1 files changed, 116 insertions, 0 deletions
diff --git a/meta/lib/oe/license.py b/meta/lib/oe/license.py
new file mode 100644
index 000000000..173e319cd
--- /dev/null
+++ b/meta/lib/oe/license.py
@@ -0,0 +1,116 @@
+# vi:sts=4:sw=4:et
+"""Code for parsing OpenEmbedded license strings"""
+
+import ast
+import re
+from fnmatch import fnmatchcase as fnmatch
+
+class LicenseError(StandardError):
+    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 = re.compile('([&|() ])')
+license_pattern = re.compile('[a-zA-Z0-9.+_\-]+$')
+
+class LicenseVisitor(ast.NodeVisitor):
+    """Syntax tree visitor which can accept OpenEmbedded license strings"""
+    def visit_string(self, licensestr):
+        new_elements = []
+        elements = filter(lambda x: x.strip(), license_operator.split(licensestr))
+        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)
+
+        self.visit(ast.parse(' '.join(new_elements)))
+
+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(filter(include_license, alpha))
+        beta_weight = len(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 = filter(lambda lic: exclude_license(lic), licenses)
+    included = filter(lambda lic: include_license(lic), licenses)
+    if excluded:
+        return False, excluded
+    else:
+        return True, included