fix crash when setting datastore and add methods to fetch all datastores and to remove a datastore

[Simon-Laux]

• fix: crash when using WebViewBuilderExtDarwin.with_data_store_identifier
  • [bug] WebviewWindowBuilder.data_store_identifier crashes tauri#12843 (comment)
• feat: macOS: add wry::fetch_all_data_store_identifiers and wry::remove_data_store

Progress

• rebase
• corresponding tauri pr (add AppHandle.fetch_data_store_identifiers and AppHandle.remove_data_store tauri#12900)
• signed commits
• changes file
• find a way to error instead of segfaulting when removing a datastore that is still in use

[github-actions]

Package Changes Through 64d4869

There are 1 changes which include wry with patch

Planned Package Versions

The following package releases are the planned based on the context of changes in this pull request.

package	current	next
wry	0.50.3	0.50.4

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[lucasfernog]

I just moved your method to the WebView struct (via ext trait) and made it synchronously (so it's easier to use in tauri)
great work as usual!

[lucasfernog]

oh I noticed remove_data_store is giving me a segfault.
the error is probably because of this:

Release any [WKWebView](https://developer.apple.com/documentation/webkit/wkwebview) instances using the data store before you call this method. If the system cannot complete removal of the data store, this throws an error.

but it shouldn't segfault, I tried to map the error manually but it cannot go past err.code()

EDIT: even if i close the webview first, I get the error. So the data store is probably still around

// Copyright 2020-2023 Tauri Programme within The Commons Conservancy
// SPDX-License-Identifier: Apache-2.0
// SPDX-License-Identifier: MIT

use objc2_foundation::NSUUID;
use tao::{
  event::{Event, WindowEvent},
  event_loop::{ControlFlow, EventLoop},
  window::WindowBuilder,
};
use wry::{WebView, WebViewBuilder, WebViewBuilderExtDarwin, WebViewExtDarwin};

fn main() -> wry::Result<()> {
  let event_loop = EventLoop::new();
  let window = WindowBuilder::new().build(&event_loop).unwrap();

  let bytes = NSUUID::new().as_bytes();
  let builder = WebViewBuilder::new()
    .with_url("http://tauri.app")
    .with_data_store_identifier(bytes);

  let _webview = builder.build(&window)?;

  let mut w = Some(_webview);
  let mut ww = Some(window);

  let p = event_loop.create_proxy();

  event_loop.run(move |event, _, control_flow| {
    *control_flow = ControlFlow::Wait;

    if let Event::UserEvent(_) = event {
      WebView::remove_data_store(&bytes).unwrap();
      println!("{:?}", WebView::fetch_data_store_identifiers());
    }

    if let Event::WindowEvent {
      event: WindowEvent::CloseRequested,
      ..
    } = event
    {
      w.take();
      ww.take();

      let p = p.clone();
      std::thread::spawn(move || {
        std::thread::sleep_ms(3000);
        p.send_event(());
      });
      //*control_flow = ControlFlow::Exit;
    }
  });
}

[lucasfernog]

gotta fix the remove function :(

[Simon-Laux]

I believe all IO functions that potentially need to wait for disk should be async and I already solved the tauri part, so I'm not sure why we should change it to be blocking.
Especially because this runs in the main thread, it should not be blocking IMO. Blocking main thread means that the UI of the app freezes, which is super bad UX, so we should avoid it where possible.

[Simon-Laux]

EDIT: even if i close the webview first, I get the error. So the data store is probably still around

correct there is segfault if the web view is still active, thanks for finding that. But it works for me when the web view is closed, I just tried it in my example https://github.com/Simon-Laux/tauri-experiments/tree/mac_data_store_experiments3/examples/data_store_tauri.

await window.api.new_window()
// then delete it, this works if you closed the new window, but if it is still open this segfaults
let i = await window.api.get_ids()
await window.api.delete_id(i[0])

[lucasfernog]

I'll merge this because it seems unrelated to this PR, but something about the webview drop is not releasing the data store properly.

[Simon-Laux]

but something about the webview drop is not releasing the data store properly.

are you sure? because my example worked where I removed the data store of different web views, maybe you call it too early in your testing code?

nevertheless the error should return an error and not crash.