| # 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 that were excluded if state is False, or the licenses that were |
| included 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 and no excluded licenses).""" |
| # The factor 1000 below is arbitrary, just expected to be much larger |
| # that the number of licenses actually specified. That way the weight |
| # will be negative if the list of licenses contains an excluded license, |
| # but still gives a higher weight to the list with the most included |
| # licenses. |
| alpha_weight = (len(list(filter(include_license, alpha))) - |
| 1000 * (len(list(filter(exclude_license, alpha))) > 0)) |
| beta_weight = (len(list(filter(include_license, beta))) - |
| 1000 * (len(list(filter(exclude_license, beta))) > 0)) |
| 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 |