[meld] dirdiff: Add an ISO-format version of our mtime column (#188)

[Kai Willadsen <kaiw src gnome org>]

commit 85d62c46e7b2b1dba82895afd214af95c78ae010
Author: Kai Willadsen <kai willadsen gmail com>
Date:   Sun Jan 9 07:49:49 2022 +1000

    dirdiff: Add an ISO-format version of our mtime column (#188)

 meld/dirdiff.py          | 25 ++++++++++++++++++++++++-
 meld/preferences.py      |  8 ++++++--
 meld/ui/cellrenderers.py | 15 ++++++++++++++-
 3 files changed, 44 insertions(+), 4 deletions(-)
---
diff --git a/meld/dirdiff.py b/meld/dirdiff.py
index 30e01822..4bc7da25 100644
--- a/meld/dirdiff.py
+++ b/meld/dirdiff.py
@@ -45,6 +45,7 @@ from meld.ui.cellrenderers import (
     CellRendererByteSize,
     CellRendererDate,
     CellRendererFileMode,
+    CellRendererISODate,
 )
 from meld.ui.emblemcellrenderer import EmblemCellRenderer
 from meld.ui.util import map_widgets_into_lists
@@ -569,6 +570,14 @@ class DirDiff(Gtk.VBox, tree.TreeviewCommon, MeldDoc):
             column.set_attributes(rentext, timestamp=col_index(COL_TIME, i))
             self.treeview[i].append_column(column)
             self.columns_dict[i]["modification time"] = column
+            # Create ISO-format date-time CellRenderer
+            column = Gtk.TreeViewColumn(_("Modification time (ISO)"))
+            column.set_resizable(True)
+            rentext = CellRendererISODate()
+            column.pack_start(rentext, True)
+            column.set_attributes(rentext, timestamp=col_index(COL_TIME, i))
+            self.treeview[i].append_column(column)
+            self.columns_dict[i]["iso-time"] = column
             # Create permissions CellRenderer
             column = Gtk.TreeViewColumn(_("Permissions"))
             column.set_resizable(True)
@@ -627,11 +636,22 @@ class DirDiff(Gtk.VBox, tree.TreeviewCommon, MeldDoc):
             _files_same, comparison_args=comparison_args)
         self.refresh()
 
-    def update_treeview_columns(self, settings, key):
+    def update_treeview_columns(
+        self, settings: Gio.Settings, key: str,
+    ) -> None:
         """Update the visibility and order of columns"""
+
         columns = settings.get_value(key)
         have_extra_columns = any(visible for name, visible in columns)
 
+        # Check for columns missing from the settings, special-casing
+        # the always-present name column
+        configured_columns = [name for name, visible in columns] + ["name"]
+        missing_columns = [
+            c for c in self.columns_dict[0].keys()
+            if c not in configured_columns
+        ]
+
         for i, treeview in enumerate(self.treeview):
             last_column = treeview.get_column(0)
             for column_name, visible in columns:
@@ -644,6 +664,9 @@ class DirDiff(Gtk.VBox, tree.TreeviewCommon, MeldDoc):
                 treeview.move_column_after(current_column, last_column)
                 last_column = current_column
 
+            for column_name in missing_columns:
+                self.columns_dict[i][column_name].set_visible(False)
+
             treeview.set_headers_visible(have_extra_columns)
 
     def get_filter_visibility(self) -> Tuple[bool, bool, bool]:
diff --git a/meld/preferences.py b/meld/preferences.py
index 8139a65f..67e99ad2 100644
--- a/meld/preferences.py
+++ b/meld/preferences.py
@@ -131,6 +131,7 @@ class ColumnList(Gtk.VBox, EditableListWidget):
     available_columns = {
         "size": _("Size"),
         "modification time": _("Modification time"),
+        "iso-time": _("Modification time (ISO)"),
         "permissions": _("Permissions"),
     }
 
@@ -158,10 +159,13 @@ class ColumnList(Gtk.VBox, EditableListWidget):
             column_order[column_name] = sort_key
 
         columns = [
-            (column_vis.get(name, True), name, label)
+            (column_vis.get(name, False), name, label)
             for name, label in self.available_columns.items()
         ]
-        columns = sorted(columns, key=lambda c: column_order.get(c[1], 0))
+        columns = sorted(
+            columns,
+            key=lambda c: column_order.get(c[1], len(self.available_columns)),
+        )
 
         for visibility, name, label in columns:
             self.model.append([visibility, name, label])
diff --git a/meld/ui/cellrenderers.py b/meld/ui/cellrenderers.py
index 24824894..488dd1ce 100644
--- a/meld/ui/cellrenderers.py
+++ b/meld/ui/cellrenderers.py
@@ -26,6 +26,9 @@ class CellRendererDate(Gtk.CellRendererText):
     MIN_TIMESTAMP = -2147483648
     DATETIME_FORMAT = "%a %d %b %Y %H:%M:%S"
 
+    def _format_datetime(self, dt: datetime.datetime) -> str:
+        return dt.strftime(self.DATETIME_FORMAT)
+
     def get_timestamp(self):
         return getattr(self, '_datetime', self.MIN_TIMESTAMP)
 
@@ -37,7 +40,7 @@ class CellRendererDate(Gtk.CellRendererText):
         else:
             try:
                 mod_datetime = datetime.datetime.fromtimestamp(value)
-                time_str = mod_datetime.strftime(self.DATETIME_FORMAT)
+                time_str = self._format_datetime(mod_datetime)
             except Exception:
                 time_str = ''
         self.props.markup = time_str
@@ -51,6 +54,16 @@ class CellRendererDate(Gtk.CellRendererText):
     )
 
 
+class CellRendererISODate(CellRendererDate):
+
+    __gtype_name__ = "CellRendererISODate"
+
+    def _format_datetime(self, dt: datetime.datetime) -> str:
+        # Limit our ISO display to seconds (i.e., no milli or
+        # microseconds) for usability
+        return dt.isoformat(timespec="seconds")
+
+
 class CellRendererByteSize(Gtk.CellRendererText):
 
     __gtype_name__ = "CellRendererByteSize"