Refactored DeflateCompressionCodec to eliminate memory leak. Refactored GzipCompressionCodec and AbstractCompressionCodec to utilize consistent logic across compression algorithms. Resolves #392.

CHANGELOG.md

@@ -1,10 +1,14 @@
 ## Release Notes
 
+### 0.10.7
+
+This patch release fixes a [memory leak](https://github.com/jwtk/jjwt/issues/392) found in the DEFLATE compression 
+codec implementation.
+
 ### 0.10.6
 
 This patch release updates the jackson-databind version to 2.9.8 to address a critical security vulnerability in that
-library. It also updates .travis.yml to remove deprecated builds and to "trick" travis into building with Oracle
-JDK 1.7 as this library still supports that Java version even if Travis no longer does.
+library.
 
 ### 0.10.5
 

impl/src/main/java/io/jsonwebtoken/impl/compression/AbstractCompressionCodec.java

@@ -18,8 +18,12 @@ package io.jsonwebtoken.impl.compression;
 import io.jsonwebtoken.CompressionCodec;
 import io.jsonwebtoken.CompressionException;
 import io.jsonwebtoken.lang.Assert;
+import io.jsonwebtoken.lang.Objects;
 
+import java.io.ByteArrayOutputStream;
 import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
 
 /**
  * Abstract class that asserts arguments and wraps IOException with CompressionException.
@@ -28,6 +32,44 @@ import java.io.IOException;
  */
 public abstract class AbstractCompressionCodec implements CompressionCodec {
 
+    //package-protected for a point release.  This can be made protected on a minor release (0.11.0, 0.12.0, 1.0, etc).
+    //TODO: make protected on a minor release
+    interface StreamWrapper {
+        OutputStream wrap(OutputStream out) throws IOException;
+    }
+
+    //package-protected for a point release.  This can be made protected on a minor release (0.11.0, 0.12.0, 1.0, etc).
+    //TODO: make protected on a minor release
+    byte[] readAndClose(InputStream input) throws IOException {
+        byte[] buffer = new byte[512];
+        ByteArrayOutputStream out = new ByteArrayOutputStream(buffer.length);
+        int read;
+        try {
+            read = input.read(buffer); //assignment separate from loop invariant check for code coverage checks
+            while (read != -1) {
+                out.write(buffer, 0, read);
+                read = input.read(buffer);
+            }
+        } finally {
+            Objects.nullSafeClose(input);
+        }
+        return out.toByteArray();
+    }
+
+    //package-protected for a point release.  This can be made protected on a minor release (0.11.0, 0.12.0, 1.0, etc).
+    //TODO: make protected on a minor release
+    byte[] writeAndClose(byte[] payload, StreamWrapper wrapper) throws IOException {
+        ByteArrayOutputStream outputStream = new ByteArrayOutputStream(512);
+        OutputStream compressionStream = wrapper.wrap(outputStream);
+        try {
+            compressionStream.write(payload);
+            compressionStream.flush();
+        } finally {
+            Objects.nullSafeClose(compressionStream);
+        }
+        return outputStream.toByteArray();
+    }
+
     /**
      * Implement this method to do the actual work of compressing the payload
      *

impl/src/main/java/io/jsonwebtoken/impl/compression/DeflateCompressionCodec.java

@@ -15,13 +15,11 @@
  */
 package io.jsonwebtoken.impl.compression;
 
-import io.jsonwebtoken.lang.Objects;
-
-import java.io.ByteArrayOutputStream;
+import java.io.ByteArrayInputStream;
 import java.io.IOException;
-import java.util.zip.Deflater;
+import java.io.OutputStream;
 import java.util.zip.DeflaterOutputStream;
-import java.util.zip.InflaterOutputStream;
+import java.util.zip.InflaterInputStream;
 
 /**
  * Codec implementing the <a href="https://en.wikipedia.org/wiki/DEFLATE">deflate compression algorithm</a>.
@@ -32,43 +30,25 @@ public class DeflateCompressionCodec extends AbstractCompressionCodec {
 
     private static final String DEFLATE = "DEF";
 
+    private static final StreamWrapper WRAPPER = new StreamWrapper() {
+        @Override
+        public OutputStream wrap(OutputStream out) {
+            return new DeflaterOutputStream(out);
+        }
+    };
+
     @Override
     public String getAlgorithmName() {
         return DEFLATE;
     }
 
