Vito Sansevero
b9636ce88c
Python 3.12+ on Windows reports the change time from stat but the creation time from fstat, so a freshly written file whose creation and write straddle a clock tick failed the pre-read identity check with CaptureChanged. The path-versus-descriptor checks now compare size, mtime_ns and dev/ino; ctime_ns is compared between the fstat before and after the copy, where it still detects a same-size rewrite with a restored mtime on POSIX. The symlinked-root test asserted the locator against the unresolved temp path, which macOS (/var -> /private/var) and Windows (short names) resolve differently; it now compares against the real path.
570 lines
20 KiB
Python
570 lines
20 KiB
Python
"""Bounded private capture store for image annotations (#249 A3).
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One explicit Tag or review action captures exactly one selected media file:
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the rooted file is streamed to a private, owner-only temporary copy while its
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whole-file SHA-256 is computed, and the identity of the opened descriptor is
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checked against the path before and after the copy. Preview, inference and the
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metadata read use only that copy, so what the user reviewed is what the model
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saw and what Save re-checks. Everything is bounded: bytes per file, completed
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captures, reserved bytes, concurrent capture/verify workers, idle and hard
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lifetimes.
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The contract is "these bytes at this location, last checked at this time".
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Stat equality is never content proof: a same-size rewrite that restores
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``mtime_ns`` is visible only through the POSIX change time, which Windows does
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not expose through ``stat``.
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"""
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from __future__ import annotations
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import hashlib
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import logging
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import os
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import secrets
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import stat as stat_module
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import tempfile
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import threading
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import time
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import warnings
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from dataclasses import dataclass
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from pathlib import Path
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from typing import Callable
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from PIL import Image
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try:
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from .prompt_inspector import MetadataReadError, read_inspection_file
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from .video_metadata import VIDEO_EXTENSIONS, is_video_path
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except ImportError: # imported with the repo root on sys.path
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from utils.prompt_inspector import MetadataReadError, read_inspection_file
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from utils.video_metadata import VIDEO_EXTENSIONS, is_video_path
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logger = logging.getLogger(__name__)
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CHUNK_SIZE = 1024 * 1024
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DEFAULT_MAX_FILE = 256 * 2**20
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DEFAULT_MAX_CAPTURES = 8
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DEFAULT_MAX_BYTES = 512 * 2**20
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DEFAULT_MAX_WORKERS = 2
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DEFAULT_IDLE_SECONDS = 900
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DEFAULT_HARD_SECONDS = 1800
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MAX_INFERENCE_SIDE = 4096
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MAX_INFERENCE_PIXELS = 16_777_216
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MAX_RELATIVE_LENGTH = 1024
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VIDEO_ONLY_REASON = "Auto-tagging is available for supported still images only."
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HEADER_REASON = "The image header could not be read."
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DIMENSION_REASON = (
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"Images larger than 4096 px per side or 16,777,216 px are not supported."
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)
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# The listing's media allowlist (``py.api.inspection_service.SERVABLE_EXTENSIONS``),
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# restated here so utilities never import the aiohttp API package; a test pins
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# the two sets equal.
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_STILL_EXTENSIONS = frozenset(
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{".png", ".jpg", ".jpeg", ".webp", ".gif", ".bmp", ".tiff", ".tif"}
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)
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CAPTURE_EXTENSIONS = _STILL_EXTENSIONS | frozenset(VIDEO_EXTENSIONS)
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_DIRECTORY_PREFIX = "prompt-manager-captures-"
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_OPEN_FLAGS = (
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os.O_RDONLY
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| getattr(os, "O_BINARY", 0)
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| getattr(os, "O_NOFOLLOW", 0)
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| getattr(os, "O_CLOEXEC", 0)
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)
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class CaptureError(Exception):
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"""Base of the capture outcomes; ``code`` is the API error code."""
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code = "capture-error"
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class CaptureCapacity(CaptureError):
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"""Count, byte or worker admission failed (nonblocking)."""
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code = "review-capacity"
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class CaptureTooLarge(CaptureError):
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"""The file exceeds the per-file byte cap on stat or on the stream."""
