Add inter-thread queue

This adds an inter-thread queue "it_q" to libosmocore. With it_q,
one can perform thread-safe enqueing of messages to another thread,
who will receive the related messages triggered via an eventfd
handled in the usual libosmocore select loop abstraction.

Change-Id: Ie7d0c5fec715a2a577fae014b0b8a0e9c38418ef

4 files changed, 145 insertions, 0 deletions

diff --git a/tests/Makefile.am b/tests/Makefile.am
index f769603f..e0220bd8 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -41,6 +41,7 @@ check_PROGRAMS = timer/timer_test sms/sms_test ussd/ussd_test		\
 		 gad/gad_test						\
 		 bsslap/bsslap_test					\
 		 bssmap_le/bssmap_le_test				\
+		 it_q/it_q_test						\
 		 $(NULL)
 
 if ENABLE_MSGFILE
@@ -304,6 +305,9 @@ bsslap_bsslap_test_LDADD = $(LDADD) $(top_builddir)/src/gsm/libosmogsm.la
 bssmap_le_bssmap_le_test_SOURCES = bssmap_le/bssmap_le_test.c
 bssmap_le_bssmap_le_test_LDADD = $(LDADD) $(top_builddir)/src/gsm/libosmogsm.la
 
+it_q_it_q_test_SOURCES = it_q/it_q_test.c
+it_q_it_q_test_LDADD = $(LDADD)
+
 # The `:;' works around a Bash 3.2 bug when the output is not writeable.
 $(srcdir)/package.m4: $(top_srcdir)/configure.ac
 	:;{ \
@@ -389,6 +393,7 @@ EXTRA_DIST = testsuite.at $(srcdir)/package.m4 $(TESTSUITE)		\
 	     gad/gad_test.ok \
 	     bsslap/bsslap_test.ok \
 	     bssmap_le/bssmap_le_test.ok \
+	     it_q/it_q_test.ok \
 	     $(NULL)
 
