add morphology factory

1 files changed, 63 insertions, 0 deletions

diff --git a/morphlib/morphologyfactory.py b/morphlib/morphologyfactory.py
new file mode 100644
index 00000000..5e3bf7f2
--- /dev/null
+++ b/morphlib/morphologyfactory.py
@@ -0,0 +1,63 @@
+#!/usr/bin/python
+#
+# Copyright (C) 2012  Codethink Limited
+#
+# This program 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; version 2 of the License.
+#
+# This program 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 this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+import morphlib
+import cliapp
+
+class MorphologyFactoryError(cliapp.AppException):
+    pass
+
+class AutodetectError(MorphologyFactoryError):
+    def __init__(self, repo_name, ref):
+        MorphologyFactoryError.__init__(self, 
+                "Failed to determine the build system of repo %s at "
+                "ref %s" % (repo_name, ref))
+
+class MorphologyFactory(object):
+    '''An way of creating morphologies which will provide a default'''
+
+    def __init__(self, local_repo_cache, remote_repo_cache):
+        self._lrc = local_repo_cache
+        self._rrc = remote_repo_cache
+
+    def get_morphology(self, reponame, sha1, filename):
+        try:
+            text = self._cat_text(reponame, sha1, filename)
+        except:
+            text = self._autodetect_text(reponame, sha1, filename)
+        return morphlib.morph2.Morphology(text)
+
+    def _cat_text(self, reponame, sha1, filename):
+        if self._lrc.has_repo(reponame):
+            repo = self._lrc.get_repo(reponame)
+            return repo.cat(sha1, filename)
+        else:
+            return self._rrc.cat_file(reponame, sha1, filename)
+
+    def _autodetect_text(self, reponame, sha1, filename):
+        if self._lrc.has_repo(reponame):
+            repo = self._lrc.get_repo(reponame)
+            files = repo.list_files(sha1)
+        else:
+            files = self._rrc.list_files(reponame, sha1)
+        bs = morphlib.buildsystem.detect_build_system(lambda x: x in files)
+        if bs is None:
+            raise AutodetectError(reponame, sha1)
+        assert filename.endswith('.morph')
+        morph_name = filename[:-len('.morph')]
+        morph_text = bs.get_morphology_text(morph_name)
+        return morph_text