ncselector_selected(), unit tests

include/notcurses.h

@@ -2138,6 +2138,9 @@ API struct ncselector* ncselector_aligned(struct ncplane* n, int y, ncalign_e al
 API int ncselector_additem(struct ncselector* n, const struct selector_item* item);
 API int ncselector_delitem(struct ncselector* n, const char* item);
 
+// Return a copy of the currently-selected option. NULL if there are no items.
+API char* ncselector_selected(const struct ncselector* n);
+
 // Move up or down in the list. If 'newitem' is not NULL, the newly-selected
 // option will be strdup()ed and assigned to '*newitem' (and must be free()d by
 // the caller).

src/lib/selector.c

@@ -185,12 +185,19 @@ int ncselector_delitem(ncselector* n, const char* item){
   return -1; // wasn't found
 }
 
+char* ncselector_selected(const ncselector* n){
+  if(n->itemcount == 0){
+    return NULL;
+  }
+  return strdup(n->items[n->selected].option);
+}
+
 void ncselector_previtem(ncselector* n, char** newitem){
   if(n->selected == 0){
     n->selected = n->itemcount;
   }
   --n->selected;
-  if(newitem){
+  if(newitem && n->itemcount){
     *newitem = strdup(n->items[n->selected].option);
   }
   ncselector_draw(n);
@@ -201,7 +208,7 @@ void ncselector_nextitem(ncselector* n, char** newitem){
   if(n->selected == n->itemcount){
     n->selected = 0;
   }
-  if(newitem){
+  if(newitem && n->itemcount){
     *newitem = strdup(n->items[n->selected].option);
   }
   ncselector_draw(n);

tests/selector.cpp

@@ -22,6 +22,7 @@ TEST_CASE("SelectorTest") {
     struct ncselector* ncs = ncselector_create(notcurses_stdplane(nc_), 0, 0, &opts);
     REQUIRE(nullptr != ncs);
     CHECK(0 == notcurses_render(nc_));
+    CHECK(nullptr == ncselector_selected(ncs));
     ncselector_destroy(ncs, nullptr);
   }
 
@@ -67,6 +68,59 @@ TEST_CASE("SelectorTest") {
     ncselector_destroy(ncs, nullptr);
   }
 
+  SUBCASE("EmptySelectorMovement") {
+    struct selector_options opts{};
+    struct ncselector* ncs = ncselector_create(notcurses_stdplane(nc_), 0, 0, &opts);
+    REQUIRE(nullptr != ncs);
+    CHECK(0 == notcurses_render(nc_));
+    auto sel = ncselector_selected(ncs);
+    REQUIRE(nullptr == sel);
+    ncselector_nextitem(ncs, &sel);
+    REQUIRE(nullptr == sel);
+    CHECK(0 == notcurses_render(nc_));
+    ncselector_previtem(ncs, &sel);
+    REQUIRE(nullptr == sel);
+    CHECK(0 == notcurses_render(nc_));
+    ncselector_destroy(ncs, nullptr);
+  }
+
+  SUBCASE("SelectorMovement") {
+    selector_item items[] = {
+      { strdup("op1"), strdup("this is option 1"), },
+      { strdup("2ndop"), strdup("this is option #2"), },
+      { strdup("tres"), strdup("option the third"), },
+    };
+    struct selector_options opts{};
+    opts.items = items;
+    opts.itemcount = sizeof(items) / sizeof(*items);
+    struct ncselector* ncs = ncselector_create(notcurses_stdplane(nc_), 0, 0, &opts);
+    REQUIRE(nullptr != ncs);
+    CHECK(0 == notcurses_render(nc_));
+    auto sel = ncselector_selected(ncs);
+    REQUIRE(nullptr != sel);
+    CHECK(0 == strcmp(sel, items[0].option));
+    free(sel);
+    ncselector_nextitem(ncs, &sel);
+    REQUIRE(nullptr != sel);
+    CHECK(0 == strcmp(sel, items[1].option));
+    free(sel);
+    ncselector_previtem(ncs, &sel);
+    REQUIRE(nullptr != sel);
+    CHECK(0 == strcmp(sel, items[0].option));
+    free(sel);
+    // wrap around from the top to bottom...
+    ncselector_previtem(ncs, &sel);
+    REQUIRE(nullptr != sel);
+    CHECK(0 == strcmp(sel, items[2].option));
+    free(sel);
+    // ...and back to the top
+    ncselector_nextitem(ncs, &sel);
+    REQUIRE(nullptr != sel);
+    CHECK(0 == strcmp(sel, items[0].option));
+    free(sel);
+    ncselector_destroy(ncs, nullptr);
+  }
+
   CHECK(0 == notcurses_stop(nc_));
   CHECK(0 == fclose(outfp_));
 }