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https://github.com/ocrmypdf/OCRmyPDF.git
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e613db6a82
Ghostscript 10.6 has a bug that truncates JPEG data by 1-15 bytes. This adds detection and repair by comparing output images to input images and restoring the original bytes when truncation is detected. - Add warning when GS 10.6+ is used with PDF/A output - Add _repair_gs106_jpeg_corruption() to fix damaged JPEGs after Ghostscript processing - Add unit tests for the repair function
408 lines
15 KiB
Python
408 lines
15 KiB
Python
# SPDX-FileCopyrightText: 2022 James R. Barlow
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# SPDX-License-Identifier: MPL-2.0
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from __future__ import annotations
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import logging
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import secrets
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import subprocess
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import sys
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from decimal import Decimal
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from unittest.mock import patch
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import pikepdf
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import pytest
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from packaging.version import Version
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from PIL import Image, UnidentifiedImageError
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from ocrmypdf._exec import ghostscript
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from ocrmypdf._exec.ghostscript import DuplicateFilter, rasterize_pdf
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from ocrmypdf.builtin_plugins.ghostscript import _repair_gs106_jpeg_corruption
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from ocrmypdf.exceptions import ColorConversionNeededError, ExitCode, InputFileError
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from ocrmypdf.helpers import Resolution
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from .conftest import check_ocrmypdf, run_ocrmypdf_api
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# pylint: disable=redefined-outer-name
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@pytest.fixture
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def francais(resources):
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path = resources / 'francais.pdf'
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return path, pikepdf.open(path)
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def test_rasterize_size(francais, outdir):
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path, pdf = francais
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page_size_pts = (pdf.pages[0].mediabox[2], pdf.pages[0].mediabox[3])
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assert pdf.pages[0].mediabox[0] == pdf.pages[0].mediabox[1] == 0
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page_size = (page_size_pts[0] / Decimal(72), page_size_pts[1] / Decimal(72))
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target_size = Decimal('50.0'), Decimal('30.0')
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forced_dpi = Resolution(42.0, 4242.0)
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rasterize_pdf(
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path,
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outdir / 'out.png',
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raster_device='pngmono',
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raster_dpi=Resolution(
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target_size[0] / page_size[0], target_size[1] / page_size[1]
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),
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page_dpi=forced_dpi,
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)
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with Image.open(outdir / 'out.png') as im:
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assert im.size == target_size
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assert im.info['dpi'] == forced_dpi
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def test_rasterize_rotated(francais, outdir, caplog):
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path, pdf = francais
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page_size_pts = (pdf.pages[0].mediabox[2], pdf.pages[0].mediabox[3])
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assert pdf.pages[0].mediabox[0] == pdf.pages[0].mediabox[1] == 0
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page_size = (page_size_pts[0] / Decimal(72), page_size_pts[1] / Decimal(72))
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target_size = Decimal('50.0'), Decimal('30.0')
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forced_dpi = Resolution(42.0, 4242.0)
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caplog.set_level(logging.DEBUG)
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rasterize_pdf(
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path,
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outdir / 'out.png',
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raster_device='pngmono',
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raster_dpi=Resolution(
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target_size[0] / page_size[0], target_size[1] / page_size[1]
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),
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page_dpi=forced_dpi,
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rotation=90,
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)
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with Image.open(outdir / 'out.png') as im:
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assert im.size == (target_size[1], target_size[0])
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assert im.info['dpi'] == forced_dpi.flip_axis()
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def test_gs_render_failure(resources, outpdf, caplog):
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exitcode = run_ocrmypdf_api(
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resources / 'blank.pdf',
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outpdf,
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'--plugin',
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'tests/plugins/tesseract_noop.py',
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'--plugin',
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'tests/plugins/gs_render_failure.py',
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)
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assert 'TEST ERROR: gs_render_failure.py' in caplog.text
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assert exitcode == ExitCode.child_process_error
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def test_gs_raster_failure(resources, outpdf, caplog):
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exitcode = run_ocrmypdf_api(
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resources / 'francais.pdf',
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outpdf,
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'--plugin',
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'tests/plugins/tesseract_noop.py',
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'--plugin',
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'tests/plugins/gs_raster_failure.py',
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)
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assert 'TEST ERROR: gs_raster_failure.py' in caplog.text
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assert exitcode == ExitCode.child_process_error
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def test_ghostscript_pdfa_failure(resources, outpdf, caplog):
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exitcode = run_ocrmypdf_api(
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resources / 'francais.pdf',
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outpdf,
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'--plugin',
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'tests/plugins/tesseract_noop.py',
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'--plugin',
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'tests/plugins/gs_pdfa_failure.py',
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)
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assert (
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exitcode == ExitCode.pdfa_conversion_failed
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), "Unexpected return when PDF/A fails"
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def test_ghostscript_feature_elision(resources, outpdf):
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check_ocrmypdf(
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resources / 'francais.pdf',
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outpdf,
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'--plugin',
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'tests/plugins/tesseract_noop.py',
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'--plugin',
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'tests/plugins/gs_feature_elision.py',
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)
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def test_ghostscript_mandatory_color_conversion(resources, outpdf):
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with pytest.raises(ColorConversionNeededError):
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check_ocrmypdf(
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resources / 'jbig2_baddevicen.pdf',
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outpdf,
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'--plugin',
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'tests/plugins/tesseract_noop.py',
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)
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def test_rasterize_pdf_errors(resources, no_outpdf, caplog):
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with patch('ocrmypdf._exec.ghostscript.run') as mock:
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# ghostscript can produce empty files with return code 0
