Improve kittens thread safety and shutdown with core

The bools could use acquire&release memory order or even relaxed but I
didn't think code was worth auditing for such low level optimizations.
Sequantial consistent is fast enough but much harder to use incorrectly.

The timeLast is protected by CoreSuspender lock. plugin_update is only
called when CoreSuspender lock is held.

The last_menu is protected by trackmenu_flg loads and stores.

library/include/Console.h

@@ -26,6 +26,7 @@ distribution.
 #include "Pragma.h"
 #include "Export.h"
 #include "ColorText.h"
+#include <atomic>
 #include <deque>
 #include <fstream>
 #include <assert.h>
@@ -163,6 +164,6 @@ namespace  DFHack
     private:
         Private * d;
         tthread::recursive_mutex * wlock;
-        bool inited;
+        std::atomic<bool> inited;
     };
 }

plugins/devel/kittens.cpp

@@ -1,3 +1,4 @@
+#include <atomic>
 #include <vector>
 #include <string>
 
@@ -24,13 +25,12 @@ DFHACK_PLUGIN_IS_ENABLED(is_enabled);
 REQUIRE_GLOBAL(ui);
 REQUIRE_GLOBAL(world);
 
-//FIXME: possible race conditions with calling kittens from the IO thread and shutdown from Core.
+std::atomic<bool> shutdown_flag{false};
-volatile bool shutdown_flag = false;
+std::atomic<bool> final_flag{true};
-volatile bool final_flag = true;
+std::atomic<bool> timering{false};
-bool timering = false;
+std::atomic<bool> trackmenu_flg{false};
-bool trackmenu_flg = false;
+std::atomic<uint8_t> trackpos_flg{0};
-bool trackpos_flg = false;
+std::atomic<uint8_t> statetrack{0};
-bool statetrack = false;
 int32_t last_designation[3] = {-30000, -30000, -30000};
 int32_t last_mouse[2] = {-1, -1};
 df::ui_sidebar_mode last_menu = df::ui_sidebar_mode::Default;
@@ -93,12 +93,10 @@ DFhackCExport command_result plugin_onstatechange(color_ostream &out, state_chan
 
 DFhackCExport command_result plugin_onupdate ( color_ostream &out )
 {
-    if(timering == true)
+    if(timering)
     {
         uint64_t time2 = GetTimeMs64();
-        // harmless potential data race here...
         uint64_t delta = time2-timeLast;
-        // harmless potential data race here...
         timeLast = time2;
         out.print("Time delta = %d ms\n", int(delta));
     }
@@ -135,30 +133,30 @@ DFhackCExport command_result plugin_onupdate ( color_ostream &out )
 
 command_result trackmenu (color_ostream &out, vector <string> & parameters)
 {
-    if(trackmenu_flg)
+    bool is_running = trackmenu_flg.exchange(false);
+    if(is_running)
     {
-        trackmenu_flg = false;
         return CR_OK;
     }
     else
     {
-        trackmenu_flg = true;
         is_enabled = true;
         last_menu = ui->main.mode;
         out.print("Menu: %d\n",last_menu);
+        trackmenu_flg = true;
         return CR_OK;
     }
 }
 command_result trackpos (color_ostream &out, vector <string> & parameters)
 {
-    trackpos_flg = !trackpos_flg;
+    trackpos_flg.fetch_xor(1);
     is_enabled = true;
     return CR_OK;
 }
 
 command_result trackstate ( color_ostream& out, vector< string >& parameters )
 {
-    statetrack = !statetrack;
+    statetrack.fetch_xor(1);
     return CR_OK;
 }
 
@@ -180,20 +178,19 @@ command_result colormods (color_ostream &out, vector <string> & parameters)
 
 command_result ktimer (color_ostream &out, vector <string> & parameters)
 {
-    if(timering)
+    bool is_running = timering.exchange(false);
+    if(is_running)
     {
-        timering = false;
         return CR_OK;
     }
     uint64_t timestart = GetTimeMs64();
     {
         CoreSuspender suspend;
+        uint64_t timeend = GetTimeMs64();
+        timeLast = timeend;
+        timering = true;
+        out.print("Time to suspend = %d ms\n", int(timeend - timestart));
     }
-    uint64_t timeend = GetTimeMs64();
-    out.print("Time to suspend = %d ms\n", int(timeend - timestart));
-    // harmless potential data race here...
-    timeLast = timeend;
-    timering = true;
     is_enabled = true;
     return CR_OK;
 }
@@ -255,7 +252,7 @@ command_result kittens (color_ostream &out, vector <string> & parameters)
     Console::color_value color = COLOR_BLUE;
     while(1)
     {
-        if(shutdown_flag)
+        if(shutdown_flag || !con.isInited())
         {
             final_flag = true;
             con.reset_color();