From c462bbafa1ce9b8e55bbe3ea711fccf3bdc6b6c9 Mon Sep 17 00:00:00 2001
From: Philippe Pittoli <karchnu@karchnu.fr>
Date: Wed, 13 Mar 2024 14:40:10 +0100
Subject: [PATCH] Makefile: compile the applications only when a file changed.

---
 bin/should-update | 17 +++++++++++++++++
 makefile          |  7 +++++--
 2 files changed, 22 insertions(+), 2 deletions(-)
 create mode 100755 bin/should-update

diff --git a/bin/should-update b/bin/should-update
new file mode 100755
index 0000000..b49e3a0
--- /dev/null
+++ b/bin/should-update
@@ -0,0 +1,17 @@
+#!/bin/sh
+
+# Should we run the build?
+
+if [ $# -lt 1 ]; then
+	exec >& 2
+	echo "Usage: $0 <exe>"
+	exit 1
+fi
+
+exe=$1
+
+# If the binary hasn't already be compiled.
+[ -f "${exe}" ] || exit 0
+
+v=`find src/ -type f -newer "${exe}" | wc -l`
+test "${v}" != "0"
diff --git a/makefile b/makefile
index 7d30a0e..309728f 100644
--- a/makefile
+++ b/makefile
@@ -1,5 +1,8 @@
 all: build
 
+Q ?= @
+SHOULD_UPDATE = ./bin/should-update
+
 NAME ?= John
 EMAIL ?= john@example.com
 
@@ -61,9 +64,9 @@ permission-set:
 ###################
 
 build-server:
-	shards build authd
+	$(Q)-$(SHOULD_UPDATE) bin/authd && shards build authd
 build-client:
-	shards build authc
+	$(Q)-$(SHOULD_UPDATE) bin/authc && shards build authc
 
 build: build-server build-client