Propagate exceptions in o.e.common.io.Streams. (#39042) (#39848)

This commit propagates some exceptions that were previously swallowed and also
makes sure that exceptions closing streams are either propagated if the try
block succeeded or added as suppressed exceptions otherwise.

server/src/main/java/org/elasticsearch/common/io/Streams.java

@@ -19,7 +19,6 @@
 
 package org.elasticsearch.common.io;
 
-import org.elasticsearch.core.internal.io.IOUtils;
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.io.stream.BytesStream;
 import org.elasticsearch.common.io.stream.StreamOutput;
@@ -72,26 +71,24 @@ public abstract class Streams {
     public static long copy(InputStream in, OutputStream out, byte[] buffer) throws IOException {
         Objects.requireNonNull(in, "No InputStream specified");
         Objects.requireNonNull(out, "No OutputStream specified");
-        boolean success = false;
+        // Leverage try-with-resources to close in and out so that exceptions in close() are either propagated or added as suppressed
-        try {
+        // exceptions to the main exception
-            long byteCount = 0;
+        try (InputStream in2 = in; OutputStream out2 = out) {
-            int bytesRead;
+            return doCopy(in2, out2, buffer);
-            while ((bytesRead = in.read(buffer)) != -1) {
-                out.write(buffer, 0, bytesRead);
-                byteCount += bytesRead;
-            }
-            out.flush();
-            success = true;
-            return byteCount;
-        } finally {
-            if (success) {
-                IOUtils.close(in, out);
-            } else {
-                IOUtils.closeWhileHandlingException(in, out);
-            }
         }
     }
 
+    private static long doCopy(InputStream in, OutputStream out, byte[] buffer) throws IOException {
+        long byteCount = 0;
+        int bytesRead;
+        while ((bytesRead = in.read(buffer)) != -1) {
+            out.write(buffer, 0, bytesRead);
+            byteCount += bytesRead;
+        }
+        out.flush();
+        return byteCount;
+    }
+
     /**
      * Copy the contents of the given byte array to the given OutputStream.
      * Closes the stream when done.
@@ -103,14 +100,8 @@ public abstract class Streams {
     public static void copy(byte[] in, OutputStream out) throws IOException {
         Objects.requireNonNull(in, "No input byte array specified");
         Objects.requireNonNull(out, "No OutputStream specified");
-        try {
+        try (OutputStream out2 = out) {
-            out.write(in);
+            out2.write(in);
-        } finally {
-            try {
-                out.close();
-            } catch (IOException ex) {
-                // do nothing
-            }
         }
     }
 
@@ -131,27 +122,25 @@ public abstract class Streams {
     public static int copy(Reader in, Writer out) throws IOException {
         Objects.requireNonNull(in, "No Reader specified");
         Objects.requireNonNull(out, "No Writer specified");
-        boolean success = false;
+        // Leverage try-with-resources to close in and out so that exceptions in close() are either propagated or added as suppressed
-        try {
+        // exceptions to the main exception
-            int byteCount = 0;
+        try (Reader in2 = in; Writer out2 = out) {
-            char[] buffer = new char[BUFFER_SIZE];
+            return doCopy(in2, out2);
-            int bytesRead;
-            while ((bytesRead = in.read(buffer)) != -1) {
-                out.write(buffer, 0, bytesRead);
-                byteCount += bytesRead;
-            }
-            out.flush();
-            success = true;
-            return byteCount;
-        } finally {
-            if (success) {
-                IOUtils.close(in, out);
-            } else {
-                IOUtils.closeWhileHandlingException(in, out);
-            }
         }
     }
 
+    private static int doCopy(Reader in, Writer out) throws IOException {
+        int byteCount = 0;
+        char[] buffer = new char[BUFFER_SIZE];
+        int bytesRead;
+        while ((bytesRead = in.read(buffer)) != -1) {
+            out.write(buffer, 0, bytesRead);
+            byteCount += bytesRead;
+        }
+        out.flush();
+        return byteCount;
+    }
+
     /**
      * Copy the contents of the given String to the given output Writer.
      * Closes the write when done.
@@ -163,14 +152,8 @@ public abstract class Streams {
     public static void copy(String in, Writer out) throws IOException {
         Objects.requireNonNull(in, "No input String specified");
         Objects.requireNonNull(out, "No Writer specified");
-        try {
+        try (Writer out2 = out) {
-            out.write(in);
+            out2.write(in);
-        } finally {
-            try {
-                out.close();
-            } catch (IOException ex) {
-                // do nothing
-            }
         }
     }