mozilla-central/testing/web-platform/tests/IndexedDB/idbcursor_continue_delete_objectstore.any.js (file symbol)

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// META: title=IDBObjectStore.delete() and IDBCursor.continue()
// META: global=window,worker
// META: script=resources/support.js
'use strict';
async_test(t => {
/* The goal here is to test that any prefetching of cursor values performs
* correct invalidation of prefetched data. This test is motivated by the
* particularities of the Firefox implementation of preloading, and is
* specifically motivated by an edge case when prefetching prefetches at
* least 2 extra records and at most determines whether a mutation is
* potentially relevant based on current cursor position and direction and
* does not test for key equivalence. Future implementations may want to
* help refine this test if their cursors are more clever.
*
* Step-wise we:
* - Open a cursor, returning key 0.
* - When the cursor request completes, without yielding control:
* - Issue a delete() call that won't actually delete anything but looks
* relevant. This should purge prefetched records 1 and 2.
* - Issue a continue() which should result in record 1 being fetched
* again and record 2 being prefetched again.
* - Delete record 2. Unless there's a synchronously available source
* of truth, the data from continue() above will not be present and
* we'll expect the implementation to need to set a flag to invalidate
* the prefetched data when it arrives.
* - When the cursor request completes, validate we got record 1 and issue
* a continue.
* - When the request completes, we should have a null cursor result value
* because 2 was deleted.
*/
let db;
let count = 0;
const records =
[{pKey: 'primaryKey_0'}, {pKey: 'primaryKey_1'}, {pKey: 'primaryKey_2'}];
// This is a key that is not present in the database, but that is known to
// be relevant to a forward iteration of the above keys by comparing to be
// greater than all of them.
const plausibleFutureKey = 'primaryKey_9';
let open_rq = createdb(t);
open_rq.onupgradeneeded = function(e) {
db = e.target.result;
let objStore = db.createObjectStore('test', {keyPath: 'pKey'});
for (let i = 0; i < records.length; i++)
objStore.add(records[i]);
};
open_rq.onsuccess = t.step_func(CursorDeleteRecord);
function CursorDeleteRecord(e) {
let txn = db.transaction('test', 'readwrite', {durability: 'relaxed'});
let object_store = txn.objectStore('test');
let cursor_rq = object_store.openCursor();
let iteration = 0;
cursor_rq.onsuccess = t.step_func(function(e) {
let cursor = e.target.result;
switch (iteration) {
case 0:
object_store.delete(plausibleFutureKey);
assert_true(cursor != null, 'cursor valid');
assert_equals(cursor.value.pKey, records[iteration].pKey);
cursor.continue();
object_store.delete(records[2].pKey);
break;
case 1:
assert_true(cursor != null, 'cursor valid');
assert_equals(cursor.value.pKey, records[iteration].pKey);
cursor.continue();
break;
case 2:
assert_equals(cursor, null, 'cursor no longer valid');
break;
};
iteration++;
});
txn.oncomplete = t.step_func(VerifyRecordWasDeleted);
}
function VerifyRecordWasDeleted(e) {
let cursor_rq = db.transaction('test', 'readonly', {durability: 'relaxed'})
.objectStore('test')
.openCursor();
cursor_rq.onsuccess = t.step_func(function(e) {
let cursor = e.target.result;
if (!cursor) {
assert_equals(count, 2, 'count');
t.done();
}
assert_equals(cursor.value.pKey, records[count].pKey);
count++;
cursor.continue();
});
}
}, 'Object store - remove a record from the object store while iterating cursor');