/**
 * Applies all given changes to the given document. This method assumes that 'changes' contains only changes
 * intended for the given document; the actual URI stored in the changes is ignored.
 */
public void applyAllInSameDocument(Collection<? extends IAtomicChange> changes, IDocument document)
		throws BadLocationException {
	DocumentRewriteSession rewriteSession = null;
	try {
		// prepare
		if (document instanceof IDocumentExtension4) {
			rewriteSession = ((IDocumentExtension4) document).startRewriteSession(
					DocumentRewriteSessionType.UNRESTRICTED);
		}
		// perform replacements
		for (IAtomicChange currRepl : changes) {
			currRepl.apply(document);
		}
	} finally {
		// cleanup
		if (rewriteSession != null)
			((IDocumentExtension4) document).stopRewriteSession(rewriteSession);
	}
}
 

@Override
public void apply(ITextViewer viewer, char trigger, int stateMask, int offset) {
	IDocument document = viewer.getDocument();
	// ImportsVariableResolver may add imports, so start a rewrite session if possible. 
	// This will compound all document changes in one Undo entry.
	if (document instanceof IDocumentExtension4) {
		IDocumentExtension4 docExt4 = (IDocumentExtension4) document;
		DocumentRewriteSession session = docExt4.startRewriteSession(DocumentRewriteSessionType.UNRESTRICTED);
		super.apply(viewer, trigger, stateMask, offset);
		if (session != null) {
			docExt4.stopRewriteSession(session);
		}
	} else {
		super.apply(viewer, trigger, stateMask, offset);
	}
}
 

public void doOrganizeImports(final IXtextDocument document) {
	List<ReplaceRegion> result = document.priorityReadOnly(new IUnitOfWork<List<ReplaceRegion>, XtextResource>() {
		@Override
		public List<ReplaceRegion> exec(XtextResource state) throws Exception {
			return importOrganizer.getOrganizedImportChanges(state);
		}
	});
	if (result == null || result.isEmpty())
		return;
	try {
		DocumentRewriteSession session = null;
		if(document instanceof IDocumentExtension4) {
			session = ((IDocumentExtension4)document).startRewriteSession(DocumentRewriteSessionType.UNRESTRICTED);
		}
		replaceConverter.convertToTextEdit(result).apply(document);
		if(session != null) {
			((IDocumentExtension4)document).stopRewriteSession(session);
		}
	} catch (BadLocationException e) {
		LOG.error(Messages.OrganizeImportsHandler_organizeImportsErrorMessage, e);
	}
}
 

/**
    * Sets text to a document
    * @param document
    * @param message
    * @param append
    * @throws BadLocationException
    * Has to be run from non-UI thread
    */
public static synchronized void setDocumentText(final Document document, final String message,
		final boolean append) {

	UIHelper.runUIAsync(new Runnable() {
		public void run() {
			try {
				DocumentRewriteSession rewriteSession;
				if (append && !isDefaultLabel(document)) {
					rewriteSession = document.startRewriteSession(DocumentRewriteSessionType.SEQUENTIAL);
					// append to existing document (0 length is valid and means message is going to be appended)
					document.replace(document.getLength(), 0, message + ((message.endsWith(CR)) ? EMPTY : CR));
				} else {
					rewriteSession = document.startRewriteSession(DocumentRewriteSessionType.STRICTLY_SEQUENTIAL);
					// replace of complete document
					document.replace(0, document.getLength(), message + ((message.endsWith(CR)) ? EMPTY : CR));
				}
				document.stopRewriteSession(rewriteSession);
			} catch (BadLocationException ignored) {
			}
		}
	});
}
 

@Override
public void commit(boolean onSave) {
    BusinessObjectModel workingCopy = formPage.observeWorkingCopy().getValue();
    JobSafeStructuredDocument document = (JobSafeStructuredDocument) formPage.getDocument();
    DocumentRewriteSession session = null;
    try {
        session = document.startRewriteSession(DocumentRewriteSessionType.STRICTLY_SEQUENTIAL);
        document.set(new String(formPage.getParser().marshall(formPage.getConverter().toEngineModel(workingCopy))));
        BDMArtifactDescriptor bdmArtifactDescriptor = new BDMArtifactDescriptor();
        bdmArtifactDescriptor.setGroupId(workingCopy.getGroupId());
        formPage.getEditorContribution().saveBdmArtifactDescriptor(bdmArtifactDescriptor);
    } catch (final JAXBException | IOException | SAXException e) {
        throw new RuntimeException("Fail to update the document", e);
    } finally {
        if (session != null) {
            document.stopRewriteSession(session);
        }
    }
    super.commit(onSave);
    if (onSave) {
        getManagedForm().dirtyStateChanged();
    }
}
 

