system/uorb: fix listener_top not showing topic data

[Zepp-Hanzj]

Note: Please adhere to Contributing Guidelines.

Summary

uorb_listener -T (top mode) only displays the header row but no topic data. This is because listener_update() only prints topic data when delta_generation && delta_time is true (new data arrived since the last check). On the first iteration, objects are added to the list but no data is printed. On subsequent iterations, if no new data has been published between calls, delta_generation == 0 and the topic row is silently skipped.

Fix by moving the uorbinfo_raw() call and timestamp/generation update outside the conditional block, and initializing frequency = 0 before the check. This ensures the topic row is always printed, with frequency showing 0 when no new data is available.

Fixes apache/nuttx-apps#3202.

Impact

• Is new feature?: NO (bug fix)
• Impact on user?: YES (users can now see topic data in uorb_listener -T top mode)
• Impact on build?: NO
• Impact on hardware?: NO
• Impact on documentation?: NO
• Impact on security?: NO
• Impact on compatibility?: NO

Testing

Host: Linux x86_64, sim:nsh

Config:

CONFIG_USENSOR=y
CONFIG_UORB=y
CONFIG_UORB_LISTENER=y
CONFIG_UORB_GENERATOR=y
CONFIG_SENSORS=y
CONFIG_SENSORS_FAKESENSOR=y
CONFIG_DEBUG_UORB=y
CONFIG_LINE_MAX=256
CONFIG_NSH_MAXARGUMENTS=16

Steps:

nsh> uorb_generator -n 100000 -r 10 -s -t sensor_accel0 timestamp:1,x:1,y:1,z:1,temperature:1 &
nsh> sleep 3
nsh> uorb_listener -T -l

Before fix:

current objects: 1
NAME                           INST #SUB RATE #Q SIZE

After fix:

current objects: 1
NAME                           INST #SUB RATE #Q SIZE
sensor_accel                    0    0    8  1   24

[linguini1]

When I try to compile your configuration I get this error:

CP:  /home/linguini/coding/nuttx-space/nuttx/include/nuttx/config.h
CC:  grp/lib_getgrbuf.c generator.c: In function ‘replay_worker’:
generator.c:205:44: error: ‘const struct orb_metadata’ has no member named ‘o_format’
  205 |                        sensor_gen->obj.meta->o_format, data);
      |                                            ^~
generator.c: In function ‘fake_worker’:
generator.c:287:38: error: ‘const struct orb_metadata’ has no member named ‘o_format’
  287 |                  sensor_gen->obj.meta->o_format, data) < 0)
      |                                      ^~
make[2]: *** [/home/linguini/coding/nuttx-space/apps/Application.mk:330: generator.c.home.linguini.coding.nuttx-space.apps.system.uorb.o] Error 1
make[2]: *** Waiting for unfinished jobs....
IN: mm/libmm.a -> staging/libmm.a make[1]: *** [Makefile:54: /home/linguini/coding/nuttx-space/apps/system/uorb_all] Error 2
make[1]: *** Waiting for unfinished jobs....
CC:  pthread/pthread_mutexattr_setpshared.c make: *** [tools/LibTargets.mk:248: /home/linguini/coding/nuttx-space/apps/libapps.a] Error 2
make: *** Waiting for unfinished jobs....

[Zepp-Hanzj]

When I try to compile your configuration I get this error:

CP:  /home/linguini/coding/nuttx-space/nuttx/include/nuttx/config.h
CC:  grp/lib_getgrbuf.c generator.c: In function ‘replay_worker’:
generator.c:205:44: error: ‘const struct orb_metadata’ has no member named ‘o_format’
  205 |                        sensor_gen->obj.meta->o_format, data);
      |                                            ^~
generator.c: In function ‘fake_worker’:
generator.c:287:38: error: ‘const struct orb_metadata’ has no member named ‘o_format’
  287 |                  sensor_gen->obj.meta->o_format, data) < 0)
      |                                      ^~
make[2]: *** [/home/linguini/coding/nuttx-space/apps/Application.mk:330: generator.c.home.linguini.coding.nuttx-space.apps.system.uorb.o] Error 1
make[2]: *** Waiting for unfinished jobs....
IN: mm/libmm.a -> staging/libmm.a make[1]: *** [Makefile:54: /home/linguini/coding/nuttx-space/apps/system/uorb_all] Error 2
make[1]: *** Waiting for unfinished jobs....
CC:  pthread/pthread_mutexattr_setpshared.c make: *** [tools/LibTargets.mk:248: /home/linguini/coding/nuttx-space/apps/libapps.a] Error 2
make: *** Waiting for unfinished jobs....

Sorry for the oversight. The compilation error occurs because generator.c uses o_format to parse sensor data from stdin, but CONFIG_UORB_FORMAT wasn't being selected when only UORB_GENERATOR was enabled.
Fixed by adding select UORB_FORMAT to UORB_GENERATOR in Kconfig. Verified locally:
Only UORB enabled → UORB_FORMAT not selected (no overhead)
UORB_GENERATOR enabled → UORB_FORMAT auto-selected, build passes
Thanks for catching this!

[Zepp-Hanzj]

I must sleep. It's 0:11 now in my zone.

[linguini1]

Do you mean UORB_DEBUG instead of UORB_FORMAT? I don't think UORB_FORMAT exists. We should probably fix the compilation error by default, that seems confusing.

Anyways, with your updated config option list I was able to reproduce your results!

[Zepp-Hanzj]

By the way, I wrote a tool — a WinDirStat-style treemap UI combined with MAP/ELF symbol and memory layout analysis for Windows. Not sure if it'd be useful for analyzing space usage in the NuttX project. https://github.com/Zepp-Hanzj/MemMapExplorer