Skip to content

feat(jco): add future lower tests #1422

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
vados-cosmonic merged 12 commits into from
Apr 28, 2026
Merged

feat(jco): add future lower tests #1422

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
12 commits
Select commit Hold shift + click to select a range
e014800
feat(jco): add future lower tests, refactor existing
vados-cosmonic Apr 20, 2026
bbfb5ed
feat(bindgen): fill out future lower impl
vados-cosmonic Apr 27, 2026
68ab1f5
test(jco): fill in nested future stream lower test
vados-cosmonic Apr 27, 2026
3687922
fix(bindgen): fix task.return param spill check
vados-cosmonic Apr 27, 2026
661fd5c
test(jco): update tests for future lift/lower, add list<u32, 3>
vados-cosmonic Apr 27, 2026
077fd19
test(jco): add links to float reinterpret issue
vados-cosmonic Apr 27, 2026
a40d0f8
test(jco): fix stream-tx.wasm reference
vados-cosmonic Apr 28, 2026
a578aac
feat(bindgen): implement future<future<t>> lower
vados-cosmonic Apr 28, 2026
975bd6c
fix(bindgen): progress towards nested futture read
vados-cosmonic Apr 28, 2026
3e5d330
chore(bindgen): update comment
vados-cosmonic Apr 28, 2026
b5e203a
test(jco): fix check for function asyncness
vados-cosmonic Apr 28, 2026
f73e64f
fix(bindgen): lint & nested future check
vados-cosmonic Apr 28, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
261 changes: 246 additions & 15 deletions crates/js-component-bindgen/src/function_bindgen.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -4,8 +4,9 @@ use std::mem;

use heck::{ToLowerCamelCase, ToUpperCamelCase};
use wasmtime_environ::component::{
CanonicalOptions, InterfaceType, ResourceIndex, TypeComponentLocalErrorContextTableIndex,
TypeFutureTableIndex, TypeResourceTableIndex, TypeStreamTableIndex,
CanonicalOptions, CanonicalOptionsDataModel, InterfaceType, LinearMemoryOptions, ResourceIndex,
TypeComponentLocalErrorContextTableIndex, TypeFutureTableIndex, TypeResourceTableIndex,
TypeStreamTableIndex,
};
use wit_bindgen_core::abi::{Bindgen, Bitcast, Instruction};
use wit_component::StringEncoding;
Expand Down Expand Up @@ -87,6 +88,7 @@ pub enum ResourceExtraData {
Future {
table_idx: TypeFutureTableIndex,
elem_ty: Option<PayloadTypeMetadata>,
nesting_level: u32,
},
ErrorContext {
table_idx: TypeComponentLocalErrorContextTableIndex,
Expand Down Expand Up @@ -2685,19 +2687,230 @@ impl Bindgen for FunctionBindgen<'_> {
results.push(item.clone());
}

Instruction::FutureLower { .. } => {
// TODO: convert this return of the lifted Future:
//
// ```
// return BigInt(writeEndWaitableIdx) << 32n | BigInt(readEndWaitableIdx);
// ```
//
// Into a component-local Future instance
//
Instruction::FutureLower { ty, .. } => {
let debug_log_fn = self.intrinsic(Intrinsic::DebugLog);
let get_or_create_async_state_fn = self.intrinsic(Intrinsic::Component(
ComponentIntrinsic::GetOrCreateAsyncState,
));
let gen_future_host_inject_fn = self.intrinsic(Intrinsic::AsyncFuture(
AsyncFutureIntrinsic::GenFutureHostInjectFn,
));
let is_future_lowerable_object_fn = self.intrinsic(Intrinsic::AsyncFuture(
AsyncFutureIntrinsic::IsFutureLowerableObject,
));
let nested_future_symbol = self.intrinsic(Intrinsic::AsyncFuture(
AsyncFutureIntrinsic::NestedFutureSymbol,
));

let component_idx = self.canon_opts.instance.as_u32();

let future_arg = operands
.first()
.expect("unexpectedly missing ErrorContextLower arg");
results.push(future_arg.clone());

