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// Copyright 2021 The Dawn Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef DAWNWIRE_CLIENT_REQUESTTRACKER_H_
#define DAWNWIRE_CLIENT_REQUESTTRACKER_H_
#include "common/Assert.h"
#include "common/NonCopyable.h"
#include <cstdint>
#include <map>
namespace dawn_wire { namespace client {
class Device;
class MemoryTransferService;
template <typename Request>
class RequestTracker : NonCopyable {
public:
~RequestTracker() {
ASSERT(mRequests.empty());
}
uint64_t Add(Request&& request) {
mSerial++;
mRequests.emplace(mSerial, request);
return mSerial;
}
bool Acquire(uint64_t serial, Request* request) {
auto it = mRequests.find(serial);
if (it == mRequests.end()) {
return false;
}
*request = std::move(it->second);
mRequests.erase(it);
return true;
}
template <typename CloseFunc>
void CloseAll(CloseFunc&& closeFunc) {
// Call closeFunc on all requests while handling reentrancy where the callback of some
// requests may add some additional requests. We guarantee all callbacks for requests
// are called exactly onces, so keep closing new requests if the first batch added more.
// It is fine to loop infinitely here if that's what the application makes use do.
while (!mRequests.empty()) {
// Move mRequests to a local variable so that further reentrant modifications of
// mRequests don't invalidate the iterators.
auto allRequests = std::move(mRequests);
for (auto& it : allRequests) {
closeFunc(&it.second);
}
}
}
template <typename F>
void ForAll(F&& f) {
for (auto& it : mRequests) {
f(&it.second);
}
}
private:
uint64_t mSerial;
std::map<uint64_t, Request> mRequests;
};
}} // namespace dawn_wire::client
#endif // DAWNWIRE_CLIENT_REQUESTTRACKER_H_