The idea is that we have strvs like list of server names or addresses, where
the majority of strings is rather short, but some are long and there can
potentially be many strings. So formattting them either all on one line or all
in separate lines leads to output that is either hard to read or uses way too
many rows. We want to wrap them, but relying on the pager to do the wrapping is
not nice. Normal text has a lot of redundancy, so when the pager wraps a line
in the middle of a word the read can understand what is going on without any
trouble. But for a high-density zero-redundancy text like an IP address it is
much nicer to wrap between words. This also makes c&p easier.
This adds a variant of TABLE_STRV which is wrapped on output (with line breaks
inserted between different strv entries).
The change table_print() is quite ugly. A second pass is added to re-calculate
column widths. Since column size is now "soft", i.e. it can adjust based on
available columns, we need to two passes:
- first we figure out how much space we want
- in the second pass we figure out what the actual wrapped columns
widths will be.
To avoid unnessary work, the second pass is only done when we actually have
wrappable fields.
A test is added in test-format-table.
table_add_many() is so much shorter and easier to read than
table_add_cell() with its accessors. Let's teach table_add_many() more
tricks, so that reverting to table_add_cell() is not needed that often
anymore.
This adds a per-cell option for uppercasing displayed strings.
Implicitly turn this on for the header row. The fact that we format the
table header in uppercase is a formatting thing after all, hence should
be applied by the formatter, i.e. the table display code.
Moreover, this provides us with the benefit that we can more nicely
reuse the specified table headers as JSON field names, like we already
do: json field names are usually not uppercase.
This doesn't have much effect on the final build, because we link libbasic.a
into libsystemd-shared.so, so in the end, all the object built from basic/
end up in libsystemd-shared. And when the static library is linked into binaries,
any objects that are included in it but are not used are trimmed. Hence, the
size of output artifacts doesn't change:
$ du -sb /var/tmp/inst*
54181861 /var/tmp/inst1 (old)
54207441 /var/tmp/inst1s (old split-usr)
54182477 /var/tmp/inst2 (new)
54208041 /var/tmp/inst2s (new split-usr)
(The negligible change in size is because libsystemd-shared.so is bigger
by a few hundred bytes. I guess it's because symbols are named differently
or something like that.)
The effect is on the build process, in particular partial builds. This change
effectively moves the requirements on some build steps toward the leaves of the
dependency tree. Two effects:
- when building items that do not depend on libsystemd-shared, we
build less stuff for libbasic.a (which wouldn't be used anyway,
so it's a net win).
- when building items that do depend on libshared, we reduce libbasic.a as a
synchronization point, possibly allowing better parallelism.
Method:
1. copy list of .h files from src/basic/meson.build to /tmp/basic
2. $ for i in $(grep '.h$' /tmp/basic); do echo $i; git --no-pager grep "include \"$i\"" src/basic/ 'src/lib*' 'src/nss-*' 'src/journal/sd-journal.c' |grep -v "${i%.h}.c";echo ;done | less
Yu Watanabe