beremiz

SVGHMI: ensures that PLC sends only fresh data to HMI, even right after variable being subscribed.

2022-09-14, Edouard Tisserant
7af7a23e4adb
Parents be87303d5b2d
Children da020d88db0c0e0252339e83
SVGHMI: ensures that PLC sends only fresh data to HMI, even right after variable being subscribed.
1 files changed, 29 insertions(+), 20 deletions(-)
  • +29 -20
    svghmi/svghmi.c
    • --- a/svghmi/svghmi.c Tue Sep 13 16:31:52 2022 +0200
    +++ b/svghmi/svghmi.c Wed Sep 14 12:41:44 2022 +0200
    @@ -103,12 +103,14 @@
    void *dest_p = NULL;
    void *value_p = NULL;
    size_t sz = 0;
    + int do_sample = 0;
    while(session_index < MAX_CONNECTIONS) {
    if(dsc->wstate[session_index] == buf_set){
    /* if being subscribed */
    if(dsc->refresh_period_ms[session_index]){
    - if(dsc->age_ms[session_index] + ticktime_ms < dsc->refresh_period_ms[session_index]){
    - dsc->age_ms[session_index] += ticktime_ms;
    + uint16_t new_age_ms = dsc->age_ms[session_index] + ticktime_ms;
    + if(new_age_ms < dsc->refresh_period_ms[session_index]){
    + dsc->age_ms[session_index] = new_age_ms;
    }else{
    dsc->wstate[session_index] = buf_tosend;
    global_write_dirty = 1;
    @@ -116,33 +118,30 @@
    }
    }
    - /* variable is sample only if just subscribed
    + /* variable is sampled if just subscribed (initial value)
    or already subscribed and having value change */
    - int do_sample = 0;
    + int sample_session = 0;
    int just_subscribed = dsc->wstate[session_index] == buf_new;
    - if(!just_subscribed){
    + if(just_subscribed){
    + sample_session = 1;
    + } else {
    int already_subscribed = dsc->refresh_period_ms[session_index] > 0;
    if(already_subscribed){
    - if(!value_changed){
    - if(!value_p){
    - UnpackVar(dsc, &value_p, NULL, &sz);
    - if(__Is_a_string(dsc)){
    - sz = ((STRING*)value_p)->len + 1;
    - }
    - dest_p = &wbuf[dsc->buf_index];
    + /* compute value_changed once only */
    + if(!value_p){
    + UnpackVar(dsc, &value_p, NULL, &sz);
    + if(__Is_a_string(dsc)){
    + sz = ((STRING*)value_p)->len + 1;
    }
    + dest_p = &wbuf[dsc->buf_index];
    value_changed = memcmp(dest_p, value_p, sz) != 0;
    - do_sample = value_changed;
    - }else{
    - do_sample = 1;
    }
    + sample_session = value_changed;
    }
    - } else {
    - do_sample = 1;
    }
    - if(do_sample){
    + if(sample_session){
    if(dsc->wstate[session_index] != buf_set && dsc->wstate[session_index] != buf_tosend) {
    if(dsc->wstate[session_index] == buf_new \
    || ticktime_ms > dsc->refresh_period_ms[session_index]){
    @@ -153,13 +152,23 @@
    }
    dsc->age_ms[session_index] = 0;
    }
    + do_sample = 1;
    }
    session_index++;
    }
    - /* copy value if changed (and subscribed) */
    - if(value_changed)
    +
    + /* copy value if one at least one session did sample */
    + if(do_sample){
    + if(!value_p){
    + UnpackVar(dsc, &value_p, NULL, &sz);
    + if(__Is_a_string(dsc)){
    + sz = ((STRING*)value_p)->len + 1;
    + }
    + dest_p = &wbuf[dsc->buf_index];
    + }
    memcpy(dest_p, value_p, sz);
    + }
    return 0;
    }