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ext/libpqxx-7.7.3/install/ubuntu22.04/amd64/include/pqxx/errorhandler.hxx

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+/* Definition of the pqxx::errorhandler class.
+ *
+ * pqxx::errorhandler handlers errors and warnings in a database session.
+ *
+ * DO NOT INCLUDE THIS FILE DIRECTLY; include pqxx/errorhandler instead.
+ *
+ * Copyright (c) 2000-2022, Jeroen T. Vermeulen.
+ *
+ * See COPYING for copyright license.  If you did not receive a file called
+ * COPYING with this source code, please notify the distributor of this
+ * mistake, or contact the author.
+ */
+#ifndef PQXX_H_ERRORHANDLER
+#define PQXX_H_ERRORHANDLER
+
+#if !defined(PQXX_HEADER_PRE)
+#  error "Include libpqxx headers as <pqxx/header>, not <pqxx/header.hxx>."
+#endif
+
+#include "pqxx/types.hxx"
+
+
+namespace pqxx::internal::gate
+{
+class errorhandler_connection;
+}
+
+
+namespace pqxx
+{
+/**
+ * @addtogroup errorhandler
+ */
+//@{
+
+/// Base class for error-handler callbacks.
+/** To receive errors and warnings from a connection, subclass this with your
+ * own error-handler functor, and instantiate it for the connection. Destroying
+ * the handler un-registers it.
+ *
+ * A connection can have multiple error handlers at the same time.  When the
+ * database connection emits an error or warning message, it passes the message
+ * to each error handler, starting with the most recently registered one and
+ * progressing towards the oldest one.  However an error handler may also
+ * instruct the connection not to pass the message to further handlers by
+ * returning "false."
+ *
+ * @warning Strange things happen when a result object outlives its parent
+ * connection.  If you register an error handler on a connection, then you must
+ * not access the result after destroying the connection.  This applies even if
+ * you destroy the error handler first!
+ */
+class PQXX_LIBEXPORT errorhandler
+{
+public:
+  explicit errorhandler(connection &);
+  virtual ~errorhandler();
+
+  /// Define in subclass: receive an error or warning message from the
+  /// database.
+  /**
+   * @return Whether the same error message should also be passed to the
+   * remaining, older errorhandlers.
+   */
+  virtual bool operator()(char const msg[]) noexcept = 0;
+
+  errorhandler() = delete;
+  errorhandler(errorhandler const &) = delete;
+  errorhandler &operator=(errorhandler const &) = delete;
+
+private:
+  connection *m_home;
+
+  friend class internal::gate::errorhandler_connection;
+  void unregister() noexcept;
+};
+
+
+/// An error handler that suppresses any previously registered error handlers.
+class quiet_errorhandler : public errorhandler
+{
+public:
+  /// Suppress error notices.
+  quiet_errorhandler(connection &conn) : errorhandler{conn} {}
+
+  /// Revert to previous handling of error notices.
+  virtual bool operator()(char const[]) noexcept override { return false; }
+};
+
+//@}
+} // namespace pqxx
+#endif