Add config hash

1 files changed, 48 insertions, 0 deletions

diff --git a/attoconf/lib/config_hash.py b/attoconf/lib/config_hash.py
new file mode 100644
index 0000000..5641558
--- /dev/null
+++ b/attoconf/lib/config_hash.py
@@ -0,0 +1,48 @@
+#   Copyright 2013 Ben Longbons <b.r.longbons@gmail.com>
+#
+#   This file is part of attoconf.
+#
+#   attoconf is free software: you can redistribute it and/or modify
+#   it under the terms of the GNU General Public License as published by
+#   the Free Software Foundation, either version 3 of the License, or
+#   (at your option) any later version.
+#
+#   attoconf is distributed in the hope that it will be useful,
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#   GNU General Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License
+#   along with attoconf.  If not, see <http://www.gnu.org/licenses/>.
+
+from __future__ import print_function, division, absolute_import
+
+from hashlib import md5
+import os
+
+from ..classy import ClassyProject
+
+
+def calc_hash(build):
+    hash = md5()
+    for var, (val, origin), in sorted(build.vars.iteritems()):
+        # origin is not included in the hash
+        hash.update('%s = %s\n' % (var, val))
+    return hash.hexdigest()
+
+
+def add_config_hash(build):
+    print('Generating a hash of config options ...')
+    build.vars['CONFIG_HASH'] = (calc_hash(build), 'special')
+
+
+class ConfigHash(ClassyProject):
+    ''' Post hook add the build hash.
+
+        This should be run before any other post hooks.
+    '''
+    __slots__ = ()
+
+    def post(self):
+        self.checks.append(add_config_hash)
+        super(ConfigHash, self).post()