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// |reftest| skip-if(!this.hasOwnProperty('FinalizationRegistry')) async -- FinalizationRegistry is not enabled unconditionally
// Copyright (C) 2019 Leo Balter. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
esid: sec-finalization-registry-target
description: >
cleanupCallback has only one optional chance to be called for a GC that cleans
up a registered Object target.
info: |
FinalizationRegistry.prototype.cleanupSome ( [ _callback_ ] )
3. If _callback_ is present and IsCallable(_callback_) is *false*, throw a
*TypeError* exception.
4. Perform ? CleanupFinalizationRegistry(_finalizationRegistry_, _callback_).
5. Return *undefined*.
Execution
At any time, if a set of objects and/or symbols _S_ is not live, an ECMAScript
implementation may perform the following steps atomically:
1. For each element _value_ of _S_, do
...
b. For each FinalizationRegistry _fg_ such that _fg_.[[Cells]] contains a
Record _cell_ such that _cell_.[[WeakRefTarget]] is _value_,
i. Set _cell_.[[WeakRefTarget]] to ~empty~.
ii. Optionally, perform HostEnqueueFinalizationRegistryCleanupJob(_fg_).
features: [FinalizationRegistry.prototype.cleanupSome, FinalizationRegistry, async-functions, host-gc-required]
flags: [async, non-deterministic]
includes: [async-gc.js, compareArray.js]
---*/
let cleanupCallback = 0;
let holdings = [];
function cb(holding) {
holdings.push(holding);
}
let finalizationRegistry = new FinalizationRegistry(function() {
cleanupCallback += 1;
});
function emptyCells() {
let target = {};
finalizationRegistry.register(target, 'a');
let prom = asyncGC(target);
target = null;
return prom;
}
emptyCells().then(async function() {
await Promise.resolve(1);
finalizationRegistry.cleanupSome(cb);
// cleanupSome will be invoked if there are empty cells left. If the
// cleanupCallback already ran, then cb won't be called.
let expectedCalled = cleanupCallback === 1 ? 0 : 1;
// This asserts the registered object was emptied in the previous GC.
assert.sameValue(holdings.length, expectedCalled, 'cleanupSome callback for the first time');
// At this point, we can't assert if cleanupCallback was called, because it's
// optional. Although, we can finally assert it's not gonna be called anymore
// for the other executions of the Garbage Collector.
// The chance of having it called only happens right after the
// cell.[[WeakRefTarget]] is set to empty.
assert(cleanupCallback >= 0, 'cleanupCallback might be 0');
assert(cleanupCallback <= 1, 'cleanupCallback might be 1');
// Restoring the cleanupCallback variable to 0 will help us asserting the
// finalizationRegistry callback is not called again.
cleanupCallback = 0;
await $262.gc();
await Promise.resolve(2); // tick
finalizationRegistry.cleanupSome(cb);
assert.sameValue(holdings.length, expectedCalled, 'cleanupSome callback is not called anymore, no empty cells');
assert.sameValue(cleanupCallback, 0, 'cleanupCallback is not called again #1');
await $262.gc();
await Promise.resolve(3); // tick
finalizationRegistry.cleanupSome(cb);
assert.sameValue(holdings.length, expectedCalled, 'cleanupSome callback is not called again #2');
assert.sameValue(cleanupCallback, 0, 'cleanupCallback is not called again #2');
if (holdings.length) {
assert.compareArray(holdings, ['a']);
}
await $262.gc();
}).then($DONE, resolveAsyncGC);
|
