Fix bugs and improve performance of ProxyStream

core/constants/src/mill/constants/InputPumper.java

@@ -4,7 +4,7 @@
 import java.io.OutputStream;
 import java.util.function.Supplier;
 
-/// A `Runnable` that reads from `src` and writes to `dest`.
+/** A `Runnable` that reads from `src` and writes to `dest`. */
 public class InputPumper implements Runnable {
   private final Supplier<InputStream> src0;
   private final Supplier<OutputStream> dest0;
@@ -15,7 +15,7 @@ public class InputPumper implements Runnable {
   /// and there is nothing to read, [it can unnecessarily delay the JVM exit by 350ms](
   ///
   // https://stackoverflow.com/questions/48951611/blocking-on-stdin-makes-java-process-take-350ms-more-to-exit)
-  private final Boolean checkAvailable;
+  private final boolean checkAvailable;
 
   public InputPumper(
       Supplier<InputStream> src, Supplier<OutputStream> dest, Boolean checkAvailable) {
@@ -28,29 +28,29 @@ public InputPumper(
 
   @Override
   public void run() {
-    InputStream src = src0.get();
-    OutputStream dest = dest0.get();
+    var src = src0.get();
+    var dest = dest0.get();
 
-    byte[] buffer = new byte[1024];
+    var buffer = new byte[1024 /* 1kb */];
     try {
       while (running) {
         if (checkAvailable && src.available() == 0)
           //noinspection BusyWait
           Thread.sleep(1);
         else {
-          int n;
+          int bytesRead;
           try {
-            n = src.read(buffer);
+            bytesRead = src.read(buffer);
           } catch (Exception e) {
-            n = -1;
+            bytesRead = -1;
           }
-          if (n == -1) running = false;
-          else if (n == 0)
+          if (bytesRead == -1) running = false;
+          else if (bytesRead == 0)
             //noinspection BusyWait
             Thread.sleep(1);
           else {
             try {
-              dest.write(buffer, 0, n);
+              dest.write(buffer, 0, bytesRead);
               dest.flush();
             } catch (java.io.IOException e) {
               running = false;