1 files changed, 146 insertions, 0 deletions
diff --git a/morphlib/workspace.py b/morphlib/workspace.py
new file mode 100644
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+++ b/morphlib/workspace.py
@@ -0,0 +1,146 @@
+# Copyright (C) 2013  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.
+#
+# =*= License: GPL-2 =*=
+
+
+'''A module to create, query, and manipulate Morph workspaces.'''
+
+
+import os
+
+import morphlib
+
+
+class WorkspaceDirExists(morphlib.Error):
+
+    def __init__(self, dirname):
+        self.msg = (
+            'can only initialize empty directory as a workspace: %s' %
+            dirname)
+
+
+class NotInWorkspace(morphlib.Error):
+
+    def __init__(self, dirname):
+        self.msg = (
+            "Can't find the workspace directory.\n"
+            "Morph must be built and deployed within the "
+                "system branch checkout within the workspace directory.")
+
+
+class Workspace(object):
+
+    '''A Morph workspace.
+
+    This class should be instantiated with the open() or create()
+    functions in this module.
+
+    '''
+
+    def __init__(self, root_directory):
+        self.root = root_directory
+
+    def get_default_system_branch_directory_name(self, system_branch_name):
+        '''Determine directory where a system branch would be checked out.
+
+        Return the fully qualified pathname to the directory where
+        a system branch would be checked out. The directory may or may
+        not exist already.
+
+        If the system branch is checked out, but into a directory of
+        a different name (which is allowed), that is ignored: this method
+        only computed the default name.
+
+        '''
+
+        return os.path.join(self.root, system_branch_name)
+
+    def create_system_branch_directory(self,
+        root_repository_url, system_branch_name):
+        '''Create a directory for a system branch.
+
+        Return a SystemBranchDirectory object that represents the
+        directory. The directory must not already exist. The directory
+        gets created and initialised (the .morph-system-branch/config
+        file gets created and populated). The root repository of the
+        system branch does NOT get checked out, the caller needs to
+        do that.
+
+        '''
+
+        dirname = self.get_default_system_branch_directory_name(
+            system_branch_name)
+        sb = morphlib.sysbranchdir.create(
+            dirname, root_repository_url, system_branch_name)
+        return sb
+
+    def list_system_branches(self):
+        return (morphlib.sysbranchdir.open(dirname)
+                for dirname in
+                morphlib.util.find_leaves(self.root, '.morph-system-branch'))
+
+
+def open(dirname):
+    '''Open an existing workspace.
+
+    The given directory name may be to a subdirectory of the
+    workspace. This makes it easy to instantiate the Workspace
+    class even when the user invokes Morph in a subdirectory.
+    The workspace MUST exist already, or NotInWorkspace is
+    raised.
+
+    Return a Workspace instance.
+
+    '''
+
+    root = _find_root(dirname)
+    if root is None:
+        raise NotInWorkspace(dirname)
+    return Workspace(root)
+
+
+def create(dirname):
+    '''Create a new workspace.
+
+    The given directory must not be inside an existing workspace.
+    The workspace directory is created, unless it already exists.  If it
+    does exist, it must be empty. Otherwise WorkspaceDirExists is raised.
+
+    '''
+
+    root = _find_root(dirname)
+    if root is not None:
+        raise WorkspaceDirExists(root)
+
+    if os.path.exists(dirname):
+        if os.listdir(dirname):
+            raise WorkspaceDirExists(dirname)
+    else:
+        os.mkdir(dirname)
+    os.mkdir(os.path.join(dirname, '.morph'))
+    return Workspace(dirname)
+
+
+def _find_root(dirname):
+    '''Find the workspace root directory at or above a given directory.'''
+
+    dirname = os.path.normpath(os.path.abspath(dirname))
+    while not os.path.isdir(os.path.join(dirname, '.morph')):
+        if dirname == '/':
+            return None
+        dirname = os.path.dirname(dirname)
+    return dirname
+