Add methods to check to see if a given InputStream has a OOXML file header, or a OLE2 file header, so that a future factory method could figure out which class to instantiate for a given InputStraeam

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@612438 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/poi/poifs/common/POIFSConstants.java

@@ -31,4 +31,7 @@ public interface POIFSConstants
     public static final int END_OF_CHAIN   = -2;
     public static final int PROPERTY_SIZE  = 0x0080;
     public static final int UNUSED_BLOCK   = -1;
+    
+    public static final byte[] OOXML_FILE_HEADER = 
+    	new byte[] { 0x50, 0x4b, 0x03, 0x04 };
 }   // end public interface POIFSConstants;

src/java/org/apache/poi/poifs/filesystem/POIFSFileSystem.java

@@ -34,6 +34,7 @@ import org.apache.poi.poifs.storage.BlockAllocationTableReader;
 import org.apache.poi.poifs.storage.BlockAllocationTableWriter;
 import org.apache.poi.poifs.storage.BlockList;
 import org.apache.poi.poifs.storage.BlockWritable;
+import org.apache.poi.poifs.storage.HeaderBlockConstants;
 import org.apache.poi.poifs.storage.HeaderBlockReader;
 import org.apache.poi.poifs.storage.HeaderBlockWriter;
 import org.apache.poi.poifs.storage.RawDataBlock;
@@ -41,6 +42,9 @@ import org.apache.poi.poifs.storage.RawDataBlockList;
 import org.apache.poi.poifs.storage.SmallBlockTableReader;
 import org.apache.poi.poifs.storage.SmallBlockTableWriter;
 import org.apache.poi.poifs.storage.SmallDocumentBlock;
+import org.apache.poi.util.IOUtils;
+import org.apache.poi.util.LongField;
+import org.apache.xmlbeans.impl.common.IOUtil;
 
 /**
  * This is the main class of the POIFS system; it manages the entire
@@ -107,6 +111,35 @@ public class POIFSFileSystem
                         .getChildren(), null);
     }
     
+    /**
+     * Checks that the supplied InputStream (which MUST
+     *  support mark and reset, or be a PushbackInputStream) 
+     *  has a POIFS (OLE2) header at the start of it.
+     * If your InputStream does not support mark / reset,
+     *  then wrap it in a PushBackInputStream, then be
+     *  sure to always use that, and not the original!
+     * @param inp An InputStream which supports either mark/reset, or is a PushbackInputStream 
+     */
+    public static boolean hasPOIFSHeader(InputStream inp) throws IOException {
+    	// We want to peek at the first 8 bytes 
+    	inp.mark(8);
+
+    	byte[] header = new byte[8];
+    	IOUtils.readFully(inp, header);
+        LongField signature = new LongField(HeaderBlockConstants._signature_offset, header);
+
+        // Wind back those 8 bytes
+        if(inp instanceof PushbackInputStream) {
+        	PushbackInputStream pin = (PushbackInputStream)inp;
+        	pin.unread(header);
+        } else {
+        	inp.reset();
+        }
+    	
+    	// Did it match the signature?
+    	return (signature.get() == HeaderBlockConstants._signature);
+    }
+
     /**
      * Create a new document to be added to the root directory
      *

src/java/org/apache/poi/poifs/storage/HeaderBlockReader.java

@@ -91,8 +91,11 @@ public class HeaderBlockReader
         if (signature.get() != _signature)
         {
 			// Is it one of the usual suspects?
-			if(_data[0] == 0x50 && _data[1] == 0x4b && _data[2] == 0x03 &&
+        	byte[] OOXML_FILE_HEADER = POIFSConstants.OOXML_FILE_HEADER;
-					_data[3] == 0x04) {
+			if(_data[0] == OOXML_FILE_HEADER[0] && 
+					_data[1] == OOXML_FILE_HEADER[1] && 
+					_data[2] == OOXML_FILE_HEADER[2] &&
+					_data[3] == OOXML_FILE_HEADER[3]) {
 				throw new OfficeXmlFileException("The supplied data appears to be in the Office 2007+ XML. POI only supports OLE2 Office documents");
 			}
 

src/scratchpad/ooxml-src/org/apache/poi/hxf/HXFDocument.java

@@ -18,9 +18,15 @@ package org.apache.poi.hxf;
 
 import java.io.File;
 import java.io.IOException;
+import java.io.InputStream;
+import java.io.PushbackInputStream;
 import java.util.ArrayList;
 
 import org.apache.poi.POIXMLDocument;
+import org.apache.poi.poifs.common.POIFSConstants;
+import org.apache.poi.poifs.storage.HeaderBlockConstants;
+import org.apache.poi.util.IOUtils;
+import org.apache.poi.util.LongField;
 import org.apache.xmlbeans.XmlException;
 import org.dom4j.Document;
 import org.dom4j.DocumentException;
@@ -87,6 +93,39 @@ public abstract class HXFDocument {
 		}
 	}
 	
