trade a bin if any contents can be traded

the new trade screens will make it easy to filter out unwanted items
later

docs/dev/Lua API.rst

@@ -1797,7 +1797,12 @@ Items module
 
 * ``dfhack.items.canTradeWithContents(item)``
 
-  Checks whether the item and all items it contains, if any, can be traded.
+  Returns false if the item or any contained items cannot be traded.
+
+* ``canTradeAnyWithContents(item)``
+
+  Returns true if the item is empty and can be traded or if the item contains
+  any item that can be traded.
 
 * ``dfhack.items.markForTrade(item, depot)``
 

library/LuaApi.cpp

@@ -2025,6 +2025,7 @@ static const LuaWrapper::FunctionReg dfhack_items_module[] = {
     WRAPM(Items, checkMandates),
     WRAPM(Items, canTrade),
     WRAPM(Items, canTradeWithContents),
+    WRAPM(Items, canTradeAnyWithContents),
     WRAPM(Items, markForTrade),
     WRAPM(Items, isRouteVehicle),
     WRAPM(Items, isSquadEquipment),

library/include/modules/Items.h

@@ -199,8 +199,10 @@ DFHACK_EXPORT int32_t createItem(df::item_type type, int16_t item_subtype, int16
 DFHACK_EXPORT bool checkMandates(df::item *item);
 /// Checks whether the item can be traded
 DFHACK_EXPORT bool canTrade(df::item *item);
-/// Checks whether the item and all items it contains, if any, can be traded
+/// Returns false if the item or any contained items cannot be traded
 DFHACK_EXPORT bool canTradeWithContents(df::item *item);
+/// Returns true if the item is empty and can be traded or if the item contains any item that can be traded
+DFHACK_EXPORT bool canTradeAnyWithContents(df::item *item);
 /// marks the given item for trade at the given depot
 DFHACK_EXPORT bool markForTrade(df::item *item, df::building_tradedepotst *depot);
 /// Returns true if an active caravan will pay extra for the given item

library/modules/Items.cpp

@@ -2172,6 +2172,27 @@ bool Items::canTradeWithContents(df::item *item)
     return true;
 }
 
+bool Items::canTradeAnyWithContents(df::item *item)
+{
+    CHECK_NULL_POINTER(item);
+
+    if (item->flags.bits.in_inventory)
+        return false;
+
+    vector<df::item*> contained_items;
+    getContainedItems(item, &contained_items);
+
+    if (contained_items.empty())
+        return canTrade(item);
+
+    for (df::item *cit : contained_items) {
+        if (canTrade(cit))
+            return true;
+    }
+
+    return false;
+}
+
 bool Items::markForTrade(df::item *item, df::building_tradedepotst *depot) {
     CHECK_NULL_POINTER(item);
     CHECK_NULL_POINTER(depot);

plugins/logistics.cpp

@@ -317,7 +317,7 @@ public:
     }
 
     bool can_designate(color_ostream& out, df::item* item) override {
-        return Items::canTradeWithContents(item);
+        return Items::canTradeAnyWithContents(item);
     }
 
     bool designate(color_ostream& out, df::item* item) override {