strmap: set errno to ENOENT even if we return NULL.

It seems redundant: strmap_get() and strmap_del() can only return NULL
when the string is not a member.  However, it became clear in writing
ccan/tsort that it's much more convenient for callers if we set errno
in this case too, so they can pass it up.

diff --git a/ccan/strmap/strmap.c b/ccan/strmap/strmap.c
index 2b89fe0da66cdf8185b4096681175601a2a01fb0..872ca544c6aab1fa3b9d813534b74486cf77ec70 100644 (file)
--- a/ccan/strmap/strmap.c
+++ b/ccan/strmap/strmap.c
@@ -39,12 +39,13 @@ void *strmap_get_(const struct strmap *map, const char *member)
 {
        struct strmap *n;
 
-       /* Empty map? */
-       if (!map->u.n)
-               return NULL;
-       n = closest((struct strmap *)map, member);
-       if (streq(member, n->u.s))
-               return n->v;
+       /* Not empty map? */
+       if (map->u.n) {
+               n = closest((struct strmap *)map, member);
+               if (streq(member, n->u.s))
+                       return n->v;
+       }
+       errno = ENOENT;
        return NULL;
 }
 
@@ -129,8 +130,10 @@ char *strmap_del_(struct strmap *map, const char *member, void **valuep)
        u8 direction = 0; /* prevent bogus gcc warning. */
 
        /* Empty map? */
-       if (!map->u.n)
+       if (!map->u.n) {
+               errno = ENOENT;
                return NULL;
+       }
 
        /* Find closest, but keep track of parent. */
        n = map;
@@ -148,8 +151,10 @@ char *strmap_del_(struct strmap *map, const char *member, void **valuep)
        }
 
        /* Did we find it? */
-       if (!streq(member, n->u.s))
+       if (!streq(member, n->u.s)) {
+               errno = ENOENT;
                return NULL;
+       }
 
        ret = n->u.s;
        if (valuep)

diff --git a/ccan/strmap/strmap.h b/ccan/strmap/strmap.h
index e85b8c8f898f599d9d292f8367d1dcf3d7468fdd..d6104942f4cea6c7cb218bfd386ced9f96ec3b1a 100644 (file)
--- a/ccan/strmap/strmap.h
+++ b/ccan/strmap/strmap.h
@@ -77,7 +77,7 @@ static inline bool strmap_empty_(const struct strmap *map)
  * @map: the typed strmap to search.
  * @member: the string to search for.
  *
- * Returns the value, or NULL if it isn't in the map.
+ * Returns the value, or NULL if it isn't in the map (and sets errno = ENOENT).
  *
  * Example:
  *     int *val = strmap_get(&map, "hello");
@@ -118,7 +118,9 @@ bool strmap_add_(struct strmap *map, const char *member, const void *value);
  * @member: the string to remove from the map.
  * @valuep: the value (if non-NULL)
  *
- * This returns the string which was passed to strmap_map(), or NULL.
+ * This returns the string which was passed to strmap_map(), or NULL if
+ * it was not in the map (and sets errno = ENOENT).
+ *
  * This means that if you allocated a string (eg. using strdup()), you
  * can free it here.  Similarly, the value is returned in @valuep if
  * @valuep is not NULL.

diff --git a/ccan/strmap/test/run.c b/ccan/strmap/test/run.c
index 34302846f120f873aa856e2c08f750c48af5745d..aaa8618125c14d228a0a08da695aff8bd4c7e708 100644 (file)
--- a/ccan/strmap/test/run.c
+++ b/ccan/strmap/test/run.c
@@ -14,20 +14,25 @@ int main(void)
        char *v;
 
        /* This is how many tests you plan to run */
-       plan_tests(32);
+       plan_tests(42);
 
        strmap_init(&map);
 
        ok1(!strmap_get(&map, str));
+       ok1(errno == ENOENT);
        ok1(!strmap_get(&map, none));
+       ok1(errno == ENOENT);
        ok1(!strmap_del(&map, str, NULL));
+       ok1(errno == ENOENT);
        ok1(!strmap_del(&map, none, NULL));
+       ok1(errno == ENOENT);
 
        ok1(strmap_add(&map, str, val));
        ok1(strmap_get(&map, str) == val);
        /* We compare the string, not the pointer. */
        ok1(strmap_get(&map, dup) == val);
        ok1(!strmap_get(&map, none));
+       ok1(errno == ENOENT);
 
        /* Add a duplicate should fail. */
        ok1(!strmap_add(&map, dup, val));
@@ -38,18 +43,23 @@ int main(void)
        ok1(strmap_del(&map, dup, &v) == str);
        ok1(v == val);
        ok1(!strmap_get(&map, str));
+       ok1(errno == ENOENT);
        ok1(!strmap_get(&map, none));
+       ok1(errno == ENOENT);
 
        /* Try insert and delete of empty string. */
        ok1(strmap_add(&map, none, none));
        ok1(strmap_get(&map, none) == none);
        ok1(!strmap_get(&map, str));
+       ok1(errno == ENOENT);
 
        /* Delete should return original string. */
        ok1(strmap_del(&map, "", &v) == none);
        ok1(v == none);
        ok1(!strmap_get(&map, str));
+       ok1(errno == ENOENT);
        ok1(!strmap_get(&map, none));
+       ok1(errno == ENOENT);
 
        /* Both at once... */
        ok1(strmap_add(&map, none, none));