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/*******************************************************************************
* Copyright (c) 2000, 2015 IBM Corporation and others.
*
* This program and the accompanying materials
* are made available under the terms of the Eclipse Public License 2.0
* which accompanies this distribution, and is available at
* https://www.eclipse.org/legal/epl-2.0/
*
* SPDX-License-Identifier: EPL-2.0
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.jface.text;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
/**
* Abstract implementation of ILineTracker. It lets the definition of line
* delimiters to subclasses. Assuming that '\n' is the only line delimiter, this abstract
* implementation defines the following line scheme:
*
* - "" -> [0,0]
*
- "a" -> [0,1]
*
- "\n" -> [0,1], [1,0]
*
- "a\n" -> [0,2], [2,0]
*
- "a\nb" -> [0,2], [2,1]
*
- "a\nbc\n" -> [0,2], [2,3], [5,0]
*
*
* This class must be subclassed.
*
*/
public abstract class AbstractLineTracker implements ILineTracker, ILineTrackerExtension {
/**
* Tells whether this class is in debug mode.
*
* @since 3.1
*/
private static final boolean DEBUG= false;
/**
* Combines the information of the occurrence of a line delimiter. delimiterIndex
* is the index where a line delimiter starts, whereas delimiterLength,
* indicates the length of the delimiter.
* @since 3.10
*/
public static class DelimiterInfo {
public int delimiterIndex;
public int delimiterLength;
public String delimiter;
}
/**
* Representation of replace and set requests.
*
* @since 3.1
*/
protected static class Request {
public final int offset;
public final int length;
public final String text;
public Request(int offset, int length, String text) {
this.offset= offset;
this.length= length;
this.text= text;
}
public Request(String text) {
this.offset= -1;
this.length= -1;
this.text= text;
}
public boolean isReplaceRequest() {
return this.offset > -1 && this.length > -1;
}
}
/**
* Holder of the active {@link DocumentRewriteSession} with associated list of {@link Request}
* objects.
*
* On starting new {@link DocumentRewriteSession} or on the end of the active
* {@link DocumentRewriteSession} this object is being replaced by another one.
*
*
* @see AbstractLineTracker#startRewriteSession(DocumentRewriteSession)
* @see AbstractLineTracker#stopRewriteSession(DocumentRewriteSession, String)
*/
private static class SessionData {
/**
* The active rewrite session. Not final, but can only be changed to null.
*
* @since 3.1
*/
private volatile DocumentRewriteSession fActiveRewriteSession;
/**
* The list of pending requests.
*
* @since 3.1
*/
private List fPendingRequests;
/**
* @param activeRewriteSession may be null
*/
SessionData(DocumentRewriteSession activeRewriteSession){
fActiveRewriteSession = activeRewriteSession;
if (activeRewriteSession != null) {
fPendingRequests = new ArrayList<>(20);
} else {
fPendingRequests = Collections.emptyList();
}
}
boolean isSessionActive() {
return fActiveRewriteSession != null;
}
boolean setIfActive(String text) {
if (isSessionActive()) {
synchronized (this) {
if (!isSessionActive()) {
return false;
}
fPendingRequests.clear();
fPendingRequests.add(new Request(text));
}
return true;
} else {
return false;
}
}
boolean addIfActive(int offset, int length, String text) {
if (isSessionActive()) {
synchronized (this) {
if (!isSessionActive()) {
return false;
}
fPendingRequests.add(new Request(offset, length, text));
}
return true;
} else {
return false;
}
}
Iterator flush() {
synchronized (this) {
fActiveRewriteSession = null;
Iterator requests = fPendingRequests.iterator();
fPendingRequests = Collections.emptyList();
return requests;
}
}
boolean sameSession(DocumentRewriteSession session) {
return fActiveRewriteSession == session;
}
@Override
public String toString() {
StringBuilder builder= new StringBuilder();
builder.append("SessionData ["); //$NON-NLS-1$
builder.append("activeRewriteSession="); //$NON-NLS-1$
builder.append(fActiveRewriteSession);
builder.append(", "); //$NON-NLS-1$
builder.append("pendingRequests="); //$NON-NLS-1$
builder.append(fPendingRequests);
builder.append("]"); //$NON-NLS-1$
return builder.toString();
}
}
private volatile SessionData sessionData;
private final Object sessionLock = new Object();
/**
* The implementation that this tracker delegates to.
*
* @since 3.2
*/
private volatile ILineTracker fDelegate= new ListLineTracker() {
@Override
public String[] getLegalLineDelimiters() {
return AbstractLineTracker.this.getLegalLineDelimiters();
}
@Override
protected DelimiterInfo nextDelimiterInfo(String text, int offset) {
return AbstractLineTracker.this.nextDelimiterInfo(text, offset);
}
};
/**
* Whether the delegate needs conversion when the line structure is modified.
