Cover LoadBalancer with tests (#1394)

Fixes #680. Fixes #1222.

src/etl/NetworkValidatedLedgers.cpp

@@ -0,0 +1,65 @@
+//------------------------------------------------------------------------------
+/*
+    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 "etl/NetworkValidatedLedgers.hpp"
+
+#include <chrono>
+#include <cstdint>
+#include <memory>
+#include <mutex>
+#include <optional>
+
+namespace etl {
+std::shared_ptr<NetworkValidatedLedgers>
+NetworkValidatedLedgers::make_ValidatedLedgers()
+{
+    return std::make_shared<NetworkValidatedLedgers>();
+}
+
+void
+NetworkValidatedLedgers::push(uint32_t idx)
+{
+    std::lock_guard const lck(m_);
+    if (!max_ || idx > *max_)
+        max_ = idx;
+    cv_.notify_all();
+}
+
+std::optional<uint32_t>
+NetworkValidatedLedgers::getMostRecent()
+{
+    std::unique_lock lck(m_);
+    cv_.wait(lck, [this]() { return max_; });
+    return max_;
+}
+
+bool
+NetworkValidatedLedgers::waitUntilValidatedByNetwork(uint32_t sequence, std::optional<uint32_t> maxWaitMs)
+{
+    std::unique_lock lck(m_);
+    auto pred = [sequence, this]() -> bool { return (max_ && sequence <= *max_); };
+    if (maxWaitMs) {
+        cv_.wait_for(lck, std::chrono::milliseconds(*maxWaitMs));
+    } else {
+        cv_.wait(lck, pred);
+    }
+    return pred();
+}
+
+}  // namespace etl