Added logging support

include/countly_c.h

@@ -97,6 +97,26 @@ int countly_c_flush();
 int countly_c_end();
 
 
+/** All possible logging levels, corresponding to the internal Countly class logging levels */
+enum CountlyLogLevel
+{
+	CountlyLogLevelDebug=0,
+	CountlyLogLevelInfo=1,
+	CountlyLogLevelWarning=2,
+	CountlyLogLevelError=3,
+	CountlyLogLevelFatal=4
+};
+
+/** Logging function prototype, to be passed to countly_c_setLogFunction
+  \param level log level
+  \param message text to log
+ */
+typedef void (*countly_log_function_t)(CountlyLogLevel level, const char* message);
+
+/** Sets the logging function for all log levels */
+int countly_c_setLogFunction(countly_log_function_t logFunction);
+
+
 #ifdef __cplusplus
 }
 #endif

src/countly_c.cpp

@@ -9,20 +9,20 @@
 
 #include <countly_c.h>
 
-void onException(std::exception& e) {
-	std::cerr << std::endl << "Countly internal exception: " << e.what() << std::endl;
-	std::cerr.flush();
+#undef ERROR
+
+CountlyLogLevel mapCountlyLogLevel(Countly::LogLevel level) {
+	switch(level) {
+	case Countly::LogLevel::DEBUG:		return CountlyLogLevelDebug;
+	case Countly::LogLevel::INFO:		return CountlyLogLevelInfo;
+	case Countly::LogLevel::WARNING:	return CountlyLogLevelWarning;
+	case Countly::LogLevel::ERROR:		return CountlyLogLevelError;
+	case Countly::LogLevel::FATAL:		return CountlyLogLevelFatal;
+	default:				return CountlyLogLevelInfo;
+	}
 }
 
 
-#define COUNTLY_C_GUARD_BEGIN try {
-#define COUNTLY_C_GUARD_END } \
-	catch(std::exception& e) { \
-		onException(e); \
-		return COUNTLY_C_GENERIC_ERROR; \
-	} \
-	return COUNTLY_C_OK;
-
 
 struct CountlyCContext {
 	std::string serverHost;
@@ -31,12 +31,46 @@ struct CountlyCContext {
 
 	bool	    started=false;
 
+	countly_log_function_t logFunction = nullptr;
+
 	static CountlyCContext& get() {
 		static CountlyCContext context;
 		return context;
 	}
 };
 
+/** Default function to relay internal Countly log messages to
+ *  the user specific logging function
+ */
+void onCountlyLog(Countly::LogLevel level, const std::string& message) {
+	countly_log_function_t logFunction = CountlyCContext::get().logFunction;
+	if (logFunction != nullptr) {
+		logFunction(mapCountlyLogLevel(level), message.c_str());
+	}
+}
+
+void onException(std::exception& e) {
+	std::string logMessage = std::string("Countly internal exception: ") + e.what();
+	countly_log_function_t logFunction = CountlyCContext::get().logFunction;
+	if (logFunction != nullptr) {
+		logFunction(CountlyLogLevelError, logMessage.c_str());
+	}
+	else {
+		std::cerr << std::endl << logMessage << std::endl;
+		std::cerr.flush();
+	}
+}
+
+
+#define COUNTLY_C_GUARD_BEGIN try {
+#define COUNTLY_C_GUARD_END } \
+	catch(std::exception& e) { \
+		onException(e); \
+		return COUNTLY_C_GENERIC_ERROR; \
+	} \
+	return COUNTLY_C_OK;
+
+
 
 
 extern "C" int countly_c_init(
@@ -50,6 +84,7 @@ extern "C" int countly_c_init(
 
 	Countly& ct = Countly::getInstance();
 
+	ct.setLogger(onCountlyLog);
 	ct.SetMaxEventsPerMessage(40);
 	ct.SetPath(stateFilePath);
 
@@ -197,3 +232,12 @@ extern "C" int countly_c_end() {
 }
 
 
+extern "C" int countly_c_setLogFunction(countly_log_function_t logFunction) {
+	COUNTLY_C_GUARD_BEGIN
+
+	CountlyCContext::get().logFunction = logFunction;
+
+	COUNTLY_C_GUARD_END
+}
+
+

src/countly_c.def

@@ -7,5 +7,5 @@ EXPORTS
 	countly_c_recordEvent
 	countly_c_recordScreenView
 	countly_c_flush
-
+	countly_c_setLogFunction