Add config hash

5 files changed, 73 insertions, 24 deletions

diff --git a/attoconf/_version.py b/attoconf/_version.py
index 41d536a..2f23d77 100644
--- a/attoconf/_version.py
+++ b/attoconf/_version.py
@@ -11,7 +11,7 @@ minor = 3
 
 # Incremented if there is a bugfix release.
 # Might not be contiguous.
-patch = 3
+patch = 4
 
 # Reserved for distributors and forks.
 # Contains arbitrary text, but no parentheses or newlines.
diff --git a/attoconf/lib/arches.py b/attoconf/lib/arches.py
index 595b396..007f879 100644
--- a/attoconf/lib/arches.py
+++ b/attoconf/lib/arches.py
@@ -27,14 +27,14 @@ def host(build, HOST):
     if HOST is None:
         BUILD, origin = build.vars['BUILD']
         if origin != 'default':
-            origin = 'derived from BUILD'
+            origin = 'derived'
         build.vars['HOST'] = (BUILD, origin)
 
 def target(build, TARGET):
     if TARGET is None:
         HOST, origin = build.vars['HOST']
         if origin != 'default':
-            origin = 'derived from HOST'
+            origin = 'derived'
         build.vars['TARGET'] = (HOST, origin)
 
 class Arches2(ClassyProject):
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()
diff --git a/attoconf/lib/install.py b/attoconf/lib/install.py
index a807666..498b13b 100644
--- a/attoconf/lib/install.py
+++ b/attoconf/lib/install.py
@@ -39,63 +39,63 @@ def exec_prefix(build, EPREFIX):
     if EPREFIX is None:
         PREFIX, origin = build.vars['PREFIX']
         if origin != 'default':
-            origin = 'derived from PREFIX'
+            origin = 'derived'
         build.vars['EPREFIX'] = (PREFIX, origin)
 
 def bindir(build, DIR):
     if DIR is None:
         EPREFIX, origin = build.vars['EPREFIX']
         if origin != 'default':
-            origin = 'derived from EPREFIX'
+            origin = 'derived'
         build.vars['BINDIR'] = (os.path.join(EPREFIX, 'bin'), origin)
 
 def sbindir(build, DIR):
     if DIR is None:
         EPREFIX, origin = build.vars['EPREFIX']
         if origin != 'default':
-            origin = 'derived from EPREFIX'
+            origin = 'derived'
         build.vars['SBINDIR'] = (os.path.join(EPREFIX, 'sbin'), origin)
 
 def libexecdir(build, DIR):
     if DIR is None:
         EPREFIX, origin = build.vars['EPREFIX']
         if origin != 'default':
-            origin = 'derived from EPREFIX'
+            origin = 'derived'
         build.vars['LIBEXECDIR'] = (os.path.join(EPREFIX, 'libexec'), origin)
 
 def sysconfdir(build, DIR):
     if DIR is None:
         PREFIX, origin = build.vars['PREFIX']
         if origin != 'default':
-            origin = 'derived from PREFIX'
+            origin = 'derived'
         build.vars['SYSCONFDIR'] = (os.path.join(PREFIX, 'etc'), origin)
 
 def sharedstatedir(build, DIR):
     if DIR is None:
         PREFIX, origin = build.vars['PREFIX']
         if origin != 'default':
-            origin = 'derived from PREFIX'
+            origin = 'derived'
         build.vars['SHAREDSTATEDIR'] = (os.path.join(PREFIX, 'com'), origin)
 
 def localstatedir(build, DIR):
     if DIR is None:
         PREFIX, origin = build.vars['PREFIX']
         if origin != 'default':
-            origin = 'derived from PREFIX'
+            origin = 'derived'
         build.vars['LOCALSTATEDIR'] = (os.path.join(PREFIX, 'var'), origin)
 
 def libdir(build, DIR):
     if DIR is None:
         EPREFIX, origin = build.vars['EPREFIX']
         if origin != 'default':
-            origin = 'derived from EPREFIX'
+            origin = 'derived'
         build.vars['LIBDIR'] = (os.path.join(EPREFIX, 'lib'), origin)
 
 def includedir(build, DIR):
     if DIR is None:
         PREFIX, origin = build.vars['PREFIX']
         if origin != 'default':
-            origin = 'derived from PREFIX'
+            origin = 'derived'
         build.vars['INCLUDEDIR'] = (os.path.join(PREFIX, 'include'), origin)
 
