fcb8d040e8
Instead of lengthy blurbs, switch to single-line, machine-readable standardized (https://spdx.dev) license identifiers. The Linux kernel switched long ago, so there is strong precedent. Three cases are handled: AGPL-only, Apache-only, and dual licensed. For the latter case, I chose (AGPL-3.0-or-later and Apache-2.0), reasoning that our changes are extensive enough to apply our license. The changes we applied mechanically with a script, except to licenses/README.md. Closes #9937
110 lines
2.9 KiB
C++
110 lines
2.9 KiB
C++
/*
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* Copyright (C) 2015-present ScyllaDB
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*/
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/*
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* SPDX-License-Identifier: AGPL-3.0-or-later
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*/
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#pragma once
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#include "clocks-impl.hh"
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#include "hashing.hh"
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#include <seastar/core/lowres_clock.hh>
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#include <chrono>
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#include <optional>
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class gc_clock final {
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public:
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using base = seastar::lowres_system_clock;
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using rep = int64_t;
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using period = std::ratio<1, 1>; // seconds
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using duration = std::chrono::duration<rep, period>;
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using time_point = std::chrono::time_point<gc_clock, duration>;
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static constexpr auto is_steady = base::is_steady;
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static constexpr std::time_t to_time_t(time_point t) {
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return std::chrono::duration_cast<std::chrono::seconds>(t.time_since_epoch()).count();
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}
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static constexpr time_point from_time_t(std::time_t t) {
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return time_point(std::chrono::duration_cast<duration>(std::chrono::seconds(t)));
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}
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static time_point now() {
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return time_point(std::chrono::duration_cast<duration>(base::now().time_since_epoch())) + get_clocks_offset();
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}
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static int32_t as_int32(duration d) {
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auto count = d.count();
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int32_t count_32 = static_cast<int32_t>(count);
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if (count_32 != count) {
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throw std::runtime_error("Duration too big");
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}
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return count_32;
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}
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static int32_t as_int32(time_point tp) {
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return as_int32(tp.time_since_epoch());
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}
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};
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using expiry_opt = std::optional<gc_clock::time_point>;
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using ttl_opt = std::optional<gc_clock::duration>;
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// 20 years in seconds
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static constexpr gc_clock::duration max_ttl = gc_clock::duration{20 * 365 * 24 * 60 * 60};
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std::ostream& operator<<(std::ostream& os, gc_clock::time_point tp);
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template<>
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struct appending_hash<gc_clock::time_point> {
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template<typename Hasher>
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void operator()(Hasher& h, gc_clock::time_point t) const {
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// Remain backwards-compatible with the 32-bit duration::rep (refs #4460).
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uint64_t d64 = t.time_since_epoch().count();
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feed_hash(h, uint32_t(d64 & 0xffff'ffff));
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uint32_t msb = d64 >> 32;
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if (msb) {
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feed_hash(h, msb);
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}
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}
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};
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namespace ser {
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// Forward-declaration - defined in serializer.hh, to avoid including it here.
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template <typename Output>
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void serialize_gc_clock_duration_value(Output& out, int64_t value);
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template <typename Input>
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int64_t deserialize_gc_clock_duration_value(Input& in);
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template <typename T>
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struct serializer;
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template <>
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struct serializer<gc_clock::duration> {
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template <typename Input>
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static gc_clock::duration read(Input& in) {
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return gc_clock::duration(deserialize_gc_clock_duration_value(in));
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}
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template <typename Output>
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static void write(Output& out, gc_clock::duration d) {
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serialize_gc_clock_duration_value(out, d.count());
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}
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template <typename Input>
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static void skip(Input& in) {
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read(in);
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}
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};
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}
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