Desktop: Make embedded resources optional (#3094)

* Make embedding resources optional

* Move remaining cef rc to internal module

* Move embedded resources to separate crate

* Review fixup

* Fix

* Fix read

* Add read error

desktop/src/cef/internal/scheme_handler_factory.rs

@@ -0,0 +1,86 @@
+use cef::rc::{Rc, RcImpl};
+use cef::sys::{_cef_scheme_handler_factory_t, cef_base_ref_counted_t, cef_scheme_options_t};
+use cef::{Browser, CefString, Frame, ImplRequest, ImplSchemeHandlerFactory, ImplSchemeRegistrar, Request, ResourceHandler, SchemeRegistrar, WrapSchemeHandlerFactory};
+
+use super::resource_handler::ResourceHandlerImpl;
+use crate::cef::CefEventHandler;
+use crate::cef::consts::{RESOURCE_DOMAIN, RESOURCE_SCHEME};
+
+pub(crate) struct SchemeHandlerFactoryImpl<H: CefEventHandler> {
+	object: *mut RcImpl<_cef_scheme_handler_factory_t, Self>,
+	event_handler: H,
+}
+impl<H: CefEventHandler> SchemeHandlerFactoryImpl<H> {
+	pub(crate) fn new(event_handler: H) -> Self {
+		Self {
+			object: std::ptr::null_mut(),
+			event_handler,
+		}
+	}
+
+	pub(crate) fn register_schemes(registrar: Option<&mut SchemeRegistrar>) {
+		if let Some(registrar) = registrar {
+			let mut scheme_options = 0;
+			scheme_options |= cef_scheme_options_t::CEF_SCHEME_OPTION_STANDARD as i32;
+			scheme_options |= cef_scheme_options_t::CEF_SCHEME_OPTION_FETCH_ENABLED as i32;
+			scheme_options |= cef_scheme_options_t::CEF_SCHEME_OPTION_SECURE as i32;
+			scheme_options |= cef_scheme_options_t::CEF_SCHEME_OPTION_CORS_ENABLED as i32;
+			registrar.add_custom_scheme(Some(&CefString::from(RESOURCE_SCHEME)), scheme_options);
+		}
+	}
+}
+
+impl<H: CefEventHandler> ImplSchemeHandlerFactory for SchemeHandlerFactoryImpl<H> {
+	fn create(&self, _browser: Option<&mut Browser>, _frame: Option<&mut Frame>, scheme_name: Option<&CefString>, request: Option<&mut Request>) -> Option<ResourceHandler> {
+		if let Some(scheme_name) = scheme_name {
+			if scheme_name.to_string() != RESOURCE_SCHEME {
+				return None;
+			}
+			if let Some(request) = request {
+				let url = CefString::from(&request.url()).to_string();
+				let path = url.strip_prefix(&format!("{RESOURCE_SCHEME}://")).unwrap();
+				let domain = path.split('/').next().unwrap_or("");
+				let path = path.strip_prefix(domain).unwrap_or("");
+				let path = path.trim_start_matches('/');
+				return match domain {
+					RESOURCE_DOMAIN => {
+						let resource = self.event_handler.load_resource(path.to_string().into());
+						Some(ResourceHandler::new(ResourceHandlerImpl::new(resource)))
+					}
+					_ => None,
+				};
+			}
+			return None;
+		}
+		None
+	}
+	fn get_raw(&self) -> *mut _cef_scheme_handler_factory_t {
+		self.object.cast()
+	}
+}
+
+impl<H: CefEventHandler> Clone for SchemeHandlerFactoryImpl<H> {
+	fn clone(&self) -> Self {
+		unsafe {
+			let rc_impl = &mut *self.object;
+			rc_impl.interface.add_ref();
+		}
+		Self {
+			object: self.object,
+			event_handler: self.event_handler.clone(),
+		}
+	}
+}
+impl<H: CefEventHandler> Rc for SchemeHandlerFactoryImpl<H> {
+	fn as_base(&self) -> &cef_base_ref_counted_t {
+		unsafe {
+			let base = &*self.object;
+			std::mem::transmute(&base.cef_object)
+		}
+	}
+}
+impl<H: CefEventHandler> WrapSchemeHandlerFactory for SchemeHandlerFactoryImpl<H> {
+	fn wrap_rc(&mut self, object: *mut RcImpl<_cef_scheme_handler_factory_t, Self>) {
+		self.object = object;
+	}
+}