feat(windows): add sharedbuffer implement and example

[defims]

What kind of change does this PR introduce?

• Bugfix
• Feature
• Docs
• Code style update
• Refactor
• Build-related changes
• Other, please describe:

Does this PR introduce a breaking change?

• Yes
• No

Checklist

• This PR will resolve Add PostSharedBufferToScript for making streaming possible #1110 feat: synchronous communication between webview and rust #454
• A change file is added if any packages will require a version bump due to this PR per the instructions in the readme.
• I have added a convincing reason for adding this feature, if necessary
• It can be built on all targets and pass CI/CD.

Other information

Two methods, webview.create_shared_buffer() and webview.post_shared_buffer_to_script(), were added to the WebViewExtWindows trait, Since these are two Windows-specific methods.
Because manual memory management is risky, the new methods do not provide any additional helper functions to manage memory. Users are responsible for managing memory themselves.

[dklassic]

Hey @defims thanks for contributing! Though we have enforced commit signing so I'll need you to sign your commit before we can merge it.

[defims]

Hey @defims thanks for contributing! Though we have enforced commit signing so I'll need you to sign your commit before we can merge it.

@dklassic My pleasure. I have resubmitted it and signed the commit. Please check it again.😊

[amrbashir]

Same as #1109 this PR is only exposing APIs that can be accessed through webview.controller and I don't see any value in adding it here tbh.

[defims]

Same as #1109 this PR is only exposing APIs that can be accessed through webview.controller and I don't see any value in adding it here tbh.

@amrbashir Thank you for your review.
SharedBuffer is a zero-copy IPC method that has the following benefits:

• Reduces memory usage
• Lowers I/O overhead
• Improves communication performance
• Facilitates communication of large amounts of data (e.g., printing)

However, as you are concerned, it is a high-cost method with few applicable scenarios. It is currently only available on Windows.

For these reasons, I have not wrapped related methods too much. Instead, I only expose basic APIs on WebViewExtWindows. This allows us to cover a small number of applicable scenarios with the lowest maintenance cost. We do not need to consider the burden of use too much, as users can manage the burden themselves.

WKWebView and WebKitGTK currently do not have similar APIs. The cost of simulating them with existing interfaces is too high, so they have not been added yet. If the relevant API documentation is provided, I will be happy to add them and encapsulate them into a unified interface.

[amrbashir]

I meant that these newly exposed APIs can just be accessed by doing the following without adding it explicitly in wry:

let controller = webview.controller();
let webview2 = controller.CoreWebview2().unwrap().cast::<ICoreWebView2_19>().unwrap();
let environment = webview2.Environment().unwrap().cast::<ICoreWebView2Environment12>().unwrap();

// use webview2 & environment to create and post the shared buffer

Same goes for #1109

[defims]

I meant that these newly exposed APIs can just be accessed by doing the following without adding it explicitly in wry:

let controller = webview.controller();
let webview2 = controller.CoreWebview2().unwrap().cast::<ICoreWebView2_19>().unwrap();
let environment = webview2.Environment().unwrap().cast::<ICoreWebView2Environment12>().unwrap();

// use webview2 & environment to create and post the shared buffer

Same goes for #1109

Wow! That's great. I didn't notice this method before. This method can get the webview2 and environment, which means we can call the relevant webview2 methods. This pull request can be merged now. Thanks!

I tried it, and it worked. 🎉 Here is the test code:

use windows::ComInterface;
let controller = webview.controller();
let webview2 = unsafe { controller.CoreWebView2() }.unwrap().cast::<ICoreWebView2_19>().unwrap();
let environment = unsafe { webview2.Environment() }.unwrap().cast::<ICoreWebView2Environment12>().unwrap();
let _ = unsafe { webview2.AddHostObjectToScript(w!("i32"), &mut i32_variant.0) };
let shared_buffer = unsafe { webview.create_shared_buffer(1024) }.unwrap());
let _ = unsafe { environment.PostSharedBufferToScript(sharedbuffer, access, additionaldataasjson) };