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code = "unsupported-media"
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class CaptureChanged(CaptureError):
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"""The file changed, vanished or was replaced across the copy (retryable)."""
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code = "file-changed"
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class CaptureDenied(CaptureError):
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"""The target is not a listed rooted media file (alias, escape, non-media)."""
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code = "source-changed"
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@dataclass(frozen=True)
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class FileFacts:
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"""Whole-file facts of the current rooted file, without a retained copy."""
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locator: str
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sha256: str
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size: int
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mtime_ns: int
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@dataclass(frozen=True)
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class Capture:
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"""One completed private copy; ``path`` is the owner-only temporary file."""
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token: str
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locator: str
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root_index: int
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scope: str
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epoch: str
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sha256: str
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size: int
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mtime_ns: int
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path: str
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media_type: str
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width: int | None
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height: int | None
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inferable: bool
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inferable_reason: str | None
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class _Entry:
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__slots__ = ("capture", "created_at", "last_used_at", "uses", "doomed")
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def __init__(self, capture: Capture, now: float):
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self.capture = capture
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self.created_at = now
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self.last_used_at = now
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self.uses = 0
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self.doomed = False
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def _same_file(
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before: os.stat_result, after: os.stat_result, *, change_time: bool
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) -> bool:
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"""Size and mtime must agree, device/inode where meaningful.
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The change time is compared only between two reads of the same kind
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(``fstat`` before and after the copy): Windows reports the creation time
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from ``fstat`` but, on Python 3.12+, the change time from ``stat``.
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"""
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if before.st_size != after.st_size or before.st_mtime_ns != after.st_mtime_ns:
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return False
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if change_time and before.st_ctime_ns != after.st_ctime_ns:
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return False
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if before.st_ino and after.st_ino and before.st_ino != after.st_ino:
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return False
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if before.st_dev and after.st_dev and before.st_dev != after.st_dev:
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return False
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return True
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def _unlink_quietly(path: str) -> None:
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try:
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os.unlink(path)
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except FileNotFoundError:
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pass
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except OSError as error:
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logger.warning("Capture file %s could not be removed: %s", path, error)
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class CaptureStore:
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"""Bounded, lock-protected registry of private media captures."""
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def __init__(
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self,
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temp_parent: os.PathLike | str | None = None,
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*,
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max_file: int = DEFAULT_MAX_FILE,
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max_captures: int = DEFAULT_MAX_CAPTURES,
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max_bytes: int = DEFAULT_MAX_BYTES,
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max_workers: int = DEFAULT_MAX_WORKERS,
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idle: float = DEFAULT_IDLE_SECONDS,
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hard: float = DEFAULT_HARD_SECONDS,
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clock: Callable[[], float] = time.monotonic,
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):
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for name, value in (
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("max_file", max_file),
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("max_captures", max_captures),
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("max_bytes", max_bytes),
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("max_workers", max_workers),
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):
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if isinstance(value, bool) or not isinstance(value, int) or value < 1:
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raise ValueError(f"{name} must be a positive integer")
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if not (idle > 0 and hard > 0):
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raise ValueError("idle and hard must be positive")
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self.max_file = max_file
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self.max_captures = max_captures
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self.max_bytes = max_bytes
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self.max_workers = max_workers
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self.idle = idle
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self.hard = hard
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self._clock = clock
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parent = None if temp_parent is None else os.fspath(temp_parent)
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if parent is not None:
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os.makedirs(parent, exist_ok=True)
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# mkdtemp creates the directory with owner-only permissions.
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self.directory = tempfile.mkdtemp(prefix=_DIRECTORY_PREFIX, dir=parent)
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self._lock = threading.Lock()
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self._entries: dict[str, _Entry] = {}
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self._completed_bytes = 0
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self._pending = 0
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self._pending_bytes = 0
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self._workers = 0
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self._closed = False
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# -- public API ------------------------------------------------------------
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def capture(
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self,
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root: os.PathLike | str,
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relative: str,
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*,
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epoch: str,
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scope: str,
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root_index: int = 0,
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) -> Capture:
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"""Copy and hash one rooted media file into a private capture."""
