feat(cable): add jobs.toml for managing shell background jobs

television/cable/jobs.toml

@@ -0,0 +1,57 @@
+[metadata]
+name = "jobs"
+description = """
+The current fish shell's background jobs (stopped or running). tv runs in a
+child process and cannot see the shell's job table, so the ctrl-z binding
+(_jobs_bind) writes it to the file named by $TV_JOBS; enter prints the job id
+and the binding runs `fg %<id>`; ctrl-d kills the job. Opened any other way,
+the list is empty.
+"""
+requirements = ["ps"]
+
+# Record: "%<id>  <state>  <command>", job id, process group (tab separated).
+# Newest job first, the order fish's `jobs` prints.
+[source]
+command = '[ -n "$TV_JOBS" ] && [ -r "$TV_JOBS" ] && cat "$TV_JOBS"'
+shell = "bash"
+display = "{split:\\t:0}"
+output = "{split:\\t:1}"
+
+[preview]
+command = '''
+pg='{split:\t:2}'
+# No other braces in this script: tv would read them as templates. procps
+# `ps -g` matches sessions, not process groups, so filter on pgid by hand.
+pids=$(ps -e -o pgid=,pid= --sort=start_time | while read -r g p; do [ "$g" = "$pg" ] && echo "$p"; done)
+if [ -z "$pids" ]; then
+  echo "process group $pg is gone"
+  exit 0
+fi
+first=$(echo "$pids" | head -n1)
+printf '\033[1mcwd\033[0m      %s\n' "$(readlink "/proc/$first/cwd" 2>/dev/null || echo '?')"
+printf '\033[1mstarted\033[0m  %s\n\n' "$(ps -o lstart= -p "$first" | sed 's/^ *//')"
+# STAT T = stopped (ctrl-z), S/R = running in the background.
+ps -o pid,stat,etime,pcpu,rss,args --forest -p "$(echo $pids | tr ' ' ,)"
+'''
+shell = "bash"
+
+[keybindings]
+ctrl-d = ["actions:kill", "reload_source"]
+
+# SIGTERM to the whole process group, then SIGCONT: a stopped job holds TERM
+# until it runs again. The row leaves $TV_JOBS only once the group is gone
+# (up to 1 s), so reload_source keeps a job that ignored TERM. No braces: tv
+# would read them as templates.
+[actions.kill]
+description = "Kill the job (SIGTERM to its process group)"
+command = '''
+pg='{split:\t:2}'
+kill -TERM -- "-$pg" 2>/dev/null
+kill -CONT -- "-$pg" 2>/dev/null
+for i in 1 2 3 4 5 6 7 8 9 10; do kill -0 -- "-$pg" 2>/dev/null || break; sleep 0.1; done
+if ! kill -0 -- "-$pg" 2>/dev/null && [ -w "$TV_JOBS" ]; then
+  awk -F '\t' -v g="$pg" '$3 != g' "$TV_JOBS" >"$TV_JOBS.new" && mv "$TV_JOBS.new" "$TV_JOBS"
+fi
+'''
+shell = "bash"
+mode = "fork"