feat(iOS): added custom URL schemes handling in the AppDelegate class (#969)

* feat(iOS): added custom URL schemes handling in the `AppDelegate` class

Until now, only ["associated
domains"](https://developer.apple.com/documentation/xcode/supporting-associated-domains)
were handled, using the `application_continue` function, that implements [this
Swift method from the `UIApplicationDelegate`
class](https://developer.apple.com/documentation/uikit/uiapplicationdelegate/1623072-application).

For [custom URL
schemes](https://developer.apple.com/documentation/xcode/defining-a-custom-url-scheme-for-your-app),
I added a new `application_open_url` function that matches the signature of
[this other Swift
method](https://developer.apple.com/documentation/uikit/uiapplicationdelegate/1623112-application).

Most of the code of the pre-existing `application_continue` has been moved
into a separate `handle_deep_link` function so the new `application_open_url`
can call it as well.

I believe using the same `Event::Opened` event is appropriate in both
situations. Since the scheme is part of the URL, a listener can differentiate
between them if needed.

**Tauri:** since we are emitting the same `Event::Opened` event, this change
works automatically with the ["Deep Linking"
plugin](https://v2.tauri.app/plugin/deep-linking/) without further
modifications.

Custom URL schemes in mobile apps are essential, for example,
when dealing with OAuth redirect URLs.

* Update .changes/ios-custom-url-schemes.md

Co-authored-by: Jason Tsai <[email protected]>

---------

Co-authored-by: Jason Tsai <[email protected]>

Author: CampioneDev

.changes/ios-custom-url-schemes.md

@@ -0,0 +1,5 @@
+---
+"tao": patch
+---
+
+On iOS, implement `application:openURL:options:` to handle custom URL schemes.

src/platform_impl/ios/view.rs

@@ -555,7 +555,40 @@ pub fn create_delegate_class() {
     YES
   }
 
+  fn handle_deep_link(url: id) {
+    unsafe {
+      let absolute_url: id = msg_send![url, absoluteString];
+      let bytes = {
+        let bytes: *const c_char = msg_send![absolute_url, UTF8String];
+        bytes as *const u8
+      };
+
+      // 4 represents utf8 encoding
+      let len = msg_send![absolute_url, lengthOfBytesUsingEncoding: 4];
+      let bytes = std::slice::from_raw_parts(bytes, len);
+
+      let url = url::Url::parse(std::str::from_utf8(bytes).unwrap()).unwrap();
+
+      app_state::handle_nonuser_event(EventWrapper::StaticEvent(Event::Opened { urls: vec![url] }));
+    }
+  }
+
+  // custom URL schemes
+  // https://developer.apple.com/documentation/xcode/defining-a-custom-url-scheme-for-your-app
+  extern "C" fn application_open_url(
+    _self: &mut Object,
+    _cmd: Sel,
+    _app: id,
+    url: id,
+    _options: id,
+  ) -> BOOL {
+    handle_deep_link(url);
+
+    YES
+  }
+
   // universal links
+  // https://developer.apple.com/documentation/xcode/supporting-universal-links-in-your-app
   extern "C" fn application_continue(
     _: &mut Object,
     _: Sel,
@@ -568,19 +601,8 @@ pub fn create_delegate_class() {
       if webpage_url == nil {
         return NO;
       }
-      let absolute_url: id = msg_send![webpage_url, absoluteString];
-      let bytes = {
-        let bytes: *const c_char = msg_send![absolute_url, UTF8String];
-        bytes as *const u8
-      };
 
-      // 4 represents utf8 encoding
-      let len = msg_send![absolute_url, lengthOfBytesUsingEncoding: 4];
-      let bytes = std::slice::from_raw_parts(bytes, len);
-
-      let url = url::Url::parse(std::str::from_utf8(bytes).unwrap()).unwrap();
-
-      app_state::handle_nonuser_event(EventWrapper::StaticEvent(Event::Opened { urls: vec![url] }));
+      handle_deep_link(webpage_url);
 
       YES
     }
@@ -631,6 +653,11 @@ pub fn create_delegate_class() {
       did_finish_launching as extern "C" fn(&mut Object, Sel, id, id) -> BOOL,
     );
 
+    decl.add_method(
+      sel!(application:openURL:options:),
+      application_open_url as extern "C" fn(&mut Object, Sel, id, id, id) -> BOOL,
+    );
+
     decl.add_method(
       sel!(application:continueUserActivity:restorationHandler:),
       application_continue as extern "C" fn(&mut Object, Sel, id, id, id) -> BOOL,