diff options
Diffstat (limited to 'mail-overview/mail-notify.sh')
| -rwxr-xr-x | mail-overview/mail-notify.sh | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/mail-overview/mail-notify.sh b/mail-overview/mail-notify.sh index ed0c3e3..3e28bab 100755 --- a/mail-overview/mail-notify.sh +++ b/mail-overview/mail-notify.sh @@ -110,6 +110,43 @@ build_body() { printf '\n' } +# The last revision this script notified up to, or empty when there is none +# to trust. Empty means "seed silently": record where we are now and notify +# nothing. +# +# The stored UUID is checked because notmuch revisions are only comparable +# within one database. A rebuilt database restarts the counter, so an old +# revision would be meaningless, and treating it as a floor would either +# notify nothing forever or notify everything at once. +read_prev_rev() { + local want_uuid="$1" got_uuid rev + + [[ -f "$STATE" ]] || return 0 + read -r got_uuid rev < "$STATE" 2>/dev/null || return 0 + + [[ "$got_uuid" == "$want_uuid" ]] || return 0 + [[ "$rev" =~ ^[0-9]+$ ]] || return 0 + + printf '%s' "$rev" +} + +# Written by atomic replace, the same idiom mail-watcher uses for its +# heartbeat: a reader must never see a half-written file, and mv within a +# directory is atomic where a redirect into the final path is not. +# +# Failure to write is deliberately not fatal. The notifications have already +# been sent; taking the watcher down over a failure to record that would turn +# a bookkeeping problem into a no-mail-notifications problem. +write_state() { + local uuid="$1" rev="$2" tmp + + mkdir -p "$(dirname "$STATE")" 2>/dev/null || return 0 + tmp="$(mktemp "${STATE}.XXXXXX")" || return 0 + printf '%s %s\n' "$uuid" "$rev" > "$tmp" || { rm -f "$tmp"; return 0; } + mv -f "$tmp" "$STATE" 2>/dev/null || rm -f "$tmp" + return 0 +} + main() { echo "not implemented" } |