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nanobot/nanobot/agent/tools/file_state.py
T

120 lines
3.5 KiB
Python

"""Track file-read state for read-before-edit warnings and read deduplication."""
from __future__ import annotations
import hashlib
import os
from dataclasses import dataclass
from pathlib import Path
@dataclass(slots=True)
class ReadState:
mtime: float
offset: int
limit: int | None
content_hash: str | None
can_dedup: bool
_state: dict[str, ReadState] = {}
def _hash_file(p: str) -> str | None:
try:
return hashlib.sha256(Path(p).read_bytes()).hexdigest()
except OSError:
return None
def record_read(path: str | Path, offset: int = 1, limit: int | None = None) -> None:
"""Record that a file was read (called after successful read)."""
p = str(Path(path).resolve())
try:
mtime = os.path.getmtime(p)
except OSError:
return
_state[p] = ReadState(
mtime=mtime,
offset=offset,
limit=limit,
content_hash=_hash_file(p),
can_dedup=True,
)
def record_write(path: str | Path) -> None:
"""Record that a file was written (updates mtime in state)."""
p = str(Path(path).resolve())
try:
mtime = os.path.getmtime(p)
except OSError:
_state.pop(p, None)
return
_state[p] = ReadState(
mtime=mtime,
offset=1,
limit=None,
content_hash=_hash_file(p),
can_dedup=False,
)
def check_read(path: str | Path) -> str | None:
"""Check if a file has been read and is fresh.
Returns None if OK, or a warning string.
When mtime changed but file content is identical (e.g. touch, editor save),
the check passes to avoid false-positive staleness warnings.
"""
p = str(Path(path).resolve())
entry = _state.get(p)
if entry is None:
return "Warning: file has not been read yet. Read it first to verify content before editing."
try:
current_mtime = os.path.getmtime(p)
except OSError:
return None
if current_mtime != entry.mtime:
if entry.content_hash and _hash_file(p) == entry.content_hash:
entry.mtime = current_mtime
return None
return "Warning: file has been modified since last read. Re-read to verify content before editing."
# mtime unchanged - still check content hash to detect quick modifications
if entry.content_hash and _hash_file(p) != entry.content_hash:
return "Warning: file has been modified since last read. Re-read to verify content before editing."
return None
def is_unchanged(path: str | Path, offset: int = 1, limit: int | None = None) -> bool:
"""Return True if file was previously read with same params and content is unchanged."""
p = str(Path(path).resolve())
entry = _state.get(p)
if entry is None:
return False
if not entry.can_dedup:
return False
if entry.offset != offset or entry.limit != limit:
return False
try:
current_mtime = os.path.getmtime(p)
except OSError:
return False
if current_mtime != entry.mtime:
# mtime changed - check if content also changed
current_hash = _hash_file(p)
if current_hash != entry.content_hash:
# Content actually changed - don't dedup
entry.can_dedup = False
return False
# Content identical despite mtime change (e.g. touch) - mark as not dedupable to force full read next time
entry.can_dedup = False
return True
# mtime unchanged - content must be identical
return True
def clear() -> None:
"""Clear all tracked state (useful for testing)."""
_state.clear()