Fix empty chunk view creation

Author: Sergey Mashkov

CHANGELOG.md

@@ -8,6 +8,8 @@
 - Added a cpointer constructor to native IoBuffer so that IoBuffer can be used to read AND write on a memory chunk 
 - Made ByteChannel pass original cause from the owner job
 - Fixed reading UTF-8 lines
+- Fixed empty chunk view creation
+- Utility functions takeWhile* improvements
 
 # 0.1.0
 > Published 15 Nov 2018

kotlinx-io-js/src/main/kotlin/kotlinx/io/core/IoBufferJS.kt

@@ -957,6 +957,8 @@ actual class IoBuffer internal constructor(
     actual fun isExclusivelyOwned(): Boolean = refCount == 1
 
     actual fun makeView(): IoBuffer {
+        if (this === Empty) return this
+
         val o = origin ?: this
         o.acquire()
 

kotlinx-io-jvm/src/main/kotlin/kotlinx/io/core/IoBufferJVM.kt

@@ -739,6 +739,8 @@ actual class IoBuffer private constructor(
      * Creates a new view to the same actual buffer with independant read and write positions and gaps
      */
     actual fun makeView(): IoBuffer {
+        if (this === Empty) return this
+
         val newOrigin = origin ?: this
         newOrigin.acquire()
 
@@ -863,12 +865,16 @@ actual class IoBuffer private constructor(
     }
 
     private fun releaseRefCount(): Boolean {
-        if (this === Empty) throw IllegalArgumentException("Attempted to release empty")
+        if (this === Empty) {
+            throw IllegalArgumentException("Attempted to release empty")
+        }
         while (true) {
             val value = refCount
             val newValue = value - 1
 
-            if (value == 0L) throw IllegalStateException("Unable to release: already released")
+            if (value == 0L) {
+                throw IllegalStateException("Unable to release: already released")
+            }
             if (RefCount.compareAndSet(this, value, newValue)) {
                 return newValue == 0L
             }

kotlinx-io-native/src/main/kotlin/kotlinx/io/core/IoBufferNative.kt

@@ -980,6 +980,8 @@ actual class IoBuffer internal constructor(
     actual fun isExclusivelyOwned(): Boolean = refCount == 1
 
     actual fun makeView(): IoBuffer {
+        if (this === Empty) return this
+
         val o = origin ?: this
         o.acquire()