From b6d9ef4c7ec48a8f6cf4aaf6c3ab74bea5a77d6b Mon Sep 17 00:00:00 2001
From: Kyle Schwarz <kschwarz@intrepidcs.com>
Date: Thu, 27 Apr 2023 18:52:17 +0000
Subject: [PATCH] EventManager: Add optional debug printing

---
 README.md                      |  4 ++++
 api/icsneocpp/eventmanager.cpp | 22 ++++++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/README.md b/README.md
index 6220806..a503bde 100644
--- a/README.md
+++ b/README.md
@@ -110,6 +110,10 @@ for(size_t i = 0; i < messageCount; i++) {
 icsneo_closeDevice(myDevice);
 ```
 
+### Debugging
+
+To enable debug printing set the `LIBICSNEO_PRINT_EVENTS` environmental variable to the desired `APIEvent::Severity` level, all `Event`s greater than or equal to that level will be printed to stderr. For example, to print all warnings and errors: `LIBICSNEO_PRINT_EVENTS=32`.
+
 ## Building from Source
 ### FTD3XX
 Some devices require FTD3XX for USB communication so the [FTDI D3XX library](https://ftdichip.com/drivers/d3xx-drivers/) will be automatically downloaded and included. If you would like to use a system copy of D3XX instead you can set `FTD3XX_ROOT` to the path containing `f3d3xx.h` (`-DFTD3XX_ROOT=<path to directory containing ftd3xx.h>`).
diff --git a/api/icsneocpp/eventmanager.cpp b/api/icsneocpp/eventmanager.cpp
index 2871c44..6e6465e 100644
--- a/api/icsneocpp/eventmanager.cpp
+++ b/api/icsneocpp/eventmanager.cpp
@@ -1,5 +1,8 @@
 #include "icsneo/api/eventmanager.h"
 #include <memory>
+#include <optional>
+#include <iostream>
+#include <cstdlib>
 
 using namespace icsneo;
 
@@ -33,6 +36,25 @@ void EventManager::cancelErrorDowngradingOnCurrentThread() {
 void EventManager::add(APIEvent event) {
 	if(destructing)
 		return;
+	static const auto printLevel = []() -> std::optional<uint8_t> {
+		#ifdef _MSC_VER
+		#pragma warning(push)
+		#pragma warning(disable : 4996)
+		#endif
+		const auto level = std::getenv("LIBICSNEO_PRINT_EVENTS");
+		#ifdef _MSC_VER
+		#pragma warning(pop)
+		#endif
+		if(!level)
+			return std::nullopt;
+		try {
+			return (uint8_t)std::stoi(level);
+		} catch (std::invalid_argument const&) {
+			return std::nullopt;
+		}
+	}();
+	if(printLevel && (uint8_t)event.getSeverity() >= *printLevel)
+		std::cerr << event.describe() << std::endl;
 	if(event.getSeverity() == APIEvent::Severity::Error) {
 		// if the error was added on a thread that downgrades errors (non-user thread)
 		std::lock_guard<std::mutex> lk(downgradedThreadsMutex);