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OCRmyPDF/src/ocrmypdf/_sync.py
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Python

# © 2016 James R. Barlow: github.com/jbarlow83
#
# This file is part of OCRmyPDF.
#
# OCRmyPDF is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# OCRmyPDF is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with OCRmyPDF. If not, see <http://www.gnu.org/licenses/>.
import atexit
import logging
import logging.handlers
import multiprocessing
import os
import signal
import sys
import threading
from collections import namedtuple
from tempfile import mkdtemp
from tqdm import tqdm
from . import VERSION
from ._jobcontext import PDFContext, cleanup_working_files, make_logger
from ._pipeline import (
convert_to_pdfa,
copy_final,
create_ocr_image,
create_pdf_page_from_image,
create_visible_page_jpg,
generate_postscript_stub,
get_orientation_correction,
get_pdfinfo,
is_ocr_required,
merge_sidecars,
metadata_fixup,
ocr_tesseract_hocr,
ocr_tesseract_textonly_pdf,
optimize_pdf,
preprocess_clean,
preprocess_deskew,
preprocess_remove_background,
rasterize,
rasterize_preview,
render_hocr_page,
should_visible_page_image_use_jpg,
triage,
validate_pdfinfo_options,
)
from ._validation import (
check_dependency_versions,
check_environ,
check_options,
check_requested_output_file,
create_input_file,
report_output_file_size,
)
from ._weave import OcrGrafter
from .exceptions import ExitCode, ExitCodeException
from .exec import qpdf
from .helpers import available_cpu_count
from .pdfa import file_claims_pdfa
PageResult = namedtuple(
'PageResult', 'pageno, pdf_page_from_image, ocr, text, orientation_correction'
)
def exec_page_sync(page_context):
options = page_context.options
orientation_correction = 0
pdf_page_from_image_out = None
ocr_out = None
text_out = None
if is_ocr_required(page_context):
if options.rotate_pages:
# Rasterize
rasterize_preview_out = rasterize_preview(page_context.origin, page_context)
orientation_correction = get_orientation_correction(
rasterize_preview_out, page_context
)
rasterize_out = rasterize(
page_context.origin, page_context, correction=orientation_correction
)
preprocess_out = rasterize_out
if options.remove_background:
preprocess_out = preprocess_remove_background(preprocess_out, page_context)
if options.deskew:
preprocess_out = preprocess_deskew(preprocess_out, page_context)
if options.clean:
preprocess_out = preprocess_clean(preprocess_out, page_context)
ocr_image_out = create_ocr_image(preprocess_out, page_context)
pdf_page_from_image_out = None
if not options.lossless_reconstruction:
visible_image_out = preprocess_out
if should_visible_page_image_use_jpg(page_context.pageinfo):
visible_image_out = create_visible_page_jpg(
visible_image_out, page_context
)
pdf_page_from_image_out = create_pdf_page_from_image(
visible_image_out, page_context
)
if options.pdf_renderer == 'hocr':
(hocr_out, text_out) = ocr_tesseract_hocr(ocr_image_out, page_context)
ocr_out = render_hocr_page(hocr_out, page_context)
if options.pdf_renderer == 'sandwich':
(ocr_out, text_out) = ocr_tesseract_textonly_pdf(
ocr_image_out, page_context
)
return PageResult(
pageno=page_context.pageno,
pdf_page_from_image=pdf_page_from_image_out,
ocr=ocr_out,
text=text_out,
orientation_correction=orientation_correction,
)
def post_process(pdf_file, context):
pdf_out = pdf_file
if context.options.output_type.startswith('pdfa'):
ps_stub_out = generate_postscript_stub(context)
pdf_out = convert_to_pdfa(pdf_out, ps_stub_out, context)
pdf_out = metadata_fixup(pdf_out, context)
return optimize_pdf(pdf_out, context)
def worker_init(queue):
"""Initialize a process pool worker"""
# Ignore SIGINT (our parent process will kill us gracefully)
signal.signal(signal.SIGINT, signal.SIG_IGN)
# Reconfigure the root logger for this process to send all messages to a queue
h = logging.handlers.QueueHandler(queue)
root = logging.getLogger()
root.handlers = []
root.addHandler(h)
def log_listener(queue):
"""Listen to the worker processes and forward the messages to logging
For simplicity this is a thread rather than a process. Only one process
should actually write to sys.stderr or whatever we're using, so if this is
made into a process the main application needs to be directed to it.