 if ENABLE_LIBSCTP
diff --git a/tests/it_q/it_q_test.c b/tests/it_q/it_q_test.c
new file mode 100644
index 00000000..0d754524
--- /dev/null
+++ b/tests/it_q/it_q_test.c
@@ -0,0 +1,119 @@
+#include <stdio.h>
+#include <errno.h>
+
+#include <osmocom/core/talloc.h>
+#include <osmocom/core/utils.h>
+#include <osmocom/core/it_q.h>
+
+struct it_q_test1 {
+	struct llist_head list;
+	int *foo;
+};
+
+struct it_q_test2 {
+	int foo;
+	struct llist_head list;
+};
+
+#define ENTER_TC	printf("\n== Entering test case %s\n", __func__)
+
+static void tc_alloc(void)
+{
+	struct osmo_it_q *q1, *q2;
+
+	ENTER_TC;
+
+	printf("allocating q1\n");
+	q1 = osmo_it_q_alloc(OTC_GLOBAL, "q1", 3, NULL, NULL);
+	OSMO_ASSERT(q1);
+
+	/* ensure that no duplicate allocation for the */
+	printf("attempting duplicate allocation of qa\n");
+	q2 = osmo_it_q_alloc(OTC_GLOBAL, "q1", 3, NULL, NULL);
+	OSMO_ASSERT(!q2);
+
+	/* ensure that same name can be re-created after destroying old one */
+	osmo_it_q_destroy(q1);
+	printf("re-allocating q1\n");
+	q1 = osmo_it_q_alloc(OTC_GLOBAL, "q1", 3, NULL, NULL);
+	OSMO_ASSERT(q1);
+
+	osmo_it_q_destroy(q1);
+}
+
+static void tc_queue_length(void)
+{
+	struct osmo_it_q *q1;
+	unsigned int qlen = 3;
+	struct it_q_test1 *item;
+	int i, rc;
+
+	ENTER_TC;
+
+	printf("allocating q1\n");
+	q1 = osmo_it_q_alloc(OTC_GLOBAL, "q1", qlen, NULL, NULL);
+	OSMO_ASSERT(q1);
+
+	printf("adding queue entries up to the limit\n");
+	for (i = 0; i < qlen; i++) {
+		item = talloc_zero(OTC_GLOBAL, struct it_q_test1);
+		rc = osmo_it_q_enqueue(q1, item, list);
+		OSMO_ASSERT(rc == 0);
+	}
+	printf("attempting to add more than the limit\n");
+	item = talloc_zero(OTC_GLOBAL, struct it_q_test1);
+	rc = osmo_it_q_enqueue(q1, item, list);
+	OSMO_ASSERT(rc == -ENOSPC);
+
+	osmo_it_q_destroy(q1);
+}
+
+static int g_read_cb_count;
+
+static void q_read_cb(struct osmo_it_q *q, struct llist_head *item)
+{
+	struct it_q_test1 *it = container_of(item, struct it_q_test1, list);
+	*it->foo += 1;
+	talloc_free(item);
+}
+
+static void tc_eventfd(void)
+{
+	struct osmo_it_q *q1;
+	unsigned int qlen = 30;
+	struct it_q_test1 *item;
+	int i, rc;
+
+	ENTER_TC;
+
+	printf("allocating q1\n");
+	q1 = osmo_it_q_alloc(OTC_GLOBAL, "q1", qlen, q_read_cb, NULL);
+	OSMO_ASSERT(q1);
+	osmo_fd_register(&q1->event_ofd);
+
+	/* ensure read-cb isn't called unless we enqueue something */
+	osmo_select_main(1);
+	OSMO_ASSERT(g_read_cb_count == 0);
+
+	/* ensure read-cb is called for each enqueued msg once */
+	printf("adding %u queue entries up to the limit\n", qlen);
+	for (i = 0; i < qlen; i++) {
+		item = talloc_zero(OTC_GLOBAL, struct it_q_test1);
+		item->foo = &g_read_cb_count;
+		rc = osmo_it_q_enqueue(q1, item, list);
+		OSMO_ASSERT(rc == 0);
+	}
+
+	osmo_select_main(1);
+	printf("%u entries were dequeued\n", qlen);
+	OSMO_ASSERT(g_read_cb_count == qlen);
+
+	osmo_it_q_destroy(q1);
+}
+
+int main(int argc, char **argv)
+{
+	tc_alloc();
+	tc_queue_length();
+	tc_eventfd();
+}
diff --git a/tests/it_q/it_q_test.ok b/tests/it_q/it_q_test.ok
new file mode 100644
index 00000000..7f102c61
--- /dev/null
+++ b/tests/it_q/it_q_test.ok
@@ -0,0 +1,15 @@
+
+== Entering test case tc_alloc
+allocating q1
+attempting duplicate allocation of qa
+re-allocating q1
+
+== Entering test case tc_queue_length
+allocating q1
+adding queue entries up to the limit
+attempting to add more than the limit
+
+== Entering test case tc_eventfd
+allocating q1
+adding 30 queue entries up to the limit
+30 entries were dequeued
diff --git a/tests/testsuite.at b/tests/testsuite.at
index ad93e164..75ce0393 100644
--- a/tests/testsuite.at
+++ b/tests/testsuite.at
@@ -427,3 +427,9 @@ AT_KEYWORDS([bssmap_le])
 cat $abs_srcdir/bssmap_le/bssmap_le_test.ok > expout
 AT_CHECK([$abs_top_builddir/tests/bssmap_le/bssmap_le_test], [0], [expout], [ignore])
 AT_CLEANUP
+
+AT_SETUP([it_q])
+AT_KEYWORDS([it_q])
+cat $abs_srcdir/it_q/it_q_test.ok > expout
+AT_CHECK([$abs_top_builddir/tests/it_q/it_q_test], [0], [expout], [ignore])
+AT_CLEANUP