feat: add foundation for configurable printer agent connection (#16027)

* feat: add foundation for configurable printer agent connection

* fix: regression after merge

* chore: remove duplcate http include

* fix: remove unrelated moonraker.cpp changes

* chore: port add_platform_root_certificates to 15711

* fix: clean diff

src/slic3r/Utils/Http.cpp

@@ -1,5 +1,6 @@
 #include "Http.hpp"
 
+#include <atomic>
 #include <cstdlib>
 #include <functional>
 #include <thread>
@@ -122,7 +123,7 @@ struct Http::priv
 	std::string error_buffer;    // Used for CURLOPT_ERRORBUFFER
     std::string headers;
 	size_t limit;
-	bool cancel;
+	std::atomic_bool cancel;
     std::unique_ptr<form_file> putFile;
 
 	std::thread io_thread;
@@ -260,9 +261,9 @@ int Http::priv::xfercb(void *userp, curl_off_t dltotal, curl_off_t dlnow, curl_o
 		self->progressfn(progress, cb_cancel);
 	}
 
-	if (cb_cancel) { self->cancel = true; }
+	if (cb_cancel) { self->cancel.store(true); }
 
-	return self->cancel;
+	return self->cancel.load();
 }
 
 int Http::priv::xfercb_legacy(void *userp, double dltotal, double dlnow, double ultotal, double ulnow)
@@ -473,7 +474,7 @@ void Http::priv::http_perform()
 
 	if (res != CURLE_OK) {
 		if (res == CURLE_ABORTED_BY_CALLBACK) {
-			if (cancel) {
+			if (cancel.load()) {
 				// The abort comes from the request being cancelled programatically
 				Progress dummyprogress(0, 0, 0, 0, std::string());
 				bool cancel = true;
@@ -784,7 +785,7 @@ void Http::perform_sync()
 
 void Http::cancel()
 {
-	if (p) { p->cancel = true; }
+	if (p) { p->cancel.store(true); }
 }
 
 void Http::print() const