Massively reorganize and clean up the whole Rust codebase (#478)

* Massively reorganize and clean up the whole Rust codebase

* Additional changes during code review

editor/src/input/input_mapper_message_handler.rs

@@ -0,0 +1,44 @@
+use super::input_mapper::Mapping;
+use super::keyboard::Key;
+use super::InputPreprocessorMessageHandler;
+use crate::message_prelude::*;
+
+use std::fmt::Write;
+
+#[derive(Debug, Default)]
+pub struct InputMapperMessageHandler {
+	mapping: Mapping,
+}
+
+impl InputMapperMessageHandler {
+	pub fn hints(&self, actions: ActionList) -> String {
+		let mut output = String::new();
+		let mut actions = actions
+			.into_iter()
+			.flatten()
+			.filter(|a| !matches!(*a, MessageDiscriminant::Tool(ToolMessageDiscriminant::ActivateTool) | MessageDiscriminant::Global(_)));
+		self.mapping
+			.key_down
+			.iter()
+			.enumerate()
+			.filter_map(|(i, m)| {
+				let ma = m.0.iter().find_map(|m| actions.find_map(|a| (a == m.action.to_discriminant()).then(|| m.action.to_discriminant())));
+
+				ma.map(|a| unsafe { (std::mem::transmute_copy::<usize, Key>(&i), a) })
+			})
+			.for_each(|(k, a)| {
+				let _ = write!(output, "{}: {}, ", k.to_discriminant().local_name(), a.local_name().split('.').last().unwrap());
+			});
+		output.replace("Key", "")
+	}
+}
+
+impl MessageHandler<InputMapperMessage, (&InputPreprocessorMessageHandler, ActionList)> for InputMapperMessageHandler {
+	fn process_action(&mut self, message: InputMapperMessage, data: (&InputPreprocessorMessageHandler, ActionList), responses: &mut VecDeque<Message>) {
+		let (input, actions) = data;
+		if let Some(message) = self.mapping.match_message(message, &input.keyboard, actions) {
+			responses.push_back(message);
+		}
+	}
+	advertise_actions!();
+}