Add Collection.asImmutable for commonMain

mirai-core-utils/src/commonMain/kotlin/Collections.kt

@@ -71,4 +71,16 @@ public fun <K, V : R, R> Map<K, V>.getOrDefault(key: K, default: R): R = getOrEl
 
 @Suppress("EXTENSION_SHADOWED_BY_MEMBER") // JDK 1.8
 @Deprecated("", ReplaceWith("getOrPut(key) { value }"))
-public fun <K, V> MutableMap<K, V>.putIfAbsent(key: K, value: V): V = getOrPut(key) { value }
+public fun <K, V> MutableMap<K, V>.putIfAbsent(key: K, value: V): V = getOrPut(key) { value }
+
+/**
+ * Returns a [List] that cannot be cast to [MutableList] to modify it.
+ */
+public expect fun <T> List<T>.asImmutable(): List<T>
+
+/**
+ * Returns a [Collection] that cannot be cast to [MutableCollection] to modify it.
+ */
+public expect fun <T> Collection<T>.asImmutable(): Collection<T>
+
+public expect fun <T> Set<T>.asImmutable(): Set<T>

mirai-core-utils/src/jvmBaseMain/kotlin/Collections.kt

@@ -14,26 +14,17 @@ import java.util.concurrent.CopyOnWriteArraySet
 import kotlin.reflect.KClass
 
 
-public fun <T> Collection<T>.asImmutable(): Collection<T> {
-    return when (this) {
-        is List<T> -> asImmutable()
-        is Set<T> -> asImmutable()
-        else -> Collections.unmodifiableCollection(this)
-    }
-}
-
-@Suppress("NOTHING_TO_INLINE")
-public inline fun <T> Collection<T>.asImmutableStrict(): Collection<T> {
+public actual fun <T> Collection<T>.asImmutable(): Collection<T> {
     return Collections.unmodifiableCollection(this)
 }
 
 @Suppress("NOTHING_TO_INLINE")
-public inline fun <T> List<T>.asImmutable(): List<T> {
+public actual inline fun <T> List<T>.asImmutable(): List<T> {
     return Collections.unmodifiableList(this)
 }
 
 @Suppress("NOTHING_TO_INLINE")
-public inline fun <T> Set<T>.asImmutable(): Set<T> {
+public actual inline fun <T> Set<T>.asImmutable(): Set<T> {
     return Collections.unmodifiableSet(this)
 }
 

mirai-core-utils/src/nativeMain/kotlin/Collections.kt

@@ -90,4 +90,23 @@ public actual interface MutableQueue<E> : MutableCollection<E> {
     public actual fun offer(element: E): Boolean
 
 
-}
+}
+
+/**
+ * Returns a [List] that cannot be cast to [MutableList] to modify it.
+ */
+public actual fun <T> List<T>.asImmutable(): List<T> = ImmutableList(this)
+public actual fun <T> Collection<T>.asImmutable(): Collection<T> = ImmutableCollection(this)
+public actual fun <T> Set<T>.asImmutable(): Set<T> = ImmutableSet(this)
+
+internal class ImmutableList<T>(
+    private val delegate: List<T>
+) : List<T> by delegate
+
+internal class ImmutableCollection<T>(
+    private val delegate: Collection<T>
+) : Collection<T> by delegate
+
+internal class ImmutableSet<T>(
+    private val delegate: Set<T>
+) : Set<T> by delegate