cocci: use strempty() at more places

This shortens the code by a few lines.

coccinelle/strempty.cocci

@@ -8,3 +8,41 @@ expression s;
 @@
 - s ? s : ""
 + strempty(s)
+@@
+expression s;
+@@
+- if (!s)
+-         s = "";
++ s = strempty(s);
+@@
+expression s;
+@@
+- s ?: "(null)"
++ strnull(s)
+@@
+expression s;
+@@
+- s ? s : "(null)"
++ strnull(s)
+@@
+expression s;
+@@
+- if (!s)
+-         s = "(null)";
++ s = strnull(s);
+@@
+expression s;
+@@
+- s ?: "n/a"
++ strna(s)
+@@
+expression s;
+@@
+- s ? s : "n/a"
++ strna(s)
+@@
+expression s;
+@@
+- if (!s)
+-         s = "n/a";
++ s = strna(s);

src/basic/fileio.c

@@ -1225,8 +1225,7 @@ int tempfn_xxxxxx(const char *p, const char *extra, char **ret) {
         if (!filename_is_valid(fn))
                 return -EINVAL;
 
-        if (!extra)
+        extra = strempty(extra);
-                extra = "";
 
         t = new(char, strlen(p) + 2 + strlen(extra) + 6 + 1);
         if (!t)
@@ -1259,8 +1258,7 @@ int tempfn_random(const char *p, const char *extra, char **ret) {
         if (!filename_is_valid(fn))
                 return -EINVAL;
 
-        if (!extra)
+        extra = strempty(extra);
-                extra = "";
 
         t = new(char, strlen(p) + 2 + strlen(extra) + 16 + 1);
         if (!t)
@@ -1300,8 +1298,7 @@ int tempfn_random_child(const char *p, const char *extra, char **ret) {
                         return r;
         }
 
-        if (!extra)
+        extra = strempty(extra);
-                extra = "";
 
         t = new(char, strlen(p) + 3 + strlen(extra) + 16 + 1);
         if (!t)

src/basic/string-util.h

@@ -52,15 +52,15 @@ static inline bool streq_ptr(const char *a, const char *b) {
 }
 
 static inline const char* strempty(const char *s) {
-        return s ? s : "";
+        return s ?: "";
 }
 
 static inline const char* strnull(const char *s) {
-        return s ? s : "(null)";
+        return s ?: "(null)";
 }
 
 static inline const char *strna(const char *s) {
-        return s ? s : "n/a";
+        return s ?: "n/a";
 }
 
 static inline bool isempty(const char *p) {

src/core/job.c

@@ -306,8 +306,7 @@ void job_dump(Job *j, FILE*f, const char *prefix) {
         assert(j);
         assert(f);
 
-        if (!prefix)
+        prefix = strempty(prefix);
-                prefix = "";
 
         fprintf(f,
                 "%s-> Job %u:\n"

src/core/kill.c

@@ -34,8 +34,7 @@ void kill_context_init(KillContext *c) {
 void kill_context_dump(KillContext *c, FILE *f, const char *prefix) {
         assert(c);
 
-        if (!prefix)
+        prefix = strempty(prefix);
-                prefix = "";
 
         fprintf(f,
                 "%sKillMode: %s\n"

src/journal/journal-send.c

@@ -418,8 +418,7 @@ _public_ int sd_journal_stream_fd(const char *identifier, int priority, int leve
 
         fd_inc_sndbuf(fd, SNDBUF_SIZE);
 
-        if (!identifier)
+        identifier = strempty(identifier);
-                identifier = "";
 
         l = strlen(identifier);
         header = alloca(l + 1 + 1 + 2 + 2 + 2 + 2 + 2);

src/shared/condition.c

@@ -653,8 +653,7 @@ void condition_dump(Condition *c, FILE *f, const char *prefix, const char *(*to_
         assert(c);
         assert(f);
 
-        if (!prefix)
+        prefix = strempty(prefix);
-                prefix = "";
 
         fprintf(f,
                 "%s\t%s: %s%s%s %s\n",

src/udev/udev-builtin-input_id.c

@@ -102,8 +102,7 @@ static void get_cap_mask(struct udev_device *dev,
         unsigned long val;
 
         v = udev_device_get_sysattr_value(pdev, attr);
-        if (!v)
+        v = strempty(v);
-                v = "";
 
         xsprintf(text, "%s", v);
         log_debug("%s raw kernel attribute: %s", attr, text);