[meld] Make filter headerbar buttons only visible in their related views

[Kai Willadsen <kaiw src gnome org>]

commit 4ac4143b4bad22a5699374a60b7aa7bf9d91f241
Author: Kai Willadsen <kai willadsen gmail com>
Date:   Tue Aug 24 07:18:18 2021 +1000

    Make filter headerbar buttons only visible in their related views
    
    This is a very debatable change. I'm weighing up a desire for the
    header bar to not be too wide (because it gives us a minimum size that
    we can't easily work around) with the desire to have the UI be stable.
    In this case, I've gone with having the available buttons change per
    view, on the basis that there are three text buttons here and they take
    up really quite a lot of horizontal allocation.
    
    Ideally, I think this would be responsive and we'd try to always show
    all three buttons, collapsing down to just the relevant one(s) if
    necessary... but that's really quite a lot more work.

 meld/dirdiff.py  | 5 +++++
 meld/filediff.py | 5 ++++-
 meld/melddoc.py  | 8 ++++++++
 meld/vcview.py   | 4 ++++
 4 files changed, 21 insertions(+), 1 deletion(-)
---
diff --git a/meld/dirdiff.py b/meld/dirdiff.py
index 0d5e1c59..f4a6f805 100644
--- a/meld/dirdiff.py
+++ b/meld/dirdiff.py
@@ -25,6 +25,7 @@ import sys
 from collections import namedtuple
 from decimal import Decimal
 from mmap import ACCESS_COPY, mmap
+from typing import Tuple
 
 from gi.repository import Gdk, Gio, GLib, GObject, Gtk
 
@@ -622,6 +623,10 @@ class DirDiff(Gtk.VBox, tree.TreeviewCommon, MeldDoc):
                 last_column = current_column
             treeview.set_headers_visible(extra_cols)
 
+    def get_filter_visibility(self) -> Tuple[bool, bool, bool]:
+        # TODO: Make text filters available in folder comparison
+        return False, True, False
+
     def on_file_filters_changed(self, app):
         relevant_change = self.create_name_filters()
         if relevant_change:
diff --git a/meld/filediff.py b/meld/filediff.py
index cfbb8f42..b2d72a0a 100644
--- a/meld/filediff.py
+++ b/meld/filediff.py
@@ -18,7 +18,7 @@ import copy
 import functools
 import logging
 import math
-from typing import Optional, Type
+from typing import Optional, Tuple, Type
 
 from gi.repository import Gdk, Gio, GLib, GObject, Gtk, GtkSource
 
@@ -529,6 +529,9 @@ class FileDiff(Gtk.VBox, MeldDoc):
         for sourcemap in self.sourcemap:
             sourcemap.props.compact_view = style == 'compact-sourcemap'
 
+    def get_filter_visibility(self) -> Tuple[bool, bool, bool]:
+        return True, False, False
+
     def on_text_filters_changed(self, app):
         relevant_change = self.create_text_filters()
         if relevant_change:
diff --git a/meld/melddoc.py b/meld/melddoc.py
index 8a3d0b20..47dd647b 100644
--- a/meld/melddoc.py
+++ b/meld/melddoc.py
@@ -209,6 +209,14 @@ class MeldDoc(LabeledObjectMixin, GObject.GObject):
         window.insert_action_group(
             'view', getattr(self, 'view_action_group', None))
 
+        if hasattr(self, "get_filter_visibility"):
+            text, folder, vc = self.get_filter_visibility()
+        else:
+            text, folder, vc = False, False, False
+        window.text_filter_button.set_visible(text)
+        window.folder_filter_button.set_visible(folder)
+        window.vc_filter_button.set_visible(vc)
+
         if hasattr(self, "focus_pane") and self.focus_pane:
             self.scheduler.add_task(self.focus_pane.grab_focus)
 
diff --git a/meld/vcview.py b/meld/vcview.py
index 4a507727..dc180ac0 100644
--- a/meld/vcview.py
+++ b/meld/vcview.py
@@ -22,6 +22,7 @@ import shutil
 import stat
 import sys
 import tempfile
+from typing import Tuple
 
 from gi.repository import Gdk, Gio, GLib, GObject, Gtk, Pango
 
@@ -578,6 +579,9 @@ class VcView(Gtk.VBox, tree.TreeviewCommon, MeldDoc):
             kwargs,
         )
 
+    def get_filter_visibility(self) -> Tuple[bool, bool, bool]:
+        return False, False, True
+
     def action_filter_state_change(self, action, value):
         action.set_state(value)