# vi:sts=4:sw=4:et
"""Code for parsing OpenEmbedded license strings"""
import ast
import re
from fnmatch import fnmatchcase as fnmatch
def license_ok(license, dont_want_licenses):
""" Return False if License exist in dont_want_licenses else True """
for dwl in dont_want_licenses:
# If you want to exclude license named generically 'X', we
# surely want to exclude 'X+' as well. In consequence, we
# will exclude a trailing '+' character from LICENSE in
# case INCOMPATIBLE_LICENSE is not a 'X+' license.
lic = license
if not re.search('\+$', dwl):
lic = re.sub('\+', '', license)
if fnmatch(lic, dwl):
return False
return True
class LicenseError(Exception):
pass
class LicenseSyntaxError(LicenseError):
def __init__(self, licensestr, exc):
self.licensestr = licensestr
self.exc = exc
LicenseError.__init__(self)
def __str__(self):
return "error in '%s': %s" % (self.licensestr, self.exc)
class InvalidLicense(LicenseError):
def __init__(self, license):
self.license = license
LicenseError.__init__(self)
def __str__(self):
return "invalid characters in license '%s'" % self.license
license_operator_chars = '&|() '
license_operator = re.compile('([' + license_operator_chars + '])')
license_pattern = re.compile('[a-zA-Z0-9.+_\-]+$')
class LicenseVisitor(ast.NodeVisitor):
"""Get elements based on OpenEmbedded license strings"""
def get_elements(self, licensestr):
new_elements = []
elements = list([x for x in license_operator.split(licensestr) if x.strip()])
for pos, element in enumerate(elements):
if license_pattern.match(element):
if pos > 0 and license_pattern.match(elements[pos-1]):
new_elements.append('&')
element = '"' + element + '"'
elif not license_operator.match(element):
raise InvalidLicense(element)
new_elements.append(element)
return new_elements
"""Syntax tree visitor which can accept elements previously generated with
OpenEmbedded license string"""
def visit_elements(self, elements):
self.visit(ast.parse(' '.join(elements)))
"""Syntax tree visitor which can accept OpenEmbedded license strings"""
def visit_string(self, licensestr):
self.visit_elements(self.get_elements(licensestr))
class FlattenVisitor(LicenseVisitor):
"""Flatten a license tree (parsed from a string) by selecting one of each
set of OR options, in the way the user specifies"""
def __init__(self, choose_licenses):
self.choose_licenses = choose_licenses
self.licenses = []
LicenseVisitor.__init__(self)
def visit_Str(self, node):
self.licenses.append(node.s)
def visit_BinOp(self, node):
if isinstance(node.op, ast.BitOr):
left = FlattenVisitor(self.choose_licenses)
left.visit(node.left)
right = FlattenVisitor(self.choose_licenses)
right.visit(node.right)
selected = self.choose_licenses(left.licenses, right.licenses)
self.licenses.extend(selected)
else:
self.generic_visit(node)
def flattened_licenses(licensestr, choose_licenses):
"""Given a license string and choose_licenses function, return a flat list of licenses"""
flatten = FlattenVisitor(choose_licenses)
try:
flatten.visit_string(licensestr)
except SyntaxError as exc:
raise LicenseSyntaxError(licensestr, exc)
return flatten.licenses
def is_included(licensestr, whitelist=None, blacklist=None):
"""Given a license string and whitelist and blacklist, determine if the
license string matches the whitelist and does not match the blacklist.
Returns a tuple holding the boolean state and a list of the applicable
licenses which were excluded (or None, if the state is True)
"""
def include_license(license):
return any(fnmatch(license, pattern) for pattern in whitelist)
def exclude_license(license):
return any(fnmatch(license, pattern) for pattern in blacklist)
def choose_licenses(alpha, beta):
"""Select the option in an OR which is the 'best' (has the most
included licenses)."""
alpha_weight = len(list(filter(include_license, alpha)))
beta_weight = len(list(filter(include_license, beta)))
if alpha_weight > beta_weight:
return alpha
else:
return beta
if not whitelist:
whitelist = ['*']
if not blacklist:
blacklist = []
licenses = flattened_licenses(licensestr, choose_licenses)
excluded = [lic for lic in licenses if exclude_license(lic)]
included = [lic for lic in licenses if include_license(lic)]
if excluded:
return False, excluded
else:
return True, included
class ManifestVisitor(LicenseVisitor):
"""Walk license tree (parsed from a string) removing the incompatible
licenses specified"""
def __init__(self, dont_want_licenses, canonical_license, d):
self._dont_want_licenses = dont_want_licenses
self._canonical_license = canonical_license
self._d = d
self._operators = []
self.licenses = []
self.licensestr = ''
LicenseVisitor.__init__(self)
def visit(self, node):
if isinstance(node, ast.Str):
lic = node.s
if license_ok(self._canonical_license(self._d, lic),
self._dont_want_licenses) == True:
if self._operators:
ops = []
for op in self._operators:
if op == '[':
ops.append(op)
elif op == ']':
ops.append(op)
else:
if not ops:
ops.append(op)
elif ops[-1] in ['[', ']']:
ops.append(op)
else:
ops[-1] = op
for op in ops:
if op == '[' or op == ']':
self.licensestr += op
elif self.licenses:
self.licensestr += ' ' + op + ' '
self._operators = []
self.licensestr += lic
self.licenses.append(lic)
elif isinstance(node, ast.BitAnd):
self._operators.append("&")
elif isinstance(node, ast.BitOr):
self._operators.append("|")
elif isinstance(node, ast.List):
self._operators.append("[")
elif isinstance(node, ast.Load):
self.licensestr += "]"
self.generic_visit(node)
def manifest_licenses(licensestr, dont_want_licenses, canonical_license, d):
"""Given a license string and dont_want_licenses list,
return license string filtered and a list of licenses"""
manifest = ManifestVisitor(dont_want_licenses, canonical_license, d)
try:
elements = manifest.get_elements(licensestr)
# Replace '()' to '[]' for handle in ast as List and Load types.
elements = ['[' if e == '(' else e for e in elements]
elements = [']' if e == ')' else e for e in elements]
manifest.visit_elements(elements)
except SyntaxError as exc:
raise LicenseSyntaxError(licensestr, exc)
# Replace '[]' to '()' for output correct license.
manifest.licensestr = manifest.licensestr.replace('[', '(').replace(']', ')')
return (manifest.licensestr, manifest.licenses)
class ListVisitor(LicenseVisitor):
"""Record all different licenses found in the license string"""
def __init__(self):
self.licenses = set()
def visit_Str(self, node):
self.licenses.add(node.s)
def list_licenses(licensestr):
"""Simply get a list of all licenses mentioned in a license string.
Binary operators are not applied or taken into account in any way"""
visitor = ListVisitor()
try:
visitor.visit_string(licensestr)
except SyntaxError as exc:
raise LicenseSyntaxError(licensestr, exc)
return visitor.licenses