117 lines
4.1 KiB
C++
117 lines
4.1 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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#ifndef SHRPX_DOWNSTREAM_QUEUE_H
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#define SHRPX_DOWNSTREAM_QUEUE_H
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#include "shrpx.h"
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#include <cinttypes>
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#include <map>
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#include <set>
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#include <memory>
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#include "template.h"
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using namespace nghttp2;
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namespace shrpx {
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class Downstream;
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// Link entry in HostEntry.blocked and downstream because downstream
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// could be deleted in anytime and we'd like to find Downstream in
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// O(1). Downstream has field to link back to this object.
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struct BlockedLink {
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Downstream *downstream;
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BlockedLink *dlnext, *dlprev;
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};
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class DownstreamQueue {
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public:
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struct HostEntry {
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HostEntry(ImmutableString &&key);
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HostEntry(HostEntry &&) = default;
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HostEntry &operator=(HostEntry &&) = default;
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HostEntry(const HostEntry &) = delete;
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HostEntry &operator=(const HostEntry &) = delete;
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// Key that associates this object
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ImmutableString key;
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// Set of stream ID that blocked by conn_max_per_host_.
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DList<BlockedLink> blocked;
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// The number of connections currently made to this host.
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size_t num_active;
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};
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using HostEntryMap = std::map<StringRef, HostEntry>;
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// conn_max_per_host == 0 means no limit for downstream connection.
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DownstreamQueue(size_t conn_max_per_host = 0, bool unified_host = true);
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~DownstreamQueue();
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// Add |downstream| to this queue. This is entry point for
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// Downstream object.
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void add_pending(std::unique_ptr<Downstream> downstream);
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// Set |downstream| to failure state, which means that downstream
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// failed to connect to backend.
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void mark_failure(Downstream *downstream);
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// Set |downstream| to active state, which means that downstream
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// connection has started.
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void mark_active(Downstream *downstream);
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// Set |downstream| to blocked state, which means that download
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// connection was blocked because conn_max_per_host_ limit.
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void mark_blocked(Downstream *downstream);
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// Returns true if we can make downstream connection to given
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// |host|.
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bool can_activate(const StringRef &host) const;
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// Removes and frees |downstream| object. If |downstream| is in
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// DispatchState::ACTIVE, and |next_blocked| is true, this function
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// may return Downstream object with the same target host in
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// DispatchState::BLOCKED if its connection is now not blocked by
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// conn_max_per_host_ limit.
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Downstream *remove_and_get_blocked(Downstream *downstream,
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bool next_blocked = true);
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Downstream *get_downstreams() const;
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HostEntry &find_host_entry(const StringRef &host);
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StringRef make_host_key(const StringRef &host) const;
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StringRef make_host_key(Downstream *downstream) const;
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private:
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// Per target host structure to keep track of the number of
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// connections to the same host.
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HostEntryMap host_entries_;
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DList<Downstream> downstreams_;
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// Maximum number of concurrent connections to the same host.
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size_t conn_max_per_host_;
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// true if downstream host is treated as the same. Used for reverse
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// proxying.
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bool unified_host_;
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};
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} // namespace shrpx
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#endif // SHRPX_DOWNSTREAM_QUEUE_H
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