pisi hs --takeback <operation no>

Takes back the system to the state after the given operation finished.

Taking back to a snapshot and taking real action (installing and removing packages)
is not done yet. But we are there already. :)

pisi/api.py

@@ -39,6 +39,7 @@ import pisi.operations.delta
 import pisi.operations.remove
 import pisi.operations.upgrade
 import pisi.operations.install
+import pisi.operations.history
 import pisi.operations.helper
 import pisi.operations.emerge
 import pisi.operations.build
@@ -282,6 +283,17 @@ def install(packages, reinstall=False, ignore_file_conflicts=False):
     else:
         return pisi.operations.install.install_pkg_names(packages, reinstall)
 
+def takeback(operation):
+    """
+    Takes the system back to the state after the given operation no from the pisi history.
+    @param operation: operation number -> integer
+    """
+    
+    historydb = pisi.db.historydb.HistoryDB()
+    historydb.create_history("takeback")
+
+    pisi.operations.history.takeback(operation)
+
 def snapshot():
     """
     Takes snapshot of the system packages. The snapshot is only a record of which packages are currently

pisi/cli/history.py

@@ -48,10 +48,15 @@ Lists previous operations."""
                          help=_("Output only the last n operations"))
         group.add_option("-s", "--snapshot", action="store_true", default=False,
                          help=_("Take snapshot of the current system"))
+        group.add_option("-t", "--takeback", action="store", type="int", default=1,
+                         help=_("Takeback to the state after the given operation finished"))
 
     def take_snapshot(self):
         pisi.api.snapshot()
 
+    def takeback(self, operation):
+        pisi.api.takeback(operation)
+
     def print_history(self):
         for operation in self.historydb.get_last(ctx.get_option('last')):
             print _("Operation #%d: %s") % (operation.no, operation.type)
@@ -62,7 +67,7 @@ Lists previous operations."""
                 print _("    * There are %d packages in this snapshot.") % len(operation.packages)
             else:
                 for pkg in operation.packages:
-                    print "    *", pkg
+                    print "    *",  pkg
             print
 
     def run(self):
@@ -70,5 +75,7 @@ Lists previous operations."""
 
         if ctx.get_option('snapshot'):
             self.take_snapshot()
+        elif ctx.get_option('takeback'):
+            self.takeback(ctx.get_option('takeback'))
         else:
             self.print_history()

pisi/history.py

@@ -76,7 +76,7 @@ class History(xmlfile.XmlFile):
 
     def create(self, operation):
 
-        if operation not in ["upgrade", "remove", "emerge", "install", "snapshot"]:
+        if operation not in ["upgrade", "remove", "emerge", "install", "snapshot", "takeback"]:
             raise Exception("Unknown package operation")
         
         self.histfile = "%s_%s.xml" % (self._get_latest(), operation)

pisi/operations/history.py

@@ -0,0 +1,57 @@
+# -*- coding: utf-8 -*-
+#
+# Copyright (C) 2008, TUBITAK/UEKAE
+#
+# 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.
+#
+# Please read the COPYING file.
+
+import gettext
+__trans = gettext.translation("pisi", fallback=True)
+_ = __trans.ugettext
+
+import pisi.context as ctx
+import pisi.util
+import pisi.db
+
+def __listactions(actions):
+    beinstalled = []
+    beremoved = []
+
+    for pkg in actions:
+        action, version = actions[pkg]
+        if action == "install":
+            beinstalled.append("%s-%s" % (pkg, version))
+        else:
+            beremoved.append("%s" % pkg)
+
+    return beinstalled, beremoved
+
+def takeback(operation):
+
+    historydb = pisi.db.historydb.HistoryDB()
+    actions = {}
+
+    for operation in historydb.get_till_operation(operation):
+        if operation == "snapshot":
+            pass
+
+        for pkg in operation.packages:
+            if pkg.operation in ["upgrade", "downgrade", "remove"]:
+                actions[pkg.name] = ("install", pkg.before)
+            if pkg.operation == "install":
+                actions[pkg.name] = ("remove", None)
+
+    beinstalled, beremoved = __listactions(actions)
+
+    if beinstalled:
+        ctx.ui.info(_("Following packages will be installed:\n") + pisi.util.strlist(beinstalled))
+
+    if beremoved:
+        ctx.ui.info(_("Following packages will be removed:\n") + pisi.util.strlist(beremoved))
+
+    if (beremoved or beinstalled) and not ctx.ui.confirm(_('Do you want to continue?')):
+        return