foundationdb/fdbclient/Notified.h

82 lines
2.3 KiB
C++

/*
* Notified.h
*
* This source file is part of the FoundationDB open source project
*
* Copyright 2013-2018 Apple Inc. and the FoundationDB project 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 FDBCLIENT_NOTIFIED_H
#define FDBCLIENT_NOTIFIED_H
#pragma once
#include "FDBTypes.h"
#include "flow/TDMetric.actor.h"
struct NotifiedVersion {
NotifiedVersion( StringRef& name, StringRef const &id, Version version = 0 ) : val(name, id, version) { val = version; }
NotifiedVersion( Version version = 0 ) : val(StringRef(), StringRef(), version) {}
void initMetric(const StringRef& name, const StringRef &id) {
Version version = val;
val.init(name, id);
val = version;
}
Future<Void> whenAtLeast( Version limit ) {
if (val >= limit)
return Void();
Promise<Void> p;
waiting.push( std::make_pair(limit,p) );
return p.getFuture();
}
Version get() const { return val; }
void set( Version v ) {
ASSERT( v >= val );
if (v != val) {
val = v;
std::vector<Promise<Void>> toSend;
while ( waiting.size() && v >= waiting.top().first ) {
Promise<Void> p = std::move(waiting.top().second);
waiting.pop();
toSend.push_back(p);
}
for(auto& p : toSend) {
p.send(Void());
}
}
}
void operator=( Version v ) {
set( v );
}
NotifiedVersion(NotifiedVersion&& r) noexcept(true) : waiting(std::move(r.waiting)), val(std::move(r.val)) {}
void operator=(NotifiedVersion&& r) noexcept(true) { waiting = std::move(r.waiting); val = std::move(r.val); }
private:
typedef std::pair<Version,Promise<Void>> Item;
struct ItemCompare {
bool operator()(const Item& a, const Item& b) { return a.first > b.first; }
};
std::priority_queue<Item, std::vector<Item>, ItemCompare> waiting;
VersionMetricHandle val;
};
#endif