Initial commit

18 files changed, 692 insertions, 0 deletions

diff --git a/.editorconfig b/.editorconfig
new file mode 100644
index 0000000..7dfb629
--- /dev/null
+++ b/.editorconfig
@@ -0,0 +1,14 @@
+[*]
+charset = utf-8
+end_of_line = lf
+indent_size = 4
+indent_style = space
+insert_final_newline = true
+max_line_length = 120
+tab_width = 4
+
+[*.json]
+indent_size = 2
+
+[*.properties]
+ij_properties_keep_blank_lines = true
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..c476faf
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,40 @@
+# gradle
+
+.gradle/
+build/
+out/
+classes/
+
+# eclipse
+
+*.launch
+
+# idea
+
+.idea/
+*.iml
+*.ipr
+*.iws
+
+# vscode
+
+.settings/
+.vscode/
+bin/
+.classpath
+.project
+
+# macos
+
+*.DS_Store
+
+# fabric
+
+run/
+
+# java
+
+hs_err_*.log
+replay_*.log
+*.hprof
+*.jfr
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..ff7c969
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2023 NotNite
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..bdc2f89
--- /dev/null
+++ b/README.md
@@ -0,0 +1,37 @@
+# Gloppers!
+
+Gloppers (**gl**ob h**oppers**) is a Minecraft mod that lets you filter your hoppers by renaming them with glob patterns.
+
+The idea comes from [LiveOverflow's Minecraft lets play](https://www.youtube.com/playlist?list=PLhixgUqwRTjwvBI-hmbZ2rpkAl4lutnJG), where these were silently implemented on his server to make his storage system easier to build.
+
+![A screenshot of a hopper's inventory, with the name "!*_ore,anvil"](./img/demo.png)
+
+## Usage
+
+First, install the mod. This mod is serverside only and will do nothing on the client (unless you're in singleplayer).
+
+Once it's installed, rename a hopper in an anvil, prefixing with an exclamation mark. Add globs matching the IDs of the items you want to filter for, separated by commas.
+
+Some example patterns:
+
+- `!*_ore` - Matches all ores
+- `!iron_*` - Matches all iron items
+- `!totem_of_undying` - Matches only the Totem of Undying
+- `!*oak*,*cherry*` - Matches all oak and cherry wood items
+
+Note that you must use the internal identifier of the items, and not the item's display name (e.g. `writable_book` instead of `Book and Quill`). Don't add the namespace (the "minecraft" part).
+
+## Advantages over vanilla
+
+- Only materials required to use are iron and wood (no redstone)
+- 1x1x1 footprint, compared to the popular 4x3x1 design
+- Ability to filter unstackable items
+- No junk items required
+
+## Usage in storage systems
+
+Gloppers are most useful in storage systems. Instead of requiring redstone circuits that take up space, you can instead just design it like so:
+
+![A 2x4x1 schematic of a storage system, with a top row of hoppers, and a bottom row of one glopper and one chest](./img/storage.png)
+
+Items will only be sucked up from the top row to the bottom glopper if the pattern is matched.
diff --git a/build.gradle b/build.gradle
new file mode 100644
index 0000000..2184f95
--- /dev/null
+++ b/build.gradle
@@ -0,0 +1,58 @@
+plugins {
+    id "fabric-loom" version "1.2-SNAPSHOT"
+    id "org.jetbrains.kotlin.jvm" version "1.8.22"
+}
+
+version = project.mod_version
+group = project.maven_group
+
+base {
+    archivesName = project.archives_base_name
+}
+
+repositories {
+    maven { url "https://jitpack.io" }
+}
+
+dependencies {
+    minecraft "com.mojang:minecraft:${project.minecraft_version}"
+    mappings "net.fabricmc:yarn:${project.yarn_mappings}:v2"
+    modImplementation "net.fabricmc:fabric-loader:${project.loader_version}"
+
+    modImplementation "net.fabricmc.fabric-api:fabric-api:${project.fabric_version}"
+    modImplementation "net.fabricmc:fabric-language-kotlin:${project.fabric_kotlin_version}"
+
+    implementation "com.github.LlamaLad7:MixinExtras:${project.mixinextras_version}"
+    annotationProcessor "com.github.LlamaLad7:MixinExtras:${project.mixinextras_version}"
+}
+
+processResources {
+    inputs.property "version", project.version
+
+    filesMatching("fabric.mod.json") {
+        expand "version": project.version
+    }
+}
+
+tasks.withType(JavaCompile).configureEach {
+    it.options.release = 17
+}
+
+tasks.withType(org.jetbrains.kotlin.gradle.tasks.KotlinCompile).all {
+    kotlinOptions {
+        jvmTarget = 17
+    }
+}
+
+java {
+    withSourcesJar()
+
+    sourceCompatibility = JavaVersion.VERSION_17
+    targetCompatibility = JavaVersion.VERSION_17
+}
+
+jar {
+    from("LICENSE") {
+        rename { "${it}_${project.archivesBaseName}" }
+    }
+}
diff --git a/gradle.properties b/gradle.properties
new file mode 100644
index 0000000..1328e21
--- /dev/null
+++ b/gradle.properties
@@ -0,0 +1,15 @@
+org.gradle.jvmargs=-Xmx1G
+org.gradle.parallel=true
+
