Add portage.util._ctypes module, for bug #439584.

1 files changed, 47 insertions, 0 deletions

diff --git a/pym/portage/util/_ctypes.py b/pym/portage/util/_ctypes.py
new file mode 100644
index 000000000..4e5aa2a6b
--- /dev/null
+++ b/pym/portage/util/_ctypes.py
@@ -0,0 +1,47 @@
+# Copyright 2012 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+
+try:
+	import ctypes
+	import ctypes.util
+except ImportError:
+	ctypes = None
+else:
+	try:
+		ctypes.cdll
+	except AttributeError:
+		ctypes = None
+
+_library_names = {}
+
+def find_library(name):
+	"""
+	Calls ctype.util.find_library() if the ctypes module is available,
+	and otherwise returns None. Results are cached for future invocations.
+	"""
+	filename = _library_names.get(name)
+	if filename is None:
+		if ctypes is not None:
+			filename = ctypes.util.find_library(name)
+			if filename is None:
+				filename = False
+			_library_names[name] = filename
+
+	if filename is False:
+		return None
+	return filename
+
+_library_handles = {}
+
+def LoadLibrary(name):
+	"""
+	Calls ctypes.cdll.LoadLibrary(name) if the ctypes module is available,
+	and otherwise returns None. Results are cached for future invocations.
+	"""
+	handle = _library_handles.get(name)
+
+	if handle is None and ctypes is not None:
+		handle = ctypes.cdll.LoadLibrary(name)
+		_library_handles[name] = handle
+
+	return handle