#66157

4 files changed, 96 insertions, 19 deletions

diff --git a/org.eclipse.jface.text/src/org/eclipse/jface/text/TextViewer.java b/org.eclipse.jface.text/src/org/eclipse/jface/text/TextViewer.java
index 70b2844c4c4..a3c40a26011 100644
--- a/org.eclipse.jface.text/src/org/eclipse/jface/text/TextViewer.java
+++ b/org.eclipse.jface.text/src/org/eclipse/jface/text/TextViewer.java
@@ -1876,7 +1876,9 @@ public class TextViewer extends Viewer implements
 		
 		if (fTextWidget != null) {
 			Point p= fTextWidget.getSelectionRange();
-			return widgetSelection2ModelSelection(p);
+			p= widgetSelection2ModelSelection(p);
+			if (p != null)
+				return p;
 		}
 		
 		return new Point(-1, -1);
diff --git a/org.eclipse.text.tests/projection/org/eclipse/text/tests/ProjectionDocumentTest.java b/org.eclipse.text.tests/projection/org/eclipse/text/tests/ProjectionDocumentTest.java
index 19fb7a047a5..3944f8f93ff 100644
--- a/org.eclipse.text.tests/projection/org/eclipse/text/tests/ProjectionDocumentTest.java
+++ b/org.eclipse.text.tests/projection/org/eclipse/text/tests/ProjectionDocumentTest.java
@@ -202,7 +202,7 @@ public class ProjectionDocumentTest extends TestCase {
 
 		Position previous= null;
 		for (int i= 0; i < segmentation.length; i++) {
-			assertFalse(segmentation[i].getLength() == 0);
+			assertFalse(segmentation.length > 1 && segmentation[i].getLength() == 0);
 			if (previous != null)
 				assertTrue(previous.getOffset() + previous.getLength() == segmentation[i].getOffset());
 			previous= segmentation[i];
@@ -223,7 +223,7 @@ public class ProjectionDocumentTest extends TestCase {
 			Fragment fragment= (Fragment) fragmention[i];
 			assertTrue(fragment == segment.fragment);
 			assertTrue(segment == fragment.segment);
-			assertFalse(fragment.getLength() == 0);
+			assertFalse(segmentation.length > 1 && fragment.getLength() == 0);
 			assertTrue(fragment.length == segment.length);
 			if (previous != null)
 				assertFalse(previous.getOffset() + previous.getLength() == fragment.getOffset());
@@ -1844,4 +1844,51 @@ public class ProjectionDocumentTest extends TestCase {
 		};
 		assertFragmentation(expected);
 	}
+		
+	public void test28_a() {
+		// delete slave content and check fragmentation, need to keep a single fragment as anchor
+		createProjectionB();
+		try {
+			fSlaveDocument.replace(0, fSlaveDocument.getLength(), null);
+		} catch (BadLocationException e) {
+			assertTrue(false);
+		}
+		assertSlaveContents("");
+		StringBuffer buffer= new StringBuffer(getOriginalMasterContents());
+		buffer.delete(20, 160);
+		assertMasterContents(buffer.toString());
+		
+		Position[] expected= new Position[] {
+			new Position(20, 0)
+		};
+		assertFragmentation(expected);
+	}
+	
+	public void test28_b() {
+		// test step wise version of the complete replace
+		// delete whole content of slave, followed by inserting text
+		
+		createProjectionB();
+		try {
+			fSlaveDocument.replace(0, fSlaveDocument.getLength(), null);
+		} catch (BadLocationException e) {
+			assertTrue(false);
+		}
+		
+		try {
+			fSlaveDocument.replace(0, 0, "~~~~~");
+		} catch (BadLocationException e) {
+			assertTrue(false);
+		}
+		
+		Position[] expected= new Position[] {
+			new Position(20, 5)
+		};
+		assertFragmentation(expected);
+		
+		assertSlaveContents("~~~~~");
+		StringBuffer buffer= new StringBuffer(getOriginalMasterContents());
+		buffer.replace(20, 160, "~~~~~");
+		assertMasterContents(buffer.toString());		
+	}
 }
diff --git a/org.eclipse.text/projection/org/eclipse/jface/text/projection/ProjectionDocument.java b/org.eclipse.text/projection/org/eclipse/jface/text/projection/ProjectionDocument.java
index 2a38c4d17a4..c69e66ed508 100644
--- a/org.eclipse.text/projection/org/eclipse/jface/text/projection/ProjectionDocument.java
+++ b/org.eclipse.text/projection/org/eclipse/jface/text/projection/ProjectionDocument.java
@@ -648,15 +648,17 @@ public class ProjectionDocument extends AbstractDocument {
 		