+minecraft_version=1.20
+yarn_mappings=1.20+build.1
+# While we build off of 0.14.21, the dependency is set as 0.14.19 to work with Quilt
+loader_version=0.14.21
+fabric_kotlin_version=1.9.5+kotlin.1.8.22
+
+mod_version=1.0.0
+maven_group=com.notnite
+archives_base_name=gloppers
+
+fabric_version=0.83.0+1.20
+mixinextras_version=0.1.1
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
new file mode 100644
index 0000000..c1962a7
--- /dev/null
+++ b/gradle/wrapper/gradle-wrapper.jar
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
new file mode 100644
index 0000000..37aef8d
--- /dev/null
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -0,0 +1,6 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.1.1-bin.zip
+networkTimeout=10000
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
diff --git a/gradlew b/gradlew
new file mode 100644
index 0000000..aeb74cb
--- /dev/null
+++ b/gradlew
@@ -0,0 +1,245 @@
+#!/bin/sh
+
+#
+# Copyright © 2015-2021 the original authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+# This is normally unused
+# shellcheck disable=SC2034
+APP_BASE_NAME=${0##*/}
+APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&2
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD=$JAVA_HOME/jre/sh/java
+    else
+        JAVACMD=$JAVA_HOME/bin/java
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC3045
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC3045
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command;
+#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
+#     shell script including quotes and variable substitutions, so put them in
+#     double quotes to make sure that they get re-expanded; and
+#   * put everything else in single quotes, so that it's not re-expanded.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"
diff --git a/gradlew.bat b/gradlew.bat
new file mode 100644
index 0000000..93e3f59
--- /dev/null
+++ b/gradlew.bat
@@ -0,0 +1,92 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%"=="" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if %ERRORLEVEL% equ 0 goto execute
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if %ERRORLEVEL% equ 0 goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega
diff --git a/img/demo.png b/img/demo.png
new file mode 100644
index 0000000..9f8a21f
--- /dev/null
+++ b/img/demo.png
diff --git a/img/storage.png b/img/storage.png
new file mode 100644
index 0000000..48e6ab7
--- /dev/null
+++ b/img/storage.png
diff --git a/settings.gradle b/settings.gradle
new file mode 100644
index 0000000..f7854b3
--- /dev/null
+++ b/settings.gradle
@@ -0,0 +1,10 @@
+pluginManagement {
+    repositories {
+        maven {
+            name = "Fabric"
+            url = "https://maven.fabricmc.net/"
+        }
+        mavenCentral()
+        gradlePluginPortal()
+    }
+}
diff --git a/src/main/java/com/notnite/gloppers/mixin/HopperBlockEntityMixin.java b/src/main/java/com/notnite/gloppers/mixin/HopperBlockEntityMixin.java
new file mode 100644
index 0000000..78468ac
--- /dev/null
+++ b/src/main/java/com/notnite/gloppers/mixin/HopperBlockEntityMixin.java
@@ -0,0 +1,65 @@
+package com.notnite.gloppers.mixin;
+
+import com.notnite.gloppers.Gloppers;
+import net.fabricmc.api.EnvType;
+import net.fabricmc.api.Environment;
+import net.minecraft.block.entity.Hopper;
+import net.minecraft.block.entity.HopperBlockEntity;
+import net.minecraft.inventory.Inventory;
+import net.minecraft.item.ItemStack;
+import net.minecraft.util.math.Direction;
+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.Redirect;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
+
+@Environment(EnvType.SERVER)
+@Mixin(HopperBlockEntity.class)
+public class HopperBlockEntityMixin {
+    private static int dirtySlotState = 0;
+
+    // We can't decrement the item stack before it gets passed to transfer, because we may not be allowed to transfer,
+    // eating an item. We know removeStack will get called immediately before transfer, so while it's messy, we can use
+    // a static variable to keep track of what slot we're removing from.
+    @Redirect(
+        method = "insert",
+        at = @At(value = "INVOKE", target = "Lnet/minecraft/inventory/Inventory;removeStack(II)Lnet/minecraft/item/ItemStack;")
+    )
+    private static ItemStack insert$gloppersRemoveStack(Inventory instance, int slot, int amount) {
+        dirtySlotState = slot;
+        return instance.getStack(slot);
+    }
+
+    // This works by mixing into the call of HopperBlockEntity::transfer and returning a stubbed item stack if it's not
+    // allowed to transfer. I wanted to instead insert a continue statement into the for loop, but I couldn't figure out
+    // a good way to do that.
