From 9a5cedc319d56bbf3e65046e8e73ee94612f0fef Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>
Date: Fri, 16 Nov 2018 10:39:57 +0100
Subject: [PATCH] ac-power: define main through macro

I decided to use a separate definition for this because it's too easy to return
positive from functions which don't need this distinction and only return
negative on error and success otherwise.
---
 src/ac-power/ac-power.c | 15 +++++++--------
 src/basic/macro.h       | 10 ++++++++++
 2 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/src/ac-power/ac-power.c b/src/ac-power/ac-power.c
index 7ca72ef5f59..2d8cbb985fe 100644
--- a/src/ac-power/ac-power.c
+++ b/src/ac-power/ac-power.c
@@ -63,7 +63,7 @@ static int parse_argv(int argc, char *argv[]) {
         return 1;
 }
 
-int main(int argc, char *argv[]) {
+static int run(int argc, char *argv[]) {
         int r;
 
         /* This is mostly intended to be used for scripts which want
@@ -74,17 +74,16 @@ int main(int argc, char *argv[]) {
 
         r = parse_argv(argc, argv);
         if (r <= 0)
-                goto finish;
+                return r;
 
         r = on_ac_power();
-        if (r < 0) {
-                log_error_errno(r, "Failed to read AC status: %m");
-                goto finish;
-        }
+        if (r < 0)
+                return log_error_errno(r, "Failed to read AC status: %m");
 
         if (arg_verbose)
                 puts(yes_no(r));
 
-finish:
-        return r < 0 ? EXIT_FAILURE : !r;
+        return r == 0;
 }
+
+DEFINE_MAIN_FUNCTION_WITH_POSITIVE_FAILURE(run);
diff --git a/src/basic/macro.h b/src/basic/macro.h
index cf41a5ee8a1..dedcba22e7e 100644
--- a/src/basic/macro.h
+++ b/src/basic/macro.h
@@ -515,4 +515,14 @@ static inline int __coverity_check__(int condition) {
                 return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;             \
         }
 
+/* Zero is mapped to EXIT_SUCCESS, and both negative and positive values
+ * are mapped to EXIT_FAILURE.
+ * Note: this means "true" maps to EXIT_FAILURE. */
+#define DEFINE_MAIN_FUNCTION_WITH_POSITIVE_FAILURE(impl)                \
+        int main(int argc, char *argv[]) {                              \
+                int r;                                                  \
+                r = impl(argc, argv);                                   \
+                return r != 0 ? EXIT_FAILURE : EXIT_SUCCESS;            \
+        }
+
 #include "log.h"