If an empty stream or file is given to WorkbookFactory.create, give a more informative exception - EmptyFileException

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1677562 13f79535-47bb-0310-9956-ffa450edef68

2 files changed, 34 insertions, 1 deletions

diff --git a/src/ooxml/java/org/apache/poi/ss/usermodel/WorkbookFactory.java b/src/ooxml/java/org/apache/poi/ss/usermodel/WorkbookFactory.java
index bdf37eafca..80d9b76d4f 100644
--- a/src/ooxml/java/org/apache/poi/ss/usermodel/WorkbookFactory.java
+++ b/src/ooxml/java/org/apache/poi/ss/usermodel/WorkbookFactory.java
@@ -23,6 +23,7 @@ import java.io.InputStream;
 import java.io.PushbackInputStream;
 import java.security.GeneralSecurityException;
 
+import org.apache.poi.EmptyFileException;
 import org.apache.poi.EncryptedDocumentException;
 import org.apache.poi.POIXMLDocument;
 import org.apache.poi.hssf.record.crypto.Biff8EncryptionKey;
@@ -35,6 +36,7 @@ import org.apache.poi.poifs.filesystem.DirectoryNode;
 import org.apache.poi.poifs.filesystem.NPOIFSFileSystem;
 import org.apache.poi.poifs.filesystem.OfficeXmlFileException;
 import org.apache.poi.poifs.filesystem.POIFSFileSystem;
+import org.apache.poi.util.IOUtils;
 import org.apache.poi.xssf.usermodel.XSSFWorkbook;
 
 /**
@@ -153,14 +155,19 @@ public class WorkbookFactory {
      *  from an InputStream requires more memory than loading
      *  from a File, so prefer {@link #create(File)} where possible.
      * @throws EncryptedDocumentException If the wrong password is given for a protected file
+     * @throws EmptyFileException If an empty stream is given
      */
     public static Workbook create(InputStream inp, String password) throws IOException, InvalidFormatException, EncryptedDocumentException {
         // If clearly doesn't do mark/reset, wrap up
         if (! inp.markSupported()) {
             inp = new PushbackInputStream(inp, 8);
         }
+        
+        // Ensure that there is at least some data there
+        byte[] header8 = IOUtils.peekFirst8Bytes(inp);
 
-        if (POIFSFileSystem.hasPOIFSHeader(inp)) {
+        // Try to create
+        if (POIFSFileSystem.hasPOIFSHeader(header8)) {
             NPOIFSFileSystem fs = new NPOIFSFileSystem(inp);
             return create(fs, password);
         }
@@ -187,6 +194,7 @@ public class WorkbookFactory {
      * <p>Note that in order to properly release resources the 
      *  Workbook should be closed after use.
      * @throws EncryptedDocumentException If the wrong password is given for a protected file
+     * @throws EmptyFileException If an empty stream is given
      */
     public static Workbook create(File file, String password) throws IOException, InvalidFormatException, EncryptedDocumentException {
         if (! file.exists()) {
diff --git a/src/ooxml/testcases/org/apache/poi/ss/TestWorkbookFactory.java b/src/ooxml/testcases/org/apache/poi/ss/TestWorkbookFactory.java
index 582c8c3646..27d6d9ec1a 100644
--- a/src/ooxml/testcases/org/apache/poi/ss/TestWorkbookFactory.java
+++ b/src/ooxml/testcases/org/apache/poi/ss/TestWorkbookFactory.java
@@ -17,14 +17,18 @@
 
 package org.apache.poi.ss;
 
+import java.io.ByteArrayInputStream;
+import java.io.File;
 import java.io.InputStream;
 
+import org.apache.poi.EmptyFileException;
 import org.apache.poi.EncryptedDocumentException;
 import org.apache.poi.hssf.usermodel.HSSFWorkbook;
 import org.apache.poi.hssf.HSSFTestDataSamples;
 import org.apache.poi.poifs.filesystem.POIFSFileSystem;
 import org.apache.poi.ss.usermodel.Workbook;
 import org.apache.poi.ss.usermodel.WorkbookFactory;
+import org.apache.poi.util.TempFile;
 import org.apache.poi.xssf.usermodel.XSSFWorkbook;
 import org.apache.poi.openxml4j.opc.OPCPackage;
 
@@ -254,4 +258,25 @@ public final class TestWorkbookFactory extends TestCase {
             fail("Shouldn't be able to open with the wrong password");
         } catch (EncryptedDocumentException e) {}
     }
+    
+    /**
+     * Check that a helpful exception is given on an empty file / stream
+     */
+    public void testEmptyFile() throws Exception {
+        InputStream emptyStream = new ByteArrayInputStream(new byte[0]);
+        File emptyFile = TempFile.createTempFile("empty", ".poi");
+        
+        try {
+            WorkbookFactory.create(emptyStream);
+            fail("Shouldn't be able to create for an empty stream");
+        } catch (EmptyFileException e) {
+        }
+        
+        try {
+            WorkbookFactory.create(emptyFile);
+            fail("Shouldn't be able to create for an empty file");
+        } catch (EmptyFileException e) {
+        }
+        emptyFile.delete();
+    }
 }