Add convenient error handling macros (osrf#30)

Add macros to handle java exceptions
Add macros to throw a java exception from an rcl error
Always use `base_message` instead of `message` in docblocks

Signed-off-by: Ivan Santiago Paunovic <ivanpauno@ekumenlabs.com>

Author: ivanpauno

rcljava_common/include/rcljava_common/exceptions.hpp

@@ -19,6 +19,57 @@
 
 #include "rcljava_common/visibility_control.hpp"
 
+/// Execute \a error_statement if an exception has happened.
+/**
+ * \param env a JNIEnv pointer, used to check for exceptions.
+ * \param error_statement statement executed if an exception has happened.
+ */
+#define RCLJAVA_COMMON_CHECK_FOR_EXCEPTION_WITH_ERROR_STATEMENT(env, error_statement) \
+  do { \
+    if (env->ExceptionCheck()) { \
+      error_statement; \
+    } \
+  } while (0)
+
+/// Return from the current function if a java exception has happened.
+/**
+ * \param env a JNIEnv pointer, used to check for exceptions.
+ */
+#define RCLJAVA_COMMON_CHECK_FOR_EXCEPTION(env) \
+  RCLJAVA_COMMON_CHECK_FOR_EXCEPTION_WITH_ERROR_STATEMENT(env, return )
+
+/// Call \ref rcljava_throw_rclexception if \a ret is not RCL_RET_OK,
+/// and execute \a error_statement in that case.
+/**
+ * The rcl error message will be added to \a base_message, and the rcl error state will be reset.
+ *
+ * \param env a JNIEnv pointer, used to throw a java exception from the rcl error.
+ * \param ret rcl_ret_t error that will be checked.
+ * \param base_message error message that will be passed to the thrown exception.
+ *  The complete error will be "${base_message}: ${rcl_error_string}".
+ *  \a base_message can be either a `const char *` or as `std::string`.
+ * \param error_statement statement executed if ret was not RCL_RET_OK.
+ */
+#define RCLJAVA_COMMON_THROW_FROM_RCL_WITH_ERROR_STATEMENT( \
+    env, ret, base_message, error_statement) \
+  do { \
+    if (RCL_RET_OK != ret) { \
+      rcljava_common::exceptions::rcljava_throw_rclexception( \
+        env, ret, static_cast<std::string>(base_message) + ": " + rcl_get_error_string().str); \
+      rcl_reset_error(); \
+      error_statement; \
+    } \
+  } while (0)
+
+/// Call \ref rcljava_throw_rclexception if \a ret is not RCL_RET_OK and return.
+/**
+ * \param env a JNIEnv pointer, used to check for exceptions.
+ * \param ret rcl_ret_t error that will be checked.
+ * \param base_message error message that will be passed to the thrown exception.
+ */
+#define RCLJAVA_COMMON_THROW_FROM_RCL(env, ret, base_message) \
+  RCLJAVA_COMMON_THROW_FROM_RCL_WITH_ERROR_STATEMENT(env, ret, base_message, return )
+
 namespace rcljava_common
 {
 namespace exceptions