filediff: Support drag-and-drop directly on to textviews (#177)

kaiw · kaiw · commit 32e39ec7e3ef · 2018-07-22T06:59:24.000+10:00
The behaviour here is hopefully fairly intuitive. If the user drops a
single URI on a file pane, we will load it into that pane. If they drop
several URIs, we'll check to see whether they've dropped the right
number to load all panes, and if so then load them all.

This doesn't handle correctly prelighting of drop zones to e.g., show
the user that they can't drop two files on to a three-way comparison.
This omission is partly due to laziness, but mostly because I don't
think it's a big deal and the drag-motion signal is a bit wild given
that we'd have to coordinate our handling with GtkTextView and also need
to handle the request data dance with drag-data-received.
diff --git a/meld/filediff.py b/meld/filediff.py
@@ -205,6 +205,8 @@ def __init__(self, num_panes):
         for t in self.textview:
             t.connect("focus-in-event", self.on_current_diff_changed)
             t.connect("focus-out-event", self.on_current_diff_changed)
+            t.connect(
+                "drag_data_received", self.on_textview_drag_data_received)
 
         # Bind all overwrite properties together, so that toggling
         # overwrite mode is per-FileDiff.
@@ -768,6 +770,22 @@ def _set_external_action_sensitivity(self):
         except AttributeError:
             pass
 
+    def on_textview_drag_data_received(
+            self, widget, context, x, y, selection_data, info, time):
+        uris = selection_data.get_uris()
+        if uris:
+            gfiles = [Gio.File.new_for_uri(uri) for uri in uris]
+
+            if len(gfiles) == self.num_panes:
+                if self.check_save_modified() == Gtk.ResponseType.OK:
+                    self.set_files(gfiles)
+            elif len(gfiles) == 1:
+                pane = self.textview.index(widget)
+                buffer = self.textbuffer[pane]
+                if self.check_save_modified([buffer]) == Gtk.ResponseType.OK:
+                    self.set_file(pane, gfiles[0])
+            return True
+
     def on_textview_focus_in_event(self, view, event):
         self.focus_pane = view
         self.findbar.textview = view
diff --git a/meld/sourceview.py b/meld/sourceview.py
@@ -147,6 +147,9 @@ def set_show_line_numbers(self, show):
 
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
+
+        self.drag_dest_add_uri_targets()
+
         binding_set = Gtk.binding_set_find('GtkSourceView')
         for key, modifiers in self.replaced_entries:
             Gtk.binding_entry_remove(binding_set, key, modifiers)
