# Copyright (C) 2025 Siemens
#
# SPDX-License-Identifier: MIT
from collections.abc import Iterable
from functools import cached_property
from debian.copyright import (
Copyright as DebCopyright,
License,
MachineReadableFormatError,
NotMachineReadableError,
)
from license_expression import LicenseExpression, Licensing, get_spdx_licensing
import logging
from pathlib import Path
import re
logger = logging.getLogger(__name__)
# well-known list of expressions conversions, see
# https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/#license-specification
WELL_KNOWN_EXPRESSIONS = {
"AGPL-1": "AGPL-1.0-only",
"AGPL-1+": "AGPL-1.0-or-later",
"AGPL-3": "AGPL-3.0-only",
"AGPL-3+": "AGPL-3.0-or-later",
"Apache-1": "Apache-1.0",
"Apache-2": "Apache-2.0",
"Artistic": "Artistic-1.0",
"Artistic-1": "Artistic-1.0",
"Artistic-2": "Artistic-2.0",
"BSD-2": "BSD-2-Clause",
"BSD-3": "BSD-3-Clause",
"BSD-4": "BSD-4-Clause",
"BSL": "BSL-1.0",
"BSL-1": "BSL-1.0",
"CC-BY": "CC-BY-1.0",
"CC-BY-1": "CC-BY-1.0",
"CC-BY-2": "CC-BY-2.0",
"CC-BY-3": "CC-BY-3.0",
"CC-BY-4": "CC-BY-4.0",
"CC-BY-NC": "CC-BY-NC-1.0",
"CC-BY-NC-1": "CC-BY-NC-1.0",
"CC-BY-NC-2": "CC-BY-NC-2.0",
"CC-BY-NC-3": "CC-BY-NC-3.0",
"CC-BY-NC-4": "CC-BY-NC-4.0",
"CC-BY-NC-ND": "CC-BY-NC-ND-1.0",
"CC-BY-NC-ND-1": "CC-BY-NC-ND-1.0",
"CC-BY-NC-ND-2": "CC-BY-NC-ND-2.0",
"CC-BY-NC-ND-3": "CC-BY-NC-ND-3.0",
"CC-BY-NC-ND-4": "CC-BY-NC-ND-4.0",
"CC-BY-NC-SA": "CC-BY-NC-SA-1.0",
"CC-BY-NC-SA-1": "CC-BY-NC-SA-1.0",
"CC-BY-NC-SA-2": "CC-BY-NC-SA-2.0",
"CC-BY-NC-SA-3": "CC-BY-NC-SA-3.0",
"CC-BY-NC-SA-4": "CC-BY-NC-SA-4.0",
"CC-BY-SA": "CC-BY-SA-1.0",
"CC-BY-SA-1": "CC-BY-SA-1.0",
"CC-BY-SA-2": "CC-BY-SA-2.0",
"CC-BY-SA-3": "CC-BY-SA-3.0",
"CC-BY-SA-4": "CC-BY-SA-4.0",
"CC0": "CC0-1.0",
"CC0-1": "CC0-1.0",
"CDDL": "CDDL-1.0",
"CDDL-1": "CDDL-1.0",
"CPL": "CPL-1.0",
"CPL-1": "CPL-1.0",
"EFL": "EFL-1.0",
"EFL-1": "EFL-1.0",
"EFL-2": "EFL-2.0",
"EPL": "EPL-1.0",
"EPL-1": "EPL-1.0",
"EPL-2": "EPL-2.0",
"Expat": "MIT",
"GFDL": "GFDL-1.1-only",
"GFDL+": "GFDL-1.1-or-later",
"GFDL-1.1": "GFDL-1.1-only",
"GFDL-1.1+": "GFDL-1.1-or-later",
"GFDL-1.2": "GFDL-1.2-only",
"GFDL-1.2+": "GFDL-1.2-or-later",
"GFDL-1.3": "GFDL-1.3-only",
"GFDL-1.3+": "GFDL-1.3-or-later",
"GFDL-NIV": "GFDL-1.1-no-invariants-only",
"GFDL-NIV+": "GFDL-1.1-no-invariants-or-later",
"GFDL-NIV-1.1": "GFDL-1.1-no-invariants-only",