 def oldincludedir(build, DIR):
@@ -105,14 +105,14 @@ def datarootdir(build, DIR):
     if DIR is None:
         PREFIX, origin = build.vars['PREFIX']
         if origin != 'default':
-            origin = 'derived from PREFIX'
+            origin = 'derived'
         build.vars['DATAROOTDIR'] = (os.path.join(PREFIX, 'share'), origin)
 
 def datadir(build, DIR):
     if DIR is None:
         DATAROOTDIR, origin = build.vars['DATAROOTDIR']
         if origin != 'default':
-            origin = 'derived from DATAROOTDIR'
+            origin = 'derived'
         build.vars['DATADIR'] = (DATAROOTDIR, origin)
 
 def packagedatadir(build, DIR):
@@ -120,28 +120,28 @@ def packagedatadir(build, DIR):
         DATADIR, origin = build.vars['DATADIR']
         PACKAGE, prigin = build.vars['PACKAGE']
         if origin != 'default' or prigin != 'default':
-            origin = 'derived from DATADIR and PACKAGE'
+            origin = 'derived'
         build.vars['DATADIR'] = (os.path.join(DATADIR, PACKAGE), origin)
 
 def infodir(build, DIR):
     if DIR is None:
         DATAROOTDIR, origin = build.vars['DATAROOTDIR']
         if origin != 'default':
-            origin = 'derived from DATAROOTDIR'
+            origin = 'derived'
         build.vars['INFODIR'] = (os.path.join(DATAROOTDIR, 'info'), origin)
 
 def localedir(build, DIR):
     if DIR is None:
         DATAROOTDIR, origin = build.vars['DATAROOTDIR']
         if origin != 'default':
-            origin = 'derived from DATAROOTDIR'
+            origin = 'derived'
         build.vars['LOCALEDIR'] = (os.path.join(DATAROOTDIR, 'locale'), origin)
 
 def mandir(build, DIR):
     if DIR is None:
         DATAROOTDIR, origin = build.vars['DATAROOTDIR']
         if origin != 'default':
-            origin = 'derived from DATAROOTDIR'
+            origin = 'derived'
         build.vars['MANDIR'] = (os.path.join(DATAROOTDIR, 'man'), origin)
 
 def docdir(build, DIR):
@@ -149,35 +149,35 @@ def docdir(build, DIR):
         DATAROOTDIR, origin = build.vars['DATAROOTDIR']
         PACKAGE, origin2 = build.vars['PACKAGE']
         if origin != 'default' or origin2 != 'default':
-            origin = 'derived from DATAROOTDIR and PACKAGE'
+            origin = 'derived'
         build.vars['DOCDIR'] = (os.path.join(DATAROOTDIR, 'doc', PACKAGE), origin)
 
 def htmldir(build, DIR):
     if DIR is None:
         DOCDIR, origin = build.vars['DOCDIR']
         if origin != 'default':
-            origin = 'derived from DOCDIR'
+            origin = 'derived'
         build.vars['HTMLDIR'] = (DOCDIR, origin)
 
 def dvidir(build, DIR):
     if DIR is None:
         DOCDIR, origin = build.vars['DOCDIR']
         if origin != 'default':
-            origin = 'derived from DOCDIR'
+            origin = 'derived'
         build.vars['DVIDIR'] = (DOCDIR, origin)
 
 def pdfdir(build, DIR):
     if DIR is None:
         DOCDIR, origin = build.vars['DOCDIR']
         if origin != 'default':
-            origin = 'derived from DOCDIR'
+            origin = 'derived'
         build.vars['PDFDIR'] = (DOCDIR, origin)
 
 def psdir(build, DIR):
     if DIR is None:
         DOCDIR, origin = build.vars['DOCDIR']
         if origin != 'default':
-            origin = 'derived from DOCDIR'
+            origin = 'derived'
         build.vars['PSDIR'] = (DOCDIR, origin)
 
 
diff --git a/demo-project/configure b/demo-project/configure
index a3e49ee..c26e557 100755
--- a/demo-project/configure
+++ b/demo-project/configure
@@ -28,10 +28,11 @@ require_version(0, 2)
 from attoconf.classy import add_slots
 from attoconf.lib.c import C
 from attoconf.lib.install import Install
+from attoconf.lib.config_hash import ConfigHash
 from attoconf.lib.make import Make
 
 @add_slots
-class Configuration(C, Install, Make):
+class Configuration(C, Install, ConfigHash, Make):
     # usually you'll only have vars, features, and packages
     # the rest should only be inherited
     def __init__(self, srcdir):