Arrange new method for writing command wrappers

4 files changed, 76 insertions, 37 deletions

diff --git a/.local/bin/signal b/.local/bin/signal
index bf8d198..3dc73e2 100755..120000
--- a/.local/bin/signal
+++ b/.local/bin/signal
@@ -1,37 +1 @@
-#!/bin/sh
-
-# This program is free software: you can redistribute it and/or modify it under
-# the terms of the GNU Affero General Public License as published by the Free
-# Software Foundation, either version 3 of the License, or (at your option) any
-# later version.
-#
-# This program is distributed in the hope that it will be useful, but WITHOUT
-# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
-# FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
-# details.
-
-readonly BINS="
-	/usr/bin/signal-desktop
-"
-
-main()
-{
-	for bin in $BINS
-	do
-		[ -x "$bin" ] || continue
-
-		export TMPDIR="${XDG_CACHE_HOME:-$HOME/.local/tmp}"
-		mkdir -p -- "/run/user/$UID/doc/by-app/org.signal.Signal"
-
-		exec "$bin" "$@"
-	done
-
-	printf "No underlying executable found for %s:\n" "${0##*/}" >&2
-
-	for bin in $BINS
-	do
-		printf "\t%s\n" "$bin" >&2
-	done
-}
-
-main "$@"
+../lib/cmd-wrapper/wrapper.sh
\ No newline at end of file
diff --git a/.local/etc/cmd-wrapper/signal/bins.txt b/.local/etc/cmd-wrapper/signal/bins.txt
new file mode 100644
index 0000000..a5262d1
--- /dev/null
+++ b/.local/etc/cmd-wrapper/signal/bins.txt
@@ -0,0 +1 @@
+/usr/bin/signal-desktop
diff --git a/.local/etc/cmd-wrapper/signal/env.sh b/.local/etc/cmd-wrapper/signal/env.sh
new file mode 100644
index 0000000..8d3399d
--- /dev/null
+++ b/.local/etc/cmd-wrapper/signal/env.sh
@@ -0,0 +1,6 @@
+#!/bin/sh
+
+wrap_before() {
+	export TMPDIR="${XDG_CACHE_HOME:-$HOME/.local/tmp}"
+	mkdir -p -- "/run/user/$UID/doc/by-app/org.signal.Signal"
+}
diff --git a/.local/lib/cmd-wrapper/wrapper.sh b/.local/lib/cmd-wrapper/wrapper.sh
new file mode 100755
index 0000000..de74794
--- /dev/null
+++ b/.local/lib/cmd-wrapper/wrapper.sh
@@ -0,0 +1,68 @@
+#!/bin/sh
+
+# This program is free software: you can redistribute it and/or modify it under
+# the terms of the GNU Affero General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or (at your option) any
+# later version.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+# details.
+
+readonly wrapper_name="${0##*/}"
+readonly wrapper_data="$HOME/.local/etc/cmd-wrapper/${0##*/}"
+
+main() {
+	# Ensure there's a text file containing a list of potential binaries
+	if [ ! -f "$wrapper_data/bins.txt" ]
+	then
+		printf "No wrapper bins for %s (%s)\n" \
+			"$wrapper_name" \
+			"$wrapper_data/bins.txt" \
+			>&2
+
+		exit 1
+	fi
+
+	# Source a custom environment if one exists
+	if [ -f "$wrapper_data/env.sh" ]
+	then
+		#shellcheck disable=1090
+		. "$wrapper_data/env.sh"
+	fi
+
+	# Loop through all potential binaries
+	while read -r bin
+	do
+		# Check if this particular bin is available
+		[ -x "$bin" ] || continue
+
+		# Run the wrap_before command if specified
+		if command -V "wrap_before" 2>/dev/null | head -n 1 | grep -Eq "function$"
+		then
+			wrap_before
+		fi
+
+		# shellcheck disable=SC2093
+		wrap_cmd "$bin" "$@"
+	done < "$wrapper_data/bins.txt"
+
+	# No fitting binary found, show error
+	printf "None of the underlying executables for %s exist:\n" \
+		"$wrapper_name" >&2
+
+	while read -r bin
+	do
+		printf "\t%s\n" "$bin" >&2
+	done < "$wrapper_data/bins.txt"
+
+	exit 1
+}
+
+# The actual running of the binary can be overriden from an env.sh, if desired.
+wrap_cmd() {
+	exec "$@"
+}
+
+main "$@"