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Diffstat (limited to '')
-rw-r--r-- | delaypipe.hh | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/delaypipe.hh b/delaypipe.hh new file mode 100644 index 0000000..ad1626a --- /dev/null +++ b/delaypipe.hh @@ -0,0 +1,85 @@ +/* + * This file is part of PowerDNS or dnsdist. + * Copyright -- PowerDNS.COM B.V. and its contributors + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of version 2 of the GNU General Public License as + * published by the Free Software Foundation. + * + * In addition, for the avoidance of any doubt, permission is granted to + * link this program with OpenSSL and to (re)distribute the binaries + * produced as the result of such linking. + * + * 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, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ +#pragma once +#include <map> +#include <time.h> +#include <thread> + +/** + General idea: many threads submit work to this class, but only one executes it. The work should therefore be entirely trivial. + The implementation is that submitter threads create an object that represents the work, and it gets sent over a pipe + to the worker thread. + + The worker thread meanwhile listens on this pipe (non-blocking), with a delay set to the next object that needs to be executed. + If meanwhile new work comes in, all objects who's time has come are executed, a new sleep time is calculated. +*/ + + +/* ObjectPipe facilitates the type-safe passing of types over a pipe */ + +template<class T> +class ObjectPipe +{ +public: + ObjectPipe(); + ~ObjectPipe(); + void write(T& t); + int readTimeout(T* t, double msec); //!< -1 is timeout, 0 is no data, 1 is data. msec<0 waits infinitely long. msec==0 = undefined + void close(); +private: + int d_fds[2]; +}; + +template<class T> +class DelayPipe +{ +public: + DelayPipe(); + ~DelayPipe(); + void submit(T& t, int msec); //!< don't try for more than 4294 msec + +private: + void worker(); + struct Combo + { + T what; + struct timespec when; + }; + + double tsdelta(const struct timespec& a, const struct timespec& b) // read as a-b + { + return 1.0*(a.tv_sec-b.tv_sec)+1.0*(a.tv_nsec-b.tv_nsec)/1000000000.0; + } + + ObjectPipe<Combo> d_pipe; + struct tscomp { + bool operator()(const struct timespec& a, const struct timespec& b) const + { + return std::tie(a.tv_sec, a.tv_nsec) < std::tie(b.tv_sec, b.tv_nsec); + } + }; + std::multimap<struct timespec, T, tscomp> d_work; + void gettime(struct timespec* ts); + std::thread d_thread; +}; + +#include "delaypipe.cc" |