tracked_file_backups: Dict[str, FileBackup] = {}
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now = datetime.now().isoformat()
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for tracking_path in self._tracked_files:
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resolved = self._resolve_file_path(tracking_path)
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latest_backup = self._get_latest_backup_version(tracking_path)
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next_version = (latest_backup.version + 1) if latest_backup else 1
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if latest_backup and not self._file_changed_since_backup(resolved, latest_backup):
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tracked_file_backups[tracking_path] = latest_backup
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continue
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tracked_file_backups[tracking_path] = self._create_backup(resolved, next_version)
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# Merge in backups from the latest snapshot for any files that may have been added
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# by track_edit during the async window.
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if self._snapshots:
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for tracking_path, backup in self._snapshots[-1].tracked_file_backups.items():
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if tracking_path not in tracked_file_backups:
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tracked_file_backups[tracking_path] = backup
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snapshot = ShallowSnapshot(
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message_id=message_id,
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tracked_file_backups=tracked_file_backups,
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timestamp=now,
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)
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# 如果当前 message_id 已存在 snapshot（由 track_edit 预创建），则替换它，
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# 避免同一个输入节点留下多个 snapshot 导致 diff 只计算最后两次之间的变化。
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existing_index = -1
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for idx, s in enumerate(self._snapshots):
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if str(s.message_id or "") == str(message_id or ""):
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existing_index = idx
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if existing_index >= 0:
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self._snapshots[existing_index] = snapshot
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else:
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self._snapshots.append(snapshot)
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self._snapshot_sequence += 1
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self._persist_snapshot(snapshot)
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# Evict old snapshots while keeping the most recent MAX_SNAPSHOTS.
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if len(self._snapshots) > self.MAX_SNAPSHOTS:
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self._snapshots = self._snapshots[-self.MAX_SNAPSHOTS :]
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perf_log("[ShallowVersioning] make_snapshot done", extra={
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"message_id": message_id,
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"tracked_files_count": len(tracked_file_backups),
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"backups": {k: v.backup_file_name for k, v in tracked_file_backups.items()},
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})
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return {
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"message_id": message_id,
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"tracked_files_count": len(tracked_file_backups),
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"timestamp": now,
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}
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def can_restore(self, message_id: str) -> bool:
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return any(snapshot.message_id == message_id for snapshot in self._snapshots)
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def rewind(self, message_id: str) -> Dict[str, Any]:
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"""Restore tracked files to the state recorded for the target message."""
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target_snapshot: Optional[ShallowSnapshot] = None
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for snapshot in reversed(self._snapshots):
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if snapshot.message_id == message_id:
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target_snapshot = snapshot
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break
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if not target_snapshot:
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raise ShallowVersioningError(f"未找到消息 {message_id} 对应的快照")
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files_changed: List[str] = []
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for tracking_path in self._tracked_files:
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target_backup = target_snapshot.tracked_file_backups.get(tracking_path)
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if not target_backup:
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# File was not tracked at the target snapshot; leave it unchanged.
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continue
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resolved = self._resolve_file_path(tracking_path)
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if target_backup.backup_file_name is None:
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if resolved.exists():
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resolved.unlink()
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files_changed.append(tracking_path)
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continue
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backup_path = self._backup_path(target_backup.backup_file_name)
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if not backup_path.exists():
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continue
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if self._file_changed_since_backup(resolved, target_backup):
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resolved.parent.mkdir(parents=True, exist_ok=True)
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shutil.copy2(backup_path, resolved)
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files_changed.append(tracking_path)
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return {
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"success": True,
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"message_id": message_id,
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"files_changed": files_changed,
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}
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def _read_backup_lines(self, backup: Optional[FileBackup]) -> List[str]:
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"""Read lines from a backup entry; empty list for missing/deleted files."""
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if not backup or backup.backup_file_name is None:
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return []
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backup_path = self._backup_path(backup.backup_file_name)
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if not backup_path.exists():
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return []
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try:
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return backup_path.read_text(encoding="utf-8", errors="ignore").splitlines()
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except Exception:
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return []
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def _count_line_changes(self, previous_lines: List[str], target_lines: List[str]) -> tuple[int, int]:
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"""Count real insertions/deletions between two line lists using SequenceMatcher."""
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if previous_lines == target_lines:
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return 0, 0
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try:
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import difflib
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sm = difflib.SequenceMatcher(None, previous_lines, target_lines)
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except Exception:
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# Fallback to naive delta if difflib fails.
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if len(previous_lines) > len(target_lines):
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return 0, len(previous_lines) - len(target_lines)
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return len(target_lines) - len(previous_lines), 0
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insertions = 0
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deletions = 0
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for tag, i1, i2, j1, j2 in sm.get_opcodes():
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if tag == "insert":
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insertions += j2 - j1
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elif tag == "delete":
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deletions += i2 - i1
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elif tag == "replace":
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insertions += j2 - j1
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deletions += i2 - i1
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return insertions, deletions
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def _find_snapshot_pair(self, message_id: str):
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"""Return (target_snapshot, previous_snapshot) for the given message_id."""
