2 files changed, 238 insertions, 0 deletions
diff --git a/src/main/java/me/lucko/fabric/api/permissions/v0/PermissionCheckEvent.java b/src/main/java/me/lucko/fabric/api/permissions/v0/PermissionCheckEvent.java
new file mode 100644
index 0000000..42b5b63
--- /dev/null
+++ b/src/main/java/me/lucko/fabric/api/permissions/v0/PermissionCheckEvent.java
@@ -0,0 +1,52 @@
+/*
+ * This file is part of fabric-permissions-api, licensed under the MIT License.
+ *
+ *  Copyright (c) lucko (Luck) <[email protected]>
+ *  Copyright (c) contributors
+ *
+ *  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.
+ */
+
+package me.lucko.fabric.api.permissions.v0;
+
+import net.fabricmc.fabric.api.event.Event;
+import net.fabricmc.fabric.api.event.EventFactory;
+import net.fabricmc.fabric.api.util.TriState;
+import net.minecraft.command.CommandSource;
+
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Simple permissions check event for {@link CommandSource}s.
+ */
+public interface PermissionCheckEvent {
+
+    Event<PermissionCheckEvent> EVENT = EventFactory.createArrayBacked(PermissionCheckEvent.class, (callbacks) -> (source, permission) -> {
+        for (PermissionCheckEvent callback : callbacks) {
+            TriState state = callback.onPermissionCheck(source, permission);
+            if (state != TriState.DEFAULT) {
+                return state;
+            }
+        }
+        return TriState.DEFAULT;
+    });
+
+    @NotNull TriState onPermissionCheck(@NotNull CommandSource source, @NotNull String permission);
+
+}
diff --git a/src/main/java/me/lucko/fabric/api/permissions/v0/Permissions.java b/src/main/java/me/lucko/fabric/api/permissions/v0/Permissions.java
new file mode 100644
index 0000000..9fab02b
--- /dev/null
+++ b/src/main/java/me/lucko/fabric/api/permissions/v0/Permissions.java
@@ -0,0 +1,186 @@
+/*
+ * This file is part of fabric-permissions-api, licensed under the MIT License.
+ *
+ *  Copyright (c) lucko (Luck) <[email protected]>
+ *  Copyright (c) contributors
+ *
+ *  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.
+ */
+
+package me.lucko.fabric.api.permissions.v0;
+
+import net.fabricmc.fabric.api.util.TriState;
+import net.minecraft.command.CommandSource;
+import net.minecraft.entity.Entity;
+import net.minecraft.server.command.ServerCommandSource;
+
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Objects;
+import java.util.function.Predicate;
+
+/**
+ * A simple permissions API.
+ */
+public interface Permissions {
+
+    /**
+     * Gets the {@link TriState state} of a {@code permission} for the given source.
+     *
+     * @param source the source
+     * @param permission the permission
+     * @return the state of the permission
+     */
+    static @NotNull TriState getPermissionValue(@NotNull CommandSource source, @NotNull String permission) {
+        Objects.requireNonNull(source, "source");
+        Objects.requireNonNull(permission, "permission");
+        return PermissionCheckEvent.EVENT.invoker().onPermissionCheck(source, permission);
+    }
+
+    /**
+     * Performs a permission check, falling back to the {@code defaultValue} if the resultant
+     * state is {@link TriState#DEFAULT}.
+     *
+     * @param source the source to perform the check for
+     * @param permission the permission to check
+     * @param defaultValue the default value to use if nothing has been set
+     * @return the result of the permission check
+     */
+    static boolean check(@NotNull CommandSource source, @NotNull String permission, boolean defaultValue) {
+        return getPermissionValue(source, permission).orElse(defaultValue);
+    }
+
+    /**
+     * Performs a permission check, falling back to requiring the {@code defaultRequiredLevel}
+     * if the resultant state is {@link TriState#DEFAULT}.
+     *
+     * @param source the source to perform the check for
+     * @param permission the permission to check
+     * @param defaultRequiredLevel the required permission level to check for as a fallback
+     * @return the result of the permission check
+     */
+    static boolean check(@NotNull CommandSource source, @NotNull String permission, int defaultRequiredLevel) {
+        return getPermissionValue(source, permission).orElseGet(() -> source.hasPermissionLevel(defaultRequiredLevel));
+    }
+
+    /**
+     * Performs a permission check, falling back to {@code false} if the resultant state
+     * is {@link TriState#DEFAULT}.