"GFDL-NIV-1.1+": "GFDL-1.1-no-invariants-or-later",
"GFDL-NIV-1.2": "GFDL-1.2-no-invariants-only",
"GFDL-NIV-1.2+": "GFDL-1.2-no-invariants-or-later",
"GFDL-NIV-1.3": "GFDL-1.3-no-invariants-only",
"GFDL-NIV-1.3+": "GFDL-1.3-no-invariants-or-later",
"GPL": "GPL-1.0-only",
"GPL+": "GPL-1.0-or-later",
"GPL-1": "GPL-1.0-only",
"GPL-1+": "GPL-1.0-or-later",
"GPL-2": "GPL-2.0-only",
"GPL-2+": "GPL-2.0-or-later",
"GPL-3": "GPL-3.0-only",
"GPL-3+": "GPL-3.0-or-later",
"GPL3+": "GPL-3.0-or-later",
"LGPL": "LGPL-1.0-only",
"LGPL+": "LGPL-1.0-or-later",
"LGPL-1": "LGPL-1.0-only",
"LGPL-1+": "LGPL-1.0-or-later",
"LGPL-2": "LGPL-2.0-only",
"LGPL-2+": "LGPL-2.0-or-later",
"LGPL-3": "LGPL-3.0-only",
"LGPL-3+": "LGPL-3.0-or-later",
"LPGL-2.1": "LGPL-2.1-only",
"LPGL-2.1+": "LGPL-2.1-or-later",
"LPPL": "LPPL-1.0",
"LPPL-1": "LPPL-1.0",
"MPL": "MPL-1.0",
"MPL-1": "MPL-1.0",
"MPL-2": "MPL-2.0",
"PSF-2": "PSF-2.0",
"Perl": "Artistic-1.0-Perl",
"Python": "Python-2.0",
"QPL": "QPL-1.0",
"QPL-1": "QPL-1.0",
"RubyLicense": "Ruby",
"SIL-1": "OFL-1.0",
"SIL-1.1": "OFL-1.1",
"SIL-OFL-1": "OFL-1.0",
"SIL-OFL-1.1": "OFL-1.1",
"Zope": "ZPL-1.0",
"Zope-1": "ZPL-1.0",
"Zope-2": "ZPL-2.0",
}
# Debian exception names are free-form. Only map complete license names with
# exceptions whose license and exception texts have been verified.
WELL_KNOWN_EXCEPTIONS = {
"GPL-3+ with Bison exception": "GPL-3.0-or-later WITH Bison-exception-2.2",
"GPL-3+ with Bison-2.2 exception": "GPL-3.0-or-later WITH Bison-exception-2.2",
"GPL-2 with Linux-syscall-note exception": "GPL-2.0-only WITH Linux-syscall-note",
"GPL-3+ with texinfo exception": "GPL-3.0-or-later WITH Texinfo-exception",
"GPL-3.0-or-later-WITH-Autoconf-exception-macro": (
"GPL-3.0-or-later WITH Autoconf-exception-macro"
),
"BSD-3-clause-Cambridge with BINARY LIBRARY-LIKE PACKAGES exception": (
"BSD-3-Clause WITH PCRE2-exception"
),
"GPL-3+-WITH-BISON-EXCEPTION": "GPL-3.0-or-later WITH Bison-exception-2.2",
}
_EXCEPTIONS = {name.lower(): expression for name, expression in WELL_KNOWN_EXCEPTIONS.items()}
_EXCEPTIONS_RE = re.compile(
r"(?<![\w+.-])(?:{})(?![\w+.-])".format(
"|".join(re.escape(name) for name in sorted(WELL_KNOWN_EXCEPTIONS, key=len, reverse=True))
),
re.IGNORECASE,
)
[docs]
class UnknownLicenseError(Exception):
"""License is unknown to the SPDX standard."""
