Fix for bug 45698 - allow LinkTable to read EXTERNSHEET records

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@689704 13f79535-47bb-0310-9956-ffa450edef68

src/documentation/content/xdocs/changes.xml

@@ -37,6 +37,7 @@
 
 		<!-- Don't forget to update status.xml too! -->
         <release version="3.1.1-alpha1" date="2008-??-??">
+           <action dev="POI-DEVELOPERS" type="fix">45698 - Fix LinkTable to tolerate multiple EXTERNSHEET records</action>
            <action dev="POI-DEVELOPERS" type="fix">45682 - Fix for cloning of CFRecordsAggregate</action>
            <action dev="POI-DEVELOPERS" type="add">Initial support for evaluating external add-in functions like YEARFRAC</action>
            <action dev="POI-DEVELOPERS" type="fix">45672 - Fix for MissingRecordAwareHSSFListener to prevent multiple LastCellOfRowDummyRecords when shared formulas are present</action>

src/documentation/content/xdocs/status.xml

@@ -34,6 +34,7 @@
 	<!-- Don't forget to update changes.xml too! -->
     <changes>
         <release version="3.1.1-alpha1" date="2008-??-??">
+           <action dev="POI-DEVELOPERS" type="fix">45698 - Fix LinkTable to tolerate multiple EXTERNSHEET records</action>
            <action dev="POI-DEVELOPERS" type="fix">45682 - Fix for cloning of CFRecordsAggregate</action>
            <action dev="POI-DEVELOPERS" type="add">Initial support for evaluating external add-in functions like YEARFRAC</action>
            <action dev="POI-DEVELOPERS" type="fix">45672 - Fix for MissingRecordAwareHSSFListener to prevent multiple LastCellOfRowDummyRecords when shared formulas are present</action>

src/java/org/apache/poi/hssf/model/LinkTable.java

@@ -159,8 +159,7 @@ final class LinkTable {
 		
 		if (_externalBookBlocks.length > 0) {
 			// If any ExternalBookBlock present, there is always 1 of ExternSheetRecord
-			Record next = rs.getNext();
-			_externSheetRecord = (ExternSheetRecord) next;
+			_externSheetRecord = readExtSheetRecord(rs);
 		} else {
 			_externSheetRecord = null;
 		}
@@ -176,6 +175,28 @@ final class LinkTable {
 		_workbookRecordList.getRecords().addAll(inputList.subList(startIndex, startIndex + _recordCount));
 	}
 
+	private static ExternSheetRecord readExtSheetRecord(RecordStream rs) {
+		List temp = new ArrayList(2);
+		while(rs.peekNextClass() == ExternSheetRecord.class) {
+			temp.add(rs.getNext());
+		}
+		
+		int nItems = temp.size();
+		if (nItems < 1) {
+			throw new RuntimeException("Expected an EXTERNSHEET record but got (" 
+					+ rs.peekNextClass().getName() + ")");
+		}
+		if (nItems == 1) {
+			// this is the normal case. There should be just one ExternSheetRecord
+			return (ExternSheetRecord) temp.get(0);
+		}
+		// Some apps generate multiple ExternSheetRecords (see bug 45698).
+		// It seems like the best thing to do might be to combine these into one
+		ExternSheetRecord[] esrs = new ExternSheetRecord[nItems];
+		temp.toArray(esrs);
+		return ExternSheetRecord.combine(esrs);
+	}
+
 	public LinkTable(short numberOfSheets, WorkbookRecordList workbookRecordList) {
 		_workbookRecordList = workbookRecordList;
 		_definedNames = new ArrayList();

src/java/org/apache/poi/hssf/record/ExternSheetRecord.java

@@ -260,4 +260,16 @@ public class ExternSheetRecord extends Record {
 		}
 		return -1;
 	}
+
+	public static ExternSheetRecord combine(ExternSheetRecord[] esrs) {
+		ExternSheetRecord result = new ExternSheetRecord();
+		for (int i = 0; i < esrs.length; i++) {
+			ExternSheetRecord esr = esrs[i];
+			int nRefs = esr.getNumOfREFRecords();
+			for (int j=0; j<nRefs; j++) {
+				result.addREFRecord(esr.getRef(j));
+			}
+		}
+		return result;
+	}
 }

src/testcases/org/apache/poi/hssf/usermodel/TestLinkTable.java

@@ -41,4 +41,19 @@ public final class TestLinkTable extends TestCase {
 		
 		assertEquals("ipcSummenproduktIntern($C5,N$2,$A$9,N$1)", formula);
 	}
+	
+	public void testMultipleExternSheetRecords_bug45698() {
+		HSSFWorkbook wb;
+
+		try {
+			wb = HSSFTestDataSamples.openSampleWorkbook("ex45698-22488.xls");
+		} catch (RuntimeException e) {
+			if ("Extern sheet is part of LinkTable".equals(e.getMessage())) {
+				throw new AssertionFailedError("Identified bug 45698");
+			}
+			throw e;
+		}
+		// some other sanity checks
+		assertEquals(7, wb.getNumberOfSheets());
+	}
 }