/**
 * @since 2.2
 */
@Override
public void startRewriteSession(DocumentRewriteSession session) throws IllegalStateException {
	if (fActiveRewriteSession != null)
		throw new IllegalStateException();
	fActiveRewriteSession = session;
}
 

protected UndoEdit performEdits(IDocument document) throws BadLocationException, MalformedTreeException {
	DocumentRewriteSession session = null;
	try {
		if (document instanceof IDocumentExtension4) {
			session = ((IDocumentExtension4) document).startRewriteSession(DocumentRewriteSessionType.UNRESTRICTED);
		}
		return undoEdit.apply(document);
	} finally {
		if (session != null) {
			((IDocumentExtension4) document).stopRewriteSession(session);
		}
	}
}
 

/**
 * Stop a rewrite session
 */
public static void endWrite(IDocument doc, DocumentRewriteSession session) {
    if (doc instanceof IDocumentExtension4 && session != null) {
        IDocumentExtension4 d = (IDocumentExtension4) doc;
        d.stopRewriteSession(session);
    }
}
 

/**
 * Starts a rewrite session (keep things in a single undo/redo)
 */
public static DocumentRewriteSession startWrite(IDocument doc) {
    if (doc instanceof IDocumentExtension4) {
        IDocumentExtension4 d = (IDocumentExtension4) doc;
        return d.startRewriteSession(DocumentRewriteSessionType.UNRESTRICTED);
    }
    return null;
}
 

@Override
public void startRewriteSession(DocumentRewriteSession session) throws IllegalStateException {
    if (fActiveRewriteSession != null) {
        throw new IllegalStateException();
    }
    fActiveRewriteSession = session;
}
 

/**
 * {@inheritDoc}
 * <p>
 * May be extended by subclasses.
 * </p>
 */
@Override
public void stopRewriteSession(DocumentRewriteSession session) {
    if (fActiveRewriteSession == session) {
        flushRewriteSession();
    }
}
 

/**
 * @see org.eclipse.ui.IActionDelegate#run(org.eclipse.jface.action.IAction)
 */
@Override
public void run(IAction action) {
    try {
        if (!canModifyEditor()) {
            return;
        }

        PyEdit pyEdit = getPyEdit();

        PySelection ps = PySelectionFromEditor.createPySelectionFromEditor(pyEdit);
        final IDocument doc = ps.getDoc();
        if (ps.getStartLineIndex() == ps.getEndLineIndex()) {
            organizeImports(pyEdit, doc, null, ps);
        } else {
            DocumentRewriteSession session = TextSelectionUtils.startWrite(doc);
            try {
                ps.performSimpleSort(doc, ps.getStartLineIndex(), ps.getEndLineIndex());
            } finally {
                TextSelectionUtils.endWrite(doc, session);
            }
        }
    } catch (Exception e) {
        Log.log(e);
        beep(e);
    }
}
 

/**
 * {@inheritDoc}
 */
@Override
public Object execute(ExecutionEvent event) throws ExecutionException {
    try {
        ITextSelection selection = WorkbenchUtils.getActiveTextSelection();
        IDocument      doc       = WorkbenchUtils.getActiveDocument();
        IEditorInput   input     = WorkbenchUtils.getActiveInput();
        IEditorPart    editor    = WorkbenchUtils.getActiveEditor(false);

        boolean isTextOperationAllowed = (selection != null) && (doc != null) 
                                      && (input != null)     && (editor != null) 
                                      && (editor instanceof ModulaEditor);

        if (isTextOperationAllowed) {
            ITextEditor iTextEditor = (ITextEditor)editor;
            final ITextOperationTarget operationTarget = (ITextOperationTarget) editor.getAdapter(ITextOperationTarget.class);
            String commentPrefix = ((SourceCodeTextEditor)editor).getEOLCommentPrefix();
            isTextOperationAllowed = (operationTarget != null)
                                  && (operationTarget instanceof TextViewer)
                                  && (validateEditorInputState(iTextEditor))
                                  && (commentPrefix != null);
            
            if ((isTextOperationAllowed)) {
                int startLine = selection.getStartLine();
                int endLine = selection.getEndLine(); 
                int selOffset = selection.getOffset();
                int selLen = selection.getLength();
                int realEndLine = doc.getLineOfOffset(selOffset + selLen); // for selection end at pos=0 (endLine is line before here) 
                
                // Are cursor and anchor at 0 positions?
                boolean is0pos = false;
                if (doc.getLineOffset(startLine) == selOffset) {
                    if ((doc.getLineOffset(endLine) + doc.getLineLength(endLine) == selOffset + selLen)) {
                        is0pos = true;
                    }
                }
                
                
                ArrayList<ReplaceEdit> edits = null;
                int offsAfter[] = {0};
                if (is0pos || selLen == 0) {
                    edits = commentWholeLines(startLine, (selLen == 0) ? startLine : endLine, realEndLine, doc, offsAfter);
                } else {
                    edits = commentRange(selOffset, selLen, "(*", "*)", offsAfter); //$NON-NLS-1$ //$NON-NLS-2$
                }
                
                if (edits != null && !edits.isEmpty()) {
                    DocumentRewriteSession drws = null;
                    try {
                        if (doc instanceof IDocumentExtension4) {
                            drws = ((IDocumentExtension4)doc).startRewriteSession(DocumentRewriteSessionType.UNRESTRICTED);
                        }
                        MultiTextEdit edit= new MultiTextEdit(0, doc.getLength());
                        edit.addChildren((TextEdit[]) edits.toArray(new TextEdit[edits.size()]));
                        edit.apply(doc, TextEdit.CREATE_UNDO);
                        iTextEditor.getSelectionProvider().setSelection(new TextSelection(offsAfter[0], 0));
                    }
                    finally {
                        if (doc instanceof IDocumentExtension4 && drws != null) {
                            ((IDocumentExtension4)doc).stopRewriteSession(drws);
                        }
                    }
                    