pass
[docs]
class Copyright(DebCopyright):
"""Copyright information for a source package."""
def __init__(self, path: Path):
if not path.is_file():
raise FileNotFoundError(path)
self._path = path
@classmethod
def _convert_expression(cls, line: str) -> str:
"""Convert a Debian license expression to the equivalent SPDX syntax."""
line = _EXCEPTIONS_RE.sub(lambda match: _EXCEPTIONS[match.group().lower()], line)
# in the Debian copyright format ',' are used for disambiguation
# that means (with 'and' having precedence over 'or'):
# A or B and C <=> A or (B and C)
# A or B, and C <=> (A or B) and C
# for more information see
# https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/#license-specification
tokens = line.split(" ")
indices = []
for i, token in enumerate(tokens):
if token.endswith(","):
tokens[i] = token[:-1]
indices.append(i)
# keep track of inserted tokens
inserted = 0
for i in range(len(indices)):
# the opening brace can be inserted always at the beginning
tokens.insert(0, "(")
# and the closing brace after the token that had the comma
tokens.insert(indices[i] + inserted + 2, ")")
inserted += 2
return " ".join(tokens)
[docs]
def licenses(self) -> Iterable[License]:
"""Return all licenses found in the copyright file."""
with open(self._path, encoding="utf-8") as f:
try:
licenses = list(self._parse_licenses(DebCopyright(f)))
except NotMachineReadableError:
logger.debug(f"non-machine-readable copyright file: {self._path}")
return
except (MachineReadableFormatError, ValueError):
logger.debug(f"bad format for machine-readable copyright file: {self._path}")
return
yield from licenses
def _parse_licenses(self, copyright: DebCopyright) -> Iterable[License]:
lic = copyright.header.license
if lic:
yield lic
for paragraph in copyright.all_files_paragraphs():
yield paragraph.license
@cached_property
def _spdx_license_expressions(self) -> list[LicenseExpression]:
"""Return all licenses as SPDX license expressions."""
licensing = get_spdx_licensing()
exprs = []
for lic in self.licenses():
if not lic.synopsis:
raise UnknownLicenseError("only license text is available")
expr = self._convert_expression(lic.synopsis)
spdx_lic = licensing.parse(expr)
unknown_keys = licensing.unknown_license_keys(spdx_lic)
# TODO: how do we handle `public-domain` licensing?
if len(unknown_keys) > 0:
# unknown keys in the license expression, try to replace them
# with well-known representations
unreplaced = []
for unknown_key in unknown_keys:
replacement = WELL_KNOWN_EXPRESSIONS.get(unknown_key)
if replacement:
expr = expr.replace(unknown_key, replacement)
else:
unreplaced.append(unknown_key)
if len(unreplaced) > 0:
s = ", ".join(unreplaced)
raise UnknownLicenseError(f"unknown license keys: {s}")
exprs.append(licensing.parse(expr, validate=True))
else:
exprs.append(spdx_lic)
if not len(exprs):
raise UnknownLicenseError("no license information available")
return exprs
def spdx_license_expressions(self) -> Iterable[LicenseExpression]:
yield from self._spdx_license_expressions
[docs]
class CopyrightDirectory:
"""Directory of Debian copyright information."""
def __init__(self, path: Path):
self.copyright_root = path
@classmethod
def for_rootdir(cls, root: Path) -> "CopyrightDirectory":
return CopyrightDirectory(root / "usr/share/doc")
[docs]
def copyright(self, bin_pkg) -> Copyright:
"""Get the copyright information for a binary package."""
copyright_path = self.copyright_root / bin_pkg.name / "copyright"
return Copyright(copyright_path)