room-history: Do not offer to copy the thumbnail until it is loaded

src/session/view/content/room_history/item_row.rs

@@ -52,6 +52,32 @@ mod imp {
         fn class_init(klass: &mut Self::Class) {
             klass.set_css_name("room-history-row");
             klass.set_accessible_role(gtk::AccessibleRole::ListItem);
+
+            klass.install_action(
+                "room-history-row.enable-copy-image",
+                Some(&bool::static_variant_type()),
+                |obj, _, param| {
+                    let enable = param
+                        .and_then(glib::Variant::get::<bool>)
+                        .expect("The parameter should be a boolean");
+                    let imp = obj.imp();
+
+                    let Some(action_group) = imp.action_group.borrow().clone() else {
+                        error!("Could not change state of copy-image action: no action group");
+                        return;
+                    };
+                    let Some(action) = action_group.lookup_action("copy-image") else {
+                        error!("Could not change state of copy-image action: action not found");
+                        return;
+                    };
+                    tracing::debug!("Action: {action:?}");
+                    let Some(action) = action.downcast_ref::<gio::SimpleAction>() else {
+                        error!("Could not change state of copy-image action: not a GSimpleAction");
+                        return;
+                    };
+                    action.set_enabled(enable);
+                },
+            );
         }
     }
 

src/session/view/content/room_history/message_row/visual_media.rs

@@ -7,7 +7,7 @@ use gtk::{
 };
 use matrix_sdk::Client;
 use ruma::api::client::media::get_content_thumbnail::v3::Method;
-use tracing::warn;
+use tracing::{error, warn};
 
 use super::ContentFormat;
 use crate::{
@@ -324,6 +324,11 @@ mod imp {
 
         /// Build the content for the image in the given media message.
         async fn build_image(&self, media_message: &VisualMediaMessage, client: Client) {
+            // Disable the copy-image action while the image is loading.
+            if matches!(media_message, VisualMediaMessage::Image(_)) {
+                self.enable_copy_image_action(false);
+            }
+
             let scale_factor = self.obj().scale_factor();
 
             let settings = ThumbnailSettings {
@@ -364,6 +369,25 @@ mod imp {
             }
 
             self.set_state(LoadingState::Ready);
+
+            // Enable the copy-image action now that the image is loaded.
+            if matches!(media_message, VisualMediaMessage::Image(_)) {
+                self.enable_copy_image_action(true);
+            }
+        }
+
+        /// Enable or disable the context menu action to copy the image.
+        fn enable_copy_image_action(&self, enable: bool) {
+            if self
+                .obj()
+                .activate_action(
+                    "room-history-row.enable-copy-image",
+                    Some(&enable.to_variant()),
+                )
+                .is_err()
+            {
+                error!("Could not change state of copy-image action: `room-history-row.enable-copy-image` action not found");
+            }
         }
 
         /// Build the content for the video in the given media message.