gecko-dev/dom/ipc/SharedMapChangeEvent.h
Kris Maglione 8316d5a0c0 Bug 1463587: Part 3 - Add bindings for SharedMap, and expose it via process message managers. r=erahm,baku,bz
This is the first basic implementation of a shared-memory key-value store for
JS message managers. It has one read-write endpoint in the parent process, and
separate read-only endpoints for each child-process message manager.

Changes to the parent endpoint are broadcast to the children as snapshots.
Each snapshot triggers a "change" event with a list of changed keys.

It currently has the following limitations:

- It only supports basic structured clone data. There's no support for blobs,
  input streams, message ports... Blob support will be added in a follow-up
  patch.

- Changes are currently only broadcast to child endpoints when flush() is
  explicitly called in the parent, or when new child processes are launched.
  In a follow-up, this will be changed to automatically flush after changes
  when the event loop is idle.

- All set operations clone their inputs synchronously, which means that
  there's no trivial way for callers to batch multiple changes to a single key
  without some additional effort. It might be useful to add a
  delayed-serialization option to the .set() call in a follow-up, for callers
  who are sure they know what they're doing.

MozReview-Commit-ID: IM8a3UgejXU

--HG--
extra : rebase_source : 66c92d538a5485349bc789028fdc3a6806bc5d5a
extra : source : 2ebaf5f8c6055b11b11d7ec334d54ee941115d48
2018-06-29 14:55:27 -07:00

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1.4 KiB
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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* vim: set ts=8 sts=4 et sw=4 tw=99: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef dom_ipc_SharedMapChangeEvent_h
#define dom_ipc_SharedMapChangeEvent_h
#include "mozilla/dom/MozSharedMapBinding.h"
#include "mozilla/dom/Event.h"
#include "nsTArray.h"
namespace mozilla {
namespace dom {
namespace ipc {
class SharedMapChangeEvent final : public Event
{
public:
NS_INLINE_DECL_REFCOUNTING_INHERITED(SharedMapChangeEvent, Event)
JSObject* WrapObjectInternal(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override
{
return MozSharedMapChangeEvent_Binding::Wrap(aCx, this, aGivenProto);
}
static already_AddRefed<SharedMapChangeEvent>
Constructor(EventTarget* aEventTarget,
const nsAString& aType,
const MozSharedMapChangeEventInit& aInit);
void GetChangedKeys(nsTArray<nsString>& aChangedKeys) const
{
aChangedKeys.AppendElements(mChangedKeys);
}
protected:
~SharedMapChangeEvent() override = default;
private:
explicit SharedMapChangeEvent(EventTarget* aEventTarget)
: Event(aEventTarget, nullptr, nullptr)
{}
nsTArray<nsString> mChangedKeys;
};
} // ipc
} // dom
} // mozilla
#endif // dom_ipc_SharedMapChangeEvent_h