I spotted this by inspection: adding a media time and wall time didn't
look right. I also confirmed the brokenness on my primary NVR:
```
sqlite> .mode column
sqlite> select
...> r1.composite_id,
...> r1.prev_media_duration_90k,
...> r1.wall_duration_90k,
...> r1.media_duration_delta_90k,
...> r2.composite_id,
...> r2.prev_media_duration_90k
...> from
...> recording r1 join recording r2 on (r1.composite_id = r2.composite_id - 1)
...> where
...> r1.prev_media_duration_90k + r1.wall_duration_90k + r1.media_duration_delta_90k !=
...> r2.prev_media_duration_90k
...> limit 5;
4296791095 2232623913716 5398956 154 4296791096 2232629312672
4296791096 2232629312672 5400016 38 4296791097 2232634712688
4296791097 2232634712688 5400729 105 4296791098 2232640113417
4296791098 2232640113417 5399024 80 4296791099 2232645512441
4296791099 2232645512441 5400770 124 4296791100 2232650913211
```
In the first row, the second recording's prev_media_duration_90k is the
first's prev_media_duration_90k plus its wall time, not its media time.
My main goal is to support creating indexes for signals as well as
recordings. An additional goal is to just shrink db.rs a bit; it's
gotten quite large.
I'm tired of all the boilerplate, so use the new
GPL-3.0-linking-exception license identifier instead in all the server
components.
I left the ui stuff alone because I'm just going to replace it (#111).
Add a checker for the header because it's easy to forget.
I want to make the project more accessible by not expecting folks to
match my idiosyncratic style. Now almost [1] everything is written
in the "standard" style. CI enforces this.
[1] "Almost": I used #[rustfmt::skip] in a few sections where I felt
aligning things in columns significantly improves readability.
Inspired by the poor error message here:
https://github.com/scottlamb/moonfire-nvr/issues/107#issuecomment-777587727
* print the friendlier Display version of the error rather than Debug.
Eg, "EROFS: Read-only filesystem" rather than "Sys(EROFS)". Do this
everywhere: on command exit, on syncer retries, and on stream
retries.
* print the most immediate problem and additional lines for each
cause.
* print the backtrace or an advertisement for RUST_BACKTRACE=1 if it's
unavailable.
* also mention RUST_BACKTRACE=1 in the troubleshooting guide.
* add context in various places, including pathnames. There are surely
many places more it'd be helpful, but this is a start.
* allow subcommands to return failure without an Error.
In particular, "moonfire-nvr check" does its own error printing
because it wants to print all the errors it finds. Printing "see
earlier errors" with a meaningless stack trace seems like it'd just
confuse. But I also want to get rid of the misleading "Success" at
the end and 0 return to the OS.
Besides being more clear about what belongs to which, this helps with
docker caching. The server and ui parts are only rebuilt when their
respective subdirectories change.
Extend this a bit further by making the webpack build not depend on
the target architecture. And adding cache dirs so parts of the server
and ui build process can be reused when layer-wide caching fails.
