Add portage.dep.extract_affecting_use()

2 files changed, 173 insertions, 0 deletions

diff --git a/pym/portage/dep/__init__.py b/pym/portage/dep/__init__.py
index 1b89afec0..f15b8a2d9 100644
--- a/pym/portage/dep/__init__.py
+++ b/pym/portage/dep/__init__.py
@@ -1458,3 +1458,106 @@ def check_required_use(required_use, use, iuse):
 			_("malformed syntax: '%s'") % required_use)
 
 	return (False not in stack[0])
+
+def extract_affecting_use(mystr, atom):
+	"""
+	Take a dep string and an atom and return the use flags
+	that decide if the given atom is in effect.
+
+	Example usage:
+		>>> extract_use_cond('sasl? ( dev-libs/cyrus-sasl ) \
+			!minimal? ( cxx? ( dev-libs/cyrus-sasl ) )', 'dev-libs/cyrus-sasl')
+		(['sasl', 'minimal', 'cxx'])
+
+	@param dep: The dependency string
+	@type mystr: String
+	@param atom: The atom to get into effect
+	@type atom: String
+	@rtype: Tuple of two lists of strings
+	@return: List of use flags that need to be enabled, List of use flag that need to be disabled
+	"""
+	mysplit = mystr.split()
+	level = 0
+	stack = [[]]
+	need_bracket = False
+	affecting_use = set()
+	atom_seen = False
+
+	def flag(conditional):
+		if conditional[0] == "!":
+			flag = conditional[1:-1]
+		else:
+			flag = conditional[:-1]
+
+		if not flag:
+			raise portage.exception.InvalidDependString(
+				_("malformed syntax: '%s'") % mystr)
+
+		return flag
+
+	for token in mysplit:
+		if token == "(":
+			need_bracket = False
+			stack.append([])
+			level += 1
+		elif token == ")":
+			if need_bracket:
+				raise portage.exception.InvalidDependString(
+					_("malformed syntax: '%s'") % mystr)
+			if level > 0:
+				level -= 1
+				l = stack.pop()
+
+				if l:
+					if not stack[level] or (stack[level][-1] != "||" and not stack[level][-1][-1] == "?"):
+						#Optimize: ( ( ... ) ) -> ( ... )
+						stack[level].extend(l)
+					elif len(l) == 1 and stack[level][-1] == "||":
+						#Optimize: || ( A ) -> A
+						stack[level].pop()
+						stack[level].extend(l)
+					elif len(l) == 2 and (l[0] == "||" or l[0][-1] == "?") and stack[level][-1] in (l[0], "||"):
+						#Optimize: 	|| ( || ( ... ) ) -> || ( ... )
+						#			foo? ( foo? ( ... ) ) -> foo? ( ... )
+						#			|| ( foo? ( ... ) ) -> foo? ( ... )
+						stack[level].pop()
+						stack[level].extend(l)
+						if l[0][-1] == "?":
+							affecting_use.add(flag(l[0]))
+					else:
+						if stack[level] and stack[level][-1][-1] == "?":
+							affecting_use.add(flag(stack[level][-1]))
+						stack[level].append(l)
+				else:
+					if stack[level] and (stack[level][-1] == "||" or stack[level][-1][-1] == "?"):
+						stack[level].pop()
+			else:
+				raise portage.exception.InvalidDependString(
+					_("malformed syntax: '%s'") % mystr)
+		elif token == "||":
+			if need_bracket:
+				raise portage.exception.InvalidDependString(
+					_("malformed syntax: '%s'") % mystr)
+			need_bracket = True
+			stack[level].append(token)
+		else:
+			if need_bracket or "(" in token or ")" in token or "|" in token:
+				raise portage.exception.InvalidDependString(
+					_("malformed syntax: '%s'") % mystr)
+
+			if token[-1] == "?":
+				need_bracket = True
+				stack[level].append(token)
+			elif token == atom:
