main: client: factor out some common code for "--log-level" option

client.c

@@ -17,6 +17,7 @@
 #include "client-protocol.h"
 #include "debug.h"
 #include "foot-features.h"
+#include "macros.h"
 #include "util.h"
 #include "version.h"
 #include "xmalloc.h"
@@ -156,38 +157,16 @@ main(int argc, char *const *argv)
             break;
 
         case 'd': {
-            static const char *log_level_map[] = {
+            int lvl = log_level_from_string(optarg);
-#if defined(_DEBUG)
+            if (unlikely(lvl < 0)) {
-                [LOG_CLASS_DEBUG] = "debug",
-#endif
-                [LOG_CLASS_INFO] = "info",
-                [LOG_CLASS_WARNING] = "warning",
-                [LOG_CLASS_ERROR] = "error",
-            };
-
-            bool valid_log_level = false;
-            for (size_t i = 0; i < ALEN(log_level_map); i++) {
-                if (strcmp(optarg, log_level_map[i]) == 0) {
-                    log_level = i;
-                    valid_log_level = true;
-                    break;
-                }
-            }
-
-            if (!valid_log_level) {
                 fprintf(
-                    stderr, "-d,--log-level: %s: argument must be one of ",
+                    stderr,
-                    optarg);
+                    "-d,--log-level: %s: argument must be one of %s\n",
-
+                    optarg,
-                for (size_t i = 0; i < ALEN(log_level_map); i++) {
+                    log_level_string_hint());
-                    fprintf(stderr, "'%s'%s",
-                            log_level_map[i],
-                            i < ALEN(log_level_map) - 1 ? " , " : "");
-                }
-                fprintf(stderr, "\n");
-
                 return EXIT_FAILURE;
             }
+            log_level = lvl;
             break;
         }
 

log.c

@@ -10,11 +10,22 @@
 #include <unistd.h>
 
 #include "debug.h"
+#include "util.h"
+#include "xsnprintf.h"
 
 static bool colorize = false;
 static bool do_syslog = true;
 static enum log_class log_level = LOG_CLASS_INFO;
 
+static const char log_level_map[][8] = {
+    [LOG_CLASS_ERROR] = "error",
+    [LOG_CLASS_WARNING] = "warning",
+    [LOG_CLASS_INFO] = "info",
+#if defined(_DEBUG)
+    [LOG_CLASS_DEBUG] = "debug",
+#endif
+};
+
 void
 log_init(enum log_colorize _colorize, bool _do_syslog,
          enum log_facility syslog_facility, enum log_class _log_level)
@@ -149,3 +160,32 @@ void log_errno_provided(enum log_class log_class, const char *module,
     va_end(ap1);
     va_end(ap2);
 }
+
+int
+log_level_from_string(const char *str)
+{
+    if (unlikely(str[0] == '\0'))
+        return -1;
+
+    for (int i = 0, n = ALEN(log_level_map); i < n; i++)
+        if (strcmp(str, log_level_map[i]) == 0)
+            return i;
+
+    return -1;
+}
+
+const char *
+log_level_string_hint(void)
+{
+    static char buf[64];
+    if (buf[0] != '\0')
+        return buf;
+
+    for (size_t i = 0, pos = 0, n = ALEN(log_level_map); i < n; i++) {
+        const char *entry = log_level_map[i];
+        const char *delim = (i + 1 < n) ? ", " : "";
+        pos += xsnprintf(buf + pos, sizeof(buf) - pos, "'%s'%s", entry, delim);
+    }
+
+    return buf;
+}

log.h

@@ -23,6 +23,9 @@ void log_errno_provided(
     const char *file, int lineno, int _errno,
     const char *fmt, ...) PRINTF(6);
 
+int log_level_from_string(const char *str);
+const char *log_level_string_hint(void);
+
 #define LOG_ERR(...)  \
     log_msg(LOG_CLASS_ERROR, LOG_MODULE, __FILE__, __LINE__, __VA_ARGS__)
 #define LOG_ERRNO(...) \

main.c

@@ -23,6 +23,7 @@
 #include "config.h"
 #include "foot-features.h"
 #include "fdm.h"
+#include "macros.h"
 #include "reaper.h"
 #include "render.h"
 #include "server.h"
@@ -310,38 +311,16 @@ main(int argc, char *const *argv)
             break;
 
         case 'd': {
-            static const char *log_level_map[] = {
+            int lvl = log_level_from_string(optarg);
-#if defined(_DEBUG)
+            if (unlikely(lvl < 0)) {
-                [LOG_CLASS_DEBUG] = "debug",
-#endif
-                [LOG_CLASS_INFO] = "info",
-                [LOG_CLASS_WARNING] = "warning",
-                [LOG_CLASS_ERROR] = "error",
-            };
-
-            bool valid_log_level = false;
-            for (size_t i = 0; i < ALEN(log_level_map); i++) {
-                if (strcmp(optarg, log_level_map[i]) == 0) {
-                    log_level = i;
-                    valid_log_level = true;
-                    break;
-                }
-            }
-
-            if (!valid_log_level) {
                 fprintf(
-                    stderr, "-d,--log-level: %s: argument must be one of ",
+                    stderr,
-                    optarg);
+                    "-d,--log-level: %s: argument must be one of %s\n",
-
+                    optarg,
-                for (size_t i = 0; i < ALEN(log_level_map); i++) {
+                    log_level_string_hint());
-                    fprintf(stderr, "'%s'%s",
-                            log_level_map[i],
-                            i < ALEN(log_level_map) - 1 ? " , " : "");
-                }
-                fprintf(stderr, "\n");
-
                 return EXIT_FAILURE;
             }
+            log_level = lvl;
             break;
         }
 

meson.build

@@ -196,7 +196,9 @@ executable(
   'foot-features.h',
   'log.c', 'log.h',
   'macros.h',
+  'util.h',
   'xmalloc.c', 'xmalloc.h',
+  'xsnprintf.c', 'xsnprintf.h',
   version,
   install: true)