Provide removeAll and retainAll with predicate for MutableIterables and MutableList.

#KT-8760 Fixed

libraries/stdlib/src/kotlin/collections/MutableCollections.kt

@@ -222,10 +222,64 @@ public fun <T> MutableCollection<in T>.addAll(elements: Array<out T>) {
     addAll(elements.asList())
 }
 
+/**
+ * Removes all elements from this [MutableIterable] that match the given [predicate].
+ */
+public fun <T> MutableIterable<T>.removeAll(predicate: (T) -> Boolean): Boolean = filterInPlace(predicate, true)
+
+/**
+ * Retains only elements of this [MutableIterable] that match the given [predicate].
+ */
+public fun <T> MutableIterable<T>.retainAll(predicate: (T) -> Boolean): Boolean = filterInPlace(predicate, false)
+
+private fun <T> MutableIterable<T>.filterInPlace(predicate: (T) -> Boolean, predicateResultToRemove: Boolean): Boolean {
+    var result = false
+    with (iterator()) {
+        while (hasNext())
+            if (predicate(next()) == predicateResultToRemove) {
+                remove()
+                result = true
+            }
+    }
+    return result
+}
+
+/**
+ * Removes all elements from this [MutableList] that match the given [predicate].
+ */
+public fun <T> MutableList<T>.removeAll(predicate: (T) -> Boolean): Boolean = filterInPlace(predicate, true)
+
+/**
+ * Retains only elements of this [MutableList] that match the given [predicate].
+ */
+public fun <T> MutableList<T>.retainAll(predicate: (T) -> Boolean): Boolean = filterInPlace(predicate, false)
+
+private fun <T> MutableList<T>.filterInPlace(predicate: (T) -> Boolean, predicateResultToRemove: Boolean): Boolean {
+    var writeIndex: Int = 0
+    for (readIndex in 0..lastIndex) {
+        val element = this[readIndex]
+        if (predicate(element) == predicateResultToRemove)
+            continue
+
+        if (writeIndex != readIndex)
+            this[writeIndex] = element
+
+        writeIndex++
+    }
+    if (writeIndex < size) {
+        for (removeIndex in lastIndex downTo writeIndex)
+            removeAt(removeIndex)
+
+        return true
+    }
+    else {
+        return false
+    }
+}
+
 /**
  * Removes all elements from this [MutableCollection] that are also contained in the given [elements] collection.
  */
-
 public fun <T> MutableCollection<in T>.removeAll(elements: Iterable<T>): Boolean {
     return removeAll(elements.convertToSetForSetOperationWith(this))
 }

libraries/stdlib/src/kotlin/text/regex/RegexJVM.kt

@@ -28,12 +28,7 @@ private fun Iterable<FlagEnum>.toInt(): Int =
         this.fold(0, { value, option -> value or option.value })
 private inline fun <reified T> fromInt(value: Int): Set<T> where T : FlagEnum, T: Enum<T> =
         Collections.unmodifiableSet(EnumSet.allOf(T::class.java).apply {
-            // TODO: use removeAll with predicate
-            with (iterator()) {
-                while (hasNext())
-                    if (next().let { value and it.mask != it.value })
-                        remove()
-            }
+            retainAll { value and it.mask == it.value }
         })
 
 /**

libraries/stdlib/test/collections/MutableCollectionsTest.kt

@@ -8,12 +8,10 @@ import org.junit.Test as test
 
 class MutableCollectionTest {
 
-    // TODO: Use apply scope function
-
     @test fun addAll() {
         val data = listOf("foo", "bar")
 
-        fun assertAdd(f: MutableList<String>.() -> Unit) = assertEquals(data, arrayListOf<String>().let { it.f(); it })
+        fun assertAdd(f: MutableList<String>.() -> Unit) = assertEquals(data, arrayListOf<String>().apply(f))
 
         assertAdd { addAll(data) }
         assertAdd { addAll(data.toTypedArray()) }
@@ -26,12 +24,17 @@ class MutableCollectionTest {
         val data = listOf("bar")
         val expected = listOf("foo")
 
-        fun assertRemove(f: MutableList<String>.() -> Unit) = assertEquals(expected, arrayListOf(*content).let { it.f(); it })
+        fun assertRemove(f: MutableList<String>.() -> Unit) = assertEquals(expected, content.toArrayList().apply(f))
 
         assertRemove { removeAll(data) }
         assertRemove { removeAll(data.toTypedArray()) }
         assertRemove { removeAll(data.toTypedArray().asIterable()) }
         assertRemove { removeAll(data.asSequence()) }
+        assertRemove { removeAll { it in data } }
+        assertRemove { (this as MutableIterable<String>).removeAll { it in data } }
+
+        val predicate = { cs: CharSequence -> cs.first() == 'b' }
+        assertRemove { removeAll(predicate) }
     }
 
 
@@ -40,12 +43,17 @@ class MutableCollectionTest {
         val data = listOf("bar")
         val expected = listOf("bar", "bar")
 
-        fun assertRetain(f: MutableList<String>.() -> Unit) = assertEquals(expected, arrayListOf(*content).let { it.f(); it })
+        fun assertRetain(f: MutableList<String>.() -> Unit) = assertEquals(expected, content.toArrayList().apply(f))
 
         assertRetain { retainAll(data) }
         assertRetain { retainAll(data.toTypedArray()) }
         assertRetain { retainAll(data.toTypedArray().asIterable()) }
         assertRetain { retainAll(data.asSequence()) }
+        assertRetain { retainAll { it in data } }
+        assertRetain { (this as MutableIterable<String>).retainAll { it in data } }
+
+        val predicate = { cs: CharSequence -> cs.first() == 'b' }
+        assertRetain { retainAll(predicate) }
     }
 
 }