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target_snapshot: Optional[ShallowSnapshot] = None
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target_index = -1
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for idx, snapshot in enumerate(self._snapshots):
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if snapshot.message_id == message_id:
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target_snapshot = snapshot
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target_index = idx
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if not target_snapshot or target_index < 0:
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return None, None
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previous_snapshot = self._snapshots[target_index - 1] if target_index > 0 else None
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return target_snapshot, previous_snapshot
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def get_diff_stats(self, message_id: str) -> Optional[Dict[str, Any]]:
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"""Compute insertions/deletions/files_changed between the target snapshot and the previous snapshot."""
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target_snapshot, previous_snapshot = self._find_snapshot_pair(message_id)
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if not target_snapshot:
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return None
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files_changed: List[str] = []
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insertions = 0
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deletions = 0
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for tracking_path in self._tracked_files:
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target_backup = target_snapshot.tracked_file_backups.get(tracking_path)
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if not target_backup:
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continue
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previous_backup = previous_snapshot.tracked_file_backups.get(tracking_path) if previous_snapshot else None
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previous_lines = self._read_backup_lines(previous_backup)
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target_lines = self._read_backup_lines(target_backup)
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if previous_lines == target_lines:
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continue
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files_changed.append(tracking_path)
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ins, dels = self._count_line_changes(previous_lines, target_lines)
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insertions += ins
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deletions += dels
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return {
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"filesChanged": files_changed,
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"insertions": insertions,
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"deletions": deletions,
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}
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def has_any_changes(self, message_id: str) -> bool:
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stats = self.get_diff_stats(message_id)
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if not stats:
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return False
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return bool(stats.get("filesChanged"))
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def get_file_diff_stats(self, message_id: str) -> List[Dict[str, Any]]:
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"""Return per-file insertions/deletions/status for a target snapshot vs previous snapshot."""
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target_snapshot, previous_snapshot = self._find_snapshot_pair(message_id)
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if not target_snapshot:
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return []
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result: List[Dict[str, Any]] = []
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for tracking_path in self._tracked_files:
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target_backup = target_snapshot.tracked_file_backups.get(tracking_path)
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if not target_backup:
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continue
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previous_backup = previous_snapshot.tracked_file_backups.get(tracking_path) if previous_snapshot else None
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previous_lines = self._read_backup_lines(previous_backup)
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target_lines = self._read_backup_lines(target_backup)
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if previous_lines == target_lines:
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continue
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insertions, deletions = self._count_line_changes(previous_lines, target_lines)
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resolved = self._resolve_file_path(tracking_path)
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status = "deleted" if target_backup.backup_file_name is None else ("added" if previous_backup is None or previous_backup.backup_file_name is None else "modified")
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result.append({
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"path": tracking_path,
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"status": status,
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"insertions": insertions,
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"deletions": deletions,
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})
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return result
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def get_file_patch_lines(
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self,
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tracking_path: str,
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message_id: str,
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max_lines: int = 600,
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) -> Dict[str, Any]:
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"""Return contextual patch lines between target snapshot and previous snapshot."""
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target_snapshot, previous_snapshot = self._find_snapshot_pair(message_id)
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if not target_snapshot:
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return {"lines": [], "truncated": False}
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target_backup = target_snapshot.tracked_file_backups.get(tracking_path)
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if not target_backup:
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return {"lines": [], "truncated": False}
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previous_backup = previous_snapshot.tracked_file_backups.get(tracking_path) if previous_snapshot else None
|
||
previous_lines = self._read_backup_lines(previous_backup)
|
||
target_lines = self._read_backup_lines(target_backup)
|
||
|
||
if previous_lines == target_lines:
|
||
return {"lines": [], "truncated": False}
|
||
|
||
try:
|
||
import difflib
|
||
sm = difflib.SequenceMatcher(None, previous_lines, target_lines)
|
||
except Exception:
|
||
return {"lines": [], "truncated": False}
|
||
|
||
lines: List[Dict[str, Any]] = []
|
||
truncated = False
|
||
for tag, i1, i2, j1, j2 in sm.get_opcodes():
|
||
if tag == "equal":
|
||
continue
|
||
if tag == "replace" or tag == "delete":
|
||
for line in previous_lines[i1:i2]:
|
||
if len(lines) >= max_lines:
|
||
truncated = True
|
||
break
|
||
lines.append({"type": "remove", "content": line})
|
||
if tag == "replace" or tag == "insert":
|
||
for line in target_lines[j1:j2]:
|
||
if len(lines) >= max_lines:
|
||
truncated = True
|
||
break
|
||
lines.append({"type": "add", "content": line})
|
||
if truncated:
|
||
break
|
||
return {"lines": lines, "truncated": truncated}
|
||
|
||
def get_snapshot_by_seq(self, seq: int) -> Optional[ShallowSnapshot]:
|
||
"""Return the user-message snapshot by 1-based index (skips the initial track_edit snapshot)."""
|
||
user_snapshots = [s for s in self._snapshots if s.message_id != self.conversation_id]
|
||
idx = int(seq) - 1
|
||
if idx < 0 or idx >= len(user_snapshots):
|
||
return None
|
||
return user_snapshots[idx]
|
||
|
||
def list_snapshots(self) -> List[Dict[str, Any]]:
|
||
return [self._serialize_snapshot(s) for s in self._snapshots]
|