danicoin/src/System/Latch.cpp
2015-05-27 13:28:09 +01:00

120 lines
2.8 KiB
C++
Executable file

// Copyright (c) 2012-2015, The CryptoNote developers, The Bytecoin developers
//
// This file is part of Bytecoin.
//
// Bytecoin is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Bytecoin is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with Bytecoin. If not, see <http://www.gnu.org/licenses/>.
#include "Latch.h"
#include <cassert>
#include <System/Dispatcher.h>
namespace System {
namespace {
struct LatchWaiter {
LatchWaiter* next;
void* context;
};
}
Latch::Latch() : dispatcher(nullptr) {
}
Latch::Latch(Dispatcher& dispatcher) : dispatcher(&dispatcher), value(0) {
}
Latch::Latch(Latch&& other) : dispatcher(other.dispatcher) {
if (dispatcher != nullptr) {
value = other.value;
if (value > 0) {
assert(other.first == nullptr);
first = nullptr;
}
other.dispatcher = nullptr;
}
}
Latch::~Latch() {
assert(dispatcher == nullptr || value == 0 || first == nullptr);
}
Latch& Latch::operator=(Latch&& other) {
assert(dispatcher == nullptr || value == 0 || first == nullptr);
dispatcher = other.dispatcher;
if (dispatcher != nullptr) {
value = other.value;
if (value > 0) {
assert(other.first == nullptr);
first = nullptr;
}
other.dispatcher = nullptr;
}
return *this;
}
std::size_t Latch::get() const {
assert(dispatcher != nullptr);
return value;
}
void Latch::increase(std::size_t value) {
assert(dispatcher != nullptr);
if (value > 0) {
if (this->value == 0) {
first = nullptr;
}
this->value += value;
}
}
void Latch::decrease(std::size_t value) {
assert(dispatcher != nullptr);
if (value > 0) {
assert(value <= this->value);
if (this->value > 0) {
this->value -= value;
if (this->value == 0) {
for (LatchWaiter* waiter = static_cast<LatchWaiter*>(first); waiter != nullptr; waiter = waiter->next) {
dispatcher->pushContext(waiter->context);
}
}
}
}
}
void Latch::wait() {
assert(dispatcher != nullptr);
if (value > 0) {
LatchWaiter waiter = {nullptr, dispatcher->getCurrentContext()};
if (first != nullptr) {
static_cast<LatchWaiter*>(last)->next = &waiter;
} else {
first = &waiter;
}
last = &waiter;
dispatcher->dispatch();
assert(waiter.context == dispatcher->getCurrentContext());
assert(dispatcher != nullptr);
}
}
}