+    @Redirect(
+        method = "insert",
+        at = @At(value = "INVOKE", target = "Lnet/minecraft/block/entity/HopperBlockEntity;transfer(Lnet/minecraft/inventory/Inventory;Lnet/minecraft/inventory/Inventory;Lnet/minecraft/item/ItemStack;Lnet/minecraft/util/math/Direction;)Lnet/minecraft/item/ItemStack;")
+    )
+    private static ItemStack insert$gloppersTransfer(
+        Inventory from, Inventory to, ItemStack stack, Direction side
+    ) {
+        if (!Gloppers.INSTANCE.canTransfer(to, stack)) {
+            // The return value of this is only used to check if it's empty, and if so, returns that it succeeded.
+            // We can just return the item stack we were given, as we didn't remove from it.
+            return stack;
+        }
+
+        // Make sure to remove the item here, because we didn't in the actual call.
+        return HopperBlockEntity.transfer(from, to, from.removeStack(dirtySlotState, 1), side);
+    }
+
+    // This handles the case where a hopper extracts from a hopper above it (such as two anvils facing forward, stacked
+    // on top of one another).
+    @Inject(
+        method = "extract(Lnet/minecraft/block/entity/Hopper;Lnet/minecraft/inventory/Inventory;ILnet/minecraft/util/math/Direction;)Z",
+        at = @At("HEAD"),
+        cancellable = true
+    )
+    private static void extract(Hopper hopper, Inventory inventory, int slot, Direction side, CallbackInfoReturnable<Boolean> cir) {
+        var item = inventory.getStack(slot);
+        if (!Gloppers.INSTANCE.canTransfer(hopper, item)) cir.setReturnValue(false);
+    }
+}
diff --git a/src/main/kotlin/com/notnite/gloppers/Gloppers.kt b/src/main/kotlin/com/notnite/gloppers/Gloppers.kt
new file mode 100644
index 0000000..bdea779
--- /dev/null
+++ b/src/main/kotlin/com/notnite/gloppers/Gloppers.kt
@@ -0,0 +1,41 @@
+package com.notnite.gloppers
+
+import net.fabricmc.api.DedicatedServerModInitializer
+import net.minecraft.block.entity.HopperBlockEntity
+import net.minecraft.inventory.Inventory
+import net.minecraft.item.ItemStack
+
+object Gloppers : DedicatedServerModInitializer {
+    override fun onInitializeServer() {}
+
+    private fun matchesGlob(glob: String, str: String): Boolean {
+        val regex = glob
+            .replace(".", "\\.")
+            .replace("*", ".*")
+            .replace("?", ".")
+        return str.matches(regex.toRegex())
+    }
+
+    fun canTransfer(to: Inventory, stack: ItemStack): Boolean {
+        if (to is HopperBlockEntity) {
+            val hopperName = to.name.copyContentOnly().string
+            val itemName = stack.registryEntry.key.get().value.path
+
+            if (hopperName.startsWith("!")) {
+                val globs = hopperName.substring(1).split(",")
+                for (glob in globs) {
+                    if (matchesGlob(glob, itemName)) {
+                        // Glob matched, transfer
+                        return true
+                    }
+                }
+
+                // No globs matched, so don't transfer
+                return false
+            }
+        }
+
+        // Doesn't have a glob, so transfer
+        return true
+    }
+}
diff --git a/src/main/resources/assets/gloppers/icon.png b/src/main/resources/assets/gloppers/icon.png
new file mode 100644
index 0000000..25b7fb6
--- /dev/null
+++ b/src/main/resources/assets/gloppers/icon.png
diff --git a/src/main/resources/fabric.mod.json b/src/main/resources/fabric.mod.json
new file mode 100644
index 0000000..7599de5
--- /dev/null
+++ b/src/main/resources/fabric.mod.json
@@ -0,0 +1,37 @@
+{
+  "schemaVersion": 1,
+  "id": "gloppers",
+  "version": "${version}",
+  "name": "Gloppers!",
+  "description": "Filter your hoppers by renaming them with glob patterns.",
+  "authors": [
+    "NotNite"
+  ],
+  "contact": {
+    "sources": "https://github.com/NotNite/gloppers"
+  },
+  "license": "MIT",
+  "icon": "assets/gloppers/icon.png",
+  "environment": "server",
+  "entrypoints": {
+    "server": [
+      {
+        "value": "com.notnite.gloppers.Gloppers",
+        "adapter": "kotlin"
+      }
+    ]
+  },
+  "mixins": [
+    {
+      "environment": "server",
+      "config": "gloppers.mixins.json"
+    }
+  ],
+  "depends": {
+    "fabricloader": ">=0.14.19",
+    "minecraft": "~1.20",
+    "java": ">=17",
+    "fabric-api": "*",
+    "fabric-language-kotlin": ">=1.8.22"
+  }
+}
diff --git a/src/main/resources/gloppers.mixins.json b/src/main/resources/gloppers.mixins.json
new file mode 100644
index 0000000..6ddce8d
--- /dev/null
+++ b/src/main/resources/gloppers.mixins.json
@@ -0,0 +1,11 @@
+{
+  "required": true,
+  "package": "com.notnite.gloppers.mixin",
+  "compatibilityLevel": "JAVA_17",
+  "server": [
+    "HopperBlockEntityMixin"
+  ],
+  "injectors": {
+    "defaultRequire": 1
+  }
+}