From bd5a1dc84f0124d99a89ac187f15c7d34beea210 Mon Sep 17 00:00:00 2001 From: Neels Hofmeyr Date: Mon, 28 Jan 2019 15:38:09 +0100 Subject: osmo_fsm_inst_state_chg(): set T also for zero timeout Before this patch, if timeout_secs == 0 was passed to osmo_fsm_inst_state_chg(), the previous T value remained set in the osmo_fsm_inst->T. For example: osmo_fsm_inst_state_chg(fi, ST_X, 23, 42); // timer == 23 seconds; fi->T == 42 osmo_fsm_inst_state_chg(fi, ST_Y, 0, 0); // no timer; fi->T == 42! Instead, always set to the T value passed to osmo_fsm_inst_state_chg(). Adjust osmo_fsm_inst_state_chg() API doc; need to rephrase to accurately describe the otherwise unchanged behaviour independently from T. Verify in fsm_test.c. Rationale: it is confusing to have a T number remaining from some past state, especially since the user explicitly passed a T number to osmo_fsm_inst_state_chg(). (Usually we are passing timeout_secs=0, T=0). I first thought this behavior was introduced with osmo_fsm_inst_state_chg_keep_timer(), but in fact osmo_fsm_inst_state_chg() behaved this way from the start. This shows up in the C test for the upcoming tdef API, where the test result printout was showing some past T value sticking around after FSM state transitions. After this patch, there will be no such confusion. Change-Id: I65c7c262674a1bc5f37faeca6aa0320ab0174f3c --- src/fsm.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) (limited to 'src/fsm.c') diff --git a/src/fsm.c b/src/fsm.c index 1f6141fa..ae7c0f53 100644 --- a/src/fsm.c +++ b/src/fsm.c @@ -458,9 +458,10 @@ static int state_chg(struct osmo_fsm_inst *fi, uint32_t new_state, fi->state = new_state; st = &fsm->states[new_state]; - if (!keep_timer && timeout_secs) { + if (!keep_timer) { fi->T = T; - osmo_timer_schedule(&fi->timer, timeout_secs, 0); + if (timeout_secs) + osmo_timer_schedule(&fi->timer, timeout_secs, 0); } /* Call 'onenter' last, user might terminate FSM from there */ @@ -480,11 +481,17 @@ static int state_chg(struct osmo_fsm_inst *fi, uint32_t new_state, * function. It verifies that the existing state actually permits a * transition to new_state. * - * timeout_secs and T are optional parameters, and only have any effect - * if timeout_secs is not 0. If the timeout function is used, then the - * new_state is entered, and the FSM instances timer is set to expire - * in timeout_secs functions. At that time, the FSM's timer_cb - * function will be called for handling of the timeout by the user. + * If timeout_secs is 0, stay in the new state indefinitely, without a timeout + * (stop the FSM instance's timer if it was runnning). + * + * If timeout_secs > 0, start or reset the FSM instance's timer with this + * timeout. On expiry, invoke the FSM instance's timer_cb -- if no timer_cb is + * set, an expired timer immediately terminates the FSM instance with + * OSMO_FSM_TERM_TIMEOUT. + * + * The value of T is stored in fi->T and is then available for query in + * timer_cb. If passing timeout_secs == 0, it is recommended to also pass T == + * 0, so that fi->T is reset to 0 when no timeout is invoked. * * \param[in] fi FSM instance whose state is to change * \param[in] new_state The new state into which we should change -- cgit v1.2.3