[fractal/fractal-next] error: Add 'Error' object for handling error

[Julian Sparber <jsparber src gnome org>]

commit ffad9696bf06da5c495bb78c9ec859597931a069
Author: Julian Sparber <julian sparber net>
Date:   Thu May 27 12:38:19 2021 +0200

    error: Add 'Error' object for handling error

 po/POTFILES.in  |  1 +
 src/error.rs    | 63 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/main.rs     |  2 ++
 src/meson.build |  1 +
 4 files changed, 67 insertions(+)
---
diff --git a/po/POTFILES.in b/po/POTFILES.in
index 89fe36a3..bcbe1a39 100644
--- a/po/POTFILES.in
+++ b/po/POTFILES.in
@@ -33,6 +33,7 @@ src/components/label_with_widgets.rs
 src/components/mod.rs
 src/components/spinner_button.rs
 src/components/pill.rs
+src/error.rs
 src/login.rs
 src/main.rs
 src/secret.rs
diff --git a/src/error.rs b/src/error.rs
new file mode 100644
index 00000000..c4d3e192
--- /dev/null
+++ b/src/error.rs
@@ -0,0 +1,63 @@
+use gtk::{glib, subclass::prelude::*};
+
+use matrix_sdk::Error as MatrixError;
+
+mod imp {
+    use super::*;
+    use once_cell::sync::OnceCell;
+    use std::cell::RefCell;
+
+    #[derive(Default)]
+    pub struct Error {
+        pub matrix_error: OnceCell<MatrixError>,
+        pub widget_builder:
+            RefCell<Option<Box<dyn Fn(&super::Error) -> Option<gtk::Widget> + 'static>>>,
+    }
+
+    #[glib::object_subclass]
+    impl ObjectSubclass for Error {
+        const NAME: &'static str = "Error";
+        type Type = super::Error;
+        type ParentType = glib::Object;
+    }
+
+    impl ObjectImpl for Error {}
+}
+
+glib::wrapper! {
+    pub struct Error(ObjectSubclass<imp::Error>);
+}
+
+/// An `Error` that can be shown in the UI
+impl Error {
+    pub fn new<F: Fn(&Self) -> Option<gtk::Widget> + 'static>(error: MatrixError, f: F) -> Self {
+        let obj: Self = glib::Object::new(&[]).expect("Failed to create Error");
+        obj.set_matrix_error(error);
+        obj.set_widget_builder(f);
+        obj
+    }
+
+    fn set_matrix_error(&self, error: MatrixError) {
+        let priv_ = imp::Error::from_instance(&self);
+        priv_.matrix_error.set(error).unwrap()
+    }
+
+    pub fn matrix_error(&self) -> &MatrixError {
+        let priv_ = imp::Error::from_instance(&self);
+        priv_.matrix_error.get().unwrap()
+    }
+
+    /// Set a function that builds the widget used to display this error in the UI
+    pub fn set_widget_builder<F: Fn(&Self) -> Option<gtk::Widget> + 'static>(&self, f: F) {
+        let priv_ = imp::Error::from_instance(&self);
+        priv_.widget_builder.replace(Some(Box::new(f)));
+    }
+
+    /// Produces a widget via the function set in `Self::set_widget_builder()`
+    pub fn widget(&self) -> Option<gtk::Widget> {
+        let priv_ = imp::Error::from_instance(&self);
+        let widget_builder = priv_.widget_builder.borrow();
+        let widget_builder = widget_builder.as_ref()?;
+        widget_builder(self)
+    }
+}
diff --git a/src/main.rs b/src/main.rs
index ea741574..d837c266 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -7,6 +7,7 @@ mod application;
 mod config;
 
 mod components;
+mod error;
 mod login;
 mod secret;
 mod session;
@@ -14,6 +15,7 @@ mod utils;
 mod window;
 
 use self::application::Application;
+use self::error::Error;
 use self::login::Login;
 use self::session::Session;
 use self::window::Window;
diff --git a/src/meson.build b/src/meson.build
index 2fd00aca..b2c8fd8c 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -26,6 +26,7 @@ sources = files(
   'components/pill.rs',
   'components/spinner_button.rs',
   'config.rs',
+  'error.rs',
   'main.rs',
   'window.rs',
   'login.rs',