When regenerating USE_EXPAND in config.setcpv(), improve performance by

using regular expression instead of str.startswith().

svn path=/main/trunk/; revision=9890

1 files changed, 14 insertions, 7 deletions

diff --git a/pym/portage/__init__.py b/pym/portage/__init__.py
index 5c712a472..59270ac58 100644
--- a/pym/portage/__init__.py
+++ b/pym/portage/__init__.py
@@ -2035,8 +2035,12 @@ class config(object):
 		for var in use_expand:
 			prefix = var.lower() + "_"
 			prefix_len = len(prefix)
-			expand_flags = set([ x[prefix_len:] for x in use \
-				if x.startswith(prefix) ])
+			prefix_re = re.compile(r'^(%s)(.*)' % prefix)
+			expand_flags = set()
+			for x in use:
+				m = prefix_re.match(x)
+				if m is not None:
+					expand_flags.add(m.group(2))
 			var_split = self.get(var, "").split()
 			# Preserve the order of var_split because it can matter for things
 			# like LINGUAS.
@@ -2047,15 +2051,18 @@ class config(object):
 				var_split = [ x for x in var_split if x != "*" ]
 			has_iuse = set()
 			for x in iuse_implicit:
-				if x.startswith(prefix):
-					has_iuse.add(x[prefix_len:])
+				m = prefix_re.match(x)
+				if m is not None:
+					has_iuse.add(m.group(2))
 			if has_wildcard:
 				# * means to enable everything in IUSE that's not masked
 				if has_iuse:
 					for x in iuse_implicit:
-						if x.startswith(prefix) and x not in self.usemask:
-							suffix = x[prefix_len:]
-							var_split.append(suffix)
+						if x in self.usemask:
+							continue
+						m = prefix_re.match(x)
+						if m is not None:
+							var_split.append(m.group(2))
 							use.add(x)
 				else:
 					# If there is a wildcard and no matching flags in IUSE then