teach libremessages:setup_traps to be able to use a custom signal handler

2 files changed, 29 insertions, 11 deletions

diff --git a/src/lib/libremessages b/src/lib/libremessages
index e5b7157..162c8fb 100755
--- a/src/lib/libremessages
+++ b/src/lib/libremessages
@@ -117,17 +117,30 @@ term_title() {
 	printf "$fmt" "$*"
 }
 
-# Usage: setup_traps
+# Usage: setup_traps [handler]
 # Sets up traps on TERM, HUP, QUIT and INT signals, as well as the ERR event,
-# similar to makepkg
+# similar to makepkg.
+#
+# If `handler` is specified, instead of using the default handler
+# (which is good for most purposes), it will call the command handler
+# with the arguments:
+#
+#   ${handler} SIGNAL_NAME MESSAGE_FMT [MESSAGE_PARAMS...]
+#
+# where MESSAGE_* are printf-like stuff.
 setup_traps() {
-	_libremessages_trap_exit() {
-		local signal=$1; shift
-		echo
-		error "$@"
-		trap -- "$signal"
-		kill "-$signal" "$$"
-	}
+	[[ $# -le 1 ]] || panic
+	if [[ $# == 1 ]]; then
+		eval "_libremessages_trap_exit() { $1 \"\$@\"; }"
+	else
+		_libremessages_trap_exit() {
+			local signal=$1; shift
+			echo
+			error "$@"
+			trap -- "$signal"
+			kill "-$signal" "$$"
+		}
+	fi
 	set -E
 	for signal in TERM HUP QUIT; do
 		trap "_libremessages_trap_exit $signal '%s signal caught. Exiting...' $signal" $signal
diff --git a/src/lib/libremessages.1.ronn b/src/lib/libremessages.1.ronn
index d4c35fc..d39dad0 100644
--- a/src/lib/libremessages.1.ronn
+++ b/src/lib/libremessages.1.ronn
@@ -69,9 +69,14 @@ Unless otherwise noted, these do not implicitly call `gettext`.
      Joins all arguments with whitespace, and sets the terminal title
      to that.
 
-   * `setup_traps`:
+   * `setup_traps` [<HANDLER>]:
      Sets traps on TERM, HUP, QUIT and INT signals, as sell as the ERR
-     event, similar to makepkg.
+     event, similar to makepkg.  If <HANDLER> is specified, instead of
+     using the default handler (which is good for most purposes), it
+     will call <HANDLER> with the arguments
+     `<HANDLER> <SIGNAL_NAME> <MESSAGE> [<MESSAGE_ARGS>...]`, where
+     <MESSAGE> is a `printf`(1)-formatted string, and <MESSAGE_ARGS>
+     are its arguments.
 
 ### PROSE ROUTINES