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mock.return_value = subprocess.CompletedProcess(
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['fakegs'], returncode=0, stdout=b'', stderr=b'error this is an error'
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)
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with pytest.raises(UnidentifiedImageError):
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rasterize_pdf(
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resources / 'francais.pdf',
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no_outpdf,
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raster_device='pngmono',
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raster_dpi=Resolution(100, 100),
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)
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assert "this is an error" in caplog.text
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assert "invalid page image file" in caplog.text
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class TestDuplicateFilter:
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@pytest.fixture(scope='function')
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def duplicate_filter_logger(self):
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# token_urlsafe: ensure the logger has a unique name so tests are isolated
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logger = logging.getLogger(__name__ + secrets.token_urlsafe(8))
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logger.setLevel(logging.DEBUG)
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logger.addFilter(DuplicateFilter(logger))
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return logger
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@pytest.mark.xfail(
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(3, 13, 3) <= sys.version_info[:3] <= (3, 13, 5),
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reason="https://github.com/python/cpython/pull/135858",
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)
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def test_filter_duplicate_messages(self, duplicate_filter_logger, caplog):
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log = duplicate_filter_logger
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log.error("test error message")
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log.error("test error message")
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log.error("test error message")
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log.error("another error message")
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log.error("another error message")
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log.error("yet another error message")
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assert len(caplog.records) == 5
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assert caplog.records[0].msg == "test error message"
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assert caplog.records[1].msg == "(suppressed 2 repeated lines)"
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assert caplog.records[2].msg == "another error message"
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assert caplog.records[3].msg == "(suppressed 1 repeated lines)"
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assert caplog.records[4].msg == "yet another error message"
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def test_filter_does_not_affect_unique_messages(
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self, duplicate_filter_logger, caplog
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):
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log = duplicate_filter_logger
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log.error("test error message")
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log.error("another error message")
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log.error("yet another error message")
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assert len(caplog.records) == 3
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assert caplog.records[0].msg == "test error message"
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assert caplog.records[1].msg == "another error message"
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assert caplog.records[2].msg == "yet another error message"
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@pytest.mark.xfail(
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(3, 13, 3) <= sys.version_info[:3] <= (3, 13, 5),
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reason="https://github.com/python/cpython/pull/135858",
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)
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def test_filter_alt_messages(self, duplicate_filter_logger, caplog):
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log = duplicate_filter_logger
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log.error("test error message")
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log.error("another error message")
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log.error("test error message")
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log.error("another error message")
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log.error("test error message")
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log.error("test error message")
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log.error("another error message")
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log.error("yet another error message")
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assert len(caplog.records) == 4
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assert caplog.records[0].msg == "test error message"
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assert caplog.records[1].msg == "another error message"
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assert caplog.records[2].msg == "(suppressed 5 repeated lines)"
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assert caplog.records[3].msg == "yet another error message"
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@pytest.fixture
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def pdf_with_invalid_image(outdir):
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# issue 1451
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Name = pikepdf.Name
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pdf = pikepdf.new()
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pdf.add_blank_page()
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pdf.pages[0].Contents = pdf.make_stream(b'612 0 0 612 0 0 cm /Image Do')
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# Create an invalid image object that has both ColorSpace and ImageMask set
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pdf.pages[0].Resources = pikepdf.Dictionary(
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XObject=pdf.make_indirect(
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pikepdf.Dictionary(
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Image=pdf.make_stream(
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b"\xf0\x0f" * 8,
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ColorSpace=Name.DeviceGray,
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BitsPerComponent=1,
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Width=8,
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Height=8,
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ImageMask=True,
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Subtype=Name.Image,
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Type=Name.XObject,
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)
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)
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)
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)
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pdf.save(outdir / 'invalid_image.pdf')
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pdf.save('invalid_image.pdf')
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return outdir / 'invalid_image.pdf'
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@pytest.mark.xfail(
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ghostscript.version() < Version('10.04.0'),
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reason="Older Ghostscript behavior is different",
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)
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def test_recoverable_image_error(pdf_with_invalid_image, outdir, caplog):
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# When stop_on_error is False, we expect Ghostscript to print an error
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# but continue
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rasterize_pdf(
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outdir / 'invalid_image.pdf',
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outdir / 'out.png',
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raster_device='pngmono',
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raster_dpi=Resolution(10, 10),
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stop_on_error=False,
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)
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assert 'Image has both ImageMask and ColorSpace' in caplog.text
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@pytest.mark.xfail(
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ghostscript.version() < Version('10.04.0'),
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reason="Older Ghostscript behavior is different",
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)
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def test_recoverable_image_error_with_stop(pdf_with_invalid_image, outdir, caplog):
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# When stop_on_error is True, Ghostscript will print an error and exit
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# but still produce a viable image. We intercept this case and raise
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# InputFileError because it will contain an image of the whole page minus
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# the image we are rendering.