+				atom_seen = True
+				stack[level].append(token)
+
+	if level != 0 or need_bracket:
+		raise portage.exception.InvalidDependString(
+			_("malformed syntax: '%s'") % mystr)
+
+	if not atom_seen:
+		raise portage.exception.IncorrectParameter(
+			_("extract_affecting_use: atom '%s' not in dep string: '%s'") % (atom, mystr))
+
+	return affecting_use
diff --git a/pym/portage/tests/dep/testExtractAffectingUSE.py b/pym/portage/tests/dep/testExtractAffectingUSE.py
new file mode 100644
index 000000000..ba904b927
--- /dev/null
+++ b/pym/portage/tests/dep/testExtractAffectingUSE.py
@@ -0,0 +1,70 @@
+# Copyright 2010 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+
+from portage.tests import TestCase
+from portage.dep import extract_affecting_use
+from portage.exception import InvalidDependString, IncorrectParameter
+
+class TestExtractAffectingUSE(TestCase):
+
+	def testExtractAffectingUSE(self):
+		test_cases = (
+			("a? ( A ) !b? ( B ) !c? ( C ) d? ( D )", "A", ("a",)),
+			("a? ( A ) !b? ( B ) !c? ( C ) d? ( D )", "B", ("b",)),
+			("a? ( A ) !b? ( B ) !c? ( C ) d? ( D )", "C", ("c",)),
+			("a? ( A ) !b? ( B ) !c? ( C ) d? ( D )", "D", ("d",)),
+			
+			("a? ( b? ( AB ) )", "AB", ("a", "b")),
+			("a? ( b? ( c? ( ABC ) ) )", "ABC", ("a", "b", "c")),
+
+			("a? ( A b? ( c? ( ABC ) AB ) )", "A", ("a",)),
+			("a? ( A b? ( c? ( ABC ) AB ) )", "AB", ("a", "b")),
+			("a? ( A b? ( c? ( ABC ) AB ) )", "ABC", ("a", "b", "c")),
+			("a? ( A b? ( c? ( ABC ) AB ) ) X", "X", []),
+			("X a? ( A b? ( c? ( ABC ) AB ) )", "X", []),
+
+			("ab? ( || ( A B ) )", "A", ("ab",)),
+			("!ab? ( || ( A B ) )", "B", ("ab",)),
+			("ab? ( || ( A || ( b? ( || ( B C ) ) ) ) )", "A", ("ab",)),
+			("ab? ( || ( A || ( b? ( || ( B C ) ) ) ) )", "B", ("ab", "b")),
+			("ab? ( || ( A || ( b? ( || ( B C ) ) ) ) )", "C", ("ab", "b")),
+
+			("( ab? ( || ( ( A ) || ( b? ( ( ( || ( B ( C ) ) ) ) ) ) ) ) )", "A", ("ab",)),
+			("( ab? ( || ( ( A ) || ( b? ( ( ( || ( B ( C ) ) ) ) ) ) ) ) )", "B", ("ab", "b")),
+			("( ab? ( || ( ( A ) || ( b? ( ( ( || ( B ( C ) ) ) ) ) ) ) ) )", "C", ("ab", "b")),
+		)
+
+		test_cases_xfail = (
+			("? ( A )", "A"),
+			("!? ( A )", "A"),
+			("( A", "A"),
+			("A )", "A"),
+			
+			("||( A B )", "A"),
+			("|| (A B )", "A"),
+			("|| ( A B)", "A"),
+			("|| ( A B", "A"),
+			("|| A B )", "A"),
+			("|| A B", "A"),
+			("|| ( A B ) )", "A"),
+			("|| || B C", "A"),
+			("|| ( A B || )", "A"),
+			("a? A", "A"),
+			("( || ( || || ( A ) foo? ( B ) ) )", "A"),
+			("( || ( || bar? ( A ) foo? ( B ) ) )", "A"),
+
+			("a? ( A )", "B"),
+		)
+
+		for dep, atom, expected in test_cases:
+			expected = set(expected)
+			result = extract_affecting_use(dep, atom)
+			fail_msg = "dep: " + dep + ", atom: " + atom + ", got: " + \
+				" ".join(sorted(result)) + ", expected: " + " ".join(sorted(expected))
+			self.assertEqual(result, expected, fail_msg)
+
+		for dep, atom in test_cases_xfail:
+			fail_msg = "dep: " + dep + ", atom: " + atom + ", got: " + \
+				" ".join(sorted(result)) + ", expected: " + " ".join(sorted(expected))
+			self.assertRaisesMsg(fail_msg, \
+				(InvalidDependString, IncorrectParameter), extract_affecting_use, dep, atom)