1 files changed, 62 insertions, 0 deletions
diff --git a/include/osmocom/core/it_q.h b/include/osmocom/core/it_q.h
new file mode 100644
index 00000000..a28f524e
--- /dev/null
+++ b/include/osmocom/core/it_q.h
@@ -0,0 +1,62 @@
+#pragma once
+
+#include <osmocom/core/linuxlist.h>
+#include <osmocom/core/select.h>
+#include <pthread.h>
+
+/*! \defgroup osmo_it_q Inter-Thread Queue
+ *  @{
+ *  \file osmo_it_q.h */
+
+/*! One instance of an inter-thread queue.  The user can use this to queue messages
+ *  between different threads.  The enqueue operation is non-blocking (but of course
+ *  grabs a mutex for the actual list operations to safeguard against races).  The
+ *  receiving thread is woken up by an event_fd which can be registered in the libosmocore
+ *  select loop handling. */
+struct osmo_it_q {
+	/* entry in global list of message queues */
+	struct llist_head entry;
+
+	/* the actual list of user structs. HEAD: first in queue; TAIL: last in queue */
+	struct llist_head list;
+	/* A pthread mutex to safeguard accesses to the queue. No rwlock as we always write. */
+	pthread_mutex_t mutex;
+	/* Current count of messages in the queue */
+	unsigned int current_length;
+	/* osmo-fd wrapped eventfd */
+	struct osmo_fd event_ofd;
+
+	/* a user-defined name for this queue */
+	const char *name;
+	/* maximum permitted length of queue */
+	unsigned int max_length;
+	/* read call-back, called for each de-queued message */
+	void (*read_cb)(struct osmo_it_q *q, struct llist_head *item);
+	/* opaque data pointer passed through to call-back function */
+	void *data;
+};
+
+struct osmo_it_q *osmo_it_q_by_name(const char *name);
+
+int _osmo_it_q_enqueue(struct osmo_it_q *queue, struct llist_head *item);
+#define osmo_it_q_enqueue(queue, item, member) \
+	_osmo_it_q_enqueue(queue, &(item)->member)
+
+struct llist_head *_osmo_it_q_dequeue(struct osmo_it_q *queue);
+#define osmo_it_q_dequeue(queue, item, member) do {			\
+	struct llist_head *l = _osmo_it_q_dequeue(queue);		\
+	if (!l)								\
+		*item = NULL;						\
+	else								\
+		*item = llist_entry(l, typeof(**item), member);		\
+} while (0)
+
+
+struct osmo_it_q *osmo_it_q_alloc(void *ctx, const char *name, unsigned int max_length,
+
+					void (*read_cb)(struct osmo_it_q *q, struct llist_head *item),
+					void *data);
+void osmo_it_q_destroy(struct osmo_it_q *q);
+void osmo_it_q_flush(struct osmo_it_q *q);
+
+/*! @} */