Add a class to manage the staging area for builds

1 files changed, 60 insertions, 0 deletions

diff --git a/morphlib/stagingarea.py b/morphlib/stagingarea.py
new file mode 100644
index 00000000..126d7d91
--- /dev/null
+++ b/morphlib/stagingarea.py
@@ -0,0 +1,60 @@
+# 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 shutil
+import tarfile
+
+
+class StagingArea(object):
+
+    '''Represent the staging area for building software.
+    
+    The build dependencies of what will be built will be installed in the
+    staging area. The staging area may be a dedicated part of the
+    filesystem, used with chroot, or it can be the actual root of the
+    filesystem, which is needed when bootstrap building Baserock. The
+    caller chooses this by providing the root directory of the staging
+    area when the object is created. The directory must already exist.
+    
+    The staging area can also install build artifacts.
+    
+    '''
+    
+    def __init__(self, dirname):
+        self.dirname = dirname
+
+    def install_artifact(self, handle):
+        '''Install a build artifact into the staging area.
+        
+        We access the artifact via an open file handle. For now, we assume
+        the artifact is a tarball.
+        
+        '''
+        
+        tf = tarfile.TarFile(fileobj=handle)
+        tf.extractall(path=self.dirname)
+
+    def remove(self):
+        '''Remove the entire staging area.
+        
+        Do not expect anything with the staging area to work after this
+        method is called. Be careful about calling this method if
+        the filesystem root directory was given as the dirname.
+        
+        '''
+        
+        shutil.rmtree(self.dirname)
+