// Build the lowering function for the type produced by the future
let type_id = &crate::dealias(self.resolve, *ty);
let ResourceTable {
imported: true,
data:
ResourceData::Guest {
extra:
Some(ResourceExtraData::Future {
table_idx: future_table_idx_ty,
nesting_level,
elem_ty,
}),
..
},
} = self
.resource_map
.get(type_id)
.expect("missing resource mapping for future lower")
else {
unreachable!("invalid resource table observed during future lower");
};
let future_table_idx = future_table_idx_ty.as_u32();

// Generate payload metadata ('elemMeta')
let (
payload_type_name_js,
lift_fn_js,
lower_fn_js,
payload_is_none,
payload_is_numeric,
payload_is_borrow,
payload_is_async_value,
payload_size32_js,
payload_align32_js,
payload_flat_count_js,
) = match elem_ty {
Some(PayloadTypeMetadata {
ty: _,
iface_ty,
lift_js_expr,
lower_js_expr,
size32,
align32,
flat_count,
}) => (
format!("'{iface_ty:?}'"),
lift_js_expr.as_str(),
lower_js_expr.as_str(),
"false",
format!(
"{}",
matches!(
iface_ty,
InterfaceType::U8
| InterfaceType::U16
| InterfaceType::U32
| InterfaceType::U64
| InterfaceType::S8
| InterfaceType::S16
| InterfaceType::S32
| InterfaceType::S64
| InterfaceType::Float32
| InterfaceType::Float64
)
),
format!("{}", matches!(iface_ty, InterfaceType::Borrow(_))),
format!(
"{}",
matches!(
iface_ty,
InterfaceType::Stream(_) | InterfaceType::Future(_)
)
),
size32.to_string(),
align32.to_string(),
flat_count.unwrap_or(0).to_string(),
),
None => (
"null".into(),
"() => {{ throw new Error('no lift fn'); }}",
"() => {{ throw new Error('no lower fn'); }}",
"true",
"false".into(),
"false".into(),
"false".into(),
"null".into(),
"null".into(),
"0".into(),
),
};

// Retrieve the realloc fn if present, in case lowering fns need to allocate
//
// The realloc fn is saved on the element metadata which is passed through to
// stream end and underlying buffer
let get_realloc_fn_js = match self.canon_opts.data_model {
CanonicalOptionsDataModel::LinearMemory(LinearMemoryOptions {
realloc: Some(realloc_idx),
..
}) => format!("() => realloc{}", realloc_idx.as_u32()),
_ => "undefined".into(),
};

let tmp = self.tmp();
let lowered_future_waitable_idx = format!("futureWaitableIdx{tmp}");

uwriteln!(
self.src,
r#"
if (!{is_future_lowerable_object_fn}({future_arg})) {{
{debug_log_fn}('[Instruction::FutureLower] object is not a Promise/Thenable', {{ {future_arg} }});
throw new Error('unrecognized future object (not Promise/Thenable)');
}}

const cstate{tmp} = {get_or_create_async_state_fn}({component_idx});
if (!cstate{tmp}) {{
throw new Error(`missing component state for component [{component_idx}]`);
}}

// TODO(feat): facilitate non utf8 string encoding for lowered futures
const stringEncoding = 'utf8';

let outermostReadEnd{tmp};
let futuresList{tmp} = [];
let future{tmp} = {future_arg};
let nextFuture{tmp};
let openedCount = -1;
let futureNestingLevel{tmp} = {nesting_level};

while (futureNestingLevel{tmp} >= 0) {{
const {{
writeEnd,
writeEndWaitableIdx,
readEnd,
readEndWaitableIdx
}} = cstate{tmp}.createFuture({{
tableIdx: {future_table_idx},
elemMeta: {{
liftFn: {lift_fn_js},
lowerFn: {lower_fn_js},
payloadTypeName: {payload_type_name_js},
isNone: {payload_is_none},
isNumeric: {payload_is_numeric},
isBorrowed: {payload_is_borrow},
isAsyncValue: {payload_is_async_value},
flatCount: {payload_flat_count_js},
align32: {payload_align32_js},
size32: {payload_size32_js},
stringEncoding,
getReallocFn: {get_realloc_fn_js},
}}
}});

const hostInjectFn = {gen_future_host_inject_fn}({{
promise: future{tmp},
stringEncoding,
hostWriteEnd: writeEnd,
}});
readEnd.setHostInjectFn(hostInjectFn);