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if isinstance(root_index, bool) or not isinstance(root_index, int):
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raise CaptureDenied("Invalid gallery root")
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if root_index < 0:
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raise CaptureDenied("Invalid gallery root")
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for name, value in (("epoch", epoch), ("scope", scope)):
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if not isinstance(value, str) or not value:
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raise ValueError(f"{name} must be a non-empty string")
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parts, extension = _relative_parts(relative)
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candidate, locator = _resolve(root, parts)
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before = self._pre_stat(candidate)
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self._admit(before.st_size, reserve=True)
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try:
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capture = self._copy(
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candidate, locator, extension, before, root_index, epoch, scope
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)
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finally:
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self._release_admission(before.st_size, reserve=True)
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return capture
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def verify(self, root: os.PathLike | str, relative: str) -> FileFacts:
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"""Hash the current rooted file under the same bounds, keeping no copy."""
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parts, _extension = _relative_parts(relative)
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candidate, locator = _resolve(root, parts)
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before = self._pre_stat(candidate)
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self._admit(0, reserve=False)
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try:
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sha256 = self._stream(candidate, locator, before, None)
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finally:
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self._release_admission(0, reserve=False)
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return FileFacts(locator, sha256, before.st_size, before.st_mtime_ns)
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def get(self, token: str) -> Capture | None:
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"""The live capture for *token*, touching its idle clock; else None."""
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with self._lock:
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entry = self._live_locked(token)
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if entry is None:
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return None
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entry.last_used_at = self._clock()
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return entry.capture
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def acquire(self, token: str) -> Capture | None:
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"""Mark the capture in use (inference); it outlives expiry until released."""
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with self._lock:
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entry = self._live_locked(token)
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if entry is None:
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return None
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entry.uses += 1
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entry.last_used_at = self._clock()
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return entry.capture
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def release_use(self, token: str) -> None:
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"""End one ``acquire``; a doomed capture is removed with its last use."""
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with self._lock:
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entry = self._entries.get(token)
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if entry is None:
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return
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entry.uses = max(0, entry.uses - 1)
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entry.last_used_at = self._clock()
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if entry.doomed and entry.uses == 0:
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self._remove_locked(entry)
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def release(self, token: str) -> bool:
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"""Explicit release; True when the token was live."""
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with self._lock:
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entry = self._entries.get(token)
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if entry is None or entry.doomed:
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return False
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self._doom_locked(entry)
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return True
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def invalidate_all(self) -> None:
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"""Expire every capture now (storage epoch changed, restore, shutdown)."""
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with self._lock:
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for entry in list(self._entries.values()):
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self._doom_locked(entry)
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def sweep(self) -> None:
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"""Remove idle and hard-expired captures that are not in use."""
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with self._lock:
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self._sweep_locked(self._clock())
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def expires_in(self, token: str) -> float | None:
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"""Seconds until *token* expires without further use; None when gone."""
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with self._lock:
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entry = self._live_locked(token)
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if entry is None:
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return None
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now = self._clock()
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remaining = self.hard - (now - entry.created_at)
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if entry.uses == 0:
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remaining = min(remaining, self.idle - (now - entry.last_used_at))
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return max(0.0, remaining)
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def stats(self) -> dict:
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with self._lock:
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return {
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"captures": len(self._entries),
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"reserved_bytes": self._completed_bytes + self._pending_bytes,
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"workers": self._workers,
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}
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def close(self) -> None:
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"""Remove every owned capture file and the owned directory. Idempotent."""
