1 files changed, 90 insertions, 0 deletions
diff --git a/src/node/warnings.h b/src/node/warnings.h
new file mode 100644
index 0000000000..24aeb8a922
--- /dev/null
+++ b/src/node/warnings.h
@@ -0,0 +1,90 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2021 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_NODE_WARNINGS_H
+#define BITCOIN_NODE_WARNINGS_H
+
+#include <sync.h>
+#include <util/translation.h>
+
+#include <map>
+#include <variant>
+#include <vector>
+
+class UniValue;
+
+namespace kernel {
+enum class Warning;
+} // namespace kernel
+
+namespace node {
+enum class Warning {
+    CLOCK_OUT_OF_SYNC,
+    PRE_RELEASE_TEST_BUILD,
+    FATAL_INTERNAL_ERROR,
+};
+
+/**
+ * @class Warnings
+ * @brief Manages warning messages within a node.
+ *
+ * The Warnings class provides mechanisms to set, unset, and retrieve
+ * warning messages. It updates the GUI when warnings are changed.
+ *
+ * This class is designed to be non-copyable to ensure warnings
+ * are managed centrally.
+ */
+class Warnings
+{
+    typedef std::variant<kernel::Warning, node::Warning> warning_type;
+
+    mutable Mutex m_mutex;
+    std::map<warning_type, bilingual_str> m_warnings GUARDED_BY(m_mutex);
+
+public:
+    Warnings();
+    //! A warnings instance should always be passed by reference, never copied.
+    Warnings(const Warnings&) = delete;
+    Warnings& operator=(const Warnings&) = delete;
+    /**
+     * @brief Set a warning message. If a warning with the specified
+     *        `id` is already active, false is returned and the new
+     *        warning is ignored. If `id` does not yet exist, the
+     *        warning is set, the UI is updated, and true is returned.
+     *
+     * @param[in]   id  Unique identifier of the warning.
+     * @param[in]   message Warning message to be shown.
+     *
+     * @returns true if the warning was indeed set (i.e. there is no
+     *          active warning with this `id`), otherwise false.
+     */
+    bool Set(warning_type id, bilingual_str message) EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);
+    /**
+     * @brief Unset a warning message. If a warning with the specified
+     *        `id` is active, it is unset, the UI is updated, and true
+     *        is returned. Otherwise, no warning is unset and false is
+     *        returned.
+     *
+     * @param[in]   id  Unique identifier of the warning.
+     *
+     * @returns true if the warning was indeed unset (i.e. there is an
+     *          active warning with this `id`), otherwise false.
+     */
+    bool Unset(warning_type id) EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);
+    /** Return potential problems detected by the node, sorted by the
+     * warning_type id */
+    std::vector<bilingual_str> GetMessages() const EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);
+};
+
+/**
+ * RPC helper function that wraps warnings.GetMessages().
+ *
+ * Returns a UniValue::VSTR with the latest warning if use_deprecated is
+ * set to true, or a UniValue::VARR with all warnings otherwise.
+ */
+UniValue GetWarningsForRpc(const Warnings& warnings, bool use_deprecated);
+} // namespace node
+
+#endif // BITCOIN_NODE_WARNINGS_H