bin: add check-gx-program

License: MIT
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>

bin/check_gx_program

+#!/bin/sh
+#
+# Check if a gx program is installed and if its version is at least
+# equal to a minimum version number.
+#
+# Call it for example like this:
+#
+#   $ check_gx_program "gx-go" "0.2.0" "Use 'make gx_upgrade' to install or upgrade gx-go."
+#
+# or:
+#
+#   $ check_gx_program "gx" "0.3" "Use 'make gx_upgrade' to install or upgrade gx."
+#
+
+USAGE="$0 GX_PROGRAM_NAME GX_MIN_VERSION UPGRADE_MSG"
+
+die() {
+    printf >&2 "fatal: %s\n" "$@"
+    exit 1
+}
+
+# Get arguments
+
+test "$#" -eq "3" || die "This program must be passed exactly 3 arguments" "Usage: $USAGE"
+
+GX_PROGRAM_NAME="$1"
+GX_MIN_VERSION="$2"
+UPGRADE_MSG="$3"
+
+die_upgrade() {
+    printf >&2 "fatal: %s\n" "$@"
+    printf >&2 "=> %s\n" "$UPGRADE_MSG"
+    exit 1
+}
+
+major_number() {
+    vers="$1"
+
+    # Hack around 'expr' exiting with code 1 when it outputs 0
+    case "$vers" in
+	0) echo "0" ;;
+	0.*) echo "0" ;;
+	*) expr "$vers" : "\([^.]*\).*" || return 1
+    esac
+}
+
+check_at_least_version() {
+    MIN_VERS="$1"
+    CUR_VERS="$2"
+    PROG_NAME="$3"
+
+    # Get major, minor and fix numbers for each version
+    MIN_MAJ=$(major_number "$MIN_VERS") || die "No major version number in '$MIN_VERS' for '$PROG_NAME'"
+    CUR_MAJ=$(major_number "$CUR_VERS") || die "No major version number in '$CUR_VERS' for '$PROG_NAME'"
+    if MIN_MIN=$(expr "$MIN_VERS" : "[^.]*\.\([^.]*\).*")
+    then
+	MIN_FIX=$(expr "$MIN_VERS" : "[^.]*\.[^.]*\.\([^.]*\).*") || MIN_FIX="0"
+    else
+	MIN_MIN="0"
+	MIN_FIX="0"
+    fi
+    if CUR_MIN=$(expr "$CUR_VERS" : "[^.]*\.\([^.]*\).*")
+    then
+	CUR_FIX=$(expr "$CUR_VERS" : "[^.]*\.[^.]*\.\([^.]*\).*") || CUR_FIX="0"
+    else
+	CUR_MIN="0"
+	CUR_FIX="0"
+    fi
+
+    # Compare versions
+    VERS_LEAST="$PROG_NAME version '$CUR_VERS' should be at least '$MIN_VERS'"
+    test "$CUR_MAJ" -gt $(expr "$MIN_MAJ" - 1) || die_upgrade "$VERS_LEAST"
+    test "$CUR_MAJ" -gt "$MIN_MAJ" || {
+	test "$CUR_MIN" -gt $(expr "$MIN_MIN" - 1) || die_upgrade "$VERS_LEAST"
+	test "$CUR_MIN" -gt "$MIN_MIN" || {
+	    test "$CUR_FIX" -ge "$MIN_FIX" || die_upgrade "$VERS_LEAST"
+	}
+    }
+}
+
+# Check that the gx program exists
+
+type "$GX_PROGRAM_NAME" >/dev/null || die_upgrade "Program $GX_PROGRAM_NAME is not installed!"
+
+# Check the gx program version
+
+VERS_STR=$($GX_PROGRAM_NAME -v 2>&1) || die "'$GX_PROGRAM_NAME -v' failed with output: $VERS_STR"
+
+GX_CUR_VERSION=$(expr "$VERS_STR" : "$GX_PROGRAM_NAME version \(.*\)") || die "Invalid '$GX_PROGRAM_NAME -v' output: $VERS_STR"
+
+check_at_least_version "$GX_MIN_VERSION" "$GX_CUR_VERSION" "$GX_PROGRAM_NAME"