Input streams returned by DecompressingEntity.getContent() should

support mark(int) and reset() if the underlying stream does

- Pass calls to the underlying InputStream for mark(int)
- Pass calls to the underlying InputStream for reset()
- LazyDecompressingInputStream extends FilterInputStream
- Reimplement internals fluently
- Reuse Closer.close(Closeable)
- Tested locally with git master 5.3-beta2-SNAPSHOT

httpclient5/src/main/java/org/apache/hc/client5/http/entity/LazyDecompressingInputStream.java

@@ -26,15 +26,18 @@
  */
 package org.apache.hc.client5.http.entity;
 
+import java.io.FilterInputStream;
 import java.io.IOException;
 import java.io.InputStream;
+import java.io.UncheckedIOException;
+
+import org.apache.hc.core5.io.Closer;
 
 /**
- * Lazy init InputStream wrapper.
+ * Lazy initializes from an {@link InputStream} wrapper.
  */
-class LazyDecompressingInputStream extends InputStream {
+class LazyDecompressingInputStream extends FilterInputStream {
 
-    private final InputStream wrappedStream;
     private final InputStreamFactory inputStreamFactory;
 
     private InputStream wrapperStream;
@@ -42,38 +45,35 @@ class LazyDecompressingInputStream extends InputStream {
     public LazyDecompressingInputStream(
             final InputStream wrappedStream,
             final InputStreamFactory inputStreamFactory) {
-        this.wrappedStream = wrappedStream;
+        super(wrappedStream);
         this.inputStreamFactory = inputStreamFactory;
     }
 
-    private void initWrapper() throws IOException {
+    private InputStream initWrapper() throws IOException {
         if (wrapperStream == null) {
-            wrapperStream = inputStreamFactory.create(wrappedStream);
+            wrapperStream = inputStreamFactory.create(in);
         }
+        return wrapperStream;
     }
 
     @Override
     public int read() throws IOException {
-        initWrapper();
-        return wrapperStream.read();
+        return initWrapper().read();
     }
 
     @Override
     public int read(final byte[] b) throws IOException {
-        initWrapper();
-        return wrapperStream.read(b);
+        return initWrapper().read(b);
     }
 
     @Override
     public int read(final byte[] b, final int off, final int len) throws IOException {
-        initWrapper();
-        return wrapperStream.read(b, off, len);
+        return initWrapper().read(b, off, len);
     }
 
     @Override
     public long skip(final long n) throws IOException {
-        initWrapper();
-        return wrapperStream.skip(n);
+        return initWrapper().skip(n);
     }
 
     @Override
@@ -83,19 +83,29 @@ class LazyDecompressingInputStream extends InputStream {
 
     @Override
     public int available() throws IOException {
-        initWrapper();
-        return wrapperStream.available();
+        return initWrapper().available();
     }
 
     @Override
     public void close() throws IOException {
         try {
-            if (wrapperStream != null) {
-                wrapperStream.close();
-            }
+            Closer.close(wrapperStream);
         } finally {
-            wrappedStream.close();
+            super.close();
         }
     }
 
+    @Override
+    public void mark(final int readlimit) {
+        try {
+            initWrapper().mark(readlimit);
+        } catch (final IOException e) {
+            throw new UncheckedIOException(e);
+        }
+    }
+
+    @Override
+    public void reset() throws IOException {
+        initWrapper().reset();
+    }
 }

httpclient5/src/test/java/org/apache/hc/client5/http/entity/TestDecompressingEntity.java

@@ -76,6 +76,22 @@ class TestDecompressingEntity {
         EntityUtils.consume(entity);
     }
 
+    @Test
+    void testStreamingMarking() throws Exception {
+        final CRC32 crc32 = new CRC32();
+        final ByteArrayInputStream in = new ByteArrayInputStream("1234567890".getBytes(StandardCharsets.US_ASCII));
+        final InputStreamEntity wrapped = new InputStreamEntity(in, -1, ContentType.DEFAULT_TEXT);
+        final ChecksumEntity entity = new ChecksumEntity(wrapped, crc32);
+        final InputStream in1 = entity.getContent();
+        Assertions.assertEquals('1', in1.read());
+        Assertions.assertEquals('2', in1.read());
+        in1.mark(1);
+        Assertions.assertEquals('3', in1.read());
+        in1.reset();
+        Assertions.assertEquals('3', in1.read());
+        EntityUtils.consume(entity);
+    }
+
     @Test
     void testWriteToStream() throws Exception {
         final CRC32 crc32 = new CRC32();
@@ -101,3 +117,4 @@ class TestDecompressingEntity {
     }
 
 }
+