Added libbe/upgrade.py to handle upgrading on-disk bugdirs.

1 files changed, 135 insertions, 0 deletions

diff --git a/libbe/upgrade.py b/libbe/upgrade.py
new file mode 100644
index 0000000..a31d6df
--- /dev/null
+++ b/libbe/upgrade.py
@@ -0,0 +1,135 @@
+# Copyright (C) 2009 W. Trevor King <wking@drexel.edu>
+#
+# 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; either version 2 of the License, or
+# (at your option) any later version.
+#
+# 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.
+
+"""
+Handle conversion between the various on-disk images.
+"""
+
+import os, os.path
+import sys
+import doctest
+
+import encoding
+import mapfile
+import rcs
+
+# a list of all past versions
+BUGDIR_DISK_VERSIONS = ["Bugs Everywhere Tree 1 0",
+                        "Bugs Everywhere Directory v2"]
+
+# the current version
+BUGDIR_DISK_VERSION = BUGDIR_DISK_VERSIONS[-1]
+
+class Upgrader (object):
+    "Class for converting "
+    initial_version = None
+    final_version = None
+    def __init__(self, root):
+        self.root = root
+        # use the "None" RCS to ensure proper encoding/decoding and
+        # simplify path construction.
+        self.rcs = rcs.rcs_by_name("None")
+        self.rcs.root(self.root)
+        self.rcs.encoding = encoding.get_encoding()
+
+    def get_path(self, *args):
+        """
+        Return a path relative to .root.
+        """
+        dir = os.path.join(self.root, ".be")
+        if len(args) == 0:
+            return dir
+        assert args[0] in ["version", "settings", "bugs"], str(args)
+        return os.path.join(dir, *args)
+
+    def check_initial_version(self):
+        path = self.get_path("version")
+        version = self.rcs.get_file_contents(path).rstrip("\n")
+        assert version == self.initial_version, version
+
+    def set_version(self):
+        path = self.get_path("version")
+        self.rcs.set_file_contents(path, self.final_version+"\n")
+
+    def upgrade(self):
+        print >> sys.stderr, "upgrading bugdir from '%s' to '%s'" \
+            % (self.initial_version, self.final_version)
+        self.check_initial_version()
+        self.set_version()
+        self._upgrade()
+
+    def _upgrade(self):
+        raise NotImplementedError
+
+class Upgrade_1_0_to_2 (Upgrader):
+    initial_version = "Bugs Everywhere Tree 1 0"
+    final_version = "Bugs Everywhere Directory v2"
+    def _upgrade(self):
+        for bug_uuid in os.listdir(self.get_path("bugs")):
+            c_path = ["bugs", bug_uuid, "comments"]
+            if not os.path.exists(self.get_path(*c_path)):
+                continue # no comments for this bug
+            for comment_uuid in os.listdir(self.get_path(*c_path)):
+                path_list = c_path + [comment_uuid, "values"]
+                path = self.get_path(*path_list)
+                settings = mapfile.map_load(self.rcs, path)
+                if "From" in settings:
+                    settings["Author"] = settings.pop("From")
+                    mapfile.map_save(self.rcs, path, settings)
+
+upgraders = [Upgrade_1_0_to_2]
+upgrade_classes = {}
+for upgrader in upgraders:
+    upgrade_classes[(upgrader.initial_version,upgrader.final_version)]=upgrader
+
+def upgrade(path, current_version,
+            target_version=BUGDIR_DISK_VERSION):
+    """
+    Call the appropriate upgrade function to convert current_version
+    to target_version.  If a direct conversion function does not exist,
+    use consecutive conversion functions.
+    """
+    if current_version not in BUGDIR_DISK_VERSIONS:
+        raise NotImplementedError, \
+            "Cannot handle version '%s' yet." % version
+    if target_version not in BUGDIR_DISK_VERSIONS:
+        raise NotImplementedError, \
+            "Cannot handle version '%s' yet." % version
+
+    if (current_version, target_version) in upgrade_classes:
+        # direct conversion
+        upgrade_class = upgrade_classes[(current_version, target_version)]
+        u = upgrade_class(path)
+        u.upgrade()
+    else:
+        # consecutive single-step conversion
+        i = BUGDIR_DISK_VERSIONS.index(current_version)
+        while True:
+            version_a = BUGDIR_DISK_VERSIONS[i]
+            version_b = BUGDIR_DISK_VERSIONS[i+1]
+            try:
+                upgrade_class = upgrade_classes[(version_a, version_b)]
+            except KeyError:
+                raise NotImplementedError, \
+                    "Cannot convert version '%s' to '%s' yet." \
+                    % (version_a, version_b)
+            u = upgrade_class(path)
+            u.upgrade()
+            if version_b == target_version:
+                break
+            i += 1
+
+suite = doctest.DocTestSuite()