CountBleck 2956281845 Support WebAssembly.{instantiate,compile}Streaming() (#20503) ...

### What does this PR do?

<!-- **Please explain what your changes do** -->

This PR should fix #14219 and implement
`WebAssembly.instantiateStreaming()` and
`WebAssembly.compileStreaming()`.

This is a mixture of WebKit's implementation (using a helper,
`handleResponseOnStreamingAction`, also containing a fast-path for
blobs) and some of Node.js's validation (error messages) and its
builtin-based strategy to consume chunks from streams.

`src/bun.js/bindings/GlobalObject.zig` has a helper function
(`getBodyStreamOrBytesForWasmStreaming`), called by C++, to validate the
response (like
[Node.js](214e4db60e/lib/internal/wasm_web_api.js)
does) and to extract the data from the response, either as a slice/span
(if we can get the data synchronously), or as a `ReadableStream` body
(if the data is still pending or if it is a file/S3 `Blob`).

In C++, `handleResponseOnStreamingAction` is called by
`compileStreaming` and `instantiateStreaming` on the
`JSC::GlobalObjectMethodTable`, just like in
[WebKit](97ee3c598a/Source/WebCore/bindings/js/JSDOMGlobalObject.cpp (L517)).
It calls the aforementioned Zig helper for validation and getting the
response data. The data is then fed into `JSC::Wasm::StreamingCompiler`.

If the data is received as a `ReadableStream`, then we call a JS builtin
in `WasmStreaming.ts` to iterate over each chunk of the stream, like
[Node.js](214e4db60e/lib/internal/wasm_web_api.js (L50-L52))
does. The `JSC::Wasm::StreamingCompiler` is passed into JS through a new
wrapper object, `WebCore::WasmStreamingCompiler`, like
[Node.js](214e4db60e/src/node_wasm_web_api.h)
does. It has `addBytes`, `finalize`, `error`, and (unused) `cancel`
methods to mirror the underlying JSC class.

(If there's a simpler way to do this, please let me know...that would be
very much appreciated)

- [x] Code changes

### How did you verify your code works?

<!-- **For code changes, please include automated tests**. Feel free to
uncomment the line below -->

I wrote automated tests (`test/js/web/fetch/wasm-streaming.test`).

<!-- If JavaScript/TypeScript modules or builtins changed: -->

- [x] I included a test for the new code, or existing tests cover it
- [x] I ran my tests locally and they pass (`bun-debug test
test/js/web/fetch/wasm-streaming.test`)

<!-- If Zig files changed: -->

- [x] I checked the lifetime of memory allocated to verify it's (1)
freed and (2) only freed when it should be (NOTE: consumed `AnyBlob`
bodies are freed, and all other allocations are in C++ and either GCed
or ref-counted)
- [x] I included a test for the new code, or an existing test covers it
(NOTE: via JS/TS unit test)
- [x] JSValue used outside of the stack is either wrapped in a
JSC.Strong or is JSValueProtect'ed (NOTE: N/A, JSValue never used
outside the stack)
- [x] I wrote TypeScript/JavaScript tests and they pass locally
(`bun-debug test test/js/web/fetch/wasm-streaming.test`)

---------

Co-authored-by: graphite-app[bot] <96075541+graphite-app[bot]@users.noreply.github.com>

2025-07-28 11:59:45 -07:00

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