+     *
+     * @param source the source to perform the check for
+     * @param permission the permission to check
+     * @return the result of the permission check
+     */
+    static boolean check(@NotNull CommandSource source, @NotNull String permission) {
+        return getPermissionValue(source, permission).orElse(false);
+    }
+
+    /**
+     * Creates a predicate which returns the result of performing a permission check,
+     * falling back to the {@code defaultValue} if the resultant state is {@link TriState#DEFAULT}.
+     *
+     * @param permission the permission to check
+     * @param defaultValue the default value to use if nothing has been set
+     * @return a predicate that will perform the permission check
+     */
+    static @NotNull Predicate<ServerCommandSource> require(@NotNull String permission, boolean defaultValue) {
+        Objects.requireNonNull(permission, "permission");
+        return player -> check(player, permission, defaultValue);
+    }
+
+    /**
+     * Creates a predicate which returns the result of performing a permission check,
+     * falling back to requiring the {@code defaultRequiredLevel} if the resultant state is
+     * {@link TriState#DEFAULT}.
+     *
+     * @param permission the permission to check
+     * @param defaultRequiredLevel the required permission level to check for as a fallback
+     * @return a predicate that will perform the permission check
+     */
+    static @NotNull Predicate<ServerCommandSource> require(@NotNull String permission, int defaultRequiredLevel) {
+        Objects.requireNonNull(permission, "permission");
+        return player -> check(player, permission, defaultRequiredLevel);
+    }
+
+    /**
+     * Creates a predicate which returns the result of performing a permission check,
+     * falling back to {@code false} if the resultant state is {@link TriState#DEFAULT}.
+     *
+     * @param permission the permission to check
+     * @return a predicate that will perform the permission check
+     */
+    static @NotNull Predicate<ServerCommandSource> require(@NotNull String permission) {
+        Objects.requireNonNull(permission, "permission");
+        return player -> check(player, permission);
+    }
+
+    /**
+     * Gets the {@link TriState state} of a {@code permission} for the given entity.
+     *
+     * @param entity the entity
+     * @param permission the permission
+     * @return the state of the permission
+     */
+    static @NotNull TriState getPermissionValue(@NotNull Entity entity, @NotNull String permission) {
+        Objects.requireNonNull(entity, "entity");
+        return getPermissionValue(entity.getCommandSource(), permission);
+    }
+
+    /**
+     * Performs a permission check, falling back to the {@code defaultValue} if the resultant
+     * state is {@link TriState#DEFAULT}.
+     *
+     * @param entity the entity to perform the check for
+     * @param permission the permission to check
+     * @param defaultValue the default value to use if nothing has been set
+     * @return the result of the permission check
+     */
+    static boolean check(@NotNull Entity entity, @NotNull String permission, boolean defaultValue) {
+        Objects.requireNonNull(entity, "entity");
+        return check(entity.getCommandSource(), permission, defaultValue);
+    }
+
+    /**
+     * Performs a permission check, falling back to requiring the {@code defaultRequiredLevel}
+     * if the resultant state is {@link TriState#DEFAULT}.
+     *
+     * @param entity the entity to perform the check for
+     * @param permission the permission to check
+     * @param defaultRequiredLevel the required permission level to check for as a fallback
+     * @return the result of the permission check
+     */
+    static boolean check(@NotNull Entity entity, @NotNull String permission, int defaultRequiredLevel) {
+        Objects.requireNonNull(entity, "entity");
+        return check(entity.getCommandSource(), permission, defaultRequiredLevel);
+    }
+
+    /**
+     * Performs a permission check, falling back to {@code false} if the resultant state
+     * is {@link TriState#DEFAULT}.
+     *
+     * @param entity the entity to perform the check for
+     * @param permission the permission to check
+     * @return the result of the permission check
+     */
+    static boolean check(@NotNull Entity entity, @NotNull String permission) {
+        Objects.requireNonNull(entity, "entity");
+        return check(entity.getCommandSource(), permission);
+    }
+
+}