See https://docs.python.org/3/howto/logging-cookbook.html#logging-to-a-single-file-from-multiple-processes
"""
while True:
try:
record = queue.get()
if record is None:
break
logger = logging.getLogger(record.name)
logger.handle(record)
except Exception:
import traceback
print("Logging problem", file=sys.stderr)
traceback.print_exc(file=sys.stderr)
def exec_concurrent(context):
"""Execute the pipeline concurrently"""
# Run exec_page_sync on every page context
max_workers = min(len(context.pdfinfo), context.options.jobs)
if max_workers > 1:
context.log.info("Start processing %d pages concurrent" % max_workers)
sidecars = [None] * len(context.pdfinfo)
ocrgraft = OcrGrafter(context)
log_queue = multiprocessing.Queue(-1)
listener = threading.Thread(target=log_listener, args=(log_queue,))
listener.start()
with tqdm(
total=(2 * len(context.pdfinfo)), desc='OCR', unit='page', unit_scale=0.5
) as pbar, multiprocessing.Pool(
processes=max_workers, initializer=worker_init, initargs=(log_queue,)
) as pool:
results = pool.imap_unordered(exec_page_sync, context.get_page_contexts())
while True:
try:
page_result = results.next()
sidecars[page_result.pageno] = page_result.text
pbar.update()
ocrgraft.graft_page(page_result)
pbar.update()
except StopIteration:
break
except (Exception, KeyboardInterrupt):
pool.terminate()
log_queue.put_nowait(None) # Terminate log listener
# Don't try listener.join() here, will deadlock
raise
log_queue.put_nowait(None)
listener.join()
# Output sidecar text
if context.options.sidecar:
text = merge_sidecars(sidecars, context)
# Copy text file to destination
copy_final(text, context.options.sidecar, context)
# Merge layers to one single pdf
# pdf = weave_layers(layers, context)
pdf = ocrgraft.finalize()
# PDF/A and metadata
pdf = post_process(pdf, context)
# Copy PDF file to destination
copy_final(pdf, context.options.output_file, context)
def run_pipeline(options):
log = make_logger(options, __name__)
log.debug('ocrmypdf ' + VERSION)
result = check_options(options)
if result != ExitCode.ok:
return result
check_dependency_versions(options)
# Any changes to options will not take effect for options that are already
# bound to function parameters in the pipeline. (For example
# options.input_file, options.pdf_renderer are already bound.)
if not options.jobs:
options.jobs = available_cpu_count()
# Performance is improved by setting Tesseract to single threaded. In tests
# this gives better throughput than letting a smaller number of Tesseract
# jobs run multithreaded. Same story for pngquant. Tess <4 ignores this
# variable, but harmless to set if ignored.
os.environ.setdefault('OMP_THREAD_LIMIT', '1')
check_environ(options)
work_folder = mkdtemp(prefix="com.github.ocrmypdf.")
atexit.register(cleanup_working_files, work_folder, options)
try:
check_requested_output_file(options)
start_input_file = create_input_file(options, work_folder)
# Triage image or pdf
origin_pdf = triage(
start_input_file, os.path.join(work_folder, 'origin.pdf'), options, log
)
# Gather pdfinfo and create context
pdfinfo = get_pdfinfo(origin_pdf, detailed_page_analysis=options.redo_ocr)
context = PDFContext(options, work_folder, origin_pdf, pdfinfo)
# Validate options are okay for this pdf
validate_pdfinfo_options(context)
# Execute the pipeline
exec_concurrent(context)
except KeyboardInterrupt as e:
log.error("KeyboardInterrupt")
return ExitCode.ctrl_c
except ExitCodeException as e:
log.error("%s: %s" % (type(e).__name__, str(e)))
return e.exit_code
except Exception as e:
log.exception("An exception occurred while executing the pipeline")
return ExitCode.other_error
if options.output_file == '-':
log.info("Output sent to stdout")
elif os.path.samefile(options.output_file, os.devnull):
pass # Say nothing when sending to dev null
else:
if options.output_type.startswith('pdfa'):
pdfa_info = file_claims_pdfa(options.output_file)
if pdfa_info['pass']:
msg = f"Output file is a {pdfa_info['conformance']} (as expected)"
log.info(msg)
else:
msg = (
f"Output file is okay but is not PDF/A "
f"(seems to be {pdfa_info['conformance']})"
)
log.warning(msg)
return ExitCode.pdfa_conversion_failed
if not qpdf.check(options.output_file, log):
log.warning('Output file: The generated PDF is INVALID')
return ExitCode.invalid_output_pdf
report_output_file_size(options, start_input_file, options.output_file)
return ExitCode.ok