176 lines
5.3 KiB
C++
176 lines
5.3 KiB
C++
/*
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* nghttp2 - HTTP/2 C Library
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*
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* Copyright (c) 2012 Tatsuhiro Tsujikawa
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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#include "shrpx_downstream_queue.h"
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#include <cassert>
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#include <limits>
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#include "shrpx_downstream.h"
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namespace shrpx {
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DownstreamQueue::HostEntry::HostEntry(ImmutableString &&key)
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: key(std::move(key)), num_active(0) {}
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DownstreamQueue::DownstreamQueue(size_t conn_max_per_host, bool unified_host)
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: conn_max_per_host_(conn_max_per_host == 0
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? std::numeric_limits<size_t>::max()
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: conn_max_per_host),
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unified_host_(unified_host) {}
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DownstreamQueue::~DownstreamQueue() {
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dlist_delete_all(downstreams_);
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for (auto &p : host_entries_) {
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auto &ent = p.second;
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dlist_delete_all(ent.blocked);
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}
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}
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void DownstreamQueue::add_pending(std::unique_ptr<Downstream> downstream) {
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downstream->set_dispatch_state(DispatchState::PENDING);
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downstreams_.append(downstream.release());
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}
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void DownstreamQueue::mark_failure(Downstream *downstream) {
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downstream->set_dispatch_state(DispatchState::FAILURE);
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}
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DownstreamQueue::HostEntry &
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DownstreamQueue::find_host_entry(const StringRef &host) {
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auto itr = host_entries_.find(host);
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if (itr == std::end(host_entries_)) {
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auto key = ImmutableString{std::begin(host), std::end(host)};
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auto key_ref = StringRef{key};
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#ifdef HAVE_STD_MAP_EMPLACE
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std::tie(itr, std::ignore) =
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host_entries_.emplace(key_ref, HostEntry(std::move(key)));
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#else // !HAVE_STD_MAP_EMPLACE
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// for g++-4.7
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std::tie(itr, std::ignore) = host_entries_.insert(
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std::make_pair(key_ref, HostEntry(std::move(key))));
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#endif // !HAVE_STD_MAP_EMPLACE
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}
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return (*itr).second;
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}
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StringRef DownstreamQueue::make_host_key(const StringRef &host) const {
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return unified_host_ ? StringRef{} : host;
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}
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StringRef DownstreamQueue::make_host_key(Downstream *downstream) const {
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return make_host_key(downstream->request().authority);
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}
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void DownstreamQueue::mark_active(Downstream *downstream) {
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auto &ent = find_host_entry(make_host_key(downstream));
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++ent.num_active;
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downstream->set_dispatch_state(DispatchState::ACTIVE);
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}
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void DownstreamQueue::mark_blocked(Downstream *downstream) {
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auto &ent = find_host_entry(make_host_key(downstream));
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downstream->set_dispatch_state(DispatchState::BLOCKED);
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auto link = new BlockedLink{};
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downstream->attach_blocked_link(link);
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ent.blocked.append(link);
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}
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bool DownstreamQueue::can_activate(const StringRef &host) const {
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auto itr = host_entries_.find(make_host_key(host));
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if (itr == std::end(host_entries_)) {
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return true;
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}
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auto &ent = (*itr).second;
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return ent.num_active < conn_max_per_host_;
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}
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namespace {
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bool remove_host_entry_if_empty(const DownstreamQueue::HostEntry &ent,
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DownstreamQueue::HostEntryMap &host_entries,
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const StringRef &host) {
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if (ent.blocked.empty() && ent.num_active == 0) {
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host_entries.erase(host);
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return true;
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}
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return false;
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}
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} // namespace
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Downstream *DownstreamQueue::remove_and_get_blocked(Downstream *downstream,
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bool next_blocked) {
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// Delete downstream when this function returns.
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auto delptr = std::unique_ptr<Downstream>(downstream);
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downstreams_.remove(downstream);
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auto host = make_host_key(downstream);
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auto &ent = find_host_entry(host);
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if (downstream->get_dispatch_state() == DispatchState::ACTIVE) {
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--ent.num_active;
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} else {
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// For those downstreams deleted while in blocked state
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auto link = downstream->detach_blocked_link();
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if (link) {
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ent.blocked.remove(link);
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delete link;
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}
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}
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if (remove_host_entry_if_empty(ent, host_entries_, host)) {
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return nullptr;
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}
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if (!next_blocked || ent.num_active >= conn_max_per_host_) {
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return nullptr;
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}
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auto link = ent.blocked.head;
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if (!link) {
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return nullptr;
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}
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auto next_downstream = link->downstream;
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auto link2 = next_downstream->detach_blocked_link();
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// This is required with --disable-assert.
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(void)link2;
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assert(link2 == link);
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ent.blocked.remove(link);
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delete link;
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remove_host_entry_if_empty(ent, host_entries_, host);
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return next_downstream;
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}
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Downstream *DownstreamQueue::get_downstreams() const {
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return downstreams_.head;
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}
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} // namespace shrpx
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