258 lines
7.7 KiB
Python
258 lines
7.7 KiB
Python
# © 2016 James R. Barlow: github.com/jbarlow83
|
|
#
|
|
# This Source Code Form is subject to the terms of the Mozilla Public
|
|
# License, v. 2.0. If a copy of the MPL was not distributed with this
|
|
# file, You can obtain one at http://mozilla.org/MPL/2.0/.
|
|
|
|
|
|
import logging
|
|
import multiprocessing
|
|
import os
|
|
import shutil
|
|
import warnings
|
|
from collections import namedtuple
|
|
from collections.abc import Iterable
|
|
from contextlib import suppress
|
|
from functools import wraps
|
|
from io import StringIO
|
|
from math import isclose
|
|
from pathlib import Path
|
|
from typing import Any, Sequence
|
|
|
|
import pikepdf
|
|
|
|
log = logging.getLogger(__name__)
|
|
|
|
|
|
class Resolution(namedtuple('Resolution', ('x', 'y'))):
|
|
"""The number of pixels per inch in each 2D direction."""
|
|
|
|
__slots__ = ()
|
|
|
|
def round(self, ndigits: int):
|
|
return Resolution(round(self.x, ndigits), round(self.y, ndigits))
|
|
|
|
def to_int(self):
|
|
return Resolution(int(round(self.x)), int(round(self.y)))
|
|
|
|
@property
|
|
def is_square(self) -> bool:
|
|
return isclose(self.x, self.y, rel_tol=1e-3)
|
|
|
|
def take_max(self, vals, yvals=None):
|
|
if yvals is not None:
|
|
return Resolution(max(self.x, *vals), max(self.y, *yvals))
|
|
max_x, max_y = self.x, self.y
|
|
for x, y in vals:
|
|
max_x = max(x, max_x)
|
|
max_y = max(y, max_y)
|
|
return Resolution(max_x, max_y)
|
|
|
|
def flip_axis(self):
|
|
return Resolution(self.y, self.x)
|
|
|
|
def __str__(self):
|
|
return f"{self.x:f}x{self.y:f}"
|
|
|
|
def __repr__(self):
|
|
return f"Resolution({self.x}x{self.y} dpi)"
|
|
|
|
|
|
class NeverRaise(Exception):
|
|
"""An exception that is never raised"""
|
|
|
|
|
|
def safe_symlink(input_file: os.PathLike, soft_link_name: os.PathLike):
|
|
"""Create a symbolic link at ``soft_link_name``, which references ``input_file``.
|
|
|
|
Think of this as copying ``input_file`` to ``soft_link_name`` with less overhead.
|
|
|
|
Use symlinks safely. Self-linking loops are prevented. On Windows, file copy is
|
|
used since symlinks may require administrator privileges. An existing link at the
|
|
destination is removed.
|
|
"""
|
|
input_file = os.fspath(input_file)
|
|
soft_link_name = os.fspath(soft_link_name)
|
|
|
|
# Guard against soft linking to oneself
|
|
if input_file == soft_link_name:
|
|
log.warning(
|
|
"No symbolic link created. You are using the original data directory "
|
|
"as the working directory."
|
|
)
|
|
return
|
|
|
|
# Soft link already exists: delete for relink?
|
|
if os.path.lexists(soft_link_name):
|
|
# do not delete or overwrite real (non-soft link) file
|
|
if not os.path.islink(soft_link_name):
|
|
raise FileExistsError(f"{soft_link_name} exists and is not a link")
|
|
try:
|
|
os.unlink(soft_link_name)
|
|
except OSError:
|
|
log.debug("Can't unlink %s", soft_link_name)
|
|
|
|
if not os.path.exists(input_file):
|
|
raise FileNotFoundError(f"trying to create a broken symlink to {input_file}")
|
|
|
|
if os.name == 'nt':
|
|
# Don't actually use symlinks on Windows due to permission issues
|
|
shutil.copyfile(input_file, soft_link_name)
|
|
return
|
|
|
|
log.debug("os.symlink(%s, %s)", input_file, soft_link_name)
|
|
|
|
# Create symbolic link using absolute path
|
|
os.symlink(os.path.abspath(input_file), soft_link_name)
|
|
|
|
|
|
def samefile(f1: os.PathLike, f2: os.PathLike):
|
|
if os.name == 'nt':
|
|
return f1 == f2
|
|
else:
|
|
return os.path.samefile(f1, f2)
|
|
|
|
|
|
def is_iterable_notstr(thing: Any) -> bool:
|
|
"""Is this is an iterable type, other than a string?"""
|
|
return isinstance(thing, Iterable) and not isinstance(thing, str)
|
|
|
|
|
|
def monotonic(L: Sequence) -> bool:
|
|
"""Does this sequence increase monotonically?"""
