OCRmyPDF/tests/plugins/tesseract_cache.py

207 lines
7.5 KiB
Python

# © 2020 James R. Barlow: github.com/jbarlow83
#
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# The above copyright notice and this permission notice shall be included
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# OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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"""Cache output of tesseract to speed up test suite
The cache is keyed by by the input test file The input arguments are slugged
into a hideous filename that more or less represents them literally. Joined
together, this becomes the name of the cache folder. A few name files like
stdout, stderr, hocr, pdf, describe the output to reproduce.
Changes to tests/resources/ or image processing algorithms don't trigger a
cache miss. By design, an input image that varies according to platform
differences (e.g. JPEG decoders are allowed to produce differing outputs,
and in practice they do) will still be a cache hit. By design, an
invocation of tesseract with the same parameters from a different test case
will be a hit. It's fragile.
The tests/cache/manifest.jsonl is a JSON lines file that contains
information about the system that produced the results used when cache was
generated. This mainly a log to answer questions about how the files
were produced.
Certain operations are not cached and routed to Tesseract OCR directly.
Assumes Tesseract 4.0.0-alpha or higher.
"""
import argparse
import json
import logging
import platform
import re
import shutil
from functools import partial
from pathlib import Path
from subprocess import PIPE, CalledProcessError, CompletedProcess
from unittest.mock import patch
from ocrmypdf import hookimpl
from ocrmypdf.builtin_plugins.tesseract_ocr import TesseractOcrEngine
from ocrmypdf.subprocess import run
log = logging.getLogger(__name__)
TESTS_ROOT = Path(__file__).resolve().parent.parent
CACHE_ROOT = TESTS_ROOT / 'cache'
parser = argparse.ArgumentParser(
prog='tesseract-cache', description='cache output of tesseract'
)
parser.add_argument('-l', '--language', action='append')
parser.add_argument('imagename')
parser.add_argument('outputbase')
parser.add_argument('configfiles', nargs='*')
parser.add_argument('--user-words', type=str)
parser.add_argument('--user-patterns', type=str)
parser.add_argument('-c', action='append')
parser.add_argument('--psm', type=int)
parser.add_argument('--oem', type=int)
def get_cache_folder(source_pdf, run_args, parsed_args):
def slugs():
yield '' # so we don't start with a '-' which makes rm difficult
for arg in run_args[1:]:
if arg == parsed_args.imagename:
yield Path(parsed_args.imagename).name
elif arg == parsed_args.outputbase:
yield Path(parsed_args.outputbase).name
elif arg == '-c' or arg.startswith('textonly'):
pass
else:
yield arg
argv_slug = '__'.join(slugs())
argv_slug = argv_slug.replace('/', '___')
return Path(CACHE_ROOT) / Path(source_pdf).stem / argv_slug
def cached_run(options, run_args, **run_kwargs):
run_args = [str(arg) for arg in run_args] # flatten PosixPaths
args = parser.parse_args(run_args[1:])
if args.imagename in ('stdin', '-'):
return run(run_args, **run_kwargs)
source_file = options.input_file
cache_folder = get_cache_folder(source_file, run_args, args)
cache_folder.mkdir(parents=True, exist_ok=True)
log.debug(f"Using Tesseract cache {cache_folder}")
if (cache_folder / 'stderr.bin').exists():
log.debug("Cache HIT")
# Replicate stdout/err
if args.outputbase != 'stdout':
if not args.configfiles:
args.configfiles.append('txt')
for configfile in args.configfiles:
# cp cache -> output
tessfile = args.outputbase + '.' + configfile
shutil.copy(str(cache_folder / configfile) + '.bin', tessfile)
return CompletedProcess(
args=run_args,
returncode=0,
stdout=(cache_folder / 'stdout.bin').read_bytes(),
stderr=(cache_folder / 'stderr.bin').read_bytes(),
)
log.debug("Cache MISS")
cache_kwargs = {
k: v for k, v in run_kwargs.items() if k not in ('stdout', 'stderr')
}
assert cache_kwargs['check']
try:
p = run(run_args, stdout=PIPE, stderr=PIPE, **cache_kwargs)
except CalledProcessError as e:
log.exception(e)
raise # Pass exception onward
# Update cache
(cache_folder / 'stdout.bin').write_bytes(p.stdout)
(cache_folder / 'stderr.bin').write_bytes(p.stderr)
if args.outputbase != 'stdout':
if not args.configfiles:
args.configfiles.append('txt')
for configfile in args.configfiles:
if configfile not in ('hocr', 'pdf', 'txt'):
continue
# cp pwd/{outputbase}.{configfile} -> {cache}/{configfile}
tessfile = args.outputbase + '.' + configfile
shutil.copy(tessfile, str(cache_folder / configfile) + '.bin')
manifest = {}
manifest['tesseract_version'] = TesseractOcrEngine.version().replace('\n', ' ')
manifest['system'] = platform.system()
manifest['python'] = platform.python_version()
manifest['argv_slug'] = cache_folder.name
manifest['sourcefile'] = str(Path(source_file).relative_to(TESTS_ROOT))
def clean_sys_argv():
for arg in run_args[1:]:
yield re.sub(r'.*/ocrmypdf[.]io[.][^/]+[/](.*)', r'$TMPDIR/\1', arg)
manifest['args'] = list(clean_sys_argv())
with (Path(CACHE_ROOT) / 'manifest.jsonl').open('a') as f:
json.dump(manifest, f)
f.write('\n')
f.flush()
return p
class CacheOcrEngine(TesseractOcrEngine):
@staticmethod
def get_orientation(input_file, options):
with patch('ocrmypdf._exec.tesseract.run', new=partial(cached_run, options)):
return TesseractOcrEngine.get_orientation(input_file, options)
@staticmethod
def get_deskew(input_file, options) -> float:
with patch('ocrmypdf._exec.tesseract.run', new=partial(cached_run, options)):
return TesseractOcrEngine.get_deskew(input_file, options)
@staticmethod
def generate_hocr(input_file, output_hocr, output_text, options):
with patch('ocrmypdf._exec.tesseract.run', new=partial(cached_run, options)):
TesseractOcrEngine.generate_hocr(
input_file, output_hocr, output_text, options
)
@staticmethod
def generate_pdf(input_file, output_pdf, output_text, options):
with patch('ocrmypdf._exec.tesseract.run', new=partial(cached_run, options)):
TesseractOcrEngine.generate_pdf(
input_file, output_pdf, output_text, options
)
@hookimpl
def get_ocr_engine():
return CacheOcrEngine()