3 files changed, 59 insertions, 14 deletions

diff --git a/src/main/java/gregtech/api/gui/GT_GUIColorOverride.java b/src/main/java/gregtech/api/gui/GT_GUIColorOverride.java
index f934102eb9..2d6268dbec 100644
--- a/src/main/java/gregtech/api/gui/GT_GUIColorOverride.java
+++ b/src/main/java/gregtech/api/gui/GT_GUIColorOverride.java
@@ -1,28 +1,69 @@
 package gregtech.api.gui;
 
+import com.google.common.cache.CacheBuilder;
+import com.google.common.cache.CacheLoader;
+import com.google.common.cache.LoadingCache;
+import com.google.common.util.concurrent.UncheckedExecutionException;
+import cpw.mods.fml.relauncher.FMLLaunchHandler;
+import cpw.mods.fml.relauncher.Side;
 import gregtech.api.GregTech_API;
 import gregtech.api.util.ColorsMetadataSection;
-import java.io.IOException;
+import java.util.concurrent.ExecutionException;
+import javax.annotation.Nonnull;
 import net.minecraft.client.Minecraft;
 import net.minecraft.client.resources.IResource;
 import net.minecraft.util.ResourceLocation;
 
 public class GT_GUIColorOverride {
-
+    private static final Object NOT_FOUND = new Object();
+    private static final LoadingCache<ResourceLocation, Object> cache = CacheBuilder.newBuilder()
+            .softValues()
+            .build(new CacheLoader<ResourceLocation, Object>() {
+                @Override
+                public Object load(@Nonnull ResourceLocation key) throws Exception {
+                    IResource ir = Minecraft.getMinecraft().getResourceManager().getResource(key);
+                    if (ir.hasMetadata()) return ir.getMetadata("colors");
+                    // return a dummy object because LoadingCache doesn't like null
+                    return NOT_FOUND;
+                }
+            });
+    private static final GT_GUIColorOverride FALLBACK = new GT_GUIColorOverride();
     private ColorsMetadataSection cmSection;
 
+    public static GT_GUIColorOverride get(String fullLocation) {
+        // see other get for more info
+        if (FMLLaunchHandler.side() != Side.CLIENT) return FALLBACK;
+        return new GT_GUIColorOverride(new ResourceLocation(fullLocation));
+    }
+
+    public static GT_GUIColorOverride get(ResourceLocation path) {
+        // use dummy fallback if there isn't such thing as a resource pack.
+        // #side() usually has two possible return value, but since this might be called by test code, it might
+        // also return null when in test env. Using #isClient will cause a NPE. A plain inequality test won't.
+        // FMLCommonHandler's #getSide() might trigger a NPE when in test env, so no.
+        if (FMLLaunchHandler.side() != Side.CLIENT) return FALLBACK;
+        return new GT_GUIColorOverride(path);
+    }
+
+    private GT_GUIColorOverride() {
+        cmSection = null;
+    }
+
+    /**
+     * @deprecated use {@link #get(String)} instead.
+     */
+    @Deprecated
     public GT_GUIColorOverride(String guiTexturePath) {
+        this(new ResourceLocation(guiTexturePath));
+    }
+
+    private GT_GUIColorOverride(ResourceLocation resourceLocation) {
         try {
-            // this is dumb, but CombTypeTest causes cascading class load
-            // and leads to instantiation of GT_CoverBehaviorBase
-            if (Minecraft.getMinecraft() == null) return;
-            IResource ir =
-                    Minecraft.getMinecraft().getResourceManager().getResource(new ResourceLocation(guiTexturePath));
-            if (ir.hasMetadata()) {
-                cmSection = (ColorsMetadataSection) ir.getMetadata("colors");
-            }
-        } catch (IOException | NoClassDefFoundError ignore) {
-            // this is also dumb, but FMLCommonHandler#getEffectiveSide doesn't work during test
+            Object metadata = cache.get(resourceLocation);
+            if (metadata != NOT_FOUND) cmSection = (ColorsMetadataSection) metadata;
+        } catch (ExecutionException | UncheckedExecutionException ignore) {
+            // make sure it doesn't cache a failing entry
+            cache.invalidate(resourceLocation);
         }
     }
 
@@ -41,4 +82,8 @@ public class GT_GUIColorOverride {
     public boolean sLoaded() {
         return cmSection != null;
     }
+
+    public static void onResourceManagerReload() {
+        cache.invalidateAll();
+    }
 }
diff --git a/src/main/java/gregtech/api/gui/GT_GUIContainer.java b/src/main/java/gregtech/api/gui/GT_GUIContainer.java
index 281f910d8c..efed327b46 100644
--- a/src/main/java/gregtech/api/gui/GT_GUIContainer.java
+++ b/src/main/java/gregtech/api/gui/GT_GUIContainer.java
@@ -27,7 +27,7 @@ public class GT_GUIContainer extends GuiContainer {
     public GT_GUIContainer(Container aContainer, String aGUIbackground) {
         super(aContainer);
         mGUIbackground = new ResourceLocation(mGUIbackgroundPath = aGUIbackground);
-        colorOverride = new GT_GUIColorOverride(aGUIbackground);
+        colorOverride = GT_GUIColorOverride.get(aGUIbackground);
     }
 
     protected int getTextColorOrDefault(String textType, int defaultColor) {
diff --git a/src/main/java/gregtech/api/gui/GT_GUIScreen.java b/src/main/java/gregtech/api/gui/GT_GUIScreen.java
index 470c1045a4..141f51e7c7 100644
--- a/src/main/java/gregtech/api/gui/GT_GUIScreen.java
+++ b/src/main/java/gregtech/api/gui/GT_GUIScreen.java
@@ -48,7 +48,7 @@ public abstract class GT_GUIScreen extends GuiScreen implements GT_IToolTipRende
         this.header = header;
         this.headerIcon = new GT_GuiFakeItemButton(this, 5, 5, null);
         this.mGUIbackgroundLocation = new ResourceLocation(guiTexturePath);
-        this.colorOverride = new GT_GUIColorOverride(guiTexturePath);
+        this.colorOverride = GT_GUIColorOverride.get(guiTexturePath);
         this.textColor = getTextColorOrDefault("title", 0xFF222222);
     }