Parse central directory part of ZIP extra fields. PR 46637

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@749610 13f79535-47bb-0310-9956-ffa450edef68

src/main/org/apache/tools/zip/CentralDirectoryParsingZipExtraField.java

@@ -0,0 +1,40 @@
+/*
+ *  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 org.apache.tools.zip;
+
+import java.util.zip.ZipException;
+
+/**
+ * {@link ZipExtraField ZipExtraField} that knows how to parse central
+ * directory data.
+ *
+ * @since Ant 1.8.0
+ */
+public interface CentralDirectoryParsingZipExtraField extends ZipExtraField {
+    /**
+     * Populate data from this array as if it was in central directory data.
+     * @param data an array of bytes
+     * @param offset the start offset
+     * @param length the number of bytes in the array from offset
+     *
+     * @throws ZipException on error
+     */
+    void parseFromCentralDirectoryData(byte[] data, int offset, int length)
+        throws ZipException;
+}

src/main/org/apache/tools/zip/ExtraFieldUtils.java

@@ -92,13 +92,27 @@ public class ExtraFieldUtils {
 
     /**
      * Split the array into ExtraFields and populate them with the
-     * give data.
+     * given data as local file data.
+     * @param data an array of bytes as it appears in local file data
+     * @return an array of ExtraFields
+     * @throws ZipException on error
+     */
+    public static ZipExtraField[] parse(byte[] data) throws ZipException {
+        return parse(data, true);
+    }
+
+    /**
+     * Split the array into ExtraFields and populate them with the
+     * given data.
      * @param data an array of bytes
+     * @param local whether data originates from the local file data
+     * or the central directory
      * @return an array of ExtraFields
      * @since 1.1
      * @throws ZipException on error
      */
-    public static ZipExtraField[] parse(byte[] data) throws ZipException {
+    public static ZipExtraField[] parse(byte[] data, boolean local)
+        throws ZipException {
         List v = new ArrayList();
         int start = 0;
         while (start <= data.length - WORD) {
@@ -110,7 +124,14 @@ public class ExtraFieldUtils {
             }
             try {
                 ZipExtraField ze = createExtraField(headerId);
-                ze.parseFromLocalFileData(data, start + WORD, length);
+                if (local
+                    || !(ze instanceof CentralDirectoryParsingZipExtraField)) {
+                    ze.parseFromLocalFileData(data, start + WORD, length);
+                } else {
+                    ((CentralDirectoryParsingZipExtraField) ze)
+                        .parseFromCentralDirectoryData(data, start + WORD,
+                                                       length);
+                }
                 v.add(ze);
             } catch (InstantiationException ie) {
                 throw new ZipException(ie.getMessage());

src/main/org/apache/tools/zip/UnrecognizedExtraField.java

@@ -26,7 +26,8 @@ package org.apache.tools.zip;
  * identical - unless told the opposite.</p>
  *
  */
-public class UnrecognizedExtraField implements ZipExtraField {
+public class UnrecognizedExtraField
+    implements CentralDirectoryParsingZipExtraField {
 
     /**
      * The Header-ID.
@@ -135,6 +136,22 @@ public class UnrecognizedExtraField implements ZipExtraField {
         setLocalFileDataData(tmp);
     }
 
+    /**
+     * @param data the array of bytes.
+     * @param offset the source location in the data array.
+     * @param length the number of bytes to use in the data array.
+     * @see ZipExtraField#parseFromCentralDirectoryData(byte[], int, int)
+     */
+    public void parseFromCentralDirectoryData(byte[] data, int offset,
+                                              int length) {
+        byte[] tmp = new byte[length];
+        System.arraycopy(data, offset, tmp, 0, length);
+        setCentralDirectoryData(tmp);
+        if (localData == null) {
+            setLocalFileDataData(tmp);
+        }
+    }
+
     private static byte[] copy(byte[] from) {
         if (from != null) {
             byte[] to = new byte[from.length];

src/main/org/apache/tools/zip/ZipEntry.java

@@ -284,7 +284,8 @@ public class ZipEntry extends java.util.zip.ZipEntry implements Cloneable {
      */
     public void setExtra(byte[] extra) throws RuntimeException {
         try {
-            setExtraFields(ExtraFieldUtils.parse(extra));
+            ZipExtraField[] local = ExtraFieldUtils.parse(extra, true);
+            mergeExtraFields(local, true);
         } catch (Exception e) {
             throw new RuntimeException(e.getMessage(), e);
         }
@@ -302,6 +303,18 @@ public class ZipEntry extends java.util.zip.ZipEntry implements Cloneable {
         super.setExtra(ExtraFieldUtils.mergeLocalFileDataData(getExtraFields()));
     }
 