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with pytest.raises(
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InputFileError, match="Try using --continue-on-soft-render-error"
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):
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rasterize_pdf(
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outdir / 'invalid_image.pdf',
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outdir / 'out.png',
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raster_device='pngmono',
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raster_dpi=Resolution(100, 100),
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stop_on_error=True,
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)
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# out2.png will not be created; if it were it would be blank.
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class TestGs106JpegCorruptionRepair:
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"""Test the Ghostscript 10.6 JPEG corruption repair function."""
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@pytest.fixture
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def create_damaged_pdf(self, resources, outdir):
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"""Create a damaged PDF by truncating JPEG data by 2 bytes."""
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def _create_damaged(source_pdf_name='francais.pdf', truncate_bytes=2):
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source_path = resources / source_pdf_name
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damaged_path = outdir / 'damaged.pdf'
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with pikepdf.open(source_path) as pdf:
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# Find and truncate DCTDecode images
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Name = pikepdf.Name
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damaged_count = 0
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for page in pdf.pages:
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if Name.Resources not in page:
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continue
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resources_dict = page[Name.Resources]
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if Name.XObject not in resources_dict:
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continue
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for key in resources_dict[Name.XObject].keys():
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obj = resources_dict[Name.XObject][key]
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if obj.get(Name.Subtype) != Name.Image:
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continue
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if obj.get(Name.Filter) != Name.DCTDecode:
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continue
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# Truncate the JPEG data
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original_bytes = obj.read_raw_bytes()
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truncated_bytes = original_bytes[:-truncate_bytes]
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obj.write(truncated_bytes, filter=Name.DCTDecode)
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damaged_count += 1
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pdf.save(damaged_path)
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return source_path, damaged_path, damaged_count
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return _create_damaged
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def test_repair_truncated_jpeg(self, create_damaged_pdf, caplog):
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"""Test that truncated JPEG images are repaired."""
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caplog.set_level(logging.DEBUG)
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source_path, damaged_path, damaged_count = create_damaged_pdf()
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assert damaged_count > 0, "Test PDF should have DCTDecode images"
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# Get original image bytes for comparison
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with pikepdf.open(source_path) as pdf:
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Name = pikepdf.Name
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original_bytes_list = []
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for page in pdf.pages:
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if Name.Resources not in page:
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continue
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resources_dict = page[Name.Resources]
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if Name.XObject not in resources_dict:
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continue
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for key in resources_dict[Name.XObject].keys():
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obj = resources_dict[Name.XObject][key]
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if obj.get(Name.Subtype) != Name.Image:
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continue
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if obj.get(Name.Filter) != Name.DCTDecode:
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continue
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original_bytes_list.append(obj.read_raw_bytes())
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# Run the repair function
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repaired = _repair_gs106_jpeg_corruption(source_path, damaged_path)
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assert repaired is True, "Repair should have been performed"
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# Verify the repaired PDF has correct image bytes
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with pikepdf.open(damaged_path) as pdf:
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Name = pikepdf.Name
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repaired_bytes_list = []
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for page in pdf.pages:
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if Name.Resources not in page:
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continue
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resources_dict = page[Name.Resources]
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if Name.XObject not in resources_dict:
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continue
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for key in resources_dict[Name.XObject].keys():
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obj = resources_dict[Name.XObject][key]
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if obj.get(Name.Subtype) != Name.Image:
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continue
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if obj.get(Name.Filter) != Name.DCTDecode:
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continue
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repaired_bytes_list.append(obj.read_raw_bytes())
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assert len(repaired_bytes_list) == len(original_bytes_list)
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for orig, repaired_bytes in zip(original_bytes_list, repaired_bytes_list):
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assert orig == repaired_bytes, "Repaired bytes should match original"
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# Check that error/warning was logged
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assert "JPEG corruption detected" in caplog.text
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def test_no_repair_when_not_truncated(self, resources, outdir, caplog):
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"""Test that no repair is done when images are not truncated."""
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caplog.set_level(logging.DEBUG)
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source_path = resources / 'francais.pdf'
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# Copy source to output (no damage)
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output_path = outdir / 'undamaged.pdf'
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with pikepdf.open(source_path) as pdf:
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pdf.save(output_path)
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# Run the repair function - should not repair anything
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repaired = _repair_gs106_jpeg_corruption(source_path, output_path)
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assert repaired is False, "No repair should have been performed"
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assert "JPEG corruption detected" not in caplog.text
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def test_no_repair_when_truncation_too_large(self, create_damaged_pdf, caplog):
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"""Test that images truncated by more than 15 bytes are not repaired."""
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caplog.set_level(logging.DEBUG)
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source_path, damaged_path, _ = create_damaged_pdf(truncate_bytes=20)
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repaired = _repair_gs106_jpeg_corruption(source_path, damaged_path)
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assert repaired is False, "Should not repair truncation > 15 bytes"
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assert "JPEG corruption detected" not in caplog.text
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