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[Windows] Workaround for loading bundled DLLs #4893

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Merged
merged 5 commits into from
Dec 13, 2021
Merged

[Windows] Workaround for loading bundled DLLs #4893

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9806ba3
[Windows] Workaround for loading bundled DLLs
malfet Nov 10, 2021
24ee977
Address review feedback
malfet Nov 10, 2021
b09f632
More review feedback addressed
malfet Dec 13, 2021
52a6e14
Move `_load_library` to `torchvision.extension`
malfet Dec 13, 2021
a5babfb
Remove type annotations to pacify linter
malfet Dec 13, 2021
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23 changes: 23 additions & 0 deletions torchvision/extension.py
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Original file line number Diff line number Diff line change
@@ -1,3 +1,8 @@
import ctypes
import os
import sys
from warnings import warn

import torch

from ._internally_replaced_utils import _get_extension_path
Expand Down Expand Up @@ -67,4 +72,22 @@ def _check_cuda_version():
return _version


def _load_library(lib_name):
lib_path = _get_extension_path(lib_name)
# On Windows Python-3.8+ has `os.add_dll_directory` call,
# which is called from _get_extension_path to configure dll search path
# Condition below adds a workaround for older versions by
# explicitly calling `LoadLibraryExW` with the following flags:
# - LOAD_LIBRARY_SEARCH_DEFAULT_DIRS (0x1000)
# - LOAD_LIBRARY_SEARCH_DLL_LOAD_DIR (0x100)
if os.name == "nt" and sys.version_info < (3, 8):
_kernel32 = ctypes.WinDLL("kernel32.dll", use_last_error=True)
if hasattr(_kernel32, "LoadLibraryExW"):
_kernel32.LoadLibraryExW(lib_path, None, 0x00001100)
else:
warn("LoadLibraryExW is missing in kernel32.dll")

torch.ops.load_library(lib_path)


_check_cuda_version()
5 changes: 2 additions & 3 deletions torchvision/io/_video_opt.py
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Original file line number Diff line number Diff line change
Expand Up @@ -5,12 +5,11 @@

import torch

from .._internally_replaced_utils import _get_extension_path
from ..extension import _load_library


try:
lib_path = _get_extension_path("video_reader")
torch.ops.load_library(lib_path)
_load_library("video_reader")
_HAS_VIDEO_OPT = True
except (ImportError, OSError):
_HAS_VIDEO_OPT = False
Expand Down
10 changes: 5 additions & 5 deletions torchvision/io/image.py
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Original file line number Diff line number Diff line change
@@ -1,15 +1,15 @@
from enum import Enum
from warnings import warn

import torch

from .._internally_replaced_utils import _get_extension_path
from ..extension import _load_library


try:
lib_path = _get_extension_path("image")
torch.ops.load_library(lib_path)
except (ImportError, OSError):
pass
_load_library("image")
except (ImportError, OSError) as e:
warn(f"Failed to load image Python extension: {e}")
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Is there a reason that this was changed from pass to warn? When running pytest on my project, I see warnings like:

../.spack/.spack-env/view/lib/python3.9/site-packages/torchvision/io/image.py:11
  /Users/Adam/.spack/.spack-env/view/lib/python3.9/site-packages/torchvision/io/image.py:11: UserWarning: Failed to load image Python extension: 
    warn(f"Failed to load image Python extension: {e}")

It's unclear if this is a serious bug in my installation that I should fix, or something I can safely ignore. FWIW, I'm using the pillow-SIMD backend.



class ImageReadMode(Enum):
Expand Down