*/
private boolean fNeedsConversion= true;
/**
* Creates a new line tracker.
*/
protected AbstractLineTracker() {
sessionData = new SessionData(null);
}
@Override
public int computeNumberOfLines(String text) {
return fDelegate.computeNumberOfLines(text);
}
@Override
public String getLineDelimiter(int line) throws BadLocationException {
checkRewriteSession();
return fDelegate.getLineDelimiter(line);
}
@Override
public IRegion getLineInformation(int line) throws BadLocationException {
checkRewriteSession();
return fDelegate.getLineInformation(line);
}
@Override
public IRegion getLineInformationOfOffset(int offset) throws BadLocationException {
checkRewriteSession();
return fDelegate.getLineInformationOfOffset(offset);
}
@Override
public int getLineLength(int line) throws BadLocationException {
checkRewriteSession();
return fDelegate.getLineLength(line);
}
@Override
public int getLineNumberOfOffset(int offset) throws BadLocationException {
checkRewriteSession();
return fDelegate.getLineNumberOfOffset(offset);
}
@Override
public int getLineOffset(int line) throws BadLocationException {
checkRewriteSession();
return fDelegate.getLineOffset(line);
}
@Override
public int getNumberOfLines() {
try {
checkRewriteSession();
} catch (BadLocationException x) {
// TODO there is currently no way to communicate that exception back to the document
}
return fDelegate.getNumberOfLines();
}
@Override
public int getNumberOfLines(int offset, int length) throws BadLocationException {
checkRewriteSession();
return fDelegate.getNumberOfLines(offset, length);
}
@Override
public void set(String text) {
boolean hasActiveRewriteSession = sessionData.setIfActive(text);
if (hasActiveRewriteSession) {
return;
}
fDelegate.set(text);
}
@Override
public void replace(int offset, int length, String text) throws BadLocationException {
boolean hasActiveRewriteSession = sessionData.addIfActive(offset, length, text);
if (hasActiveRewriteSession) {
return;
}
checkImplementation();
fDelegate.replace(offset, length, text);
}
/**
* Converts the implementation to be a {@link TreeLineTracker} if it isn't yet.
*
* @since 3.2
*/
private synchronized void checkImplementation() {
if (fNeedsConversion) {
fNeedsConversion= false;
fDelegate= new TreeLineTracker((ListLineTracker) fDelegate) {
@Override
protected DelimiterInfo nextDelimiterInfo(String text, int offset) {
return AbstractLineTracker.this.nextDelimiterInfo(text, offset);
}
@Override
public String[] getLegalLineDelimiters() {
return AbstractLineTracker.this.getLegalLineDelimiters();
}
};
}
}
/**
* Returns the information about the first delimiter found in the given text starting at the
* given offset.
*
* @param text the text to be searched
* @param offset the offset in the given text
* @return the information of the first found delimiter or null
*/
protected abstract DelimiterInfo nextDelimiterInfo(String text, int offset);
@Override
public final void startRewriteSession(DocumentRewriteSession session) {
synchronized (sessionLock) {
if (sessionData.isSessionActive()){
throw new IllegalStateException("Rewrite session is already active: " + sessionData); //$NON-NLS-1$
}
sessionData = new SessionData(session);
}
}
@Override
public final void stopRewriteSession(DocumentRewriteSession session, String text) {
synchronized (sessionLock) {
if (sessionData.sameSession(session)) {
sessionData = new SessionData(null);
set(text);
}
}
}
/**
* Tells whether there's an active rewrite session.
*
* @return true if there is an active rewrite session, false
* otherwise
* @since 3.1
*/
protected final boolean hasActiveRewriteSession() {
return sessionData.isSessionActive();
}
/**
* Flushes the active rewrite session.
*
* @throws BadLocationException in case the recorded requests cannot be processed correctly
* @since 3.1
*/
protected final void flushRewriteSession() throws BadLocationException {
if (DEBUG)
System.out.println("AbstractLineTracker: Flushing rewrite session: " + sessionData); //$NON-NLS-1$
synchronized (sessionData) {
Iterator e= sessionData.flush();
while (e.hasNext()) {
Request request= e.next();
if (request.isReplaceRequest())
replace(request.offset, request.length, request.text);
else
set(request.text);
}
}
}
/**
* Checks the presence of a rewrite session and flushes it.
*
* @throws BadLocationException in case flushing does not succeed
* @since 3.1
*/
protected final void checkRewriteSession() throws BadLocationException {
if (hasActiveRewriteSession())
flushRewriteSession();
}
}