1 files changed, 90 insertions, 0 deletions
diff --git a/morphlib/morphologyfactory.py b/morphlib/morphologyfactory.py
new file mode 100644
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+++ b/morphlib/morphologyfactory.py
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+# Copyright (C) 2012-2014  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 os
+
+import morphlib
+import cliapp
+
+
+class MorphologyFactoryError(cliapp.AppException):
+    pass
+
+
+class MorphologyNotFoundError(MorphologyFactoryError):
+    def __init__(self, filename):
+        MorphologyFactoryError.__init__(
+            self, "Couldn't find morphology: %s" % filename)
+
+
+class NotcachedError(MorphologyFactoryError):
+    def __init__(self, repo_name):
+        MorphologyFactoryError.__init__(
+            self, "Repository %s is not cached locally and there is no "
+                  "remote cache specified" % repo_name)
+
+
+class MorphologyFactory(object):
+
+    '''A way of creating morphologies which will provide a default'''
+
+    def __init__(self, local_repo_cache, remote_repo_cache=None, app=None):
+        self._lrc = local_repo_cache
+        self._rrc = remote_repo_cache
+        self._app = app
+
+    def status(self, *args, **kwargs):  # pragma: no cover
+        if self._app is not None:
+            self._app.status(*args, **kwargs)
+
+    def get_morphology(self, reponame, sha1, filename):
+        morph_name = os.path.splitext(os.path.basename(filename))[0]
+        loader = morphlib.morphloader.MorphologyLoader()
+        if self._lrc.has_repo(reponame):
+            self.status(msg="Looking for %s in local repo cache" % filename,
+                        chatty=True)
+            try:
+                repo = self._lrc.get_repo(reponame)
+                morph = loader.load_from_string(repo.cat(sha1, filename))
+            except IOError:
+                morph = None
+                file_list = repo.ls_tree(sha1)
+        elif self._rrc is not None:
+            self.status(msg="Retrieving %(reponame)s %(sha1)s %(filename)s"
+                        " from the remote git cache.",
+                        reponame=reponame, sha1=sha1, filename=filename,
+                        chatty=True)
+            try:
+                text = self._rrc.cat_file(reponame, sha1, filename)
+                morph = loader.load_from_string(text)
+            except morphlib.remoterepocache.CatFileError:
+                morph = None
+                file_list = self._rrc.ls_tree(reponame, sha1)
+        else:
+            raise NotcachedError(reponame)
+
+        if morph is None:
+            self.status(msg="File %s doesn't exist: attempting to infer "
+                            "chunk morph from repo's build system"
+                        % filename, chatty=True)
+            bs = morphlib.buildsystem.detect_build_system(file_list)
+            if bs is None:
+                raise MorphologyNotFoundError(filename)
+            morph = bs.get_morphology(morph_name)
+            loader.validate(morph)
+            loader.set_commands(morph)
+            loader.set_defaults(morph)
+        return morph