fix: prevent stale mutation execution

src/lib/compiler.cpp

@@ -312,6 +312,11 @@ String compiler_registry_lock_file_name(Request* context)
 	return(compiler_registry_file_name(context) + ".lock");
 }
 
+String compiler_priority_file_name(Request* context)
+{
+	return(context->server->config["BIN_DIRECTORY"] + "/proactive-priority.txt");
+}
+
 int compiler_open_lock_file(String file_name, String purpose, bool nonblocking = false)
 {
 	(void)purpose;
@@ -1015,6 +1020,58 @@ bool compiler_request_can_serve_stale_artifact(Request* context)
 		float_val(context->server->config["PROACTIVE_COMPILE_CHECK_INTERVAL"]) > 0);
 }
 
+void compiler_prioritize_unit(Request* context, String file_name)
+{
+	if(!compiler_request_can_serve_stale_artifact(context))
+		return;
+	file_name = compiler_normalize_unit_path(context, file_name);
+	if(file_name == "" || file_name.find('\n') != String::npos || file_name.find('\r') != String::npos)
+		return;
+
+	String queue_file = compiler_priority_file_name(context);
+	int fd = compiler_open_lock_file(queue_file + ".lock", "proactive-priority");
+	if(fd < 0)
+		return;
+	int queue_fd = open(queue_file.c_str(), O_WRONLY | O_CREAT | O_APPEND, 0666);
+	if(queue_fd >= 0)
+	{
+		String line = file_name + "\n";
+		ssize_t offset = 0;
+		while(offset < (ssize_t)line.size())
+		{
+			ssize_t written = write(queue_fd, line.data() + offset, line.size() - offset);
+			if(written <= 0)
+				break;
+			offset += written;
+		}
+		close(queue_fd);
+	}
+	compiler_close_lock_file(fd);
+}
+
+StringList compiler_take_priority_units(Request* context)
+{
+	StringList result;
+	if(!context || !context->server)
+		return(result);
+	String queue_file = compiler_priority_file_name(context);
+	int fd = compiler_open_lock_file(queue_file + ".lock", "proactive-priority");
+	if(fd < 0)
+		return(result);
+	if(file_exists(queue_file))
+	{
+		for(auto file_name : split(file_get_contents(queue_file), "\n"))
+		{
+			file_name = trim(file_name);
+			if(file_name != "" && std::find(result.begin(), result.end(), file_name) == result.end())
+				result.push_back(file_name);
+		}
+		file_put_contents(queue_file, "");
+	}
+	compiler_close_lock_file(fd);
+	return(result);
+}
+
 void unit_render(String file_name)
 {
 	unit_render(file_name, *context);