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/*
* ZeroTier One - Network Virtualization Everywhere
* Copyright (C) 2011-2016 ZeroTier, Inc. https://www.zerotier.com/
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "OSUtils.hpp"
#include "Thread.hpp"
#include "BackgroundResolver.hpp"
namespace ZeroTier {
/*
* We can't actually abort a job. This is a legacy characteristic of the
* ancient synchronous resolver APIs. So to abort jobs, we just abandon
* them by setting their parent to null.
*/
class BackgroundResolverJob
{
public:
std::string name;
BackgroundResolver *volatile parent;
Mutex lock;
void threadMain()
throw()
{
std::vector<InetAddress> ips;
try {
ips = OSUtils::resolve(name.c_str());
} catch ( ... ) {}
{
Mutex::Lock _l(lock);
BackgroundResolver *p = parent;
if (p)
p->_postResult(ips);
}
delete this;
}
};
BackgroundResolver::BackgroundResolver(const char *name) :
_name(name),
_job((BackgroundResolverJob *)0),
_callback(0),
_arg((void *)0),
_ips(),
_lock()
{
}
BackgroundResolver::~BackgroundResolver()
{
abort();
}
std::vector<InetAddress> BackgroundResolver::get() const
{
Mutex::Lock _l(_lock);
return _ips;
}
void BackgroundResolver::resolveNow(void (*callback)(BackgroundResolver *,void *),void *arg)
{
Mutex::Lock _l(_lock);
if (_job) {
Mutex::Lock _l2(_job->lock);
_job->parent = (BackgroundResolver *)0;
_job = (BackgroundResolverJob *)0;
}
BackgroundResolverJob *j = new BackgroundResolverJob();
j->name = _name;
j->parent = this;
_job = j;
_callback = callback;
_arg = arg;
_jobThread = Thread::start(j);
}
void BackgroundResolver::abort()
{
Mutex::Lock _l(_lock);
if (_job) {
Mutex::Lock _l2(_job->lock);
_job->parent = (BackgroundResolver *)0;
_job = (BackgroundResolverJob *)0;
}
}
void BackgroundResolver::_postResult(const std::vector<InetAddress> &ips)
{
void (*cb)(BackgroundResolver *,void *);
void *a;
{
Mutex::Lock _l(_lock);
_job = (BackgroundResolverJob *)0;
cb = _callback;
a = _arg;
_ips = ips;
}
if (cb)
cb(this,a);
}
} // namespace ZeroTier
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