# HG changeset patch
# User František Kučera <franta-hg@frantovo.cz>
# Date 1646352687 -3600
# Node ID 67898f122f53545bcda47d4a771e0877b49ffab1
# Parent  a64022f9684e3e453c694336537841351fb2606a
import PosixMQ.h from relpipe-in-posixmq

diff -r a64022f9684e -r 67898f122f53 src/PosixMQ.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/PosixMQ.h	Fri Mar 04 01:11:27 2022 +0100
@@ -0,0 +1,66 @@
+/**
+ * Relational pipes
+ * Copyright © 2022 František Kučera (Frantovo.cz, GlobalCode.info)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+#pragma once
+
+#include <mqueue.h>
+#include <string>
+#include <stdexcept>
+#include <cstring>
+
+namespace relpipe {
+namespace in {
+namespace posixmq {
+
+class PosixMQ {
+private:
+	size_t MSG_SIZE = 8192; // TODO: configurable/dynamic
+	std::string queueName;
+	mqd_t handle = -2;
+
+	PosixMQ(std::string queueName, mqd_t handle) : queueName(queueName), handle(handle) {
+	}
+
+public:
+
+	virtual ~PosixMQ() {
+		if (handle >= 0) mq_close(handle);
+	}
+
+	static PosixMQ* open(std::string queueName) {
+		mqd_t handle = mq_open(queueName.c_str(), O_RDONLY | O_CREAT);
+		if (handle >= 0) return new PosixMQ(queueName, handle);
+		else throw std::logic_error("Unable to open PosixMQ: " + queueName + " error: " + strerror(errno));
+	}
+
+	std::string receive() {
+		char buffer[MSG_SIZE + 1];
+		memset(buffer, 0, MSG_SIZE + 1);
+		ssize_t msgSize = mq_receive(handle, buffer, MSG_SIZE, nullptr);
+
+		if (msgSize >= 0) return std::string(buffer);
+		else throw std::logic_error("Unable to receive PosixMQ message from " + queueName + " error: " + strerror(errno));
+	}
+
+	void unlink() {
+		mq_unlink(queueName.c_str());
+	}
+
+};
+
+}
+}
+}