Add safer helpers to get STRING_X keys from interface_key sets

A few plugins were using input->rbegin() previously, which crashes
if input is empty and isn't strictly guaranteed to return a
STRING_X key.

NEWS

@@ -34,6 +34,7 @@ DFHack Future
         gui/hack-wish now properly assigns quality to items.
         gui/gm-editor handles lua tables properly
         search: fixed crash in unit list after cancelling a job
+        stocks: fixed a crash when right-clicking
         steam-engine:
           - fixed a crash on arena load
           - number keys (e.g. 2/8) take priority over cursor keys when applicable

plugins/buildingplan.cpp

@@ -189,7 +189,7 @@ struct buildingplan_hook : public df::viewscreen_dwarfmodest
         else if (isInNobleRoomQueryMode())
         {
             auto np = getNoblePositionOfSelectedBuildingOwner();
-            df::interface_key last_token = *input->rbegin();
+            df::interface_key last_token = get_string_key(input);
             if (last_token >= interface_key::STRING_A048 && last_token <= interface_key::STRING_A058)
             {
                 int selection = last_token - interface_key::STRING_A048;

plugins/search.cpp

@@ -5,6 +5,8 @@
 
 #include <VTableInterpose.h>
 
+#include "uicommon.h"
+
 #include "df/ui_look_list.h"
 #include "df/viewscreen_announcelistst.h"
 #include "df/viewscreen_petst.h"
@@ -65,12 +67,6 @@ to use.
 */
 
 
-void OutputString(int8_t color, int &x, int y, const std::string &text)
-{
-    Screen::paintString(Screen::Pen(' ', color, 0), x, y, text);
-    x += text.length();
-}
-
 void make_text_dim(int x1, int x2, int y)
 {
     for (int x = x1; x <= x2; x++)
@@ -225,11 +221,7 @@ public:
         {
             // Query typing mode
 
-            if (input->empty())
-            {
-                return false;
-            }
-            df::interface_key last_token = *input->rbegin();
+            df::interface_key last_token = get_string_key(input);
             int charcode = Screen::keyToChar(last_token);
             if (charcode >= 32 && charcode <= 126)
             {

plugins/uicommon.h

@@ -206,6 +206,20 @@ static string pad_string(string text, const int size, const bool front = true, c
     }
 }
 
+static df::interface_key get_string_key(const std::set<df::interface_key> *input)
+{
+    for (auto it = input->begin(); it != input->end(); ++it)
+    {
+        if (DFHack::Screen::keyToChar(*it) >= 0)
+            return *it;
+    }
+    return df::interface_key::NONE;
+}
+
+static char get_string_input(const std::set<df::interface_key> *input)
+{
+    return DFHack::Screen::keyToChar(get_string_key(input));
+}
 
 /*
  * Utility Functions
@@ -370,7 +384,7 @@ protected:
         y2 = sp->room.y + sp->room.height;
     }
 
-private:
+protected:
     int x1, x2, y1, y2, z;
 };
 
@@ -414,7 +428,7 @@ public:
         DFHack::World::DeletePersistentData(config);
     }
 
-private:
+protected:
     PersistentDataItem config;
     string persistence_key;
 };
@@ -799,7 +813,7 @@ public:
         else if (allow_search)
         {
             // Search query typing mode always on
-            df::interface_key last_token = *input->rbegin();
+            df::interface_key last_token = get_string_key(input);
             int charcode = Screen::keyToChar(last_token);
             if ((charcode >= 96 && charcode <= 123) || charcode == 32)
             {
@@ -873,7 +887,7 @@ public:
         return display_list.size();
     }
 
-private:
+protected:
     static void clear_fn(ListEntry<T> &e) { e.selected = false; }
     static bool sort_fn(ListEntry<T> const& a, ListEntry<T> const& b) { return a.text.compare(b.text) < 0; }
 

plugins/zone.cpp

@@ -41,6 +41,7 @@ using namespace std;
 #include "Export.h"
 #include "PluginManager.h"
 #include "MiscUtils.h"
+#include "uicommon.h"
 
 #include "LuaTools.h"
 #include "DataFuncs.h"
@@ -3705,12 +3706,6 @@ DFHACK_PLUGIN_LUA_COMMANDS {
 
 //START zone filters
 
-void OutputString(int8_t color, int &x, int y, const std::string &text)
-{
-    Screen::paintString(Screen::Pen(' ', color, 0), x, y, text);
-    x += text.length();
-}
-
 class zone_filter
 {
 public:
@@ -3856,7 +3851,7 @@ public:
                 return false;
             }
 
-            df::interface_key last_token = *input->rbegin();
+            df::interface_key last_token = get_string_key(input);
             int charcode = Screen::keyToChar(last_token);
             if (charcode >= 32 && charcode <= 126)
             {