Make custom exceptions visible to plugin

Generally shouldn't be required, but can't hurt.

Author: halfgaar

exceptions.h

@@ -17,18 +17,19 @@ See LICENSE for license details.
 
 #include "types.h"
 
-/*
- * Note: the exceptions here are not exposed by the compiler, that means they won't travel over DSO (plugin) boundaries.
- *
- */
+#define API __attribute__((visibility("default")))
+
+// Because exceptions are (potentially) visible to plugins, we want to make sure to avoid symbol collisions, so using their own namespace.
+namespace FlashMQ
+{
 
 /**
  * @brief The ProtocolError class is handled by the error handler in the worker threads and is used to make decisions about if and how
  * to inform a client and log the message.
  *
  * It's mainly meant for errors that can be communicated with MQTT packets.
  */
-class ProtocolError : public std::runtime_error
+class API ProtocolError : public std::runtime_error
 {
 public:
     const ReasonCodes reasonCode;
@@ -40,7 +41,7 @@ class ProtocolError : public std::runtime_error
     }
 };
 
-class BadClientException : public std::runtime_error
+class API BadClientException : public std::runtime_error
 {
     std::optional<int> mLogLevel;
 
@@ -55,41 +56,45 @@ class BadClientException : public std::runtime_error
 
 };
 
-class NotImplementedException : public std::runtime_error
+class API NotImplementedException : public std::runtime_error
 {
 public:
     NotImplementedException(const std::string &msg) : std::runtime_error(msg) {}
 };
 
-class FatalError : public std::runtime_error
+class API FatalError : public std::runtime_error
 {
 public:
     FatalError(const std::string &msg) : std::runtime_error(msg) {}
 };
 
-class ConfigFileException : public std::runtime_error
+class API ConfigFileException : public std::runtime_error
 {
 public:
     ConfigFileException(const std::string &msg) : std::runtime_error(msg) {}
     ConfigFileException(std::ostringstream oss) : std::runtime_error(oss.str()) {}
 };
 
-class pluginException : public std::runtime_error
+class API pluginException : public std::runtime_error
 {
 public:
     pluginException(const std::string &msg) : std::runtime_error(msg) {}
 };
 
-class BadWebsocketVersionException : public std::runtime_error
+class API BadWebsocketVersionException : public std::runtime_error
 {
 public:
     BadWebsocketVersionException(const std::string &msg) : std::runtime_error(msg) {}
 };
 
-class BadHttpRequest : public std::runtime_error
+class API BadHttpRequest : public std::runtime_error
 {
 public:
     BadHttpRequest(const std::string &msg) : std::runtime_error(msg) {}
 };
 
+}
+
+using namespace FlashMQ;
+
 #endif // EXCEPTIONS_H