json/bundles/org.eclipse.wst.json.ui/src/org/eclipse/wst/json/ui/contentassist/JSONKeyCompletionProposal.java

/**
 *  Copyright (c) 2013-2015 Angelo ZERR.
 *  All rights reserved. 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:
 *  Angelo Zerr <angelo.zerr@gmail.com> - initial API and implementation
 */
package org.eclipse.wst.json.ui.contentassist;

import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.IRegion;
import org.eclipse.jface.text.ITextViewer;
import org.eclipse.jface.text.contentassist.IContextInformation;
import org.eclipse.jface.text.link.LinkedModeModel;
import org.eclipse.jface.text.link.LinkedModeUI;
import org.eclipse.jface.text.link.LinkedPosition;
import org.eclipse.jface.text.link.LinkedPositionGroup;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Point;
import org.eclipse.ui.texteditor.link.EditorLinkedModeUI;
import org.eclipse.wst.json.ui.internal.Logger;
import org.eclipse.wst.sse.ui.internal.contentassist.CustomCompletionProposal;

public class JSONKeyCompletionProposal extends CustomCompletionProposal {

	private IRegion fSelectedRegion = null;

	public JSONKeyCompletionProposal(String replacementString,
			int replacementOffset, int replacementLength, int cursorPosition,
			Image image, String displayString,
			IContextInformation contextInformation,
			String additionalProposalInfo, int relevance) {
		super(replacementString, replacementOffset, replacementLength,
				cursorPosition, image, displayString, contextInformation,
				additionalProposalInfo, relevance);
	}

	public void apply(ITextViewer viewer, char trigger, int stateMask,
			int offset) {
		super.apply(viewer, trigger, stateMask, offset);
		getLinkedPositions(viewer);
	}

	/**
	 * Sets up linked positions and installs them on the viewer.
	 * 
	 */
	protected void getLinkedPositions(ITextViewer viewer) {
		final String replacement = getReplacementString();
		final IDocument document = viewer.getDocument();
		final int length = replacement.length();
		boolean inAttribute = false, hasGroup = false;
		int offset = 0;
		char attType = 0;
		int exitPosition = -1;
		LinkedModeModel model = new LinkedModeModel();

		try {
			for (int i = 0; i < length; i++) {
				final char c = replacement.charAt(i);
				switch (c) {
				case '=':
					break;
				case '\'':
				case '\"':
					if (!inAttribute) {
						offset = i;
						attType = c;
						inAttribute = true;
					} else {
						// Found matching quotes establishing an attribute value
						// region
						if (attType == c && replacement.charAt(i - 1) != '\\') {
							inAttribute = false; // Record position length
							addPosition(model, document, getReplacementOffset()
									+ offset + 1, i - offset - 1);
							hasGroup = true;
						}
					}
					break;
				case '>':
					if (!inAttribute && exitPosition == -1) {
						exitPosition = getReplacementOffset() + i + 1;
					}
					break;
				}
			}
			if (hasGroup) {
				model.forceInstall();
				final LinkedModeUI ui = new EditorLinkedModeUI(model, viewer);
				ui.setExitPosition(viewer,
						exitPosition < 0 ? getReplacementOffset()
								+ getReplacementLength() + replacement.length()
								- 1 : exitPosition, 0, Integer.MAX_VALUE);
				ui.setCyclingMode(LinkedModeUI.CYCLE_WHEN_NO_PARENT);
				ui.setDoContextInfo(true);
				ui.enter();
				fSelectedRegion = ui.getSelectedRegion();
			}
		} catch (BadLocationException e) {
			Logger.logException(e);
		}
	}

	/**
	 * Adds a {@link LinkedPosition} to its own position group. This group is
	 * then added to the model
	 * 
	 * @param model
	 *            the linked model for this proposal
	 * @param document
	 *            the document the content assist is operating upon
	 * @param offset
	 *            the offset to establish the {@link LinkedPosition}
	 * @param length
	 *            the length of the {@link LinkedPosition}
	 * @throws BadLocationException
	 */
	private void addPosition(LinkedModeModel model, IDocument document,
			int offset, int length) throws BadLocationException {
		final LinkedPositionGroup group = new LinkedPositionGroup();
		group.addPosition(new LinkedPosition(document, offset, length,
				LinkedPositionGroup.NO_STOP));
		model.addGroup(group);
	}

	public Point getSelection(IDocument document) {
		// Attempt to return the selection based on the selected region from the
		// LinkedModeUI
		if (fSelectedRegion == null)
			return super.getSelection(document);
		return new Point(fSelectedRegion.getOffset(),
				fSelectedRegion.getLength());
	}

}