strmap: allow const arguments to strset_iterate().

ccan/strmap/strmap.c

@@ -174,17 +174,19 @@ char *strmap_del_(struct strmap *map, const char *member, void **valuep)
 }
 
 static bool iterate(struct strmap n,
-		    bool (*handle)(const char *, void *, void *), void *data)
+		    bool (*handle)(const char *, void *, void *),
+		    const void *data)
 {
 	if (n.v)
-		return handle(n.u.s, n.v, data);
+		return handle(n.u.s, n.v, (void *)data);
 
 	return iterate(n.u.n->child[0], handle, data)
 		|| iterate(n.u.n->child[1], handle, data);
 }
 
 void strmap_iterate_(const struct strmap *map,
-		     bool (*handle)(const char *, void *, void *), void *data)
+		     bool (*handle)(const char *, void *, void *),
+		     const void *data)
 {
 	/* Empty map? */
 	if (!map->u.n)

ccan/strmap/strmap.h

@@ -189,8 +189,8 @@ void strmap_clear_(struct strmap *map);
 						  __typeof__(arg)), (handle)), \
 			(arg))
 void strmap_iterate_(const struct strmap *map,
-		     bool (*handle)(const char *, void *, void *), void *data);
-
+		     bool (*handle)(const char *, void *, void *),
+		     const void *data);
 
 /**
  * strmap_prefix - return a submap matching a prefix

ccan/strmap/test/run-iterate-const.c

@@ -0,0 +1,32 @@
+#include <ccan/strmap/strmap.h>
+#include <ccan/strmap/strmap.c>
+#include <ccan/tap/tap.h>
+
+static bool found = false;
+
+/* Make sure const args work. */
+static bool find_string(const char *str, char *member, const char *cmp)
+{
+	if (strcmp(member, cmp) == 0)
+		found = true;
+	return false;
+}
+
+int main(void)
+{
+	struct strmap_charp {
+		STRMAP_MEMBERS(char *);
+	} map;
+
+	plan_tests(3);
+
+	strmap_init(&map);
+	ok1(strmap_add(&map, "hello", "hello"));
+	ok1(strmap_add(&map, "world", "world"));
+	strmap_iterate(&map, find_string, (const char *)"hello");
+	ok1(found);
+	strmap_clear(&map);
+
+	/* This exits depending on whether all tests passed */
+	return exit_status();
+}