                }
            }
        }
    } catch (Exception e) {
        e.printStackTrace();
    }

    return null;
}
 

/**
 * 
 * @param document
 * @param ast
 * @param begPos begin offset of the formatted area (0 to format all)
 * @param endPos end offset of the formatted area (doc.getLength() to format all)
 */
public void doFormat(IDocument doc, ModulaAst ast, int begPos, int endPos, boolean indentOnly) throws Exception {
    buildChunksModel(doc, ast, doc.getLength());
    if (chunks.size() == 0) {
        return; // Nothing to do
    }
    
    int firstChunkIdx = chunkIdxAtPos(begPos);
    int lastChunkIdx  = chunkIdxAtPos(endPos-1);

    { // Fix selection margins to include whole chunks:
        begPos = chunks.get(firstChunkIdx).getOffsetInDoc();
        Chunk c = chunks.get(lastChunkIdx);
        endPos = c.getOffsetInDoc() + c.getLengthInDoc();
    }


    if (lastChunkIdx == chunks.size()-1) {
        // chunks[lastChunkIdx+1] should always be some chunk with offset,
        // it will be required to build format edits from chunk model
        chunks.add(Chunk.createNoPlnChunkFromDoc(doc, doc.getLength(), 0));
    }
    
    // lastChunkIdx may be changed with model so use terminalChunk:
    Chunk terminalChunk = chunks.get(lastChunkIdx+1);  
   
    if (!indentOnly) {
        processNewLines(doc, firstChunkIdx, terminalChunk);
    }

    processWhitespaces(doc, firstChunkIdx, terminalChunk, indentOnly);

    if (!indentOnly) {
        processWrapLines(doc, firstChunkIdx, terminalChunk);
    }

    ArrayList<ReplaceEdit> edits = buildEditsFromModel(doc, firstChunkIdx, terminalChunk);
    
    DocumentRewriteSession drws = null;
    try {
        if (doc instanceof IDocumentExtension4) {
            drws = ((IDocumentExtension4)doc).startRewriteSession(DocumentRewriteSessionType.UNRESTRICTED);
        }
        MultiTextEdit edit= new MultiTextEdit(0, doc.getLength());
        edit.addChildren((TextEdit[]) edits.toArray(new TextEdit[edits.size()]));
        edit.apply(doc, TextEdit.CREATE_UNDO);
    }
    finally {
        if (doc instanceof IDocumentExtension4 && drws != null) {
            ((IDocumentExtension4)doc).stopRewriteSession(drws);
        }
    }
}
 

public void startRewriteSession(DocumentRewriteSession session) throws IllegalStateException {
    if (fActiveRewriteSession != null)
        throw new IllegalStateException();
    fActiveRewriteSession= session;
}
 

@Override
public DocumentRewriteSession startRewriteSession(DocumentRewriteSessionType sessionType)
        throws IllegalStateException {
    throw new RuntimeException("not implemented");
}
 

@Override
public void stopRewriteSession(DocumentRewriteSession session) {
    throw new RuntimeException("not implemented");
}
 

@Override
public DocumentRewriteSession getActiveRewriteSession() {
    throw new RuntimeException("not implemented");
}
 

/**
 * {@inheritDoc}
 * <p>
 * May be extended by subclasses.
 * </p>
 * 
 * @since 2.2
 */
@Override
public void stopRewriteSession(DocumentRewriteSession session) {
	if (fActiveRewriteSession == session)
		flushRewriteSession();
}
 

/**
 * {@inheritDoc}
 * <p>
 * May be extended by subclasses.
 * </p>
 * 
 * @since 2.2
 */
@Override
public DocumentRewriteSession getActiveRewriteSession() {
	return fActiveRewriteSession;
}
 

/**
 * {@inheritDoc}
 * <p>
 * May be extended by subclasses.
 * </p>
 */
public void stopRewriteSession(DocumentRewriteSession session) {
    if (fActiveRewriteSession == session)
        flushRewriteSession();
}
 

/**
 * {@inheritDoc}
 * <p>
 * May be extended by subclasses.
 * </p>
 */
public DocumentRewriteSession getActiveRewriteSession() {
    return fActiveRewriteSession;
}
 

/**
 * {@inheritDoc}
 * <p>
 * May be extended by subclasses.
 * </p>
 */
@Override
public DocumentRewriteSession getActiveRewriteSession() {
    return fActiveRewriteSession;
}