|
|
return all(b > a for a, b in zip(L, L[1:]))
|
|
|
|
|
|
def page_number(input_file: os.PathLike) -> int:
|
|
"""Get one-based page number implied by filename (000002.pdf -> 2)"""
|
|
return int(os.path.basename(os.fspath(input_file))[0:6])
|
|
|
|
|
|
def available_cpu_count() -> int:
|
|
"""Returns number of CPUs in the system."""
|
|
try:
|
|
return multiprocessing.cpu_count()
|
|
except NotImplementedError:
|
|
pass
|
|
warnings.warn(
|
|
"Could not get CPU count. Assuming one (1) CPU." "Use -j N to set manually."
|
|
)
|
|
return 1
|
|
|
|
|
|
def is_file_writable(test_file: os.PathLike) -> bool:
|
|
"""Intentionally racy test if target is writable.
|
|
|
|
We intend to write to the output file if and only if we succeed and
|
|
can replace it atomically. Before doing the OCR work, make sure
|
|
the location is writable.
|
|
"""
|
|
try:
|
|
p = Path(test_file)
|
|
if p.is_symlink():
|
|
p = p.resolve(strict=False)
|
|
|
|
# p.is_file() throws an exception in some cases
|
|
if p.exists() and p.is_file():
|
|
return os.access(
|
|
os.fspath(p),
|
|
os.W_OK,
|
|
effective_ids=(os.access in os.supports_effective_ids),
|
|
)
|
|
else:
|
|
try:
|
|
fp = p.open('wb')
|
|
except OSError:
|
|
return False
|
|
else:
|
|
fp.close()
|
|
with suppress(OSError):
|
|
p.unlink()
|
|
return True
|
|
except (EnvironmentError, RuntimeError) as e:
|
|
log.debug(e)
|
|
log.error(str(e))
|
|
return False
|
|
|
|
|
|
def check_pdf(input_file: Path) -> bool:
|
|
"""Check if a PDF complies with the PDF specification.
|
|
|
|
Checks for proper formatting and proper linearization. Uses pikepdf (which in
|
|
turn, uses QPDF) to perform the checks.
|
|
"""
|
|
pdf = None
|
|
try:
|
|
pdf = pikepdf.open(input_file)
|
|
except pikepdf.PdfError as e:
|
|
log.error(e)
|
|
return False
|
|
else:
|
|
messages = pdf.check()
|
|
for msg in messages:
|
|
if 'error' in msg.lower():
|
|
log.error(msg)
|
|
else:
|
|
log.warning(msg)
|
|
|
|
sio = StringIO()
|
|
linearize_msgs = ''
|
|
try:
|
|
# If linearization is missing entirely, we do not complain. We do
|
|
# complain if linearization is present but incorrect.
|
|
pdf.check_linearization(sio)
|
|
except RuntimeError:
|
|
pass
|
|
except (
|
|
getattr(pikepdf, 'ForeignObjectError')
|
|
if pikepdf.__version__ == '2.1.0' # This version may throw wrong exception
|
|
else NeverRaise
|
|
):
|
|
pass
|
|
else:
|
|
linearize_msgs = sio.getvalue()
|
|
if linearize_msgs:
|
|
log.warning(linearize_msgs)
|
|
|
|
if not messages and not linearize_msgs:
|
|
return True
|
|
return False
|
|
finally:
|
|
if pdf:
|
|
pdf.close()
|
|
|
|
|
|
def clamp(n, smallest, largest): # mypy doesn't understand types for this
|
|
"""Clamps the value of ``n`` to between ``smallest`` and ``largest``."""
|
|
return max(smallest, min(n, largest))
|
|
|
|
|
|
def pikepdf_enable_mmap():
|
|
# try:
|
|
# if pikepdf._qpdf.set_access_default_mmap(True):
|
|
# log.debug("pikepdf mmap enabled")
|
|
# except AttributeError:
|
|
# log.debug("pikepdf mmap not available")
|
|
# We found a race condition probably related to pybind issue #2252 that can
|
|
# cause a crash. For now, disable pikepdf mmap to be on the safe side.
|
|
# Fix is not in pybind11 2.6.0
|
|
log.debug("pikepdf mmap disabled")
|
|
return
|
|
|
|
|
|
def deprecated(func):
|
|
"""Warn that function is deprecated."""
|
|
|
|
@wraps(func)
|
|
def new_func(*args, **kwargs):
|
|
warnings.simplefilter('always', DeprecationWarning) # turn off filter
|
|
warnings.warn(
|
|
"Call to deprecated function {}.".format(func.__name__),
|
|
category=DeprecationWarning,
|
|
stacklevel=2,
|
|
)
|
|
warnings.simplefilter('default', DeprecationWarning) # reset filter
|
|
return func(*args, **kwargs)
|
|
|
|
return new_func
|