const meta{tmp} = {{
isInnermost: futureNestingLevel{tmp} === {nesting_level},
level: futureNestingLevel{tmp},
}};

const innerFuture = future{tmp};
future{tmp} = {{ }};
future{tmp}[{nested_future_symbol}] = meta{tmp};
future{tmp}.readEndWaitableIdx = readEndWaitableIdx;
future{tmp}.writeEndWaitableIdx = writeEndWaitableIdx;
future{tmp}.futureTableIdx = {future_table_idx};
future{tmp}.componentIdx = {component_idx};
future{tmp}.then = async (resolve, reject) => {{
let p;
if (openedCount === {nesting_level}) {{
p = innerFuture;
}} else {{
openedCount++;
p = futuresList{tmp}[futuresList{tmp}.length - (openedCount + 1)];
}}

try {{
resolve(await p);
}} catch (err) {{
reject(err);
}}
}};

outermostReadEnd{tmp} = readEnd;

futuresList{tmp}.push(future{tmp});
futureNestingLevel{tmp}--;
}}

const readEnd{tmp} = outermostReadEnd{tmp};

// TODO: need to *lower* the internal future???

const {lowered_future_waitable_idx} = readEnd{tmp}.waitableIdx();
"#
);

results.push(lowered_future_waitable_idx);
}

Instruction::FutureLift { payload, ty } => {
Expand All @@ -2715,6 +2928,7 @@ impl Bindgen for FunctionBindgen<'_> {
Some(ResourceExtraData::Future {
table_idx: future_table_idx_ty,
elem_ty: future_element_ty,
..
}),
..
},
Expand Down Expand Up @@ -2801,10 +3015,13 @@ impl Bindgen for FunctionBindgen<'_> {
let get_or_create_async_state_fn = self.intrinsic(Intrinsic::Component(
ComponentIntrinsic::GetOrCreateAsyncState,
));
let gen_host_inject_fn = self.intrinsic(Intrinsic::AsyncStream(
AsyncStreamIntrinsic::GenHostInjectFn,
let gen_stream_host_inject_fn = self.intrinsic(Intrinsic::AsyncStream(
AsyncStreamIntrinsic::GenStreamHostInjectFn,
));

// TODO(???): A component could end up receiving a stream that it outputted,
// and the below would fail (imported: false)?

// Build the lowering function for the type produced by the stream
let type_id = &crate::dealias(self.resolve, *ty);
let ResourceTable {
Expand Down Expand Up @@ -2896,6 +3113,18 @@ impl Bindgen for FunctionBindgen<'_> {
),
};

// Retrieve the realloc fn if present, in case lowering fns need to allocate
//
// The realloc fn is saved on the element metadata which is passed through to
// stream end and underlying buffer
let get_realloc_fn_js = match self.canon_opts.data_model {
CanonicalOptionsDataModel::LinearMemory(LinearMemoryOptions {
realloc: Some(realloc_idx),
..
}) => format!("() => realloc{}", realloc_idx.as_u32()),
_ => "undefined".into(),
};

let tmp = self.tmp();
let lowered_stream_waitable_idx = format!("streamWaitableIdx{tmp}");
uwriteln!(
Expand Down Expand Up @@ -2926,6 +3155,7 @@ impl Bindgen for FunctionBindgen<'_> {
size32: {payload_size32_js},
// TODO(feat): facilitate non utf8 string encoding for lowered streams
stringEncoding: 'utf8',
geReallocFn: {get_realloc_fn_js},
}},
}});

Expand All @@ -2943,7 +3173,7 @@ impl Bindgen for FunctionBindgen<'_> {
readFn{tmp} = () => lockedReader.read();
}}

const hostInjectFn = {gen_host_inject_fn}({{
const hostInjectFn = {gen_stream_host_inject_fn}({{
readFn: readFn{tmp},
hostWriteEnd: hostWriteEnd{tmp},
}});
Expand All @@ -2952,6 +3182,7 @@ impl Bindgen for FunctionBindgen<'_> {
const {lowered_stream_waitable_idx} = readEnd{tmp}.waitableIdx();
"#
);

results.push(lowered_stream_waitable_idx);
}

Expand Down
Loading
Loading