[meld] ui.cellrenderers: New helper for small cellrenderer conveniences

[Kai Willadsen <kaiw src gnome org>]

commit 821bb753d56532ccd541eae3eb44f0778492b6dd
Author: Kai Willadsen <kai willadsen gmail com>
Date:   Sun Oct 23 12:49:10 2016 +1000

    ui.cellrenderers: New helper for small cellrenderer conveniences

 meld/dirdiff.py          | 13 +++++--------
 meld/ui/cellrenderers.py | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+), 8 deletions(-)
---
diff --git a/meld/dirdiff.py b/meld/dirdiff.py
index 61581cdc..da86c31c 100644
--- a/meld/dirdiff.py
+++ b/meld/dirdiff.py
@@ -18,7 +18,6 @@
 
 import collections
 import copy
-import datetime
 import errno
 import functools
 import os
@@ -46,6 +45,7 @@ from meld.misc import all_same
 from meld.recent import RecentType
 from meld.settings import bind_settings, meldsettings, settings
 from meld.treehelpers import refocus_deleted_path
+from meld.ui.cellrenderers import CellRendererDate
 
 
 ################################################################################
@@ -210,7 +210,7 @@ COL_EMBLEM, COL_SIZE, COL_TIME, COL_PERMS, COL_END = \
 
 class DirDiffTreeStore(tree.DiffTreeStore):
     def __init__(self, ntree):
-        tree.DiffTreeStore.__init__(self, ntree, [str, str, str, str])
+        tree.DiffTreeStore.__init__(self, ntree, [str, str, object, str])
 
 
 class CanonicalListing(object):
@@ -398,9 +398,9 @@ class DirDiff(melddoc.MeldDoc, gnomeglade.Component):
             # Create date-time CellRenderer
             column = Gtk.TreeViewColumn(_("Modification time"))
             column.set_resizable(True)
-            rentext = Gtk.CellRendererText()
+            rentext = CellRendererDate()
             column.pack_start(rentext, True)
-            column.set_attributes(rentext, markup=col_index(COL_TIME, i))
+            column.set_attributes(rentext, timestamp=col_index(COL_TIME, i))
             self.treeview[i].append_column(column)
             self.columns_dict[i]["modification time"] = column
             # Create permissions CellRenderer
@@ -1311,11 +1311,8 @@ class DirDiff(melddoc.MeldDoc, gnomeglade.Component):
                     it, self.model.column_index(COL_EMBLEM, j), emblem)
                 one_isdir[j] = isdir
 
-                # A DateCellRenderer would be nicer, but potentially very slow
                 TIME = self.model.column_index(COL_TIME, j)
-                mod_datetime = datetime.datetime.fromtimestamp(mod_times[j])
-                time_str = mod_datetime.strftime("%a %d %b %Y %H:%M:%S")
-                self.model.set_value(it, TIME, time_str)
+                self.model.set_value(it, TIME, mod_times[j])
 
                 def natural_size(bytes):
                     suffixes = (
diff --git a/meld/ui/cellrenderers.py b/meld/ui/cellrenderers.py
new file mode 100644
index 00000000..ccd9f901
--- /dev/null
+++ b/meld/ui/cellrenderers.py
@@ -0,0 +1,48 @@
+# Copyright (C) 2016 Kai Willadsen <kai willadsen gmail com>
+#
+# 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, see <http://www.gnu.org/licenses/>.
+
+import datetime
+
+from gi.repository import GObject
+from gi.repository import Gtk
+
+
+class CellRendererDate(Gtk.CellRendererText):
+
+    __gtype_name__ = "CellRendererDate"
+
+    DATETIME_FORMAT = "%a %d %b %Y %H:%M:%S"
+
+    def get_timestamp(self):
+        return getattr(self, '_datetime', None)
+
+    def set_timestamp(self, value):
+        if value == self.get_timestamp():
+            return
+        if value is None:
+            time_str = ''
+        else:
+            mod_datetime = datetime.datetime.fromtimestamp(value)
+            time_str = mod_datetime.strftime(self.DATETIME_FORMAT)
+        self.props.markup = time_str
+        self._datetime = value
+
+    timestamp = GObject.property(
+        type=object,
+        nick="Unix timestamp to display",
+        getter=get_timestamp,
+        setter=set_timestamp,
+    )
+    )