Convert Vec<u8> in Rust to Uint8Array in Javascript

[yang282441848]

Api in Tauri covert Vec<u8> to number[] in javascript , and cover number[] to Uint8Array. There are two traverses in this step.This is's efficient way to transfer a large size of binary data from Rust to Javascript.

// tooling/api/src/fs.ts
async function readBinaryFile(
  filePath: string,
  options: FsOptions = {}
): Promise<Uint8Array> {
  const arr = await invokeTauriCommand<number[]>({
    __tauriModule: 'Fs',
    message: {
      cmd: 'readFile',
      path: filePath,
      options
    }
  })

  return Uint8Array.from(arr)
}

Is there any way to cover Vec<u8> to Uint8Array without memory copy?

[yang282441848]

I want to make a plugin to decode rtsp and render it to webview.

1. use ffmpeg to get yuv data from rtsp. [Rust]
2. use tauri event to pass yuv data to webview. [Rust] -> [webview]
3. use webgl to render videos.[webview]

There are chunk datas from Rust to webview.

[FabianLars]

Is there any way to cover Vec to Uint8Array without memory copy?

Nope. and it gets worse than that, the binary data will be converted to a json string first because that's what the current IPC requires. (btw shouldn't converting number[] to Uint8Array be relatively cheap?).

You may have more luck with custom protocols - examples:
https://github.com/tauri-apps/tauri/tree/dev/examples/streaming
https://github.com/JonasKruckenberg/pisano/
It should handle binary payloads much better than the IPC

[yang282441848]

Thx so much.

Why not use shared memory for IPC? It turns to be 2fps from 25fps after using IPC by emit api....

I will try to use streaming

[vdvman1]

Not all the webviews that Tauri use support shared memory

[FabianLars]

Why not use shared memory for IPC?

Because this is not possible yet. There is no WebView API we could use for that yet, but soon ™️ as all webviews apparently have something experimental/in-preview