 		} else if (fMapping.getImageLength() == 0 && masterEvent.getLength() == 0) {
 			
-			// there is no segment in this projection document, thus one must be created
-			// need to bypass the usual infrastructure as the new segment/fragment would be of length 0 and thus the segmentation be not well formed
-			
-			try {
-				Fragment fragment= new Fragment(0, 0);
-				fMasterDocument.addPosition(fFragmentsCategory, fragment);
-				createSegmentFor(fragment, 0);
-			} catch (BadPositionCategoryException x) {
-				internalError();
+			Position[] fragments= getFragments();
+			if (fragments.length == 0) {
+				// there is no segment in this projection document, thus one must be created
+				// need to bypass the usual infrastructure as the new segment/fragment would be of length 0 and thus the segmentation be not well formed
+				try {
+					Fragment fragment= new Fragment(0, 0);
+					fMasterDocument.addPosition(fFragmentsCategory, fragment);
+					createSegmentFor(fragment, 0);
+				} catch (BadPositionCategoryException x) {
+					internalError();
+				}
 			}
 		}
 		
@@ -704,7 +706,7 @@ public class ProjectionDocument extends AbstractDocument {
 				} catch (BadLocationException e) {
 					internalError();
 				}
-			} else if (ensureWellFormedSegmentation())
+			} else if (ensureWellFormedSegmentation(masterEvent.getOffset()))
 				fMapping.projectionChanged();
 		}
 	}
@@ -739,16 +741,28 @@ public class ProjectionDocument extends AbstractDocument {
 	 */
 	protected void updateDocumentStructures(DocumentEvent event) {
 		super.updateDocumentStructures(event);
-		ensureWellFormedSegmentation();
+		ensureWellFormedSegmentation(computeAnchor(event));
 		fMapping.projectionChanged();
 	}
 	
-	private boolean ensureWellFormedSegmentation() {
+	private int computeAnchor(DocumentEvent event) {
+		if (event instanceof ProjectionDocumentEvent) {
+			ProjectionDocumentEvent slave= (ProjectionDocumentEvent) event;
+			if (ProjectionDocumentEvent.CONTENT_CHANGE == slave.getChangeType()) {
+				DocumentEvent master= slave.getMasterEvent();
+				if (master != null)
+					return master.getOffset();
+			}
+		}
+		return -1;
+	}
+	
+	private boolean ensureWellFormedSegmentation(int anchorOffset) {
 		boolean changed= false;
 		Position[] segments= getSegments();
 		for (int i= 0; i < segments.length; i++) {
 			Segment segment= (Segment) segments[i];
-			if (segment.isDeleted()) {
+			if (segment.isDeleted() || segment.getLength() == 0) {
 				try {
 					removePosition(fSegmentsCategory, segment); 
 					fMasterDocument.removePosition(fFragmentsCategory, segment.fragment);
@@ -758,7 +772,7 @@ public class ProjectionDocument extends AbstractDocument {
 				}
 			} else if (i < segments.length - 1) {
 				Segment next= (Segment) segments[i + 1];
-				if (next.isDeleted())
+				if (next.isDeleted() || next.getLength() == 0)
 					continue;
 				Fragment fragment= segment.fragment;
 				if (fragment.getOffset() + fragment.getLength() == next.fragment.getOffset()) {
@@ -769,6 +783,22 @@ public class ProjectionDocument extends AbstractDocument {
 				}
 			}
 		}
+		
+		if (changed && anchorOffset != -1) {
+			Position[] changedSegments= getSegments();
+			if (changedSegments == null || changedSegments.length == 0) {
+				Fragment fragment= new Fragment(anchorOffset, 0);
+				try {
+					fMasterDocument.addPosition(fFragmentsCategory, fragment);
+					createSegmentFor(fragment, 0);
+				} catch (BadLocationException e) {
+					internalError();
+				} catch (BadPositionCategoryException e) {
+					internalError();
+				}
+			}
+		}
+		
 		return changed;
 	}
 
diff --git a/org.eclipse.text/projection/org/eclipse/jface/text/projection/SegmentUpdater.java b/org.eclipse.text/projection/org/eclipse/jface/text/projection/SegmentUpdater.java
index 1142a7d6999..e73f778b7e1 100644
--- a/org.eclipse.text/projection/org/eclipse/jface/text/projection/SegmentUpdater.java
+++ b/org.eclipse.text/projection/org/eclipse/jface/text/projection/SegmentUpdater.java
@@ -74,8 +74,6 @@ class SegmentUpdater extends DefaultPositionUpdater {
 				if (notDeleted())
 					adaptToReplace();
 				
-				if (fPosition.getLength() == 0)
-					fPosition.isDeleted= true;
 			}
 			
 		} catch (BadPositionCategoryException x) {