115 lines
3.3 KiB
C++
115 lines
3.3 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* 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
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef mozilla_dom_RequestCallbackManager_h
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#define mozilla_dom_RequestCallbackManager_h
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#include <limits>
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#include "mozilla/HashTable.h"
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#include "mozilla/RefPtr.h"
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#include "nsTArray.h"
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#include "nsThreadUtils.h"
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namespace mozilla::dom {
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template <typename RequestCallback>
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struct RequestCallbackEntry {
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RequestCallbackEntry(RequestCallback& aCallback, uint32_t aHandle)
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: mCallback(&aCallback), mHandle(aHandle) {
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LogTaskBase<RequestCallback>::LogDispatch(mCallback);
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}
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~RequestCallbackEntry() = default;
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// Comparator operators to allow RemoveElementSorted with an
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// integer argument on arrays of RequestCallback
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bool operator==(uint32_t aHandle) const { return mHandle == aHandle; }
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bool operator<(uint32_t aHandle) const { return mHandle < aHandle; }
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RefPtr<RequestCallback> mCallback;
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uint32_t mHandle;
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};
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template <typename RequestCallback>
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class RequestCallbackManager {
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public:
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RequestCallbackManager() = default;
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~RequestCallbackManager() = default;
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nsresult Schedule(RequestCallback& aCallback, uint32_t* aHandle) {
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if (mCallbackCounter == std::numeric_limits<uint32_t>::max()) {
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// Can't increment without overflowing; bail out
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return NS_ERROR_NOT_AVAILABLE;
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}
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uint32_t newHandle = ++mCallbackCounter;
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mCallbacks.AppendElement(RequestCallbackEntry(aCallback, newHandle));
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*aHandle = newHandle;
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return NS_OK;
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}
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bool Cancel(uint32_t aHandle) {
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// mCallbacks is stored sorted by handle
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if (mCallbacks.RemoveElementSorted(aHandle)) {
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return true;
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}
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Unused << mCanceledCallbacks.put(aHandle);
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return false;
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}
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bool IsEmpty() const { return mCallbacks.IsEmpty(); }
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bool IsCanceled(uint32_t aHandle) const {
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return !mCanceledCallbacks.empty() && mCanceledCallbacks.has(aHandle);
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}
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void Take(nsTArray<RequestCallbackEntry<RequestCallback>>& aCallbacks) {
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aCallbacks = std::move(mCallbacks);
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mCanceledCallbacks.clear();
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}
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void Unlink() { mCallbacks.Clear(); }
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void Traverse(nsCycleCollectionTraversalCallback& aCB) {
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for (auto& i : mCallbacks) {
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NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(
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aCB, "RequestCallbackManager::mCallbacks[i]");
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aCB.NoteXPCOMChild(i.mCallback);
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}
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}
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private:
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nsTArray<RequestCallbackEntry<RequestCallback>> mCallbacks;
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// The set of frame request callbacks that were canceled but which we failed
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// to find in mRequestCallbacks.
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HashSet<uint32_t> mCanceledCallbacks;
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/**
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* The current frame request callback handle
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*/
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uint32_t mCallbackCounter = 0;
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};
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template <class RequestCallback>
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inline void ImplCycleCollectionUnlink(
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RequestCallbackManager<RequestCallback>& aField) {
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aField.Unlink();
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}
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template <class RequestCallback>
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inline void ImplCycleCollectionTraverse(
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nsCycleCollectionTraversalCallback& aCallback,
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RequestCallbackManager<RequestCallback>& aField, const char* aName,
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uint32_t aFlags) {
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aField.Traverse(aCallback);
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}
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} // namespace mozilla::dom
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#endif
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