114 lines
3.8 KiB
Python
114 lines
3.8 KiB
Python
# vi:sts=4:sw=4:et
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"""Code for parsing OpenEmbedded license strings"""
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import ast
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import re
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from fnmatch import fnmatchcase as fnmatch
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class LicenseError(StandardError):
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pass
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class LicenseSyntaxError(LicenseError):
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def __init__(self, licensestr, exc):
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self.licensestr = licensestr
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self.exc = exc
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LicenseError.__init__(self)
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def __str__(self):
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return "error in '%s': %s" % (self.licensestr, self.exc)
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class InvalidLicense(LicenseError):
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def __init__(self, license):
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self.license = license
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LicenseError.__init__(self)
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def __str__(self):
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return "invalid characters in license '%s'" % self.license
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license_operator = re.compile('([&|() ])')
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license_pattern = re.compile('[a-zA-Z0-9.+_\-]+$')
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class LicenseVisitor(ast.NodeVisitor):
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"""Syntax tree visitor which can accept OpenEmbedded license strings"""
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def visit_string(self, licensestr):
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new_elements = []
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elements = filter(lambda x: x.strip(), license_operator.split(licensestr))
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for pos, element in enumerate(elements):
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if license_pattern.match(element):
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if pos > 0 and license_pattern.match(elements[pos-1]):
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new_elements.append('&')
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element = '"' + element + '"'
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elif not license_operator.match(element):
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raise InvalidLicense(element)
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new_elements.append(element)
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self.visit(ast.parse(' '.join(new_elements)))
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class FlattenVisitor(LicenseVisitor):
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"""Flatten a license tree (parsed from a string) by selecting one of each
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set of OR options, in the way the user specifies"""
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def __init__(self, choose_licenses):
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self.choose_licenses = choose_licenses
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self.licenses = []
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LicenseVisitor.__init__(self)
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def visit_Str(self, node):
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self.licenses.append(node.s)
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def visit_BinOp(self, node):
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if isinstance(node.op, ast.BitOr):
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left = FlattenVisitor(self.choose_licenses)
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left.visit(node.left)
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right = FlattenVisitor(self.choose_licenses)
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right.visit(node.right)
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selected = self.choose_licenses(left.licenses, right.licenses)
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self.licenses.extend(selected)
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else:
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self.generic_visit(node)
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def flattened_licenses(licensestr, choose_licenses):
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"""Given a license string and choose_licenses function, return a flat list of licenses"""
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flatten = FlattenVisitor(choose_licenses)
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try:
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flatten.visit_string(licensestr)
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except SyntaxError as exc:
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raise LicenseSyntaxError(licensestr, exc)
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return flatten.licenses
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def is_included(licensestr, whitelist=None, blacklist=None):
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"""Given a license string and whitelist and blacklist, determine if the
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license string matches the whitelist and does not match the blacklist.
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Returns a tuple holding the boolean state and a list of the applicable
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licenses which were excluded (or None, if the state is True)
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"""
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def include_license(license):
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return (any(fnmatch(license, pattern) for pattern in whitelist) and not
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any(fnmatch(license, pattern) for pattern in blacklist))
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def choose_licenses(alpha, beta):
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"""Select the option in an OR which is the 'best' (has the most
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included licenses)."""
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alpha_weight = len(filter(include_license, alpha))
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beta_weight = len(filter(include_license, beta))
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if alpha_weight > beta_weight:
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return alpha
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else:
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return beta
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if not whitelist:
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whitelist = ['*']
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if not blacklist:
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blacklist = []
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licenses = flattened_licenses(licensestr, choose_licenses)
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excluded = filter(lambda lic: not include_license(lic), licenses)
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if excluded:
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return False, excluded
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else:
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return True, None
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