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Storage events are fired either directly after getting response from synchronous SetItem call or through observers. When a new onstorage event listener is added, we sycnhronously register an observer in the parent process. There's always only one observer actor per content process. PBackgroundLSDatabase is now managed by a new PBackgroundLSObject protocol. PBackgroundLSObject is needed to eliminate the need to pass the principal info and document URI everytime a write operation occurs. Preparation of an observer shares some states with preparation of a datastore, so common stuff now lives in LSRequestBase and preparation of a datastore now implements a nested state machine. This patch was enhanced by asuth to drop observers only when the last storage listener is removed. EventListenerRemoved is invoked on any removal, not just the final removal, so we need to make sure it's the final removal before dropping observer.
56 lines
1.6 KiB
Plaintext
56 lines
1.6 KiB
Plaintext
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this file,
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* You can obtain one at http://mozilla.org/MPL/2.0/. */
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include protocol PBackground;
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namespace mozilla {
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namespace dom {
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struct LSRequestPrepareDatastoreResponse
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{
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uint64_t datastoreId;
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};
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struct LSRequestPrepareObserverResponse
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{
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uint64_t observerId;
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};
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union LSRequestResponse
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{
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nsresult;
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LSRequestPrepareDatastoreResponse;
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LSRequestPrepareObserverResponse;
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};
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protocol PBackgroundLSRequest
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{
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manager PBackground;
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parent:
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// The Cancel message is used to avoid a possible dead lock caused by a CPOW
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// sending a synchronous message from the main thread in the chrome process
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// to the main thread in the content process at the time we are blocking
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// the main thread in the content process to handle a request.
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// We use the PBackground thread on the parent side to handle requests, but
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// sometimes we need to get information from principals and that's currently
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// only possible on the main thread. So if the main thread in the chrome
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// process is blocked by a CPOW operation, our request must wait for the CPOW
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// operation to complete. However the CPOW operation can't complete either
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// because we are blocking the main thread in the content process.
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// The dead lock is prevented by canceling our nested event loop in the
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// content process when we receive a synchronous IPC message from the parent.
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async Cancel();
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async Finish();
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child:
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async __delete__(LSRequestResponse response);
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async Ready();
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};
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} // namespace dom
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} // namespace mozilla
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