license: split license parsing into oe.license

In addition to moving this functionality to oe.license, makes the string
preparation more picky before passing it off to the ast compilation. This
ensures that LICENSE entries like 'GPL/BSD' are seen as invalid (due to the
presence of the unsupported '/').

(From OE-Core rev: 20d4068045c76e9dc2aff0c152dd02d6a109c9dd)

Signed-off-by: Christopher Larson <kergoth@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/lib/oe/license.py

@@ -0,0 +1,32 @@
+# vi:sts=4:sw=4:et
+"""Code for parsing OpenEmbedded license strings"""
+
+import ast
+import re
+
+class InvalidLicense(StandardError):
+    def __init__(self, license):
+        self.license = license
+        StandardError.__init__(self)
+
+    def __str__(self):
+        return "invalid 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)))

meta/lib/oe/tests/test_license.py

@@ -0,0 +1,38 @@
+import unittest
+import oe.license
+
+class SeenVisitor(oe.license.LicenseVisitor):
+    def __init__(self):
+        self.seen = []
+        oe.license.LicenseVisitor.__init__(self)
+
+    def visit_Str(self, node):
+        self.seen.append(node.s)
+
+class TestSingleLicense(unittest.TestCase):
+    licenses = [
+        "GPLv2",
+        "LGPL-2.0",
+        "Artistic",
+        "MIT",
+        "GPLv3+",
+        "FOO_BAR",
+    ]
+    invalid_licenses = ["GPL/BSD"]
+
+    @staticmethod
+    def parse(licensestr):
+        visitor = SeenVisitor()
+        visitor.visit_string(licensestr)
+        return visitor.seen
+
+    def test_single_licenses(self):
+        for license in self.licenses:
+            licenses = self.parse(license)
+            self.assertListEqual(licenses, [license])
+
+    def test_invalid_licenses(self):
+        for license in self.invalid_licenses:
+            with self.assertRaises(oe.license.InvalidLicense) as cm:
+                self.parse(license)
+            self.assertEqual(cm.exception.license, license)