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construct/matrix/gossip.cc

139 lines
2.8 KiB
C++

// The Construct
//
// Copyright (C) The Construct Developers, Authors & Contributors
// Copyright (C) 2016-2020 Jason Volk <jason@zemos.net>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice is present in all copies. The
// full license for this software is available in the LICENSE file.
decltype(ircd::m::gossip::log)
ircd::m::gossip::log
{
"m.gossip"
};
/// Initial gossip protocol works by sending the remote server some events which
/// reference an event contained in the remote's head which we just obtained.
/// This is part of a family of active measures taken to reduce forward
/// extremities on other servers but without polluting the chain with
/// permanent data for this purpose such as with org.matrix.dummy_event.
ircd::m::gossip::gossip::gossip(const room::id &room_id,
const opts &opts)
{
assert(opts.event_id);
const auto &event_id
{
opts.event_id
};
const m::event::refs refs
{
m::index(std::nothrow, event_id)
};
static const size_t max{48};
const size_t count
{
std::min(refs.count(dbs::ref::NEXT), max)
};
if(!count)
return;
const unique_mutable_buffer buf[]
{
{ event::MAX_SIZE * (count + 1) },
{ 16_KiB },
};
size_t i{0};
std::array<event::idx, max> next_idx;
refs.for_each(dbs::ref::NEXT, [&next_idx, &i]
(const event::idx &event_idx, const auto &ref_type)
{
assert(ref_type == dbs::ref::NEXT);
next_idx.at(i) = event_idx;
return ++i < next_idx.size();
});
size_t ret{0};
json::stack out{buf[0]};
{
json::stack::object top
{
out
};
json::stack::member
{
top, "origin", m::my_host()
};
json::stack::member
{
top, "origin_server_ts", json::value
{
long(ircd::time<milliseconds>())
}
};
json::stack::array pdus
{
top, "pdus"
};
m::event::fetch event;
for(assert(ret == 0); ret < i; ++ret)
if(seek(std::nothrow, event, next_idx.at(ret)))
pdus.append(event.source);
}
const string_view txn
{
out.completed()
};
char idbuf[64];
const string_view txnid
{
m::txn::create_id(idbuf, txn)
};
m::fed::send::opts fedopts;
fedopts.remote = opts.remote;
m::fed::send request
{
txnid, txn, buf[1], std::move(fedopts)
};
http::code code{0};
std::exception_ptr eptr;
if(request.wait(opts.timeout, std::nothrow)) try
{
code = request.get();
ret += code == http::OK;
}
catch(...)
{
eptr = std::current_exception();
}
log::logf
{
log, code == http::OK? log::DEBUG : log::DERROR,
"gossip %zu:%zu to %s reference to %s in %s :%s %s",
ret,
count,
opts.remote,
string_view{event_id},
string_view{room_id},
code?
status(code):
"failed",
eptr?
what(eptr):
string_view{},
};
}