     @Override
-    public byte[] doCompress(byte[] payload) throws IOException {
-
-        Deflater deflater = new Deflater(Deflater.BEST_COMPRESSION);
-
-        ByteArrayOutputStream outputStream = null;
-        DeflaterOutputStream deflaterOutputStream = null;
-        try {
-            outputStream = new ByteArrayOutputStream();
-            deflaterOutputStream = new DeflaterOutputStream(outputStream, deflater, true);
-
-            deflaterOutputStream.write(payload, 0, payload.length);
-            deflaterOutputStream.flush();
-            return outputStream.toByteArray();
-        } finally {
-            Objects.nullSafeClose(outputStream, deflaterOutputStream);
-        }
+    protected byte[] doCompress(byte[] payload) throws IOException {
+        return writeAndClose(payload, WRAPPER);
     }
 
     @Override
-    public byte[] doDecompress(byte[] compressed) throws IOException {
-        InflaterOutputStream inflaterOutputStream = null;
-        ByteArrayOutputStream decompressedOutputStream = null;
-
-        try {
-            decompressedOutputStream = new ByteArrayOutputStream();
-            inflaterOutputStream = new InflaterOutputStream(decompressedOutputStream);
-            inflaterOutputStream.write(compressed);
-            inflaterOutputStream.flush();
-            return decompressedOutputStream.toByteArray();
-        } finally {
-            Objects.nullSafeClose(decompressedOutputStream, inflaterOutputStream);
-        }
+    protected byte[] doDecompress(byte[] compressed) throws IOException {
+        return readAndClose(new InflaterInputStream(new ByteArrayInputStream(compressed)));
     }
 }

impl/src/main/java/io/jsonwebtoken/impl/compression/GzipCompressionCodec.java

@@ -16,11 +16,10 @@
 package io.jsonwebtoken.impl.compression;
 
 import io.jsonwebtoken.CompressionCodec;
-import io.jsonwebtoken.lang.Objects;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
+import java.io.OutputStream;
 import java.util.zip.GZIPInputStream;
 import java.util.zip.GZIPOutputStream;
 
@@ -33,43 +32,25 @@ public class GzipCompressionCodec extends AbstractCompressionCodec implements Co
 
     private static final String GZIP = "GZIP";
 
+    private static final StreamWrapper WRAPPER = new StreamWrapper() {
+        @Override
+        public OutputStream wrap(OutputStream out) throws IOException {
+            return new GZIPOutputStream(out);
+        }
+    };
+
     @Override
     public String getAlgorithmName() {
         return GZIP;
     }
 
     @Override
-    protected byte[] doDecompress(byte[] compressed) throws IOException {
-        byte[] buffer = new byte[512];
-
-        ByteArrayOutputStream outputStream = null;
-        GZIPInputStream gzipInputStream = null;
-        ByteArrayInputStream inputStream = null;
-
-        try {
-            inputStream = new ByteArrayInputStream(compressed);
-            gzipInputStream = new GZIPInputStream(inputStream);
-            outputStream = new ByteArrayOutputStream();
-            int read = gzipInputStream.read(buffer);
-            while (read != -1) {
-                outputStream.write(buffer, 0, read);
-                read = gzipInputStream.read(buffer);
-            }
-            return outputStream.toByteArray();
-        } finally {
-            Objects.nullSafeClose(inputStream, gzipInputStream, outputStream);
-        }
-    }
-
     protected byte[] doCompress(byte[] payload) throws IOException {
-        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
-        GZIPOutputStream compressorOutputStream = new GZIPOutputStream(outputStream, true);
-        try {
-            compressorOutputStream.write(payload, 0, payload.length);
-            compressorOutputStream.finish();
-            return outputStream.toByteArray();
-        } finally {
-            Objects.nullSafeClose(compressorOutputStream, outputStream);
-        }
+        return writeAndClose(payload, WRAPPER);
+    }
+
+    @Override
+    protected byte[] doDecompress(byte[] compressed) throws IOException {
+        return readAndClose(new GZIPInputStream(new ByteArrayInputStream(compressed)));
     }
 }