[Feature] API to modify speed of DiggerItems

src/main/java/org/betterx/bclib/api/v2/DiggerItemSpeed.java

@@ -0,0 +1,35 @@
+package org.betterx.bclib.api.v2;
+
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.level.block.state.BlockState;
+
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Optional;
+
+public class DiggerItemSpeed {
+    public static final List<SpeedModifier> modifiers = new LinkedList<>();
+
+    @FunctionalInterface
+    public interface SpeedModifier {
+        Optional<Float> calculateSpeed(ItemStack stack, BlockState state, float initialSpeed, float currentSpeed);
+    }
+
+    public static void addModifier(SpeedModifier mod) {
+        modifiers.add(mod);
+    }
+
+    public static Optional<Float> getModifiedSpeed(ItemStack stack, BlockState state, float initialSpeed) {
+        float currentSpeed = initialSpeed;
+        Optional<Float> speed = Optional.empty();
+        for (SpeedModifier mod : modifiers) {
+            Optional<Float> res = mod.calculateSpeed(stack, state, initialSpeed, currentSpeed);
+            if (res.isPresent()) {
+                currentSpeed = res.get();
+                speed = res;
+            }
+        }
+
+        return speed;
+    }
+}

src/main/java/org/betterx/bclib/mixin/common/DiggerItemMixin.java

@@ -0,0 +1,25 @@
+package org.betterx.bclib.mixin.common;
+
+import org.betterx.bclib.api.v2.DiggerItemSpeed;
+
+import net.minecraft.world.item.DiggerItem;
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.level.block.state.BlockState;
+
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
+
+import java.util.Optional;
+
+@Mixin(DiggerItem.class)
+public class DiggerItemMixin {
+    @Inject(method = "getDestroySpeed", at = @At(value = "RETURN"), cancellable = true)
+    void bn_getDestroySpeed(ItemStack stack, BlockState state, CallbackInfoReturnable<Float> cir) {
+        final Optional<Float> newSpeed = DiggerItemSpeed.getModifiedSpeed(stack, state, cir.getReturnValue());
+        if (newSpeed.isPresent()) {
+            cir.setReturnValue(newSpeed.get());
+        }
+    }
+}

src/main/resources/bclib.mixins.common.json

@@ -17,6 +17,7 @@
     "CraftingMenuMixin",
     "DedicatedServerPropertiesMixin",
     "DiggerItemAccessor",
+    "DiggerItemMixin",
     "EnchantingTableBlockMixin",
     "ItemStackMixin",
     "LayerLightSectionStorageMixin",