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with self._lock:
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self._closed = True
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for entry in list(self._entries.values()):
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self._remove_locked(entry)
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try:
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os.rmdir(self.directory)
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except FileNotFoundError:
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pass
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except OSError as error:
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logger.warning(
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"Capture directory %s could not be removed: %s", self.directory, error
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)
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# -- admission -------------------------------------------------------------
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def _admit(self, size: int, *, reserve: bool) -> None:
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with self._lock:
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if self._closed:
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raise RuntimeError("The capture store is closed")
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self._sweep_locked(self._clock())
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if self._workers >= self.max_workers:
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raise CaptureCapacity("Too many captures are in progress")
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if reserve:
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if len(self._entries) + self._pending >= self.max_captures:
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raise CaptureCapacity("Too many captures are held")
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reserved = self._completed_bytes + self._pending_bytes
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if reserved + size > self.max_bytes:
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raise CaptureCapacity("Capture byte budget exhausted")
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self._pending += 1
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self._pending_bytes += size
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self._workers += 1
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def _release_admission(self, size: int, *, reserve: bool) -> None:
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with self._lock:
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self._workers -= 1
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if reserve:
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self._pending -= 1
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self._pending_bytes -= size
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def _register(self, capture: Capture) -> None:
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with self._lock:
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if self._closed:
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raise RuntimeError("The capture store is closed")
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self._completed_bytes += capture.size
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self._entries[capture.token] = _Entry(capture, self._clock())
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# -- lifetime (all under the lock) -----------------------------------------
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def _expired(self, entry: _Entry, now: float) -> bool:
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if now - entry.created_at >= self.hard:
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return True
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return entry.uses == 0 and now - entry.last_used_at >= self.idle
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def _live_locked(self, token: str) -> _Entry | None:
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entry = self._entries.get(token)
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if entry is None or entry.doomed:
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return None
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if self._expired(entry, self._clock()):
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self._doom_locked(entry)
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return None
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return entry
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def _sweep_locked(self, now: float) -> None:
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for entry in list(self._entries.values()):
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if entry.doomed or self._expired(entry, now):
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self._doom_locked(entry)
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def _doom_locked(self, entry: _Entry) -> None:
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entry.doomed = True
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if entry.uses == 0:
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self._remove_locked(entry)
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def _remove_locked(self, entry: _Entry) -> None:
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_unlink_quietly(entry.capture.path)
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if self._entries.pop(entry.capture.token, None) is not None:
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self._completed_bytes -= entry.capture.size
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# -- copy and hash -----------------------------------------------------------
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def _pre_stat(self, candidate: str) -> os.stat_result:
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try:
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facts = os.lstat(candidate)
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except FileNotFoundError:
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raise CaptureChanged("The file is no longer there") from None
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except OSError as error:
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raise CaptureChanged(f"The file could not be read: {error}") from None
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if stat_module.S_ISLNK(facts.st_mode):
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raise CaptureDenied("Symbolic links are not captured")
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if not stat_module.S_ISREG(facts.st_mode):
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raise CaptureDenied("Only regular files are captured")
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if facts.st_size > self.max_file:
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raise CaptureTooLarge("The file is larger than the capture limit")
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return facts
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def _copy(
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self,
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candidate: str,
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locator: str,
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extension: str,
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before: os.stat_result,
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root_index: int,
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epoch: str,
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scope: str,
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) -> Capture:
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fd, temp_path = tempfile.mkstemp(
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prefix="capture-", suffix=extension, dir=self.directory
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)
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sink = os.fdopen(fd, "wb")
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completed = False
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try:
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sha256 = self._stream(candidate, locator, before, sink)
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sink.close()
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media_type = "video" if is_video_path(candidate) else "image"
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width, height, inferable, reason = self._probe(temp_path, media_type)
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capture = Capture(
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token=secrets.token_urlsafe(32),
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locator=locator,
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root_index=root_index,
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scope=scope,
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epoch=epoch,
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sha256=sha256,
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size=before.st_size,
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mtime_ns=before.st_mtime_ns,
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path=temp_path,
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media_type=media_type,
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width=width,
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height=height,
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inferable=inferable,
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inferable_reason=reason,
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)
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self._register(capture)
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completed = True
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return capture
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finally:
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if not sink.closed:
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sink.close()
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if not completed:
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_unlink_quietly(temp_path)
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def _read(self, stream, size: int) -> bytes:
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"""One bounded read of the source; a seam for change-detection tests."""
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return stream.read(size)
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def _stream(self, candidate: str, locator: str, before, sink) -> str:
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"""Hash (and copy into *sink*) the file; every handle closes here."""