+    /**
+     * Checks that the supplied InputStream (which MUST
+     *  support mark and reset, or be a PushbackInputStream) 
+     *  has a OOXML (zip) header at the start of it.
+     * If your InputStream does not support mark / reset,
+     *  then wrap it in a PushBackInputStream, then be
+     *  sure to always use that, and not the original!
+     * @param inp An InputStream which supports either mark/reset, or is a PushbackInputStream 
+     */
+    public static boolean hasOOXMLHeader(InputStream inp) throws IOException {
+    	// We want to peek at the first 4 bytes 
+    	inp.mark(4);
+
+    	byte[] header = new byte[4];
+    	IOUtils.readFully(inp, header);
+
+        // Wind back those 4 bytes
+        if(inp instanceof PushbackInputStream) {
+        	PushbackInputStream pin = (PushbackInputStream)inp;
+        	pin.unread(header);
+        } else {
+        	inp.reset();
+        }
+    	
+    	// Did it match the ooxml zip signature?
+        return (
+        	header[0] == POIFSConstants.OOXML_FILE_HEADER[0] && 
+        	header[1] == POIFSConstants.OOXML_FILE_HEADER[1] && 
+        	header[2] == POIFSConstants.OOXML_FILE_HEADER[2] && 
+        	header[3] == POIFSConstants.OOXML_FILE_HEADER[3]
+        );        	                                            
+    }
+    
 	/**
 	 * Fetches the (single) PackagePart with the supplied
 	 *  content type.

src/scratchpad/ooxml-testcases/org/apache/poi/hxf/TestDetectAsOOXML.java

@@ -0,0 +1,65 @@
+
+/* ====================================================================
+   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.poi.hxf;
+
+import junit.framework.TestCase;
+import java.io.*;
+
+/**
+ * Class to test that HXF correctly detects OOXML
+ *  documents
+ */
+public class TestDetectAsOOXML extends TestCase
+{
+	public String dirname;
+
+	public void setUp() {
+		dirname = System.getProperty("HSSF.testdata.path");
+	}
+
+	public void testOpensProperly() throws Exception
+	{
+		File f = new File(dirname + "/sample.xlsx");
+
+		HXFDocument.openPackage(f);
+	}
+	
+	public void testDetectAsPOIFS() throws Exception {
+		InputStream in;
+		
+		// ooxml file is
+		in = new PushbackInputStream(
+				new FileInputStream(dirname + "/SampleSS.xlsx"), 10
+		);
+		assertTrue(HXFDocument.hasOOXMLHeader(in));
+		
+		// xls file isn't
+		in = new PushbackInputStream(
+				new FileInputStream(dirname + "/SampleSS.xls"), 10
+		);
+		assertFalse(HXFDocument.hasOOXMLHeader(in));
+		
+		// text file isn't
+		in = new PushbackInputStream(
+				new FileInputStream(dirname + "/SampleSS.txt"), 10
+		);
+		assertFalse(HXFDocument.hasOOXMLHeader(in));
+	}
+}

src/testcases/org/apache/poi/poifs/filesystem/TestOffice2007XMLException.java

@@ -47,4 +47,26 @@ public class TestOffice2007XMLException extends TestCase
 			// Good
 		}
 	}
+	
+	public void testDetectAsPOIFS() throws IOException {
+		InputStream in;
+		
+		// ooxml file isn't
+		in = new PushbackInputStream(
+				new FileInputStream(dirname + "/SampleSS.xlsx"), 10
+		);
+		assertFalse(POIFSFileSystem.hasPOIFSHeader(in));
+		
+		// xls file is
+		in = new PushbackInputStream(
+				new FileInputStream(dirname + "/SampleSS.xls"), 10
+		);
+		assertTrue(POIFSFileSystem.hasPOIFSHeader(in));
+		
+		// text file isn't
+		in = new PushbackInputStream(
+				new FileInputStream(dirname + "/SampleSS.txt"), 10
+		);
+		assertFalse(POIFSFileSystem.hasPOIFSHeader(in));
+	}
 }