+    /**
+     * Sets the central directory part of extra fields.
+     */
+    public void setCentralDirectoryExtra(byte[] b) {
+        try {
+            ZipExtraField[] central = ExtraFieldUtils.parse(b, false);
+            mergeExtraFields(central, false);
+        } catch (Exception e) {
+            throw new RuntimeException(e.getMessage(), e);
+        }
+    }
+
     /**
      * Retrieves the extra data for the local file data.
      * @return the extra data for local file
@@ -386,4 +399,37 @@ public class ZipEntry extends java.util.zip.ZipEntry implements Cloneable {
         return (this == o);
     }
 
+    /**
+     * If there are no extra fields, use the given fields as new extra
+     * data - otherwise merge the fields assuming the existing fields
+     * and the new fields stem from different locations inside the
+     * archive.
+     * @param f the extra fields to merge
+     * @param local whether the new fields originate from local data
+     */
+    private void mergeExtraFields(ZipExtraField[] f, boolean local)
+        throws ZipException {
+        if (extraFields == null) {
+            setExtraFields(f);
+        } else {
+            for (int i = 0; i < f.length; i++) {
+                ZipExtraField existing = getExtraField(f[i].getHeaderId());
+                if (existing == null) {
+                    addExtraField(f[i]);
+                } else {
+                    if (local
+                        || !(existing
+                             instanceof CentralDirectoryParsingZipExtraField)) {
+                        byte[] b = f[i].getLocalFileDataData();
+                        existing.parseFromLocalFileData(b, 0, b.length);
+                    } else {
+                        byte[] b = f[i].getCentralDirectoryData();
+                        ((CentralDirectoryParsingZipExtraField) existing)
+                            .parseFromCentralDirectoryData(b, 0, b.length);
+                    }
+                }
+            }
+            setExtra();
+        }
+    }
 }

src/main/org/apache/tools/zip/ZipFile.java

@@ -389,15 +389,9 @@ public class ZipFile {
 
             nameMap.put(ze.getName(), ze);
 
-            int lenToSkip = extraLen;
-            while (lenToSkip > 0) {
-                int skipped = archive.skipBytes(lenToSkip);
-                if (skipped <= 0) {
-                    throw new RuntimeException("failed to skip extra data in"
-                                               + " central directory");
-                }
-                lenToSkip -= skipped;
-            }            
+            byte[] cdExtraData = new byte[extraLen];
+            archive.readFully(cdExtraData);
+            ze.setCentralDirectoryExtra(cdExtraData);
 
             byte[] comment = new byte[commentLen];
             archive.readFully(comment);

src/tests/junit/org/apache/tools/zip/ZipEntryTest.java

@@ -32,8 +32,6 @@ public class ZipEntryTest extends TestCase {
 
     /**
      * test handling of extra fields
-     *
-     * @since 1.1
      */
     public void testExtraFields() {
         AsiExtraField a = new AsiExtraField();
@@ -85,10 +83,52 @@ public class ZipEntryTest extends TestCase {
         }
     }
 
+    /**
+     * test handling of extra fields via central directory
+     */
+    public void testExtraFieldMerging() {
+        AsiExtraField a = new AsiExtraField();
+        a.setDirectory(true);
+        a.setMode(0755);
+        UnrecognizedExtraField u = new UnrecognizedExtraField();
+        u.setHeaderId(new ZipShort(1));
+        u.setLocalFileDataData(new byte[0]);
+
+        ZipEntry ze = new ZipEntry("test/");
+        ze.setExtraFields(new ZipExtraField[] {a, u});
+
+        // merge
+        // Header-ID 1 + length 1 + one byte of data
+        ze.setCentralDirectoryExtra(new byte[] {1, 0, 1, 0, 127});
+
+        ZipExtraField[] result = ze.getExtraFields();
+        assertEquals("first pass", 2, result.length);
+        assertSame(a, result[0]);
+        assertEquals(new ZipShort(1), result[1].getHeaderId());
+        assertEquals(new ZipShort(0), result[1].getLocalFileDataLength());
+        assertEquals(new ZipShort(1), result[1].getCentralDirectoryLength());
+
+        // add new
+        // Header-ID 2 + length 0
+        ze.setCentralDirectoryExtra(new byte[] {2, 0, 0, 0});
+
+        result = ze.getExtraFields();
+        assertEquals("second pass", 3, result.length);
+
+        // merge
+        // Header-ID 2 + length 1 + one byte of data
+        ze.setExtra(new byte[] {2, 0, 1, 0, 127});
+
+        result = ze.getExtraFields();
+        assertEquals("third pass", 3, result.length);
+        assertSame(a, result[0]);
+        assertEquals(new ZipShort(2), result[2].getHeaderId());
+        assertEquals(new ZipShort(1), result[2].getLocalFileDataLength());
+        assertEquals(new ZipShort(0), result[2].getCentralDirectoryLength());
+    }
+
     /**
      * test handling of extra fields
-     *
-     * @since 1.1
      */
     public void testAddAsFirstExtraField() {
         AsiExtraField a = new AsiExtraField();