feat: server info cache (#1671)

fix: #1181

src/util/ResponseExpirationCache.cpp

@@ -0,0 +1,100 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of clio: https://github.com/XRPLF/clio
+    Copyright (c) 2024, the clio developers.
+
+    Permission to use, copy, modify, and distribute this software for any
+    purpose with or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL,  DIRECT,  INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#include "util/ResponseExpirationCache.hpp"
+
+#include "util/Assert.hpp"
+
+#include <boost/json/object.hpp>
+
+#include <chrono>
+#include <mutex>
+#include <optional>
+#include <shared_mutex>
+#include <string>
+
+namespace util {
+
+void
+ResponseExpirationCache::Entry::put(boost::json::object response)
+{
+    response_ = std::move(response);
+    lastUpdated_ = std::chrono::steady_clock::now();
+}
+
+std::optional<boost::json::object>
+ResponseExpirationCache::Entry::get() const
+{
+    return response_;
+}
+
+std::chrono::steady_clock::time_point
+ResponseExpirationCache::Entry::lastUpdated() const
+{
+    return lastUpdated_;
+}
+
+void
+ResponseExpirationCache::Entry::invalidate()
+{
+    response_.reset();
+}
+
+bool
+ResponseExpirationCache::shouldCache(std::string const& cmd)
+{
+    return cache_.contains(cmd);
+}
+
+std::optional<boost::json::object>
+ResponseExpirationCache::get(std::string const& cmd) const
+{
+    auto it = cache_.find(cmd);
+    if (it == cache_.end())
+        return std::nullopt;
+
+    auto const& entry = it->second.lock<std::shared_lock>();
+    if (std::chrono::steady_clock::now() - entry->lastUpdated() > cacheTimeout_)
+        return std::nullopt;
+
+    return entry->get();
+}
+
+void
+ResponseExpirationCache::put(std::string const& cmd, boost::json::object const& response)
+{
+    if (not shouldCache(cmd))
+        return;
+
+    ASSERT(cache_.contains(cmd), "Command is not in the cache: {}", cmd);
+
+    auto entry = cache_[cmd].lock<std::unique_lock>();
+    entry->put(response);
+}
+
+void
+ResponseExpirationCache::invalidate()
+{
+    for (auto& [_, entry] : cache_) {
+        auto entryLock = entry.lock<std::unique_lock>();
+        entryLock->invalidate();
+    }
+}
+
+}  // namespace util