Merge remote-tracking branch 'ArneBab/commons-compress-workaround' in…

…to release-1481-preparation

src/freenet/client/ArchiveManager.java

@@ -36,7 +36,7 @@
 import freenet.support.compress.Compressor.COMPRESSOR_TYPE;
 import freenet.support.io.BucketTools;
 import freenet.support.io.Closer;
-
+import freenet.support.io.SkipShieldingInputStream;
 import net.contrapunctus.lzma.LzmaInputStream;
 
 /**
@@ -348,16 +348,14 @@ public void run() {
 				wrapper = null;
 			}
 
-			if(ARCHIVE_TYPE.ZIP == archiveType)
+			if(ARCHIVE_TYPE.ZIP == archiveType) {
 				handleZIPArchive(ctx, key, is, element, callback, gotElement, throwAtExit, context);
-			else if(ARCHIVE_TYPE.TAR == archiveType) {
-                                // COMPRESS-449 workaround, see https://freenet.mantishub.io/view.php?id=6921
-                                byte[] buf = new byte[(int) archiveSize];
-                                is.read(buf);
-				handleTARArchive(ctx, key, new ByteArrayInputStream(buf), element, callback, gotElement, throwAtExit, context);
-                        }
-		else
+			} else if(ARCHIVE_TYPE.TAR == archiveType) {
+				 // COMPRESS-449 workaround, see https://freenet.mantishub.io/view.php?id=6921
+				handleTARArchive(ctx, key, new SkipShieldingInputStream(is), element, callback, gotElement, throwAtExit, context);
+			} else {
 				throw new ArchiveFailureException("Unknown or unsupported archive algorithm " + archiveType);
+			}
 			if(wrapper != null) {
 				Exception e = wrapper.get();
 				if(e != null) throw new ArchiveFailureException("An exception occured decompressing: "+e.getMessage(), e);

src/freenet/support/io/SkipShieldingInputStream.java

@@ -0,0 +1,51 @@
+/*
+ *  Licensed to the Apache Software Foundation (ASF) under one or more
+ *  contributor license agreements.  See the NOTICE file distributed with
+ *  this work for additional information regarding copyright ownership.
+ *  The ASF licenses this file to You under the Apache License, Version 2.0
+ *  (the "License"); you may not use this file except in compliance with
+ *  the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ */
+package freenet.support.io;
+
+import java.io.FilterInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * A wrapper that overwrites {@link #skip} and delegates to {@link #read} instead.
+ *
+ * <p>Some implementations of {@link InputStream} implement {@link
+ * InputStream#skip} in a way that throws an expecption if the stream
+ * is not seekable - {@link System#in System.in} is known to behave
+ * that way. For such a stream it is impossible to invoke skip at all
+ * and you have to read from the stream (and discard the data read)
+ * instead. Skipping is potentially much faster than reading so we do
+ * want to invoke {@code skip} when possible. We provide this class so
+ * you can wrap your own {@link InputStream} in it if you encounter
+ * problems with {@code skip} throwing an excpetion.</p>
+ *
+ * @since 1.17
+ */
+public class SkipShieldingInputStream extends FilterInputStream {
+    private static final int SKIP_BUFFER_SIZE = 8192;
+    // we can use a shared buffer as the content is discarded anyway
+    private static final byte[] SKIP_BUFFER = new byte[SKIP_BUFFER_SIZE];
+    public SkipShieldingInputStream(InputStream in) {
+        super(in);
+    }
+
+    @Override
+    public long skip(long n) throws IOException {
+        return n < 0 ? 0 : read(SKIP_BUFFER, 0, (int) Math.min(n, SKIP_BUFFER_SIZE));
+    }
+}