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digest = hashlib.sha256()
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total = 0
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try:
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fd = os.open(candidate, _OPEN_FLAGS)
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except OSError as error:
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raise CaptureChanged(f"The file could not be opened: {error}") from None
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with os.fdopen(fd, "rb") as stream:
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opened = os.fstat(stream.fileno())
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if not _same_file(before, opened, change_time=False):
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raise CaptureChanged("The file changed before it was read")
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while True:
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chunk = self._read(stream, CHUNK_SIZE)
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if not chunk:
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break
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total += len(chunk)
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if total > self.max_file:
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raise CaptureTooLarge("The file grew past the capture limit")
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digest.update(chunk)
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if sink is not None:
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sink.write(chunk)
|
|
after = os.fstat(stream.fileno())
|
|
if (
|
|
total != before.st_size
|
|
or not _same_file(opened, after, change_time=True)
|
|
or not _same_file(before, after, change_time=False)
|
|
):
|
|
raise CaptureChanged("The file changed while it was read")
|
|
try:
|
|
current = os.stat(candidate)
|
|
except OSError:
|
|
raise CaptureChanged("The file is no longer there") from None
|
|
if not _same_file(before, current, change_time=False):
|
|
raise CaptureChanged("The path names another file now")
|
|
if os.path.normcase(os.path.realpath(candidate)) != locator:
|
|
raise CaptureChanged("The path resolves elsewhere now")
|
|
return digest.hexdigest()
|
|
|
|
def _probe(self, path: str, media_type: str):
|
|
"""Header-only dimensions of the capture; never decodes pixels."""
|
|
if media_type == "video":
|
|
return None, None, False, VIDEO_ONLY_REASON
|
|
try:
|
|
with warnings.catch_warnings():
|
|
warnings.simplefilter("ignore", Image.DecompressionBombWarning)
|
|
read = read_inspection_file(Path(path))
|
|
except (MetadataReadError, Image.DecompressionBombError):
|
|
return None, None, False, HEADER_REASON
|
|
width, height = read.width, read.height
|
|
if width is None or height is None:
|
|
return None, None, False, HEADER_REASON
|
|
if (
|
|
width > MAX_INFERENCE_SIDE
|
|
or height > MAX_INFERENCE_SIDE
|
|
or width * height > MAX_INFERENCE_PIXELS
|
|
):
|
|
return width, height, False, DIMENSION_REASON
|
|
return width, height, True, None
|
|
|
|
|
|
def _relative_parts(relative) -> tuple[list[str], str]:
|
|
"""Split a safe relative POSIX media path; anything else is denied."""
|
|
if not isinstance(relative, str) or not relative:
|
|
raise CaptureDenied("Invalid file path")
|
|
if len(relative) > MAX_RELATIVE_LENGTH or "\x00" in relative:
|
|
raise CaptureDenied("Invalid file path")
|
|
if "\\" in relative or relative.startswith("/"):
|
|
raise CaptureDenied("Invalid file path")
|
|
parts = relative.split("/")
|
|
for part in parts:
|
|
if part in ("", ".", "..") or ":" in part:
|
|
raise CaptureDenied("Invalid file path")
|
|
extension = os.path.splitext(parts[-1])[1].lower()
|
|
if extension not in CAPTURE_EXTENSIONS:
|
|
raise CaptureDenied("Unsupported media type")
|
|
return parts, extension
|
|
|
|
|
|
def _resolve(root, parts: list[str]) -> tuple[str, str]:
|
|
"""The candidate path and its locator; aliases and escapes are denied."""
|
|
real_root = os.path.realpath(os.fspath(root))
|
|
if not os.path.isdir(real_root):
|
|
raise CaptureDenied("Unknown gallery root")
|
|
candidate = os.path.join(real_root, *parts)
|
|
locator = os.path.normcase(candidate)
|
|
if os.path.normcase(os.path.realpath(candidate)) != locator:
|
|
raise CaptureDenied("The file is not a listed rooted file")
|
|
return candidate, locator
|